Transmitting device and transmission method

Abstract

To provide a transmission device for improving data reception quality.SOLUTION: A transmission device includes: a mapping unit; a signal processing unit; and a transmission unit. The mapping unit is configured to: when a first precoding is valid, generate a plurality of first symbols; and when the first precoding is not valid, generate a second symbol and a third symbol. The signal processing unit is configured to: when the first precoding is valid, perform the first precoding so as to generate a plurality of first precoded symbols; and when the first precoding is not valid, perform the second precoding so as to generate the second precoded symbol and the third precoded symbol. The transmission unit is configured to transmit the first precoded symbol or the second precoded symbol and the third precoded symbol. Therein the plurality of first precoded symbols is mapped respectively to a plurality of different subcarriers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates in particular to a transmitting device and a receiving device that perform communication using multiple antennas. [Background technology]

[0002] In a Line of Sight (LOS) environment where direct waves are dominant, one communication method using multiple antennas is called MIMO (Multiple-Input Multiple-Output), and one transmission method for obtaining good reception quality is the method described in Non-Patent Document 1.

[0003] Figure 17 shows an example of the configuration of a transmitting device based on the DVB-NGH (Digital Video Broadcasting - Next Generation Handheld) standard, as described in Non-Patent Literature 1, with 2 transmitting antennas and 2 transmitting modulated signals (transmitting streams). In the transmitting device, data 003 encoded by the encoding unit 002 is divided into data 005A and data 005B by the distribution unit 004. Data 005A is interleaved by the interleaver 004A and mapped by the mapping unit 006A. Similarly, data 005B is interleaved by the interleaver 004B and mapped by the mapping unit 006B. The weighted synthesis units 008A and 008B take the mapped signals 007A and 007B as input and perform weighted synthesis, respectively, to generate the weighted synthesis signals 009A and 016B. The weighted synthesis signal 016B is then phase-shifted. Then, the wireless units 010A and 010B perform processes such as OFDM (orthogonal frequency division multiplexing), frequency conversion, and amplification, and transmit signal 011A from antenna 012A and transmit signal 011B from antenna 012B.

[0004] Conventional configurations do not take into account the combined transmission of single-stream signals. In such cases, it is advisable to introduce a new transmission method, particularly to improve the data reception quality in single-stream receivers. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] “MIMO for DVB-NGH, the next generation mobile TV broadcasting,” IEEE Commun. Mag., vol.57, no.7, pp.130-137, July 2013. [Non-Patent Document 2] “Standard conformable antenna diversity techniques for OFDM and its application to the DVB-T system,” IEEE Globecom 2001, pp.3100-3105, Nov.2001. [Non-Patent Document 3] IEEE P802.11n(D3.00) Draft STANDARD for Information Technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, 2007. [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention relates to a transmission method for transmitting a single-stream signal and multiple-stream signals together when using a multi-carrier transmission method such as OFDM. The purpose of this invention is to improve the reception quality of single-stream data and to improve the reception quality of multiple-stream data in propagation environments including line-of-sight (LOS). [Means for solving the problem]

[0007] The transmitting device according to the present invention comprises a mapping unit, a signal processing unit, and a transmitting unit, wherein the mapping unit generates a plurality of first symbols by modulating a bit sequence when the first precoding is enabled in operation, and generates a second symbol and a third symbol by modulating a bit sequence when the first precoding is disabled in operation, and the signal processing unit generates a plurality of first precoded symbols, each of which is a weighted sum of the plurality of first symbols, by performing the first precoding on the plurality of first symbols when the first precoding is enabled in operation, and the first If precoding is not enabled, the second precoding is performed on the second and third symbols to generate a second precoded symbol which is a weighted sum of the second and third symbols, and a third precoded symbol which is a weighted sum of the second and third symbols. The transmitting unit then transmits the first precoded symbol, or the second and third precoded symbols, and each of the multiple first precoded symbols is mapped to a plurality of different subcarriers.

[0008] The transmission method according to the present invention is a transmission method performed by a transmitting device, and includes: a first step of generating a plurality of first symbols by modulating a bit sequence when a first precoding is effective, and generating a second symbol and a third symbol by modulating a bit sequence when the first precoding is not effective; a second step of generating a plurality of first precoded symbols, each being a weighted sum of the plurality of first symbols, by performing the first precoding on the plurality of first symbols when the first precoding is effective, and generating a second precoded symbol, which is a weighted sum of the second symbol and the third symbol, and a third precoded symbol, which is a weighted sum of the second symbol and the third symbol, by performing the second precoding on the second symbol and the third symbol when the first precoding is not effective; and a third step of transmitting the first precoded symbol, or the second precoded symbol and the third precoded symbol.

[0009] The receiving device according to the present invention comprises a receiving unit that receives a signal transmitted according to a predetermined transmission method, and a demodulation unit that demodulates the received signal. The predetermined transmission method involves applying precoding processing to a first baseband signal and a second baseband signal to generate a first precoded signal and a second precoded signal, inserting a pilot signal into the first precoded signal, setting the symbol number to i, and when i is an integer greater than or equal to 0, performing a phase change of i × Δλ on the second precoded signal, inserting a pilot signal into the second precoded signal after the phase change, and performing a phase change on the second precoded signal after the phase change and pilot signal insertion, wherein Δλ is the difference in the amount of phase change applied to two symbols with consecutive symbol numbers, satisfying π / 2 radians < Δλ < π radians, or π radians < Δλ < 3π / 2 radians. The demodulation unit performs demodulation processing according to the phase change.

[0010] The receiving method according to the present invention receives a signal transmitted according to a predetermined transmission method, in which a precoding process is applied to a first baseband signal and a second baseband signal to generate a first precoded signal and a second precoded signal, a pilot signal is inserted to the first precoded signal, the symbol number is i, and when i is an integer greater than or equal to 0, a phase shift of i × Δλ is applied to the second precoded signal, a pilot signal is inserted to the second precoded signal after the phase shift, and a phase shift is applied to the second precoded signal after the phase shift and pilot signal insertion, wherein Δλ is the difference in the amount of phase shift applied to two symbols with consecutive symbol numbers, and the process satisfies π / 2 radians < Δλ < π radians or π radians < Δλ < 3π / 2 radians, and the received signal is demodulated by performing demodulation processing according to the phase shift. [Effects of the Invention]

[0011] Thus, according to the present invention, it is possible to improve the reception quality of single-stream data and also improve the reception quality of multiple stream data in propagation environments including LOS (line-of-sight), thereby enabling the provision of high-quality communication services. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows an example configuration of the transmitting device in this embodiment. [Figure 2] Figure 2 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 3] Figure 3 shows an example configuration of the wireless unit shown in Figure 1. [Figure 4] Figure 4 shows an example of a single frame configuration of the transmitted signal shown in Figure 1. [Figure 5] Figure 5 shows an example of a single frame configuration of the transmitted signal shown in Figure 1. [Figure 6] Figure 6 shows an example configuration of the control information generation part of Figure 2. [Figure 7] Figure 7 shows an example configuration of the antenna section shown in Figure 1. [Figure 8] Figure 8 shows an example configuration of the receiving device in this embodiment. [Figure 9] Figure 9 is a diagram showing the relationship between the transmitting device and the receiving device. [Figure 10] Figure 10 shows an example configuration of the antenna section shown in Figure 8. [Figure 11] Figure 11 shows a portion of the frame in Figure 5. [Figure 12] Figure 12 shows an example of a modulation scheme used in the mapping section of Figure 1. [Figure 13] Figure 13 shows an example of a single frame configuration of the transmitted signal shown in Figure 1. [Figure 14] Figure 14 shows an example of a single frame configuration of the transmitted signal in Figure 1. [Figure 15]Figure 15 shows an example configuration using a CCD. [Figure 16] Figure 16 shows an example of a single carrier configuration using OFDM. [Figure 17] Figure 17 shows an example configuration of a transmitter based on the DVB-NGH standard. [Figure 18] Figure 18 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 19] Figure 19 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 20] Figure 20 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 21] Figure 21 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 22] Figure 22 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 23] Figure 23 shows an example of a base station configuration. [Figure 24] Figure 24 shows an example of a terminal configuration. [Figure 25] Figure 25 shows an example of the frame structure of a modulated signal. [Figure 26] Figure 26 shows an example of communication between a base station and a terminal. [Figure 27] Figure 27 shows an example of communication between a base station and a terminal. [Figure 28] Figure 28 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 29] Figure 29 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 30] Figure 30 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 31] Figure 31 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 32] Figure 32 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 33] Figure 33 shows an example configuration of the signal processing unit shown in Figure 1. [Figure 34]Figure 34 shows an example of a system configuration when a base station and a terminal are communicating. [Figure 35] Figure 35 shows an example of communication between a base station and a terminal. [Figure 36] Figure 36 shows an example of the data contained in the reception capability notification symbol transmitted by the terminal shown in Figure 35. [Figure 37] Figure 37 shows an example of the data contained in the reception capability notification symbol transmitted by the terminal shown in Figure 35. [Figure 38] Figure 38 shows an example of the data contained in the reception capability notification symbol transmitted by the terminal shown in Figure 35. [Figure 39] Figure 39 shows an example of the frame configuration of the transmitted signal in Figure 1. [Figure 40] Figure 40 shows an example of the frame configuration of the transmitted signal in Figure 1. [Figure 41] Figure 41 shows an example of the configuration of the terminal's receiving device in Figure 24. [Figure 42] Figure 42 shows an example of a frame configuration when a base station or AP uses a multi-carrier transmission scheme to transmit a single-modulated signal. [Figure 43] Figure 43 shows an example of a frame configuration when a base station or AP transmits a single-modulated signal using a single-carrier transmission scheme. [Figure 44] Figure 44 shows an example of the configuration of transmitting equipment such as base stations, access points, and broadcasting stations. [Figure 45] Figure 45 shows an example of how symbols are arranged relative to the time axis of a signal. [Figure 46] Figure 46 shows an example of how symbols are arranged relative to the frequency axis of a signal. [Figure 47] Figure 47 shows an example of the arrangement of symbols on the time and frequency axes of a signal. [Figure 48] Figure 48 shows a second example of the arrangement of symbols in relation to the time of a signal. [Figure 49]Figure 49 shows a second example of the arrangement of symbols with respect to signal frequency. [Figure 50] Figure 50 shows an example of the arrangement of symbols for a signal in relation to its time and frequency. [Figure 51] Figure 51 shows an example of the configuration of a modulated signal transmitted by a base station or AP. [Figure 52] Figure 52 shows an example of the frame configuration when "Single-stream modulated signal transmission 5101" is shown in Figure 51. [Figure 53] Figure 53 shows an example of the frame configuration when "Multiple Modulated Signal Transmission 5102 for Multiple Streams" is shown in Figure 51. [Figure 54] Figure 54 shows an example of the configuration of the signal processing unit in a base station's transmitting device. [Figure 55] Figure 55 shows an example of the configuration of the wireless unit. [Figure 56] Figure 56 shows an example of the configuration of the signal processing unit in a base station's transmitting device. [Figure 57] Figure 57 shows an example of the configuration of a modulated signal transmitted by a base station or access point (AP). [Figure 58] Figure 58 shows an example of the frame configuration when "Single-stream modulated signal transmission 5701" is shown in Figure 57. [Figure 59] Figure 59 shows a first example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 60] Figure 60 shows a second example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 61] Figure 61 shows a third example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 62] Figure 62 shows a fourth example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 63] Figure 63 shows a fifth example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 64]Figure 64 shows a sixth example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 65] Figure 65 shows a seventh example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 66] Figure 66 shows an eighth example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 67] Figure 67 shows a ninth example in which the phase shifting section is placed before and after the weighting synthesis section. [Figure 68] Figure 68 is a diagram illustrating the operation of the mapping unit in Figure 1. [Figure 69] Figure 69 shows an example of signal point arrangement for QPSK in the in-phase I-orthogonal Q plane. [Figure 70] Figure 70 shows an example of signal point arrangement for QPSK in the in-phase I-orthogonal Q plane. [Figure 71] Figure 71 shows an example of signal point arrangement for QPSK in the in-phase I-orthogonal Q plane. [Figure 72] Figure 72 shows an example of signal point arrangement for QPSK in the in-phase I-orthogonal Q plane. [Figure 73] Figure 73 shows an example of the configuration of a base station or AP (Access Point) transmitting device. [Figure 74] Figure 74 is a diagram illustrating the operation of the mapping unit in Figure 73. [Figure 75] Figure 75 is a diagram illustrating the operation of the mapping unit shown in Figure 73. [Figure 76] Figure 76 is a diagram illustrating the operation of the mapping unit in Figure 1. [Figure 77] Figure 77 is a diagram illustrating the operation of the mapping unit in Figure 73. [Figure 78] Figure 78 is a diagram illustrating the operation of the mapping unit shown in Figure 73. [Figure 79] Figure 79 shows an example of the data contained in the "receiving capability notification symbol" transmitted by the terminal shown in Figure 35. [Figure 80]Figure 80 shows an example of a frame configuration. [Figure 81] Figure 81 shows an example of the frame configuration of the transmitted signal in Figure 1. [Figure 82] Figure 82 shows an example of the frame configuration of the transmitted signal in Figure 1. [Figure 83] Figure 83 shows the spectrum of the transmitted signal in Figure 1. [Figure 84] Figure 84 shows the signal point arrangement in the common-mode I-orthogonal Q plane when using BPSK. [Figure 85] Figure 85 shows the signal point arrangement when the symbol number i is even. [Figure 86] Figure 86 shows the signal points of the precoded signal in the common-mode I-orthogonal Q plane when using BPSK. [Figure 87] Figure 87 shows the signal points in the in-phase I-orthogonal Q-plane of the weighted combined signal. [Figure 88] Figure 88 shows an example of the frame structure of a transmission signal sent by a base station or AP. [Figure 89] Figure 89 shows an example of the configuration of a receiving device. [Figure 90] Figure 90 shows an example of the configuration of a transmitting device. [Figure 91] Figure 91 shows an example of the configuration of the signal processing unit in Figure 90. [Figure 92] Figure 92 shows an example of the frame configuration of the modulated signal transmitted by the transmitting device shown in Figure 90. [Figure 93] Figure 93 shows an example of the frame configuration of the modulated signal transmitted by the transmitter shown in Figure 90. [Figure 94] Figure 94 shows a specific example of the configuration of the reception capability notification symbol transmitted by the terminal shown in Figure 35. [Figure 95] Figure 95 shows an example of the configuration of the "receiving capability notification symbols related to single-carrier and OFDM schemes" shown in Figure 94. [Figure 96]Figure 96 shows an example of the configuration of the "receiving capability notification symbol related to the single-carrier system" shown in Figure 94. [Figure 97] Figure 97 shows an example of the configuration of the "Receiving capability notification symbol for OFDM scheme" shown in Figure 94. [Figure 98] Figure 98 shows a specific example of the configuration of the reception capability notification symbol transmitted by the terminal shown in Figure 35. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0014] (Embodiment 1) The transmission method, transmission device, reception method, and reception device of this embodiment will be described in detail below.

[0015] Figure 1 shows an example of the configuration of a transmitting device such as a base station, access point, or broadcasting station in this embodiment. The error correction coding unit 102 takes data 101 and control signal 100 as input, performs error correction coding based on information about the error correction code contained in the control signal 100 (for example, information about the error correction code, code length (block length), coding rate), and outputs coded data 103. The error correction coding unit 102 may also be equipped with an interleaver, and if an interleaver is equipped, it may rearrange the data after coding and output coded data 103.

[0016] The mapping unit 104 receives encoded data 103 and control signal 100 as input, performs mapping corresponding to the modulation scheme based on the information of the modulation signal contained in the control signal 100, and outputs the mapped signal (baseband signal) 105_1 and the mapped signal (baseband signal) 105_2. The mapping unit 104 generates the mapped signal 105_1 using the first sequence and generates the mapped signal 105_2 using the second sequence. In this case, the first sequence and the second sequence are different.

[0017] The signal processing unit 106 takes the mapped signals 105_1 and 105_2, the signal group 110, and the control signal 100 as inputs, performs signal processing based on the control signal 100, and outputs the processed signals 106_A and 106_B. In this case, the processed signal 106_A is represented as u1(i) and the processed signal 106_B is represented as u2(i) (where i is a symbol number, for example, i is a non-negative integer). The signal processing will be explained later using Figure 2.

[0018] The wireless unit 107_A receives the processed signal 106_A and the control signal 100 as inputs, processes the processed signal 106_A based on the control signal 100, and outputs the transmission signal 108_A. The transmission signal 108_A is then output as radio waves from the antenna unit #A (109_A).

[0019] Similarly, the wireless unit 107_B receives the processed signal 106_B and the control signal 100 as inputs, processes the processed signal 106_B based on the control signal 100, and outputs the transmission signal 108_B. The transmission signal 108_B is then output as radio waves from the antenna unit #B (109_B).

[0020] Antenna unit #A(109_A) receives control signal 100 as input. In this case, it processes the transmission signal 108_A based on control signal 100 and outputs it as radio waves. However, antenna unit #A(109_A) does not necessarily need to receive control signal 100 as input.

[0021] Similarly, antenna unit #B(109_B) receives control signal 100 as input. In this case, it processes the transmission signal 108_B based on control signal 100 and outputs radio waves. However, antenna unit #B(109_B) does not necessarily need to receive control signal 100 as input.

[0022] The control signal 100 may be generated based on information transmitted by the communication partner device in Figure 1, or the device in Figure 1 may have an input unit and the control signal 100 may be generated based on information input from that input unit.

[0023] Figure 2 shows an example of the configuration of the signal processing unit 106 in Figure 1. The weighted synthesis unit (precoding unit) 203 takes the mapped signal 201A (corresponding to the mapped signal 105_1 in Figure 1), the mapped signal 201B (corresponding to the mapped signal 105_2 in Figure 1), and the control signal 200 (corresponding to the control signal 100 in Figure 1) as inputs, performs weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. In this case, the mapped signal 201A is represented as s1(t), the mapped signal 201B as s2(t), the weighted signal 204A as z1(t), and the weighted signal 204B as z2'(t). Note that t is time as an example. (s1(t), s2(t), z1(t), and z2'(t) are defined as complex numbers. (Therefore, they may also be real numbers.))

[0024] The weighted composition unit (precoding unit) 203 will perform the following calculations.

[0025]

number

[0026] In equation (1), a, b, c, and d can be defined as complex numbers, and therefore, a, b, c, and d are defined as complex numbers. (They may also be real numbers.) i is the symbol number.

[0027] The phase shifting unit 205B receives the weighted combined signal 204B and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204B and outputs the phase-shifted signal 206B. The phase-shifted signal 206B is denoted by z2(t), and z2(t) is defined as a complex number. (It may also be a real number.)

[0028] The specific operation of the phase shifting unit 205B will now be explained. For example, the phase shifting unit 205B applies a phase shift of y(i) to z2'(i). Therefore, z2(i) can be expressed as z2(i) = y(i) × z2'(i). (i is the symbol number; i is a non-negative integer.)

[0029] For example, set the phase shift value as follows: (N is an integer greater than or equal to 2, and N represents the phase shift period.) (Setting N to an odd number greater than or equal to 3 may improve data reception quality.)

[0030]

number

[0031] In this case, z1(i) and z2(i) can be expressed by the following equations.

[0032]

number

[0033] Note that δ(i) is a real number. Furthermore, z1(i) and z2(i) will be transmitted from the transmitting device at the same time and at the same frequency (same frequency band).

[0034] In equation (3), the phase change value is not limited to that in equation (2); for example, a method of periodically and regularly changing the phase is also possible.

[0035] (Precoding) matrices in equations (1) and (3).

number

[0036]

number

number

number

number

number

number

number

number

[0037] In equations (5), (6), (7), (8), (9), (10), (11), and (12), α may be a real number or an imaginary number, and β may be a real number or an imaginary number. However, α is not 0 (zero), and β is also not 0 (zero). or

number

number

number

number

number

number

number

number

[0038] In equations (13), (15), (17), and (19), β may be a real number or an imaginary number. However, β is not 0 (zero). (θ is a real number) or

number

number

number

number

number

number

number

number

number

number

number

number

[0039] However, θ 11 (i), θ 21 (i) λ(i) is a function of i (symbol number) (real number), λ is a fixed value (real number) (but does not have to be a fixed value), α may be a real number or an imaginary number, and β may be a real number or an imaginary number, provided that α is not 0 (zero) and β is also not 0 (zero). Also, θ 11 θ 21 It is a real number.

[0040] Furthermore, each embodiment of this specification can be implemented using precoding matrices other than those specified. or

number

number

number

number

[0041] Note that β in equations (34) and (36) may be a real number or an imaginary number. However, β is not 0 (zero).

[0042] The insertion unit 207A receives the weighted combined signal 204A, the pilot symbol signal (pa(t)) (t: time) (251A), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208A based on the frame configuration information contained in the control signal 200.

[0043] Similarly, the insertion unit 207B receives the phase-shifted signal 206B, the pilot symbol signal (pb(t)(251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208B based on the frame configuration information contained in the control signal 200.

[0044] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i), where j is the imaginary unit.

[0045] As will be explained later, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0046] Figure 3 shows an example of the configuration of the wireless units 107_A and 107_B in Figure 1. The serial-to-parallel converter 302 receives signal 301 and control signal 300 (corresponding to control signal 100 in Figure 1) as inputs, performs serial-to-parallel conversion based on control signal 300, and outputs the converted signal 303.

[0047] The inverse Fourier transform unit 304 receives the signal 303 after serial-to-parallel conversion and the control signal 300 as inputs, performs an inverse Fourier transform (for example, an inverse fast Fourier transform (IFFT)) based on the control signal 300, and outputs the signal 305 after the inverse Fourier transform.

