TRANSMISSION DEVICE AND TRANSMISSION METHOD

Description

Technical Field

[0001] The present disclosure relates to a transmission apparatus and a transmission method.Background Art

[0002] A communication method called Multiple-Input Multiple-Output (MIMO), for example, is known as a communication method using multiple antennas. In multi-antenna communication for a single user represented by MIMO, multiple sequences of transmission data are individually modulated, modulated signals obtained accordingly are simultaneously transmitted from different antennas, and thus the data communication speed is increased.

[0003] Fig. 33 is a diagram illustrating an example of the configuration of a transmission apparatus that is based on the Digital Video Broadcasting-Next Generation Handheld (DVB-NGH) standard in a case where the number of transmission antennas is two and the number of modulated transmission signals (transmission streams) is two, which is described in NPL 1. In the transmission apparatus, data 1 is input and coded by an encoder 2 to obtain data 3, which is divided into data 5A and data 5B by a distributer 4. The data 5A is subjected to interleaving processing performed by an interleaver 4A and mapping processing performed by a mapper 6A. Likewise, the data 5B is subjected to interleaving processing performed by an interleaver 4B and mapping process performed by a mapper 6B. The coding processing in the encoder 2, the interleaving processing in the interleavers 4A and 4B, and the mapping processing in the mappers 6A and 6B are performed on the basis of setting information included in a frame configuration signal 13.

[0004] Weight combiners 8A and 8B receive mapped signals 7A and 7B and perform weight combining thereon to generate weight combined signals 9A and 16B, respectively. After that, the weight combined signal 16B is subjected to phase change performed by a phase changer 17B, and a phase-changed signal 9B is output. Subsequently, radio sections 10A and 10B perform, for example, processing related to orthogonal frequency division multiplexing (OFDM), such as frequency conversion and amplification. In addition, a transmission signal 11A is transmitted from an antenna 12A, and a transmission signal 11B is transmitted from an antenna 12B. The weight combining processing in the weight combiners 8A and 8B and the phase change processing in the phase changer 17B are performed on the basis of signal processing method information 115 generated by a signal processing method information generator 114. The signal processing method information generator 114 generates the signal processing method information 115 on the basis of the frame configuration signal 13. At this time, in the phase changer 17B, for example, nine phase change values are provided and phase change in a period of 9 is regularly performed.

[0005] Accordingly, there is a high possibility of being able to avoid a situation where a reception apparatus as a communication partner falls into a steady reception state in an environment in which direct waves are dominant. Accordingly, it is possible to improve the data reception quality at the reception apparatus as a communication partner.Citation ListNon Patent Literature

[0006] NPL 1: "MIMO for DVB-NGH, the next generation mobile TV broadcasting," IEEE Commun. Mag., vol. 57, no. 7, pp. 130-137, July 2013. NPL 2: Standard conformable antenna diversity techniques for OFDM and its application to the DVB-T system," IEEE Globecom 2001, pp. 3100-3105, Nov. 2001. NPL 3: IEEE P802. 11n (D3.00) Draft STANDARD for Information Technology-Telecommunications and information exchange between systems-Local and metropoitan area networks-Specific requirements-Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, 2007.

[0007] US 2016 / 204846 A1 relates to transmission of modulated signals using MIMO. In particular, as shown in Fig. 3, two chains of encoders, interleavers, and mappers, take respective data 301A and 301B and output respective baseband signals 307A and 307B, such as QPSK-modulated signals. Baseband signal 307A and baseband signal 307B are both passed to two respective weighting units 308A and 308B, and the output of the weighting units is respectively transmitted by a first and a second antenna, 312A and 312B. The signal output by the second weighting unit 308B is passed to a phase changer 317B before being transmitted.

[0008] European Patent Application EP17806407A, which is state of the art in accordance with Article 54(3) EPC, relates to a transmission apparatus and a transmission method.Summary of Invention

[0009] However, the transmission apparatus in Fig. 33 does not consider transmitting modulated signals to multiple terminals (multiple users) using identical times and identical frequencies (identical frequency bands).

[0010] Accordingly, an aspect of the present disclosure provides a transmission apparatus capable of transmitting modulated signals to multiple terminals (multiple users) by using identical times and identical frequencies (identical frequency bands). In particular, when transmitting modulated signals of multiple streams to the individual terminals (individual users), it is possible to avoid a situation where a reception apparatus as a communication partner falls into a steadily poor reception state in an environment in which direct waves are dominant. Accordingly, the data reception quality at the reception apparatus as a communication partner is improved.

[0011] The invention is defined by the features of the independent claims.

[0012] It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a recording medium, or any selective combination thereof.

[0013] According to an aspect of the present disclosure, when transmitting modulated signals of multiple streams to individual terminals (individual users), it is possible to avoid a situation where each terminal falls into a steadily poor reception state in an environment in which direct waves are dominant. Accordingly, it is possible to improve the data reception quality in a reception apparatus as a communication partner.Brief Description of Drawings

[0014] [Fig. 1] Fig. 1 is a diagram illustrating an example of the configuration of a transmission apparatus according to an embodiment of the present disclosure. [Fig. 2] Fig. 2 is a diagram illustrating an example of the configuration of a signal processor for a user #p. [Fig. 3] Fig. 3 is a diagram illustrating an example of the configuration of the signal processor in Fig. 2. [Fig. 4] Fig. 4 is a diagram illustrating an example of the configuration of the signal processor in Fig. 2 different from Fig. 3. [Fig. 5] Fig. 5 is a diagram illustrating an example of the configuration of a radio section $n that uses the OFDM scheme. [Fig. 6] Fig. 6 is a diagram illustrating an example of the configuration of an antenna section in Fig. 1. [Fig. 7] Fig. 7 is a diagram illustrating an example of the configuration of a portion related to control information generation for generating a control information symbol signal in Figs. 3 and 4. [Fig. 8] Fig. 8 is a diagram illustrating an example of the frame configuration of a first baseband signal for the user #p. [Fig. 9] Fig. 9 is a diagram illustrating an example of the frame configuration of a second baseband signal for the user #p. [Fig. 10] Fig. 10 is a diagram illustrating another example of the frame configuration of the first baseband signal for the user #p. [Fig. 11] Fig. 11 is a diagram illustrating another example of the frame configuration of the second baseband signal for the user #p. [Fig. 12] Fig. 12 is a diagram illustrating an example of a method for arranging symbols with respect to a time axis. [Fig. 13] Fig. 13 is a diagram illustrating an example of a method for arranging symbols with respect to a frequency axis. [Fig. 14] Fig. 14 is a diagram illustrating an example of arrangement of symbols with respect to the time and frequency axes. [Fig. 15] Fig. 15 is a diagram illustrating an example of arrangement of symbols with respect to the time axis. [Fig. 16] Fig. 16 is a diagram illustrating an example of arrangement of symbols with respect to the frequency axis. [Fig. 17] Fig. 17 is a diagram illustrating an example of arrangement of symbols with respect to the time and frequency axes. [Fig. 18] Fig. 18 is a diagram illustrating the configuration of a multiplexing signal processor that includes an interleaver. [Fig. 19] Fig. 19 is a diagram illustrating an example of the configuration of a reception apparatus according to the present embodiment. [Fig. 20] Fig. 20 is a diagram illustrating the relationship between the transmission apparatus and the reception apparatus. [Fig. 21] Fig. 21 is a diagram illustrating an example of the configuration of the antenna section in Fig. 19. [Fig. 22] Fig. 22 is a diagram illustrating an example of the configuration of a base station (AP) including the transmission apparatus in Fig. 1. [Fig. 23] Fig. 23 is a diagram illustrating an example of the configuration of a terminal including the reception apparatus in Fig. 19. [Fig. 24] Fig. 24 is a diagram illustrating an example of the relationship between the base station (AP) and terminals. [Fig. 25] Fig. 25 is a diagram illustrating an example of a temporal flow of communication between the base station (AP) and the terminals. [Fig. 26] Fig. 26 is a diagram illustrating an example of the configuration of the signal processor in Fig. 2 different from Fig. 3. [Fig. 27] Fig. 27 is a diagram illustrating an example of communication between the base station (AP) and a terminal #p. [Fig. 28] Fig. 28 is a diagram illustrating an example of data included in a reception capability notification symbol. [Fig. 29] Fig. 29 is a diagram illustrating an example of data included in the reception capability notification symbol different from Fig. 28. [Fig. 30] Fig. 30 is a diagram illustrating an example of data included in the reception capability notification symbol different from Figs. 28 and 29. [Fig. 31] Fig. 31 is a diagram illustrating an example of the configuration of the signal processor for the user #p. [Fig. 32] Fig. 32 is a diagram illustrating an example of the configuration of the signal processor for the user #p. [Fig. 33] Fig. 33 is a diagram illustrating an example of the configuration of a transmission apparatus that is based on the DVB-NGH standard described in NPL 1. [Fig. 34] Fig. 34 is a diagram illustrating an example of the configuration of the terminal #p as a communication partner of the base station illustrated in Fig. 24. [Fig. 35] Fig. 35 is a diagram illustrating an example of the configuration of the reception apparatus of the terminal #p illustrated in Fig. 34. [Fig. 36] Fig. 36 is a diagram illustrating an example of the frame configuration of a modulated signal of a single stream transmitted by using a multi-carrier transmission scheme such as the OFDM scheme. [Fig. 37] Fig. 37 is a diagram illustrating an example of the frame configuration of a modulated signal of a single stream transmitted by using a single-carrier transmission scheme. [Fig. 38] Fig. 38 is a diagram illustrating still another example of the configuration of the signal processor in Fig. 2. [Fig. 39] Fig. 39 is a diagram illustrating still another example of the configuration of the signal processor in Fig. 2. [Fig. 40] Fig. 40 is a diagram illustrating a first example in which phase changers are arranged upstream and downstream of a weight combiner. [Fig. 41] Fig. 41 is a diagram illustrating a second example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 42] Fig. 42 is a diagram illustrating a third example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 43] Fig. 43 is a diagram illustrating a fourth example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 44] Fig. 44 is a diagram illustrating a fifth example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 45] Fig. 45 is a diagram illustrating a sixth example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 46] Fig. 46 is a diagram illustrating a seventh example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 47] Fig. 47 is a diagram illustrating an eighth example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 48] Fig. 48 is a diagram illustrating a ninth example in which phase changers are arranged upstream and downstream of the weight combiner. [Fig. 49] Fig. 49 is a diagram illustrating a first example configuration on the output side of an inserter. [Fig. 50] Fig. 50 is a diagram illustrating a second example configuration on the output side of the inserter. [Fig. 51] Fig. 51 is a diagram illustrating a third example configuration on the output side of the inserter. [Fig. 52] Fig. 52 is a diagram illustrating a fourth example configuration on the output side of the inserter. [Fig. 53] Fig. 53 is a diagram illustrating a fifth example configuration on the output side of the inserter. [Fig. 54] Fig. 54 is a diagram illustrating a sixth example configuration on the output side of the inserter. [Fig. 55] Fig. 55 is a diagram for describing CDD (CSD). [Fig. 56] Fig. 56 is a diagram illustrating an example of the configuration of the signal processor for the user #p different from Fig. 2. [Fig. 57] Fig. 57 is a diagram illustrating a first example of the operation of a mapper. [Fig. 58] Fig. 58 is a diagram illustrating a first example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. [Fig. 59] Fig. 59 is a diagram illustrating a second example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. [Fig. 60] Fig. 60 is a diagram illustrating a third example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. [Fig. 61] Fig. 61 is a diagram illustrating a fourth example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. [Fig. 62] Fig. 62 is a diagram illustrating an example of the configuration of the signal processor for the user #p different from Figs. 2 and 56. [Fig. 63] Fig. 63 is a diagram illustrating a second example of the operation of the mapper. [Fig. 64] Fig. 64 is a diagram illustrating a third example of the operation of the mapper. [Fig. 65] Fig. 65 is a diagram illustrating a fourth example of the operation of the mapper. [Fig. 66] Fig. 66 is a diagram illustrating a fifth example of the operation of the mapper. [Fig. 67] Fig. 67 is a diagram illustrating a sixth example of the operation of the mapper. [Fig. 68A] Fig. 68A is a diagram illustrating a first example of the state of signal points of signals transmitted by the transmission apparatus including the configuration in Fig. 3. [Fig. 68B] Fig. 68B is a diagram illustrating a first example of the state of signal points of signals received by the reception apparatus as a communication partner of the transmission apparatus including the configuration in Fig. 3. [Fig. 69A] Fig. 69A is a diagram illustrating a second example of the state of signal points of signals transmitted by the transmission apparatus including the configuration in Fig. 3. [Fig. 69B] Fig. 69B is a diagram illustrating a second example of the state of signal points of signals received by the reception apparatus as a communication partner of the transmission apparatus including Fig. 3. [Fig. 70] Fig. 70 is a diagram illustrating an example configuration of the transmission apparatus of the base station (AP) different from Fig. 1. [Fig. 71] Fig. 71 is a diagram illustrating an example of data included in the reception capability notification symbol different from Figs. 28, 29, and 30. [Fig. 72] Fig. 72 is a diagram illustrating an example of the configuration of a frame. [Fig. 73] Fig. 73 is a diagram illustrating an example of carrier groups of modulated signals transmitted by the base station or AP. [Fig. 74] Fig. 74 is a diagram illustrating an example of carrier groups of modulated signals transmitted by the base station or AP different from Fig. 73. [Fig. 75] Fig. 75 is a diagram illustrating an example of a configuration added with a phase changer. [Fig. 76] Fig. 76 is a diagram illustrating a first example configuration of the signal processor for the user #p in Figs. 1 and 70. [Fig. 77] Fig. 77 is a diagram illustrating a second example configuration of the signal processor for the user #p in Figs. 1 and 70. [Fig. 78] Fig. 78 is a diagram illustrating a first example of the configuration included in control information symbols or the like. [Fig. 79] Fig. 79 is a diagram illustrating a second example of the configuration included in control information symbols or the like. [Fig. 80] Fig. 80 is a diagram illustrating a specific example configuration of the reception capability notification symbol transmitted by the terminal #p illustrated in Fig. 27. [Fig. 81] Fig. 81 is a diagram illustrating an example of the configuration of "single-carrier scheme and OFDM scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 82] Fig. 82 is a diagram illustrating an example of the configuration of "single-carrier scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 83] Fig. 83 is a diagram illustrating an example of the configuration of "OFDM scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 84] Fig. 84 is a diagram illustrating another example of a specific configuration of the reception capability notification symbol transmitted by the terminal #p illustrated in Fig. 27. [Fig. 85] Fig. 85 is a diagram illustrating an example of the configuration of "OFDM scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 86] Fig. 86 is a diagram illustrating an example of the configuration of "OFDM scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 87] Fig. 87 is a diagram illustrating an example of the configuration of "OFDM scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 88] Fig. 88 is a diagram illustrating an example of the configuration of "OFDM scheme related reception capability notification symbol" illustrated in Fig. 80. [Fig. 89] Fig. 89 is a diagram illustrating an example of the format of the reception capability notification symbol. [Fig. 90] Fig. 90 is a diagram illustrating an example of the format of an Extended Capabilities field. [Fig. 91] Fig. 91 is a diagram illustrating a first example of the Extended Capabilities field. [Fig. 92] Fig. 92 is a diagram illustrating a second example of the Extended Capabilities field. [Fig. 93] Fig. 93 is a diagram illustrating a third example of the Extended Capabilities field. [Fig. 94] Fig. 94 is a diagram illustrating a fourth example of the Extended Capabilities field. [Fig. 95] Fig. 95 is a diagram illustrating a fifth example of the Extended Capabilities field. [Fig. 96] Fig. 96 is a diagram illustrating an example of data included in the reception capability notification symbol. [Fig. 97] Fig. 97 is a diagram illustrating another example of data included in the reception capability notification symbol. [Fig. 98] Fig. 98 is a diagram illustrating still another example of data included in the reception capability notification symbol. [Fig. 99] Fig. 99 is a diagram illustrating still another example of data included in the reception capability notification symbol. [Fig. 100] Fig. 100 is a diagram illustrating still another example of data included in the reception capability notification symbol. [Fig. 101] Fig. 101 is a diagram illustrating still another example of data included in the reception capability notification symbol. [Fig. 102] Fig. 102 is a diagram illustrating an example of the configuration of a first signal processor. [Fig. 103] Fig. 103 is a diagram illustrating an example of the configuration of a second signal processor. [Fig. 104] Fig. 104 is a diagram illustrating an example of the relationship between the base station (AP) and the terminal. [Fig. 105] Fig. 105 is a diagram illustrating an example configuration of the transmission apparatus of the base station (AP) different from Fig. 1. Description of Embodiments

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The individual embodiments described below are examples, and the present disclosure is not limited to these embodiments. The scope of the invention is defined by the appended claims, which correspond to the example configuration of figure 3, the ninth embodiment of figure 41 and the thirtieth embodiment of figure 105.(First Embodiment)

[0016] A detailed description will be given of a transmission method, a transmission apparatus, a reception method, and a reception apparatus according to the present embodiment.<Example of Configuration of Transmission Apparatus in Present Embodiment>

[0017] Fig. 1 is a diagram illustrating an example of the configuration of the transmission apparatus in the present embodiment. The transmission apparatus illustrated in Fig. 1 is, for example, a base station, an access point, a broadcast station, or the like. The transmission apparatus is a transmission apparatus that generates modulated signals to be transmitted to a user #1 reception apparatus (terminal) to a user #M reception apparatus (terminal) (M is an integer equal to or greater than 2) and transmits the modulated signals.

