Transmitting device and transmitting method

Abstract

To provide a transmission device capable of improving a reception quality of data.SOLUTION: A transmission device comprises: a mapping part; a signal processing part; and a transmission part. The mapping part generates a plurality of first symbols in the case where a first pre-coding is valid, and generates a second symbol and a third symbol in the case where it is invalid. The signal processing part generates a plurality of first pre-coded symbols by executing each first pre-coding in the case where each first pre-coding is valid, and generates a second pre-coded symbol and a third pre-coded symbol by executing each second pre-coding in the case where it is invalid. The transmission part transmits the first pre-coded symbol, or the second pre-coded symbol and the third pre-coded symbol.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention particularly relates to a transmission device and a reception device that perform communication using multiple antennas.

Background Art

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

[0003] FIG. 17 shows an example of the configuration of a transmission device based on the DVB-NGH (Digital Video Broadcasting - Next Generation Handheld) standard when the number of transmission antennas is 2 and the number of transmission modulation signals (transmission streams) is 2, as described in Non-Patent Document 1. In the transmission device, data 003 encoded by an encoding unit 002 is divided by a distribution unit 004 into data 005A and data 005B. Data 005A is subjected to an interleaving process by an interleaver 004A and a mapping process by a mapping unit 006A. Similarly, data 005B is subjected to an interleaving process by an interleaver 004B and a mapping process by a mapping unit 006B. Weighted combining units 008A and 008B take the mapped signals 007A and 007B as inputs and perform weighted combining respectively, generating weighted combined signals 009A and 016B. The weighted combined signal 016B then undergoes a phase change. Then, by radio units 010A and 010B, for example, processes related to OFDM (orthogonal frequency division multiplexing), frequency conversion, amplification, etc. are performed, and transmission signals 011A are transmitted from antenna 012A and transmission signals 011B are transmitted from antenna 012B.

[0004] In the case of the conventional configuration, the transmission of single-stream signals together is not considered. In such a case, it is considered that it is advisable to introduce a new transmission method, particularly for improving the reception quality of data in a single-stream receiver.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention relates to a transmission method when transmitting a single-stream signal and a multi-stream signal together using a multi-carrier transmission method such as the OFDM method, thereby improving the reception quality of single-stream data and improving the reception quality of multi-stream data in a propagation environment including LOS (line-of sight).

Means for Solving the Problems

[0007] The transmission apparatus according to the present invention includes a mapping unit, a signal processing unit, and a transmission unit. In operation, when the first precoding is effective, the mapping unit generates a plurality of first symbols by modulating a bit sequence. When the first precoding is not effective, the mapping unit generates a second symbol and a third symbol by modulating the bit sequence. In operation, when the first precoding is effective, the signal processing unit executes the first precoding on the plurality of first symbols to generate a plurality of first precoded symbols that are weighted sums of the plurality of first symbols respectively. When the first precoding is not effective, the signal processing unit executes a second precoding on the second symbol and the third symbol to generate a second precoded symbol that is a weighted sum of the second symbol and the third symbol, and a third precoded symbol that is a weighted sum of the second symbol and the third symbol. In operation, the transmission unit transmits the first precoded symbols, or the second precoded symbol and the third precoded symbol.

[0008] The transmission method according to the present invention is a transmission method performed by a transmission device. When the first precoding is effective, a plurality of first symbols are generated by modulating a bit sequence. When the first precoding is not effective, a second symbol and a third symbol are generated by modulating the bit sequence in a first step. When the first precoding is effective, a plurality of first precoded symbols, which are weighted additions of the plurality of first symbols respectively, are generated by performing the first precoding on the plurality of first symbols. When the first precoding is not effective, a second precoded symbol, which is a weighted addition of the second symbol and the third symbol, and a third precoded symbol, which is a weighted addition of the second symbol and the third symbol, are generated by performing a second precoding on the second symbol and the third symbol in a second step. A third step of transmitting the first precoded symbols, or the second precoded symbol and the third precoded symbol is included.

[0009] The receiving apparatus according to the present invention includes a receiving unit that receives a signal transmitted according to a predetermined transmission method, and a demodulating unit that demodulates the received signal. The predetermined transmission method performs precoding processing on a first baseband signal and a second baseband signal to generate a first precoded signal and a second precoded signal, inserts a pilot signal into the first precoded signal, sets the symbol number as i, and when i is an integer of 0 or more, performs a phase change of i×Δλ on the second precoded signal, inserts a pilot signal into the second precoded signal after the phase change, performs a phase change on the second precoded signal after the phase change and the pilot signal insertion, where Δλ is the difference in the phase change amount applied to two consecutive symbols with consecutive symbol numbers, and satisfies π / 2 radians < Δλ < π radians, or π radians < Δλ < 3π / 2 radians, and performs processing. The demodulating unit performs a demodulation process corresponding to the phase change.

[0010] The receiving method according to the present invention receives a signal transmitted according to a predetermined transmission method. In the predetermined transmission method, precoding processing is performed on 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 into the first precoded signal, sets the symbol number as i, and when i is an integer of 0 or more, performs a phase change of i×Δλ on the second precoded signal, inserts a pilot signal into the second precoded signal after the phase change, performs a phase change on the second precoded signal after the phase change and the pilot signal insertion, where Δλ is the difference in the phase change amount applied to two consecutive symbols with consecutive symbol numbers, and satisfies π / 2 radians < Δλ < π radians, or π radians < Δλ < 3π / 2 radians, and the processing is performed. A demodulation process corresponding to the phase change is performed on the received signal to demodulate it.

Effect of the Invention

[0011] According to the present invention as described above, since it is possible to improve the reception quality of single-stream data and also improve the reception quality of multi-stream data in a propagation environment including LOS (line-of sight), it is possible to provide a high-quality communication service.

Brief Description of the Drawings

[0012]

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DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

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

[0015] FIG. 1 shows an example of the configuration of a transmission apparatus such as a base station, an access point, or a broadcasting station in this embodiment. The error correction encoder 102 takes the data 101 and the control signal 100 as inputs, and performs error correction encoding based on the information on the error correction code included in the control signal 100 (for example, error correction code information, code length (block length), coding rate), and outputs the encoded data 103. Note that the error correction encoder 102 may include an interleaver, and if it includes an interleaver, it may rearrange the data after encoding and output the encoded data 103.

[0016] The mapping unit 104 takes the encoded data 103 and the control signal 100 as inputs, performs mapping corresponding to the modulation method based on the information on the modulation signal included in the control signal 100, and outputs the mapped signal (baseband signal) 105_1 and the mapped signal (baseband signal) 105_2. Note that 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. At this time, the first sequence and the second sequence are different.

[0017] The signal processing unit 106 takes as inputs the signals 105_1 and 105_2 after mapping, the signal group 110, and the control signal 100, performs signal processing based on the control signal 100, and outputs the signals 106_A and 106_B after signal processing. At this time, the signal 106_A after signal processing is expressed as u1(i), and the signal 106_B after signal processing is expressed as u2(i) (where i is the symbol number, for example, i is an integer greater than or equal to 0). Note that the signal processing will be described later with reference to FIG. 2.

[0018] The wireless unit 107_A takes as inputs the signal 106_A after signal processing and the control signal 100, performs processing on the signal 106_A after signal processing based on the control signal 100, and outputs the transmission signal 108_A. Then, the transmission signal 108_A is output as radio waves from the antenna unit #A (109_A).

[0019] Similarly, the wireless unit 107_B takes as inputs the signal 106_B after signal processing and the control signal 100, performs processing on the signal 106_B after signal processing based on the control signal 100, and outputs the transmission signal 108_B. Then, the transmission signal 108_B is output as radio waves from the antenna unit #B (109_B).

[0020] The antenna unit #A (109_A) takes the control signal 100 as an input. At this time, based on the control signal 100, processing is performed on the transmission signal 108_A and it is output as radio waves. However, the antenna unit #A (109_A) does not necessarily need to take the control signal 100 as an input.

[0021] Similarly, the antenna unit #B (109_B) takes the control signal 100 as an input. At this time, based on the control signal 100, processing is performed on the transmission signal 108_B and radio waves are output. However, the antenna unit #B (109_B) does not necessarily need to take the control signal 100 as an input.

[0022] Note that the control signal 100 may be generated based on the information transmitted by the device that is the communication partner in FIG. 1, or the device in FIG. 1 may include an input unit and may be generated based on the information input from the input unit of the device.

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

[0024] The weighted synthesis unit (precoding unit) 203 will perform the following operations.

[0025]

Equation

[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 be real numbers) Note that i is the symbol number.

[0027] Then, the phase change unit 205B takes the weighted synthesized signal 204B and the control signal 200 as inputs, and based on the control signal 200, performs a phase change on the weighted synthesized signal 204B and outputs the phase-changed signal 206B. Let the phase-changed signal 206B be represented 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 change unit 205B will be described. In the phase change unit 205B, for example, it is assumed that a phase change of y(i) is performed on z2’(i). Therefore, it can be expressed as z2(i) = y(i) × z2’(i). (i is the symbol number (i is an integer greater than or equal to 0))

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

[0030]

Equation

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

[0032]

Equation

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

[0034] In Equation (3), the phase change value is not limited to Equation (2), and for example, a method of changing the phase periodically and regularly can be considered.

[0035] (Preliminary coding) matrices in Formula (1) and Formula (3) [Number] Let it be. For example, as the matrix F, the following matrices can be considered.

[0036] [Number] Or [Number] Or [Number] Or [Number] Or [Number] Or [Number] Or [Number] Or [Number]

[0037] In addition, in Formula (5), Formula (6), Formula (7), Formula (8), Formula (9), Formula (10), Formula (11), and Formula (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] or [Number] or [Number] or [Number] or [Number] or [Number] or [Number] or [Number]

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

Math

Math

Math

Math

Math

Math

Math

[0039] However, θ 11 (i), θ 21 (i), λ(i) is a function of i (symbol number) (real number), λ is, for example, a fixed value (real number) (not necessarily a fixed value), α may be a real number or an imaginary number, β may be a real number or an imaginary number. However, α is not 0 (zero). And β is also not 0 (zero). Also, θ 11 , θ 21 is a real number.

[0040] Also, each embodiment of this specification can be implemented using precoding matrices other than these. or

Math

Math

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

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

[0043] Similarly, the insertion unit 207B takes as inputs the signal 206B after phase change, the pilot symbol signal (pb(t) (251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200, and outputs a baseband signal 208B based on the frame configuration according to the information on the frame configuration included in the control signal 200.

[0044] The phase change unit 209B takes as inputs the baseband signal 208B and the control signal 200, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs a signal 210B after phase change. Let the baseband signal 208B be a function of the symbol number i (i is an integer equal to or greater than 0) and be represented as x’(i). Then, the signal 210B (x(i)) after phase change can be represented as x(i) = e j×ε(i) × x’(i). (j is the imaginary unit)

[0045] Incidentally, as will be described later, the operation of the phase change unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209B is that phase change is performed on symbols existing in the frequency axis direction (phase change is applied to data symbols, pilot symbols, control information symbols, etc.).

[0046] FIG. 3 is an example of the configuration of the radio units 107_A and 107_B in FIG. 1. The serial-parallel conversion unit 302 takes as inputs the signal 301 and the control signal 300 (corresponding to the control signal 100 in FIG. 1), performs serial-parallel conversion based on the control signal 300, and outputs the signal 303 after serial-parallel conversion.

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

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

[0049] (For example, when the signal 301 is the signal 106_A after signal processing in FIG. 1, the modulated signal 307 corresponds to the transmission signal 108_A in FIG. 1. Also, when the signal 301 is the signal 106_B after signal processing in FIG. 1, the modulated signal 307 corresponds to the transmission signal 108_B in FIG. 1.)

[0050] FIG. 4 shows the frame configuration of the transmission signal 108_A in FIG. 1. In FIG. 4, the horizontal axis represents frequency (carrier), and the vertical axis represents time. Since a multi-carrier transmission method such as OFDM is used, symbols exist in the carrier direction. And in FIG. 4, symbols from carrier 1 to carrier 36 are shown. Also, in FIG. 4, symbols from time $1 to time $11 are shown.

[0051] 401 in FIG. 4 is a pilot symbol (corresponding to the pilot signal 251A (pa(t)) in FIG. 2), 402 is a data symbol, and 403 is other symbols. At this time, the pilot symbol is, for example, a symbol of PSK (Phase Shift Keying), and it is a symbol for a receiving device that receives this frame to perform channel estimation (estimation of propagation path fluctuations) and estimation of frequency offset and phase fluctuations. For example, it is preferable that the transmission device in FIG. 1 and the receiving device that receives the frame in FIG. 4 share the transmission method of the pilot symbol.

[0052] Incidentally, the signal 201A after mapping (the signal 105_1 after mapping in FIG. 1) is named "Stream #1", and the signal 201B after mapping (the signal 105_2 after mapping in FIG. 1) is named "Stream #2". Note that this point shall be the same in the following description.

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

[0054] Let other symbols 403 be symbols corresponding to the preamble signal 242 and the control information symbol signal 253 in FIG. 2. (However, other symbols may include symbols other than the preamble and control information symbols.) At this time, the preamble may transmit (control) data, and may be composed of symbols for signal detection, symbols for frequency synchronization and time synchronization, symbols for channel estimation (symbols for estimating propagation path fluctuations), and the like. And the control information symbol is a symbol containing control information for the receiving device that has received the frame of FIG. 4 to realize demodulation and decoding of data symbols.

[0055] For example, carriers 1 to 36 from time $1 to time 4 in FIG. 4 are other symbols 403. And carriers 1 to 11 at time $5 are data symbols 402. Thereafter, carrier 12 at time $5 is a pilot symbol 401, carriers 13 to 23 at time $5 are data symbols 402, carrier 24 at time $5 is a pilot symbol 401, ···, carriers 1 and 2 at time $6 are data symbols 402, carrier 3 at time $6 is a pilot symbol 401, ···, carrier 30 at time $11 is a pilot symbol 401, and carriers 31 to 36 at time $11 are data symbols 402.

[0056] FIG. 5 shows the frame configuration of the transmission signal 108_B in FIG. 1. In FIG. 5, the horizontal axis is frequency (carrier) and the vertical axis is time. Since a multi-carrier transmission method such as OFDM is used, symbols exist in the carrier direction. And in FIG. 5, symbols of carriers 1 to 36 are shown. Also, in FIG. 5, symbols from time $1 to time $11 are shown.

[0057] 501 in Fig. 5 indicates a pilot symbol (corresponding to the pilot signal 251B (pb(t)) in Fig. 2), 502 indicates a data symbol, and 503 indicates other symbols. At this time, the pilot symbol is, for example, a symbol of PSK, and it is a symbol for a receiving device that receives this frame to perform channel estimation (estimation of propagation path fluctuations), frequency offset and phase fluctuation estimation. For example, it is preferable that the transmitting device in Fig. 1 and the receiving device that receives the frame in Fig. 5 share the transmission method of the pilot symbol.

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

[0059] It is assumed that the other symbols 503 are symbols corresponding to the preamble signal 252 and the control information symbol signal 253 in Fig. 2. (However, the other symbols may include symbols other than the preamble and the control information symbol.) At this time, the preamble may transmit (control) data, and is composed of symbols for signal detection, symbols for frequency synchronization and time synchronization, symbols for channel estimation (symbols for estimating propagation path fluctuations), etc. And the control information symbol is a symbol including the control information for the receiving device that receives the frame in Fig. 5 to realize demodulation and decoding of the data symbol.

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

[0061] When there is a symbol for carrier A at time $B in FIG. 4 and there is a symbol for carrier A at time $B in FIG. 5, the symbol for carrier A at time $B in FIG. 4 and the symbol for carrier A at time $B in FIG. 5 will be transmitted at the same time and the same frequency. Note that the frame configuration is not limited to FIGS. 4 and 5. FIGS. 4 and 5 are merely examples of the frame configuration.

[0062] Moreover, the other symbols in FIGS. 4 and 5 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 5 at the same time and the same frequency (same carrier) as the other symbol 403 in FIG. 4 is transmitting control information, it is transmitting the same data (same control information).

[0063] Although it is assumed that the receiving device will receive the frames of FIGS. 4 and 5 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 4 or only the frame of FIG. 5.

[0064] FIG. 6 shows an example of the configuration of a part related to control information generation for generating the control information symbol signal 253 in FIG. 2.

[0065] The control information mapping unit 602 takes data 601 related to control information and a control signal 600 as inputs, performs mapping on the data 601 related to control information in a modulation method based on the control signal 600, and outputs a signal 603 after mapping for control information. Note that the signal 603 after mapping for control information corresponds to the control information symbol signal 253 in FIG. 2.

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

[0067] The distribution unit 702 takes a transmission signal 701 as an input, performs distribution, and outputs transmission signals 703_1, 703_2, 703_3, and 703_4.

[0068] The multiplication unit 704_1 takes the transmission signal 703_1 and the control signal 700 as inputs, multiplies the transmission signal 703_1 by a multiplication coefficient based on the information of the multiplication coefficient included in the control signal 700, and outputs a signal 705_1 after multiplication. The signal 705_1 after multiplication is output as a radio wave from the antenna 706_1.

[0069] Assuming the transmission signal 703_1 is Tx1(t) (t: time) and the multiplication coefficient is W1 (W1 can be defined as a complex number and thus can also be a real number), the signal 705_1 after multiplication can be expressed as Tx1(t) × W1.

[0070] The multiplication unit 704_2 takes the transmission signal 703_2 and the control signal 700 as inputs, multiplies the transmission signal 703_2 by a multiplication coefficient based on the information of the multiplication coefficient included in the control signal 700, and outputs a signal 705_2 after multiplication. The signal 705_2 after multiplication is output as a radio wave from the antenna 706_2.

[0071] Assuming that the transmission signal 703_2 is Tx2(t) and the multiplication coefficient is W2 (W2 can be defined as a complex number and thus may also be a real number), the signal 705_2 after multiplication can be expressed as Tx2(t) × W2.

[0072] The multiplication unit 704_3 takes the transmission signal 703_3 and the control signal 700 as inputs. Based on the information of the multiplication coefficient included in the control signal 700, it multiplies the transmission signal 703_3 by the multiplication coefficient and outputs the signal 705_3 after multiplication. The signal 705_3 after multiplication is output from the antenna 706_3 as a radio wave.