[0048] The processing unit 306 receives the inverse Fourier transform signal 305 and the control signal 300 as inputs, performs processing such as frequency conversion and amplification based on the control signal 300, and outputs the modulated signal 307.

[0049] (For example, if signal 301 is signal 106_A after signal processing in Figure 1, then modulated signal 307 corresponds to transmitted signal 108_A in Figure 1. Also, if signal 301 is signal 106_B after signal processing in Figure 1, then modulated signal 307 corresponds to transmitted signal 108_B in Figure 1.)

[0050] Figure 4 shows the frame structure of the transmitted signal 108_A in Figure 1. In Figure 4, the horizontal axis represents frequency (carrier), and the vertical axis represents time. Because a multi-carrier transmission method such as OFDM is used, symbols exist in the carrier direction. Figure 4 shows the symbols for carriers 1 through 36. Also, Figure 4 shows the symbols for time points $1 through $11.

[0051] In Figure 4, 401 represents the pilot symbol (corresponding to the pilot signal 251A (pa(t)) in Figure 2), 402 represents the data symbol, and 403 represents other symbols. In this case, the pilot symbol is, for example, a PSK (Phase Shift Keying) symbol, and is a symbol used by the receiving device that receives this frame to perform channel estimation (estimation of propagation path variation) and frequency offset / phase variation estimation. For example, it is desirable that the transmitting device in Figure 1 and the receiving device that receives the frame in Figure 4 share the same method for transmitting the pilot symbol.

[0052] By the way, we will name the mapped signal 201A (mapped signal 105_1 in Figure 1) "Stream #1" and the mapped signal 201B (mapped signal 105_2 in Figure 1) "Stream #2". This will also be the case in the following explanation.

[0053] The data symbol 402 is a symbol corresponding to the baseband signal 208A generated by the signal processing shown in Figure 2. Therefore, the data symbol 402 is either a symbol containing both the symbol for "Stream #1" and the symbol for "Stream #2", or a symbol for "Stream #1", or a symbol for "Stream #2", which is determined by the configuration of the precoding matrix used in the weighted synthesis unit 203.

[0054] Other symbols 403 are symbols corresponding to the preamble signal 242 and the control information symbol signal 253 in Figure 2. (However, other symbols may include symbols other than the preamble and control information symbols.) In this case, the preamble may transmit (control) data, and may consist of symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations). The control information symbols are symbols that contain control information for the receiving device that receives the frame in Figure 4 to demodulate and decode the data symbols.

[0055] For example, in Figure 4, carriers 1 to 36 from time $1 to time 4 become other symbols 403. Then, carriers 1 to 11 at time $5 become data symbols 402. Subsequently, carrier 12 at time $5 becomes pilot symbol 401, carriers 13 to 23 at time $5 become data symbols 402, carrier 24 at time $5 becomes pilot symbol 401, ..., carriers 1 and 2 at time $6 become data symbols 402, carrier 3 at time $6 becomes pilot symbol 401, ..., carrier 30 at time $11 becomes pilot symbol 401, and carriers 31 to 36 at time $11 become data symbols 402.

[0056] Figure 5 shows the frame structure of the transmitted signal 108_B in Figure 1. In Figure 5, the horizontal axis represents frequency (carrier), and the vertical axis represents time. Because a multi-carrier transmission method such as OFDM is used, symbols exist in the carrier direction. Figure 5 shows the symbols for carriers 1 through 36. Also, Figure 5 shows the symbols for time points $1 through $11.

[0057] In Figure 5, 501 represents the pilot symbol (corresponding to the pilot signal 251B (pb(t)) in Figure 2), 502 represents the data symbol, and 503 represents other symbols. In this case, the pilot symbol is, for example, a PSK symbol, and is a symbol used by the receiving device that receives this frame to perform channel estimation (estimation of propagation path variation) and frequency offset / phase variation estimation. For example, it is desirable that the transmitting device in Figure 1 and the receiving device that receives the frame in Figure 5 share the same method for transmitting the pilot symbol.

[0058] The data symbol 502 is a symbol corresponding to the baseband signal 208B generated by the signal processing shown in Figure 2. Therefore, the data symbol 502 is either a symbol containing both the symbol for "Stream #1" and the symbol for "Stream #2", or a symbol for "Stream #1", or a symbol for "Stream #2", which is determined by the configuration of the precoding matrix used in the weighted synthesis unit 203.

[0059] Other symbols 503 are symbols corresponding to the preamble signal 252 and the control information symbol signal 253 in Figure 2. (However, other symbols may include symbols other than the preamble and control information symbols.) In this case, the preamble may transmit (control) data, and may consist of symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations). The control information symbols are symbols that contain control information for the receiving device that receives the frame in Figure 5 to demodulate and decode the data symbols.

[0060] For example, in Figure 5, carriers 1 to 36 from time $1 to time 4 become other symbols 403. Then, carriers 1 to 11 at time $5 become data symbols 402. Subsequently, carrier 12 at time $5 becomes pilot symbol 401, carriers 13 to 23 at time $5 become data symbols 402, carrier 24 at time $5 becomes pilot symbol 401, ..., carriers 1 and 2 at time $6 become data symbols 402, carrier 3 at time $6 becomes pilot symbol 401, ..., carrier 30 at time $11 becomes pilot symbol 401, and carriers 31 to 36 at time $11 become data symbols 402.

[0061] When a symbol exists on carrier A at time $B in Figure 4, and a symbol exists on carrier A at time $B in Figure 5, the symbols on carrier A at time $B in Figure 4 and the symbols on carrier A at time $B in Figure 5 will be transmitted at the same time and on the same frequency. Note that the frame configuration is not limited to Figures 4 and 5; Figures 4 and 5 are merely examples of frame configurations.

[0062] Furthermore, the other symbols in Figures 4 and 5 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 5 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 4, then it will be transmitting the same data (same control information).

[0063] It is assumed that the receiving device will receive the frames in Figure 4 and Figure 5 simultaneously, but the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 4 or only the frames in Figure 5.

[0064] Figure 6 shows an example of the configuration of the control information generation part for generating the control information symbol signal 253 shown in Figure 2.

[0065] The control information mapping unit 602 receives control information data 601 and control signals 600 as inputs, applies a mapping to the control information data 601 using a modulation scheme based on the control signals 600, and outputs a signal 603 after the control information mapping. The signal 603 after the control information mapping corresponds to the control information symbol signal 253 in Figure 2.

[0066] Figure 7 shows an example of the configuration of antenna section #A (109_A) and antenna section #B (109_B) in Figure 1. (This is an example where antenna section #A (109_A) and antenna section #B (109_B) are composed of multiple antennas.)

[0067] The distribution unit 702 takes the transmission signal 701 as input, distributes it, and outputs transmission signals 703_1, 703_2, 703_3, and 703_4.

[0068] The multiplication unit 704_1 receives the transmission signal 703_1 and the control signal 700 as inputs. Based on the information of the multiplication coefficient contained in the control signal 700, it multiplies the transmission signal 703_1 by the multiplication coefficient and outputs the multiplied signal 705_1. The multiplied signal 705_1 is then output as radio waves from the antenna 706_1.

[0069] If the transmitted signal 703_1 is Tx1(t) (t: time) and the multiplication coefficient is W1 (W1 can be defined as a complex number and therefore may be a real number), then the signal 705_1 after multiplication can be expressed as Tx1(t) × W1.

[0070] The multiplication unit 704_2 receives the transmission signal 703_2 and the control signal 700 as inputs. Based on the information of the multiplication coefficient contained in the control signal 700, it multiplies the transmission signal 703_2 by the multiplication coefficient and outputs the multiplied signal 705_2. The multiplied signal 705_2 is then output as radio waves from the antenna 706_2.

[0071] If the transmitted signal 703_2 is Tx2(t) and the multiplication coefficient is W2 (W2 can be defined as a complex number and therefore may be a real number), then the signal 705_2 after multiplication can be expressed as Tx2(t) × W2.

[0072] The multiplication unit 704_3 receives the transmission signal 703_3 and the control signal 700 as inputs. Based on the information of the multiplication coefficient contained in the control signal 700, it multiplies the transmission signal 703_3 by the multiplication coefficient and outputs the multiplied signal 705_3. The multiplied signal 705_3 is then output as radio waves from the antenna 706_3.

[0073] If the transmitted signal 703_3 is Tx3(t) and the multiplication coefficient is W3 (W3 can be defined as a complex number and therefore may be a real number), then the signal 705_3 after multiplication can be expressed as Tx3(t) × W3.

[0074] The multiplication unit 704_4 receives the transmission signal 703_4 and the control signal 700 as inputs. Based on the information of the multiplication coefficient contained in the control signal 700, it calculates the multiplication coefficient for the transmission signal 703_4 and outputs the multiplied signal 705_4. The multiplied signal 705_4 is then output as radio waves from the antenna 706_4.

[0075] If the transmitted signal 703_4 is Tx4(t) and the multiplication coefficient is W4 (W4 can be defined as a complex number and therefore may be a real number), then the signal 705_4 after multiplication can be expressed as Tx4(t) × W4.

[0076] Note that the absolute values ​​of W1, W2, W3, and W4 may also be equal. In this case, a phase shift has occurred. (Of course, the absolute values ​​of W1, W2, W3, and W4 do not necessarily have to be equal.)

[0077] Furthermore, while Figure 7 illustrates an example where the antenna section consists of four antennas (and four multiplier units), the number of antennas is not limited to four; it can consist of two or more antennas.

[0078] Furthermore, when the configuration of antenna unit #A (109_A) in Figure 1 is as shown in Figure 7, the transmitted signal 701 corresponds to the transmitted signal 108_A in Figure 1. Also, when the configuration of antenna unit #B (109_B) in Figure 1 is as shown in Figure 7, the transmitted signal 701 corresponds to the transmitted signal 108_B in Figure 1. However, antenna unit #A (109_A) and antenna unit #B (109_B) do not have to be configured as shown in Figure 7, and as previously mentioned, the antenna unit does not have to accept the control signal 100 as input.

[0079] Figure 8 shows an example of the configuration of a receiving device that receives a modulated signal when the transmitting device in Figure 1 transmits a transmission signal with the frame configuration shown in Figures 4 and 5.

[0080] The wireless unit 803X receives the received signal 802X from the antenna unit #X (801X) as input, performs processing such as frequency conversion and Fourier transform, and outputs the baseband signal 804X.

[0081] Similarly, the wireless unit 803Y takes the received signal 802Y received by the antenna unit #Y (801Y) as input, performs processing such as frequency conversion and Fourier transform, and outputs the baseband signal 804Y.

[0082] Although Figure 8 shows antenna units #X (801X) and #Y (801Y) configured to receive control signal 810 as input, they may also be configured without receiving control signal 810 as input. The operation when control signal 810 is present as input will be explained in detail later.

[0083] By the way, Figure 9 shows the relationship between the transmitting and receiving devices. Antennas 901_1 and 901_2 in Figure 9 are transmitting antennas, and antenna 901_1 in Figure 9 corresponds to antenna section #A (109_A) in Figure 1. Antenna 901_2 in Figure 9 corresponds to antenna section #B (109_B) in Figure 1.

[0084] Furthermore, antennas 902_1 and 902_2 in Figure 9 are receiving antennas, with antenna 902_1 in Figure 9 corresponding to antenna section #X (801X) in Figure 8. And antenna 902_2 in Figure 9 corresponds to antenna section #Y (801Y) in Figure 8.

[0085] As shown in Figure 9, let u1(i) be the signal transmitted from transmitting antenna 901_1, u2(i) be the signal transmitted from transmitting antenna 901_2, r1(i) be the signal received by receiving antenna 902_1, and r2(i) be the signal received by receiving antenna 902_2. Note that i represents the symbol number and is, for example, a non-negative integer.

[0086] Let h11(i) be the propagation coefficient from transmitting antenna 901_1 to receiving antenna 902_1, h21(i) be the propagation coefficient from transmitting antenna 901_1 to receiving antenna 902_2, h12(i) be the propagation coefficient from transmitting antenna 901_2 to receiving antenna 902_1, and h22(i) be the propagation coefficient from transmitting antenna 901_2 to receiving antenna 902_2. Then the following relationship holds.

[0087]

number

[0088] Note that n1(i) and n2(i) are noise.

[0089] The channel estimation unit 805_1 for the modulated signal u1 in Figure 8 takes the baseband signal 804X as input and estimates the channel of the modulated signal u1, i.e., h11(i) in equation (37), using the preamble and / or pilot symbol in Figures 4 and 5, and outputs the channel estimation signal 806_1.

[0090] The channel estimation unit 805_2 for the modulated signal u2 takes the baseband signal 804X as input and estimates the channel of the modulated signal u2, i.e., h12(i) in equation (37), using the preamble and / or pilot symbols shown in Figures 4 and 5, and outputs the channel estimation signal 806_2.

[0091] The channel estimation unit 807_1 for the modulated signal u1 takes the baseband signal 804Y as input and estimates the channel of the modulated signal u1, i.e., h21(i) in equation (37), using the preamble and / or pilot symbols shown in Figures 4 and 5, and outputs the channel estimation signal 808_1.

[0092] The channel estimation unit 807_2 for the modulated signal u2 takes the baseband signal 804Y as input and estimates the channel of the modulated signal u2, that is, h22(i) in equation (37), using the preamble and / or pilot symbol shown in Figures 4 and 5, and outputs the channel estimation signal 808_2.

[0093] The control information decoding unit 809 receives baseband signals 804X and 804Y as input, demodulates and decodes the control information included in "other symbols" in Figures 4 and 5, and outputs a control signal 810 containing the control information.

[0094] The signal processing unit 811 takes the channel estimation signals 806_1, 806_2, 808_1, 808_2, baseband signals 804X, 804Y, and control signal 810 as input, and performs demodulation and decoding using the relationship in equation (37) and based on the control information in the control signal 810 (for example, information related to the modulation scheme and error correction code), and outputs the received data 812.

[0095] Note that the control signal 810 does not have to be generated in the manner shown in Figure 8. For example, the control signal 810 in Figure 8 may be generated based on information transmitted by the device that is the communication partner (Figure 1) in Figure 8, or the device in Figure 8 may have an input unit and the control signal 810 may be generated based on information input from that input unit.

[0096] Figure 10 shows an example of the configuration of antenna section #X (801X) and antenna section #Y (801Y) in Figure 8. (This is an example where antenna section #X (801X) and antenna section #Y (801Y) are composed of multiple antennas.)

[0097] The multiplication unit 1003_1 receives the received signal 1002_1 and the control signal 1000 from the antenna 1001_1 as inputs. Based on the information of the multiplication coefficient contained in the control signal 1000, it multiplies the received signal 1002_1 by the multiplication coefficient and outputs the multiplied signal 1004_1.

[0098] If the received signal 1002_1 is Rx1(t) (t: time) and the multiplication coefficient is D1 (D1 can be defined as a complex number and therefore may be a real number), then the signal 1004_1 after multiplication can be expressed as Rx1(t) × D1.

[0099] The multiplication unit 1003_2 receives the received signal 1002_2 and the control signal 1000 from the antenna 1001_2 as inputs. Based on the information of the multiplication coefficient contained in the control signal 1000, it multiplies the received signal 1002_2 by the multiplication coefficient and outputs the multiplied signal 1004_2.

[0100] If the received signal 1002_2 is Rx2(t) and the multiplication coefficient is D2 (where D2 can be defined as a complex number and therefore may be a real number), then the signal 1004_2 after multiplication can be expressed as Rx2(t) × D2.

[0101] The multiplication unit 1003_3 receives the received signal 1002_3 and the control signal 1000 from the antenna 1001_3 as inputs. Based on the information of the multiplication coefficient contained in the control signal 1000, it multiplies the received signal 1002_3 by the multiplication coefficient and outputs the multiplied signal 1004_3.

[0102] If the received signal 1002_3 is Rx3(t) and the multiplication coefficient is D3 (where D3 can be defined as a complex number and therefore may be a real number), then the signal 1004_3 after multiplication can be expressed as Rx3(t) × D3.

[0103] The multiplication unit 1003_4 receives the received signal 1002_4 and the control signal 1000 from the antenna 1001_4 as inputs. Based on the information of the multiplication coefficient contained in the control signal 1000, it multiplies the received signal 1002_4 by the multiplication coefficient and outputs the multiplied signal 1004_4.

[0104] If the received signal 1002_4 is Rx4(t) and the multiplication coefficient is D4 (where D4 can be defined as a complex number and therefore may be a real number), then the signal 1004_4 after multiplication can be expressed as Rx4(t) × D4.

[0105] The combining unit 1005 takes the multiplied signals 1004_1, 1004_2, 1004_3, and 1004_4 as input, combines the multiplied signals 1004_1, 1004_2, 1004_3, and 1004_4, and outputs the combined signal 1006. The combined signal 1006 can be expressed as Rx1(t)×D1+Rx2(t)×D2+Rx3(t)×D3+Rx4(t)×D4.

[0106] Figure 10 illustrates an example where the antenna section consists of four antennas (and four multipliers), but the number of antennas is not limited to four; it can consist of two or more antennas.

[0107] Furthermore, when the configuration of antenna unit #X(801X) in Figure 8 is as shown in Figure 10, the received signal 802X corresponds to the combined signal 1006 in Figure 10, and the control signal 710 corresponds to the control signal 1000 in Figure 10. Also, when the configuration of antenna unit #Y(801Y) in Figure 8 is as shown in Figure 10, the received signal 802Y corresponds to the combined signal 1006 in Figure 10, and the control signal 710 corresponds to the control signal 1000 in Figure 10. However, antenna unit #X(801X) and antenna unit #Y(801Y) do not have to be configured as shown in Figure 10, and as previously mentioned, the antenna unit does not have to take the control signal 710 as input.

[0108] The control signal 800 may be generated based on information transmitted by the communication partner device, or the device may be equipped with an input unit and the control signal 800 may be generated based on information input from that input unit.

[0109] Next, as shown in Figure 1, the signal processing unit 106 of the transmitting device has phase shifting units 205B and 209B inserted, as shown in Figure 2. We will now explain its features and the effects it has.

[0110] As explained using Figures 4 and 5, the phase shifting unit 205B performs precoding (weighted synthesis) on the mapped signal s1(i)(201A) (where i is the symbol number and i is a non-negative integer) obtained by mapping using the first sequence and the mapped signal s2(i)(201B) obtained by mapping using the second sequence, and then performs a phase shift on one of the resulting weighted synthesized signals 204A and 204B. The weighted synthesized signal 204A and the phase-shifted signal 206B are then transmitted at the same frequency and at the same time. Therefore, in Figures 4 and 5, the phase shift is applied to the data symbol 502 in Figure 5. (In the case of Figure 2, the phase shifting unit 205B is applied to the weighted and combined signal 204B, so the phase shift is applied to the data symbol 502 in Figure 5. If the phase shift is applied to the weighted and combined signal 204A, the phase shift will be applied to the data symbol 402 in Figure 4. This point will be explained later.)

[0111] For example, Figure 11 shows the frame from Figure 5 with carriers 1 through 5 and time points $4 through $6 extracted. As with Figure 5, 501 is the pilot symbol, 502 is the data symbol, and 503 is the other symbol.

[0112] As described above, in the symbols shown in FIG. 11, for the data symbols of (Carrier 1, Time $5), (Carrier 2, Time $5), (Carrier 3, Time $5), (Carrier 4, Time $5), (Carrier 5, Time $5), (Carrier 1, Time $6), (Carrier 2, Time $6), (Carrier 4, Time $6), and (Carrier 5, Time $6), the phase change unit 205B will perform phase change.

[0113] Therefore, in the symbols shown in FIG. 11, let the phase change value of the data symbol of (Carrier 1, Time $5) be "e j×δ15(i) ", the phase change value of the data symbol of (Carrier 2, Time $5) be "e j×δ25(i) ", the phase change value of the data symbol of (Carrier 3, Time $5) be "e j×δ35(i) ", the phase change value of the data symbol of (Carrier 4, Time $5) be "e j×δ45(i) ", the phase change value of the data symbol of (Carrier 5, Time $5) be "e j×δ55(i) ", the phase change value of the data symbol of (Carrier 1, Time $6) be "e j×δ16(i) ", the phase change value of the data symbol of (Carrier 2, Time $6) be "e j×δ26(i) ", the phase change value of the data symbol of (Carrier 4, Time $6) be "e j×δ46(i) ", and the phase change value of the data symbol of (Carrier 5, Time $6) be "e j×δ56(i) ".

[0114] On the other hand, in the symbols shown in FIG. 11, the other symbols of (Carrier 1, Time $4), (Carrier 2, Time $4), (Carrier 3, Time $4), (Carrier 4, Time $4), (Carrier 5, Time $4), and the pilot symbol of (Carrier 3, Time $6) are not the targets of the phase change by the phase change unit 205B.

[0115] This is a distinctive feature of the phase shifting unit 205B. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205B.)

[0116] As an example of the phase shifting applied to data symbols by the phase shifting unit 205B, one method is to apply a regular phase shift (with a phase shift period N) to the data symbols, as shown in equation (2). (However, this is not the only method of phase shifting applied to data symbols.)

[0117] This approach improves the data reception quality in receiving devices for MIMO-transmitted data symbols (transmitting multiple streams) in environments where direct waves are dominant, particularly in LOS (Line of Sight) environments. This effect will be explained below.