[0018] The transmission apparatus illustrated in Fig. 1 includes a user #1 signal processor 102_1 to a user #M signal processor 102_M, a multiplexing signal processor 104, a radio section $1 (106_1) to a radio section $N (106_N), and an antenna section $1 (108_1) to an antenna section $N (108_N) (N is an integer equal to or greater than 1).

[0019] The user #1 signal processor 102_1 receives a control signal 100 and user #1 data 101_1. On the basis of information about a transmission method for generating a user #1 modulated signal included in the control signal 100, the user #1 signal processor 102_1 performs signal processing and generates a user #1 first baseband signal 103_1_1 and / or a user #1 second baseband signal 103_1_2. The user #1 signal processor 102_1 outputs the generated user #1 first baseband signal 103_1_1 and / or user #1 second baseband signal 103_1_2 to the multiplexing signal processor 104. The transmission method for generating a modulated signal includes, for example, an error-correcting coding method (the code rate of an error-correcting code and the code length of the error-correcting code), a modulation scheme, a transmission method (for example, single-stream transmission and multi-stream transmission), and the like.

[0020] For example, in a case where the control signal 100 includes information indicating that multi-stream transmission is selected, the user #1 signal processor 102_1 generates the user #1 first baseband signal 103_1_1 and the user #1 second baseband signal 103_1_2. In a case where the control signal 100 includes information indicating that single-stream transmission is selected, the user #1 signal processor 102_1 generates the user #1 first baseband signal 103_1_1.

[0021] Likewise, the user #2 signal processor 102_2 receives the control signal 100 and user #2 data 101_2. On the basis of information about a transmission method for generating a user #2 modulated signal included in the control signal 100, the user #2 signal processor 102_2 performs signal processing and generates a user #2 first baseband signal 103_2_1 and / or a user #2 second baseband signal 103_2_2. The user #2 signal processor 102_2 outputs the generated user #2 first baseband signal 103_2_1 and / or user #2 second baseband signal 103_2_2 to the multiplexing signal processor 104. The transmission method for generating a modulated signal includes, for example, an error-correcting coding method (the code rate of an error-correcting code and the code length of the error-correcting code), a modulation scheme, a transmission method (for example, single-stream transmission and multi-stream transmission), and the like.

[0022] For example, in a case where the control signal 100 includes information indicating that multi-stream transmission is selected, the user #2 signal processor 102_2 generates the user #2 first baseband signal 103_2_1 and the user #2 second baseband signal 103_2_2. In a case where the control signal 100 includes information indicating that single-stream transmission is selected, the user #2 signal processor 102_2 generates the user #2 first baseband signal 103_2_1.

[0023] Likewise, the user #M signal processor 102_M receives the control signal 100 and user #M data 101_M. On the basis of information about a transmission method for generating a user #M modulated signal included in the control signal 100, the user #1 signal processor 102_1 performs signal processing and generates a user #M first baseband signal 103_M_1 and / or a user #M second baseband signal 103_M_2. The user #M signal processor 102_M outputs the generated user #M first baseband signal 103_M_1 and / or user #M second baseband signal 103_M_2 to the multiplexing signal processor 104. The transmission method for generating a modulated signal includes, for example, an error-correcting coding method (the code rate of an error-correcting code and the code length of the error-correcting code), a modulation scheme, a transmission method (for example, single-stream transmission and multi-stream transmission), and the like.

[0024] For example, in a case where the control signal 100 includes information indicating that multi-stream transmission is selected, the user #M signal processor 102_M generates the user #M first baseband signal 103_M_1 and the user #M second baseband signal 103_M_2. In a case where the control signal 100 includes information indicating that single-stream transmission is selected, the user #M signal processor 102_M generates the user #M first baseband signal 103_M_1.

[0025] Accordingly, a user #p signal processor 102_p (p is an integer from 1 to M) receives the control signal 100 and user #p data 101_p. On the basis of information about a transmission method for generating a user #p modulated signal (for example, an error-correcting coding method (the code rate of an error-correcting code and the code length of the error-correcting code), a modulation scheme, a transmission method (for example, single-stream transmission and multi-stream transmission), and the like) included in the control signal 100, the user #p signal processor 102_p performs signal processing and generates a user #p first baseband signal 103_p_1 and / or a user #p second baseband signal 103_p_2. The user #p signal processor 102_p outputs the generated user #p first baseband signal 103_p_1 and / or user #p second baseband signal 103_p_2 to the multiplexing signal processor 104.

[0026] For example, in a case where the control signal 100 includes information indicating that multi-stream transmission is selected, the user #p signal processor 102_p generates the user #p first baseband signal 103_p_1 and the user #p second baseband signal 103_p_2. In a case where the control signal 100 includes information indicating that single-stream transmission is selected, the user #p signal processor 102_p generates the user #p first baseband signal 103_p_1.

[0027] The configuration of each of the user #1 signal processor 102_1 to the user #M signal processor 102_M will be described below by taking the configuration of the user #p signal processor as an example.

[0028] The control signal 100 includes information indicating which of multi-stream transmission and single-stream transmission is selected for each of the user #1 signal processor 102_1 to the user #M signal processor 102_M.

[0029] The multiplexing signal processor 104 receives the control signal 100, the user #1 first baseband signal 103_1_1, the user #1 second baseband signal 103_1_2, the user #2 first baseband signal 103_2_1, the user #2 second baseband signal 103_2_2, ···, the user #M first baseband signal 103_M_1, the user #M second baseband signal 103_M_2, and a (common) reference signal 199. On the basis of the control signal 100, the multiplexing signal processor 104 performs multiplexing signal processing and generates a multiplexed signal $1 baseband signal 105_1 to a multiplexed signal $N baseband signal 105_N (N is an integer equal to or greater than 1). The multiplexing signal processor 104 outputs the generated multiplexed signal $1 baseband signal 105_1 to multiplexed signal $N baseband signal 105_N to the corresponding radio sections (the radio section $1 to the radio section $N).

[0030] The (common) reference signal 199 is a signal that is transmitted from the transmission apparatus for the reception apparatus to estimate a propagation environment. The (common) reference signal 199 is inserted into the baseband signal of each user. The multiplexing signal processing will be described below.

[0031] The radio section $1 (106_1) receives the control signal 100 and the multiplexed signal $1 baseband signal 105_1. On the basis of the control signal 100, the radio section $1 (106_1) performs processing such as frequency conversion and amplification, and outputs a transmission signal 107_1 to the antenna section $1 (108_1).

[0032] The antenna section $1 (108_1) receives the control signal 100 and the transmission signal 107_1. On the basis of the control signal 100, the antenna section $1 (108_1) performs processing on the transmission signal 107_1. Note that, in the antenna section $1 (108_1), the control signal 100 need not necessarily exist as input. The transmission signal 107_1 is output as a radio wave from the antenna section $1 (108_1).

[0033] The radio section $2 (106_2) receives the control signal 100 and the multiplexed signal $2 baseband signal 1020p5_2. On the basis of the control signal 100, the radio section $2 (106_2) performs processing such as frequency conversion and amplification, and outputs a transmission signal 107_2 to the antenna section $2 (108_2).

[0034] The antenna section $2 (108_2) receives the control signal 100 and the transmission signal 107_2. On the basis of the control signal 100, the antenna section $2 (108_2) performs processing on the transmission signal 107_2. Note that, in the antenna section $2 (108_2), the control signal 100 need not necessarily exist as input. The transmission signal 107_2 is output as a radio wave from the antenna section $2 (108_2).

[0035] The radio section $N (106_N) receives the control signal 100 and the multiplexed signal $N baseband signal 105_N. On the basis of the control signal 100, the radio section $N (106_N) performs processing such as frequency conversion and amplification, and outputs a transmission signal 107_N to the antenna section $N (108_N).

[0036] The antenna section $N (108_N) receives the control signal 100 and the transmission signal 107_N. On the basis of the control signal 100, the antenna section $N (108_N) performs processing on the transmission signal 107_N. Note that, in the antenna section $N (108_N), the control signal 100 need not necessarily exist as input. The transmission signal 107_N is output as a radio wave from the antenna section $N (108_N).

[0037] Accordingly, a radio section $n (106_n) (n is an integer from 1 to N) receives the control signal 100 and a multiplexed signal $n baseband signal 105_n. On the basis of the control signal 100, the radio section $n (106_n) performs processing such as frequency conversion and amplification, and outputs a transmission signal 107_n to an antenna section $n (108_n).

[0038] The antenna section $n (108_n) receives the control signal 100 and the transmission signal 107_n. On the basis of the control signal 100, the antenna section $n (108_n) performs processing on the transmission signal 107_n. Note that, in the antenna section $n (108_n), the control signal 100 need not necessarily exist as input. The transmission signal 107_n is output as a radio wave from the antenna section $n (108_n).

[0039] An example of the configurations of the radio sections $1 to $N and the antenna sections $1 to $N will be described below.

[0040] The control signal 100 may be generated on the basis of information transmitted to the transmission apparatus in Fig. 1 by the reception apparatus as a communication partner of Fig. 1. Alternatively, the transmission apparatus in Fig. 1 may include an input section, and the control signal 100 may be generated on the basis of information input from the input section.

[0041] In the transmission apparatus in Fig. 1, not all the user #1 signal processor (102_1) to the user #M signal processor (102_M) may be operating. All of them may be operating or some of them may be operating. That is, the number of users with which the transmission apparatus is communicating is 1 to M. The number of communication partners (users) to which the transmission apparatus in Fig. 1 transmits a modulated signal is 1 to M.

[0042] Also, not all the radio section $1 (106_1) to the radio section $N (106_N) may be operating. All of them may be operating or some of them may be operating. Also, not all the antenna section $1 (108_1) to the antenna section $N (108_N) may be operating. All of them may be operating or some of them may be operating.

[0043] As described above, the transmission apparatus in Fig. 1 is able to transmit modulated signals (baseband signals) for multiple users by using identical times and identical frequencies (bands) and by using multiple antennas.

[0044] For example, the transmission apparatus in Fig. 1 is able to transmit the user #1 first baseband signal 103_1_1, the user #1 second baseband signal 103_1_2, the user #2 first baseband signal 103_2_1, and the user #2 second baseband signal 103_2_2 by using identical times and identical frequencies (bands). Also, the transmission apparatus in Fig. 1 is able to transmit the user #1 first baseband signal 103_1_1, the user #1 second baseband signal 103_1_2, and the user #2 first baseband signal 103_2_1 by using identical times and identical frequencies (bands). The combination of modulated signals (baseband signals) for multiple users transmitted by the transmission apparatus in Fig. 1 is not limited to the foregoing examples.<Example of Configuration of User #p Signal Processor>

[0045] Next, a description will be given of the configuration of each of the user #1 signal processor 102_1 to the user #M signal processor 102_M in Fig. 1 by taking the configuration of the user #p signal processor 102_p as an example. Fig. 2 is a diagram illustrating an example of the configuration of the user #p signal processor 102_p.

[0046] The user #p signal processor 102_p includes an error-correcting encoder 202, a mapper 204, and a signal processor 206.

[0047] The error-correcting encoder 202 receives user #p data 201 and a control signal 200. The control signal 200 corresponds to the control signal 100 in Fig. 1, and the user #p data 201 corresponds to the user #p data 101_p in Fig. 1. On the basis of information about an error-correcting code (for example, error-correcting code information, a code length (block length), and a code rate) included in the control signal 200, the error-correcting encoder 202 performs error-correcting coding, and outputs user #p coded data 203 to the mapper 204.

[0048] The error-correcting encoder 202 may include an interleaver. In a case where the error-correcting encoder 202 includes an interleaver, the error-correcting encoder 202 sorts data after coding the data and outputs the user #p coded data 203.

[0049] The mapper 204 receives the user #p coded data 203 and the control signal 200. On the basis of information about a modulation scheme included in the control signal 200, the mapper 204 performs mapping corresponding to the modulation scheme, and generates a user #p mapped signal (baseband signal) 205_1 and / or mapped signal (baseband signal) 205_2. The mapper 204 outputs the generated user #p mapped signal (baseband signal) 205_1 and / or mapped signal (baseband signal) 205_2 to the signal processor 206.

[0050] In a case where the control signal 200 includes information indicating that multi-stream transmission is selected, the mapper 204 divides the user #p coded data 203 into a first sequence and a second sequence. Subsequently, the mapper 204 generates the user #p mapped signal 205_1 by using the first sequence and generates the user #p mapped signal 205_2 by using the second sequence. At this time, it is assumed that the first sequence and the second sequence are different from each other. However, the operation can be performed similarly even if the first sequence and the second sequence are identical to each other.

[0051] In a case where the control signal 200 includes information indicating that multi-stream transmission is selected, the mapper 204 may divide the user #p coded data 203 into three or more sequences, perform mapping by using the individual sequences, and generate three or more mapped signals. In this case, the three or more sequences may be different from one another, or some or all of the three or more sequences may be identical to one another.

[0052] In a case where the control signal 100 includes information indicating that single-stream transmission is selected, the mapper 204 generates the user #p mapped signal 205_1 by using the user #p coded data 203 as one sequence.

[0053] The signal processor 206 receives the user #p mapped signal 205_1 and / or the user #p mapped signal 205_2, a signal group 210, and the control signal 200. On the basis of the control signal 200, the signal processor 206 performs signal processing, and outputs user #p processed signals 207_A and 207_B. The user #p processed signal 207_A corresponds to the user #p first baseband signal 103_p_1 in Fig. 1, and the user #p processed signal 207_B corresponds to the user #p first baseband signal 103_p_2 in Fig. 1.

[0054] At this time, the user #p processed signal 207_A is represented by up1(i), and the user #p processed signal 207_B is represented by up2(i). Here, i is a symbol number and is, for example, an integer equal to or greater than 0.

[0055] Next, the configuration of the signal processor 206 in Fig. 2 will be described with reference to Fig. 3.<Example of Configuration of Signal Processor 206>

[0056] Fig. 3 is a diagram illustrating an example of the configuration of the signal processor 206 in Fig. 2. The signal processor 206 includes a weight combiner 303, a phase changer 305B, an inserter 307A, an inserter 307B, and a phase changer 309B. In Fig. 3, a description will be given of a case where the mapper 204 has generated the user #p mapped signal 205_1 and the user #p mapped signal 205_2 in Fig. 2 on the basis of information indicating that multi-stream transmission is selected.