[0073] Assuming that the transmission signal 703_3 is Tx3(t) and the multiplication coefficient is W3 (W3 can be defined as a complex number and thus may also be a real number), the signal 705_3 after multiplication can be expressed as Tx3(t) × W3.

[0074] The multiplication unit 704_4 takes the transmission signal 703_4 and the control signal 700 as inputs. Based on the information of the multiplication coefficient included in the control signal 700, it multiplies the transmission signal 703_4 by the multiplication coefficient and outputs the signal 705_4 after multiplication. The signal 705_4 after multiplication is output from the antenna 706_4 as a radio wave.

[0075] Assuming that the transmission signal 703_4 is Tx4(t) and the multiplication coefficient is W4 (W4 can be defined as a complex number and thus may also be a real number), the signal 705_4 after multiplication can be expressed as Tx4(t) × W4.

[0076] It should be noted that "the absolute values of W1, W2, W3, and W4 are equal" may also be the case. At this time, it corresponds to the occurrence of a phase change. (Of course, the absolute values of W1, W2, W3, and W4 do not necessarily have to be equal.)

[0077] Also, in Fig. 7, the antenna section is described by taking an example where it is composed of four antennas (and four multiplication units). However, the number of antennas is not limited to four, and it may be composed of two or more antennas.

[0078] When the configuration of the antenna unit #A (109_A) in FIG. 1 is as shown in FIG. 7, the transmission signal 701 corresponds to the transmission signal 108_A in FIG. 1. Also, when the configuration of the antenna unit #B (109_B) in FIG. 1 is as shown in FIG. 7, the transmission signal 701 corresponds to the transmission signal 108_B in FIG. 1, which is equivalent to the transmission signal 108_B in FIG. 1. However, the antenna unit #A (109_A) and the antenna unit #B (109_B) do not necessarily have to be configured as shown in FIG. 7. As described previously, the antenna unit may not receive the control signal 100.

[0079] FIG. 8 shows an example of the configuration of a receiving device that receives the modulation signal when the transmitting device in FIG. 1 transmits a transmission signal having the frame configurations of FIGS. 4 and 5, for example.

[0080] The radio unit 803X takes the received signal 802X received by the antenna unit #X (801X) as an input, performs processes such as frequency conversion and Fourier transform, and outputs a baseband signal 804X.

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

[0082] Note that although FIG. 8 shows the antenna unit #X (801X) and the antenna unit #Y (801Y) as being configured to receive the control signal 810, they may also be configured not to receive the control signal 810. The operation when the control signal 810 is present as an input will be described in detail later.

[0083] Incidentally, FIG. 9 shows the relationship between the transmitting device and the receiving device. The antennas 901_1 and 901_2 in FIG. 9 are transmitting antennas, and the antenna 901_1 in FIG. 9 corresponds to the antenna unit #A (109_A) in FIG. 1. And the antenna 901_2 in FIG. 9 corresponds to the antenna unit #B (109_B) in FIG. 1.

[0084] The antennas 902_1 and 902_2 in FIG. 9 are receiving antennas, and the antenna 902_1 in FIG. 9 corresponds to the antenna unit #X (801X) in FIG. 8. The antenna 902_2 in FIG. 9 corresponds to the antenna unit #Y (801Y) in FIG. 8.

[0085] As shown in FIG. 9, let the signal transmitted from the transmitting antenna 901_1 be u1(i), the signal transmitted from the transmitting antenna 901_2 be u2(i), the signal received by the receiving antenna 902_1 be r1(i), and the signal received by the receiving antenna 902_2 be r2(i). Here, i represents the symbol number and is, for example, an integer of 0 or more.

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

[0087]

Equation

[0088] Here, n1(i) and n2(i) are noise.

[0089] The channel estimation unit 805_1 for the modulation signal u1 in FIG. 8 takes the baseband signal 804X as an input, and uses the preamble and / or pilot symbols in FIGS. 4 and 5 to estimate the channel of the modulation signal u1, that is, to estimate h11(i) in Equation (37), and outputs a channel estimation signal 806_1.

[0090] The channel estimation unit 805_2 for the modulation signal u2 takes the baseband signal 804X as an input, and uses the preamble and / or pilot symbols in FIGS. 4 and 5 to estimate the channel of the modulation signal u2, that is, to estimate h12(i) in Equation (37), and outputs a channel estimation signal 806_2.

[0091] The channel estimator 807_1 of the modulation signal u1 takes the baseband signal 804Y as an input, and estimates the channel of the modulation signal u1, that is, h21(i) in Equation (37), using the preambles and / or pilot symbols in FIGS. 4 and 5, and outputs a channel estimation signal 808_1.

[0092] The channel estimator 807_2 of the modulation signal u2 takes the baseband signal 804Y as an input, and estimates the channel of the modulation signal u2, that is, h22(i) in Equation (37), using the preambles and / or pilot symbols in FIGS. 4 and 5, and outputs a channel estimation signal 808_2.

[0093] The control information decoder 809 takes the baseband signals 804X and 804Y as inputs, demodulates and decodes the control information included in the "other symbols" in FIGS. 4 and 5, and outputs a control signal 810 including the control information.

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

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

[0096] FIG. 10 shows an example of the configuration of the antenna unit #X (801X) and the antenna unit #Y (801Y) in FIG. 8. (This is an example in which the antenna unit #X (801X) and the antenna unit #Y (801Y) are composed of a plurality of antennas.)

[0097] The multiplication unit 1003_1 takes the received signal 1002_1 received by the antenna 1001_1 and the control signal 1000 as inputs, multiplies the received signal 1002_1 by a multiplication coefficient based on the information of the multiplication coefficient included in the control signal 1000, 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 thus can also be a real number), the multiplied signal 1004_1 is expressed as Rx1(t) × D1.

[0099] The multiplication unit 1003_2 takes the received signal 1002_2 received by the antenna 1001_2 and the control signal 1000 as inputs, multiplies the received signal 1002_2 by a multiplication coefficient based on the information of the multiplication coefficient included in the control signal 1000, and outputs the multiplied signal 1004_2.

[0100] If the received signal 1002_2 is Rx2(t) and the multiplication coefficient is D2 (D2 can be defined as a complex number and thus can also be a real number), the multiplied signal 1004_2 is expressed as Rx2(t) × D2.

[0101] The multiplication unit 1003_3 takes the received signal 1002_3 received by the antenna 1001_3 and the control signal 1000 as inputs, multiplies the received signal 1002_3 by a multiplication coefficient based on the information of the multiplication coefficient included in the control signal 1000, and outputs the multiplied signal 1004_3.

[0102] If the received signal 1002_3 is Rx3(t) and the multiplication coefficient is D3 (D3 can be defined as a complex number and thus can also be a real number), the multiplied signal 1004_3 is expressed as Rx3(t) × D3.

[0103] The multiplication unit 1003_4 takes the received signal 1002_4 received by the antenna 1001_4 and the control signal 1000 as inputs, multiplies the received signal 1002_4 by the multiplication coefficient based on the information of the multiplication coefficient included in the control signal 1000, and outputs the multiplied signal 1004_4.

[0104] If the received signal 1002_4 is denoted as Rx4(t) and the multiplication coefficient is denoted as D4 (D4 can be defined as a complex number and thus may also be a real number), the multiplied signal 1004_4 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 inputs, combines the multiplied signals 1004_1, 1004_2, 1004_3, and 1004_4, and outputs the combined signal 1006. Note that the combined signal 1006 can be expressed as Rx1(t)×D1 + Rx2(t)×D2 + Rx3(t)×D3 + Rx4(t)×D4.

[0106] In FIG. 10, an example is described where the antenna unit is composed of four antennas (and four multiplication units), but the number of antennas is not limited to four, and it may be composed of two or more antennas.

[0107] When the configuration of the antenna unit #X (801X) in FIG. 8 is the same as that in FIG. 10, the received signal 802X corresponds to the combined signal 1006 in FIG. 10, and the control signal 710 corresponds to the control signal 1000 in FIG. 10. Also, when the configuration of the antenna unit #Y (801Y) in FIG. 8 is the same as that in FIG. 10, the received signal 802Y corresponds to the combined signal 1006 in FIG. 10, and the control signal 710 corresponds to the control signal 1000 in FIG. 10. However, the antenna unit #X (801X) and the antenna unit #Y (801Y) do not necessarily have the same configuration as that in FIG. 10, and as described above, the antenna unit does not necessarily take the control signal 710 as an input.

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

[0109] Next, as shown in FIG. 1, the signal processing unit 106 of the transmission device inserts the phase change unit 205B and the phase change unit 209B as shown in FIG. 2. The features and the effects at that time will be described.

[0110] As described with reference to FIGS. 4 and 5, for the mapped signal s1(i) (201A) obtained by mapping using the first sequence (where i is the symbol number and i is an integer of 0 or more) and the mapped signal s2(i) (201B) obtained by mapping using the second sequence, precoding (weighted synthesis) is performed, and phase change is performed on one of the obtained weighted synthesized signals 204A and 204B by the phase change unit 205B. Then, the weighted synthesized signal 204A and the phase-changed signal 206B will be transmitted at the same frequency and at the same time. Therefore, in FIGS. 4 and 5, phase change is performed on the data symbol 502 in FIG. 5. (In the case of FIG. 2, since the phase change unit 205B performs the operation on the weighted synthesized signal 204B, phase change is performed on the data symbol 502 in FIG. 5. When performing phase change on the weighted synthesized signal 204A, phase change is performed on the data symbol 402 in FIG. 4. This point will be described later.)

[0111] For example, FIG. 11 extracts carriers 1 to 5 and times $4 to $6 from the frame of FIG. 5. Similar to FIG. 5, 501 is a pilot symbol, 502 is a data symbol, and 503 is another 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 a 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) ", 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) ".

[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 characteristic point of the phase change unit 205B. Note that 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), (carrier 5, time $6) which are the objects of phase change in Fig. 11, and for "the same carrier, the same time", as shown in Fig. 4, data carriers are arranged. That is, in Fig. 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, the data symbols performing MIMO transmission (transmitting multiple streams) are the objects of phase change of the phase change unit 205B.)

[0116] Note that as an example of the phase change applied by the phase change unit 205B to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (2). (However, the phase change method applied to the data symbol is not limited to this.)

[0117] By doing so, in an environment where the direct wave is dominant, especially in the LOS environment, it is possible to obtain the effect that the reception quality of data in the receiving device of the data symbol performing MIMO transmission (transmitting multiple streams) is improved. This effect will be explained.

[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 also 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. (Among the 16 candidate signal points, one 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] Note that 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 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)" can be realized.

[0124] However, for "pilot symbols, preambles", etc. that are used for channel estimation to demodulate (detect) data symbols, even if phase change is performed in the phase change unit 205B of FIG. 2, there may be a case where "in data symbols, a symbol number with a dense signal point (a short distance between signal points) as shown in FIG. 12(A) and a symbol number with a long distance between signal points as shown in FIG. 12(B) coexist". In this case, some conditions must be added to the pilot symbols and preambles, and phase change must be performed. For example, a rule different from the rule for phase change of data symbols can be set, and a method of "performing phase change on pilot symbols and / or preambles" can be considered. As an example, there is a method of regularly performing phase change with a period N on data symbols and regularly performing phase change with a period M on pilot symbols and / or preambles. (N and M are integers of 2 or more.)

[0125] As described above, the phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after phase change. Let the baseband signal 208B be a function of the symbol number i (where i is an integer of 0 or more) and be represented as x'(i). Then, the signal 210B (x(i)) after phase change is x(i)=e j×ε(i)It can be expressed as ×x’(i) (j is the imaginary unit). As for the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on 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 FIG. 2, since the phase change unit 209B performs phase change on the baseband signal 208B, phase change is performed on each symbol described in FIG. 5. When performing phase change on the baseband signal 208A in FIG. 2, phase change is performed on each symbol described in FIG. 4. This point will be described later.)

[0126] Therefore, in the frame of FIG. 5, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 503), the phase change unit 209B in FIG. 2 performs phase change.

[0127] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all become other symbols 503), the phase change unit 209B in FIG. 2 performs phase change." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all become other symbols 503), the phase change unit 209B in FIG. 2 performs phase change." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all become other symbols 503), the phase change unit 209B in FIG. 2 performs phase change." "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." "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." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change." "For all symbols from carrier 1 to carrier 36 at time $11 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 2 performs a phase change." ···

[0128] Figure 13 shows a frame configuration different from that of Figure 4 of the transmission signal 108_A in Figure 1. In Figure 13, those that operate in the same manner as in Figure 4 are given the same numbers. In Figure 13, the horizontal axis is frequency (carrier) and the vertical axis is time. Similar to Figure 4, since a multi-carrier transmission method such as OFDM is used, symbols exist in the carrier direction. And in Figure 13, similar to Figure 4, the symbols from carrier 1 to carrier 36 are shown. Also, in Figure 13, similar to Figure 4, the symbols from time $1 to time $11 are shown.

[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] It is assumed that the null symbol 1301 has an in-phase component I of zero (0) and a quadrature component Q of zero (0). (Here, it is called a "null symbol", but this is not limited to this naming.)

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

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

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

[0134] It is assumed that the null symbol 1301 has an in-phase component I of zero (0) and a quadrature component Q of zero (0). (Here, it is called a "null symbol", but this is not the only way of calling it.)

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

[0136] When there is a symbol at carrier A and time $B in FIG. 13 and there is a symbol at carrier A and time $B in FIG. 14, the symbol at carrier A and time $B in FIG. 13 and the symbol at carrier A and time $B in FIG. 14 will be transmitted at the same time and the same frequency. Note that the frame configurations of FIGS. 13 and 14 are merely examples.

[0137] And the other symbols in FIGS. 13 and 14 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 14 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 13 transmits control information, it transmits the same data (the same control information).

[0138] It is assumed that the receiving device will receive the frame in FIG. 13 and the frame in FIG. 14 simultaneously. However, even if the receiving device receives only the frame in FIG. 13 or only the frame in FIG. 14, it is possible for the receiving device to obtain the data transmitted by the transmitting device.

[0139] The phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B 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 210B (x(i)) after the phase change can be expressed as x(i) = e j×ε(i) ×x'(i). (j is the imaginary unit) And as the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it is the point of performing a phase change on the symbols existing in the frequency axis direction (performing a phase change on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by the symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if a phase change is performed on a null symbol, the signal before the phase change and the signal after the phase change are the same (the in-phase 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 objects of phase change. (In the case of FIG. 2, since the phase change unit 209B performs a phase change on the baseband signal 208B, a phase change will be performed on each symbol described in FIG. 14. When performing a phase change on the baseband signal 208A in FIG. 2, a phase change will be performed on each symbol described in FIG. 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, 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 previously." "For all symbols from carrier 1 to carrier 36 at time $8 (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 previously." "For all symbols from carrier 1 to carrier 36 at time $9 (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 previously." "For all symbols from carrier 1 to carrier 36 at time $10 (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 previously." "For all symbols from carrier 1 to carrier 36 at time $11 (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 previously." ···

[0142] Let the phase change value in the phase change unit 209B be represented as Ω(i). The baseband signal 208B is x’(i), and the signal 210B after the phase change is x(i). Therefore, x(i) = Ω(i) × x’(i) holds."

[0143] For example, set the value of the phase change as follows. (Q is an integer of 2 or more, 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 as to have a period Q.

[0146] Also, for example, in FIGS. 5 and 14, the same phase change value may be given to the same carrier, and the phase change value may be set for each carrier. For example, it may be as follows. · For carrier 1 in FIGS. 5 and 14, regardless of time, the phase change value is

Number

Number

Number

Number

[0147] The above is an example of the operation of the phase change unit 209B in FIG. 2.

[0148] The effects obtained by the phase change unit 209B in FIG. 2 will be described.

[0149] Assume that other symbols 403 and 503, such as "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14", contain control information symbols. As previously explained, when other symbol 503 in FIG. 5 at the same time and with the same frequency (the same carrier) as other symbol 403 is transmitting control information, it is transmitting the same data (the same control information).

[0150] Now, consider the following cases.

[0151] Case 2: The control information symbol is transmitted using either one of the antenna units, i.e., antenna unit #A (109_A) or antenna unit #B (109_B) in FIG. 1.

[0152] When transmitted as in "Case 2", since the number of antennas transmitting the control information symbol is 1, the spatial diversity gain is smaller compared to the case of "transmitting the control information symbol using both antenna unit #A (109_A) and antenna unit #B (109_B)". Therefore, when receiving at the receiving device in FIG. 8 in the case of "Case 2", the reception quality of the data will deteriorate. Thus, in terms of improving the reception quality of the data, it is better to "transmit the control information symbol 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 unit #A (109_A) and antenna unit #B (109_B) in FIG. 1. However, no phase change is performed by the phase change unit 209B in FIG. 2.

[0154] When transmitted as in "Case 3", since the modulated signal transmitted from antenna unit #A109_A and the modulated signal transmitted from antenna unit #B109_B are the same (or have a specific phase shift), depending on the radio wave propagation environment, the receiving device in Fig. 8 may have a very poor received signal, and both modulated signals may be affected by the same multipath. As a result, there is a problem that the reception quality of data deteriorates in the receiving device of Fig. 8.

[0155] To mitigate this problem, in Fig. 2, a phase change unit 209B is provided. As a result, the phase is changed in the time or frequency direction, so the possibility of a poor received signal can be reduced in the receiving device of Fig. 8. In addition, since it is highly likely that there is a difference between the influence of multipath received by the modulated signal transmitted from antenna unit #A109_A and the influence of multipath received by the modulated signal transmitted from antenna unit #B109_B, there is a high possibility of obtaining a diversity gain, and thus the reception quality of data will be improved in the receiving device of Fig. 8.

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

[0157] In addition to control information symbols, other symbols 403 and other symbols 503 include, for example, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) for demodulating and decoding control information symbols. Also, the "frames of Figs. 4 and 5" or the "frames of Figs. 13 and 14" include pilot symbols 401 and 501, and by using these, it becomes possible to demodulate and decode control information symbols with higher accuracy.

[0158] In "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14", multiple streams are being transmitted (performing MIMO transmission) using the same frequency (band) and the same time by data symbol 402 and data symbol 502. To demodulate these data symbols, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) included in other symbol 403 and other symbol 503 are used.

[0159] At this time, as described above, "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) included in other symbol 403 and other symbol 503" are having their phases changed by phase change unit 209B.