[0118] For example, assume that the modulation method used in the mapping unit 104 of FIG. 1 is QPSK (Quadrature Phase Shift Keying). (The signal 201A after mapping in FIG. 2 is a QPSK signal, and the signal 201B after mapping is also a QPSK signal. That is, two QPSK streams will be transmitted.) Then, in the signal processing unit 811 of FIG. 8, for example, 16 candidate signal points will be obtained using the channel estimation signals 806_1 and 806_2. (QPSK can transmit 2 bits, and with 2 streams, a total of 4 bits will be transmitted. Therefore, 2 4 = 16 candidate signal points exist) (Note that another 16 candidate signal points can be obtained using the channel estimation signals 808_1 and 808_2, but since the explanation is the same, the focus will be on the 16 candidate signal points obtained using the channel estimation signals 806_1 and 806_2, and the explanation will proceed.)

[0119] An example of the state at this time is shown in FIG. 12. In both FIG. 12(A) and FIG. 12(B), the horizontal axis is the in-phase I and the vertical axis is the quadrature Q. In the in-phase I - quadrature Q plane, 16 candidate signal points will exist. (One of the 16 candidate signal points is the signal point transmitted by the transmitting device. Therefore, it is called "16 candidate signal points".)

[0120] In an environment where the direct wave is dominant, especially in a LOS environment, Case 1: Consider the case where the phase change unit 205B in FIG. 2 does not exist (that is, when the phase change by the phase change unit 205B in FIG. 2 is not performed). Let's think about it.

[0121] In the case of "Case 1", since no phase change is performed, there is a possibility of falling into a state like FIG. 12(A). If it falls into the state of FIG. 12(A), there are parts where the signal points are dense (the distance between signal points is close), such as "signal points 1201 and 1202", "signal points 1203, 1204, 1205, 1206", "signal points 1207, 1208". Therefore, in the receiving device of FIG. 8, the reception quality of the data may deteriorate.

[0122] To overcome this problem, in FIG. 2, a phase change unit 205B is inserted. When the phase change unit 205B is inserted, depending on the symbol number i, there will be a mixture of symbol numbers where the signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and symbol numbers where "the distance between signal points is long" as shown in FIG. 12(B). For this state, since an error correction code is introduced, a high error correction capability can be obtained, and in the receiver of FIG. 8, high data reception quality can be obtained.

[0123] In FIG. 2, for "pilot symbols, preambles", etc. that are used for channel estimation to demodulate (detect) data symbols, no phase change is performed in the phase change unit 205B of FIG. 2. As a result, in the data symbols, "depending on the symbol number i, there is a mixture of symbol numbers where the signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and symbol numbers where 'the distance between signal points is long' as shown in FIG. 12(B)" can be realized.

[0124] However, even if the phase shift is applied in the phase shifting unit 205B in Figure 2 to the "pilot symbol and preamble," which are used for demodulating (detecting) data symbols and for channel estimation, it may still be possible to achieve a situation where, in the data symbols, "symbol number i contains both symbol numbers where signal points are densely packed (close distance between signal points) as shown in Figure 12(A) and symbol numbers where signal points are far apart as shown in Figure 12(B)." In this case, some condition must be added to the pilot symbol and preamble when performing the phase shift. For example, one could establish a separate rule from the phase shifting rule for data symbols and "apply phase shifting to the pilot symbol and / or preamble." As an example, one could apply a regular phase shift with period N to the data symbols and a regular phase shift with period M to the pilot symbol and / or preamble. (N and M are integers greater than or equal to 2.)

[0125] As previously mentioned, the phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, performs a phase shift on the baseband signal 208B based on the control signal 200, and outputs the phase-shifted signal 210B. Let the baseband signal 208B be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. The operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Literature 2 and Non-Patent Literature 3. A characteristic of the phase shifting unit 209B is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), etc.). (In the case of Figure 2, since the phase shifting unit 209B applies phase shifting to the baseband signal 208B, it will apply phase shifting to each symbol shown in Figure 5. If phase shifting is applied to the baseband signal 208A in Figure 2, it will apply phase shifting to each symbol shown in Figure 4. This point will be explained later.)

[0126] Therefore, in the frame of Figure 5, the phase shifting unit 209B in Figure 2 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503).

[0127] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift." ...

[0128] Figure 13 shows a different frame configuration for the transmitted signal 108_A in Figure 1 compared to Figure 4. In Figure 13, components that operate similarly to those in Figure 4 are given the same numbers. In Figure 13, the horizontal axis represents frequency (carrier), and the vertical axis represents time. As with Figure 4, a multi-carrier transmission method such as OFDM is used, so symbols exist in the carrier direction. And, as with Figure 4, Figure 13 shows the symbols for carriers 1 to 36. Also, as with Figure 4, Figure 13 shows the symbols for time $1 to time $11.

[0129] In Figure 13, in addition to the pilot symbol 401 (corresponding to the pilot signal 251A (pa(t)) in Figure 2), the data symbol 402, and other symbols 403, a null symbol 1301 is inserted.

[0130] The null symbol 1301 is defined as having a zero (0) in-phase component I and a zero (0) orthogonal component Q. (Note that while we refer to it as a "null symbol" here, this is not the only way to refer to it.)

[0131] In Figure 13, a null symbol is inserted into carrier 19. (Note that the method of inserting a null symbol is not limited to the configuration shown in Figure 13. For example, a null symbol may be inserted at a specific time, at a specific frequency and time domain, continuously in the time-frequency domain, or discretely in the time-frequency domain.)

[0132] Figure 14 shows a different frame configuration for the transmitted signal 108_B in Figure 1 compared to Figure 5. In Figure 14, components that operate similarly to those in Figure 5 are given the same numbers. In Figure 14, the horizontal axis represents frequency (carrier), and the vertical axis represents time. Similar to Figure 5, a multi-carrier transmission method such as OFDM is used, so symbols exist in the carrier direction. And, similar to Figure 5, Figure 14 shows the symbols for carriers 1 to 36. Also, similar to Figure 5, Figure 14 shows the symbols for time $1 to time $11.

[0133] In Figure 14, in addition to the pilot symbol 501 (corresponding to the pilot signal 251B (pb(t)) in Figure 2), the data symbol 502, and other symbols 503, a null symbol 1301 is inserted.

[0134] The null symbol 1301 is defined as having a zero (0) in-phase component I and a zero (0) orthogonal component Q. (Note that while we refer to it as a "null symbol" here, this is not the only way to refer to it.)

[0135] In Figure 14, a null symbol is inserted into carrier 19. (Note that the method of inserting a null symbol is not limited to the configuration shown in Figure 14. For example, a null symbol may be inserted at a specific time, at a specific frequency and time domain, continuously in the time-frequency domain, or discretely in the time-frequency domain.)

[0136] When a symbol exists on carrier A at time $B in Figure 13, and a symbol exists on carrier A at time $B in Figure 14, the symbols on carrier A at time $B in Figure 13 and the symbols on carrier A at time $B in Figure 14 will be transmitted at the same time and on the same frequency. Note that the frame configurations in Figures 13 and 14 are merely examples.

[0137] Furthermore, the other symbols in Figures 13 and 14 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 14 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 13, then it will be transmitting the same data (same control information).

[0138] Although it is assumed that the receiving device will receive the frames in Figure 13 and Figure 14 simultaneously, the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 13 or only the frames in Figure 14.

[0139] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i) (where j is the imaginary unit). Furthermore, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 2, the phase shifting unit 209B performs phase shifting on the baseband signal 208B, so it will perform phase shifting on each symbol shown in Figure 14. When performing phase shifting on the baseband signal 208A in Figure 2, it will perform phase shifting on each symbol shown in Figure 13. This point will be explained later.)

[0140] Therefore, in the frame of FIG. 14, for all symbols from carrier 1 to carrier 36 at time $1$ (in this case, all become other symbol 503), the phase change unit 209B in FIG. 2 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before.

[0141] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2$ (in this case, all become other symbol 503), the phase change unit 209B in FIG. 2 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." "For all symbols from carrier 1 to carrier 36 at time $3$ (in this case, all become other symbol 503), the phase change unit 209B in FIG. 2 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." "For all symbols from carrier 1 to carrier 36 at time $4$ (in this case, all become other symbol 503), the phase change unit 209B in FIG. 2 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." "For all symbols from carrier 1 to carrier 36 at time $5$ (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." "For all symbols from carrier 1 to carrier 36 at time $6$ (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 applies a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 applies a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 applies a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 applies a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 2 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0142] Let Ω(i) represent the phase change value in the phase change section 209B. The baseband signal 208B is x'(i), and the signal 210B after phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds true.

[0143] For example, set the phase change value as follows: (Q is an integer greater than or equal to 2, and Q is the period of the phase change.)

[0144]

number

[0145] For example, Ω(i) may be set to perform a phase change so that it has a period Q.

[0146] Alternatively, for example, in Figures 5 and 14, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. • For carrier 1 in Figures 5 and 14, regardless of time, the phase change value

number

number

number

number

[0147] The above is an example of the operation of the phase shifting unit 209B shown in Figure 2.

[0148] The effects obtained by the phase shifting unit 209B in Figure 2 will be explained.

[0149] The other symbols 403 and 503 in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, are assumed to contain control information symbols. As previously explained, the other symbols 503 in Figure 5, at the same time and on the same frequency (same carrier) as the other symbols 403, transmit the same data (same control information) when transmitting control information.

[0150] Now, consider the following case.

[0151] Case 2: The control information symbol is transmitted using either antenna unit #A (109_A) or antenna unit #B (109_B) shown in Figure 1.

[0152] In the case of transmission as in "Case 2," since only one antenna transmits the control information symbols, the spatial diversity gain is smaller compared to the case where "both antenna unit #A (109_A) and antenna unit #B (109_B) are used to transmit the control information symbols." Therefore, in "Case 2," the data reception quality will be reduced even when received by the receiver in Figure 8. Consequently, in terms of improving data reception quality, it is better to "transmit the control information symbols using both antenna unit #A (109_A) and antenna unit #B (109_B)."

[0153] Case 3: The control information symbol is transmitted using both antenna section #A (109_A) and antenna section #B (109_B) in Figure 1. However, no phase shifting is performed in the phase shifting section 209B in Figure 2.

[0154] In the case of transmission as in "Case 3," the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are identical (or have a specific phase difference). Therefore, depending on the radio wave propagation environment, the receiver in Figure 8 may receive a very poor signal, and both modulated signals may be affected by the same multipath. As a result, the receiver in Figure 8 faces the problem of reduced data reception quality.

[0155] To mitigate this issue, a phase shifting unit 209B is provided in Figure 2. This changes the phase in the time or frequency direction, thus reducing the possibility of a poor received signal in the receiver shown in Figure 8. Furthermore, since there is a high probability that the multipath effects on the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are different, diversity gain is likely to be obtained, which improves the data reception quality in the receiver shown in Figure 8.

[0156] For the reasons stated above, a phase shifting unit 209B is provided in Figure 2 to perform phase shifting.

[0157] Other symbols 403 and 503 include, in addition to control information symbols, symbols for signal detection, symbols for frequency and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) for demodulating and decoding control information symbols. Furthermore, the frames in Figures 4 and 5, or Figures 13 and 14, include pilot symbols 401 and 501, which can be used to demodulate and decode control information symbols with higher accuracy.

[0158] Furthermore, in the frames of Figures 4 and 5, or Figures 13 and 14, multiple streams are transmitted using the same frequency (band) and time using data symbols 402 and 502 (MIMO transmission is performed). In order to demodulate these data symbols, other symbols 403 and other symbols 503, which are included in the other symbols, are used for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variations).

[0159] At this time, the "other symbols 403 and other symbols 503, which include symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations)," undergo phase shifting by the phase shifting unit 209B, as previously mentioned.

[0160] In such circumstances, if this process is not applied to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 502), the receiving device will need to perform demodulation and decoding that reflects the phase change processing performed by the phase change unit 209B when demodulating and decoding data symbol 402 and data symbol 502, and this process is likely to become complex. (This is because the phase change is performed by the phase change unit 209B on "other symbols 403 and other symbols 503, including symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations).")

[0161] However, as shown in Figure 2, when the phase shifting unit 209B applies a phase shift to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 502), the receiving device has the advantage of being able to (easily) demodulate and decode data symbol 402 and data symbol 502 using the channel estimation signal (propagation path variation estimation signal) estimated using "other symbols 403 and other symbols 503, which are included in the other symbols for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variation)".

[0162] In addition, as shown in Figure 2, when the phase shifting unit 209B applies phase shifting to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 502), the effect of abrupt drops in electric field strength on the frequency axis in multipath can be reduced, which may result in an improvement in the reception quality of data for data symbol 402 and data symbol 502.

[0163] Thus, a distinctive feature is that the "target symbols to which the phase change unit 205B applies the phase change" and the "target symbols to which the phase change unit 209B applies the phase change" are different.

[0164] As described above, by performing a phase change using the phase change unit 205B in Figure 2, it is possible to improve the data reception quality of data symbols 402 and 502, especially in an LOS environment, and by performing a phase change using the phase change unit 209B in Figure 2, it is possible to improve the reception quality of control information symbols included in, for example, "frames in Figures 4 and 5" or "frames in Figures 13 and 14" in the receiving device, and to simplify the demodulation and decoding operations of data symbols 402 and 502.

[0165] Furthermore, by performing a phase change using the phase change unit 205B in Figure 2, the reception quality of data symbols 402 and 502 in the receiving device is improved, especially in an LOS environment. Additionally, by performing a phase change on data symbols 402 and 502 using the phase change unit 209B in Figure 2, the reception quality of data symbols 402 and 502 is further improved.

[0166] In Figure 2, the phase shifting unit 209B is provided after the insertion unit 207B, illustrating a configuration in which the phase shifting unit 208B is applied to the baseband signal 208B. However, the configuration for obtaining both the phase shifting effect of the phase shifting unit 205B and the phase shifting effect of the phase shifting unit 209B is not limited to the configuration shown in Figure 2. For example, a modified configuration in which the phase shifting unit 209B is removed from the configuration in Figure 2, the baseband signal 208B output from the insertion unit 207B is used as the signal after signal processing 106_B, and a phase shifting unit 209A that operates similarly to the phase shifting unit 209B is added after the insertion unit 207A, and the phase-shifted signal 210A, obtained by the phase shifting unit 209A on the baseband signal 208A, is used as the signal after signal processing 106_A. Even with this configuration, as in the case of Figure 2 described above, by performing a phase change with the phase change unit 205B, it is possible to obtain the effect of improving the data reception quality of data symbols 402 and 502, especially in an LOS environment, at the receiving device. Furthermore, by performing a phase change with respect to data symbols 402 and 502 using the phase change unit 209A, it is possible to obtain the effect of improving the reception quality of data symbols 402 and 502.

[0167] Furthermore, it is possible to obtain the effect of improving the reception quality of the control information symbols contained in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, in the receiving device.

[0168] (Supplement 1) In Embodiment 1 and other examples, it was stated that the operation of the "phase shifting unit B" may be the CDD (CSD) described in Non-Patent Documents 2 and 3. Further explanation is provided regarding this point.

[0169] Figure 15 shows the configuration when using CDD (CSD). 1501 is the modulated signal without cyclic delay, and is represented as X[n].

[0170] The cyclic delay section 1502_1 receives the modulated signal 1501 as input, performs cyclic delay processing, and outputs the signal 1503_1 after cyclic delay processing. If the signal 1503_1 after cyclic delay processing is X1[n], then X1[n] is given by the following equation.

[0171]

number

[0172] Note that δ1 is the cyclic delay (δ1 is a real number), X[n] consists of N symbols (N is an integer greater than or equal to 2), and therefore n is an integer between 0 and N-1. ...

[0173] The cyclic delay section 1502_M receives the modulated signal 1501 as input, performs cyclic delay processing, and outputs the signal 1503_M after cyclic delay processing. If the signal 1503_M after cyclic delay processing is XM[n], then XM[n] is given by the following equation.

[0174]

number

[0175] Note that δM is the cyclic delay (δM is a real number), X[n] consists of N symbols (N is an integer greater than or equal to 2), and therefore n is an integer between 0 and N-1.

[0176] Therefore, the cyclic delay section 1502_i (where i is an integer between 1 and M (M is an integer greater than or equal to 1)) takes the modulated signal 1501 as input, performs cyclic delay processing, and outputs the signal 1503_i after cyclic delay processing. If the signal 1503_i after cyclic delay processing is Xi[n], then Xi[n] is given by the following equation.

[0177]

number

[0178] Note that δi is the cyclic delay (δi is a real number), X[n] consists of N symbols (N is an integer greater than or equal to 2), and therefore n is an integer between 0 and N-1.

[0179] Then, signal 1503_i, after cyclic delay processing, will be transmitted from antenna i. (Therefore, signals 1503_1, ..., and 1503_M, after cyclic delay processing, will each be transmitted from different antennas.)

[0180] By doing so, a diversity effect can be obtained through cyclic delay (in particular, the adverse effects of delayed waves can be reduced), resulting in improved data reception quality in the receiving device.

[0181] For example, the phase shifting unit 209B in Figure 2 may be replaced with the cyclic delay unit shown in Figure 15, and the operation of the phase shifting unit 209B may be made to be the same as that of the cyclic delay unit.

[0182] Therefore, in the phase shifting unit 209B of Figure 2, a cyclic delay amount δ (where δ is a real number) is given, and the input signal of the phase shifting unit 209B is represented as Y[n]. Then, when the output signal of the phase shifting unit 209B is represented as Z[n], Z[n] is given by the following equation.

[0183]

number

[0184] Y[n] is composed of N symbols (where N is an integer greater than or equal to 2), and therefore, n is an integer between 0 and N-1 (inclusive).

[0185] Next, we will explain the relationship between cyclic delay and phase shift.

[0186] For example, consider the case where CDD (CSD) is applied to OFDM. The carrier configuration when using OFDM will be as shown in Figure 16.

[0187] In Figure 16, 1601 is a symbol, and the horizontal axis represents frequency (carrier number), with carriers arranged in ascending order from lowest to highest frequency. Therefore, if the lowest frequency carrier is designated as "Carrier 1," then "Carrier 2," "Carrier 3," "Carrier 4," and so on, are assumed to follow.

[0188] For example, let's assume that a cyclic delay amount τ is given in the phase shifting unit 209B in Figure 2. Then, the phase shifting value Ω[i] in "carrier i" can be expressed as follows.

[0189]

number

[0190] Note that μ is a value that can be determined from the cyclic delay amount, the FFT (Fast Fourier Transform) size, etc.

[0191] Then, if we denote the baseband signal v'[i][t] as "carrier i" before the phase change (before cyclic delay processing), the signal v[i][t] at time t, "carrier i" after the phase change, can be expressed as v[i][t]=Ω[i]×v'[i][t].

[0192] (Supplement 2) Naturally, multiple embodiments and other elements described herein may be combined and implemented.

[0193] Furthermore, each embodiment and other details are merely examples. For example, even if "modulation method, error correction coding method (error correction code used, code length, coding rate, etc.), control information, etc." are given as examples, it is possible to implement the same configuration even if a different "modulation method, error correction coding method (error correction code used, code length, coding rate, etc.), control information, etc." is applied.

[0194] Regarding the modulation scheme, it is possible to implement the embodiments and other details described herein even if a modulation scheme other than those described herein is used. For example, APSK (Amplitude Phase Shift Keying) (e.g., 16APSK, 64APSK, 128APSK, 256APSK, 1024APSK, 4096APSK, etc.), PAM (Pulse Amplitude Modulation) (e.g., 4PAM, 8PAM, 16PAM, 64PAM, 128PAM, 256PAM, 1024PAM, 4096PAM, etc.), PSK (Phase Shift Keying) (e.g., BPSK, QPSK, 8PSK, 16PSK, 64PSK, 128PSK, 256PSK, 1024PSK, 4096PSK, etc.), QAM (Quadrature Amplitude Modulation) (e.g., 4QAM, 8QAM, 16QAM, 64QAM, 128QAM, You may apply 256QAM, 1024QAM, 4096QAM, etc., and in each modulation scheme, you may use uniform mapping or non-uniform mapping.

[0195] Furthermore, the arrangement of signal points such as 2, 4, 8, 16, 64, 128, 256, and 1024 in the IQ plane (modulation schemes having 2, 4, 8, 16, 64, 128, 256, and 1024 signal points) is not limited to the signal point arrangement methods of the modulation schemes shown herein. Therefore, the function of outputting common-mode and quadrature components based on multiple bits becomes the function of the mapping unit, and then applying precoding and phase shifting is one of the effective functions of the present invention.

[0196] In this specification, when "∀" and "∃" are present, "∀" represents a universal quantifier, and "∃" represents an existential quantifier.

[0197] Furthermore, in this specification, when a complex plane is present, the unit of phase, such as the argument angle, is defined as "radian."

[0198] Using the complex plane, complex numbers can be expressed in polar form using polar coordinates. When a complex number z = a + jb (where a and b are real numbers and j is the imaginary unit) is associated with a point (a, b) on the complex plane, if this point is represented as [r, θ] in polar coordinates, then a = r × cosθ and b = r × sinθ.

number

[0199] In this specification, the terminal's receiving device and antenna may be configured to be separate. For example, the receiving device may have an interface that receives the signal received by the antenna, or a signal obtained by frequency conversion of the signal received by the antenna, through a cable, and the receiving device will then perform the subsequent processing.

[0200] Furthermore, the data and information obtained by the receiving device are subsequently converted into video and audio and displayed on a display (monitor) or output as sound from speakers. In addition, the data and information obtained by the receiving device may undergo signal processing related to video and audio (or not), and may be output from RCA terminals (video terminals, audio terminals), USB (Universal Serial Bus), HDMI (registered trademark) (High-Definition Multimedia Interface), digital terminals, etc., provided by the receiving device.