[0057] The weight combiner (precoder) 303 receives a user #p mapped signal 301A, a user #p mapped signal 301B, and a control signal 300. The user #p mapped signal 301A corresponds to the user #p mapped signal 205_1 in Fig. 2, and the user #p mapped signal 301B corresponds to the user #p mapped signal 205_2 in Fig. 2. The control signal 300 corresponds to the control signal 200 in Fig. 2.

[0058] On the basis of the control signal 300, the weight combiner 303 performs weight combining (precoding) and generates a user #p weighted signal 304A and a user #p weighted signal 304B. The weight combiner 303 outputs the user #p weighted signal 304A to the inserter 307A. The weight combiner 303 outputs the user #p weighted signal 304B to the phase changer 305B.

[0059] The user #p mapped signal 301A is represented by sp1(t), the user #p mapped signal 301B is represented by sp2(t), the user #p weighted signal 304A is represented by zp1(t), and the user #p weighted signal 304B is represented by zp2'(t). Here, t represents time, for example. In addition, sp1(t), sp2(t), zp1(t), and zp2'(t) are defined as complex numbers. Thus, sp1(t), sp2(t), zp1(t), and zp2'(t) may be real numbers.

[0060] In this case, the weight combiner 303 performs computation that is based on the following Expression (1). [Math. 1] zp 1 i zp 2 ′ i = a b c d sp 1 i sp 2 i In Expression (1), a, b, c, and d are defined as complex numbers, and may be real numbers. Note that i is a symbol number.

[0061] The phase changer 305B receives the weighted signal 304B and the control signal 300. On the basis of the control signal 300, the phase changer 305B performs phase change on the weighted signal 304B, and outputs a phase-changed signal 306B to the inserter 307B. The phase-changed signal 306B is represented by zp2(t). zp2(t) is defined as a complex number, and may be a real number.

[0062] A specific operation of the phase changer 305B will be described. It is assumed that the phase changer 305B performs phase change of yp(i) on zp2'(i), for example. This can be expressed by zp2(i) = yp(i)×zp2'(i). Here, i is a symbol number (i is an integer equal to or greater than 0).

[0063] For example, the phase changer 305B sets the value of phase change expressed as yp(i) as in the following Expression (2). [Math. 2] y p i = e j 2 × π × i Np In Expression (2), j is the imaginary unit. In addition, Np is an integer equal to or greater than 2 and represents the period of phase change. When Np is set to an odd number equal to or greater than 3, the data reception quality may be improved. However, Expression (2) is merely an example, and the value of phase change set in the phase changer 305B is not limited thereto. Thus, the phase change value is expressed by yp(i) = e j×δp(i)< .

[0064] At this time, zp1(i) and zp2(i) can be expressed by the following Expression (3) by using the phase change value yp(i) = e j×δp(i)< and Expression (1). [Math. 3] zp 1 i zp 2 i = 1 0 0 yp i zp 1 i zp 2 ′ i = 1 0 0 yp i a b c d sp 1 i sp 2 i = 1 0 0 e j × δp i a b c d sp 1 i sp 2 i Here, δp(i) is a real number. In addition, zp1(i) and zp2(i) are transmitted from the transmission apparatus at identical times and identical frequencies (identical frequency bands).

[0065] In Expression (3), the phase change value yp(i) is not limited to that expressed by Expression (2). For example, a method of changing the phase periodically or regularly may be used.

[0066] A description will be given of a matrix used in the computation by the weight combiner 303 expressed by Expression (1) and Expression (3). The matrix used in the computation by the weight combiner 303 is represented by Fp, as expressed by the following Expression (4). [Math. 4] a b c d = Fp

[0067] For example, any of the matrices expressed by the following Expression (5) to Expression (12) may be used as the matrix Fp. [Math. 5] Fp = β × e j 0 β × α × e j 0 β × α × e j 0 β × e jπ [Math. 6] Fp = 1 α 2 + 1 e j 0 α × e j 0 α × e j 0 e jπ [Math. 7] Fp = β × e j 0 β × α × e jπ β × α × e j 0 β × e j 0 [Math. 8] Fp = 1 α 2 + 1 e j 0 α × e jπ α × e j 0 e j 0 [Math. 9] Fp = β × α × e j 0 β × e jπ β × e j 0 β × α × e j 0 [Math. 10] Fp = 1 α 2 + 1 α × e j 0 e jπ e j 0 α × e j 0 [Math. 11] Fp = β × α × e j 0 β × e j 0 β × e j 0 β × α × e jπ [Math. 12] Fp = 1 α 2 + 1 α × e j 0 e j 0 e j 0 α × e jπ In Expression (5) to Expression (12), α may be a real number or an imaginary number. Also, β may be a real number or an imaginary number. However, α is not 0 (zero). Also, β is not 0 (zero).

[0068] Alternatively, any of the matrices expressed by the following Expression (13) to Expression (20) may be used as the matrix Fp. [Math. 13] Fp = β × cos θ β × sin θ β × sin θ − β × cos θ [Math. 14] Fp = cos θ sin θ sin θ − cos θ [Math. 15] Fp = β × cos θ − β × sin θ β × sin θ β × cos θ [Math. 16] Fp = cos θ − sin θ sin θ cos θ [Math. 17] Fp = β × sin θ − β × cos θ β × cos θ β × sin θ [Math. 18] Fp = sin θ − cos θ cos θ sin θ [Math. 19] Fp = β × sin θ β × cos θ β × cos θ − β × sin θ [Math. 20] Fp = sin θ cos θ cos θ − sin θ In Expression (13) to Expression (20), θ is a real number. In Expression (13), Expression (15), Expression (17), and Expression (19), β may be a real number or an imaginary number. However, β is not 0 (zero).

[0069] Alternatively, any of the matrices expressed by the following Expression (21) to Expression (32) may be used as the matrix Fp. [Math. 21] [Math. 22] [Math. 23] [Math. 24] [Math. 25] [Math. 26] [Math. 27] [Math. 28] [Math. 29] [Math. 30] [Math. 31] [Math. 32] Note that θ 11 (i), θ 21 (i), and λ(i) are functions of i (of a symbol number) and are real number values. For example, λ is a real number fixed value. Here, λ need not necessarily be 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). Also, β is not 0 (zero). In addition, θ 11 and θ 21 are real numbers.

[0070] Alternatively, any of the matrices expressed by the following Expression (33) to Expression (36) may be used as the matrix Fp. [Math. 33] Fp = 1 0 0 1 [Math. 34] Fp = β 0 0 β [Math. 35] Fp = 1 0 0 − 1 [Math. 36] Fp = β 0 0 − β In Expression (34) and Expression (36), β may be a real number or an imaginary number. However, β is not 0 (zero).

[0071] The individual embodiments can be carried out also by using a precoding matrix different from those expressed by Expressions (5) to (36) given above.

[0072] In a case where the precoding matrix Fp is expressed by Expression (33) or Expression (34), the weight combiner 303 in Fig. 3 does not perform signal processing on the mapped signals 301A and 301B and outputs the mapped signal 301A as the weighted signal 304A and the mapped signal 301B as the weighted and combined signal 304B. That is, the weight combiner 303 need not necessarily exist. In a case where the weight combiner 303 exists, control of whether or not to perform weight combining may be performed by the control signal 300.

[0073] The inserter 307A receives the weighted signal 304A, a pilot symbol signal (pa(t)) (351A), a preamble signal 352, a control information symbol signal 353, and the control signal 300. On the basis of information about a frame configuration included in the control signal 300, the inserter 307A outputs a baseband signal 308A that is based on the frame configuration to the multiplexing signal processor 104.

[0074] Likewise, the inserter 307B receives the phase-changed signal 306B, a pilot symbol signal (pb(t)) (351B), the preamble signal 352, the control information symbol signal 353, and the control signal 300. On the basis of information about a frame configuration included in the control signal 300, the inserter 307B outputs a baseband signal 308B that is based on the frame configuration to the phase changer 309B.

[0075] The generation of control information for generating the control information symbol signal 353 and the frame configuration in the transmission apparatus used in the inserter 307A and the inserter 307B will be described below.

[0076] The phase changer 309B receives the baseband signal 308B and the control signal 300. On the basis of the control signal 300, the phase changer 309B performs phase change on the baseband signal 308B, and outputs a phase-changed signal 310B to the multiplexing signal processor 104.

[0077] The baseband signal 308B is regarded as a function of the symbol number i and is represented by xp'(i). Accordingly, the phase-changed signal 310B (xp(i)) output from the phase changer 309B can be expressed by xp(i) = e j×ε(i)< ×xp'(i).

[0078] The operation of the phase changer 309B may be Cyclic Delay Diversity (CDD) (Cyclic Shift Diversity (CSD)) described in NPL 2 and NPL 3. A characteristic of the phase changer 309B is performing phase change on symbols existing in the frequency-axis direction. The phase changer 309B performs phase change on data symbols, pilot symbols, control information symbols, and the like.

[0079] Fig. 3 illustrates the signal processor 206 including the phase changer 309B, but the phase changer 309B need not necessarily be included in the signal processor 206. Alternatively, in a case where the phase changer 309B is included in the signal processor 206, whether or not the phase changer 309B operates may be switched. In a case where the phase changer 309B is not included in the signal processor 206 or in a case where the phase changer 309B does not operate, the inserter 307B outputs the baseband signal 308B to the multiplexing signal processor 104 in Fig. 1. In this way, in Fig. 3, in a case where the phase changer 309B does not exist or in a case where the phase changer 309B does not operate, the baseband signal 308B serves as a signal output to the multiplexing signal processor 104 instead of the phase-changed signal 310B. Hereinafter, a description will be given of, for the convenience of description, a case where the phase changer 309B does not operate.

[0080] In a case where weight combining (precoding) processing is performed by using the (precoding) matrix Fp expressed by Expression (33) or Expression (34), the weight combiner 303 does not perform signal processing for weight combining on the mapped signals 301A and 301B, but outputs the mapped signal 301A as the weighted signal 304A and outputs the mapped signal 301B as the weighted signal 304B.

[0081] In this case, the weight combiner 303 performs, on the basis of the control signal 300, control to switch between processing (i) of performing signal processing corresponding to weight combining to generate and output the weighted signals 304A and 304B, and processing (ii) of not performing signal processing for weight combining, but outputting the mapped signal 301A as the weighted signal 304A and outputting the mapped signal 301B as the weighted signal 304B.

[0082] In a case where weight combining (precoding) processing is performed by using only the (precoding) matrix Fp expressed by Expression (33) or Expression (34), the signal processor 206 in Fig. 2 need not necessary include the weight combiner 303.

[0083] A description has been given above of a case where the mapper 204 in Fig. 2 generates two sequences of signals in a case where multi-stream transmission is selected for the user #p. However, in a case where single-stream transmission is selected for the user #p, in Fig. 3, the weight combiner 303, the phase changer 306B, and the inserter 307B need not necessarily operate, and the user #p mapped signal 301A may be input to the inserter 307A without being weighted. Alternatively, in a case where single-stream transmission is selected, the user #p signal processor 102_p in Fig. 1 need not necessarily include the weight combiner 303, the phase changer 306B, and the inserter 307B among the elements in Fig. 3.

[0084] A description has been given above of a case where the mapper 204 in Fig. 2 generates two sequences of signals in a case where multi-stream transmission is selected for the user #p. However, the mapper 204 in Fig. 2 may generate three or more sequences of signals in a case where multi-stream transmission is selected for the user #p. In a case where the mapper 204 in Fig. 2 generates three or more sequences of signals, the weight combiner 303 in Fig. 3 performs, for example, weight combining by using a precoding matrix corresponding to the number of input signals and outputs three or more weighted signals. The number of signals input to the weight combiner 303 in Fig. 3 may be different from the number of signals output from the weight combiner 303. That is, the precoding matrix used in the weight combiner 303 need not necessarily be a square matrix.

[0085] In a case where the weight combiner 303 outputs three or more weighted signals, the signal processor 102_p may perform phase change on all or some of the three or more weighted signals. Alternatively, the signal processor 102_p need not necessarily perform phase change on all of the three or more weighted signals.

[0086] Fig. 4 is a diagram illustrating an example of the configuration of the signal processor 206 in Fig. 2, which is different from the example in Fig. 3. In Fig. 4, the elements similar to those in Fig. 3 are denoted by the same numerals. The description of the elements similar to those in Fig. 3 is omitted here.

[0087] The signal processor 206 in Fig. 4 has a configuration in which a coefficient multiplier 401A and a coefficient multiplier 401B are added to the signal processor 206 in Fig. 3.

[0088] The coefficient multiplier 401A receives the mapped signal 301A (sp1(i)) and the control signal 300. On the basis of the control signal 300, the coefficient multiplier 401A multiplies the mapped signal 301A (sp1(i)) by a coefficient, and outputs a coefficient-multiplied signal 402A to the weight combiner 303. When the coefficient is represented by up, the coefficient-multiplied signal 402A is expressed by up×sp1(i). Here, up may be a real number or a complex number. However, up is not 0 (zero). In a case where up = 1, the coefficient multiplier 401A does not multiply the mapped signal 301A (sp1(i)) by the coefficient, and outputs the mapped signal 301A (sp1(i)) as the coefficient-multiplied signal 402A.

[0089] Likewise, the coefficient multiplier 401B receives the mapped signal 301B (sp2(i)) and the control signal 300. On the basis of the control signal 300, the coefficient multiplier 401B multiplies the mapped signal 301B (sp2(i)) by a coefficient, and outputs a coefficient-multiplied signal 402B to the weight combiner 303. When the coefficient is represented by vp, the coefficient-multiplied signal 402B is expressed by vp×sp2(i). Here, vp may be a real number or a complex number. However, vp is not 0 (zero). In a case where vp = 1, the coefficient multiplier 401B does not multiply the mapped signal 301B (sp2(i)) by the coefficient, and outputs the mapped signal 301B (sp2(i)) as the coefficient-multiplied signal 402B.

[0090] In Fig. 4, the weighted signal 304A (zp1(i)) output from the weight combiner 303 and the phase-changed signal 306B (zp2(i)) output from the phase changer 305B are expressed by the following Expression (37) using the coefficient up of the coefficient multiplier 401A, the coefficient vp of the coefficient multiplier 401B, and Expression (3). [Math. 37] zp 1 i zp 2 i = 1 0 0 yp i Fp up 0 0 vp sp 1 i sp 2 i = 1 0 0 yp i a b c d up 0 0 vp sp 1 i sp 2 i = 1 0 0 e j × δp i a b c d up 0 0 vp sp 1 i sp 2 i Examples of the (precoding) matrix Fp are Expressions (5) to (36) as described above. An example of the phase change value yp(i) is expressed by Expression (2), but the (precoding) matrix Fp and the phase change value yp(i) are not limited thereto.

[0091] With use of Fig. 1 to Fig. 4 and Expression (1) to Expression (37) as an example, a description has been given of a method in which the user #p signal processor 102_p generates symbols (for example, zp1(i) and zp2(i)). The generated symbols may be arranged in the time-axis direction. In the case of using a multi-carrier scheme such as Orthogonal Frequency Division Multiplexing (OFDM), the generated symbols may be arranged in the frequency-axis direction or in the time and frequency directions. In addition, the generated symbols may be interleaved (i.e., the symbols may be sorted), and arranged in the time-axis direction, the frequency-axis direction, or the time-axis and frequency-axis directions.

[0092] The symbols are arranged by, for example, the error-correcting encoder 202 and / or the mapper 204 illustrated in Fig. 2 in the user #p signal processor 102_p.

[0093] A method for arranging the symbols will be described below.

[0094] The transmission apparatus illustrated in Fig. 1 transmits zp1(i) and zp2(i) having the same symbol number i by using identical times and identical frequencies (identical frequency bands).

[0095] The user #1 baseband signal 103_1_1 in Fig. 1 is zp1(i) when p = 1, and the user #1 baseband signal 103_1_2 is zp2(i) when p = 1. Likewise, the user #2 baseband signal 103_2_1 is zp1(i) when p = 2, and the user #2 baseband signal 103_2_2 is zp2(i) when p = 2. Likewise, the user #M baseband signal 103_M_1 is zp1(i) when p = M, and the user #M baseband signal 103_M_2 is zp2(i) when p = M.