[0160] In such a situation, if this process is not reflected in data symbol 402 and data symbol 502 (in the case of the above description, with respect to data symbol 502), when the receiving device demodulates and decodes data symbol 402 and data symbol 502, it is necessary to perform demodulation and decoding that reflects the process for the phase change performed by phase change unit 209B, and that process is likely to become complex. (Since "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variations) included in other symbol 403 and other symbol 503" are having their phases changed by phase change unit 209B)

[0161] However, as shown in FIG. 2, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, with respect to data symbol 502) in phase change section 209B, at the receiving device, the channel estimation signal (propagation path fluctuation estimation signal) estimated using "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations)" included in other symbol 403 and other symbol 503 has the advantage that data symbol 402 and data symbol 502 can be simply demodulated and decoded.

[0162] In addition, as shown in FIG. 2, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, with respect to data symbol 502) in phase change section 209B, the influence of a sharp drop in electric field strength on the frequency axis in multipath can be reduced, and thus there is a possibility of obtaining the effect that the reception quality of the data of data symbol 402 and data symbol 502 is improved.

[0163] Thus, the difference in "the symbol targets for which phase changes are applied in phase change section 205B" and "the symbol targets for which phase changes are applied in phase change section 209B" is a characteristic point.

[0164] As described above, by performing phase change by phase change section 205B in FIG. 2, the effect that the reception quality of the data of data symbol 402 and data symbol 502, particularly in a LOS environment, at the receiving device can be improved can be obtained, and by performing phase change by phase change section 209B in FIG. 2, for example, the reception quality of the control information symbols included in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" at the receiving device can be improved, and the effect that the demodulation and decoding operations of data symbol 402 and data symbol 502 can be simplified can be obtained.

[0165] By performing phase change by the phase change unit 205B in FIG. 2, it is possible to obtain the effect that the reception quality of data in the receiving device is improved for the data symbol 402 and the data symbol 502, particularly in the LOS environment. Further, by performing phase change on the data symbol 402 and the data symbol 502 by the phase change unit 209B in FIG. 2, the reception quality of the data symbol 402 and the data symbol 502 will be improved.

[0166] Note that in FIG. 2, the phase change unit 209B is provided at the subsequent stage of the insertion unit 207B, and an example of a configuration for performing phase change on the baseband signal 208B is illustrated. However, the configuration for obtaining both the effect of phase change by the above-described phase change unit 205B and the effect of phase change by the phase change unit 209B is not limited to the configuration shown in FIG. 2. For example, the phase change unit 209B may be removed from the configuration of FIG. 2, the baseband signal 208B output from the insertion unit 207B may be used as the signal 106_B after signal processing, and a phase change unit 209A that performs the same operation as the phase change unit 209B may be added at the subsequent stage of the insertion unit 207A, and the phase-changed signal 210A obtained by the phase change unit 209A performing phase change on the baseband signal 208A may be used as the signal 106_A after signal processing. Even with such a configuration, similar to the case of FIG. 2 described above, by performing phase change by the phase change unit 205B, it is possible to obtain the effect that the reception quality of data in the receiving device is improved for the data symbol 402 and the data symbol 502, particularly in the LOS environment. Further, by performing phase change on the data symbol 402 and the data symbol 502 by the phase change unit 209A, it is possible to obtain the effect that the reception quality of the data symbol 402 and the data symbol 502 is improved.

[0167] Furthermore, it is also possible to obtain the effect that the reception quality of the control information symbol included in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" in the receiving device is improved.

[0168] (Supplementary Note 1) In Embodiment 1 and the like, it was described that the operation of the "phase change unit B" may be CDD (CSD) described in Non-Patent Document 2 and Non-Patent Document 3. Supplementary explanation will be given on this point.

[0169] FIG. 15 shows a configuration when CDD (CSD) is used. 1501 is a modulation signal when no cyclic delay is applied, and is represented as X[n].

[0170] The cyclic delay unit (circular delay unit) 1502_1 takes the modulation signal 1501 as an input, performs cyclic delay (circular delay) processing, and outputs the signal 1503_1 after the cyclic delay processing. If the signal 1503_1 after the cyclic delay processing is denoted as X1[n], then X1[n] is given by the following equation. That is, X1[n] is given by the following equation.

[0171]

Equation

[0172] Note that δ1 is the cyclic delay amount (δ1 is a real number), X[n] is composed of N symbols (N is an integer of 2 or more), and thus, n is an integer from 0 to N - 1. ···

[0173] The cyclic delay unit (circular delay unit) 1502_M takes the modulation signal 1501 as an input, performs cyclic delay (circular delay) processing, and outputs the signal 1503_M after the cyclic delay processing. If the signal 1503_M after the cyclic delay processing is denoted as XM[n], then XM[n] is given by the following equation.

[0174]

Equation

[0175] Note that δM is the cyclic delay amount (δM is a real number), X[n] is composed of N symbols (N is an integer of 2 or more), and thus, n is an integer from 0 to N - 1.

[0176] Therefore, the cyclic delay unit (circular delay unit) 1502_i (where i is an integer from 1 to M (M is an integer of 1 or more)) takes the modulation signal 1501 as an input, performs the cyclic delay (circular delay) process, and outputs the signal 1503_i after the cyclic delay process. If the signal 1503_i after the cyclic delay process is denoted as Xi[n], Xi[n] is given by the following equation.

[0177]

Equation

[0178] Note that δi is the cyclic delay amount (δi is a real number), X[n] is composed of N symbols (N is an integer of 2 or more), and thus, n is an integer from 0 to N - 1.

[0179] And the signal 1503_i after the cyclic delay process will be transmitted from antenna i. (Therefore, the signals 1503_1, ···, the signals 1503_M after the cyclic delay process will be transmitted from different antennas respectively.)

[0180] By doing so, the diversity effect due to the cyclic delay can be obtained (in particular, the adverse effect of the delayed wave can be reduced), and in the receiving device, the effect of improving the reception quality of the data can be obtained.

[0181] For example, the phase change unit 209B in FIG. 2 may be replaced with the cyclic delay unit shown in FIG. 15, and the operation of the phase change unit 209B may be the same as the operation of the cyclic delay unit.

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

[0183] [Number]

[0184] Note that Y[n] is composed of N symbols (N is an integer of 2 or more), and therefore, n is an integer from 0 to N-1.

[0185] Next, the relationship between the cyclic delay amount and the phase change will be described.

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

[0187] In FIG. 16, 1601 is a symbol. Assuming that the horizontal axis represents frequency (carrier number) and the carriers are arranged in ascending order from low frequency to high frequency. Therefore, if the carrier with the lowest frequency is "carrier 1", then the subsequent carriers are "carrier 2", "carrier 3", "carrier 4", and so on.

[0188] And, for example, in the phase change unit 209B of FIG. 2, assume that a cyclic delay amount τ is given. Then, the phase change value Ω[i] at "carrier i" is expressed as follows.

[0189] [Number]

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

[0191] Assuming that the baseband signal of "carrier i" at time t before phase change (before the cyclic delay process) is v'[i][t], the signal v[i][t] of "carrier i" at time t after the phase change can be expressed as v[i][t] = Ω[i] × v'[i][t].

[0192] (Supplementary Note 2) Naturally, it is also possible to implement by combining multiple embodiments and other contents described in this specification.

[0193] Also, each embodiment and other contents 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 exemplified, it is possible to implement with a similar configuration even when applying other "modulation method, error correction coding method (error correction code used, code length, coding rate, etc.), control information, etc.".

[0194] Regarding the modulation method, it is possible to implement the embodiments and other contents described in this specification even when using a modulation method other than the modulation methods described in this specification. 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, 256QAM, 1024QAM, 4096QAM, etc.) may be applied, and in each modulation method, it may be uniform mapping or non-uniform mapping.

[0195] Also, the arrangement methods of 2, 4, 8, 16, 64, 128, 256, 1024, etc. signal points in the I-Q plane (modulation methods having 2, 4, 8, 16, 64, 128, 256, 1024, etc. signal points) are not limited to the signal point arrangement methods of the modulation methods shown in this specification. Therefore, the function of outputting the in-phase component and the quadrature component based on a plurality of bits becomes the function of the mapping unit, and then, performing precoding and phase change becomes one effective function of the present invention.

[0196] And, in this specification, when "∀" and "∃" exist, "∀" represents the universal quantifier, and "∃" represents the existential quantifier.

[0197] Also, in this specification, when there is a complex plane, for example, the unit of phase such as the argument is "radian".

[0198] Using the complex plane, it can be expressed in polar form as the polar coordinate representation of a complex number. When a point (a, b) on the complex plane is corresponded to a complex number z = a + jb (both a and b are real numbers, and j is the imaginary unit), if this point is expressed as [r, θ] in polar coordinates, then a = r × cosθ, b = r × sinθ

Number

[0199] In this specification, the receiving device of the terminal and the antenna may be separate. For example, the receiving device is provided with an interface for inputting, through a cable, a signal received by the antenna or a signal obtained by subjecting the signal received by the antenna to frequency conversion, and the receiving device performs subsequent processing.

[0200] Also, the data / information obtained by the receiving device is then converted into video or sound, and is displayed on a display (monitor) or sound is output from a speaker. Further, the data / information obtained by the receiving device may be subjected to signal processing related to video or sound (signal processing is not necessarily required), and may be output from an RCA terminal (video terminal, audio terminal), USB (Universal Serial Bus), HDMI (registered trademark) (High-Definition Multimedia Interface), digital terminal, etc. provided in the receiving device.

[0201] In this specification, it is conceivable that communication and broadcasting devices such as a broadcasting station, a base station, an access point, a terminal, and a mobile phone are equipped with a transmitting device. At this time, it is conceivable that communication devices such as a television, a radio, a terminal, a personal computer, a mobile phone, an access point, and a base station are equipped with a receiving device. Also, the transmitting device and the receiving device in the present invention are devices having a communication function, and it is also conceivable that the device is in a form that can be connected by resolving some interface to a device for executing applications such as a television, a radio, a personal computer, and a mobile phone.

[0202] Also, in this embodiment, symbols other than data symbols, for example, pilot symbols (preamble, unique word, postamble, reference symbol, etc.), symbols for control information, etc. may be arranged in the frame in any manner. Here, they are named pilot symbols and symbols for control information, but any naming method may be used, and the function itself is important.

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

[0204] Also, the symbol for control information is a symbol for transmitting information (for example, modulation method, error correction coding method, coding rate of error correction coding method, setting information at the upper layer, etc.) that needs to be transmitted to the communication partner to realize communication other than data (such as that of an application, etc.).

[0205] Note that the present invention is not limited to each embodiment and can be implemented with various modifications. For example, in each embodiment, the case of performing as a communication device is described, but it is not limited thereto, and it is also possible to perform this communication method as software.

[0206] Also, in the above, the precoding switching method in the method of transmitting two modulation signals from two antennas has been described, but it is not limited thereto. For four signals after mapping, precoding is performed to generate four modulation signals and transmit them from four antennas. That is, in the method of performing precoding on N signals after mapping, generating N modulation signals, and transmitting them from N antennas, the precoding weight (matrix) can be changed in the same way, and the precoding switching method can be implemented in the same way.

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

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

[0209] The transmitting antenna of the transmitting device and the receiving antenna of the receiving device, each of the antennas described in the drawings may be composed of a plurality of antennas.

[0210] The transmitting device needs to notify the receiving device of the transmission method (MIMO, SISO, space-time block code, interleaving method), modulation method, and error correction coding method. This may be omitted depending on the embodiment. which will be present in the frame transmitted by the transmitting device. The receiving device will obtain this and change its operation accordingly.

[0211] For example, a program for executing the above communication method may be stored in a ROM (Read Only Memory) in advance, and the program may be operated by a CPU (Central Processor Unit).

[0212] Alternatively, a program for executing the above communication method may be stored in a computer-readable storage medium, the program stored in the storage medium may be recorded in the RAM (Random Access Memory) of the computer, and the computer may be operated according to the program.

[0213] Furthermore, each configuration such as those described in the above embodiments may typically be implemented as an LSI (Large Scale Integration), which is an integrated circuit. These may be implemented as individual chips, or may be integrated into a single chip so as to include all or some of the configurations of each embodiment. Here, we have described it as an LSI, but depending on the degree of integration, it may also be referred to as an IC (Integrated Circuit), a system LSI, a super LSI, or an ultra LSI. Also, the method of integrating circuits is not limited to LSI, and it may also be implemented using an application-specific circuit or a general-purpose processor. After manufacturing the LSI, an FPGA (Field Programmable Gate Array) that can be programmed, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used.

[0214] Furthermore, if a technology for integrating circuits that replaces LSI appears due to the progress of semiconductor technology or another derived technology, naturally, the integration of functional blocks may be performed using that technology. The application of biotechnology, etc. may be possible as a possibility.

[0215] The present invention can be widely applied to a wireless system that transmits different modulation signals from a plurality of antennas. Also, in a wired communication system having a plurality of transmission locations (for example, a PLC (Power Line Communication) system, an optical communication system, a DSL (Digital Subscriber Line) system), the present invention can also be applied to the case of performing MIMO transmission.

[0216] (Embodiment 2) In this embodiment, a method of implementation having a configuration different from that of FIG. 2 in Embodiment 1 will be described.

[0217] FIG. 1 is an example of the configuration of a transmission device such as a base station, an access point, or a broadcasting station in this embodiment. Details have been described in Embodiment 1, so the description will be omitted.

[0218] The signal processing unit 106 takes as inputs the signals 105_1 and 105_2 after mapping, the signal group 110, and the control signal 100, performs signal processing based on the control signal 100, and outputs the signals 106_A and 106_B after signal processing. At this time, the signal 106_A after signal processing is represented as u1(i), and the signal 106_B after signal processing is represented as u2(i) (where i is the symbol number, for example, i is an integer greater than or equal to 0). Note that the details of the signal processing will be described with reference to FIG. 18.

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

[0220] The weighted synthesis unit (precoding unit) 203 will perform the operation of Equation (1).

[0221] Then, the phase change unit 205B takes the weighted synthesized signal 204B and the control signal 200 as inputs, and based on the control signal 200, performs a phase change on the weighted synthesized signal 204B and outputs the signal 206B after the phase change. Let the signal 206B after the phase change be represented by 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 change unit 205B will be described. In the phase change unit 205B, for example, a phase change of y(i) is performed on z2’(i). Therefore, it can be expressed as z2(i)=y(i)×z2’(i). (i is the symbol number (i is an integer of 0 or more))

[0223] For example, the value of the phase change is set as in Equation (2). (N is an integer of 2 or more, and N is the period of the phase change.) (When N is set to an odd number of 3 or more, the reception quality of the data may be improved.) However, Equation (2) is merely an example and is not limited thereto. Therefore, the phase change value y(i)=e j×δ(i) shall be expressed as

[0224] At this time, z1(i) and z2(i) can be expressed by Equation (3). Note that δ(i) is a real number. And z1(i) and z2(i) will be transmitted from the transmission device at the same time and the same frequency (the same frequency band). In Equation (3), the value of the phase change is not limited to Equation (2), and for example, a method of changing the phase periodically and regularly can be considered.

[0225] Then, as described in Embodiment 1, as the (precoding) matrix in Equation (1) and Equation (3), Equation (5) to Equation (36) etc. can be considered. (However, the precoding matrix is not limited to these. (The same applies to Embodiment 1.))

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

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

[0228] The phase change unit 209A receives as inputs the baseband signal 208A and the control signal 200, performs a phase change on the baseband signal 208A based on the control signal 200, and outputs a signal 210A after phase change. Let the baseband signal 208A be a function of the symbol number i (i is an integer greater than or equal to 0), denoted as x’(i). Then, the signal 210A (x(i)) after phase change can be expressed as x(i) = e j×ε(i) ×x’(i). (j is the imaginary unit)

[0229] Note that, as described in Embodiment 1 and the like, the operation of the phase change unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209A is that it performs a phase change on the symbols existing in the frequency axis direction (performs a phase change on data symbols, pilot symbols, control information symbols, etc.).

[0230] FIG. 3 is an example of the configuration of the radio units 107_A and 107_B in FIG. 1, and since it has been described in detail in Embodiment 1, the description is omitted.

[0231] FIG. 4 shows the frame configuration of the transmission signal 108_A in FIG. 1. Since it has been described in detail in Embodiment 1, the description will be omitted.

[0232] FIG. 5 shows the frame configuration of the transmission signal 108_B in FIG. 1. Since it has been described in detail in Embodiment 1, the description will be omitted.

[0233] When there are symbols at carrier A and time $B in FIG. 4 and there are symbols at carrier A and time $B in FIG. 5, the symbols at carrier A and time $B in FIG. 4 and the symbols at carrier A and time $B in FIG. 5 will be transmitted at the same time and the same frequency. Note that the frame configuration is not limited to FIGS. 4 and 5. FIGS. 4 and 5 are merely examples of the frame configuration.

[0234] The other symbols in FIGS. 4 and 5 correspond to the "preamble signal 252 and control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 4 transmits control information, it transmits the same data (the same control information).

[0235] Although it is assumed that the receiving device receives the frames of FIGS. 4 and 5 simultaneously, the receiving device can obtain the data transmitted by the transmitting device even if it receives only the frame of FIG. 4 or only the frame of FIG. 5.

[0236] FIG. 6 shows an example of the configuration of a part related to control information generation for generating the control information signal 253 in FIG. 2. Since it has been described in detail in Embodiment 1, the description will be omitted.

[0237] FIG. 7 shows an example of the configuration of the antenna unit #A (109_A) and the antenna unit #B (109_B) in FIG. 1 (an example in which the antenna unit #A (109_A) and the antenna unit #B (109_B) are composed of a plurality of antennas). Since it has been described in detail in Embodiment 1, the description will be omitted.

[0238] FIG. 8 shows an example of the configuration of a receiving device that receives the modulation signal when the transmitting device of FIG. 1 transmits a transmission signal having the frame configurations of FIGS. 4 and 5, for example. Since detailed description was given in Embodiment 1, the description is omitted.

[0239] FIG. 10 shows an example of the configuration of the antenna unit #X (801X) and the antenna unit #Y (801Y) of FIG. 8. (This is an example in which the antenna unit #X (801X) and the antenna unit #Y (801Y) are each composed of a plurality of antennas.) Since detailed description was given in Embodiment 1 for FIG. 10, the description is omitted.

[0240] Next, as shown in FIG. 18, the signal processing unit 106 of the transmitting device inserts a phase change unit 205B and a phase change unit 209A as shown in FIG. 1. The features and the effects at that time will be described.