[0201] In this specification, a transmitting device may be, for example, a communication / broadcasting device such as a broadcasting station, base station, access point, terminal, or mobile phone, and a receiving device may be a communication device such as a television, radio, terminal, personal computer, mobile phone, access point, or base station. Furthermore, the transmitting device and receiving device in this invention may be devices having a communication function, and such devices may be configured to be connected via some interface to a device for running applications such as a television, radio, personal computer, or mobile phone.

[0202] Furthermore, in this embodiment, symbols other than data symbols, such as pilot symbols (preamble, unique word, postamble, reference symbol, etc.) and symbols for control information, may be arranged in any way within the frame. While we refer to them here as pilot symbols and symbols for control information, any naming convention is acceptable, as the function itself is what matters.

[0203] The pilot symbol can be any known symbol modulated using PSK modulation in the transceiver (or the receiver may know the symbol transmitted by the transmitter by synchronizing with it). The receiver will use this symbol to perform frequency synchronization, time synchronization, channel estimation (CSI (Channel State Information) estimation) (for each modulated signal), signal detection, etc.

[0204] Furthermore, symbols for control information are used to transmit information that needs to be sent to the communication partner in order to enable communication other than data (such as applications), such as the modulation scheme, error correction coding scheme, coding rate of the error correction coding scheme, and settings information at higher layers.

[0205] It should be noted that the present invention is not limited to the embodiments described, and can be implemented with various modifications. For example, although each embodiment describes the case where the communication is performed as a communication device, it is not limited to this, and this communication method can also be performed as software.

[0206] Furthermore, while the above describes a precoding switching method for transmitting two modulated signals from two antennas, it is not limited to this method. In other words, the same precoding switching method can be implemented by changing the precoding weight (matrix) in a method where precoding is performed on four mapped signals to generate four modulated signals and transmit them from four antennas, or in a method where precoding is performed on N mapped signals to generate N modulated signals and transmit them from N antennas.

[0207] In this specification, terms such as "precoding" and "precoding weight" are used, but the terminology itself can be anything; in this invention, the signal processing itself is what is important.

[0208] Streams s1(t) and s2(t) may transmit different data or the same data.

[0209] Both the transmitting antenna of the transmitting device and the receiving antenna of the receiving device, as shown in the drawings, may be composed of multiple antennas.

[0210] The transmitting device communicates to the receiving device: The transmission method (MIMO, SISO, spatiotemporal block coding, interleaved scheme), modulation scheme, and error correction coding scheme must be notified. Depending on the embodiment, it may be omitted. The frame that the transmitting device will be present in The receiving device will change its operation upon receiving this information.

[0211] Alternatively, for example, a program that performs the above communication method may be stored in ROM (Read Only Memory) beforehand, and that program may be run by the CPU (Central Processor Unit).

[0212] Alternatively, a program that performs the above communication method may be stored in a computer-readable storage medium, and the program stored in the storage medium may be recorded in the computer's RAM (Random Access Memory) so that the computer operates according to that program.

[0213] Each of the above embodiments and configurations may be implemented as a Large Scale Integration (LSI), which is typically an integrated circuit. These may be individually integrated onto a single chip, or they may be integrated onto a single chip that includes all or some of the configurations of each embodiment. Here, we refer to them as LSIs, but depending on the degree of integration, they may also be called ICs (Integrated Circuits), system LSIs, super LSIs, or ultra LSIs. Furthermore, the method of integrated circuit implementation is not limited to LSIs; it may also be implemented using dedicated circuits or general-purpose processors. After LSI manufacturing, FPGAs (Field Programmable Gate Arrays) that can be programmed or reconfigurable processors that allow for the reconfiguration of the connections and settings of circuit cells inside the LSI may also be used.

[0214] Furthermore, if advancements in semiconductor technology or related technologies lead to the emergence of integrated circuit technologies that replace LSIs, then naturally, it would be acceptable to use those technologies to integrate functional blocks. The application of biotechnology, for example, is a possible possibility.

[0215] The present invention can be broadly applied to wireless systems that transmit different modulated signals from multiple antennas. It can also be applied to wired communication systems with multiple transmission points (e.g., PLC (Power Line Communication) systems, optical communication systems, DSL (Digital Subscriber Line) systems) when MIMO transmission is performed.

[0216] (Embodiment 2) In this embodiment, a method for implementing a configuration different from that shown in Figure 2 of Embodiment 1 will be described.

[0217] Figure 1 shows an example of the configuration of a transmitting device such as a base station, access point, or broadcasting station in this embodiment. Details have been explained in Embodiment 1, so a further explanation will be omitted here.

[0218] The signal processing unit 106 receives the mapped signals 105_1 and 105_2, the signal group 110, and the control signal 100 as inputs, performs signal processing based on the control signal 100, and outputs the processed signals 106_A and 106_B. In this case, the processed signal 106_A is represented as u1(i) and the processed signal 106_B is represented as u2(i) (where i is a symbol number, for example, i is a non-negative integer). Details of the signal processing will be explained using Figure 18.

[0219] Figure 18 shows an example of the configuration of the signal processing unit 106 in Figure 1. The weighted synthesis unit (precoding unit) 203 takes the mapped signal 201A (corresponding to the mapped signal 105_1 in Figure 1), the mapped signal 201B (corresponding to the mapped signal 105_2 in Figure 1), and the control signal 200 (corresponding to the control signal 100 in Figure 1) as inputs, performs manual weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, the mapped signal 201A is represented as s1(t), the mapped signal 201B as s2(t), the weighted signal 204A as z1(t), and the weighted signal 204B as z2'(t). Hereinafter, t is taken as time. (Let s1(t), s2(t), z1(t), and z2'(t) be defined as complex numbers. (Therefore, they may also be real numbers.)) Here, it is treated as a function of time, but it may also be treated as a function of "frequency (carrier number)" or as a function of "time·frequency". It may also be treated as a function of "symbol number". This point is the same in Embodiment 1.

[0220] The weighted composition unit (precoding unit) 203 will perform the calculation in equation (1).

[0221] The phase shifting unit 205B receives the weighted combined signal 204B and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204B and outputs the phase-shifted signal 206B. The phase-shifted signal 206B is denoted as z2(t), and z2(t) is defined as a complex number. (It may also be a real number.)

[0222] The specific operation of the phase shifting unit 205B will now be explained. For example, the phase shifting unit 205B applies a phase shift of y(i) to z2'(i). Therefore, z2(i) can be expressed as z2(i) = y(i) × z2'(i). (i is the symbol number; i is a non-negative integer.)

[0223] For example, the phase change value can be set as shown in equation (2). (N is an integer greater than or equal to 2, and N is the phase change period.) (Setting N to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (2) is merely an example and is not the only option. Therefore, the phase change value y(i) = e j×δ(i) It shall be represented as follows.

[0224] In this case, z1(i) and z2(i) can be expressed by equation (3), where δ(i) is a real number. Furthermore, z1(i) and z2(i) are transmitted from the transmitting device at the same time and frequency (same frequency band). In equation (3), the phase change value is not limited to that given in equation (2); for example, a method of periodically and regularly changing the phase can be considered.

[0225] As explained in Embodiment 1, the (precoding) matrices in equations (1) and (3) can be those from equations (5) to (36), etc. (However, the precoding matrices are not limited to these. (The same applies to Embodiment 1.))

[0226] The insertion unit 207A receives the weighted combined signal 204A, the pilot symbol signal (pa(t)) (t: time) (251A), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208A based on the frame configuration information contained in the control signal 200.

[0227] Similarly, the insertion unit 207B receives the phase-shifted signal 206B, the pilot symbol signal (pb(t))(251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208B based on the frame configuration information contained in the control signal 200.

[0228] The phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. Let the baseband signal 208A be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i), where j is the imaginary unit.

[0229] As described in Embodiment 1 and other documents, the operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209A is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0230] Figure 3 shows an example of the configuration of the wireless units 107_A and 107_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0231] Figure 4 shows the frame configuration of the transmission signal 108_A in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0232] Figure 5 shows the frame configuration of the transmitted signal 108_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0233] When a symbol exists on carrier A at time $B in Figure 4, and a symbol exists on carrier A at time $B in Figure 5, the symbols on carrier A at time $B in Figure 4 and the symbols on carrier A at time $B in Figure 5 will be transmitted at the same time and on the same frequency. Note that the frame configuration is not limited to Figures 4 and 5; Figures 4 and 5 are merely examples of frame configurations.

[0234] Furthermore, the other symbols in Figures 4 and 5 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 5 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 4, then it will be transmitting the same data (same control information).

[0235] It is assumed that the receiving device will receive the frames in Figure 4 and Figure 5 simultaneously, but the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 4 or only the frames in Figure 5.

[0236] Figure 6 shows an example of the configuration of the control information generation part for generating the control information signal 253 in Figure 2. Since a detailed explanation was given in Embodiment 1, the explanation will be omitted here.

[0237] Figure 7 shows an example of the configuration of antenna section #A (109_A) and antenna section #B (109_B) in Figure 1 (an example in which antenna section #A (109_A) and antenna section #B (109_B) are composed of multiple antennas). A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0238] Figure 8 shows an example of the configuration of a receiving device that receives a modulated signal when the transmitting device in Figure 1 transmits a transmission signal with the frame configuration shown in Figures 4 and 5, for example. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0239] Figure 10 shows an example of the configuration of antenna section #X (801X) and antenna section #Y (801Y) in Figure 8. (This is an example where antenna section #X (801X) and antenna section #Y (801Y) are composed of multiple antennas.) As Figure 10 was explained in detail in Embodiment 1, its explanation will be omitted here.

[0240] Next, as shown in Figure 1, the signal processing unit 106 of the transmitting device has phase shifting units 205B and 209A inserted, as shown in Figure 18. Its features and effects will be explained below.

[0241] As explained using Figures 4 and 5, the phase shifting unit 205B performs precoding (weighted synthesis) on the mapped signal s1(i)(201A) (where i is the symbol number and i is a non-negative integer) obtained by mapping using the first sequence and the mapped signal s2(i)(201B) obtained by mapping using the second sequence, and then performs a phase shift on one of the resulting weighted synthesized signals 204A and 204B. The weighted synthesized signal 204A and the phase-shifted signal 206B are then transmitted at the same frequency and at the same time. Therefore, in Figures 4 and 5, the phase shift is applied to the data symbol 502 in Figure 5. (In the case of Figure 18, the phase shifting unit 205 is applied to the weighted combined signal 204B, so the phase shift is applied to the data symbol 502 in Figure 5. If the phase shift is applied to the weighted combined signal 204A, the phase shift will be applied to the data symbol 402 in Figure 4. This point will be explained later.)

[0242] For example, Figure 11 shows the frame from Figure 5 with carriers 1 through 5 and time points $4 through $6 extracted. As with Figure 5, 501 is the pilot symbol, 502 is the data symbol, and 503 is the other symbol.

[0243] As described above, in the symbols shown in Figure 11, the phase change unit 205B will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0244] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×δ15(i) " and the phase change value of the data symbol (carrier 2, time $5) is "e j×δ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×δ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×δ45(i) " and the phase change value of the data symbol (carrier 5, time $5) is "e j×δ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×δ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×δ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×δ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×δ56(i) "

[0245] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205B.

[0246] This is a distinctive feature of the phase shifting unit 205B. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205B.)

[0247] As an example of the phase shifting applied to data symbols by the phase shifting unit 205B, one method is to apply a regular phase shift (with a phase shift period N) to the data symbols, as shown in equation (2). (However, this is not the only method of phase shifting applied to data symbols.)

[0248] This approach improves the data reception quality in receiving devices for MIMO-transmitted data symbols (transmitting multiple streams) in environments where direct waves are dominant, particularly in LOS (Line of Sight) environments. This effect will be explained below.

[0249] For example, let's assume that the modulation scheme used in the mapping unit 104 in Figure 1 is QPSK (Quadrature Phase Shift Keying). (The mapped signal 201A in Figure 18 is a QPSK signal, and the mapped signal 201B is also a QPSK signal. In other words, two QPSK streams will be transmitted.) Then, in the signal processing unit 811 in Figure 8, for example, channel estimation signals 806_1 and 806_2 will be used to obtain 16 candidate signal points. (QPSK can transmit 2 bits, and with 2 streams, a total of 4 bits will be transmitted. Therefore, 2 4 (There are 16 candidate signal points.) (Note that another 16 candidate signal points can be obtained using channel estimation signals 808_1 and 808_2, but the explanation will be the same. Therefore, we will focus on and explain the 16 candidate signal points obtained using channel estimation signals 806_1 and 806_2.)

[0250] An example of this state is shown in Figure 12. In both Figure 12(A) and Figure 12(B), the horizontal axis represents the in-phase I and the vertical axis represents the orthogonal Q. In the in-phase I-orthogonal Q plane, there are 16 candidate signal points. (Of these 16 candidate signal points, one is the signal point transmitted by the transmitting device. This is why they are called "16 candidate signal points.")

[0251] In environments where direct waves are dominant, especially in LOS environments, Case 1: If the phase shifting unit 205B in Figure 18 does not exist (i.e., if the phase shifting unit 205B in Figure 18 is not performed) Let's consider this.

[0252] In the "first case," since no phase change is performed, it is possible to fall into a state like that shown in Figure 12(A). If the state shown in Figure 12(A) occurs, there are areas where the signal points are densely packed (closely separated), such as "signal points 1201 and 1202," "signal points 1203, 1204, 1205, and 1206," and "signal points 1207 and 1208," which may cause a decrease in the data reception quality in the receiving device shown in Figure 8.

[0253] To overcome this challenge, a phase shifting unit 205B is inserted in Figure 18. When the phase shifting unit 205B is inserted, symbol numbers i will have a mix of symbol numbers where the signal points are dense (close distance between signal points), as shown in Figure 12(A), and symbol numbers where the signal points are far apart, as shown in Figure 12(B). By introducing an error correction code to address this situation, a high error correction capability can be obtained, resulting in high data reception quality in the receiving device shown in Figure 8.

[0254] Furthermore, in Figure 18, the phase shifting unit 205B in Figure 18 does not perform phase shifting on the "pilot symbol and preamble," which are used for channel estimation to demodulate (detect) data symbols. This makes it possible to achieve a situation in the data symbols where "symbol number i has a mix of symbol numbers where the signal points are dense (close distance between signal points) as in Figure 12(A) and symbol numbers where the signal points are far apart as in Figure 12(B)."

[0255] However, even if the phase shift is applied in the phase shifting unit 205B in Figure 18 to the "pilot symbol and preamble," which are used for channel estimation to demodulate (detect) data symbols, it may still be possible to achieve a situation where, in the data symbols, "symbol number i contains both symbol numbers where signal points are densely packed (close distance between signal points) as shown in Figure 12(A) and symbol numbers where signal points are far apart as shown in Figure 12(B)." In this case, some condition must be added to the pilot symbol and preamble when performing the phase shift. For example, one could establish a separate rule from the phase shifting rule for data symbols and "apply phase shifting to the pilot symbol and / or preamble." As an example, one could apply a phase shift with period N to the data symbols regularly and a phase shift with period M to the pilot symbol and / or preamble regularly. (N and M are integers greater than or equal to 2.)

[0256] As previously mentioned, the phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. Let the baseband signal 208A be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. The operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A characteristic of the phase shifting unit 209A is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), etc.). (In the case of Figure 18, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 4.)

[0257] Therefore, in the frame of Figure 4, the phase shifting unit 209A in Figure 18 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403).

[0258] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift." ...

[0259] Figure 13 shows a different frame configuration for the transmitted signal 108_A in Figure 1 compared to Figure 4. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0260] Figure 14 shows a different frame configuration for the transmitted signal 108_B in Figure 1 compared to Figure 5. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0261] When a symbol exists on carrier A at time $B in Figure 13, and a symbol exists on carrier A at time $B in Figure 14, the symbols on carrier A at time $B in Figure 13 and the symbols on carrier A at time $B in Figure 14 will be transmitted at the same time and on the same frequency. Note that the frame configurations in Figures 13 and 14 are merely examples.

[0262] Furthermore, the other symbols in Figures 13 and 14 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 18. Therefore, if the other symbol 503 in Figure 14 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 13, then it will be transmitting the same data (same control information).

[0263] Although it is assumed that the receiving device will receive the frames in Figure 13 and Figure 14 simultaneously, the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 13 or only the frames in Figure 14.

[0264] The phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. The baseband signal 208A is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. Furthermore, the operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209A is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 18, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 13.)

[0265] Therefore, in the frame of Figure 13, the phase shifting unit 209A in Figure 18 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0266] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 18 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0267] Let Ω(i) represent the phase change value in the phase change section 209A. The baseband signal 208A is x'(i), and the signal 210A after phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds true.

[0268] For example, set the phase change value to equation (38). (Q is an integer greater than or equal to 2, and Q is the period of the phase change.) (j is the imaginary unit) However, equation (38) is merely an example and is not the only one.

[0269] For example, Ω(i) may be set to perform a phase change so that it has a period Q.

[0270] Alternatively, as shown in Figures 4 and 13, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. • For carrier 1 in Figures 4 and 13, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 4 and 13, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 4 and 13, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 4 and 13, the phase change value is given by equation (42), regardless of time. ...

[0271] The above is an example of the operation of the phase shifting unit 209A shown in Figure 18.

[0272] The effects obtained by the phase shifting unit 209A in Figure 18 will be explained.

[0273] The other symbols 403 and 503 in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, are assumed to contain control information symbols. As previously explained, the other symbols 503 in Figure 5, at the same time and on the same frequency (same carrier) as the other symbols 403, transmit the same data (same control information) when transmitting control information.

[0274] Now, consider the following case.

[0275] Case 2: The control information symbol is transmitted using either antenna unit #A (109_A) or antenna unit #B (109_B) shown in Figure 1.

[0276] In the case of transmission as in "Case 2," since only one antenna transmits the control information symbols, the spatial diversity gain is smaller compared to the case where "both antenna unit #A (109_A) and antenna unit #B (109_B) are used to transmit the control information symbols." Therefore, in "Case 2," the data reception quality will be reduced even when received by the receiver in Figure 8. Consequently, in terms of improving data reception quality, it is better to "transmit the control information symbols using both antenna unit #A (109_A) and antenna unit #B (109_B)."

[0277] Case 3: The control information symbol is transmitted using both antenna section #A (109_A) and antenna section #B (109_B) in Figure 1. However, no phase shift is performed in the phase shift section 209A in Figure 18.

[0278] In the case of transmission as in "Case 3," the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are identical (or have a specific phase difference). Therefore, depending on the radio wave propagation environment, the receiver in Figure 8 may receive a very poor signal, and both modulated signals may be affected by the same multipath. As a result, the receiver in Figure 8 faces the problem of reduced data reception quality.

[0279] To mitigate this issue, a phase shifting unit 209A is provided in Figure 18. This changes the phase in the time or frequency direction, thereby reducing the possibility of a poor received signal in the receiver shown in Figure 8. Furthermore, since there is a high probability that the multipath effects on the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are different, diversity gain is likely to be obtained, which improves the data reception quality in the receiver shown in Figure 8.

[0280] For the reasons stated above, a phase shifting unit 209A is provided in Figure 18 to perform phase shifting.

[0281] Other symbols 403 and 503 include, in addition to control information symbols, symbols for signal detection, symbols for frequency and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) for demodulating and decoding control information symbols. Furthermore, the frames in Figures 4 and 5, or Figures 13 and 14, include pilot symbols 401 and 501, which can be used to demodulate and decode control information symbols with higher accuracy.

[0282] Furthermore, in the frames of Figures 4 and 5, or Figures 13 and 14, multiple streams are transmitted using the same frequency (band) and time using data symbols 402 and 502 (MIMO transmission is performed). In order to demodulate these data symbols, other symbols 403 and other symbols 503, which are included in the other symbols, are used for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variations).

[0283] At this time, the "other symbols 403 and other symbols 503, which include symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations)," undergo phase shifting by the phase shifting unit 209A, as previously mentioned.

[0284] In such circumstances, if this process is not applied to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 402), the receiving device will need to perform demodulation and decoding that reflects the phase change processing performed by the phase change unit 209A when demodulating and decoding data symbol 402 and data symbol 502, and this process is likely to become complex. (This is because the phase change is performed by the phase change unit 209A on "other symbols 403 and other symbols 503, which include symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations).")

[0285] However, as shown in Figure 18, when the phase shifting unit 209A applies a phase shift to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 402), the receiving device has the advantage of being able to (easily) demodulate and decode data symbol 402 and data symbol 502 using the channel estimation signal (propagation path variation estimation signal) estimated using "other symbols 403 and other symbols 503, which are included in the other symbols for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variation)".

[0286] In addition, as shown in Figure 18, when the phase shifting unit 209A applies phase shifting to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 402), the effect of abrupt drops in electric field strength on the frequency axis in multipath can be reduced, which may result in an improvement in the reception quality of data for data symbol 402 and data symbol 502.

[0287] Thus, a distinctive feature is that the "target symbols to which the phase change unit 205B applies the phase change" and the "target symbols to which the phase change unit 209A applies the phase change" are different.

[0288] As described above, by performing a phase change using the phase change unit 205B in Figure 18, it is possible to improve the data reception quality of data symbols 402 and 502, especially in an LOS environment, and by performing a phase change using the phase change unit 209A in Figure 18, it is possible to improve the reception quality of control information symbols included in, for example, "frames in Figures 4 and 5" or "frames in Figures 13 and 14," in the receiving device, and to simplify the demodulation and decoding operations of data symbols 402 and 502.

[0289] Furthermore, by performing a phase change using the phase change unit 205B in Figure 18, the reception quality of data symbols 402 and 502 in the receiving device is improved, especially in an LOS environment. Additionally, by performing a phase change on data symbols 402 and 502 using the phase change unit 209A in Figure 18, the reception quality of data symbols 402 and 502 is further improved.