[0096] The user #1 signal processor 102_1 generates the user #1 baseband signal 103_1_1 and the user #1 baseband signal 103_1_2 by using Expression (3) or Expression (37). Likewise, the user #2 signal processor 102_2 generates the user #2 baseband signal 103_2_1 and the user #2 baseband signal 103_2_2 by using Expression (3) or Expression (37). Likewise, the user #M signal processor 102_M generates the user #M baseband signal 103_M_1 and the user #M baseband signal 103_M_2.

[0097] At that time, in the case of generating the user #p baseband signal 103_p_1 and the user #p baseband signal 103_p_2 by applying precoding and phase change, the precoding matrix Fp made up of a, b, c, and d and / or the phase change value yp(i) in Expression (3) or Expression (37) are set in accordance with the value of p.

[0098] That is, the precoding matrix Fp and / or the phase change value yp(i) used in the user #p signal processor 102_p are set in accordance with the value of p, that is, for each user. The information for setting the precoding matrix Fp and / or the phase change value yp(i) is included in the control signal.

[0099] However, not all the user #1 signal processor 102_1 to the user #M signal processor 102_M in Fig. 1 may apply precoding and phase change. For example, a signal processor that does not perform phase change may exist among the user #1 signal processor 102_1 to the user #M signal processor 102_M. Also, a signal processor that generates one baseband signal (one stream of a baseband signal) may exist among the user #1 signal processor 102_1 to the user #M signal processor 102_M.

[0100] As described above, in a case where precoding and phase change are performed in the user #1 signal processor 102_1 to the user #M signal processor 102_M in Fig. 1 as described in the present embodiment, a possibility of being able to avoid falling into a steady reception state in an environment in which direct waves are dominant is increased. Accordingly, the data reception quality at a terminal can be improved. In addition, by transmitting modulated signals of multiple users as in Fig. 1, the data transmission efficiency of the transmission apparatus in Fig. 1 increases.

[0101] In a case where the control signal 300 includes information indicating "the phase changer 305B does not perform phase change", the phase changer 305B does not perform phase change. That is, the phase changer 305B may omit phase change for the weighted signal 304B input thereto and may output the weighted signal 304B as 306B.<Example of Multiplexing Signal Processing in Multiplexing Signal Processor 104>

[0102] A detailed description will be given of the multiplexing signal processing (weight combining processing) in the multiplexing signal processor 104 in Fig. 1.

[0103] It is assumed that the user #p first baseband signal 103_p_1 and the user #p second baseband signal 103_p_2 output from the user #p signal processor 102_p (p is an integer from 1 to M) in Fig. 1 are respectively represented by zp1(i) and zp2(i) on the basis of Expression (3). It is assumed that i is a symbol number and is, for example, an integer equal to or greater than 0. At this time, it is assumed that signals b{2p-1}(i) and b{2p}(i) are expressed by the following Expressions (38) and (39). [Math. 38] b 2 p − 1 i = zp 1 i [Math. 39] b 2 p i = zp 2 i

[0104] For example, the user #1 first baseband signal 103_1_1 and the user #1 second baseband signal 103_1_2 are respectively represented by b{1}(i) and b{2}(i). That is, in a case where each of the user #1 signal processor 102_1 to the user #M signal processor 102_M outputs two signals, the output signals are represented by b{1}(i) to b{2M}(i).

[0105] In the case of transmitting a single stream (single modulated signal), either zp1(i) or zp2(i) may be zero.

[0106] The multiplexed signal $1 baseband signal 105_1 to the multiplexed signal $N baseband signal 105_N, which are outputs of the multiplexing signal processor 104, are respectively represented by v1(i) to vN(i). That is, the multiplexed signal $n baseband signal 105_n is represented by vn(i) (n is an integer from 1 to N). At this time, vn(i) can be expressed by the following Expression (40). [Math. 40] vn i = ∑ k = 1 2 M Ω n k × b k i At this time, Ω{n}{k} is a weighted coefficient of multiplexing and can be defined as a complex number. Thus, Ω{n}{k} may be a real number. In addition, Ω{n}{k} is decided by feedback information of each terminal.

[0107] In the present embodiment, a description is given of, as an example, a case where the user #p signal processor 102_p in Fig. 1 outputs one or two modulated signals, but the embodiment is not limited thereto. The user #p signal processor 102_p may output three or more modulated signals. In this case, the processing of the multiplexing signal processor 104 needs to be expressed by an expression different from Expression (40).<Example of Configuration of Radio Section>

[0108] The radio section $1 (106_1) to the radio section $N (106_N) in Fig. 1 each perform processing such as frequency conversion and amplification on a signal input thereto and generate a transmission signal, as described above. At this time, in the radio section $1 (106_1) to the radio section $N (106_N), either a single-carrier scheme or a multi-carrier scheme such as the Orthogonal Frequency Division Multiplexing (OFDM) scheme may be used. Hereinafter, a description will be given of, as an example, the radio section $n (106_n) that uses the OFDM scheme.

[0109] Fig. 5 is a diagram illustrating an example of the configuration of the radio section $n (106_n) that uses the OFDM scheme. The radio section $n (106_n) includes a serial-parallel converter 502, an inverse Fourier transform section 504, and a processor 506.

[0110] The serial-parallel converter 502 receives a signal 501 and a control signal 500. On the basis of the control signal 500, the serial-parallel converter 502 performs serial-parallel conversion on the signal 501 input thereto, and outputs a serial-parallel-converted signal 503 to the inverse Fourier transform section 504. The signal 501 corresponds to the multiplexed signal $n baseband signal 105_n in Fig. 1, and the control signal 500 corresponds to the control signal 100 in Fig. 1.

[0111] The inverse Fourier transform section 504 receives the serial-parallel-converted signal 503 and the control signal 500. On the basis of the control signal 500, the inverse Fourier transform section 504 performs inverse Fourier transform (for example, inverse fast Fourier transform (IFFT)) and outputs an inverse-Fourier-transformed signal 505 to the processor 506.

[0112] The processor 506 receives the inverse-Fourier-transformed signal 505 and the control signal 500. On the basis of the control signal 500, the processor 506 performs processing such as frequency conversion and amplification, and outputs a modulated signal 507 to the antenna section $n (108_n). The modulated signal 507 output from the processor 506 corresponds to the transmission signal 107_n in Fig. 1.<Example of Configuration of Antenna Section>

[0113] Fig. 6 is a diagram illustrating an example of the configuration of each of the antenna sections (the antenna section $1 (108_1) to the antenna section $N (108_N)) in Fig. 1. The configuration in Fig. 6 is an example in which the antenna section $1 (108_1) to the antenna section $N (108_N) are each constituted by four antennas. The antenna section includes a distributor 902, multipliers 904_1 to 904_4, and antennas 906_1 to 906_4.

[0114] The distributor 902 receives a transmission signal 901. The distributor 902 distributes the transmission signal 901 and outputs transmission signals 903_1, 903_2, 903_3, and 903_4 to the corresponding multipliers (the multiplier 904_1 to the multiplier 904_4).

[0115] When the antenna section $1 (108_1) in Fig. 1 has the configuration in Fig. 6, the transmission signal 901 corresponds to the transmission signal 107_1 in Fig. 1. When the antenna section $2 (108_2) in Fig. 1 has the configuration in Fig. 6, the transmission signal 901 corresponds to the transmission signal 107_2 in Fig. 1. When the antenna section $N (108_N) in Fig. 1 has the configuration in Fig. 6, the transmission signal 901 corresponds to the transmission signal 107_N in Fig. 1.

[0116] The multiplier 904_1 receives the transmission signal 903_1 and a control signal 900. On the basis of information about a multiplication coefficient included in the control signal 900, the multiplier 904_1 multiplies the transmission signal 903_1 by the multiplication coefficient, and outputs a multiplied signal 905_1 to the antenna 906_1. The multiplied signal 905_1 is output as a radio wave from the antenna 906_1.

[0117] When the transmission signal 903_1 is represented by Tx1(t) (t is time) and the multiplication coefficient is represented by W1, the multiplied signal 905_1 is expressed by Tx1(t)×W1. Here, W1 can be defined as a complex number and thus may be a real number.

[0118] The multiplier 904_2 receives the transmission signal 903_2 and the control signal 900. On the basis of information about a multiplication coefficient included in the control signal 900, the multiplier 904_2 multiplies the transmission signal 903_2 by the multiplication coefficient, and outputs a multiplied signal 905_2 to the antenna 906_2. The multiplied signal 905_2 is output as a radio wave from the antenna 906_2.

[0119] When the transmission signal 903_2 is represented by Tx2(t) and the multiplication coefficient is represented by W2, the multiplied signal 905_2 is expressed by Tx2(t)×W2. Here, W2 can be defined as a complex number and thus may be a real number.

[0120] The multiplier 904_3 receives the transmission signal 903_3 and the control signal 900. On the basis of information about a multiplication coefficient included in the control signal 900, the multiplier 904_3 multiplies the transmission signal 903_3 by the multiplication coefficient, and outputs a multiplied signal 905_3 to the antenna 906_3. The multiplied signal 905_3 is output as a radio wave from the antenna 906_3.

[0121] When the transmission signal 903_3 is represented by Tx3(t) and the multiplication coefficient is represented by W3, the multiplied signal 905_3 is expressed by Tx3(t)×W3. Here, W3 can be defined as a complex number and thus may be a real number.

[0122] The multiplier 904_4 receives the transmission signal 903_4 and the control signal 900. On the basis of information about a multiplication coefficient included in the control signal 900, the multiplier 904_4 multiplies the transmission signal 903_4 by the multiplication coefficient, and outputs a multiplied signal 905_4 to the antenna 906_4. The multiplied signal 905_4 is output as a radio wave from the antenna 906_4.

[0123] When the transmission signal 903_4 is represented by Tx4(t) and the multiplication coefficient is represented by W4, the multiplied signal 905_4 is expressed by Tx4(t)×W4. Here, W4 can be defined as a complex number and thus may be a real number.

[0124] Here, "the absolute value of W1, the absolute value of W2, the absolute value of W3, and the absolute value of W4 may be equal". This corresponds to a state where phase change has been performed. Obviously, the absolute value of W1, the absolute value of W2, the absolute value of W3, and the absolute value of W4 may be unequal.

[0125] In Fig. 6, a description is given of an example in which each antenna section is constituted by four antennas (and four multipliers). However, the number of antennas is not limited four, and it is sufficient that each antenna section be constituted by one or more antennas.

[0126] In addition, the antenna section $1 (108_1) to the antenna section $N (108_N) each need not necessarily have the configuration as in Fig. 6, and the antenna section need not necessarily receive the control signal 100, as described above. For example, each of the antenna section $1 (108_1) to the antenna section $N (108_N) in Fig. 1 may be constituted by one antenna or multiple antennas.<Generation of Control Information>

[0127] Fig. 7 is a diagram illustrating an example of the configuration of a portion related to control information generation for generating the control information symbol signal 353 in Figs. 3 and 4.

[0128] A control information mapper 802 receives control information-related data 801 and a control signal 800. The control information mapper 802 performs mapping on the control information-related data 801 by using a modulation scheme that is based on the control signal 800, and outputs a control information mapped signal 803. The control information mapped signal 803 corresponds to the control information symbol signal 353 in Figs. 3 and 4.<First Example of Frame Configuration in Transmission apparatus>

[0129] Next, a frame configuration in the transmission apparatus will be described. The frame configuration shows the arrangement of data symbols, pilot symbols, and other symbols to be transmitted. Information about the frame configuration is included in the control signal 300 (see Figs. 3 and 4). The inserter 307A and the inserter 307B illustrated in Figs. 3 and 4 respectively generate the baseband signal 308A and the baseband signal 308B that are based on the frame configuration.

[0130] Hereinafter, an example is given in which a multi-carrier transmission scheme such as OFDM is used, the inserter 307A in the user #p signal processor 102_p outputs the user #p first baseband signal 103_p_1 in Fig. 1 as the baseband signal 308A, and the inserter 307B outputs the user #p second baseband signal 103_p_2 in Fig. 1 as the baseband signal 308B. The frame configurations of the user #p first baseband signal 103_p_1 and the user #p second baseband signal 103_p_2 in this case will be described as an example.

[0131] Fig. 8 is a diagram illustrating an example of the frame configuration of the user #p first baseband signal 103_p_1. In Fig. 8, the horizontal axis indicates frequency (carrier), and the vertical axis indicates time. Since a multi-carrier transmission scheme such as OFDM is used, symbols exist in the carrier direction. Fig. 8 illustrates, as an example, symbols from carrier 1 to carrier 36. In addition, Fig. 8 illustrates symbols from time 1 to time 11.

[0132] In Fig. 8, 601 denotes a pilot symbol (the pilot symbol signal 351A (corresponding to pa(t)) in Figs. 3 and 4), 602 denotes a data symbol, and 603 denotes an other symbol. At this time, the pilot symbols are Phase Shift Keying (PSK) symbols, for example, and are symbols used by a reception apparatus that receives this frame to perform channel estimation (estimation of propagation path variation) and estimation of frequency offset / phase variation. For example, the transmission apparatus in Fig. 1 and the reception apparatus that receives a signal having the frame configuration in Fig. 8 may preferably share a method for transmitting the pilot symbols.

[0133] Here, the user #p mapped signal 205_1 is called "stream #1", and the user #p mapped signal 205_2 is called "stream #2". The same applies to the description given below.

[0134] The data symbols 602 are symbols corresponding to the data symbols included in the baseband signal 207_A generated in Fig. 2. Thus, the data symbols 602 are any of "symbols including both the symbols of "stream #1" and the symbols of "stream #2"", "the symbols of "stream #1"", and "the symbols of "stream #2"". This is decided by the configuration of the precoding matrix used by the weight combiner 303 in Fig. 3. That is, the data symbols 602 correspond to the weighted signal 304A (zp1(i)).

[0135] The other symbols 603 are symbols corresponding to the preamble signal 352 and the control information symbol signal 353 in Figs. 3 and 4. However, the other symbols may include symbols other than a preamble and control information symbols. At this time, the preamble may transmit data (for control), and are made up of symbols for signal detection, symbols for performing frequency synchronization / time synchronization, symbols for channel estimation (symbols for estimating propagation path variation), and so forth. The control information symbols are symbols including control information that is used by the reception apparatus that has received the frame in Fig. 8 to demodulate and decode the data symbols.

[0136] For example, carrier 1 to carrier 36 from time 1 to time 4 in Fig. 8 correspond to the other symbols 603. Carrier 1 to carrier 11 at time 5 correspond to the data symbols 602. In the following, carrier 12 at time 5 corresponds to the pilot symbol 601, carrier 13 to carrier 23 at time 5 correspond to the data symbols 602, carrier 24 at time 5 corresponds to the pilot symbol 601, carrier 1 and carrier 2 at time 6 correspond to the data symbols 602, carrier 3 at time 6 corresponds to the pilot symbol 601, carrier 30 at time 11 corresponds to the pilot symbol 601, and carrier 31 to carrier 36 at time 11 correspond to the data symbols 602.

[0137] Fig. 9 is a diagram illustrating an example of the frame configuration of the user #p second baseband signal 103_p_2. In Fig. 9, the horizontal axis indicates frequency (carrier), and the vertical axis indicates time. Since a multi-carrier transmission scheme such as OFDM is used, symbols exist in the carrier direction. Fig. 9 illustrates, as an example, symbols from carrier 1 to carrier 36. In addition, Fig. 9 illustrates symbols from time 1 to time 11.

[0138] In Fig. 9, 701 denotes a pilot symbol (the pilot symbol signal 351B (corresponding to pb(t)) in Figs. 3 and 4), 702 denotes a data symbol, and 703 denotes an other symbol. At this time, the pilot symbols are PSK symbols, for example, and are symbols used by a reception apparatus that receives this frame to perform channel estimation (estimation of propagation path variation) and estimation of frequency offset / phase variation. For example, the transmission apparatus in Fig. 1 and the reception apparatus that receives a signal having the frame configuration in Fig. 9 may preferably share a method for transmitting the pilot symbols.