[0241] As described with reference to FIGS. 4 and 5, for the post-mapping signal s1(i) (201A) obtained by mapping using the first sequence (where i is a symbol number and i is an integer of 0 or more) and the post-mapping signal s2(i) (201B) obtained by mapping using the second sequence, precoding (weighted synthesis) is performed, and phase change is performed on one of the obtained weighted synthesis signals 204A and 204B by the phase change unit 205B. Then, the weighted synthesis signal 204A and the phase-changed signal 206B are to be transmitted at the same frequency and the same time. Therefore, in FIGS. 4 and 5, phase change is to be performed on the data symbol 502 of FIG. 5. (In the case of FIG. 18, since the phase change unit 205 performs the operation on the weighted synthesis signal 204B, phase change is performed on the data symbol 502 of FIG. 5. When performing phase change on the weighted synthesis signal 204A, phase change is to be performed on the data symbol 402 of FIG. 4. This point will be described later.)

[0242] For example, FIG. 11 extracts carriers 1 to 5 and times $4 to $6 from the frame of FIG. 5. Similar to FIG. 5, 501 is a pilot symbol, 502 is a data symbol, and 503 is another symbol.

[0243] As described above, in the symbols shown in FIG. 11, for the data symbols at (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 a phase change.

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

[0245] On the other hand, in the symbols shown in FIG. 11, the other symbols of (Carrier 1, Time $4$), the other symbols of (Carrier 2, Time $4$), the other symbols of (Carrier 3, Time $4$), the other symbols of (Carrier 4, Time $4$), the other symbols of (Carrier 5, Time $4$), and the pilot symbol of (Carrier 3, Time $6$) are not the objects of phase change by the phase change unit 205B.

[0246] This point is a characteristic point of the phase change unit 205B. Note that 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 $6$) which are the objects of phase change in FIG. 11 and "the same carrier, the same time", as shown in FIG. 4, data carriers are arranged. That is, in FIG. 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, the data symbols performing MIMO transmission (transmitting a plurality of streams) are the objects of phase change by the phase change unit 205B.)

[0247] As an example of the phase change applied by the phase change unit 205B to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (2). (However, the phase change method applied to the data symbol is not limited to this.)

[0248] By doing so, in an environment where the direct wave is dominant, particularly in an LOS environment, it is possible to obtain the effect that the reception quality of data in a receiving device that is performing MIMO transmission (transmitting a plurality of streams) is improved. This effect will be described.

[0249] 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. 18 is a QPSK signal, and the signal 201B after mapping is also a QPSK signal. That is, two QPSK streams are to be transmitted.) Then, in the signal processing unit 811 of FIG. 8, for example, 16 candidate signal points are 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 are to be transmitted. Therefore, 2 4 = 16 candidate signal points exist) (Note that another 16 candidate signal points can also 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.)

[0250] 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 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".)

[0251] In an environment where the direct wave is dominant, particularly in an LOS environment, The first case: Consider the case where the phase change unit 205B in FIG. 18 does not exist (that is, when the phase change by the phase change unit 205B in FIG. 18 is not performed). Let's think about it.

[0252] In the case of "the first case", since no phase change is performed, it may fall into the state as shown in Fig. 12(A). If it falls into the state of Fig. 12(A), there are portions where signal points are dense (the distance between signal points is short), such as "signal points 1201 and 1202", "signal points 1203, 1204, 1205, 1206", and "signal points 1207, 1208". Therefore, in the receiving device of Fig. 8, the reception quality of data may deteriorate.

[0253] To overcome this problem, in Fig. 18, a phase change unit 205B is inserted. When the phase change unit 205B is inserted, due to symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in Fig. 12(A) and a symbol number with "a long distance between signal points" as shown in Fig. 12(B) will be mixed. For this state, since an error correction code is introduced, a high error correction ability can be obtained, and in the receiving device of Fig. 8, a high data reception quality can be obtained.

[0254] Note that in Fig. 18, for "pilot symbols, preambles", etc., which are used for channel estimation to demodulate (detect) data symbols, no phase change is performed in the phase change unit 205B of Fig. 18. Thereby, in the data symbols, "it can be realized that a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in Fig. 12(A) and a symbol number with 'a long distance between signal points' as shown in Fig. 12(B) are mixed due to symbol number i".

[0255] However, for "pilot symbols, preambles", etc. that are used for channel estimation to demodulate (detect) data symbols, even if phase change is performed in the phase change unit 205B of FIG. 18, "in data symbols, there may be a case where a symbol number with dense signal points (short distance between signal points) as shown in FIG. 12(A) and a symbol number with 'long distance between signal points' as shown in FIG. 12(B) coexist". In this case, some conditions must be added to the pilot symbols and preambles, and phase change must be performed. For example, a rule different from the rule for phase change of data symbols can be set, and a method of "performing phase change on pilot symbols and / or preambles" can be considered. As an example, there is a method of regularly performing phase change with a period N on data symbols and regularly performing phase change with a period M on pilot symbols and / or preambles. (N and M are integers of 2 or more.)

[0256] As described above, the phase change unit 209A takes the baseband signal 208A and the control signal 200 as inputs, performs phase change on the baseband signal 208A based on the control signal 200, and outputs the signal 210A after phase change. Let the baseband signal 208A be a function of the symbol number i (where i is an integer of 0 or more) and be represented as x'(i). Then, the signal 210A (x(i)) after phase change is x(i)=e j×ε(i)It can be expressed as ×x’(i) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209A is that it performs phase change on the symbols existing in the frequency axis direction (performs phase change on 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 FIG. 18, since the phase change unit 209A performs phase change on the baseband signal 208A, it performs phase change on each symbol described in FIG. 4.)

[0257] Therefore, in the frame of FIG. 4, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 18 performs phase change.

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

[0259] FIG. 13 has a frame configuration different from that of FIG. 4 of the transmission signal 108_A in FIG. 1. Since detailed explanations were given in Embodiment 1, the explanations are omitted.

[0260] FIG. 14 has a frame configuration different from that of FIG. 5 of the transmission signal 108_B in FIG. 1. Since detailed explanations were given in Embodiment 1, the explanations are omitted.

[0261] When there is a symbol at carrier A and time $B in FIG. 13, and when there is a symbol at carrier A and time $B in FIG. 14, the symbol at carrier A and time $B in FIG. 13 and the symbol at carrier A and time $B in FIG. 14 will be transmitted at the same time and the same frequency. Note that the frame configurations in FIGS. 13 and 14 are merely examples.

[0262] And the other symbols in FIGS. 13 and 14 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 18". Therefore, when the other symbol 503 in FIG. 14 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 13 is transmitting control information, it will be transmitting the same data (the same control information).

[0263] Although it is assumed that the receiving device will receive the frames of FIGS. 13 and 14 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 13 or only the frame of FIG. 14.

[0264] 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 symbol number i (where i is an integer greater than or equal to 0) and be represented 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) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209A is that it performs phase change on the symbols existing in the frequency axis direction (performs phase change on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if a phase change is performed on a null symbol, the signal before the phase change and the signal after the phase change are the same (the in-phase 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 objects of phase change. (In the case of FIG. 18, since the phase change unit 209A performs a phase change on the baseband signal 208A, a phase change is performed on each symbol described in FIG. 13.)

[0265] Therefore, in the frame of FIG. 13, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described above.

[0266] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described above." "For all symbols from carrier 1 to carrier 36 at time $3 (in this case, all become other symbol 403), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $4 (in this case, all become other symbol 403), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $5 (in this case, they become pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $6 (in this case, they become pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $7 (in this case, they become pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $8 (in this case, they become pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $9 (in this case, they become pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, it becomes pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 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 $11 (in this case, it becomes pilot symbol 401 or data symbol 402), the phase change unit 209A in FIG. 18 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." ···

[0267] Let the phase change value in the phase change unit 209A be represented by Ω(i). The baseband signal 208A is x'(i), and the signal 210A after the phase change is x(i). Therefore, x(i) = Ω(i) × x'(i) holds."

[0268] For example, set the phase change value as in Equation (38). (Q is an integer of 2 or more, and Q is the period of the phase change.) (j is the imaginary unit) However, Equation (38) is merely an example and is not limited to this."

[0269] For example, Ω(i) may be set so that the phase change is performed with a period Q."

[0270] Also, for example, in FIGS. 4 and 13, it is also possible to give the same phase change value to the same carrier and set the phase change value for each carrier. For example, it becomes as follows." · For carrier 1 in FIGS. 4 and 13, regardless of the time, the phase change value is set as in Equation (39). · For carrier 2 in FIGS. 4 and 13, regardless of the time, the phase change value is set as in Equation (40). · For carrier 3 in FIGS. 4 and 13, regardless of the time, the phase change value is set as in Equation (41). ·For the carrier 4 in FIGS. 4 and 13, regardless of time, the phase change value is given by Equation (42). ···

[0271] The above is an operation example of the phase change unit 209A in FIG. 18.

[0272] The effects obtained by the phase change unit 209A in FIG. 18 will be described.

[0273] Assume that the other symbols 403 and 503 in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" include control information symbols. As described above, the other symbol 503 in FIG. 5 at the same time and with the same frequency (the same carrier) as the other symbol 403 transmits the same data (the same control information) when transmitting control information.

[0274] By the way, consider the following cases.

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

[0276] When transmitted as in "Case 2", since the number of antennas transmitting the control information symbol is 1, the spatial diversity gain is smaller compared to the case of "transmitting the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)". Therefore, in the case of "Case 2", even when received by the receiving device in FIG. 8, the reception quality of the data will deteriorate. Thus, in terms of improving the reception quality of the data, it is better to "transmit the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)".

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

[0278] When transmitting as in "Case 3", since the modulated signal transmitted from the antenna unit #A 109_A and the modulated signal transmitted from the antenna unit #B 109_B are the same (or have a specific phase shift), depending on the radio wave propagation environment, the receiving device in FIG. 8 may have a very poor received signal, and both modulated signals may be affected by the same multipath. As a result, there is a problem that the reception quality of data deteriorates in the receiving device of FIG. 8.

[0279] To mitigate this problem, in FIG. 18, a phase change unit 209A is provided. As a result, the phase is changed in the time or frequency direction, so the possibility of a poor received signal can be reduced in the receiving device of FIG. 8. In addition, since it is highly likely that there is a difference between the influence of multipath received by the modulated signal transmitted from the antenna unit #A 109_A and the influence of multipath received by the modulated signal transmitted from the antenna unit #B 109_B, there is a high possibility of obtaining a diversity gain, and as a result, the reception quality of data will be improved in the receiving device of FIG. 8.

[0280] For the above reasons, in FIG. 18, a phase change unit 209A is provided and a phase change is performed.

[0281] In addition to the control information symbol, the other symbols 403 and the other symbols 503 include, for example, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) for demodulating and decoding the control information symbol. Also, the "frames of FIGS. 4 and 5" or the "frames of FIGS. 13 and 14" include pilot symbols 401 and 501, and by using these, it becomes possible to demodulate and decode the control information symbol with higher accuracy.

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

[0283] 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 fluctuations) included in other symbols 403 and other symbols 503" are being phase-changed by the phase change unit 209A as described above.

[0284] In such a situation, if this process is not reflected in data symbol 402 and data symbol 502 (in the case of the above description, for data symbol 402), when the receiving device demodulates and decodes data symbol 402 and data symbol 502, it is necessary to perform demodulation and decoding that reflects the process of the phase change performed by the phase change unit 209A, and that process is likely to become complicated. (Since the "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503" are being phase-changed by the phase change unit 209A)

[0285] However, as shown in FIG. 18, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, to data symbol 402) in phase change section 209A, at the receiving device, there is an advantage that data symbol 402 and data symbol 502 can be demodulated and decoded (simply) using the channel estimation signal (propagation path fluctuation estimation signal) estimated using "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations)" included in other symbol 403 and other symbol 503.

[0286] In addition, as shown in FIG. 18, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, to data symbol 402) in phase change section 209A, it is possible to reduce the influence of a sharp drop in electric field strength on the frequency axis in multipath, and thus there is a possibility of obtaining an effect that the reception quality of the data of data symbol 402 and data symbol 502 is improved.

[0287] Thus, the difference in "the symbol target for which phase change is applied in phase change section 205B" and "the symbol target for which phase change is applied in phase change section 209A" is a characteristic point.

[0288] As described above, by performing phase change with phase change section 205B in FIG. 18, it is possible to obtain an effect that the reception quality of the data of data symbol 402 and data symbol 502, particularly in a LOS environment, at the receiving device is improved, and by performing phase change with phase change section 209A in FIG. 18, for example, for the control information symbols included in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14", the reception quality at the receiving device is improved and an effect that the demodulation and decoding operations of data symbol 402 and data symbol 502 are simplified can be obtained.

[0289] By performing phase change with the phase change unit 205B in FIG. 18, it is possible to obtain the effect that the reception quality of data in the receiving device is improved for the data symbols 402 and 502, particularly in the LOS environment. Furthermore, by performing phase change on the data symbols 402 and 502 with the phase change unit 209A in FIG. 18, the reception quality of the data symbols 402 and 502 will be improved.

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

[0291] (Embodiment 3) In this embodiment, an implementation method with a configuration different from that of FIG. 2 in Embodiment 1 will be described.

[0292] FIG. 1 is an example of the configuration of a transmission device such as a base station, an access point, or a broadcasting station in this embodiment. Since the details have been described in Embodiment 1, the description will be omitted.

[0293] The signal processing unit 106 takes as inputs the signals 105_1 and 105_2 after mapping, the signal group 110, and the control signal 100, performs signal processing based on the control signal 100, and outputs the signals 106_A and 106_B after signal processing. At this time, the signal 106_A after signal processing is represented as u1(i), and the signal 106_B after signal processing is represented as u2(i) (where i is the symbol number, for example, i is an integer of 0 or more). Note that the details of the signal processing will be described with reference to FIG. 19.

[0294] FIG. 19 shows an example of the configuration of the signal processing unit 106 in FIG. 1. The weighted synthesis unit (precoding unit) 203 takes as inputs the signal 201A after mapping (corresponding to the signal 105_1 after mapping in FIG. 1), the signal 201B after mapping (corresponding to the signal 105_2 after mapping in FIG. 1), and the control signal 200 (corresponding to the control signal 100 in FIG. 1), performs weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, let the signal 201A after mapping be s1(t), the signal 201B after mapping be s2(t), the weighted signal 204A be z1(t), and the weighted signal 204B be z2’(t). Note that, as an example, t is time. (s1(t), s2(t), z1(t), z2’(t) are defined as complex numbers. (Therefore, they may be real numbers))

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

[0296] The weighted synthesis unit (precoding unit) 203 performs the operation of Equation (1).

[0297] Then, the phase change unit 205B takes as inputs the signal 204B after weighted synthesis and the control signal 200, and based on the control signal 200, performs a phase change on the signal 204B after weighted synthesis, and outputs the signal 206B after phase change. Let the signal 206B after phase change be represented by z2(t), and z2(t) is defined as a complex number. (It may be a real number.)

[0298] The specific operation of the phase change unit 205B will be described. In the phase change unit 205B, for example, it is assumed that a phase change of y(i) is performed on z2’(i). Therefore, it can be expressed as z2(i) = y(i) × z2’(i). (i is the symbol number (i is an integer greater than or equal to 0))

[0299] For example, the value of the phase change is set as in Equation (2). (N is an integer of 2 or more, and N is the period of the phase change.) (If N is set to an odd number of 3 or more, the reception quality of the data may be improved.) However, Equation (2) is merely an example and is not limited thereto. Therefore, let the phase change value y(i) = e j×δ(i) be expressed as follows.

[0300] At this time, z1(i) and z2(i) can be expressed by Equation (3). Note that δ(i) is a real number. And z1(i) and z2(i) will be transmitted from the transmission device at the same time and the same frequency (the same frequency band). In Equation (3), the value of the phase change is not limited to Equation (2), and for example, a method of changing the phase periodically and regularly can be considered.

[0301] And, as described in Embodiment 1, as the (precoding) matrix in Equation (1) and Equation (3), Equation (5) to Equation (36) etc. can be considered. (However, the precoding matrix is not limited to these. (The same applies to Embodiment 1.))

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

[0303] Similarly, the insertion unit 207B takes as inputs the signal 206B after phase change, the pilot symbol signal (pb(t)) (251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200, and outputs a baseband signal 208B based on the frame configuration according to the information on the frame configuration included in the control signal 200.

[0304] 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 can be expressed as x(i)=e j×ε(i) ×x'(i). (j is the imaginary unit)

[0305] Note that, as described in Embodiment 1 and the like, the operation of the phase change unit 209A may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209A is that it performs a phase change on the symbols existing in the frequency axis direction (performs a phase change on data symbols, pilot symbols, control information symbols, etc.).

[0306] The phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B be a function of the symbol number i (where i is an integer greater than or equal to 0), denoted as y'(i). Then, the signal 210B(y(i)) after the phase change can be expressed as y(i)=e j×τ(i) ×y'(i). (j is the imaginary unit)

[0307] Note that, as described in Embodiment 1 and the like, the operation of the phase change unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209B is that it performs a phase change on the symbols existing in the frequency axis direction (performs a phase change on data symbols, pilot symbols, control information symbols, etc.).

[0308] The characteristic point here is that the phase change method by ε(i) is different from the phase change method by τ(i). Or, it is the point that the value of the cyclic delay amount of CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) set in the phase change 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 change unit 209B.

[0309] FIG. 3 is an example of the configuration of the radio units 107_A and 107_B in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0310] FIG. 4 is the frame configuration of the transmission signal 108_A in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0311] FIG. 5 is the frame configuration of the transmission signal 108_B in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0312] When there is a symbol at carrier A and time $B in FIG. 4 and there is a symbol at carrier A and time $B in FIG. 5, the symbol at carrier A and time $B in FIG. 4 and the symbol at carrier A and time $B in FIG. 5 will be transmitted at the same time and the same frequency. Note that the frame configuration is not limited to FIGS. 4 and 5, and FIGS. 4 and 5 are merely examples of the frame configuration.

[0313] And the other symbols in FIGS. 4 and 5 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 4 is transmitting control information, it will be transmitting the same data (the same control information).

[0314] Note that although it is assumed that the receiving device will receive the frame of FIG. 4 and the frame of FIG. 5 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device even if it receives only the frame of FIG. 4 or only the frame of FIG. 5.