[0290] Note that Q in equation (38) may be an integer less than or equal to -2, in which case the period of phase change will be the absolute value of Q. This point can also be applied to Embodiment 1.

[0291] (Embodiment 3) In this embodiment, a method for implementing a configuration different from that shown in Figure 2 of Embodiment 1 will be described.

[0292] Figure 1 shows an example of the configuration of a transmitting device such as a base station, access point, or broadcasting station in this embodiment. Details have been explained in Embodiment 1, so a further explanation will be omitted here.

[0293] The signal processing unit 106 receives the mapped signals 105_1 and 105_2, the signal group 110, and the control signal 100 as inputs, performs signal processing based on the control signal 100, and outputs the processed signals 106_A and 106_B. In this case, the processed signal 106_A is represented as u1(i) and the processed signal 106_B is represented as u2(i) (where i is a symbol number, for example, i is a non-negative integer). Details of the signal processing will be explained using Figure 19.

[0294] Figure 19 shows an example of the configuration of the signal processing unit 106 in Figure 1. The weighted synthesis unit (precoding unit) 203 takes the mapped signal 201A (corresponding to the mapped signal 105_1 in Figure 1), the mapped signal 201B (corresponding to the mapped signal 105_2 in Figure 1), and the control signal 200 (corresponding to the control signal 100 in Figure 1) as inputs, performs manual weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, the mapped signal 201A is represented as s1(t), the mapped signal 201B as s2(t), the weighted signal 204A as z1(t), and the weighted signal 204B as z2'(t). Hereinafter, t is taken as time. (Let s1(t), s2(t), z1(t), and z2'(t) be defined as complex numbers. (Therefore, they may also be real numbers.))

[0295] Here, it is treated as a function of time, but it may also be treated as a function of "frequency (carrier number)" or as a function of "time·frequency". It may also be treated as a function of "symbol number". This point is the same in Embodiment 1.

[0296] The weighted composition unit (precoding unit) 203 will perform the calculation in equation (1).

[0297] The phase shifting unit 205B receives the weighted combined signal 204B and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204B and outputs the phase-shifted signal 206B. The phase-shifted signal 206B is denoted as z2(t), and z2(t) is defined as a complex number. (It may also be a real number.)

[0298] The specific operation of the phase shifting unit 205B will now be explained. For example, the phase shifting unit 205B applies a phase shift of y(i) to z2'(i). Therefore, z2(i) can be expressed as z2(i) = y(i) × z2'(i). (i is the symbol number; i is a non-negative integer.)

[0299] For example, the phase change value can be set as shown in equation (2). (N is an integer greater than or equal to 2, and N is the phase change period.) (Setting N to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (2) is merely an example and is not the only option. Therefore, the phase change value y(i) = e j×δ(i) It shall be represented as follows.

[0300] In this case, z1(i) and z2(i) can be expressed by equation (3), where δ(i) is a real number. Furthermore, z1(i) and z2(i) are transmitted from the transmitting device at the same time and frequency (same frequency band). In equation (3), the phase change value is not limited to that given in equation (2); for example, a method of periodically and regularly changing the phase can be considered.

[0301] As explained in Embodiment 1, the (precoding) matrices in equations (1) and (3) can be those from equations (5) to (36), etc. (However, the precoding matrices are not limited to these. (The same applies to Embodiment 1.))

[0302] The insertion unit 207A receives the weighted combined signal 204A, the pilot symbol signal (pa(t)) (t: time) (251A), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208A based on the frame configuration information contained in the control signal 200.

[0303] Similarly, the insertion unit 207B receives the phase-shifted signal 206B, the pilot symbol signal (pb(t))(251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208B based on the frame configuration information contained in the control signal 200.

[0304] The phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. Let the baseband signal 208A be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i), where j is the imaginary unit.

[0305] As described in Embodiment 1 and other documents, the operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209A is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0306] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as y'(i). Then the phase-shifted signal 210B(y(i)) is given by y(i) = e j×τ(i) It can be expressed as ×y'(i), where j is the imaginary unit.

[0307] As described in Embodiment 1, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0308] A distinctive feature here is that the phase shifting method using ε(i) and the phase shifting method using τ(i) are different. Alternatively, the value of the cyclic delay amount of CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) set in the phase shifting unit 209A is different from the value of the cyclic delay amount of CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) set in the phase shifting unit 209B.

[0309] Figure 3 shows an example of the configuration of the wireless units 107_A and 107_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0310] Figure 4 shows the frame configuration of the transmission signal 108_A in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0311] Figure 5 shows the frame configuration of the transmitted signal 108_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0312] When a symbol exists on carrier A at time $B in Figure 4, and a symbol exists on carrier A at time $B in Figure 5, the symbols on carrier A at time $B in Figure 4 and the symbols on carrier A at time $B in Figure 5 will be transmitted at the same time and on the same frequency. Note that the frame configuration is not limited to Figures 4 and 5; Figures 4 and 5 are merely examples of frame configurations.

[0313] Furthermore, the other symbols in Figures 4 and 5 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 5 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 4, then it will be transmitting the same data (same control information).

[0314] It is assumed that the receiving device will receive the frames in Figure 4 and Figure 5 simultaneously, but the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 4 or only the frames in Figure 5.

[0315] Figure 6 shows an example of the configuration of the control information generation part for generating the control information signal 253 in Figure 2. Since a detailed explanation was given in Embodiment 1, the explanation will be omitted here.

[0316] Figure 7 shows an example of the configuration of antenna section #A (109_A) and antenna section #B (109_B) in Figure 1 (an example in which antenna section #A (109_A) and antenna section #B (109_B) are composed of multiple antennas). A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0317] Figure 8 shows an example of the configuration of a receiving device that receives a modulated signal when the transmitting device in Figure 1 transmits a transmission signal with the frame configuration shown in Figures 4 and 5, for example. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0318] Figure 10 shows an example of the configuration of antenna section #X (801X) and antenna section #Y (801Y) in Figure 8. (This is an example where antenna section #X (801X) and antenna section #Y (801Y) are composed of multiple antennas.) As Figure 10 was explained in detail in Embodiment 1, its explanation will be omitted here.

[0319] Next, as shown in Figure 1, the signal processing unit 106 of the transmitting device has phase shifting units 205B and 209A and 209B inserted, as shown in Figure 19. Its features and effects will be explained below.

[0320] As explained using Figures 4 and 5, the phase shifting unit 205B performs precoding (weighted synthesis) on the mapped signal s1(i)(201A) (where i is the symbol number and i is a non-negative integer) obtained by mapping using the first sequence and the mapped signal s2(i)(201B) obtained by mapping using the second sequence, and then performs a phase shift on one of the resulting weighted synthesized signals 204A and 204B. The weighted synthesized signal 204A and the phase-shifted signal 206B are then transmitted at the same frequency and at the same time. Therefore, in Figures 4 and 5, the phase shift is applied to the data symbol 502 in Figure 5. (In the case of Figure 19, the phase shifting unit 205 is applied to the weighted combined signal 204B, so the phase shift is applied to the data symbol 502 in Figure 5. If the phase shift is applied to the weighted combined signal 204A, the phase shift will be applied to the data symbol 402 in Figure 4. This point will be explained later.)

[0321] For example, Figure 11 shows the frame from Figure 5 with carriers 1 through 5 and time points $4 through $6 extracted. As with Figure 5, 501 is the pilot symbol, 502 is the data symbol, and 503 is the other symbol.

[0322] As described above, in the symbols shown in Figure 11, the phase change unit 205B will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0323] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×δ15(i)" and the phase change value of the data symbol (carrier 2, time $5) is "e j×δ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×δ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×δ45(i) " and the phase change value of the data symbol (carrier 5, time $5) is "e j×δ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×δ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×δ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×δ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×δ56(i) "

[0324] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205B.

[0325] This is a distinctive feature of the phase shifting unit 205B. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205B.)

[0326] As an example of the phase shifting applied to data symbols by the phase shifting unit 205B, one method is to apply a regular phase shift (with a phase shift period N) to the data symbols, as shown in equation (2). (However, this is not the only method of phase shifting applied to data symbols.)

[0327] This approach improves the data reception quality in receiving devices for MIMO-transmitted data symbols (transmitting multiple streams) in environments where direct waves are dominant, particularly in LOS (Line of Sight) environments. This effect will be explained below.

[0328] For example, let's assume that the modulation scheme used in the mapping unit 104 in Figure 1 is QPSK (Quadrature Phase Shift Keying). (The mapped signal 201A in Figure 19 is a QPSK signal, and the mapped signal 201B is also a QPSK signal. In other words, two QPSK streams will be transmitted.) Then, in the signal processing unit 811 in Figure 8, for example, channel estimation signals 806_1 and 806_2 will be used to obtain 16 candidate signal points. (QPSK can transmit 2 bits, and with 2 streams, a total of 4 bits will be transmitted. Therefore, 2 4 (There are 16 candidate signal points.) (Note that another 16 candidate signal points can be obtained using channel estimation signals 808_1 and 808_2, but the explanation will be the same. Therefore, we will focus on and explain the 16 candidate signal points obtained using channel estimation signals 806_1 and 806_2.)

[0329] An example of this state is shown in Figure 12. In both Figure 12(A) and Figure 12(B), the horizontal axis represents the in-phase I and the vertical axis represents the orthogonal Q. In the in-phase I-orthogonal Q plane, there are 16 candidate signal points. (Of these 16 candidate signal points, one is the signal point transmitted by the transmitting device. This is why they are called "16 candidate signal points.")

[0330] In environments where direct waves are dominant, especially in LOS environments, Case 1: If the phase shifting unit 205B in Figure 19 does not exist (i.e., if the phase shifting unit 205B in Figure 19 is not performed) Let's consider this.

[0331] In the "first case," since no phase change is performed, it is possible to fall into a state like that shown in Figure 12(A). If the state shown in Figure 12(A) occurs, there are areas where the signal points are densely packed (closely separated), such as "signal points 1201 and 1202," "signal points 1203, 1204, 1205, and 1206," and "signal points 1207 and 1208," which may cause a decrease in the data reception quality in the receiving device shown in Figure 8.

[0332] To overcome this challenge, a phase shifting unit 205B is inserted in Figure 19. When the phase shifting unit 205B is inserted, symbol numbers i will have a mix of symbol numbers where the signal points are dense (close distance between signal points), as shown in Figure 12(A), and symbol numbers where the signal points are far apart, as shown in Figure 12(B). By introducing an error correction code to address this situation, a high error correction capability can be obtained, resulting in high data reception quality in the receiving device shown in Figure 8.

[0333] Furthermore, in Figure 19, the phase shifting unit 205B in Figure 19 does not perform phase shifting on the "pilot symbol and preamble," which are used for channel estimation to demodulate (detect) the data symbols. This makes it possible to achieve a situation in the data symbols where "symbol number i has a mix of symbol numbers where the signal points are dense (close distance between signal points) as in Figure 12(A) and symbol numbers where the signal points are far apart as in Figure 12(B)."

[0334] However, even if the phase shift is applied in the phase shifting unit 205B in Figure 19 to the "pilot symbol and preamble," which are used for channel estimation to demodulate (detect) data symbols, it may still be possible to achieve a situation where, in the data symbols, "symbol number i contains both symbol numbers where signal points are densely packed (close distance between signal points) as shown in Figure 12(A) and symbol numbers where signal points are far apart as shown in Figure 12(B)." In this case, some condition must be added to the pilot symbol and preamble when performing the phase shift. For example, one could establish a separate rule from the phase shifting rule for data symbols and "apply phase shifting to the pilot symbol and / or preamble." As an example, one could apply a phase shift with period N to the data symbols regularly and a phase shift with period M to the pilot symbol and / or preamble regularly. (N and M are integers greater than or equal to 2.)

[0335] As previously mentioned, the phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. Let the baseband signal 208A be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. The operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A characteristic of the phase shifting unit 209A is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), etc.). (In the case of Figure 19, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 4.)

[0336] Therefore, in the frame of Figure 4, the phase shifting unit 209A in Figure 19 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403).

[0337] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift." ...

[0338] As previously mentioned, the phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, performs a phase shift on the baseband signal 208B based on the control signal 200, and outputs the phase-shifted signal 210B. Let the baseband signal 208B be a function of symbol number i (where i is a non-negative integer), and be represented as y'(i). Then the phase-shifted signal 210B(y(i)) is given by y(i) = e j×τ(i)It can be expressed as ×y'(i), where j is the imaginary unit. The operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A characteristic of the phase shifting unit 209B is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), etc.). (In the case of Figure 19, since the phase shifting unit 209B performs phase shifting on the baseband signal 208B, it will perform phase shifting on each symbol shown in Figure 5.)

[0339] Therefore, in the frame of Figure 5, the phase shifting unit 209B in Figure 19 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503).

[0340] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift."

[0341] Figure 13 shows a different frame configuration for the transmitted signal 108_A in Figure 1 compared to Figure 4. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0342] Figure 14 shows a different frame configuration for the transmitted signal 108_B in Figure 1 compared to Figure 5. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0343] When a symbol exists on carrier A at time $B in Figure 13, and a symbol exists on carrier A at time $B in Figure 14, the symbols on carrier A at time $B in Figure 13 and the symbols on carrier A at time $B in Figure 14 will be transmitted at the same time and on the same frequency. Note that the frame configurations in Figures 13 and 14 are merely examples.

[0344] Furthermore, the other symbols in Figures 13 and 14 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 19. Therefore, if the other symbol 503 in Figure 14 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 13, then it will be transmitting the same data (same control information).

[0345] Although it is assumed that the receiving device will receive the frames in Figure 13 and Figure 14 simultaneously, the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 13 or only the frames in Figure 14.

[0346] The phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. The baseband signal 208A is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. Furthermore, the operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209A is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 19, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 13.)

[0347] Therefore, in the frame of Figure 13, the phase shifting unit 209A in Figure 19 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0348] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0349] Let Ω(i) represent the phase change value in the phase change section 209A. The baseband signal 208A is x'(i), and the signal 210A after phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds true.

[0350] For example, set the phase change value to equation (38). (Q is an integer greater than or equal to 2, and Q is the period of the phase change.) (j is the imaginary unit) However, equation (38) is merely an example and is not the only one.

[0351] For example, Ω(i) may be set to perform a phase change so that it has a period Q.

[0352] Alternatively, as shown in Figures 4 and 13, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. • For carrier 1 in Figures 4 and 13, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 4 and 13, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 4 and 13, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 4 and 13, the phase change value is given by equation (42), regardless of time. ...

[0353] The above is an example of the operation of the phase shifting unit 209A in Figure 19.

[0354] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as y'(i). Then the phase-shifted signal 210B(y(i)) is given by y(i) = e j×τ(i) It can be expressed as ×y'(i), where j is the imaginary unit. Furthermore, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 19, since the phase shifting unit 209B performs phase shifting on the baseband signal 208B, it will perform phase shifting on each symbol shown in Figure 14.)

[0355] Therefore, in the frame of Figure 14, the phase shifting unit 209B in Figure 19 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0356] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 19 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0357] Let Ω(i) represent the phase change value in the phase change section 209B. The baseband signal 208B is y'(i), and the signal 210B after phase change is y(i). Therefore, y(i) = Δ(i) × y'(i) holds true.

[0358] For example, set the phase change value as follows: (R is an integer greater than or equal to 2, and R is the period of the phase change. It is preferable that the values ​​of Q and R in equation (38) are different.)

[0359]

number

[0360] For example, Δ(i) may be set to perform a phase change so that it has a period R.

[0361] Note that the phase changing methods of phase changing unit 209A and phase changing unit 209B are different. For example, the periods may be the same or different.

[0362] Alternatively, for example, in Figures 5 and 14, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. For carrier 1 in Figures 5 and 14, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 5 and 14, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 5 and 14, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 5 and 14, the phase change value is given by equation (42), regardless of time. ...

[0363] (Although the phase change values ​​are described as equations (39), (40), (41), and (42), the phase change methods of phase change unit 209A and phase change unit 209B are assumed to be different.)

[0364] The above is an example of the operation of the phase shifting unit 209B shown in Figure 19.

[0365] The effects obtained by the phase shifting units 209A and 209B in Figure 19 will be explained.

[0366] The other symbols 403 and 503 in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, are assumed to contain control information symbols. As previously explained, the other symbols 503 in Figure 5, at the same time and on the same frequency (same carrier) as the other symbols 403, transmit the same data (same control information) when transmitting control information.

[0367] Now, consider the following case.

[0368] Case 2: The control information symbol is transmitted using either antenna unit #A (109_A) or antenna unit #B (109_B) shown in Figure 1.

[0369] In the case of transmission as in "Case 2," since only one antenna transmits the control information symbols, the spatial diversity gain is smaller compared to the case where "both antenna unit #A (109_A) and antenna unit #B (109_B) are used to transmit the control information symbols." Therefore, in "Case 2," the data reception quality will be reduced even when received by the receiver in Figure 8. Consequently, in terms of improving data reception quality, it is better to "transmit the control information symbols using both antenna unit #A (109_A) and antenna unit #B (109_B)."

[0370] Case 3: Control information symbols are transmitted using both antenna section #A (109_A) and antenna section #B (109_B) in Figure 1. However, no phase shifting is performed by the phase shifting sections 209A and 209B in Figure 19.

[0371] In the case of transmission as in "Case 3," the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are identical (or have a specific phase difference). Therefore, depending on the radio wave propagation environment, the receiver in Figure 8 may receive a very poor signal, and both modulated signals may be affected by the same multipath. As a result, the receiver in Figure 8 faces the problem of reduced data reception quality.

[0372] To mitigate this issue, phase shifting units 209A and 209B are provided in Figure 19. Because the phase is shifted in the time or frequency direction, the possibility of a poor received signal in the receiver shown in Figure 8 can be reduced. Furthermore, since there is a high probability of differences in the multipath effects on the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B, diversity gain is likely to be obtained, thereby improving the data reception quality in the receiver shown in Figure 8.

[0373] For the reasons stated above, phase shifting units 209A and 209B are provided in Figure 19 to perform phase shifting.

[0374] Other symbols 403 and 503 include, in addition to control information symbols, symbols for signal detection, symbols for frequency and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) for demodulating and decoding control information symbols. Furthermore, the frames in Figures 4 and 5, or Figures 13 and 14, include pilot symbols 401 and 501, which can be used to demodulate and decode control information symbols with higher accuracy.

[0375] Furthermore, in the frames of Figures 4 and 5, or Figures 13 and 14, multiple streams are transmitted using the same frequency (band) and time using data symbols 402 and 502 (MIMO transmission is performed). In order to demodulate these data symbols, other symbols 403 and other symbols 503, which are included in the other symbols, are used for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variations).

[0376] At this time, the "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) included in the other symbols 403 and other symbols 503" are phase-shifted by the phase shifting units 209A and 209B, as previously mentioned.

[0377] In such circumstances, if this processing is not applied to data symbols 402 and 502, the receiving device will need to perform demodulation and decoding that reflects the phase shifting process performed by phase shifting units 209A and 209B when demodulating and decoding data symbols 402 and 502, which is likely to make the process complex. (This is because the phase shifting of "other symbols 403 and other symbols 503, including symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations)" is performed by phase shifting units 209A and 209B.)

[0378] However, as shown in Figure 19, when the phase shifting units 209A and 209B apply phase shifting to data symbols 402 and 502, the receiving device has the advantage of being able to (easily) demodulate and decode data symbols 402 and 502 using the channel estimation signal (propagation path variation estimation signal) estimated using "other symbols 403 and other symbols 503, which are included in the other symbols 403, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variation)".

[0379] In addition, as shown in Figure 19, when phase shifting is applied to data symbols 402 and 502 in phase shifting units 209A and 209B, the effect of abrupt drops in electric field strength in the frequency axis during multipath transmission can be reduced, which may result in improved reception quality of data from data symbols 402 and 502.

[0380] Thus, a distinctive feature is that the "target symbols to which the phase change unit 205B applies phase change" and the "target symbols to which the phase change units 209A and 209B apply phase change" are different.

[0381] As described above, by performing phase changes using the phase change unit 205B in Figure 19, it is possible to improve the data reception quality of data symbols 402 and 502, especially in LOS environments, and by performing phase changes using the phase change units 209A and 209B in Figure 19, it is possible to improve the reception quality of control information symbols included in, for example, "frames in Figures 4 and 5" or "frames in Figures 13 and 14," and to simplify the demodulation and decoding operations of data symbols 402 and 502.

[0382] Furthermore, by performing a phase change using the phase change unit 205B in Figure 19, the reception quality of data symbols 402 and 502 in the receiving device is improved, especially in an LOS environment. Additionally, by performing a phase change on data symbols 402 and 502 using the phase change units 209A and 209B in Figure 19, the reception quality of data symbols 402 and 502 is further improved.

[0383] Note that Q in equation (38) may be an integer less than or equal to -2, in which case the period of phase change will be the absolute value of Q. This point can also be applied to Embodiment 1.

[0384] Furthermore, R in equation (49) may be an integer less than or equal to -2, in which case the period of phase change is the absolute value of R.

[0385] Furthermore, considering the content explained in Supplement 1, it is desirable to set different values ​​for the cyclic delay amount set in the phase shifting unit 209A and the cyclic delay amount set in the phase shifting unit 209B.

[0386] (Embodiment 4) In this embodiment, a method for implementing a configuration different from that shown in Figure 2 of Embodiment 1 will be described.

[0387] Figure 1 shows an example of the configuration of a transmitting device such as a base station, access point, or broadcasting station in this embodiment. Details have been explained in Embodiment 1, so a further explanation will be omitted here.