[0139] The data symbols 702 are symbols corresponding to the data symbols included in the baseband signal 207_B generated in Fig. 2. Thus, the data symbols 702 are any of "symbols including both the symbols of "stream #1" and the symbols of "stream #2"", "the symbols of "stream #1"", and "the symbols of "stream #2"". Which symbols among the above three are to be used is decided by the configuration of the precoding matrix used by the weight combiner 303 in Fig. 3. That is, the data symbols 702 correspond to the phase-changed signal 306B (zp2(i)).

[0140] The other symbols 703 are symbols corresponding to the preamble signal 352 and the control information symbol signal 353 in Figs. 3 and 4. However, the other symbols may include symbols other than a preamble and control information symbols. At this time, the preamble may transmit data (for control), and are made up of symbols for signal detection, symbols for performing frequency synchronization / time synchronization, symbols for channel estimation (symbols for estimating propagation path variation), and so forth. The control information symbols are symbols including control information that is used by the reception apparatus that has received the frame in Fig. 9 to demodulate and decode the data symbols.

[0141] For example, carrier 1 to carrier 36 from time 1 to time 4 in Fig. 9 correspond to the other symbols 703. Carrier 1 to carrier 11 at time 5 correspond to the data symbols 702. In the following, carrier 12 at time 5 corresponds to the pilot symbol 701, carrier 13 to carrier 23 at time 5 correspond to the data symbols 702, carrier 24 at time 5 corresponds to the pilot symbol 701, carrier 1 and carrier 2 at time 6 correspond to the data symbols 702, carrier 3 at time 6 corresponds to the pilot symbol 701, carrier 30 at time 11 corresponds to the pilot symbol 701, and carrier 31 to carrier 36 at time 11 correspond to the data symbols 702.

[0142] When a symbol exists at carrier A and time B in Fig. 8 and a symbol exists at carrier A and time B in Fig. 9, the symbol at carrier A and time B in Fig. 8 and the symbol at carrier A and time B in Fig. 9 are transmitted at identical times and identical frequencies. The frame configuration is not limited to those in Figs. 8 and 9. The frame configurations in Figs. 8 and 9 are merely examples.

[0143] The other symbols 603 and 703 in Figs. 8 and 9 are symbols corresponding to "the preamble signal 352 and the control symbol 353 in Figs. 3 and 4". Thus, in a case where the other symbols 603 in Fig. 8 and the other symbols 703 in Fig. 9 at the identical times and identical frequencies (identical carriers) are transmitting control information, identical data (identical control information) is being transmitted.

[0144] The reception apparatus expects to simultaneously receive the frame in Fig. 8 and the frame in Fig. 9. However, the reception apparatus is able to obtain data transmitted by the transmission apparatus even if the reception apparatus receives only the frame in Fig. 8 or only the frame in Fig. 9.

[0145] In a case where the user #1 signal processor 102_1 in Fig. 1 outputs the first baseband signal 103_1_1 and the second baseband signal 103_1_2, the first baseband signal 103_1_1 and the second baseband signal 103_1_2 respectively have the frame configurations in Figs. 8 and 9. Likewise, in a case where the user #2 signal processor 102_2 in Fig. 1 outputs the first baseband signal 103_2_1 and the second baseband signal 103_2_2, the first baseband signal 103_2_1 and the second baseband signal 103_2_2 respectively have the frame configurations in Figs. 8 and 9. Likewise, in a case where the user #M signal processor 102_M in Fig. 1 outputs the first baseband signal 103_M_1 and the second baseband signal 103_M_2, the first baseband signal 103_M_1 and the second baseband signal 103_M_2 respectively have the frame configurations in Figs. 8 and 9.<Second Example of Frame Configuration in Transmission apparatus>

[0146] In Figs. 8 and 9, a description has been given of a frame configuration in a case where a multi-carrier transmission scheme such as OFDM is used. Now, a description will be given of a frame configuration in the transmission apparatus in a case where a single-carrier scheme is used.

[0147] Fig. 10 is a diagram illustrating another example of the frame configuration of the user #p first baseband signal 103_p_1. In Fig. 10, the horizontal axis indicates time. The difference between Figs. 10 and 8 is that the frame configuration in Fig. 10 is an example of the frame configuration for a single-carrier scheme and symbols exist in the time direction. In addition, Fig. 10 illustrates symbols from time t1 to t22.

[0148] A preamble 1001 in Fig. 10 corresponds to the preamble signal 352 in Figs. 3 and 4. At this time, the preamble may transmit data (for control), and may be made up of symbols for signal detection, symbols for performing frequency synchronization / time synchronization, symbols for performing channel estimation (symbols for estimating propagation path variation), and so forth.

[0149] A control information symbol 1002 in Fig. 10 is a symbol corresponding to the control information symbol signal 353 in Figs. 3 and 4, and is a symbol including control information that is used by the reception apparatus that has received a signal having the frame configuration in Fig. 10 to demodulate and decode data symbols.

[0150] A pilot symbol 1004 in Fig. 10 is a symbol corresponding to the pilot signal 351A (pa(t)) in Figs. 3 and 4. The pilot symbol 1004 is a PSK symbol, for example, and is a symbol that is used by the reception apparatus that receives this frame to perform channel estimation (estimation of propagation path variation) and estimation of frequency offset / estimation of phase variation. For example, the transmission apparatus in Fig. 1 and the reception apparatus that receives a signal having the frame configuration in Fig. 10 may preferably share a method for transmitting the pilot symbol.

[0151] In Fig. 10, 1003 denotes data symbols for transmitting data.

[0152] The user #p mapped signal 205_1 is called "stream #1", and the user #p mapped signal 205_2 is called "stream #2".

[0153] The data symbols 1003 are symbols corresponding to the data symbols included in the baseband signal 206_A generated in Fig. 2. Thus, the data symbols 1003 are any symbols among three candidates: "symbols including both the symbols of "stream #1" and the symbols of "stream #2"", "the symbols of "stream #1"", and "the symbols of "stream #2"". Which symbols among the above three are to be used is decided by the configuration of the precoding matrix used by the weight combiner 303 in Fig. 3. That is, the data symbols 1003 correspond to the weighted signal 304A (zp1(i)).

[0154] For example, it is assumed that the transmission apparatus transmits the preamble 1001 at time t1 in Fig. 10, transmits the control information symbol 1002 at time t2, transmits the data symbols 1003 from time t3 to t11, transmits the pilot symbol 1004 at time t12, transmits the data symbols 1003 from time t13 to t21, and transmits the pilot symbol 1004 at time t22.

[0155] Although not illustrated in Fig. 10, the frame may include symbols other than the preamble, the control information symbol, the data symbols, and the pilot symbols. In addition, the frame need not necessarily include all of the preamble, the control information symbol, and the pilot symbols.

[0156] Fig. 11 is a diagram illustrating another example of the frame configuration of the user #p second baseband signal 103_p_2. In Fig. 11, the horizontal axis indicates time. The difference between Figs. 11 and 9 is that the frame configuration in Fig. 11 is an example of the frame configuration for a single-carrier scheme and symbols exist in the time direction. In addition, Fig. 11 illustrates symbols from time t1 to t22.

[0157] A preamble 1101 in Fig. 11 corresponds to the preamble signal 352 in Figs. 3 and 4. At this time, the preamble may transmit data (for control), and may be made up of symbols for signal detection, symbols for performing frequency synchronization / time synchronization, symbols for performing channel estimation (symbols for estimating propagation path variation), and so forth.

[0158] A control information symbol 1102 in Fig. 11 is a symbol corresponding to the control information symbol signal 353 in Figs. 3 and 4, and is a symbol including control information that is used by the reception apparatus that has received a signal having the frame configuration in Fig. 11 to demodulate and decode data symbols.

[0159] A pilot symbol 1104 in Fig. 11 is a symbol corresponding to the pilot signal 351B (pb(t)) in Figs. 3 and 4. The pilot symbol 1104 is a PSK symbol, for example, and is a symbol that is used by the reception apparatus that receives this frame to perform channel estimation (estimation of propagation path variation) and estimation of frequency offset / estimation of phase variation. For example, the transmission apparatus in Fig. 1 and the reception apparatus that receives a signal having the frame configuration in Fig. 11 may preferably share a method for transmitting the pilot symbol.

[0160] In Fig. 11, 1103 denotes data symbols for transmitting data.

[0161] The user #p mapped signal 205_1 is called "stream #1", and the user #p mapped signal 205_2 is called "stream #2"

[0162] The data symbols 1103 are symbols corresponding to the data symbols included in the baseband signal 206_B generated in Fig. 2. Thus, the data symbols 1103 are any symbols among three candidates: "symbols including both the symbols of "stream #1" and the symbols of "stream #2"", "the symbols of "stream #1"", and "the symbols of "stream #2"". Which symbols among the above three are to be used is decided by the configuration of the precoding matrix used by the weight combiner 303 in Fig. 3. That is, the data symbols 1103 correspond to the phase-changed signal 306B (zp2(i)).

[0163] For example, it is assumed that the transmission apparatus transmits the preamble 1101 at time t1 in Fig. 11, transmits the control information symbol 1102 at time t2, transmits the data symbols 1103 from time t3 to t11, transmits the pilot symbol 1104 at time t12, transmits the data symbols 1103 from time t13 to t21, and transmits the pilot symbol 1104 at time t22.

[0164] Although not illustrated in Fig. 11, the frame may include symbols other than the preamble, the control information symbol, the data symbols, and the pilot symbols. In addition, the frame need not necessarily include all of the preamble, the control information symbol, and the pilot symbols.

[0165] When a symbol exists at time tz in Fig. 10 and a symbol exists at time tz in Fig. 10 (z is an integer equal to or greater than 1), the symbol at time tz in Fig. 10 and the symbol at time tz in Fig. 11 are transmitted at identical times and identical frequencies. For example, the data symbol at time t3 in Fig. 10 and the data symbol at time t3 in Fig. 11 are transmitted at identical times and identical frequencies. The frame configuration is not limited to those in Figs. 10 and 11. The frame configurations in Figs. 10 and 11 are merely examples.

[0166] The preamble and the control information symbol in Figs. 10 and 11 may transmit identical data (identical control information).

[0167] The reception apparatus expects to simultaneously receive the frame in Fig. 10 and the frame in Fig. 11. However, the reception apparatus is able to obtain data transmitted by the transmission apparatus even if the reception apparatus receives only the frame in Fig. 10 or only the frame in Fig. 11.

[0168] In a case where the user #1 signal processor 102_1 in Fig. 1 outputs the first baseband signal 103_1_1 and the second baseband signal 103_1_2, the first baseband signal 103_1_1 and the second baseband signal 103_1_2 respectively have the frame configurations in Figs. 10 and 11. Likewise, in a case where the user #2 signal processor 102_2 in Fig. 1 outputs the first baseband signal 103_2_1 and the second baseband signal 103_2_2, the first baseband signal 103_2_1 and the second baseband signal 103_2_2 respectively have the frame configurations in Figs. 10 and 11. Likewise, in a case where the user #M signal processor 102_M in Fig. 1 outputs the first baseband signal 103_M_1 and the second baseband signal 103_M_2, the first baseband signal 103_M_1 and the second baseband signal 103_M_2 respectively have the frame configurations in Figs. 10 and 11.<Method for Arranging Symbols>

[0169] Next, a description will be given of a method for arranging symbols in the present embodiment. Symbols are sorted with respect to the frequency axis and / or the time axis by an interleaver. For example, symbols are arranged by the error-correcting encoder 202 and / or the mapper 204 illustrated in Fig. 2 in the user #p signal processor 102_p.

[0170] Fig. 12 is a diagram illustrating an example of a method for arranging symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) with respect to the time axis.

[0171] In Fig. 12, a symbol is denoted by zpq(0). At this time, q is 1 or 2. Thus, zpq(0) in Fig. 12 represents "in zp1(i) and zp2(i), zp1(0) and zp2(0) when the symbol number i = 0". Likewise, zpq(1) represents "in zp1(i) and zp2(i), zp1(1) and zp2(1) when the symbol number i = 1". That is, zpq(X) represents "in zp1(i) and zp2(i), zp1(X) and zp2(X) when the symbol number i = X". The same applies to Figs. 13, 14, and 15.

[0172] In the example in Fig. 12, the symbol zpq(0) with the symbol number i = 0 is arranged at time 0, the symbol zpq(1) with the symbol number i = 1 is arranged at time 1, the symbol zpq(2) with the symbol number i = 2 is arranged at time 2, and the symbol zpq(3) with the symbol number i = 3 is arranged at time 3. In this way, symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) are arranged with respect to the time axis. However, Fig. 12 is an example, and the relationship between the symbol number and time is not limited thereto.

[0173] Fig. 13 is a diagram illustrating an example of a method for arranging symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) with respect to the frequency axis.

[0174] In the example in Fig. 13, the symbol zpq(0) with the symbol number i = 0 is arranged at carrier 0, the symbol zpq(1) with the symbol number i = 1 is arranged at carrier 1, the symbol zpq(2) with the symbol number i = 2 is arranged at carrier 2, and the symbol zpq(3) with the symbol number i = 3 is arranged at carrier 3. In this way, symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) are arranged with respect to the frequency axis. However, Fig. 13 is an example, and the relationship between the symbol number and frequency is not limited thereto.

[0175] Fig. 14 is a diagram illustrating an example of the arrangement of symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) with respect to the time and frequency axes.

[0176] In the example in Fig. 14, the symbol zpq(0) with the symbol number i = 0 is arranged at time 0 and carrier 0, the symbol zpq(1) with the symbol number i = 1 is arranged at time 0 and carrier 1, the symbol zpq(2) with the symbol number i = 2 is arranged at time 1 and carrier 0, and the symbol zpq(3) with the symbol number i = 3 is arranged at time 1 and carrier 1. In this way, symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) are arranged with respect to the time and frequency axes. However, Fig. 14 is an example, and the relationship between the symbol number and time / frequency is not limited thereto.

[0177] Fig. 15 is a diagram illustrating an example of the arrangement of symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) with respect to the time axis.

[0178] In the example in Fig. 15, the symbol zpq(0) with the symbol number i = 0 is arranged at time 0, the symbol zpq(1) with the symbol number i = 1 is arranged at time 16, the symbol zpq(2) with the symbol number i = 2 is arranged at time 12, and the symbol zpq(3) with the symbol number i = 3 is arranged at time 5. In this way, symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) in Fig. 3 are arranged with respect to the time axis. That is, in the example in Fig. 15, the symbols are sorted in the time-axis direction. However, Fig. 15 is an example, and the relationship between the symbol number and time is not limited thereto.

[0179] In Fig. 15, each symbol is denoted by zpq(i), which may be a symbol generated by multiplexing signals directed to multiple users by the multiplexing signal processor 104 in Fig. 1. In addition, the example in Fig. 15 may be the arrangement of symbols in a case where each of the radio section $1 (106_1) to the radio section $N (106_N) in Fig. 1 includes an interleaver (a section that sorts symbols) and each interleaver sorts symbols. The position where interleaving is performed is not limited to the user signal processor or the radio section.

[0180] Fig. 16 is a diagram illustrating an example of the arrangement of symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) with respect to the frequency axis.

[0181] In the example in Fig. 16, the symbol zpq(0) with the symbol number i = 0 is arranged at carrier 0, the symbol zpq(1) with the symbol number i = 1 is arranged at carrier 16, the symbol zpq(2) with the symbol number i = 2 is arranged at carrier 12, and the symbol zpq(3) with the symbol number i = 3 is arranged at carrier 5. In this way, symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) in Fig. 3 are arranged with respect to the frequency axis. However, Fig. 16 is an example, and the relationship between the symbol number and frequency is not limited thereto.