[0315] FIG. 6 shows an example of the configuration of a part related to control information generation for generating the control information signal 253 of FIG. 2. Since it was described in detail in Embodiment 1, the description will be omitted.

[0316] FIG. 7 shows an example of the configuration of the antenna unit #A (109_A) and the antenna unit #B (109_B) of FIG. 1 (this is an example in which the antenna unit #A (109_A) and the antenna unit #B (109_B) are composed of a plurality of antennas). Since it was described in detail in Embodiment 1, the description will be omitted.

[0317] FIG. 8 shows an example of the configuration of a receiving device that receives the modulation signal when the transmitting device of FIG. 1 transmits a transmission signal having the frame configurations of FIGS. 4 and 5. Since it was described in detail in Embodiment 1, the description will be omitted.

[0318] FIG. 10 shows an example of the configuration of the antenna unit #X (801X) and the antenna unit #Y (801Y) of FIG. 8. (This is an example in which the antenna unit #X (801X) and the antenna unit #Y (801Y) are composed of a plurality of antennas.) Regarding FIG. 10, since it was described in detail in Embodiment 1, the description will be omitted.

[0319] Next, as shown in FIG. 19, the signal processing unit 106 of the transmitting device inserts a phase change unit 205B and phase change units 209A and 209B as shown in FIG. 1. The features and the effects at that time will be described.

[0320] As described with reference to FIGS. 4 and 5, for the post-mapping signal s1(i) (201A) obtained by mapping using the first series (where i is the symbol number and i is an integer equal to or greater than 0) and the post-mapping signal s2(i) (201B) obtained by mapping using the second series, precoding (weighted synthesis) is performed, and phase change is performed on one of the obtained weighted synthesis signals 204A and 204B by the phase change unit 205B. Then, the weighted synthesis signal 204A and the phase-changed signal 206B are transmitted at the same frequency and at the same time. Therefore, in FIGS. 4 and 5, phase change is performed on the data symbol 502 in FIG. 5. (In the case of FIG. 19, since the phase change unit 205 performs the operation on the weighted synthesis signal 204B, phase change is performed on the data symbol 502 in FIG. 5. When performing phase change on the weighted synthesis signal 204A, phase change is performed on the data symbol 402 in FIG. 4. This point will be described later.)

[0321] For example, FIG. 11 extracts carriers 1 to 5 and times $4 to $6 from the frame of FIG. 5. Similar to FIG. 5, 501 is a pilot symbol, 502 is a data symbol, and 503 is another symbol.

[0322] As described above, in the symbols shown in FIG. 11, the phase change unit 205B performs phase change on the data symbols at (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 symbols shown in FIG. 11, the phase change value of the data symbol at (carrier 1, time $5) is "e" j×δ15(i)is set to "e", and the phase change value of the data symbol at (carrier 2, time $5) is "e" j×δ25(i) is set to "e", and the phase change value of the data symbol at (carrier 3, time $5) is "e" j×δ35(i) is set to "e", and the phase change value of the data symbol at (carrier 4, time $5) is "e" j×δ45(i) is set to "e", and the phase change value of the data symbol at (carrier 5, time $5) is "e" j×δ55(i) is set to "e", and the phase change value of the data symbol at (carrier 1, time $6) is "e" j×δ16(i) is set to "e", and the phase change value of the data symbol at (carrier 2, time $6) is "e" j×δ26(i) is set to "e", and the phase change value of the data symbol at (carrier 4, time $6) is "e" j×δ46(i) is set to "e", and the phase change value of the data symbol at (carrier 5, time $6) is "e" j×δ56(i) is set.

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

[0325] This is a characteristic point of the phase change unit 205B. Note that, as shown in FIG. 4, 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), (carrier 5, time $6) which are the objects of phase change in FIG. 11, and for "the same carrier, the same time", data carriers are arranged. That is, in FIG. 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, the data symbols performing MIMO transmission (transmitting a plurality of streams) are the objects of phase change of the phase change unit 205B.)

[0326] Note that, as an example of the phase change applied by the phase change unit 205B to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (2). (However, the phase change method applied to the data symbol is not limited to this.)

[0327] By doing so, in an environment where the direct wave is dominant, particularly in an LOS environment, it is possible to obtain the effect that the reception quality of data in the receiving device of the data symbol performing MIMO transmission (transmitting a plurality of streams) is improved. This effect will be described.

[0328] 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. 19 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 also 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.)

[0329] 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. (Among the 16 candidate signal points, one is the signal point transmitted by the transmitting device. Therefore, it is called "16 candidate signal points".)

[0330] 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. 19 does not exist (that is, when the phase change by the phase change unit 205B in FIG. 19 is not performed). Let's think about it.

[0331] 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.

[0332] To overcome this problem, in FIG. 19, a phase change unit 205B is inserted. When the phase change unit 205B is inserted, due to symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number with "the distance between signal points is long" as shown in FIG. 12(B) are mixed. In response to this state, since an error correction code is introduced, a high error correction capability can be obtained, and in the receiving apparatus of FIG. 8, a high data reception quality can be obtained.

[0333] Note that in FIG. 19, for "pilot symbols, preambles", etc., which are for channel estimation to demodulate (detect) data symbols, no phase change is performed in the phase change unit 205B of FIG. 19. Thereby, in the data symbol, "due to symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number with "the distance between signal points is long" as shown in FIG. 12(B) are mixed" can be realized.

[0334] However, for "pilot symbols, preambles", etc. that are used for channel estimation to demodulate (detect) data symbols, even if phase change is performed in the phase change unit 205B of FIG. 19, there may be a case where "in data symbols, a symbol number where there is a part where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number where 'the distance between signal points is long' as shown in FIG. 12(B) coexist" can be realized. In this case, some conditions must be added to the pilot symbols and preambles, and phase change must be performed. For example, a method of "performing phase change on pilot symbols and / or preambles" can be considered by setting a rule different from the rule of phase change for data symbols. As an example, there is a method of regularly performing phase change with a period N on data symbols and regularly performing phase change with a period M on pilot symbols and / or preambles. (N and M are integers of 2 or more.)

[0335] As described above, the phase change unit 209A takes the baseband signal 208A and the control signal 200 as inputs, performs phase change on the baseband signal 208A based on the control signal 200, and outputs the signal 210A after phase change. Let the baseband signal 208A be a function of the symbol number i (where i is an integer of 0 or more) and be represented as x'(i). Then, the signal 210A (x(i)) after phase change is x(i) = e j×ε(i)It can be expressed as ×x’(i) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209A, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on 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 FIG. 19, since the phase change unit 209A performs phase change on the baseband signal 208A, phase change is performed on each symbol described in FIG. 4.)

[0336] Therefore, in the frame of FIG. 4, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 19 performs phase change.

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

[0338] As described above, the phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B be a function of the symbol number i (where i is an integer greater than or equal to 0) and be represented as y'(i). Then, the signal 210B (y(i)) after the phase change is y(i)=e j×τ(i)It can be expressed as ×y’(i) (j is the imaginary unit). As for the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it performs a phase change on the symbols existing in the frequency axis direction (performs a phase change on 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 FIG. 19, since the phase change unit 209B performs a phase change on the baseband signal 208B, a phase change is performed on each symbol described in FIG. 5.)

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

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

[0341] FIG. 13 has a different frame configuration from FIG. 4 of the transmission signal 108_A in FIG. 1. Since it was described in detail in Embodiment 1, the description is omitted.

[0342] FIG. 14 has a different frame configuration from FIG. 5 of the transmission signal 108_B in FIG. 1. Since it was described in detail in Embodiment 1, the description is omitted.

[0343] When there is a symbol at carrier A and time $B in FIG. 13, and when there is a symbol at carrier A and time $B in FIG. 14, the symbol at carrier A and time $B in FIG. 13 and the symbol at carrier A and time $B in FIG. 14 will be transmitted at the same time and the same frequency. Note that the frame configurations in FIGS. 13 and 14 are merely examples.

[0344] And the other symbols in FIGS. 13 and 14 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 19". Therefore, when the other symbol 503 in FIG. 14 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 13 is transmitting control information, it will be transmitting the same data (the same control information).

[0345] Although it is assumed that the receiving device will receive the frames of FIGS. 13 and 14 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 13 or only the frame of FIG. 14.

[0346] 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 symbol number i (where i is an integer greater than or equal to 0) and be represented 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) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209A, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if a phase change is performed on a null symbol, the signal before phase change and the signal after phase change are the same (the in-phase 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 objects of phase change. (In the case of FIG. 19, since the phase change unit 209A performs a phase change on the baseband signal 208A, a phase change is performed on each symbol described in FIG. 13.)

[0347] Therefore, in the frame of FIG. 13, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 19 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before.

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

[0349] Let the phase change value in the phase change unit 209A be represented as Ω(i). The baseband signal 208A is x’(i), and the signal 210A after the phase change is x(i). Therefore, x(i) = Ω(i) × x’(i) holds."

[0350] For example, set the value of the phase change by Equation (38). (Q is an integer of 2 or more, and Q is the period of the phase change.) (j is the imaginary unit) However, Equation (38) is merely an example and is not limited to this."

[0351] For example, Ω(i) may be set so that the phase change is performed with a period Q."

[0352] Also, for example, in FIGS. 4 and 13, it may be assumed that the same phase change value is given to the same carrier and the phase change value is set for each carrier. For example, it may be as follows." · For carrier 1 in FIGS. 4 and 13, regardless of the time, let the phase change value be Equation (39). · For carrier 2 in FIGS. 4 and 13, regardless of the time, let the phase change value be Equation (40). · For carrier 3 in FIGS. 4 and 13, regardless of the time, let the phase change value be Equation (41). ·For the carrier 4 in FIGS. 4 and 13, regardless of time, the phase change value is given by Equation (42). ···

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

[0354] The phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B be a function of the symbol number i (where i is an integer greater than or equal to 0), denoted as y'(i). Then, the signal 210B (y(i)) after the phase change can be expressed as y(i) = e j×τ(i) ×y'(i). (j is the imaginary unit) And as the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it performs a phase change on the symbols existing in the frequency axis direction (performs a phase change on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by the symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if a phase change is performed on a null symbol, the signal before and after the phase change is the same (the in-phase 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 objects of phase change. (In the case of FIG. 19, since the phase change unit 209B performs a phase change on the baseband signal 208B, a phase change is performed on each symbol described in FIG. 14.)

[0355] 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 symbols 503), the phase change unit 209B in FIG. 19 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as previously described.

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

[0357] Let the phase change value in the phase change unit 209B be represented as Ω(i). 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."

[0358] For example, set the value of the phase change as the following formula. (R is an integer of 2 or more, and R is the period of the phase change. It is preferable that the values of Q and R in formula (38) are different values.)

[0359]

Number

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

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

[0362] Also, for example, in FIGS. 5 and 14, it may be assumed that the same phase change value is given to the same carrier and the phase change value is set for each carrier. For example, it may be as follows. · For carrier 1 in FIGS. 5 and 14, the phase change value is Equation (39) regardless of time. · For carrier 2 in FIGS. 5 and 14, the phase change value is Equation (40) regardless of time. · For carrier 3 in FIGS. 5 and 14, the phase change value is Equation (41) regardless of time. · For carrier 4 in FIGS. 5 and 14, the phase change value is 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 the phase change unit 209A and the phase change unit 209B are different.)

[0364] The above is an operation example of the phase change unit 209B in FIG. 19.

[0365] The effects obtained by the phase change units 209A and 209B in FIG. 19 will be described.

[0366] Assume that the other symbols 403 and 503 of "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" contain control information symbols. As described previously, when the other symbol 503 of FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 transmits control information, it transmits the same data (the same control information).

[0367] Now, consider the following cases.

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

[0369] When transmitted as in "Case 2", since the number of antennas transmitting the control information symbol is 1, the spatial diversity gain is smaller compared to the case of "transmitting the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)". Therefore, in the case of "Case 2", even when received by the receiving device in FIG. 8, the reception quality of the data will deteriorate. Thus, in terms of improving the reception quality of the data, it is better to "transmit the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)".

[0370] Case 3: The control information symbol is transmitted using both the antenna unit #A (109_A) and the antenna unit #B (109_B) in FIG. 1. However, no phase change is performed by the phase change units 209A and 209B in FIG. 19.

[0371] When transmitted as in "Case 3", since the modulated signals transmitted from antenna unit #A109_A and the modulated signals transmitted from antenna unit #B109_B are the same (or have a specific phase shift), depending on the radio wave propagation environment, the receiving device in FIG. 8 may have a very poor received signal, and both modulated signals may be affected by the same multipath. As a result, there is a problem that the reception quality of data deteriorates in the receiving device of FIG. 8.

[0372] To mitigate this problem, in FIG. 19, phase change units 209A and 209B are provided. As a result, since the phase is changed in the time or frequency direction, the possibility of obtaining a poor received signal can be reduced in the receiving device of FIG. 8. In addition, since it is highly likely that there is a difference between the influence of multipath received by the modulated signal transmitted from antenna unit #A109_A and the influence of multipath received by the modulated signal transmitted from antenna unit #B109_B, there is a high possibility of obtaining a diversity gain. As a result, the reception quality of data will be improved in the receiving device of FIG. 8.

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

[0374] In addition to control information symbols, other symbols 403 and other symbols 503 include, for example, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) for demodulating and decoding control information symbols. Also, the "frames of FIGS. 4 and 5" or the "frames of FIGS. 13 and 14" include pilot symbols 401 and 501. By using these, it becomes possible to demodulate and decode control information symbols with higher accuracy.

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

[0376] At this time, as described above, the "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503" are subjected to phase change by phase change units 209A and 209B.

[0377] In such a situation, if this processing is not reflected in data symbols 402 and data symbols 502, when the receiving device demodulates and decodes data symbols 402 and data symbols 502, it is necessary to perform demodulation and decoding that reflects the processing for the phase change performed by phase change units 209A and 209B, and the processing is likely to become complicated. (Since the "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503" are subjected to phase change by phase change units 209A and 209B)

[0378] However, as shown in FIG. 19, when phase changes are applied to data symbols 402 and data symbols 502 in phase change units 209A and 209B, in the receiving device, "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503" are used. There is an advantage that the data symbols 402 and the data symbols 502 can be (simply) demodulated and decoded using the estimated channel estimation signal (propagation path fluctuation estimation signal).

[0379] In addition, as shown in FIG. 19, when phase changes are applied to data symbols 402 and data symbols 502 in phase change units 209A and 209B, it is possible to reduce the influence of a sharp drop in field strength on the frequency axis in multipath, and thereby, there is a possibility of obtaining an effect that the reception quality of the data of the data symbols 402 and the data symbols 502 is improved.

[0380] Thus, the difference in "the symbol targets for which the phase change unit 205B performs phase change" and "the symbol targets for which the phase change units 209A and 209B perform phase change" is a characteristic point.

[0381] As described above, by performing phase change by the phase change unit 205B in FIG. 19, it is possible to obtain an effect that the reception quality of the data of the data symbols 402 and the data symbols 502, particularly in a LOS environment, in the receiving device is improved. Also, by performing phase change by the phase change units 209A and 209B in FIG. 19, for example, the reception quality of the control information symbols included in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" in the receiving device is improved, and an effect that the demodulation and decoding operations of the data symbols 402 and the data symbols 502 are simplified can be obtained.

[0382] By performing phase change with the phase change unit 205B in FIG. 19, it is possible to obtain the effect that the reception quality of data in the receiving device is improved for the data symbols 402 and 502, particularly in the LOS environment. Further, by performing phase change on the data symbols 402 and 502 with the phase change units 209A and 209B in FIG. 19, the reception quality of the data symbols 402 and 502 will be improved.

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

[0384] And R in Expression (49) may be an integer of -2 or less. In this case, the period of the phase change is the absolute value of R.

[0385] Also, considering the content described in Supplementary Note 1, it is preferable to set different values for the round-trip delay amount set in the phase change unit 209A and the round-trip delay amount set in the phase change unit 209B.

[0386] (Embodiment 4) In this embodiment, an implementation method with a configuration different from that of FIG. 2 in Embodiment 1 will be described.

[0387] FIG. 1 is an example of the configuration of a transmission device such as a base station, an access point, or a broadcasting station in this embodiment. Since the details have been described in Embodiment 1, the description will be omitted.

[0388] The signal processing unit 106 takes as inputs the signals 105_1 and 105_2 after mapping, the signal group 110, and the control signal 100, performs signal processing based on the control signal 100, and outputs the signals 106_A and 106_B after signal processing. At this time, the signal 106_A after signal processing is represented as u1(i), and the signal 106_B after signal processing is represented as u2(i) (where i is the symbol number, for example, i is an integer greater than or equal to 0). Note that the details of the signal processing will be described with reference to FIG. 20.

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

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

[0391] The weighted synthesis unit (precoding unit) 203 performs the following operations.

[0392]

Equation

[0393] Then, the phase change unit 205A takes the weighted synthesized signal 204A and the control signal 200 as inputs, and based on the control signal 200, performs a phase change on the weighted synthesized signal 204A and outputs the phase-changed signal 206A. Let the phase-changed signal 206A be represented by z1(t), and z1(t) is defined as a complex number. (It may also be a real number.)

[0394] The specific operation of the phase change unit 205A will be described. In the phase change unit 205A, for example, a phase change of w(i) is performed on z1’(i). Therefore, it can be expressed as z1(i) = w(i) × z1’(i). (i is the symbol number (i is an integer greater than or equal to 0))

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

[0396]

Equation

[0397] Then, the phase change unit 205B takes the weighted synthesized signal 204B and the control signal 200 as inputs, and based on the control signal 200, performs a phase change on the weighted synthesized signal 204B and outputs the phase-changed signal 206B. Let the phase-changed signal 206B be represented by 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 change unit 205B will be described. In the phase change unit 205B, for example, a phase change of y(i) is performed on z2’(i). Therefore, it can be expressed as z2(i) = y(i) × z2’(i). (i is the symbol number (i is an integer greater than or equal to 0))

[0399] For example, the value of phase change is set as in Equation (2). (N is an integer of 2 or more, and N is the period of phase change. N ≠ M) (If N is set to an odd number of 3 or more, the reception quality of data may be improved.) However, Equation (2) is merely an example and is not limited thereto. Therefore, the phase change value y(i) = e j×δ(i) shall be represented as follows.

[0400] At this time, z1(i) and z2(i) can be represented by the following equations.