[0388] The signal processing unit 106 takes the mapped signals 105_1 and 105_2, the signal group 110, and the control signal 100 as inputs, performs signal processing based on the control signal 100, and outputs the processed signals 106_A and 106_B. In this case, the processed signal 106_A is represented as u1(i) and the processed signal 106_B is represented as u2(i) (where i is a symbol number, for example, i is a non-negative integer). Details of the signal processing will be explained using Figure 20.

[0389] Figure 20 shows an example of the configuration of the signal processing unit 106 in Figure 1. The weighted synthesis unit (precoding unit) 203 takes the mapped signal 201A (corresponding to the mapped signal 105_1 in Figure 1), the mapped signal 201B (corresponding to the mapped signal 105_2 in Figure 1), and the control signal 200 (corresponding to the control signal 100 in Figure 1) as inputs, performs manual weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, the mapped signal 201A is represented as s1(t), the mapped signal 201B as s2(t), the weighted signal 204A as z1'(t), and the weighted signal 204B as z2'(t). Hereinafter, t is taken as time. (Let s1(t), s2(t), z1'(t), and z2'(t) be defined as complex numbers. (Therefore, they may also be real numbers.))

[0390] Here, it is treated as a function of time, but it may also be treated as a function of "frequency (carrier number)" or as a function of "time·frequency". It may also be treated as a function of "symbol number". This point is the same in Embodiment 1.

[0391] The weighted composition unit (precoding unit) 203 will perform the following calculations.

[0392]

number

[0393] The phase shifting unit 205A receives the weighted combined signal 204A and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204A and outputs the phase-shifted signal 206A. The phase-shifted signal 206A is denoted by z1(t), where z1(t) is defined as a complex number (it may also be a real number).

[0394] The specific operation of the phase shifting unit 205A will now be explained. For example, the phase shifting unit 205A applies a phase shift of w(i) to z1'(i). Therefore, z1(i) can be expressed as z1(i) = w(i) × z1'(i). (i is the symbol number; i is a non-negative integer.)

[0395] For example, set the phase change value as follows:

[0396]

number

[0397] The phase shifting unit 205B receives the weighted combined signal 204B and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204B and outputs the phase-shifted signal 206B. The phase-shifted signal 206B is denoted as z2(t), and z2(t) is defined as a complex number. (It may also be a real number.)

[0398] The specific operation of the phase shifting unit 205B will now be explained. For example, the phase shifting unit 205B applies a phase shift of y(i) to z2'(i). Therefore, z2(i) can be expressed as z2(i) = y(i) × z2'(i). (i is the symbol number; i is a non-negative integer.)

[0399] For example, the phase change value can be set as shown in equation (2). (N is an integer greater than or equal to 2, and N is the period of the phase change. N ≠ M) (Setting N to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (2) is merely an example and is not limited to this. Therefore, the phase change value y(i) = e j×δ(i) It shall be represented as follows.

[0400] In this case, z1(i) and z2(i) can be expressed by the following equations.

[0401]

number

[0402] Note that δ(i) and λ(i) are real numbers. Furthermore, z1(i) and z2(i) will be transmitted from the transmitting device at the same time and at the same frequency (same frequency band). In equation (52), the phase change value is not limited to equations (2) and (52); for example, a method of periodically and regularly changing the phase can be considered.

[0403] As explained in Embodiment 1, the (precoding) matrices in equations (50) and (52) can be those from equations (5) to (36), etc. (However, the precoding matrices are not limited to these. (The same applies to Embodiment 1.))

[0404] The insertion unit 207A receives the weighted combined signal 204A, the pilot symbol signal (pa(t)) (t: time) (251A), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208A based on the frame configuration information contained in the control signal 200.

[0405] Similarly, the insertion unit 207B receives the phase-shifted signal 206B, the pilot symbol signal (pb(t))(251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208B based on the frame configuration information contained in the control signal 200.

[0406] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i), where j is the imaginary unit.

[0407] As described in Embodiment 1, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0408] Figure 3 shows an example of the configuration of the wireless units 107_A and 107_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0409] Figure 4 shows the frame configuration of the transmission signal 108_A in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0410] Figure 5 shows the frame configuration of the transmitted signal 108_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0411] When a symbol exists on carrier A at time $B in Figure 4, and a symbol exists on carrier A at time $B in Figure 5, the symbols on carrier A at time $B in Figure 4 and the symbols on carrier A at time $B in Figure 5 will be transmitted at the same time and on the same frequency. Note that the frame configuration is not limited to Figures 4 and 5; Figures 4 and 5 are merely examples of frame configurations.

[0412] Furthermore, the other symbols in Figures 4 and 5 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 5 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 4, then it will be transmitting the same data (same control information).

[0413] It is assumed that the receiving device will receive the frames in Figure 4 and Figure 5 simultaneously, but the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 4 or only the frames in Figure 5.

[0414] Figure 6 shows an example of the configuration of the control information generation part for generating the control information signal 253 in Figure 2. Since a detailed explanation was given in Embodiment 1, the explanation will be omitted here.

[0415] Figure 7 shows an example of the configuration of antenna section #A (109_A) and antenna section #B (109_B) in Figure 1 (an example in which antenna section #A (109_A) and antenna section #B (109_B) are composed of multiple antennas). A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0416] Figure 8 shows an example of the configuration of a receiving device that receives a modulated signal when the transmitting device in Figure 1 transmits a transmission signal with the frame configuration shown in Figures 4 and 5, for example. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0417] Figure 10 shows an example of the configuration of antenna section #X (801X) and antenna section #Y (801Y) in Figure 8. (This is an example where antenna section #X (801X) and antenna section #Y (801Y) are composed of multiple antennas.) As Figure 10 was explained in detail in Embodiment 1, its explanation will be omitted here.

[0418] Next, as shown in Figure 1, the signal processing unit 106 of the transmitting device has phase shifting units 205A, 205B and phase shifting unit 209A inserted, as shown in Figure 20. Its features and effects will be explained below.

[0419] As explained using Figures 4 and 5, the phase shifting units 205A and 205B perform precoding (weighted synthesis) on the mapped signal s1(i)(201A) obtained by mapping using the first sequence (where i is the symbol number and i is a non-negative integer) and the mapped signal s2(i)(201B) obtained by mapping using the second sequence, and then perform phase shifting on the resulting weighted synthesized signals 204A and 204B. The phase-shifted signals 206A and 206B are then transmitted at the same frequency and time. Therefore, in Figures 4 and 5, the phase shifting is applied to data symbol 402 in Figure 4 and data symbol 502 in Figure 5.

[0420] For example, Figure 11 shows the frame from Figure 4 with carriers 1 through 5 and time points $4 through $6 extracted. As in Figure 4, 401 is the pilot symbol, 402 is the data symbol, and 403 is the other symbol.

[0421] As described above, in the symbols shown in Figure 11, the phase change unit 205A will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0422] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×λ15(i) " and the phase change value of the data symbol (carrier 2, time $5) is "e j×λ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×λ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×λ45(i) " and the phase change value of the data symbol (carrier 5, time $5) is "e j×λ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×λ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×λ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×λ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×λ56(i) "

[0423] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205A.

[0424] This is a distinctive feature of the phase shifting unit 205A. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205A.)

[0425] As an example of the phase change applied to the data symbol by the phase change unit 205A, one method is to apply a regular phase change (with a phase change period N) to the data symbol, as shown in equation (50). (However, this is not the only method of phase change applied to the data symbol.)

[0426] For example, Figure 11 shows the frame from Figure 5 with carriers 1 through 5 and time points $4 through $6 extracted. As with Figure 5, 501 is the pilot symbol, 502 is the data symbol, and 503 is the other symbol.

[0427] As described above, in the symbols shown in Figure 11, the phase change unit 205B will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0428] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×δ15(i) " and the phase change value of the data symbol (carrier 2, time $5) is "e j×δ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×δ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×δ45(i) " and the phase change value of the data symbol (carrier 5, time $5) is "e j×δ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×δ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×δ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×δ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×δ56(i) "

[0429] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205B.

[0430] This is a distinctive feature of the phase shifting unit 205B. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205B.)

[0431] As an example of the phase shifting applied to data symbols by the phase shifting unit 205B, one method is to apply a regular phase shift (with a phase shift period N) to the data symbols, as shown in equation (2). (However, this is not the only method of phase shifting applied to data symbols.)

[0432] This approach improves the data reception quality in receiving devices for MIMO-transmitted data symbols (transmitting multiple streams) in environments where direct waves are dominant, particularly in LOS (Line of Sight) environments. This effect will be explained below.

[0433] For example, let's assume that the modulation scheme used in the mapping unit 104 in Figure 1 is QPSK (Quadrature Phase Shift Keying). (The mapped signal 201A in Figure 18 is a QPSK signal, and the mapped signal 201B is also a QPSK signal. In other words, two QPSK streams will be transmitted.) Then, in the signal processing unit 811 in Figure 8, for example, channel estimation signals 806_1 and 806_2 will be used to obtain 16 candidate signal points. (QPSK can transmit 2 bits, and with 2 streams, a total of 4 bits will be transmitted. Therefore, 2 4 (There are 16 candidate signal points.) (Note that another 16 candidate signal points can be obtained using channel estimation signals 808_1 and 808_2, but the explanation will be the same. Therefore, we will focus on and explain the 16 candidate signal points obtained using channel estimation signals 806_1 and 806_2.)

[0434] An example of this state is shown in Figure 12. In both Figure 12(A) and Figure 12(B), the horizontal axis represents the in-phase I and the vertical axis represents the orthogonal Q. In the in-phase I-orthogonal Q plane, there are 16 candidate signal points. (Of these 16 candidate signal points, one is the signal point transmitted by the transmitting device. This is why they are called "16 candidate signal points.")

[0435] In environments where direct waves are dominant, especially in LOS environments, Case 1: If the phase shifting units 205A and 205B in Figure 20 do not exist (i.e., if the phase shifting is not performed by the phase shifting units 205A and 205B in Figure 20) Let's consider this.

[0436] In the "first case," since no phase change is performed, it is possible to fall into a state like that shown in Figure 12(A). If the state shown in Figure 12(A) occurs, there are areas where the signal points are densely packed (closely separated), such as "signal points 1201 and 1202," "signal points 1203, 1204, 1205, and 1206," and "signal points 1207 and 1208," which may cause a decrease in the data reception quality in the receiving device shown in Figure 8.

[0437] To overcome this challenge, phase shifting units 205A and 205B are inserted in Figure 20. When phase shifting units 205A and 205B are inserted, symbol numbers i will have a mix of symbol numbers where the signal points are dense (close distance between signal points), as shown in Figure 12(A), and symbol numbers where the signal points are far apart, as shown in Figure 12(B). By introducing error correction codes to address this situation, high error correction capability can be achieved, resulting in high data reception quality in the receiving device shown in Figure 8.

[0438] In Figure 20, the pilot symbol and preamble, which are used for demodulating (detecting) data symbols and for channel estimation, are not phase-shifted in the phase shifting sections 205A and 205B of Figure 20. This makes it possible to achieve a situation in the data symbols where, for each symbol number i, there is a mixture of symbol numbers where the signal points are densely packed (close distance between signal points) as shown in Figure 12(A), and symbol numbers where the signal points are far apart as shown in Figure 12(B).

[0439] However, even if phase shifting is performed on the pilot symbol and preamble, which are used for channel estimation to demodulate (detect) data symbols, in the phase shifting units 205A and 205B of Figure 20, it may still be possible to achieve a situation where, for each symbol number i, there is a mixture of symbol numbers where the signal points are densely packed (close distance between signal points) as shown in Figure 12(A) and symbol numbers where the signal points are far apart as shown in Figure 12(B). In this case, some condition must be added to the pilot symbol and preamble when performing phase shifting. For example, one could establish a separate rule from the phase shifting rule for data symbols and apply phase shifting to the pilot symbol and / or preamble. As an example, one could apply phase shifting with a period N to the data symbols regularly and phase shifting with a period M to the pilot symbol and / or preamble regularly. (N and M are integers greater than or equal to 2.)

[0440] As previously mentioned, the phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, performs a phase shift on the baseband signal 208B based on the control signal 200, and outputs the phase-shifted signal 210B. Let the baseband signal 208B be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. The operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Literature 2 and Non-Patent Literature 3. A characteristic of the phase shifting unit 209B is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), etc.). (In the case of Figure 20, since the phase shifting unit 209B performs phase shifting on the baseband signal 208B, it will perform phase shifting on each symbol shown in Figure 5.)

[0441] Therefore, in the frame of Figure 5, the phase shifting unit 209B in Figure 20 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503).

[0442] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift." ...

[0443] Figure 13 shows a different frame configuration for the transmitted signal 108_A in Figure 1 compared to Figure 4. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0444] Figure 14 shows a different frame configuration for the transmitted signal 108_B in Figure 1 compared to Figure 5. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0445] When a symbol exists on carrier A at time $B in Figure 13, and a symbol exists on carrier A at time $B in Figure 14, the symbols on carrier A at time $B in Figure 13 and the symbols on carrier A at time $B in Figure 14 will be transmitted at the same time and on the same frequency. Note that the frame configurations in Figures 13 and 14 are merely examples.

[0446] Furthermore, the other symbols in Figures 13 and 14 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 20. Therefore, if the other symbol 503 in Figure 14 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 13, then it will be transmitting the same data (same control information).

[0447] Although it is assumed that the receiving device will receive the frames in Figure 13 and Figure 14 simultaneously, the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 13 or only the frames in Figure 14.

[0448] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i) (where j is the imaginary unit). Furthermore, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 20, since the phase shifting unit 209B performs phase shifting on the baseband signal 208B, it will perform phase shifting on each symbol shown in Figure 14.)

[0449] Therefore, in the frame of Figure 14, the phase shifting unit 209B in Figure 20 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0450] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 20 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0451] Let Ω(i) represent the phase change value in the phase change section 209B. The baseband signal 208B is x'(i), and the signal 210B after phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds true.

[0452] For example, set the phase change value to equation (38). (Q is an integer greater than or equal to 2, and Q is the period of the phase change.) (j is the imaginary unit) However, equation (38) is merely an example and is not the only one.

[0453] For example, Ω(i) may be set to perform a phase change so that it has a period Q.

[0454] Alternatively, for example, in Figures 5 and 14, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. For carrier 1 in Figures 5 and 14, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 5 and 14, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 5 and 14, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 5 and 14, the phase change value is given by equation (42), regardless of time. ...

[0455] The above is an example of the operation of the phase shifting unit 209B shown in Figure 20.

[0456] The effects obtained by the phase shifting unit 209B in Figure 20 will be explained.

[0457] The other symbols 403 and 503 in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, are assumed to contain control information symbols. As previously explained, the other symbols 503 in Figure 5, at the same time and on the same frequency (same carrier) as the other symbols 403, transmit the same data (same control information) when transmitting control information.

[0458] Now, consider the following case.

[0459] Case 2: The control information symbol is transmitted using either antenna unit #A (109_A) or antenna unit #B (109_B) shown in Figure 1.

[0460] In the case of transmission as in "Case 2," since only one antenna transmits the control information symbols, the spatial diversity gain is smaller compared to the case where "both antenna unit #A (109_A) and antenna unit #B (109_B) are used to transmit the control information symbols." Therefore, in "Case 2," the data reception quality will be reduced even when received by the receiver in Figure 8. Consequently, in terms of improving data reception quality, it is better to "transmit the control information symbols using both antenna unit #A (109_A) and antenna unit #B (109_B)."

[0461] Case 3: The control information symbol is transmitted using both antenna section #A (109_A) and antenna section #B (109_B) in Figure 1. However, no phase shift is performed in the phase shift section 209B in Figure 20.

[0462] In the case of transmission as in "Case 3," the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are identical (or have a specific phase difference). Therefore, depending on the radio wave propagation environment, the receiver in Figure 8 may receive a very poor signal, and both modulated signals may be affected by the same multipath. As a result, the receiver in Figure 8 faces the problem of reduced data reception quality.

[0463] To mitigate this issue, a phase shifting unit 209B is provided in Figure 20. This changes the phase in the time or frequency direction, thereby reducing the possibility of a poor received signal in the receiver shown in Figure 8. Furthermore, since there is a high probability that the multipath effects on the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are different, diversity gain is likely to be obtained, which improves the data reception quality in the receiver shown in Figure 8.

[0464] For the reasons stated above, a phase shifting unit 209B is provided in Figure 20 to perform phase shifting.

[0465] Other symbols 403 and 503 include, in addition to control information symbols, symbols for signal detection, symbols for frequency and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) for demodulating and decoding control information symbols. Furthermore, the frames in Figures 4 and 5, or Figures 13 and 14, include pilot symbols 401 and 501, which can be used to demodulate and decode control information symbols with higher accuracy.

[0466] Furthermore, in the frames of Figures 4 and 5, or Figures 13 and 14, multiple streams are transmitted using the same frequency (band) and time using data symbols 402 and 502 (MIMO transmission is performed). In order to demodulate these data symbols, other symbols 403 and other symbols 503, which are included in the other symbols, are used for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variations).

[0467] At this time, the "other symbols 403 and other symbols 503, which include symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations)," undergo phase shifting by the phase shifting unit 209B, as previously mentioned.

[0468] In such circumstances, if this process is not applied to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 502), the receiving device will need to perform demodulation and decoding that reflects the phase change processing performed by the phase change unit 209B when demodulating and decoding data symbol 402 and data symbol 502, and this process is likely to become complex. (This is because the phase change is performed by the phase change unit 209B on "other symbols 403 and other symbols 503, including symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations).")

[0469] However, as shown in Figure 20, when the phase shifting unit 209B applies a phase shift to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 502), the receiving device has the advantage of being able to (easily) demodulate and decode data symbol 402 and data symbol 502 using the channel estimation signal (propagation path variation estimation signal) estimated using "other symbols 403 and other symbols 503, which are included in the other symbols for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variation)".

[0470] In addition, as shown in Figure 20, when the phase shifting unit 209B applies phase shifting to data symbol 402 and data symbol 502 (in the above description, to data symbol 502), the effect of abrupt drops in electric field strength on the frequency axis in multipath can be reduced, which may result in an improvement in the reception quality of data for data symbol 402 and data symbol 502.

[0471] Thus, a distinctive feature is that the "target symbols to which phase changes are applied by phase changing units 205A and 205B" and the "target symbols to which phase changes are applied by phase changing unit 209B" are different.

[0472] As described above, by performing phase changes using the phase change units 205A and 205B in Figure 20, it is possible to improve the data reception quality of data symbols 402 and 502 in the receiving device, especially in an LOS environment. Furthermore, by performing phase changes using the phase change unit 209B in Figure 20, it is possible to improve the reception quality of control information symbols included in, for example, "frames in Figures 4 and 5" or "frames in Figures 13 and 14" in the receiving device, and to simplify the demodulation and decoding operations of data symbols 402 and 502.

[0473] Furthermore, by performing phase changes using the phase change units 205A and 205B in Figure 20, the reception quality of data symbols 402 and 502 in the receiving device is improved, especially in LOS environments. Additionally, by performing phase changes on data symbols 402 and 502 using the phase change unit 209B in Figure 20, the reception quality of data symbols 402 and 502 is further improved.

[0474] Note that Q in equation (38) may be an integer less than or equal to -2, in which case the period of phase change will be the absolute value of Q. This point can also be applied to Embodiment 1.

[0475] (Embodiment 5) In this embodiment, a method for implementing a configuration different from that shown in Figure 2 of Embodiment 1 will be described.

[0476] Figure 1 shows an example of the configuration of a transmitting device such as a base station, access point, or broadcasting station in this embodiment. Details have been explained in Embodiment 1, so a further explanation will be omitted here.

[0477] The signal processing unit 106 takes the mapped signals 105_1 and 105_2, the signal group 110, and the control signal 100 as inputs, performs signal processing based on the control signal 100, and outputs the processed signals 106_A and 106_B. In this case, the processed signal 106_A is represented as u1(i) and the processed signal 106_B is represented as u2(i) (where i is a symbol number, for example, i is a non-negative integer). Details of the signal processing will be explained using Figure 21.

[0478] Figure 21 shows an example of the configuration of the signal processing unit 106 in Figure 1. The weighted synthesis unit (precoding unit) 203 takes the mapped signal 201A (corresponding to the mapped signal 105_1 in Figure 1), the mapped signal 201B (corresponding to the mapped signal 105_2 in Figure 1), and the control signal 200 (corresponding to the control signal 100 in Figure 1) as inputs, performs manual weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, the mapped signal 201A is represented as s1(t), the mapped signal 201B as s2(t), the weighted signal 204A as z1'(t), and the weighted signal 204B as z2'(t). Hereinafter, t is taken as time. (Let s1(t), s2(t), z1'(t), and z2'(t) be defined as complex numbers. (Therefore, they may also be real numbers.))

[0479] Here, it is treated as a function of time, but it may also be treated as a function of "frequency (carrier number)" or as a function of "time·frequency". It may also be treated as a function of "symbol number". This point is the same in Embodiment 1.

[0480] The weighted composition unit (precoding unit) 203 will perform the calculation in equation (49).

[0481] The phase shifting unit 205A receives the weighted combined signal 204A and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204A and outputs the phase-shifted signal 206A. The phase-shifted signal 206A is denoted by z1(t), where z1(t) is defined as a complex number (it may also be a real number).

[0482] The specific operation of the phase shifting unit 205A will now be explained. For example, the phase shifting unit 205A applies a phase shift of w(i) to z1'(i). Therefore, z1(i) can be expressed as z1(i) = w(i) × z1'(i). (i is the symbol number; i is a non-negative integer.)

[0483] For example, set the phase change value as shown in equation (50).