[0182] In Fig. 16, each symbol is denoted by zpq(i), which may be a symbol generated by multiplexing signals directed to multiple users by the multiplexing signal processor 104 in Fig. 1. In addition, the example in Fig. 16 may be the arrangement of symbols in a case where each of the radio section $1 (106_1) to the radio section $N (106_N) in Fig. 1 includes an interleaver (a section that sorts symbols) and each interleaver sorts symbols. The position where interleaving is performed is not limited to the user signal processor or the radio section.

[0183] Fig. 17 is a diagram illustrating an example of the arrangement of symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) with respect to the time and frequency axes.

[0184] In the example in Fig. 17, the symbol zpq(0) with the symbol number i = 0 is arranged at time 1 and carrier 1, the symbol zpq(1) with the symbol number i = 1 is arranged at time 3 and carrier 3, the symbol zpq(2) with the symbol number i = 2 is arranged at time 1 and carrier 0, and the symbol zpq(3) with the symbol number i = 3 is arranged at time 1 and carrier 3. In this way, symbols of the weighted signal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) in Fig. 3 are arranged with respect to the time and frequency axes. However, Fig. 17 is an example, and the relationship between the symbol number and time / frequency is not limited thereto.

[0185] In Fig. 17, each symbol is denoted by zpq(i), which may be a symbol generated by multiplexing signals directed to multiple users by the multiplexing signal processor 104 in Fig. 1. In addition, the example in Fig. 17 may be the arrangement of symbols in a case where each of the radio section $1 (106_1) to the radio section $N (106_N) in Fig. 1 includes an interleaver (a section that sorts symbols) and each interleaver sorts symbols. The position where interleaving is performed is not limited to the user signal processor or the radio section.

[0186] According to the description given above, the arrangement of symbols is performed by, for example, the error-correcting encoder 202 and / or the mapper 204 illustrated in Fig. 2 in the user #p signal processor 102_p, but the embodiment is not limited thereto. As described above, each of the radio section $1 (106_1) to the radio section $N (106_N) in Fig. 1 may include an interleaver (a section that sorts symbols) and each interleaver may sort symbols. Alternatively, the multiplexing signal processor 104 may include an interleaver, and the interleaver may perform the arrangement of symbols illustrated in Figs. 12 to 17. Hereinafter, a description will be given of the multiplexing signal processor 104 that includes an interleaver with reference to Fig. 18.<Another Example of Configuration of Multiplexing Signal Processor>

[0187] Fig. 18 is a diagram illustrating the configuration of the multiplexing signal processor 104 in Fig. 1 that includes an interleaver (a section that sorts symbols).

[0188] A user #1 interleaver (sorter) 1802_1 receives processed signals 1801_1_1 and 1801_1_2 and a control signal 1800. The processed signals 1801_1_1 and 1801_1_2 respectively correspond to the user#1 first baseband signal 103_1_1 and the user #1 second baseband signal 103_1_2103_1_2 in Fig. 1. The control signal 1800 corresponds to the control signal 100 in Fig. 1.

[0189] In accordance with the control signal 1800, the user #1 interleaver (sorter) 1802_1 sorts symbols as in Figs. 12 to 17, and outputs user#1 sorted signals 1803_1 and 1803_2, for example.

[0190] The multiplexing signal processor 104 also includes a user #2 interleaver to a user #M interleaver. The user #2 interleaver to the user #M interleaver each have a function similar to that of the user #1 interleaver 1802_1.

[0191] A signal processor 1804 receives the control signal 1800, the user #1 sorted signals 1803_1 and 1803_2, and so forth. The signal processor 1804 also receives sorted signals for other users. In accordance with the control signal 1800, the signal processor 1804 performs signal processing such as the weight combining described above on the sorted signals and outputs a multiplexed signal $1 baseband signal 1805_1 to a multiplexed signal $N baseband signal 1805_N. The multiplexed signal $1 baseband signal 1805_1 to the multiplexed signal $N baseband signal 1805_N respectively correspond to the multiplexed signal $1 baseband signal 105_1 to the multiplexed signal $N baseband signal 105_N in Fig. 1.

[0192] An example of the transmission apparatus according to the present embodiment has been described above. Next, an example of the configuration of the reception apparatus according to the present embodiment will be described.<Example of Configuration of Reception Apparatus>

[0193] Fig. 19 is a diagram illustrating an example of the configuration of the reception apparatus according to the present embodiment. The reception apparatus in Fig. 19 is a reception apparatus of a terminal corresponding to a user #p among a user #1 to a user #M that receive modulated signals when the transmission apparatus in Fig. 1 transmits, for example, transmission signals having the frame configurations in Figs. 8 and 9 or transmission signals having the frame configurations in Figs. 10 and 11.

[0194] A radio section 1903X receives a reception signal 1902X received by an antenna section #X (1901X). The radio section 1903X performs reception processing such as frequency conversion and Fourier transform, and outputs a baseband signal 1904X to a modulated signal u1 channel estimator 1905_1 and a modulated signal u2 channel estimator 1905_2.

[0195] Likewise, a radio section 1903Y receives a reception signal 1902Y received by an antenna section #Y (1901Y). The radio section 1903Y performs reception processing such as frequency conversion and Fourier transform, and outputs a baseband signal 1904Y.

[0196] Fig. 19 illustrates a configuration in which a control signal 1910 is input to the antenna section #X (1901X) and the antenna section #Y (1901Y), but the control signal 1910 need not necessarily be input thereto. The configuration of an antenna section in a case where the control signal 1910 exists as input will be described below.

[0197] The modulated signal u1 channel estimator 1905_1 and the modulated signal u2 channel estimator 1905_2 perform channel estimation on the basis of the baseband signal 1904X. A modulated signal u1 channel estimator 1907_1 and a modulated signal u2 channel estimator 1907_2 perform channel estimation on the basis of the baseband signal 1904Y. The channel estimation will be described with reference to Fig. 20.

[0198] Fig. 20 is a diagram illustrating the relationship between the transmission apparatus and the reception apparatus. Antennas 2001_1 and 2001_2 in Fig. 20 are transmission antennas. The antenna 2001_1 in Fig. 20 corresponds to, for example, the antenna section in Fig. 1 used to transmit a transmission signal u1(i). Also, the antenna 2001_2 in Fig. 20 corresponds to, for example, the antenna section in Fig. 1 used to transmit a transmission signal u2(i). The correspondence between Figs. 20 and 1 is not limited thereto.

[0199] Antennas 2002_1 and 2002_2 in Fig. 20 are reception antennas. The antenna 2002_1 in Fig. 20 corresponds to the antenna section #X (1901X) in Fig. 19. The antenna 2002_2 in Fig. 20 corresponds to the antenna section #Y (1901Y) in Fig. 19.

[0200] As in Fig. 20, the signal transmitted from the transmission antenna 2001_1 is represented by u1(i), the signal transmitted from the transmission antenna 2001_2 is represented by u2(i), the signal received by the reception antenna 2002_1 is represented by r1(i), and the signal received by the reception antenna 2002_2 is represented by r2(i). Here, i represents a symbol number and is, for example, an integer equal to or greater than 0.

[0201] In addition, a propagation coefficient from the transmission antenna 2001_1 to the reception antenna 2002_1 is represented by h11(i), a propagation coefficient from the transmission antenna 2001_1 to the reception antenna 2002_2 is represented by h21(i), a propagation coefficient from the transmission antenna 2001_2 to the reception antenna 2002_1 is represented by h12(i), and a propagation coefficient from the transmission antenna 2001_2 to the reception antenna 2002_2 is represented by h22(i). Accordingly, the following Expression (41) as a relational expression holds. [Math. 41] r 1 i r 2 i = h 11 i h 12 i h 21 i h 22 i u 1 i u 2 i + n 1 i n 2 i Here, n1(i) and n2(i) represent noise.

[0202] The modulated signal u1 channel estimator 1905_1 in Fig. 19 receives the baseband signal 1904X, performs channel estimation of the modulated signal u1, that is, estimates h11(i) in Expression (41), by using the preamble and / or the pilot symbols in Figs. 8 and 9 (or Figs. 10 and 11), and outputs a channel estimation signal 1906_1.

[0203] The modulated signal u2 channel estimator 1905_2 receives the baseband signal 1904X, performs channel estimation of the modulated signal u2, that is, estimates h12(i) in Expression (41), by using the preamble and / or the pilot symbols in Figs. 8 and 9 (or Figs. 10 and 11), and outputs a channel estimation signal 1906_2.

[0204] The modulated signal u1 channel estimator 1907_1 receives the baseband signal 1904Y, performs channel estimation of the modulated signal u1, that is, estimates h21(i) in Expression (41), by using the preamble and / or the pilot symbols in Figs. 8 and 9 (or Figs. 10 and 11), and outputs a channel estimation signal 1908_1.

[0205] The modulated signal u2 channel estimator 1907_2 receives the baseband signal 1904Y, performs channel estimation of the modulated signal u2, that is, estimates h22(i) in Expression (41), by using the preamble and / or the pilot symbols in Figs. 8 and 9 (or Figs. 10 and 11), and outputs a channel estimation signal 1908_2.

[0206] A control information decoder 1909 receives the baseband signals 1904X and 1904Y, demodulates and decodes the control information in Figs. 8 and 9 (or Figs. 10 and 11), and outputs the control signal 1910 including the control information.

[0207] A signal processor 1911 receives the channel estimation signals 1906_1, 1906_2, 1908_1, and 1908_2, the baseband signals 1904X and 1904Y, and the control signal 1910. The signal processor 1911 performs demodulation and decoding by using the relationship in Expression (41) on the basis of the control information in the control signal 1910 (for example, information about a modulation scheme and a scheme related to error-correcting code), and outputs reception data 1912.

[0208] The control signal 1910 need not necessarily be a signal generated by using the method illustrated in Fig. 19. For example, the control signal 1910 in Fig. 19 may be a signal generated on the basis of information transmitted by the transmission apparatus (Fig. 1) as a communication partner of Fig. 19. Alternatively, the reception apparatus in Fig. 19 may include an input section, and the control signal 1910 may be generated on the basis of information input from the input section.<Example of Configuration of Antenna Section>

[0209] Next, a description will be given of the configuration of the antenna section in which the control signal 1910 exists as input. Fig. 21 is a diagram illustrating an example of the configuration of the antenna section in Fig. 19 (the antenna section #X (1901X) or the antenna section #Y (1901Y)). The example in Fig. 19 is an example in which the antenna section is constituted by four antennas 2101_1 to 2101_4.

[0210] A multiplier 2103_1 receives a reception signal 2102_1 received by the antenna 2101_1 and a control signal 2100. On the basis of information about a multiplication coefficient included in the control signal 2100, the multiplier 2103_1 multiplies the reception signal 2102_1 by the multiplication coefficient, and outputs a multiplied signal 2104_1.

[0211] When the reception signal 2102_1 is represented by Rx1(t) (t is time) and the multiplication coefficient is represented by D1 (D1 can be defined as a complex number and thus may be a real number), the multiplied signal 2104_1 is expressed by Rx1(t)×D1.

[0212] A multiplier 2103_2 receives a reception signal 2102_2 received by the antenna 2101_2 and the control signal 2100. On the basis of information about a multiplication coefficient included in the control signal 2100, the multiplier 2103_2 multiplies the reception signal 2102_2 by the multiplication coefficient, and outputs a multiplied signal 2104_2.

[0213] When the reception signal 2102_2 is represented by Rx2(t) and the multiplication coefficient is represented by D2 (D2 can be defined as a complex number and thus may be a real number), the multiplied signal 2104_2 is expressed by Rx2(t)×D2.

[0214] A multiplier 2103_3 receives a reception signal 2102_3 received by the antenna 2101_3 and the control signal 2100. On the basis of information about a multiplication coefficient included in the control signal 2100, the multiplier 2103_3 multiplies the reception signal 2102_3 by the multiplication coefficient, and outputs a multiplied signal 2104_3.

[0215] When the reception signal 2102_3 is represented by Rx3(t) and the multiplication coefficient is represented by D3 (D3 can be defined as a complex number and thus may be a real number), the multiplied signal 2104_3 is expressed by Rx3(t)×D3.

[0216] A multiplier 2103_4 receives a reception signal 2102_4 received by the antenna 2101_4 and the control signal 2100. On the basis of information about a multiplication coefficient included in the control signal 2100, the multiplier 2103_4 multiplies the reception signal 2102_4 by the multiplication coefficient, and outputs a multiplied signal 2104_4.

[0217] When the reception signal 2102_4 is represented by Rx4(t) and the multiplication coefficient is represented by D4 (D4 can be defined as a complex number and thus may be a real number), the multiplied signal 2104_4 is expressed by Rx4(t)×D4.

[0218] A combiner 2105 receives the multiplied signals 2104_1, 2104_2, 2104_3, and 1004_4. The combiner 2105 combines the multiplied signals 2104_1, 2104_2, 2104_3, and 2104_4, and outputs a combined signal 2106. The combined signal 2106 is expressed by Rx1(t)×D1 + Rx2(t)×D2 + Rx3(t)×D3 + Rx4(t)×D4.

[0219] In Fig. 21, a description is given of an example in which the antenna section is constituted by four antennas (and four multipliers), but the number of antennas is not limited to four, and is it sufficient that the antenna section be constituted by two or more antennas.

[0220] In a case where the antenna section #X (1901X) in Fig. 19 has the configuration in Fig. 21, the reception signal 1902X corresponds to the combined signal 2106 in Fig. 21 and the control signal 1910 corresponds to the control signal 2100 in Fig. 21. In a case where the antenna section #Y (1901Y) in Fig. 19 has the configuration in Fig. 21, the reception signal 1902Y corresponds to the combined signal 2106 in Fig. 21 and the control signal 1910 corresponds to the control signal 2100 in Fig. 21.

[0221] However, the antenna section #X (1901X) and the antenna section #Y (1901Y) need not necessarily have the configuration as in Fig. 21, and the antenna section need not necessarily receive the control signal 1910, as described above. The antenna section #X (1901X) and the antenna section #Y (1901Y) each may be one antenna.

[0222] The control signal 1910 may be generated on the basis of information transmitted by the transmission apparatus as a communication partner. Alternatively, the reception apparatus may include an input section, and the control signal 1910 may be generated on the basis of information input from the input section.

[0223] As described above, in the present embodiment, the transmission apparatus in Fig. 1 is able to transmit modulated signals (baseband signals) for multiple users at identical times and identical frequencies (bands) by using multiple antennas. Accordingly, the data transmission efficiently of the transmission apparatus in Fig. 1 can be increased. The transmission apparatus in Fig. 1 sets, for each user, whether to transmit multiple streams or a single stream (or not to transmit a modulated signal), and also sets, for each user, a modulation scheme (a set of modulation schemes in a case where there are multiple mappers) and an error-correcting coding scheme, thereby being able to preferably control the data transmission efficiency.

[0224] When the transmission apparatus in Fig. 1 transmits multiple modulated signals (baseband signals) to users, performing phase change increases a possibility of being able to avoid falling into a steady reception state in an environment in which direct waves are dominant. Accordingly, the data reception quality at the reception apparatus as a communication partner can be improved.(Second Embodiment)

[0225] In the present embodiment, a description will be given of an example of a communication apparatus including the transmission apparatus in Fig. 1 described in the first embodiment, a communication apparatus including the reception apparatus in Fig. 19 described in the first embodiment, and a flow of communication between the communication apparatuses.

[0226] For the description given below, the communication apparatus including the transmission apparatus in Fig. 1 is called a "base station (access point (AP))", and the communication apparatus including the reception apparatus in Fig. 19 is called a "terminal".

[0227] Thus, the user #1 signal processor 102_1 in Fig. 1 is a signal processor for generating a modulated signal for transmitting data to a terminal #1, the user #2 signal processor 102_2 is a signal processor for generating a modulated signal for transmitting data to a terminal #2, and the user #M signal processor 102_M is a signal processor for generating a modulated signal for transmitting data to a terminal #M.