[0401]

Equation

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

[0403] And, as described in Embodiment 1, as the (precoding) matrix in Equation (50) and Equation (52), Equation (5) to Equation (36) etc. can be considered. (However, the precoding matrix is not limited to these. (The same applies to Embodiment 1.))

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

[0405] Similarly, the insertion unit 207B takes as inputs the signal 206B after phase change, the pilot symbol signal (pb(t)) (251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200, and outputs a baseband signal 208B based on the frame configuration according to the information on the frame configuration included in the control signal 200.

[0406] The phase change unit 209B takes as inputs the baseband signal 208B and the control signal 200, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs a signal 210B after phase change. Let the baseband signal 208B be a function of symbol number i (where i is an integer equal to or greater than 0) and be represented as x’(i). Then, the signal 210B (x(i)) after phase change can be represented as x(i) = e j×ε(i) ×x’(i). (j is the imaginary unit)

[0407] Note that, as described in Embodiment 1 and the like, the operation of the phase change unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209B is that it performs a phase change on the symbols existing in the frequency axis direction (performs a phase change on data symbols, pilot symbols, control information symbols, etc.).

[0408] FIG. 3 is an example of the configurations of the radio units 107_A and 107_B in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0409] FIG. 4 is the frame configuration of the transmission signal 108_A in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0410] FIG. 5 is the frame configuration of the transmission signal 108_B in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0411] When there is a symbol at carrier A and time $B in FIG. 4, and when there is a symbol at carrier A and time $B in FIG. 5, the symbols at carrier A and time $B in FIG. 4 and the symbols at carrier A and time $B in FIG. 5 will be transmitted at the same time and the same frequency. Note that the frame configuration is not limited to FIGS. 4 and 5. FIGS. 4 and 5 are merely examples of the frame configuration.

[0412] And the other symbols in FIGS. 4 and 5 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 4 transmits control information, it will transmit the same data (the same control information).

[0413] Although it is assumed that the receiving device will receive the frames of FIGS. 4 and 5 at the same time, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 4 or only the frame of FIG. 5.

[0414] FIG. 6 shows an example of the configuration of a part related to control information generation for generating the control information signal 253 in FIG. 2. Since it was described in detail in Embodiment 1, the description is omitted.

[0415] FIG. 7 shows an example of the configuration of the antenna unit #A (109_A) and the antenna unit #B (109_B) in FIG. 1 (this is an example in which the antenna unit #A (109_A) and the antenna unit #B (109_B) are composed of a plurality of antennas). Since it was described in detail in Embodiment 1, the description is omitted.

[0416] FIG. 8 shows an example of the configuration of a receiving device that receives the modulation signal when the transmitting device in FIG. 1 transmits a transmission signal having the frame configurations of FIGS. 4 and 5. Since it was described in detail in Embodiment 1, the description is omitted.

[0417] FIG. 10 shows an example of the configuration of the antenna unit #X (801X) and the antenna unit #Y (801Y) in FIG. 8. (This is an example in which the antenna unit #X (801X) and the antenna unit #Y (801Y) are composed of a plurality of antennas.) Since FIG. 10 has been described in detail in Embodiment 1, the description thereof will be omitted.

[0418] Next, as shown in FIG. 1, the signal processing unit 106 of the transmission device inserts a phase change unit 205A, 205B and a phase change unit 209A as shown in FIG. 20. The features and the effects at that time will be described.

[0419] As described with reference to FIGS. 4 and 5, for the post-mapping signal s1(i) (201A) obtained by mapping using the first sequence (where i is the symbol number and i is an integer greater than or equal to 0) and the post-mapping signal s2(i) (201B) obtained by mapping using the second sequence, precoding (weighted synthesis) is performed, and phase changes are performed on the obtained weighted synthesis signals 204A and 204B by the phase change units 205A and 205B. Then, the post-phase change signal 206A and the post-phase change signal 206B are to be transmitted at the same frequency and at the same time. Therefore, in FIGS. 4 and 5, phase changes are to be performed on the data symbol 402 in FIG. 4 and the data symbol 502 in FIG. 5.

[0420] For example, FIG. 11 shows the extraction of carriers 1 to 5 and times $4 to $6 from the frame in FIG. 4. Similar to FIG. 4, 401 is a pilot symbol, 402 is a data symbol, and 403 is another symbol.

[0421] 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 205A will perform a phase change.

[0422] 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×λ15(i) ", the phase change value of the data symbol of (Carrier 2, Time $5) be "e j×λ25(i) ", the phase change value of the data symbol of (Carrier 3, Time $5) be "e j×λ35(i) ", the phase change value of the data symbol of (Carrier 4, Time $5) be "e j×λ45(i) ", the phase change value of the data symbol of (Carrier 5, Time $5) be "e j×λ55(i) ", the phase change value of the data symbol of (Carrier 1, Time $6) be "e j×λ16(i) ", the phase change value of the data symbol of (Carrier 2, Time $6) be "e j×λ26(i) ", the phase change value of the data symbol of (Carrier 4, Time $6) be "e j×λ46(i) ", and the phase change value of the data symbol of (Carrier 5, Time $6) be "e j×λ56(i) ".

[0423] 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 205A.

[0424] This is a characteristic point of the phase change unit 205A. Note that, as shown in FIG. 4, 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), (carrier 5, time $6) which are the objects of phase change in FIG. 11, and for those with "the same carrier, the same time", data carriers are arranged. That is, in FIG. 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, the data symbols for which MIMO transmission is performed (multiple streams are transmitted) are the objects of phase change in the phase change unit 205A.)

[0425] Note that, as an example of the phase change applied by the phase change unit 205A to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (50). (However, the phase change method applied to the data symbol is not limited to this.)

[0426] For example, FIG. 11 is obtained by extracting carriers 1 to 5 and times $4 to $6 from the frame of FIG. 5. Similar to FIG. 5, 501 is a pilot symbol, 502 is a data symbol, and 503 is another symbol.

[0427] As described above, in the symbol shown in FIG. 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 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) ".

[0429] On the other hand, in the symbol 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.

[0430] This is a characteristic point of the phase change unit 205B. Note that, as shown in FIG. 4, 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), which are the objects of phase change in FIG. 11, and "the same carrier, the same time" have data carriers arranged. That is, in FIG. 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 a plurality of streams) are the objects of phase change of the phase change unit 205B.)

[0431] Note that, as an example of the phase change applied by the phase change unit 205B to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as in Equation (2). (However, the phase change method applied to the data symbol is not limited to this.)

[0432] By doing so, in an environment where the direct wave is dominant, particularly in an LOS environment, it is possible to obtain an effect that the reception quality of data in the receiving device of data symbols performing MIMO transmission (transmitting a plurality of streams) is improved. This effect will be described.

[0433] 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. 18 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 also be obtained using the channel estimation signals 808_1 and 808_2. However, 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.)

[0434] 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. (Among the 16 candidate signal points, one is the signal point transmitted by the transmitting device. Therefore, it is called "16 candidate signal points".)

[0435] In an environment where the direct wave is dominant, especially in a LOS environment, Case 1: Consider the case where the phase change units 205A and 205B in FIG. 20 do not exist (that is, when the phase change by the phase change units 205A and 205B in FIG. 20 is not performed). Let's think about it.

[0436] 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.

[0437] To overcome this problem, in FIG. 20, phase change units 205A and 205B are inserted. When the phase change units 205A and 205B are inserted, depending on symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number with "a long distance between signal points" as shown in FIG. 12(B) are mixed. In response to this state, since an error correction code is introduced, a high error correction ability can be obtained, and in the receiving apparatus of FIG. 8, a high data reception quality can be obtained.

[0438] Note that in FIG. 20, for "pilot symbols, preambles", etc. for channel estimation for demodulating (detecting) data symbols, such as pilot symbols and preambles, no phase change is performed in the phase change units 205A and 205B of FIG. 20. Thereby, in the data symbols, "depending on symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number with 'a long distance between signal points' as shown in FIG. 12(B) are mixed" can be realized.

[0439] 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. 20, there may be a case where "in data symbols, a symbol number where there is a part where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number where 'the distance between signal points is long' as shown in FIG. 12(B) coexist" 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 of 2 or more.)

[0440] As described above, the phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B be a function of the symbol number i (where i is an integer of 0 or more) and be represented as x'(i). Then, the signal 210B (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). As for the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on 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 FIG. 20, since the phase change unit 209B performs phase change on the baseband signal 208B, it will perform phase change on each symbol described in FIG. 5.)

[0441] Therefore, in the frame of FIG. 5, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 503), the phase change unit 209B in FIG. 20 performs phase change.

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

[0443] FIG. 13 has a frame configuration different from that of FIG. 4 of the transmission signal 108_A in FIG. 1. In Embodiment 1, detailed description has been given, so the description is omitted.

[0444] FIG. 14 has a frame configuration different from that of FIG. 5 of the transmission signal 108_B in FIG. 1. In Embodiment 1, detailed description has been given, so the description is omitted.

[0445] When there is a symbol at carrier A and time $B in FIG. 13, and when there is a symbol at carrier A and time $B in FIG. 14, the symbol at carrier A and time $B in FIG. 13 and the symbol at carrier A and time $B in FIG. 14 will be transmitted at the same time and the same frequency. Note that the frame configurations in FIGS. 13 and 14 are merely examples.

[0446] And the other symbols in FIGS. 13 and 14 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 20". Therefore, when the other symbol 503 in FIG. 14 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 13 transmits control information, it will transmit the same data (the same control information).

[0447] Although it is assumed that the receiving device will receive the frames of FIGS. 13 and 14 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 13 or only the frame of FIG. 14.

[0448] The phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B be a function of the symbol symbol number i (where i is an integer greater than or equal to 0), denoted as x'(i). Then, the signal 210B (x(i)) after the phase change is x(i)=e j×ε(i)It can be expressed as ×x’(i) (j is the imaginary unit). As for the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if a phase change is performed on a null symbol, the signal before the phase change and the signal after the phase change are the same (the in-phase 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 objects of phase change. (In the case of FIG. 20, since the phase change unit 209B performs a phase change on the baseband signal 208B, a phase change is performed on each symbol described in FIG. 14.)

[0449] 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 symbols 503), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before.

[0450] Similarly, "For all symbols from carrier 1 to carrier 36 at time $2 (in this case, all become other symbols 503), the phase change unit 209B in FIG. 20 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. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "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. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $5$ (in this case, they become pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $6$ (in this case, they become pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $7$ (in this case, they become pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $8$ (in this case, they become pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $9$ (in this case, they become pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described previously." "For all symbols from carrier 1 to carrier 36 at time $10 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 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 $11 (in this case, it becomes pilot symbol 501 or data symbol 502), the phase change unit 209B in FIG. 20 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before." ···

[0451] Let the phase change value in the phase change unit 209B be represented by Ω(i). The baseband signal 208B is x’(i), and the signal 210B after the phase change is x(i). Therefore, x(i) = Ω(i) × x’(i) holds."

[0452] For example, set the value of the phase change by Equation (38). (Q is an integer of 2 or more, and Q is the period of the phase change.) (j is the imaginary unit) However, Equation (38) is only an example and is not limited to this."

[0453] For example, Ω(i) may be set so that the phase change is performed with a period Q."

[0454] Also, for example, in FIGS. 5 and 14, it may be assumed that the same phase change value is given to the same carrier and the phase change value is set for each carrier. For example, it may be as follows." · For carrier 1 in FIGS. 5 and 14, regardless of time, let the phase change value be Equation (39). · For carrier 2 in FIGS. 5 and 14, regardless of time, let the phase change value be Equation (40). · For carrier 3 in FIGS. 5 and 14, regardless of time, let the phase change value be Equation (41). · For the carrier 4 in FIGS. 5 and 14, regardless of time, the phase change value is given by Equation (42). ···

[0455] The above is an example of the operation of the phase change unit 209B in FIG. 20.

[0456] The effects obtained by the phase change unit 209B in FIG. 20 will be described.

[0457] Assume that the other symbols 403 and 503 in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" include control information symbols. As described above, the other symbol 503 in FIG. 5 at the same time and with the same frequency (the same carrier) as the other symbol 403 transmits the same data (the same control information) when transmitting control information.

[0458] By the way, consider the following cases.

[0459] Case 2: The control information symbol is transmitted using either one of the antenna units #A (109_A) or #B (109_B) in FIG. 1.

[0460] When transmitted as in "Case 2", since the number of antennas transmitting the control information symbol is 1, the spatial diversity gain is smaller compared to the case of "transmitting the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)". Therefore, when receiving at the receiving device in FIG. 8 in the case of "Case 2", the reception quality of the data will deteriorate. Thus, in terms of improving the reception quality of the data, it is better to "transmit the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)".

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

[0462] When transmitted as in "Case 3", since the modulated signal transmitted from the antenna unit #A 109_A and the modulated signal transmitted from the antenna unit #B 109_B are the same (or have a specific phase shift), depending on the radio wave propagation environment, the receiving device in FIG. 8 may have a very poor received signal, and both modulated signals may be affected by the same multipath. As a result, there is a problem that the reception quality of data deteriorates in the receiving device of FIG. 8.

[0463] To mitigate this problem, in FIG. 20, a phase change unit 209B is provided. As a result, since the phase is changed in the time or frequency direction, the possibility of a poor received signal can be reduced in the receiving device of FIG. 8. In addition, since it is highly likely that there is a difference between the influence of multipath received by the modulated signal transmitted from the antenna unit #A 109_A and the influence of multipath received by the modulated signal transmitted from the antenna unit #B 109_B, there is a high possibility of obtaining a diversity gain, and as a result, the reception quality of data will be improved in the receiving device of FIG. 8.

[0464] For the above reasons, in FIG. 20, a phase change unit 209B is provided and a phase change is performed.

[0465] In addition to the control information symbol, the other symbols 403 and the other symbols 503 include, for example, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) for demodulating and decoding the control information symbol. Also, the "frames of FIGS. 4 and 5" or the "frames of FIGS. 13 and 14" include pilot symbols 401 and 501, and by using these, it becomes possible to demodulate and decode the control information symbol with higher accuracy.

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

[0467] 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 fluctuations) included in other symbols 403 and other symbols 503" are phase-changed by the phase change unit 209B as described above.

[0468] In such a situation, if this process is not reflected in data symbols 402 and data symbols 502 (in the case of the above description, with respect to data symbols 502), when the receiving device demodulates and decodes data symbols 402 and data symbols 502, it is necessary to perform demodulation and decoding that reflects the process for the phase change performed by the phase change unit 209B, and that process is likely to become complicated. (Since the "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503" are phase-changed by the phase change unit 209B)

[0469] However, as shown in FIG. 20, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, to data symbol 502) in phase change unit 209B, at the receiving device, "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations)" included in other symbol 403 and other symbol 503 are used for estimation. There is an advantage that data symbol 402 and data symbol 502 can be demodulated and decoded (simply) using the channel estimation signal (propagation path fluctuation estimation signal).

[0470] In addition, as shown in FIG. 20, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, to data symbol 502) in phase change unit 209B, the influence of a sharp drop in electric field strength on the frequency axis in multipath can be reduced. As a result, it is possible to obtain an effect that the reception quality of the data of data symbol 402 and data symbol 502 is improved.

[0471] Thus, the difference between "the symbols to which the phase changes of phase change units 205A and 205B are applied" and "the symbols to which the phase change of phase change unit 209B is applied" is a characteristic point.

[0472] As described above, by performing phase changes with phase change units 205A and 205B in FIG. 20, it is possible to obtain an effect that the reception quality of the data of data symbol 402 and data symbol 502, particularly in a LOS environment, is improved at the receiving device. Also, by performing phase changes with phase change unit 209B in FIG. 20, for example, the reception quality of the control information symbols included in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" is improved at the receiving device, and an effect that the demodulation and decoding operations of data symbol 402 and data symbol 502 are simplified can be obtained.

[0473] By performing phase change by the phase change units 205A and 205B in FIG. 20, it is possible to obtain the effect that the reception quality of data at the receiving device is improved for the data symbols 402 and 502, particularly in the LOS environment. Further, by performing phase change on the data symbols 402 and 502 by the phase change unit 209B in FIG. 20, the reception quality of the data symbols 402 and 502 will be improved.

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

[0475] (Embodiment 5) In this embodiment, an implementation method with a configuration different from that of FIG. 2 in Embodiment 1 will be described.

[0476] FIG. 1 is an example of the configuration of a transmission device such as a base station, an access point, or a broadcasting station in this embodiment. Since the details have been described in Embodiment 1, the description will be omitted.

[0477] The signal processing unit 106 takes as inputs the signals 105_1 and 105_2 after mapping, the signal group 110, and the control signal 100, performs signal processing based on the control signal 100, and outputs the signals 106_A and 106_B after signal processing. At this time, the signal 106_A after signal processing is represented as u1(i), and the signal 106_B after signal processing is represented as u2(i) (where i is the symbol number, for example, i is an integer of 0 or more). Note that the details of the signal processing will be described with reference to FIG. 21.

[0478] Figure 21 shows an example of the configuration of the signal processing unit 106 in FIG. 1. The weighted synthesis unit (precoding unit) 203 takes as inputs the signal 201A after mapping (corresponding to the signal 105_1 after mapping in FIG. 1), the signal 201B after mapping (corresponding to the signal 105_2 after mapping in FIG. 1), and the control signal 200 (corresponding to the control signal 100 in FIG. 1), performs weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, let the signal 201A after mapping be s1(t), the signal 201B after mapping be s2(t), the weighted signal 204A be z1’(t), and the weighted signal 204B be z2’(t). Note that, as an example, t is time. (s1(t), s2(t), z1’(t), z2’(t) are defined as complex numbers. (Therefore, they may be real numbers))

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

[0480] The weighted synthesis unit (precoding unit) 203 performs the operation of Equation (49).

[0481] Then, the phase change unit 205A takes as inputs the signal 204A after weighted synthesis and the control signal 200, and based on the control signal 200, performs a phase change on the signal 204A after weighted synthesis, and outputs the signal 206A after phase change. Let the signal 206A after phase change be represented by z1(t), and z1(t) is defined as a complex number. (It may be a real number.)

[0482] The specific operation of the phase change unit 205A will be described. In the phase change unit 205A, for example, a phase change of w(i) is performed on z1’(i). Therefore, it can be expressed as z1(i) = w(i) × z1’(i). (i is the symbol number (i is an integer greater than or equal to 0))

[0483] For example, the value of the phase change is set as in Equation (50).