[0484] (M is an integer greater than or equal to 2, and M is the phase change period.) (Setting M to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (50) is merely an example and is not limited to this. Therefore, the phase change value w(i) = e j×λ(i) It shall be represented as follows.

[0485] The phase shifting unit 205B receives the weighted combined signal 204B and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204B and outputs the phase-shifted signal 206B. The phase-shifted signal 206B is denoted as z2(t), and z2(t) is defined as a complex number. (It may also be a real number.)

[0486] The specific operation of the phase shifting unit 205B will now be explained. For example, the phase shifting unit 205B applies a phase shift of y(i) to z2'(i). Therefore, z2(i) can be expressed as z2(i) = y(i) × z2'(i). (i is the symbol number; i is a non-negative integer.)

[0487] For example, the phase change value can be set as shown in equation (2). (N is an integer greater than or equal to 2, and N is the period of the phase change. N ≠ M) (Setting N to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (2) is merely an example and is not limited to this. Therefore, the phase change value y(i) = e j×δ(i) It shall be represented as follows.

[0488] In this case, z1(i) and z2(i) can be expressed by equation (51).

[0489] Note that δ(i) and λ(i) are real numbers. Furthermore, z1(i) and z2(i) are transmitted from the transmitting device at the same time and at the same frequency (same frequency band). In equation (51), the phase change value is not limited to equations (2) and (51); for example, a method of periodically and regularly changing the phase can be considered.

[0490] As explained in Embodiment 1, the (precoding) matrices in equations (49) and (51) can be those from equations (5) to (36), etc. (However, the precoding matrices are not limited to these. (The same applies to Embodiment 1.))

[0491] The insertion unit 207A receives the weighted combined signal 204A, the pilot symbol signal (pa(t)) (t: time) (251A), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208A based on the frame configuration information contained in the control signal 200.

[0492] Similarly, the insertion unit 207B receives the phase-shifted signal 206B, the pilot symbol signal (pb(t))(251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208B based on the frame configuration information contained in the control signal 200.

[0493] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i), where j is the imaginary unit.

[0494] As described in Embodiment 1, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0495] Figure 3 shows an example of the configuration of the wireless units 107_A and 107_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0496] Figure 4 shows the frame configuration of the transmission signal 108_A in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0497] Figure 5 shows the frame configuration of the transmitted signal 108_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0498] When a symbol exists on carrier A at time $B in Figure 4, and a symbol exists on carrier A at time $B in Figure 5, the symbols on carrier A at time $B in Figure 4 and the symbols on carrier A at time $B in Figure 5 will be transmitted at the same time and on the same frequency. Note that the frame configuration is not limited to Figures 4 and 5; Figures 4 and 5 are merely examples of frame configurations.

[0499] Furthermore, the other symbols in Figures 4 and 5 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 5 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 4, then it will be transmitting the same data (same control information).

[0500] It is assumed that the receiving device will receive the frames in Figure 4 and Figure 5 simultaneously, but the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 4 or only the frames in Figure 5.

[0501] Figure 6 shows an example of the configuration of the control information generation part for generating the control information signal 253 in Figure 2. Since a detailed explanation was given in Embodiment 1, the explanation will be omitted here.

[0502] Figure 7 shows an example of the configuration of antenna section #A (109_A) and antenna section #B (109_B) in Figure 1 (an example in which antenna section #A (109_A) and antenna section #B (109_B) are composed of multiple antennas). A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0503] Figure 8 shows an example of the configuration of a receiving device that receives a modulated signal when the transmitting device in Figure 1 transmits a transmission signal with the frame configuration shown in Figures 4 and 5, for example. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0504] Figure 10 shows an example of the configuration of antenna section #X (801X) and antenna section #Y (801Y) in Figure 8. (This is an example where antenna section #X (801X) and antenna section #Y (801Y) are composed of multiple antennas.) As Figure 10 was explained in detail in Embodiment 1, its explanation will be omitted here.

[0505] Next, as shown in Figure 1, the signal processing unit 106 of the transmitting device has phase shifting units 205A, 205B and phase shifting unit 209B inserted. Its features and effects will be explained below.

[0506] As explained using Figures 4 and 5, the phase shifting units 205A and 205B perform precoding (weighted synthesis) on the mapped signal s1(i)(201A) obtained by mapping using the first sequence (where i is the symbol number and i is a non-negative integer) and the mapped signal s2(i)(201B) obtained by mapping using the second sequence, and then perform phase shifting on the resulting weighted synthesized signals 204A and 204B. The phase-shifted signals 206A and 206B are then transmitted at the same frequency and time. Therefore, in Figures 4 and 5, the phase shifting is applied to data symbol 402 in Figure 4 and data symbol 502 in Figure 5.

[0507] For example, Figure 11 shows the frame from Figure 4 with carriers 1 through 5 and time points $4 through $6 extracted. As in Figure 4, 401 is the pilot symbol, 402 is the data symbol, and 403 is the other symbol.

[0508] As described above, in the symbols shown in Figure 11, the phase change unit 205A will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0509] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×λ15(i) " and the phase change value of the data symbol (carrier 2, time $5) is "e j×λ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×λ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×λ45(i)" and the phase change value of the data symbol (carrier 5, time $5) is "e j×λ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×λ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×λ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×λ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×λ56(i) "

[0510] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205A.

[0511] This is a distinctive feature of the phase shifting unit 205A. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205A.)

[0512] As an example of the phase change applied to the data symbol by the phase change unit 205A, one method is to apply a regular phase change (with a phase change period N) to the data symbol, as shown in equation (50). (However, this is not the only method of phase change applied to the data symbol.)

[0513] For example, Figure 11 shows the frame from Figure 5 with carriers 1 through 5 and time points $4 through $6 extracted. As with Figure 5, 501 is the pilot symbol, 502 is the data symbol, and 503 is the other symbol.

[0514] As described above, in the symbols shown in FIG. 11, for the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), the phase change unit 205B will perform phase change.

[0515] Therefore, in the symbols shown in FIG. 11, let the phase change value of the data symbol of (carrier 1, time $5) be "e j×δ15(i) ", let the phase change value of the data symbol of (carrier 2, time $5) be "e j×δ25(i) ", let the phase change value of the data symbol of (carrier 3, time $5) be "e j×δ35(i) ", let the phase change value of the data symbol of (carrier 4, time $5) be "e j×δ45(i) ", let the phase change value of the data symbol of (carrier 5, time $5) be "e j×δ55(i) ", let the phase change value of the data symbol of (carrier 1, time $6) be "e j×δ16(i) ", let the phase change value of the data symbol of (carrier 2, time $6) be "e j×δ26(i) ", let the phase change value of the data symbol of (carrier 4, time $6) be "e j×δ46(i) ", and let the phase change value of the data symbol of (carrier 5, time $6) be "e j×δ56(i) ".

[0516] On the other hand, in the symbols shown in FIG. 11, the other symbols of (carrier 1, time $4), (carrier 2, time $4), (carrier 3, time $4), (carrier 4, time $4), (carrier 5, time $4), and the pilot symbol of (carrier 3, time $6) are not the targets of the phase change by the phase change unit 205B.

[0517] This is a distinctive feature of the phase shifting unit 205B. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205B.)

[0518] As an example of the phase shifting applied to data symbols by the phase shifting unit 205B, one method is to apply a regular phase shift (with a phase shift period N) to the data symbols, as shown in equation (2). (However, this is not the only method of phase shifting applied to data symbols.)

[0519] This approach improves the data reception quality in receiving devices for MIMO-transmitted data symbols (transmitting multiple streams) in environments where direct waves are dominant, particularly in LOS (Line of Sight) environments. This effect will be explained below.

[0520] For example, let's assume that the modulation scheme used in the mapping unit 104 in Figure 1 is QPSK (Quadrature Phase Shift Keying). (The mapped signal 201A in Figure 18 is a QPSK signal, and the mapped signal 201B is also a QPSK signal. In other words, two QPSK streams will be transmitted.) Then, in the signal processing unit 811 in Figure 8, for example, channel estimation signals 806_1 and 806_2 will be used to obtain 16 candidate signal points. (QPSK can transmit 2 bits, and with 2 streams, a total of 4 bits will be transmitted. Therefore, 2 4 (There are 16 candidate signal points.) (Note that another 16 candidate signal points can be obtained using channel estimation signals 808_1 and 808_2, but the explanation will be the same. Therefore, we will focus on and explain the 16 candidate signal points obtained using channel estimation signals 806_1 and 806_2.)

[0521] An example of this state is shown in Figure 12. In both Figure 12(A) and Figure 12(B), the horizontal axis represents the in-phase I and the vertical axis represents the orthogonal Q. In the in-phase I-orthogonal Q plane, there are 16 candidate signal points. (Of these 16 candidate signal points, one is the signal point transmitted by the transmitting device. This is why they are called "16 candidate signal points.")

[0522] In environments where direct waves are dominant, especially in LOS environments, Case 1: If the phase shifting units 205A and 205B in Figure 21 do not exist (i.e., if the phase shifting is not performed by the phase shifting units 205A and 205B in Figure 21) Let's consider this.

[0523] In the "first case," since no phase change is performed, it is possible to fall into a state like that shown in Figure 12(A). If the state shown in Figure 12(A) occurs, there are areas where the signal points are densely packed (closely separated), such as "signal points 1201 and 1202," "signal points 1203, 1204, 1205, and 1206," and "signal points 1207 and 1208," which may cause a decrease in the data reception quality in the receiving device shown in Figure 8.

[0524] To overcome this challenge, phase shifting units 205A and 205B are inserted in Figure 21. When phase shifting units 205A and 205B are inserted, symbol numbers i will have a mixture of symbol numbers where the signal points are dense (close distance between signal points), as in Figure 12(A), and symbol numbers where the signal points are far apart, as in Figure 12(B). By introducing error correction codes to address this situation, high error correction capability can be obtained, resulting in high data reception quality in the receiving device shown in Figure 8.

[0525] Furthermore, in Figure 21, the "pilot symbol and preamble," which are used for channel estimation to demodulate (detect) data symbols, are not phase-shifted in the phase shifting sections 205A and 205B of Figure 21. This makes it possible to achieve a situation in the data symbols where "symbol number i has a mix of symbol numbers where the signal points are dense (close distance between signal points) as in Figure 12(A) and symbol numbers where the signal points are far apart as in Figure 12(B)."

[0526] However, for "pilot symbols, preambles", etc. that are used for channel estimation to demodulate (detect) data symbols, even if phase changes are performed in the phase change units 205A and 205B of FIG. 21, there may be a case where "in data symbols, there are symbol numbers with signal points being dense (the distance between signal points is short) as shown in FIG. 12(A) and symbol numbers with 'long distances between signal points' as shown in FIG. 12(B) mixed together" can be realized. In this case, some conditions must be added to the pilot symbols and preambles, and phase changes must be performed. For example, a rule different from the rule for phase changes for data symbols can be set, and a method of "performing phase changes on pilot symbols and / or preambles" can be considered. As an example, there is a method of regularly performing phase changes with a period N on data symbols and regularly performing phase changes with a period M on pilot symbols and / or preambles. (N and M are integers greater than or equal to 2.)

[0527] As described above, the phase change unit 209A takes the baseband signal 208A and the control signal 200 as inputs, performs a phase change on the baseband signal 208A based on the control signal 200, and outputs the signal 210A after the phase change. Let the baseband signal 208A be a function of the symbol number i (where i is an integer greater than or equal to 0), denoted as x'(i). Then, the signal 210A(x(i)) after the phase change is x(i) = e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. The operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A characteristic of the phase shifting unit 209A is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), etc.). (In the case of Figure 21, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 4.)

[0528] Therefore, in the frame of Figure 4, the phase shifting unit 209A in Figure 21 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403).

[0529] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift." ...

[0530] Figure 13 shows a different frame configuration for the transmitted signal 108_A in Figure 1 compared to Figure 4. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0531] Figure 14 shows a different frame configuration for the transmitted signal 108_B in Figure 1 compared to Figure 5. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0532] When a symbol exists on carrier A at time $B in Figure 13, and a symbol exists on carrier A at time $B in Figure 14, the symbols on carrier A at time $B in Figure 13 and the symbols on carrier A at time $B in Figure 14 will be transmitted at the same time and on the same frequency. Note that the frame configurations in Figures 13 and 14 are merely examples.

[0533] Furthermore, the other symbols in Figures 13 and 14 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 21. Therefore, if the other symbol 503 in Figure 14 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 13, then it will be transmitting the same data (same control information).

[0534] Although it is assumed that the receiving device will receive the frames in Figure 13 and Figure 14 simultaneously, the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 13 or only the frames in Figure 14.

[0535] The phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. The baseband signal 208A is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. Furthermore, the operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209A is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 21, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 13.)

[0536] Therefore, in the frame of Figure 13, the phase shifting unit 209A in Figure 21 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0537] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 21 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0538] Let Ω(i) represent the phase change value in the phase change section 209A. The baseband signal 208A is x'(i), and the signal 210A after phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds true.

[0539] For example, set the phase change value to equation (38). (Q is an integer greater than or equal to 2, and Q is the period of the phase change.) (j is the imaginary unit) However, equation (38) is merely an example and is not the only one.

[0540] For example, Ω(i) may be set to perform a phase change so that it has a period Q.

[0541] Alternatively, as shown in Figures 4 and 13, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. • For carrier 1 in Figures 4 and 13, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 4 and 13, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 4 and 13, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 4 and 13, the phase change value is given by equation (42), regardless of time. ...

[0542] The above is an example of the operation of the phase shifting unit 209A shown in Figure 21.

[0543] The effects obtained by the phase shifting unit 209A in Figure 21 will be explained.

[0544] The other symbols 403 and 503 in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, are assumed to contain control information symbols. As previously explained, the other symbols 503 in Figure 5, at the same time and on the same frequency (same carrier) as the other symbols 403, transmit the same data (same control information) when transmitting control information.

[0545] Now, consider the following case.

[0546] Case 2: The control information symbol is transmitted using either antenna unit #A (109_A) or antenna unit #B (109_B) shown in Figure 1.

[0547] In the case of transmission as in "Case 2," since only one antenna transmits the control information symbols, the spatial diversity gain is smaller compared to the case where "both antenna unit #A (109_A) and antenna unit #B (109_B) are used to transmit the control information symbols." Therefore, in "Case 2," the data reception quality will be reduced even when received by the receiver in Figure 8. Consequently, in terms of improving data reception quality, it is better to "transmit the control information symbols using both antenna unit #A (109_A) and antenna unit #B (109_B)."

[0548] Case 3: The control information symbol is transmitted using both antenna section #A (109_A) and antenna section #B (109_B) in Figure 1. However, no phase shift is performed in the phase shift section 209A in Figure 21.

[0549] In the case of transmission as in "Case 3," the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are identical (or have a specific phase difference). Therefore, depending on the radio wave propagation environment, the receiver in Figure 8 may receive a very poor signal, and both modulated signals may be affected by the same multipath. As a result, the receiver in Figure 8 faces the problem of reduced data reception quality.

[0550] To mitigate this issue, a phase shifting unit 209A is provided in Figure 21. This changes the phase in the time or frequency direction, thereby reducing the possibility of a poor received signal in the receiver shown in Figure 8. Furthermore, since there is a high probability that the multipath effects on the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are different, diversity gain is likely to be obtained, which improves the data reception quality in the receiver shown in Figure 8.

[0551] For the reasons stated above, a phase shifting unit 209A is provided in Figure 21 to perform phase shifting.

[0552] Other symbols 403 and 503 include, in addition to control information symbols, symbols for signal detection, symbols for frequency and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) for demodulating and decoding control information symbols. Furthermore, the frames in Figures 4 and 5, or Figures 13 and 14, include pilot symbols 401 and 501, which can be used to demodulate and decode control information symbols with higher accuracy.

[0553] Furthermore, in the frames of Figures 4 and 5, or Figures 13 and 14, multiple streams are transmitted using the same frequency (band) and time using data symbols 402 and 502 (MIMO transmission is performed). In order to demodulate these data symbols, other symbols 403 and other symbols 503, which are included in the other symbols, are used for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variations).

[0554] At this time, the "other symbols 403 and other symbols 503, which include symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations)," undergo phase shifting by the phase shifting unit 209A, as previously mentioned.

[0555] In such circumstances, if this process is not applied to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 402), the receiving device will need to perform demodulation and decoding that reflects the phase change processing performed by the phase change unit 209A when demodulating and decoding data symbol 402 and data symbol 502, and this process is likely to become complex. (This is because the phase change is performed by the phase change unit 209A on "other symbols 403 and other symbols 503, which include symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations).")

[0556] However, as shown in Figure 21, when the phase shifting unit 209A applies a phase shift to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 402), the receiving device has the advantage of being able to (easily) demodulate and decode data symbol 402 and data symbol 502 using the channel estimation signal (propagation path variation estimation signal) estimated using "other symbols 403 and other symbols 503, which are included in the other symbols for signal detection, frequency synchronization and time synchronization, and channel estimation (symbols for estimating propagation path variation)".

[0557] In addition, as shown in Figure 21, when the phase shifting unit 209A applies phase shifting to data symbol 402 and data symbol 502 (in the above explanation, to data symbol 402), the effect of abrupt drops in electric field strength on the frequency axis in multipath can be reduced, which may result in an improvement in the reception quality of data for data symbol 402 and data symbol 502.

[0558] Thus, a distinctive feature is that the "target symbols for which phase changes are applied by phase changing units 205A and 205B" and the "target symbols for which phase changes are applied by phase changing unit 209A" are different.

[0559] As described above, by performing phase changes using the phase change units 205A and 205B in Figure 21, it is possible to improve the data reception quality of data symbols 402 and 502, especially in an LOS environment, and by performing phase changes using the phase change unit 209A in Figure 21, it is possible to improve the reception quality of control information symbols included in, for example, "frames in Figures 4 and 5" or "frames in Figures 13 and 14," in the receiving device, and to simplify the demodulation and decoding operations of data symbols 402 and 502.

[0560] Furthermore, by performing phase changes using the phase change units 205A and 205B in Figure 21, the reception quality of data symbols 402 and 502 in the receiving device is improved, especially in LOS environments. Additionally, by performing phase changes on data symbols 402 and 502 using the phase change unit 209A in Figure 21, the reception quality of data symbols 402 and 502 is further improved.

[0561] Note that Q in equation (38) may be an integer less than or equal to -2, in which case the period of phase change will be the absolute value of Q. This point can also be applied to Embodiment 1.

[0562] (Embodiment 6) In this embodiment, a method for implementing a configuration different from that shown in Figure 2 of Embodiment 1 will be described.

[0563] Figure 1 shows an example of the configuration of a transmitting device such as a base station, access point, or broadcasting station in this embodiment. Details have been explained in Embodiment 1, so a further explanation will be omitted here.

[0564] The signal processing unit 106 receives the mapped signals 105_1 and 105_2, the signal group 110, and the control signal 100 as inputs, performs signal processing based on the control signal 100, and outputs the processed signals 106_A and 106_B. In this case, the processed signal 106_A is represented as u1(i) and the processed signal 106_B is represented as u2(i) (where i is a symbol number, for example, i is a non-negative integer). Details of the signal processing will be explained using Figure 22.

[0565] Figure 22 shows an example of the configuration of the signal processing unit 106 in Figure 1. The weighted synthesis unit (precoding unit) 203 takes the mapped signal 201A (corresponding to the mapped signal 105_1 in Figure 1), the mapped signal 201B (corresponding to the mapped signal 105_2 in Figure 1), and the control signal 200 (corresponding to the control signal 100 in Figure 1) as inputs, performs manual weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, the mapped signal 201A is represented as s1(t), the mapped signal 201B as s2(t), the weighted signal 204A as z1'(t), and the weighted signal 204B as z2'(t). Hereinafter, t is taken as time. (Let s1(t), s2(t), z1'(t), and z2'(t) be defined as complex numbers. (Therefore, they may also be real numbers.))

[0566] Here, it is treated as a function of time, but it may also be treated as a function of "frequency (carrier number)" or as a function of "time·frequency". It may also be treated as a function of "symbol number". This point is the same in Embodiment 1.

[0567] The weighted composition unit (precoding unit) 203 will perform the calculation in equation (49).

[0568] The phase shifting unit 205A receives the weighted combined signal 204A and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204A and outputs the phase-shifted signal 206A. The phase-shifted signal 206A is denoted by z1(t), where z1(t) is defined as a complex number (it may also be a real number).

[0569] The specific operation of the phase shifting unit 205A will now be explained. For example, the phase shifting unit 205A applies a phase shift of w(i) to z1'(i). Therefore, z1(i) can be expressed as z1(i) = w(i) × z1'(i). (i is the symbol number; i is a non-negative integer.)

[0570] For example, set the phase change value as shown in equation (50).

[0571] (M is an integer greater than or equal to 2, and M is the phase change period.) (Setting M to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (50) is merely an example and is not limited to this. Therefore, the phase change value w(i) = e j×λ(i) It shall be represented as follows.

[0572] The phase shifting unit 205B receives the weighted combined signal 204B and the control signal 200 as inputs. Based on the control signal 200, it performs a phase shift on the weighted combined signal 204B and outputs the phase-shifted signal 206B. The phase-shifted signal 206B is denoted as z2(t), and z2(t) is defined as a complex number. (It may also be a real number.)

[0573] The specific operation of the phase shifting unit 205B will now be explained. For example, the phase shifting unit 205B applies a phase shift of y(i) to z2'(i). Therefore, z2(i) can be expressed as z2(i) = y(i) × z2'(i). (i is the symbol number; i is a non-negative integer.)