[0228] Fig. 22 is a diagram illustrating an example of the configuration of the base station (AP) including the transmission apparatus in Fig. 1. In Fig. 22, the elements similar to those in Fig. 1 are denoted by the same numerals, and the description thereof is omitted.

[0229] A radio section group 153 receives a reception signal group 152 received by a reception antenna group 151. The radio section group 153 performs processing such as frequency conversion on the reception signal group 152, and outputs a baseband signal group 154 to a signal processor 155.

[0230] The signal processor 155 performs processing such as demodulation and error-correcting decoding on the baseband signal group input thereto, and outputs reception data 156 and control information 157. At this time, the control information 157 includes feedback information transmitted by each terminal.

[0231] A setter 158 receives base station (AP) setting information 159 and the control information 157. The setter 158 performs "deciding of an error-correcting coding method, a transmission method, a modulation scheme (or a modulation scheme set), and so forth in the user #1 signal processor 102_1 in Fig. 1", "deciding of an error-correcting coding method, a transmission method, a modulation scheme (or a modulation scheme set), and so forth in the user #2 signal processor 102_2 in Fig. 1", and "deciding of an error-correcting coding method, a transmission method, a modulation scheme (or a modulation scheme set), and so forth in the user #M signal processor 102_M in Fig. 1", and outputs a signal including the decided information as the control signal 100.

[0232] In addition, on the basis of the feedback information included in the control information 157 and transmitted by each terminal, the setter 158 decides the processing method to be used by the multiplexing signal processor 104, and outputs a signal including information about the decided processing information as the control signal 100.

[0233] In Fig. 22, the term "group" is used, but it is sufficient that a receiving section have one or more systems.

[0234] Fig. 23 is a diagram illustrating an example of the configuration of the terminal including the reception apparatus in Fig. 19. In Fig. 23, the elements that operate similarly to those in Fig. 19 are denoted by the same numerals.

[0235] The signal processor 1911 receives the channel estimation signal 1906_1, the channel estimation signal 1906_2, the baseband signal 1904_X, the channel estimation signal 1908_1, the channel estimation signal 1908_2, the baseband signal 1904_Y, and the 1910. The signal processor 1911 performs processing of demodulation and error-correcting decoding, and outputs the reception data 1912. In addition, the signal processor 1911 generates feedback information about the state of the reception signal on the basis of the signal transmitted by the base station (AP), and outputs feedback information 1999.

[0236] A transmission signal processor 1952 receives data 1951 and the feedback information 1999. The transmission signal processor 1952 performs processing such as error-correcting coding and modulation on the data 1951 and the feedback information 1999 to generate a baseband signal group 1953, and outputs the baseband signal group 1953 to a radio section group 1954.

[0237] The radio section group 1954 performs processing such as frequency conversion and amplification on the baseband signal group 1953 input thereto to generate a transmission signal group 1955. The radio section group 1954 outputs the transmission signal group 1955 to a transmission antenna group 1956. Subsequently, the transmission signal group 1955 is output as radio waves from the transmission antenna group 1956.

[0238] In Fig. 23, the term "group" is used, but it is sufficient that a transmitting section have one or more systems.

[0239] The base station (AP) transmits a signal to a terminal by using the configuration of the transmission apparatus in Fig. 1 and receives a signal from the terminal by using the configuration in Fig. 22. The terminal receives a signal from the base station (AP) by using the configuration of the reception apparatus in Fig. 19 and transmits a signal to the base station by using the configuration in Fig. 23. With these configurations, communication is performed between the base station (AP) and the terminal.

[0240] Next, a description will be given of a flow of communication between a base station (AP) and terminals.

[0241] Fig. 24 is a diagram illustrating an example of the relationship between a base station (AP) and terminals. In a base station (AP) 2400, the user #1 signal processor 102_1 in Fig. 1 generates a modulated signal to be transmitted to a terminal #1 (2401_1), for example, the user #1 signal processor 102_2 in Fig. 1 generates a modulated signal to be transmitted to a terminal #2 (2401_2), for example, and the user #M signal processor 102_M in Fig. 1 generates a modulated signal to be transmitted to a terminal #M (2401_M), for example.

[0242] The base station (AP) 2400 generates a transmission directivity 2411_1, and the terminal #1 (2401_1) generates a reception directivity 2421_1. With use of the transmission directivity 2411_1 and the reception directivity 2421_1, the transmission signal for the terminal #1 transmitted by the base station (AP) 2400 is received by the terminal #1 (2401_1).

[0243] Also, the base station (AP) 2400 generates a transmission directivity 2411_2, and the terminal #2 (2401_2) generates a reception directivity 2421_2. With use of the transmission directivity 2411_2 and the reception directivity 2421_2, the transmission signal for the terminal #2 transmitted by the base station (AP) 2400 is received by the terminal #2 (2401_2).

[0244] The base station (AP) 2400 generates a transmission directivity 2411_M, and the terminal #M (2401_M) generates a reception directivity 2421_M. With use of the transmission directivity 2411_M and the reception directivity 2421_M, the transmission signal for the terminal #M transmitted by the base station (AP) 2400 is received by the terminal #M (2401_M).

[0245] In the example in Fig. 24, it is assumed that the base station (AP) 2400 transmits the modulated signal to the terminal #1, the modulated signal to the terminal #2, and the modulated signal to the terminal #M by using identical times and identical frequencies (bands). This point has been described in the first embodiment. Fig. 24 illustrates "transmits the modulated signal to the terminal #1, the modulated signal to the terminal #2, and the modulated signal to the terminal #M by using identical times and identical frequencies (bands)", but this is merely an example. The number of modulated signals transmitted by the base station (AP) 2400 by using identical times and identical frequencies (bands) is not limited to this example. In addition, there may be a time at which modulated signals are not multiplexed.

[0246] Fig. 25 is a diagram illustrating an example of a temporal flow of communication between the base station (AP) and the terminals. Fig. 25 illustrates transmission signals of the base station (AP), transmission signals of the terminal #1, transmission signals of the terminal #2, and transmission signals of the terminal #M. The horizontal axis in Fig. 25 indicates time. A terminal other than the terminal #1, the terminal #2, and the terminal #M may transmit transmission signals.

[0247] As illustrated in Fig. 25, it is assumed that the terminal #1 issues an access request (transmission of data by the base station (AP)) 2501_1 to the base station (AP). Likewise, it is assumed that the terminal #2 issues an access request (transmission of data by the base station (AP)) 2501_2 to the base station (AP). It is assumed that the terminal #M issues an access request (transmission of data by the base station (AP)) 2501_M to the base station (AP).

[0248] It is assumed that the base station (AP) transmits a reference symbol (2502) in response to the access requests. For example, a PSK symbol that is known to the terminals is transmitted as the reference symbol 2502. However, the configuration of the reference symbol 2502 is not limited thereto. The reference symbol 2502 corresponds to the (common) reference signal 199 illustrated in Fig. 1.

[0249] Accordingly, the terminal #1 receives the reference symbol 2502 transmitted by the base station. Subsequently, for example, the terminal #1 estimates the reception state at each reception antenna of the terminal #1 and transmits information about the reception state at each reception antenna as feedback information 2503_1. Likewise, the terminal #2 receives the reference symbol 2502 transmitted by the base station. Subsequently, for example, the terminal #2 estimates the reception state at each reception antenna of the terminal #2 and transmits information about the reception state at each reception antenna as feedback information 2503_2. Likewise, the terminal #M receives the reference symbol 2502 transmitted by the base station. For example, the terminal #M estimates the reception state at each reception antenna of the terminal #M and transmits information about the reception state at each reception antenna as feedback information 2503_M.

[0250] The base station (AP) receives the pieces of feedback information transmitted by the individual terminals. For example, in Fig. 22, it is assumed that the control information 157 includes the pieces of feedback information transmitted by the individual terminals. The setter 158 in Fig. 22 receives the control information 157 including the pieces of feedback information transmitted by the individual terminals, decides the processing method to be performed by the multiplexing signal processor 104 in Fig. 1, and outputs the control signal 100 including this information.

[0251] Subsequently, the base station (AP) transmits each data symbol to each terminal (2504), for example, as illustrated in Fig. 24. Regarding "transmit each data symbol and so forth" 2504 illustrated in Fig. 25, symbols other than data symbols may exist, such as pilot symbols, control information symbols, reference symbols, and a preamble. The base station (AP) transmits modulated signals for individual terminals by using identical times and identical frequencies (bands). The details of this point have been described in the first embodiment.(Third Embodiment)

[0252] In the first embodiment, a description has been given mainly of an example in which, when the transmission apparatus in Fig. 1 generates multiple modulated signals to be transmitted to the user #p, the phase changer 305B (see Figs. 3 and 4) performs phase change on at least one modulated signal that has been subjected to precoding. In a third embodiment, a description will be given of processing in which the transmission apparatus in Fig. 1 switches, in accordance with the control signal 300, between "perform phase change and not perform phase change" in the phase changer 305B. Also, in the third embodiment, a description will be given of processing in which, when the transmission apparatus in Fig. 1 transmits a signal, the transmission scheme of the signal is changed on the basis of information received from a communication partner.

[0253] Hereinafter, a description will be given of a case where the base station (AP) including the transmission apparatus in Fig. 1 is communicating with terminals.

[0254] At this time, it is assumed that the base station (AP) is able to transmit multiple modulated signals including multiple streams of data to individual users (individual terminals) by using multiple antennas.

[0255] For example, it is assumed that the base station (AP) includes the transmission apparatus in Fig. 1 to transmit multiple modulated signals including multiple streams of data to the user #p (p is an integer from 1 to M) by using multiple antennas.

[0256] In Fig. 1, it is assumed that, when generating multiple modulated signals to be transmitted to the user #p, phase change is performed on at least one modulated signal that has been subjected to precoding. The operation for performing phase change has been described in the first embodiment, and thus the description thereof is omitted.

[0257] Here, it is assumed that the base station (AP) is able to switch between "perform phase change and not perform phase change" in accordance with a control signal when generating multiple modulated signals including multiple streams of data for the user #p. Specifically, it is assumed that it is possible to switch between "perform phase change and not perform phase change" in the phase changer 305B in Fig. 3 in accordance with the control signal 300. The operation for performing phase change has been described in the first embodiment. In the case of not performing phase change, the phase changer 305B outputs the signal 304B as 306B.

[0258] Thus, the following operations are performed in the case of performing phase change and in the case of not performing phase change.<Case of Performing Phase Change>

[0259] The base station (AP) performs phase change on at least one modulated signal, and then transmits multiple modulated signals by using multiple antennas.

[0260] The method for performing phase change on at least one modulated signal and transmitting multiple modulated signals by using multiple antennas has been described in the first embodiment, for example.<Case of Not Performing Phase Change>

[0261] The base station (AP) performs precoding (weight combining) on modulated signals (baseband signals) of multiple streams and transmits the generated multiple modulated signals by using multiple antennas. However, the precoder (weight combiner) need not necessarily perform precoding.

[0262] The base station (AP) transmits control information for notifying the terminal as a communication partner of the setting of performing or not performing phase change by using a preamble, for example.

[0263] As described above, "phase change is performed on at least one modulated signal". Specifically, a description has been given, with reference to Fig. 3, that phase change is performed on one modulated signal among multiple modulated signals. Now, a description will be given of the case of "performing phase change on multiple modulated signals" with reference to Fig. 26, instead of Fig. 3.

[0264] Fig. 26 is a diagram illustrating an example of the configuration of the signal processor 206 in Fig. 2, different from the example in Fig. 3. In Fig. 26, a point different from Fig. 3 will be described.

[0265] A phase changer 305A receives the control signal 300. On the basis of the control signal 300, the phase changer 305A determines whether or not to perform phase change. In a case where the phase changer 305A determines to perform phase change, the phase changer 305A performs phase change on the user #p weighted signal 304A (zp1'(t)) and outputs a phase-changed signal 306A. In a case where the phase changer 305A determines not to perform phase change, the phase changer 305A outputs the signal 306A without performing phase change on the user #p weighted signal 304A (zp1'(t)).

[0266] In Fig. 26, zp1(i) and zp2(i) are based on Expression (3) as in the first embodiment. In a case where phase change is performed on zp1(i) and zp2(i) in Fig. 26, it can be expressed by the following Expression (42). [Math. 42] zp 1 i zp 2 i = Yp i 0 0 yp i a b c d sp 1 i sp 2 i = e j × λp i 0 0 e j × δp i a b c d sp 1 i sp 2 i Here, λp(i) is a real number. Also, zp1(i) and zp2(i) are transmitted from the transmission apparatus at identical times and identical frequencies (identical frequency bands). The phase change in the phase changer 305A may be performed by using, for example, a method for changing the phase periodically or regularly.

[0267] In other embodiments such as the first embodiment and the second embodiment, each embodiment can be carried out even by using Fig. 26 instead of Fig. 3 as the configuration of the signal processor 206 in Fig. 2.

[0268] Next, a description will be given of communication between the base station (AP) and the terminal #p and processing based on data that is transmitted and received in the communication.

[0269] Fig. 27 is a diagram illustrating an example of communication between the base station (AP) and the terminal #p. Fig. 27 illustrates a state over time of a transmission signal from the base station (AP) and a state over time of a transmission signal from the terminal #p. In Fig. 27, the horizontal axis indicates time.

[0270] First, the base station (AP) transmits a transmission request 2071 indicating "request information for transmitting a modulated signal" to the terminal #p.

[0271] Subsequently, the terminal #p receives the transmission request 2701 transmitted by the base station (AP) and transmits a reception capability notification symbol 2702 indicating the reception capability of the terminal to the base station (AP).

[0272] The base station (AP) receives the reception capability notification symbol 2702 transmitted by the terminal #p, and decides an error-correcting coding method, a modulation scheme (or a set of modulation schemes), and a transmission method on the basis of the information of the reception capability notification symbol 2702. On the basis of these methods that have been decided, the base station (AP) performs error-correcting coding, mapping in the modulation scheme, and other signal processing (for example, precoding, phase change, and so forth) on the information (data) to be transmitted, and transmits a modulated signal 2703 including data symbols and so forth to the terminal #p.

[0273] The data symbols and so forth 2703 may include, for example, control information symbols. At this time, when transmitting data symbols by using "a transmission method for transmitting multiple modulated signals including multiple streams of data by using multiple antennas", a control symbol including information for notifying the communication partner whether phase change has been performed on at least one modulated signal or the foregoing phase change has not been performed may preferably be transmitted. Accordingly, the communication partner is able to easily change the demodulation method.

[0274] The terminal #p receives the data symbols and so forth 2703 transmitted by the base station and obtains data.

[0275] The communication between the base station (AP) and the terminal in Fig. 27 is performed by one or more terminals among the terminal #1 to the terminal #M and the base station (AP). The data symbols (including other symbols) transmitted to each terminal are transmitted by the base station by using identical times and identical frequencies (bands). This point has been described in the first embodiment, the second embodiment, and so forth.

[0276] Fig. 28 is a diagram illustrating an example of data included in the reception capability notification symbol 2702 transmitted by the terminal #p in Fig. 27. The data included in the reception capability notification symbol 2702 is, for example, data indicating the reception capability of the terminal #p. The terminal #p transmits the data indicating the reception capability to the base station (AP), and thereby the base station (AP) is able to transmit a transmission signal corresponding to the reception capability to the terminal #p.

[0277] In Fig. 28, 2801 denotes data about "support / not support demodulation of phase changed signal", and 2802 denotes data about "support / not support reception directivity control".

[0278] In the data 2801 about "support / not support demodulation of phase changed signal", "support demodulation of phase changed signal" means the following."Support demodulation of phase changed signal":

[0279] · This means that, in a case where the base station (AP) performs phase change on at least one modulated signal and transmits multiple modulated signals (multiple modulated signals including multiple streams) by using multiple antennas, the terminal #p is able to receive and demodulate the modulated signals. That is, this means that the terminal #p is able to perform demodulation in consideration of phase change and to obtain data. The transmission method for performing phase change on at least one modulated signal and transmitting multiple modulated signals by using multiple antennas has already been described in an embodiment.