[0484] (M is an integer of 2 or more, and M is the period of the phase change.) (If M is set to an odd number of 3 or more, the reception quality of the data may be improved.) However, Equation (50) is merely an example and is not limited thereto. Therefore, the phase change value w(i) = e j×λ(i) shall be expressed as.

[0485] Then, the phase change unit 205B takes the weighted synthesized signal 204B and the control signal 200 as inputs, and based on the control signal 200, performs a phase change on the weighted synthesized signal 204B and outputs the phase-changed signal 206B. Note that the phase-changed signal 206B is represented by z2(t), and z2(t) is defined as a complex number. (It may be a real number.)

[0486] The specific operation of the phase change unit 205B will be described. In the phase change unit 205B, for example, a phase change of y(i) is performed on z2’(i). Therefore, it can be expressed as z2(i) = y(i) × z2’(i). (i is the symbol number (i is an integer of 0 or more))

[0487] For example, the value of the phase change is set as in Equation (2). (N is an integer of 2 or more, and N is the period of the phase change. N ≠ M) (If N is set to an odd number of 3 or more, the reception quality of the data may be improved.) However, Equation (2) is merely an example and is not limited thereto. Therefore, the phase change value y(i) = e j×δ(i) shall be expressed as.

[0488] At this time, z1(i) and z2(i) can be expressed by Equation (51).

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

[0490] And as described in Embodiment 1, as the (precoding) matrix in Equations (49) and (51), Equations (5) to (36) and the like can be considered. (However, the precoding matrix is not limited to these. (The same applies to Embodiment 1.))

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

[0492] Similarly, the insertion unit 207B takes as inputs the signal 206B after phase change, the pilot symbol signal (pb(t)) (251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200, and outputs a baseband signal 208B based on the frame configuration according to the information on the frame configuration included in the control signal 200.

[0493] The phase change unit 209B takes as inputs the baseband signal 208B and the control signal 200, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs a signal 210B after phase change. Let the baseband signal 208B be a function of the symbol number i (i is an integer greater than or equal to 0) and be represented as x’(i). Then, the signal 210B (x(i)) after phase change can be represented as x(i)=e j×ε(i) ×x’(i). (j is the imaginary unit)

[0494] Note that, as described in Embodiment 1 and the like, the operation of the phase change unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209B is that phase change is performed on symbols existing in the frequency axis direction (phase change is performed on data symbols, pilot symbols, control information symbols, etc.).

[0495] FIG. 3 is an example of the configuration of the radio units 107_A and 107_B in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0496] FIG. 4 is the frame configuration of the transmission signal 108_A in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0497] FIG. 5 is the frame configuration of the transmission signal 108_B in FIG. 1, and since it was described in detail in Embodiment 1, the description is omitted.

[0498] When there are symbols at carrier A and time $B in FIG. 4 and there are symbols at carrier A and time $B in FIG. 5, the symbol at carrier A and time $B in FIG. 4 and the symbol at carrier A and time $B in FIG. 5 will be transmitted at the same time and the same frequency. Note that the frame configuration is not limited to FIGS. 4 and 5, and FIGS. 4 and 5 are merely examples of the frame configuration.

[0499] And the other symbols in FIGS. 4 and 5 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 4 is transmitting control information, it is transmitting the same data (the same control information).

[0500] Note that although it is assumed that the receiving device will receive the frame in FIG. 4 and the frame in FIG. 5 simultaneously, the receiving device can obtain the data transmitted by the transmitting device even if it receives only the frame in FIG. 4 or only the frame in FIG. 5.

[0501] FIG. 6 shows an example of the configuration of a part related to control information generation for generating the control information signal 253 in FIG. 2. Since it was described in detail in Embodiment 1, the description will be omitted.

[0502] FIG. 7 shows an example of the configuration of the antenna unit #A (109_A) and the antenna unit #B (109_B) in FIG. 1 (this is an example in which the antenna unit #A (109_A) and the antenna unit #B (109_B) are composed of a plurality of antennas). Since it was described in detail in Embodiment 1, the description will be omitted.

[0503] FIG. 8 shows an example of the configuration of a receiving device that receives the modulation signal when the transmitting device in FIG. 1 transmits a transmission signal having the frame configurations in FIGS. 4 and 5. Since it was described in detail in Embodiment 1, the description will be omitted.

[0504] FIG. 10 shows an example of the configuration of the antenna unit #X (801X) and the antenna unit #Y (801Y) in FIG. 8. (This is an example in which the antenna unit #X (801X) and the antenna unit #Y (801Y) are composed of a plurality of antennas.) Regarding FIG. 10, since it was described in detail in Embodiment 1, the description will be omitted.

[0505] Next, as shown in FIG. 21, the signal processing unit 106 of the transmitting device in FIG. 1 inserts the phase change units 205A, 205B and the phase change unit 209B. The features and the effects at that time will be described.

[0506] As described with reference to FIGS. 4 and 5, for the mapped signal s1(i) (201A) obtained by mapping using the first series (where i is the symbol number and i is an integer of 0 or more) and the mapped signal s2(i) (201B) obtained by mapping using the second series, precoding (weighted synthesis) is performed, and phase changes are performed on the obtained weighted synthesis signals 204A and 204B by phase change units 205A and 205B. Then, the phase-changed signal 206A and the phase-changed signal 206B are to be transmitted at the same frequency and at the same time. Therefore, in FIGS. 4 and 5, phase changes are to be performed on the data symbol 402 in FIG. 4 and the data symbol 502 in FIG. 5.

[0507] For example, FIG. 11 extracts carriers 1 to 5 and times $4 to $6 from the frame of FIG. 4. Similar to FIG. 4, 401 is a pilot symbol, 402 is a data symbol, and 403 is another symbol.

[0508] As described above, in the symbols shown in FIG. 11, the phase change unit 205A performs phase changes on the data symbols at (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 symbols shown in FIG. 11, the phase change value of the data symbol at (carrier 1, time $5) is set to "e j×λ15(i) ", the phase change value of the data symbol at (carrier 2, time $5) is set to "e j×λ25(i) ", the phase change value of the data symbol at (carrier 3, time $5) is set to "e j×λ35(i) ", and the phase change value of the data symbol at (carrier 4, time $5) is set to "e j×λ45(i)is set to "e", which is the phase change value of the data symbol at (carrier 5, time $5). j×λ55(i) is set to "e", which is the phase change value of the data symbol at (carrier 1, time $6). j×λ16(i) is set to "e", which is the phase change value of the data symbol at (carrier 2, time $6). j×λ26(i) is set to "e", which is the phase change value of the data symbol at (carrier 4, time $6). j×λ46(i) is set to "e", which is the phase change value of the data symbol at (carrier 5, time $6). j×λ56(i) is set to "e".

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

[0511] This point is a characteristic point of the phase change unit 205A. Note that, as shown in FIG. 4, 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), (carrier 5, time $6) which are the objects of phase change in FIG. 11, and for "the same carrier, the same time", data carriers are arranged. That is, in FIG. 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, the data symbols for which MIMO transmission is performed (multiple streams are transmitted) are the objects of phase change by the phase change unit 205A.)

[0512] Note that, as an example of the phase change applied by the phase change unit 205A to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (50). (However, the phase change method applied to the data symbol is not limited to this.)

[0513] For example, FIG. 11 is obtained by extracting carriers 1 to 5 and times $4 to $6 from the frame of FIG. 5. Similar to FIG. 5, 501 is a pilot symbol, 502 is a data symbol, and 503 is another symbol.

[0514] As described above, in the symbols shown in FIG. 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).

[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) ", 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) ".

[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 characteristic point of the phase change unit 205B. Note that 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), (carrier 5, time $6) which are the objects of phase change in FIG. 11, and for those with "the same carrier, the same time", as shown in FIG. 4, data carriers are arranged. That is, in FIG. 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, the data symbols performing MIMO transmission (transmitting multiple streams) are the objects of phase change of the phase change unit 205B.)

[0518] Note that as an example of the phase change applied by the phase change unit 205B to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (2). (However, the phase change method applied to the data symbol is not limited to this.)

[0519] By doing so, in an environment where the direct wave is dominant, especially in an LOS environment, it is possible to obtain the effect that the reception quality of data in the receiving device of the data symbol performing MIMO transmission (transmitting multiple streams) is improved. This effect will be explained.

[0520] 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. 18 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 also 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.)

[0521] 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. (Among the 16 candidate signal points, one is the signal point transmitted by the transmitting device. Therefore, it is called "16 candidate signal points".)

[0522] In an environment where the direct wave is dominant, especially in an LOS environment, Case 1: When the phase change units 205A and 205B in FIG. 21 do not exist (that is, when the phase change by the phase change units 205A and 205B in FIG. 21 is not performed) is considered.

[0523] 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.

[0524] To overcome this problem, in FIG. 21, phase change units 205A and 205B are inserted. When the phase change units 205A and 205B are inserted, depending on symbol number i, there will be a mixture of symbol numbers with portions where 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). In response to this state, since an error correction code is introduced, a high error correction capability can be obtained, and in the receiver of FIG. 8, a high data reception quality can be obtained.

[0525] Note that in FIG. 21, for "pilot symbols, preambles," etc. for channel estimation for demodulating (detecting) data symbols, no phase change is performed in the phase change units 205A and 205B of FIG. 21. As a result, in the data symbols, "depending on symbol number i, there will be a mixture of symbol numbers with portions where 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.

[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, a symbol number with a dense signal point (a short distance between signal points) as shown in FIG. 12(A) and a symbol number with a long distance between signal points as shown in FIG. 12(B) coexist". In this case, some conditions must be added to the pilot symbols and preambles, and phase changes must be performed. For example, a method of "performing phase changes on pilot symbols and / or preambles" can be considered by setting a rule different from the rule for phase changes on data symbols. 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 of 2 or more.)

[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 of 0 or more) and be represented 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) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209A, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on 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 FIG. 21, since the phase change unit 209A performs phase change on the baseband signal 208A, phase change is performed on each symbol described in FIG. 4.)

[0528] Therefore, in the frame of FIG. 4, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 21 performs phase change.

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

[0530] FIG. 13 has a frame configuration different from that of FIG. 4 of the transmission signal 108_A in FIG. 1. Since a detailed explanation was given in Embodiment 1, the explanation is omitted.

[0531] FIG. 14 has a frame configuration different from that of FIG. 5 of the transmission signal 108_B in FIG. 1. Since a detailed explanation was given in Embodiment 1, the explanation is omitted.

[0532] When there is a symbol at carrier A and time $B in FIG. 13, and when there is a symbol at carrier A and time $B in FIG. 14, the symbol at carrier A and time $B in FIG. 13 and the symbol at carrier A and time $B in FIG. 14 will be transmitted at the same time and the same frequency. Note that the frame configurations in FIGS. 13 and 14 are merely examples.

[0533] And the other symbols in FIGS. 13 and 14 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 21". Therefore, when the other symbol 503 in FIG. 14 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 13 is transmitting control information, it will be transmitting the same data (the same control information).

[0534] Although it is assumed that the receiving device will receive the frames of FIGS. 13 and 14 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 13 or only the frame of FIG. 14.

[0535] 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 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) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209A, it is to perform a phase change on the symbols existing in the frequency axis direction (perform a phase change on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if a phase change is performed on a null symbol, the signal before the phase change and the signal after the phase change are the same (the in-phase 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 objects of phase change. (In the case of FIG. 21, since the phase change unit 209A performs a phase change on the baseband signal 208A, a phase change is performed on each symbol described in FIG. 13.)

[0536] Therefore, in the frame of FIG. 13, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 21 performs a phase change. However, the handling of the phase change of the null symbol 1301 is as described before.

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

[0538] Let the phase change value in the phase change unit 209A be represented as Ω(i). 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."

[0539] For example, set the phase change value according 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 just an example and is not limited to this."

[0540] For example, Ω(i) may be set so that the phase change is performed with a period Q."

[0541] Also, for example, in FIGS. 4 and 13, it is also possible to give the same phase change value to the same carrier and set the phase change value for each carrier. For example, it would be as follows." · For carrier 1 in FIGS. 4 and 13, regardless of the time, set the phase change value according to Equation (39). · For carrier 2 in FIGS. 4 and 13, regardless of the time, set the phase change value according to Equation (40). · For carrier 3 in FIGS. 4 and 13, regardless of the time, set the phase change value according to Equation (41). · For the carrier 4 in FIGS. 4 and 13, regardless of time, the phase change value is given by Equation (42). ···

[0542] The above is the operation example of the phase change unit 209A in FIG. 21.

[0543] The effects obtained by the phase change unit 209A in FIG. 21 will be described.

[0544] Assume that the other symbols 403 and 503 in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" include control information symbols. As described above, when the other symbol 503 in FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 transmits control information, it transmits the same data (the same control information).

[0545] By the way, consider the following cases.

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

[0547] When transmitted as in "Case 2", since the number of antennas transmitting the control information symbol is 1, the spatial diversity gain is smaller compared to the case of "transmitting the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)". Therefore, in the case of "Case 2", even when received by the receiving device in FIG. 8, the reception quality of the data will deteriorate. Therefore, in terms of improving the reception quality of the data, it is better to "transmit the control information symbol using both the antenna unit #A (109_A) and the antenna unit #B (109_B)".

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

[0549] When transmitted as in "Case 3", since the modulated signal transmitted from the antenna unit #A 109_A and the modulated signal transmitted from the antenna unit #B 109_B are the same (or have a specific phase shift), depending on the radio wave propagation environment, the receiving device in FIG. 8 may have a very poor received signal, and both modulated signals may be affected by the same multipath. As a result, there is a problem that the reception quality of data deteriorates in the receiving device of FIG. 8.

[0550] To mitigate this problem, in FIG. 21, a phase change unit 209A is provided. As a result, since the phase is changed in the time or frequency direction, the possibility of a poor received signal can be reduced in the receiving device of FIG. 8. In addition, since it is highly likely that there is a difference between the influence of multipath received by the modulated signal transmitted from the antenna unit #A 109_A and the influence of multipath received by the modulated signal transmitted from the antenna unit #B 109_B, there is a high possibility of obtaining a diversity gain, and as a result, the reception quality of data will be improved in the receiving device of FIG. 8.

[0551] For the above reasons, in FIG. 21, a phase change unit 209A is provided and a phase change is performed.

[0552] In addition to the control information symbol, the other symbols 403 and the other symbols 503 include, for example, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) for demodulating and decoding the control information symbol. Also, the "frames of FIGS. 4 and 5" or the "frames of FIGS. 13 and 14" include pilot symbols 401 and 501, and by using these, it becomes possible to demodulate and decode the control information symbol with higher accuracy.

[0553] For the "frames of FIGS. 4 and 5" or the "frames of FIGS. 13 and 14", multiple streams are transmitted using the same frequency (band) and the same time by data symbols 402 and data symbols 502 (MIMO transmission is performed). To demodulate these data symbols, symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503 are used.

[0554] 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 fluctuations) included in other symbols 403 and other symbols 503" are subject to phase change by the phase change unit 209A as described above.

[0555] In such a situation, if this process is not reflected in data symbol 402 and data symbol 502 (in the case of the above description, for data symbol 402), when the receiving device demodulates and decodes data symbol 402 and data symbol 502, it is necessary to perform demodulation and decoding that reflects the process for the phase change performed by the phase change unit 209A, and that process is likely to be complicated. (Since the "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path fluctuations) included in other symbols 403 and other symbols 503" are subject to phase change by the phase change unit 209A)

[0556] However, as shown in FIG. 21, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, to data symbol 402) in phase change unit 209A, at the receiving device, there is an advantage that data symbols 402 and 502 can be demodulated and decoded (simply) using the channel estimation signal (propagation path variation estimation signal) estimated using "symbols for signal detection, symbols for frequency synchronization and time synchronization, and symbols for channel estimation (symbols for estimating propagation path variation)" included in other symbol 403 and other symbol 503.

[0557] In addition, as shown in FIG. 21, when phase changes are applied to data symbol 402 and data symbol 502 (in the case of the above description, to data symbol 402) in phase change unit 209A, it is possible to reduce the influence of a sharp drop in electric field strength on the frequency axis in multipath, and thus there is a possibility of obtaining the effect that the reception quality of the data of data symbol 402 and data symbol 502 is improved.

[0558] Thus, the difference in "the symbols to which the phase changes of phase change units 205A and 205B are applied" and "the symbols to which the phase change of phase change unit 209A is applied" is a characteristic point.

[0559] As described above, by performing phase changes by phase change units 205A and 205B in FIG. 21, it is possible to obtain the effect that the reception quality of the data of data symbol 402 and data symbol 502, particularly in a LOS environment, at the receiving device is improved. Also, by performing phase changes by phase change unit 209A in FIG. 21, for example, the reception quality of the control information symbols included in "the frames of FIGS. 4 and 5" or "the frames of FIGS. 13 and 14" at the receiving device is improved, and the effect that the demodulation and decoding operations of data symbol 402 and data symbol 502 are simplified can be obtained.

[0560] By performing phase change by the phase change units 205A and 205B in FIG. 21, the reception quality of data at the receiving device can be improved for the data symbols 402 and 502, particularly in a LOS environment. Further, by performing phase change on the data symbols 402 and 502 by the phase change unit 209A in FIG. 21, the reception quality of the data symbols 402 and 502 will be improved.

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

[0562] (Embodiment 6) In this embodiment, an implementation method with a configuration different from that of FIG. 2 in Embodiment 1 will be described.

[0563] FIG. 1 is an example of the configuration of a transmission device such as a base station, an access point, or a broadcasting station in this embodiment. Since the details have been described in Embodiment 1, the description will be omitted.

[0564] The signal processing unit 106 receives the signals 105_1 and 105_2 after mapping, the signal group 110, and the control signal 100, performs signal processing based on the control signal 100, and outputs the signals 106_A and 106_B after signal processing. At this time, the signal 106_A after signal processing is represented as u1(i), and the signal 106_B after signal processing is represented as u2(i) (i is a symbol number, for example, i is an integer of 0 or more). Note that the details of the signal processing will be described with reference to FIG. 22.