[0574] For example, the phase change value can be set as shown in equation (2). (N is an integer greater than or equal to 2, and N is the period of the phase change. N ≠ M) (Setting N to an odd number greater than or equal to 3 may improve the data reception quality.) However, equation (2) is merely an example and is not limited to this. Therefore, the phase change value y(i) = e j×δ(i) It shall be represented as follows.

[0575] In this case, z1(i) and z2(i) can be expressed by equation (51).

[0576] Note that δ(i) and λ(i) are real numbers. Furthermore, z1(i) and z2(i) are transmitted from the transmitting device at the same time and at the same frequency (same frequency band). In equation (51), the phase change value is not limited to equations (2) and (51); for example, a method of periodically and regularly changing the phase can be considered.

[0577] As explained in Embodiment 1, the (precoding) matrices in equations (49) and (51) can be those from equations (5) to (36), etc. (However, the precoding matrices are not limited to these. (The same applies to Embodiment 1.))

[0578] The insertion unit 207A receives the weighted combined signal 204A, the pilot symbol signal (pa(t)) (t: time) (251A), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208A based on the frame configuration information contained in the control signal 200.

[0579] Similarly, the insertion unit 207B receives the phase-shifted signal 206B, the pilot symbol signal (pb(t))(251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200 as inputs, and outputs a baseband signal 208B based on the frame configuration information contained in the control signal 200.

[0580] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210B(x(i)) is given by x(i)=e j×ε(i) It can be expressed as ×x'(i), where j is the imaginary unit.

[0581] As described in Embodiment 1, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located in the frequency axis direction (applying phase shifting to data symbols, pilot symbols, control information symbols, etc.).

[0582] Figure 3 shows an example of the configuration of the wireless units 107_A and 107_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0583] Figure 4 shows the frame configuration of the transmission signal 108_A in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0584] Figure 5 shows the frame configuration of the transmitted signal 108_B in Figure 1. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0585] When a symbol exists on carrier A at time $B in Figure 4, and a symbol exists on carrier A at time $B in Figure 5, the symbols on carrier A at time $B in Figure 4 and the symbols on carrier A at time $B in Figure 5 will be transmitted at the same time and on the same frequency. Note that the frame configuration is not limited to Figures 4 and 5; Figures 4 and 5 are merely examples of frame configurations.

[0586] Furthermore, the other symbols in Figures 4 and 5 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 2. Therefore, if the other symbol 503 in Figure 5 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 4, then it will be transmitting the same data (same control information).

[0587] It is assumed that the receiving device will receive the frames in Figure 4 and Figure 5 simultaneously, but the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 4 or only the frames in Figure 5.

[0588] Figure 6 shows an example of the configuration of the control information generation part for generating the control information signal 253 in Figure 2. Since a detailed explanation was given in Embodiment 1, the explanation will be omitted here.

[0589] Figure 7 shows an example of the configuration of antenna section #A (109_A) and antenna section #B (109_B) in Figure 1 (an example in which antenna section #A (109_A) and antenna section #B (109_B) are composed of multiple antennas). A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0590] Figure 8 shows an example of the configuration of a receiving device that receives a modulated signal when the transmitting device in Figure 1 transmits a transmission signal with the frame configuration shown in Figures 4 and 5, for example. A detailed explanation was given in Embodiment 1, so the explanation will be omitted here.

[0591] Figure 10 shows an example of the configuration of antenna section #X (801X) and antenna section #Y (801Y) in Figure 8. (This is an example where antenna section #X (801X) and antenna section #Y (801Y) are composed of multiple antennas.) As Figure 10 was explained in detail in Embodiment 1, its explanation will be omitted here.

[0592] Next, as shown in Figure 1, the signal processing unit 106 of the transmitting device has phase shifting units 205A, 205B and 209B inserted, as shown in Figure 22. Its features and effects will be explained below.

[0593] As explained using Figures 4 and 5, the phase shifting units 205A and 205B perform precoding (weighted synthesis) on the mapped signal s1(i)(201A) obtained by mapping using the first sequence (where i is the symbol number and i is a non-negative integer) and the mapped signal s2(i)(201B) obtained by mapping using the second sequence, and then perform phase shifting on the resulting weighted synthesized signals 204A and 204B. The phase-shifted signals 206A and 206B are then transmitted at the same frequency and time. Therefore, in Figures 4 and 5, the phase shifting is applied to data symbol 402 in Figure 4 and data symbol 502 in Figure 5.

[0594] For example, Figure 11 shows the frame from Figure 4 with carriers 1 through 5 and time points $4 through $6 extracted. As in Figure 4, 401 is the pilot symbol, 402 is the data symbol, and 403 is the other symbol.

[0595] As described above, in the symbols shown in Figure 11, the phase change unit 205A will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0596] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×λ15(i) " and the phase change value of the data symbol (carrier 2, time $5) is "e j×λ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×λ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×λ45(i)" and the phase change value of the data symbol (carrier 5, time $5) is "e j×λ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×λ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×λ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×λ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×λ56(i) "

[0597] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205A.

[0598] This is a distinctive feature of the phase shifting unit 205A. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205A.)

[0599] As an example of the phase change applied to the data symbol by the phase change unit 205A, one method is to apply a regular phase change (with a phase change period N) to the data symbol, as shown in equation (50). (However, this is not the only method of phase change applied to the data symbol.)

[0600] For example, Figure 11 shows the frame from Figure 5 with carriers 1 through 5 and time points $4 through $6 extracted. As with Figure 5, 501 is the pilot symbol, 502 is the data symbol, and 503 is the other symbol.

[0601] As described above, in the symbols shown in Figure 11, the phase change unit 205B will perform a phase change on the data symbols of (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6).

[0602] Therefore, in the symbol shown in Figure 11, the phase change value of the data symbol (carrier 1, time $5) is "e j×δ15(i) " and the phase change value of the data symbol (carrier 2, time $5) is "e j×δ25(i) " and the phase change value of the data symbol for (carrier 3, time $5) is "e j×δ35(i) " and the phase change value of the data symbol (carrier 4, time $5) is "e j×δ45(i) " and the phase change value of the data symbol (carrier 5, time $5) is "e j×δ55(i) " and the phase change value of the data symbol (carrier 1, time $6) is "e j×δ16(i) " and the phase change value of the data symbol (carrier 2, time $6) is "e j×δ26(i) " and the phase change value of the data symbol for (carrier 4, time $6) is "e j×δ46(i) " and the phase change value of the data symbol (carrier 5, time $6) is "e j×δ56(i) "

[0603] On the other hand, in the symbols shown in Figure 11, the other symbols for (carrier 1, time $4), the other symbols for (carrier 2, time $4), the other symbols for (carrier 3, time $4), the other symbols for (carrier 4, time $4), the other symbols for (carrier 5, time $4), and the pilot symbol for (carrier 3, time $6) are not subject to phase change by the phase change unit 205B.

[0604] This is a distinctive feature of the phase shifting unit 205B. Note that, as shown in Figure 4, data carriers are arranged for the data symbols targeted for phase shifting in Figure 11: (carrier 1, time $5), (carrier 2, time $5), (carrier 3, time $5), (carrier 4, time $5), (carrier 5, time $5), (carrier 1, time $6), (carrier 2, time $6), (carrier 4, time $6), and (carrier 5, time $6), all of which are "same carrier, same time". In other words, in Figure 4, (carrier 1, time $5) is a data symbol, (carrier 2, time $5) is a data symbol, (carrier 3, time $5) is a data symbol, (carrier 4, time $5) is a data symbol, (carrier 5, time $5) is a data symbol, (carrier 1, time $6) is a data symbol, (carrier 2, time $6) is a data symbol, (carrier 4, time $6) is a data symbol, and (carrier 5, time $6) is a data symbol. (That is, data symbols performing MIMO transmission (transmitting multiple streams) are the target of phase shifting by the phase shifting unit 205B.)

[0605] As an example of the phase shifting applied to data symbols by the phase shifting unit 205B, one method is to apply a regular phase shift (with a phase shift period N) to the data symbols, as shown in equation (2). (However, this is not the only method of phase shifting applied to data symbols.)

[0606] This approach improves the data reception quality in receiving devices for MIMO-transmitted data symbols (transmitting multiple streams) in environments where direct waves are dominant, particularly in LOS (Line of Sight) environments. This effect will be explained below.

[0607] For example, let's assume that the modulation scheme used in the mapping unit 104 in Figure 1 is QPSK (Quadrature Phase Shift Keying). (The mapped signal 201A in Figure 18 is a QPSK signal, and the mapped signal 201B is also a QPSK signal. In other words, two QPSK streams will be transmitted.) Then, in the signal processing unit 811 in Figure 8, for example, channel estimation signals 806_1 and 806_2 will be used to obtain 16 candidate signal points. (QPSK can transmit 2 bits, and with 2 streams, a total of 4 bits will be transmitted. Therefore, 2 4 (There are 16 candidate signal points.) (Note that another 16 candidate signal points can be obtained using channel estimation signals 808_1 and 808_2, but the explanation will be the same. Therefore, we will focus on and explain the 16 candidate signal points obtained using channel estimation signals 806_1 and 806_2.)

[0608] An example of this state is shown in Figure 12. In both Figure 12(A) and Figure 12(B), the horizontal axis represents the in-phase I and the vertical axis represents the orthogonal Q. In the in-phase I-orthogonal Q plane, there are 16 candidate signal points. (Of these 16 candidate signal points, one is the signal point transmitted by the transmitting device. This is why they are called "16 candidate signal points.")

[0609] In environments where direct waves are dominant, especially in LOS environments, Case 1: If the phase shifting units 205A and 205B in Figure 22 do not exist (i.e., if the phase shifting is not performed by the phase shifting units 205A and 205B in Figure 22) Let's consider this.

[0610] In the "first case," since no phase change is performed, it is possible to fall into a state like that shown in Figure 12(A). If the state shown in Figure 12(A) occurs, there are areas where the signal points are densely packed (closely separated), such as "signal points 1201 and 1202," "signal points 1203, 1204, 1205, and 1206," and "signal points 1207 and 1208," which may cause a decrease in the data reception quality in the receiving device shown in Figure 8.

[0611] To overcome this challenge, phase shifting units 205A and 205B are inserted in Figure 22. When phase shifting units 205A and 205B are inserted, symbol numbers i will have a mix of symbol numbers where the signal points are dense (close distance between signal points), as in Figure 12(A), and symbol numbers where the signal points are far apart, as in Figure 12(B). By introducing error correction codes to address this situation, high error correction capability can be achieved, resulting in high data reception quality in the receiving device shown in Figure 8.

[0612] Furthermore, in Figure 22, the "pilot symbol and preamble," which are used for channel estimation to demodulate (detect) data symbols, are not phase-shifted in the phase shifting sections 205A and 205B of Figure 22. This makes it possible to achieve a situation in the data symbols where "symbol number i has a mix of symbol numbers where the signal points are dense (close distance between signal points) as in Figure 12(A) and symbol numbers where the signal points are far apart as in Figure 12(B)."

[0613] However, even if phase shifting is performed on the pilot symbol and preamble, which are used for channel estimation to demodulate (detect) data symbols, in the phase shifting units 205A and 205B of Figure 22, it may still be possible to achieve a situation where, for each symbol number i, there is a mixture of symbol numbers where the signal points are densely packed (close distance between signal points) as shown in Figure 12(A), and symbol numbers where the signal points are far apart as shown in Figure 12(B). In this case, some condition must be added to the pilot symbol and preamble when performing phase shifting. For example, one could establish a separate rule from the phase shifting rule for data symbols and apply phase shifting to the pilot symbol and / or preamble. As an example, one could apply phase shifting with a period N to the data symbols regularly, and phase shifting with a period M to the pilot symbol and / or preamble regularly. (N and M are integers greater than or equal to 2.)

[0614] As previously mentioned, the phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. Let the baseband signal 208A be a function of symbol number i (where i is a non-negative integer), and be represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. The operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A characteristic of the phase shifting unit 209A is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), etc.). (In the case of Figure 22, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 4.)

[0615] Therefore, in the frame of Figure 4, the phase shifting unit 209A in Figure 22 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403).

[0616] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift." ...

[0617] As previously mentioned, the phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, performs a phase shift on the baseband signal 208B based on the control signal 200, and outputs the phase-shifted signal 210B. Let the baseband signal 208B be a function of symbol number i (where i is a non-negative integer), and be represented as y'(i). Then the phase-shifted signal 210B(y(i)) is given by y(i) = e j×η(i)It can be expressed as ×y'(i), where j is the imaginary unit. The operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A characteristic of the phase shifting unit 209B is that it performs phase shifting on symbols that exist in the frequency axis direction (it applies phase shifting to data symbols, pilot symbols, control information symbols, etc.). (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), etc.). (In the case of Figure 22, since the phase shifting unit 209B performs phase shifting on the baseband signal 208B, it will perform phase shifting on each symbol shown in Figure 5.)

[0618] Therefore, in the frame of Figure 5, the phase shifting unit 209B in Figure 22 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503).

[0619] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift." ...

[0620] Figure 13 shows a different frame configuration for the transmitted signal 108_A in Figure 1 compared to Figure 4. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0621] Figure 14 shows a different frame configuration for the transmitted signal 108_B in Figure 1 compared to Figure 5. Since a detailed explanation was given in Embodiment 1, this explanation will be omitted here.

[0622] When a symbol exists on carrier A at time $B in Figure 13, and a symbol exists on carrier A at time $B in Figure 14, the symbols on carrier A at time $B in Figure 13 and the symbols on carrier A at time $B in Figure 14 will be transmitted at the same time and on the same frequency. Note that the frame configurations in Figures 13 and 14 are merely examples.

[0623] Furthermore, the other symbols in Figures 13 and 14 correspond to the preamble signal 252 and control information symbol signal 253 in Figure 22. Therefore, if the other symbol 503 in Figure 14 is transmitting control information at the same time and on the same frequency (same carrier) as the other symbol 403 in Figure 13, then it will be transmitting the same data (same control information).

[0624] Although it is assumed that the receiving device will receive the frames in Figure 13 and Figure 14 simultaneously, the receiving device can still obtain the data transmitted by the transmitting device even if it receives only the frames in Figure 13 or only the frames in Figure 14.

[0625] The phase shifting unit 209A receives the baseband signal 208A and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208A based on the control signal 200, outputting the phase-shifted signal 210A. The baseband signal 208A is a function of symbol number i (where i is a non-negative integer), and is represented as x'(i). Then the phase-shifted signal 210A(x(i)) is given by x(i)=e j×ε(i)It can be expressed as ×x'(i), where j is the imaginary unit. Furthermore, the operation of the phase shifting unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209A is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 22, since the phase shifting unit 209A performs phase shifting on the baseband signal 208A, it will perform phase shifting on each symbol shown in Figure 13.)

[0626] Therefore, in the frame of Figure 13, the phase shifting unit 209A in Figure 22 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 403). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0627] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 403), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 401 or data symbol 402), the phase shifting unit 209A in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0628] Let Ω(i) represent the phase change value in the phase change section 209A. The baseband signal 208A is x'(i), and the signal 210A after phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds true.

[0629] For example, set the phase change value to equation (38). (Q is an integer greater than or equal to 2, and Q is the period of the phase change.) (j is the imaginary unit) However, equation (38) is merely an example and is not the only one.

[0630] For example, Ω(i) may be set to perform a phase change so that it has a period Q.

[0631] Alternatively, as shown in Figures 4 and 13, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. • For carrier 1 in Figures 4 and 13, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 4 and 13, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 4 and 13, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 4 and 13, the phase change value is given by equation (42), regardless of time. ...

[0632] The above is an example of the operation of the phase shifting unit 209A in Figure 22.

[0633] The phase shifting unit 209B receives the baseband signal 208B and the control signal 200 as inputs, and performs a phase shift on the baseband signal 208B based on the control signal 200, outputting the phase-shifted signal 210B. The baseband signal 208B is a function of symbol number i (where i is a non-negative integer), and is represented as y'(i). Then, the phase-shifted signal 210B(x(i)) is given by y(i) = e j×η(i) It can be expressed as ×y'(i), where j is the imaginary unit. Furthermore, the operation of the phase shifting unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) as described in Non-Patent Documents 2 and 3. A key feature of the phase shifting unit 209B is that it performs phase shifting on symbols located along the frequency axis (data symbols, pilot symbols, control information symbols, etc.). In this case, null symbols can also be considered targets for phase shifting. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preamble (other symbols), null symbols, etc.). However, even if phase shifting is performed on a null symbol, the signal before and after phase shifting remain the same (the common-mode component I is zero (0), and the quadrature component Q is zero (0)). Therefore, it is also possible to interpret that null symbols are not targets for phase shifting. (In the case of Figure 22, the phase shifting unit 209B performs phase shifting on the baseband signal 208B, so it will perform phase shifting on each symbol shown in Figure 14.)

[0634] Therefore, in the frame of Figure 14, the phase shifting unit 209B in Figure 22 performs a phase shift on all symbols from carrier 1 to carrier 36 at time $1 (in this case, all of which become other symbols 503). However, the handling of the phase shift of the null symbol 1301 is as previously explained.

[0635] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all of them become other symbols 503), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for the null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, pilot symbol 501 or data symbol 502), the phase shifting unit 209B in Figure 22 performs a phase shift. However, the handling of the phase shift for null symbol 1301 is as previously explained." ...

[0636] Let Δ(i) represent the phase change value in the phase change section 209B. The baseband signal 208B is y'(i), and the signal 210B after phase change is y(i). Therefore, y(i) = Δ(i) × y'(i) holds true.

[0637] For example, set the phase change value as given in equation (49). (R is an integer greater than or equal to 2, and R is the period of the phase change. It is preferable that the values ​​of Q and R in equation (38) are different.)

[0638] For example, Δ(i) may be set to perform a phase change so that it has a period R.

[0639] Alternatively, for example, in Figures 5 and 14, the same phase shift value may be applied to the same carrier, and a separate phase shift value may be set for each carrier. For example, this would be as follows. For carrier 1 in Figures 5 and 14, the phase change value is given by equation (39), regardless of time. • For carrier 2 in Figures 5 and 14, the phase change value is given by equation (40), regardless of time. • For carrier 3 in Figures 5 and 14, the phase change value is given by equation (41), regardless of time. • For carrier 4 in Figures 5 and 14, the phase change value is given by equation (42), regardless of time. ...

[0640] The above is an example of the operation of the phase shifting unit 209B shown in Figure 20.

[0641] The effects obtained by the phase shifting units 209A and 209B shown in Figure 22 will be explained.

[0642] The other symbols 403 and 503 in the frames of Figures 4 and 5, or the frames of Figures 13 and 14, are assumed to contain control information symbols. As previously explained, the other symbols 503 in Figure 5, at the same time and on the same frequency (same carrier) as the other symbols 403, transmit the same data (same control information) when transmitting control information.

[0643] Now, consider the following case.

[0644] Case 2: The control information symbol is transmitted using either antenna unit #A (109_A) or antenna unit #B (109_B) shown in Figure 1.

[0645] In the case of transmission as in "Case 2," since only one antenna transmits the control information symbols, the spatial diversity gain is smaller compared to the case where "both antenna unit #A (109_A) and antenna unit #B (109_B) are used to transmit the control information symbols." Therefore, in "Case 2," the data reception quality will be reduced even when received by the receiver in Figure 8. Consequently, in terms of improving data reception quality, it is better to "transmit the control information symbols using both antenna unit #A (109_A) and antenna unit #B (109_B)."

[0646] Case 3: The control information symbol is transmitted using both antenna section #...

Claims

1. It comprises a mapping unit, a signal processing unit, and a transmission unit. The mapping unit, in its operation, If the first precoding is enabled, multiple first symbols are generated by modulating the bit sequence. If the first precoding is not effective, the second and third symbols are generated by modulating the bit sequence. The signal processing unit, in its operation, If the first precoding is enabled, the first precoding is performed on the plurality of first symbols to generate a plurality of first precoded symbols, each of which is a weighted sum of the plurality of first symbols. If the first precoding is not effective, the second precoding is performed on the second and third symbols to generate a second precoded symbol which is a weighted sum of the second and third symbols, and a third precoded symbol which is a weighted sum of the second and third symbols. In operation, the transmitting unit The first precoded symbol, or the second precoded symbol and the third precoded symbol are transmitted. Each of the aforementioned plurality of first precoded symbols is mapped to a plurality of subcarriers that are different from each other. Transmitter.

2. The aforementioned transmitting unit uses OFDM (orthogonal frequency-division multiplexing) transmission mode. The transmitting device according to claim 1.

3. The first precode and the second precode are the same precode This is done based on the ing matrix. The transmitting device according to claim 1.

4. A transmission method performed by a transmitting device, If the first precoding is enabled, multiple first symbols are generated by modulating the bit sequence. If the first precoding is not effective, the first step is to generate a second symbol and a third symbol by modulating the bit sequence, If the first precoding is enabled, the first precoding is performed on the plurality of first symbols to generate a plurality of first precoded symbols, each of which is a weighted sum of the plurality of first symbols. If the first precoding is not effective, a second step is to perform the second precoding on the second symbol and the third symbol to generate a second precoded symbol which is a weighted sum of the second symbol and the third symbol, and a third precoded symbol which is a weighted sum of the second symbol and the third symbol. A third step of transmitting the first precoded symbol, or the second precoded symbol and the third precoded symbol, Includes, Each of the aforementioned plurality of first precoded symbols is mapped to a plurality of subcarriers that are different from each other. Sending method.

5. In the third step described above, the OFDM (orthogonal frequency-division multiplexing) transmission mode is used. The transmission method according to claim 4.

6. The first precoding and the second precoding are performed based on the same precoding matrix. The transmission method according to claim 4.

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