[0565] FIG. 22 shows an example of the configuration of the signal processing unit 106 in FIG. 1. The weighted synthesis unit (precoding unit) 203 takes as inputs the signal 201A after mapping (corresponding to the signal 105_1 after mapping in FIG. 1), the signal 201B after mapping (corresponding to the signal 105_2 after mapping in FIG. 1), and the control signal 200 (corresponding to the control signal 100 in FIG. 1), performs weighted synthesis (precoding) based on the control signal 200, and outputs the weighted signal 204A and the weighted signal 204B. At this time, let the signal 201A after mapping be s1(t), the signal 201B after mapping be s2(t), the weighted signal 204A be z1’(t), and the weighted signal 204B be z2’(t). Note that, as an example, t is time. (s1(t), s2(t), z1’(t), z2’(t) are defined as complex numbers. (Therefore, they may be real numbers))

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

[0567] The weighted synthesis unit (precoding unit) 203 performs the operation of equation (49).

[0568] Then, the phase change unit 205A takes as inputs the signal 204A after weighted synthesis and the control signal 200, and based on the control signal 200, performs a phase change on the signal 204A after weighted synthesis, and outputs the signal 206A after phase change. Let the signal 206A after phase change be represented by z1(t), and z1(t) is defined as a complex number. (It may be a real number.)

[0569] The specific operation of the phase change unit 205A will be described. In the phase change unit 205A, for example, it is assumed that a phase change of w(i) is performed on z1’(i). Therefore, it can be expressed as z1(i)=w(i)×z1’(i). (i is the symbol number (i is an integer of 0 or more))

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

[0571] (M is an integer of 2 or more, and M is the period of the phase change.) (If M is set to an odd number of 3 or more, the reception quality of the data may be improved.) However, Equation (50) is merely an example and is not limited thereto. Therefore, the phase change value w(i)=e j×λ(i) shall be expressed as

[0572] Then, the phase change unit 205B takes the weighted combined signal 204B and the control signal 200 as inputs, and based on the control signal 200, performs a phase change on the weighted combined signal 204B and outputs the phase-changed signal 206B. Let the phase-changed signal 206B be represented by z2(t), and z2(t) is defined as a complex number. (It may be a real number.)

[0573] The specific operation of the phase change unit 205B will be described. In the phase change unit 205B, for example, a phase change of y(i) is performed on z2’(i). Therefore, it can be expressed as z2(i)=y(i)×z2’(i). (i is the symbol number (i is an integer of 0 or more))

[0574] For example, set the value of the phase change as in Equation (2). (N is an integer of 2 or more, and N is the period of the phase change. N≠M) (If N is set to an odd number of 3 or more, the reception quality of the data may be improved.) However, Equation (2) is merely an example and is not limited thereto. Therefore, the phase change value y(i)=e j×δ(i) shall be expressed as

[0575] At this time, z1(i) and z2(i) can be expressed by Equation (51).

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

[0577] As described in Embodiment 1, as the (precoding) matrix in Equations (49) and (51), Equations (5) to (36) etc. can be considered. (However, the precoding matrix is not limited to these. (The same applies to Embodiment 1.))

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

[0579] Similarly, the insertion unit 207B takes as inputs the signal 206B after phase change, the pilot symbol signal (pb(t)) (251B), the preamble signal 252, the control information symbol signal 253, and the control signal 200, and outputs a baseband signal 208B based on the frame configuration according to the information on the frame configuration included in the control signal 200.

[0580] The phase change unit 209B takes as inputs the baseband signal 208B and the control signal 200, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after phase change. Let the baseband signal 208B be a function of the symbol number i (i is an integer greater than or equal to 0), denoted as x’(i). Then, the signal 210B (x(i)) after phase change can be expressed as x(i)=e j×ε(i) ×x’(i). (j is the imaginary unit)

[0581] Note that, as described in Embodiment 1 and the like, the operation of the phase change unit 209B may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And the feature of the phase change unit 209B is that phase change is performed on symbols existing in the frequency axis direction (phase change is performed on data symbols, pilot symbols, control information symbols, etc.).

[0582] FIG. 3 is an example of the configuration of the radio units 107_A and 107_B in FIG. 1, and since it has been described in detail in Embodiment 1, the description is omitted.

[0583] FIG. 4 is the frame configuration of the transmission signal 108_A in FIG. 1, and since it has been described in detail in Embodiment 1, the description is omitted.

[0584] FIG. 5 is the frame configuration of the transmission signal 108_B in FIG. 1, and since it has been described in detail in Embodiment 1, the description is omitted.

[0585] When there are symbols at carrier A and time $B in FIG. 4 and there are symbols at carrier A and time $B in FIG. 5, the symbols at carrier A and time $B in FIG. 4 and the symbols at carrier A and time $B in FIG. 5 will be transmitted at the same time and the same frequency. Note that the frame configuration is not limited to FIGS. 4 and 5, and FIGS. 4 and 5 are merely examples of the frame configuration.

[0586] And the other symbols in FIGS. 4 and 5 are symbols corresponding to "the preamble signal 252 and the control information symbol signal 253 in FIG. 2". Therefore, when the other symbol 503 in FIG. 5 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 4 is transmitting control information, it is transmitting the same data (the same control information).

[0587] Note that although it is assumed that the receiving device will receive the frame of FIG. 4 and the frame of FIG. 5 simultaneously, the receiving device can obtain the data transmitted by the transmitting device even if it receives only the frame of FIG. 4 or only the frame of FIG. 5.

[0588] FIG. 6 shows an example of the configuration of a part related to control information generation for generating the control information signal 253 of FIG. 2. Since it was described in detail in Embodiment 1, the description is omitted.

[0589] FIG. 7 shows an example of the configuration of the antenna unit #A (109_A) and the antenna unit #B (109_B) of FIG. 1 (This is an example in which the antenna unit #A (109_A) and the antenna unit #B (109_B) are composed of a plurality of antennas.). Since it was described in detail in Embodiment 1, the description is omitted.

[0590] FIG. 8 shows an example of the configuration of a receiving device that receives the modulation signal when the transmitting device of FIG. 1 transmits a transmission signal having the frame configurations of FIGS. 4 and 5. Since it was described in detail in Embodiment 1, the description is omitted.

[0591] FIG. 10 shows an example of the configuration of the antenna unit #X (801X) and the antenna unit #Y (801Y) of FIG. 8. (This is an example in which the antenna unit #X (801X) and the antenna unit #Y (801Y) are composed of a plurality of antennas.) Regarding FIG. 10, since it was described in detail in Embodiment 1, the description is omitted.

[0592] Next, as shown in FIG. 22, the signal processing unit 106 of the transmitting device inserts the phase change units 205A, 205B and the phase change unit 209B as shown in FIG. 1. The features and the effects at that time will be described.

[0593] As described with reference to FIGS. 4 and 5, for the post-mapping signal s1(i) (201A) obtained by mapping using the first series (where i is the symbol number and i is an integer equal to or greater than 0) and the post-mapping signal s2(i) (201B) obtained by mapping using the second series, pre-coding (weighted synthesis) is performed, and phase changes are performed on the obtained weighted synthesis signals 204A and 204B by phase change units 205A and 205B. Then, the post-phase-change signal 206A and the post-phase-change signal 206B are transmitted at the same frequency and at the same time. Therefore, in FIGS. 4 and 5, phase changes are performed on the data symbol 402 in FIG. 4 and the data symbol 502 in FIG. 5.

[0594] For example, FIG. 11 extracts carriers 1 to 5 and times $4 to $6 from the frame of FIG. 4. Similar to FIG. 4, 401 is a pilot symbol, 402 is a data symbol, and 403 is another symbol.

[0595] As described above, in the symbols shown in FIG. 11, the phase change unit 205A performs phase changes on the data symbols at (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 symbols shown in FIG. 11, the phase change value of the data symbol at (carrier 1, time $5) is "e j×λ15(i) ", the phase change value of the data symbol at (carrier 2, time $5) is "e j×λ25(i) ", the phase change value of the data symbol at (carrier 3, time $5) is "e j×λ35(i) ", the phase change value of the data symbol at (carrier 4, time $5) is "e j×λ45(i)」, and the phase change value of the data symbol at (carrier 5, time $5) is set to "e" j×λ55(i) 」, and the phase change value of the data symbol at (carrier 1, time $6) is set to "e" j×λ16(i) 」, and the phase change value of the data symbol at (carrier 2, time $6) is set to "e" j×λ26(i) 」, and the phase change value of the data symbol at (carrier 4, time $6) is set to "e" j×λ46(i) 」, and the phase change value of the data symbol at (carrier 5, time $6) is set to "e" j×λ56(i) 」.

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

[0598] This is a characteristic point of the phase change unit 205A. Note that, as shown in FIG. 4, 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), (carrier 5, time $6), which are the targets of phase change in FIG. 11, and "the same carrier, the same time", data carriers are arranged. That is, in FIG. 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, the data symbols performing MIMO transmission (transmitting a plurality of streams) are the targets of phase change of the phase change unit 205A.)

[0599] Note that, as an example of the phase change applied by the phase change unit 205A to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (50). (However, the phase change method applied to the data symbol is not limited to this.)

[0600] For example, FIG. 11 extracts carriers 1 to 5 and times $4 to $6 from the frame of FIG. 5. Similar to FIG. 5, 501 is a pilot symbol, 502 is a data symbol, and 503 is another symbol.

[0601] As described above, in the symbols shown in FIG. 11, the phase change unit 205B will perform phase changes 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 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) ".

[0603] 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.

[0604] This is a characteristic point of the phase change unit 205B. Note that 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), which are the targets of phase change in FIG. 11, and for "the same carrier, the same time", as shown in FIG. 4, data carriers are arranged. That is, in FIG. 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, the data symbols performing MIMO transmission (transmitting multiple streams) are the targets of phase change of the phase change unit 205B.)

[0605] Note that as an example of the phase change applied by the phase change unit 205B to the data symbol, there is a method of performing a regular (phase change period N) phase change on the data symbol as shown in Equation (2). (However, the phase change method applied to the data symbol is not limited to this.)

[0606] By doing so, in an environment where the direct wave is dominant, particularly in an LOS environment, it is possible to obtain the effect that the reception quality of data in the receiving device of the data symbol performing MIMO transmission (transmitting multiple streams) is improved. This effect will be described.

[0607] 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. 18 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 also 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.)

[0608] 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, and in the in-phase I - quadrature Q plane, 16 candidate signal points will exist. (Among the 16 candidate signal points, one is the signal point transmitted by the transmitting device. Therefore, it is called "16 candidate signal points".)

[0609] In an environment where the direct wave is dominant, especially in a LOS environment, Case 1: When the phase change units 205A and 205B in FIG. 22 do not exist (that is, when the phase change by the phase change units 205A and 205B in FIG. 22 is not performed) is considered.

[0610] 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", so in the receiving device of FIG. 8, the reception quality of the data may deteriorate.

[0611] To overcome this problem, in FIG. 22, phase change units 205A and 205B are inserted. When the phase change units 205A and 205B are inserted, due to symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number with "a long distance between signal points" as shown in FIG. 12(B) will be mixed. For this state, since an error correction code is introduced, a high error correction ability can be obtained, and in the receiving apparatus of FIG. 8, a high data reception quality can be obtained.

[0612] Note that in FIG. 22, for "pilot symbols, preambles", etc. for channel estimation for demodulating (detecting) data symbols, no phase change is performed in the phase change units 205A and 205B of FIG. 22. Thereby, in the data symbol, "due to symbol number i, a symbol number with a portion where signal points are dense (the distance between signal points is short) as shown in FIG. 12(A) and a symbol number with 'a long distance between signal points' as shown in FIG. 12(B) are mixed" can be realized.

[0613] However, for "pilot symbols, preambles," etc., which 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. 22, there may be a case where "in data symbols, a symbol number where a portion with dense signal points (short distance between signal points) as shown in FIG. 12(A) and a symbol number where 'the distance between signal points is long' as shown in FIG. 12(B) coexist" 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 change of data symbols can be established, and a method of "performing phase change on pilot symbols and / or preambles" can be considered. As an example, there is a method of regularly performing phase change with a period N on data symbols and regularly performing phase change with a period M on pilot symbols and / or preambles. (N and M are integers of 2 or more.)

[0614] 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 phase-changed signal 210A. Let the baseband signal 208A be a function of the symbol number i (where i is an integer of 0 or more) and be represented as x'(i). Then, the phase-changed signal 210A(x(i)) is x(i) = e j×ε(i)It can be expressed as ×x’(i) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209A, it is the point of performing phase change on the symbols existing in the frequency axis direction (performing phase change on 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 FIG. 22, since the phase change unit 209A performs phase change on the baseband signal 208A, phase change is performed on each symbol described in FIG. 4.)

[0615] Therefore, in the frame of FIG. 4, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 22 performs phase change.

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

[0617] As described above, the phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a phase change on the baseband signal 208B based on the control signal 200, and outputs the signal 210B after the phase change. Let the baseband signal 208B be a function of the symbol number i (where i is an integer greater than or equal to 0) and be represented as y'(i). Then, the signal 210B (y(i)) after the phase change is y(i)=e j×η(i)It can be expressed as ×y’(i) (j is the imaginary unit). As for the operation of the phase change unit 209B, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209B, it is to perform a phase change on the symbols existing in the frequency axis direction (perform a phase change on 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 FIG. 22, since the phase change unit 209B performs a phase change on the baseband signal 208B, a phase change is performed on each symbol described in FIG. 5.)

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

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

[0620] FIG. 13 has a different frame configuration from FIG. 4 of the transmission signal 108_A in FIG. 1. Since it was described in detail in Embodiment 1, the description is omitted.

[0621] FIG. 14 has a different frame configuration from FIG. 5 of the transmission signal 108_B in FIG. 1. Since it was described in detail in Embodiment 1, the description is omitted.

[0622] When there is a symbol at carrier A and time $B in FIG. 13, and when there is a symbol at carrier A and time $B in FIG. 14, the symbol at carrier A and time $B in FIG. 13 and the symbol at carrier A and time $B in FIG. 14 will be transmitted at the same time and the same frequency. Note that the frame configurations in FIGS. 13 and 14 are merely examples.

[0623] And the other symbols in FIGS. 13 and 14 are symbols corresponding to the "preamble signal 252 and control information symbol signal 253 in FIG. 22". Therefore, when the other symbol 503 in FIG. 14 at the same time and the same frequency (the same carrier) as the other symbol 403 in FIG. 13 is transmitting control information, it will be transmitting the same data (the same control information).

[0624] Although it is assumed that the receiving device will receive the frames of FIGS. 13 and 14 simultaneously, it is possible for the receiving device to obtain the data transmitted by the transmitting device by receiving only the frame of FIG. 13 or only the frame of FIG. 14.

[0625] 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 symbol number i (where i is an integer greater than or equal to 0) and be represented 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) (j is the imaginary unit). As for the operation of the phase change unit 209A, it may be CDD (Cyclic Delay Diversity) (CSD (Cyclic Shift Diversity)) described in Non-Patent Document 2 and Non-Patent Document 3. And as a feature of the phase change unit 209A, it is the point of performing phase change on the symbols existing in the frequency axis direction (phase change is performed on data symbols, pilot symbols, control information symbols, etc. At this time, null symbols can also be considered as objects of phase change. (Therefore, in this case, the symbols targeted by symbol number i are data symbols, pilot symbols, control information symbols, preambles (other symbols), null symbols, etc.). However, even if phase change is performed on null symbols, the signal before phase change and the signal after phase change are the same (the in-phase 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 objects of phase change. (In the case of FIG. 22, since the phase change unit 209A performs phase change on the baseband signal 208A, phase change is performed on each symbol described in FIG. 13.)

[0626] Therefore, in the frame of FIG. 13, for all symbols from carrier 1 to carrier 36 at time $1 (in this case, all become other symbols 403), the phase change unit 209A in FIG. 22 performs phase change. However, the handling of the phase change of the null symbol 1301 is as described before.

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

[0628] Let the phase change value in the phase change unit 209A be represented as Ω(i). 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."

[0629] For example, set the value of the phase change as in Equation (38). (Q is an integer of 2 or more, and Q is the period of the phase change.) (j is the imaginary unit) However, Equation (38) is merely an example and is not limited to this."

[0630] For example, Ω(i) may be set so that the phase change is performed with a period Q."

[0631] Also, for example, in FIGS. 4 and 13, it is also possible to give the same phase change value to the same carrier and set the phase change value for each carrier. For example, it becomes as follows." · For carrier 1 in FIGS. 4 and 13, regardless of time, the phase change value is set as in Equation (39). · For carrier 2 in FIGS. 4 and 13, regardless of time, the phase change value is set as in Equation (40). · For carrier 3 in FIGS. 4 and 13, regardless of time, the phase change value is set as in Equation (41). ·For the carrier 4 in FIGS. 4 and 13, regardless of the time, the phase change value is given by Equation (42). ···

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

[0633] The phase change unit 209B takes the baseband signal 208B and the control signal 200 as inputs, performs a ...

Claims

1. A transmission device comprising a mapping unit, a signal processing unit, and a transmission unit, wherein the mapping unit, in operation, when the first precoding is effective, generates a plurality of first symbols by modulating a bit sequence, and when the first precoding is not effective, generates a second symbol and a third symbol by modulating a bit sequence, the signal processing unit, in operation, when the first precoding is effective, generates a plurality of precoded symbols, which are weighted sums of the plurality of first symbols respectively, by performing the first precoding on the plurality of first symbols, and when the first precoding is not effective, generates 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 a second precoding on the second symbol and the third symbol, the transmission unit, in operation, transmits the precoded first symbols, or the second and third precoded symbols, and each of the plurality of precoded first symbols is mapped onto different transmission resources identified by at least one of frequency and time, transmission device.

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

3. The first precoding and the second precoding are performed based on the same precoding matrix, The transmission device according to claim 1.

4. A transmission method performed by a transmission device, When the first precoding is valid, generating a plurality of first symbols by modulating a bit sequence, When the first precoding is not valid, a first step of generating a second symbol and a third symbol by modulating a bit sequence, When the first precoding is valid, by performing the first precoding on the plurality of first symbols, generating a plurality of first precoded symbols that are weighted sums of the plurality of first symbols respectively, When the first precoding is not valid, by performing a second precoding on the second symbol and the third symbol, generating a second precoded symbol that is a weighted sum of the second symbol and the third symbol, and a third precoded symbol that is a weighted sum of the second symbol and the third symbol, a second step, A third step of transmitting the first precoded symbols, or the second precoded symbol and the third precoded symbol, including Each of the plurality of first precoded symbols is mapped onto different transmission resources identified by at least one of frequency and time. Transmission method.

5. In the third step, an 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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