[0280] In the data 2801 about "support / not support demodulation of phase changed signal ", "not support demodulation of phase changed signal" means the following."Not support demodulation of phase changed signal":

[0281] · This means that, in a case where the base station (AP) performs phase change on at least one modulated signal and transmits multiple modulated signals (multiple modulated signals including multiple streams) by using multiple antennas, the terminal #p is able to receive the modulated signals but is unable to demodulate the modulated signals. That is, this means that the terminal #p is unable to perform demodulation in consideration of phase change. The transmission method for performing phase change on at least one modulated signal and transmitting multiple modulated signals by using multiple antennas has already been described in an embodiment.

[0282] For example, it is assumed that the data 2801 about "support / not support demodulation of phase changed signal" (hereinafter referred to as "data 2801") is expressed by 1-bit data. Also, it is assumed that, in a case where the terminal #p "supports phase change" as described above, the terminal #p transmits the data 2801 as "0". Also, it is assumed that, in a case where the terminal #p "does not support phase change" as described above, the terminal #p transmits the data 2801 as "1". The base station (AP) receives the data 2801 transmitted by the terminal #p.

[0283] In a case where the data 2801 indicates "support phase change" (i.e., the data 2801 is "0") and the base station (AP) decides to transmit modulated signals of multiple streams to the terminal #p by using multiple antennas (for example, in the case of deciding to generate multiple modulated signals for transmitting multiple streams in the user #p signal processor 102_p illustrated in Fig. 1), the base station (AP) may generate modulated signals addressed to the user #p by using either of <Method #1> and <Method #2> described below and transmit the modulated signals. Alternatively, the base station (AP) generates modulated signals addressed to the user #p by using <Method #2> described below and transmits the modulated signals.<Method #1>

[0284] The base station (AP) performs precoding (weight combining) on modulated signals (baseband signals) of multiple streams to be transmitted to the terminal #p and transmits the generated multiple modulated signals by using multiple antennas. At this time, phase change is not performed. However, the precoder (weight combiner) need not necessarily perform precoding, as described above.<Method #2>

[0285] The base station (AP) performs phase change on at least one modulated signal among multiple modulated signals to be transmitted to the terminal #p. Subsequently, the base station (AP) transmits the multiple modulated signals to the terminal #p by using multiple antennas.

[0286] Here, it is important that the transmission methods selectable by the base station (AP) include <Method #2>. Thus, the base station (AP) may transmit the modulated signals by using a method other than <Method #1> and <Method #2>.

[0287] On the other hand, in a case where the data 2801 indicates "not support phase change" (i.e., the data 2801 is "1") and the base station (AP) decides to transmit modulated signals of multiple streams to the terminal #p by using multiple antennas, the base station (AP) transmits the modulated signals to the terminal #p by using <Method #1>, for example.

[0288] Here, it is important that, when the base station (AP) transmits the modulated signals to the terminal #p, the transmission methods selectable by the base station (AP) do not include <Method #2>. Thus, the base station (AP) may transmit the modulated signals to the terminal #p by using a method that is different from <Method #1> and that is not <Method #2>.

[0289] The reception capability notification symbol 2702 may include information other than the data 2801. For example, the reception capability notification symbol 2702 may include the data 2802 about "support / not support reception directivity control" indicating whether or not the reception apparatus of the terminal supports reception directivity control (hereinafter referred to as "data 2802"). Thus, the configuration of the reception capability notification symbol 2702 is not limited to that in Fig. 28.

[0290] For example, in a case where the terminal #p is able to perform reception directivity control, the data 2802 is set to "0". In a case where the terminal #p is unable to perform reception directivity control, the data 2802 is set to "1".

[0291] The terminal #p transmits the reception capability notification symbol 2702 including the data 2802, and the base station (AP) determines, on the basis of the reception capability notification symbol 2702, whether or not the terminal #p is able to perform reception directivity control. If the base station (AP) determines that the terminal #p "supports reception directivity control", the base station (AP) and the terminal #p may transmit training symbols, reference symbols, control information symbols, and so forth for reception directivity control of the terminal #p.

[0292] Fig. 29 is a diagram illustrating an example of data included in the reception capability notification symbol 2702 transmitted by the terminal #p in Fig. 27, different from the example in Fig. 28. The data 2801 is the same as that in Fig. 28.

[0293] Hereinafter, a description will be given of data 2901 about "support / not support reception for multiple streams" in Fig. 29.

[0294] In the data 2901 about "support / not support reception for multiple streams", "support reception for multiple streams" means the following."Support reception for multiple streams":

[0295] · This means that, in a case where the base station (AP) transmits multiple modulated signals addressed to the terminal #p from multiple antennas to transmit multiple streams to the terminal #p, the terminal #p is able to receive and demodulate the multiple modulated signals addressed to the terminal #p and transmitted by the base station.

[0296] However, for example, in a case where the base station (AP) transmits multiple modulated signals addressed to the terminal #p from the multiple antennas, it is not concerned about whether or not phase change has been performed. That is, in a case where multiple transmission methods are defined as a transmission method in which the base station (AP) transmits multiple modulated signals addressed to the terminal #p by using multiple antennas to transmit multiple streams to the terminal #p, it is sufficient that there be at least one transmission method that allows the terminal #p to demodulate the modulated signals.

[0297] In the data 2901 about "support / not support reception for multiple streams", "not support reception for multiple streams" means the following."Not support reception for multiple streams":

[0298] · In a case where multiple transmission methods are defined as a transmission method in which the base station transmits multiple modulated signals addressed to the terminal #p by using multiple antennas to transmit multiple streams to the terminal #p, the terminal is unable to demodulate the modulated signals even if the base station transmits the modulated signals by using any transmission method.

[0299] For example, it is assumed that the data 2901 about "support / not support reception for multiple streams" (hereinafter referred to as "data 2901") is expressed by 1-bit data. In a case where the terminal #p "supports reception for multiple streams", the terminal #p sets "0" as the data 2901. In a case where the terminal #p "does not support reception for multiple streams", the terminal #p sets "1" as the data 2901.

[0300] The base station (AP) performs phase change on at least one modulated signal among multiple modulated signals (multiple modulated signals including multiple streams). Thus, in a case where the terminal #p does not support reception for multiple streams, the base station (AP) is unable to transmit multiple modulated signals, and eventually is unable to perform phase change.

[0301] Thus, in a case where the terminal #p sets "0" as the data 2901, the data 2801 is valid. At this time, the base station (AP) decides, on the basis of the data 2801 and the data 2901, a transmission method for transmitting data.

[0302] In a case where the terminal #p sets "1" as the data 2901, the data 2801 is invalid. At this time, the base station (AP) decides, on the basis of the data 2901, a transmission method for transmitting data.

[0303] In the above-described manner, the terminal transmits the reception capability notification symbol 2702, and the base station (AP) decides, on the basis of the symbol, a transmission method for transmitting data. Accordingly, it is possible to reduce cases where data is transmitted by a transmission method that does not allow the terminal #p to perform demodulation, which is advantageous in that data can be appropriately transmitted to the terminal #p. Thus, the data transmission efficiency of the base station (AP) can be increased.

[0304] In addition, there is the data 2801 about "support / not support demodulation of phase changed signal" as the reception capability notification symbol 2702. Thus, in a case where the terminal #p that supports demodulation of phase changed signal communicates with the base station (AP), the base station (AP) is able to appropriately select a mode in which "modulated signals are transmitted by using a transmission method that performs phase change". Accordingly, the terminal #p is able to obtain data of high reception quality even in an environment in which direct waves are dominant. In addition, in a case where the terminal #p that does not support demodulation of phase changed signal communicates with the base station (AP), the base station (AP) is able to appropriately select a transmission method that allows the terminal to perform reception. Accordingly, the data transmission efficiency can be increased.

[0305] Fig. 27 illustrates the transmission signal from the base station (AP) and the transmission signal from the terminal #p, but the transmission signals are not limited thereto. For example, the signal illustrated as the transmission signal from the base station (AP) in Fig. 27 may be the transmission signal from the terminal, and the signal illustrated as the transmission signal from the terminal #p in Fig. 27 may be the transmission signal from the base station (AP).

[0306] Alternatively, the signal illustrated as the transmission signal from the base station (AP) in Fig. 27 may be a transmission signal from a terminal other than the terminal #p. That is, the transmission and reception of the signals illustrated in Fig. 27 may be transmission and reception between terminals.

[0307] Alternatively, the transmission and reception of the signals illustrated in Fig. 27 may be transmission and reception between base stations (APs).

[0308] The transmission and reception is not limited to these examples, and any communication between communication apparatuses may be performed.

[0309] The data symbols in the data symbols and so forth 2703 in Fig. 27 may be a signal of a multi-carrier scheme such as OFDM or may be a signal of a single-carrier scheme. Likewise, the reception capability notification symbol 2702 in Fig. 27 may be a signal of a multi-carrier scheme such as OFDM or may be a signal of a single-carrier scheme.

[0310] For example, in a case where the reception capability notification symbol 2702 in Fig. 27 is of a single-carrier scheme, the terminal is able to reduce power consumption in the case of Fig. 27.

[0311] In the description given above, when the base station (AP) is communicating with multiple terminals, the base station (AP) receives reception capability notification symbols (see 2702) from the multiple terminals. At this time, each terminal transmits, as the "reception capability notification symbol", the data illustrated in Fig. 28 or 29, for example, and the base station (AP) decides a transmission method for modulated signals for each terminal. When the base station (AP) transmits modulated signals to the multiple terminals, the base station (AP) transmits the modulated signals addresses to the individual terminals by using the methods described in the first embodiment and the second embodiment, for example.

[0312] Next, a description will be given of another example of the reception capability notification symbol 2702 with reference to Fig. 30.

[0313] Fig. 30 is a diagram illustrating an example of data included in the reception capability notification symbol 2702 transmitted by the terminal #p in Fig. 27, different from the examples in Figs. 28 and 29. The data 2801 about "support / not support demodulation of phase changed signal" is the same as those in Figs. 28 and 29. Also, the data 2901 about "support / not support reception for multiple streams" is the same as that in Fig. 29.

[0314] A description will be given of data 3001 about "supported schemes" (hereinafter referred to as "data 3001") in Fig. 30. It is assumed that the transmission of modulated signals to the terminals by the base station (AP) and the transmission of modulated signals to the base station (AP) by the terminals in Fig. 24 are the transmission of modulated signals in a communication scheme in a specific frequency (band). Also, it is assumed that a communication scheme #A and a communication scheme #B exist as examples of the "communication scheme in a specific frequency (band)".

[0315] It is assumed that "communication scheme #A" does not support a "scheme for transmitting multiple modulated signals including multiple streams by using multiple antennas". That is, there is no option of a "scheme for transmitting multiple modulated signals including multiple streams by using multiple antennas" as "communication scheme #A". In addition, it is assumed that "communication scheme #B" supports a "scheme for transmitting multiple modulated signals including multiple streams by using multiple antennas". That is, the "scheme for transmitting multiple modulated signals including multiple streams by using multiple antennas" is selectable as "communication scheme #B".

[0316] For example, it is assumed that the data 3001 is made up of 2 bits. Also, it is assumed that the 2-bit data is set as follows.

[0317] · In a case where the terminal #p supports only "communication scheme #A", the data 3001 is set to "01". In a case where the data 3001 is set to "01", even if the base station (AP) transmits a modulated signal of "communication scheme #B", the terminal #p is unable to demodulate the modulated signal and obtain data. · In a case where the terminal #p supports only "communication scheme #B", the data 3001 is set to "10". In a case where the data 3001 is set to "10", even if the base station (AP) transmits a modulated signal of "communication scheme #A", the terminal #p is unable to demodulate the modulated signal and obtain data. · In a case where the terminal #p supports both "communication scheme #A" and "communication scheme #B", the data 3001 is set to "11".

[0318] Next, a description will be given of data 3002 about "support / not support multi-carrier scheme" (hereinafter referred to as data 3002) in Fig. 30. It is assumed that "communication scheme #A" is able to select a "single-carrier scheme" or a "multi-carrier scheme such as the OFDM scheme" as a transmission method for modulated signals. Also, it is assumed that "communication scheme #B" is able to select a "single-carrier scheme" or a "multi-carrier scheme such as the OFDM scheme" as a transmission method for modulated signals.

[0319] For example, it is assumed that the data 3002 is made up of 2 bits. Also, it is assumed that the 2-bit data is set as follows.

[0320] · In a case where the terminal #p supports only "single-carrier scheme", the data 3002 is set to "01". In a case where the data 3002 is set to "01", even if the base station (AP) transmits a modulated signal of "multi-carrier scheme such as the OFDM scheme", the terminal #p is unable to demodulate the modulated signal and obtain data. · In a case where the terminal #p supports only "multi-carrier scheme such as the OFDM scheme", the data 3002 is set to "10". In a case where the data 3002 is set to "10", even if the base station (AP) transmits a modulated signal of "single-carrier scheme ", the terminal #p is unable to demodulate the modulated signal and obtain data. · In a case where the terminal #p supports both "single-carrier scheme" and "multi-carrier scheme such as the OFDM scheme", the data 3002 is set to "11".

[0321] Next, a description will be given of data 3003 about "supported error-correcting coding schemes" (hereinafter referred to as data 3003) in Fig. 30. For example, it is assumed that "error-correcting coding scheme #C" is an "error-correcting coding method that supports one or more code rates with a code length (block length) of c bits (c is an integer equal to or greater than 1)". It is assumed that "error-correcting coding scheme #D" is an "error-correcting coding method that supports one or more code rates with a code length (block length) of d bits (d is an integer equal to or greater than 1 and is greater than c (d>c))". As a method that supports one or more code rates, an error-correcting code that varies according to a code rate may be used, or one or more code rates may be supported by puncturing. In addition, one or more code rates may be supported by both of them.

[0322] It is assumed that only "error-correcting coding scheme #C" is selectable in "communication scheme #A" and that "error-correcting coding scheme #C" and "error-correcting coding scheme #D" are selectable in "communication scheme #B".

[0323] For example, it is assumed that the data 3003 is made up of 2 bits. Also, it is assumed that the 2-bit data is set as follows.

[0324] · In a case where the terminal #p supports only "error-correcting coding scheme #C", the data 3003 is set to "01". In a case where the data 3003 is set to "01", even if the base station (AP) generates and transmits a modulated signal by using "error-correcting coding scheme #D", the terminal #p is unable to demodulate and decode the modulated signal and obtain data. · In a case where the terminal #p supports only "error-correcting coding scheme #D", the data 3003 is set to "10". In a case where the data 3003 is set to "10", even if the base station (AP) generates and transmits a modulated signal by using "error-correcting coding scheme #C", the terminal #p is unable to demodulate and decode the modulated signal and obtain data. · In a case where the terminal #p supports both "error-correcting coding scheme #C" and "error-correcting coding scheme #D", the data 3003 is set to "11".

[0325] The base station (AP) receives the reception capability notification symbol 2702 that is transmitted by the terminal #p and that has the configuration illustrated in Fig. 30, for example. Subsequently, the base station (AP) decides a method for generating modulated signals including data symbols addressed to the terminal #p on the basis of the content of the reception capability notification symbol 2702, and transmits the modulated signals addressed to the terminal #p.

[0326] Characteristic points at this time will be described.[Example 1]

[0327] In a case where the terminal #p transmits the data 3001 set to "01" (i.e., "communication scheme #A" is supported), the base station (AP) that has obtained the data determines that the data 3003 is invalid because "error-correcting coding scheme #D" is not selectable in "communication scheme #A". When generating modulated signals addressed to the terminal #p, the base station (AP) performs error-correcting coding by using "error-correcting coding scheme #C".[Example 2]

[0328] In a case where the terminal #p transmits the data 3001 set to "01" (i.e., "communication scheme #A" is supported), the base station (AP) that has obtained the data determines that the data 2801 and the data 2901 are invalid because the "scheme for transmitting multiple modulated signals including multiple streams by using multiple antennas" is not supported in "communication scheme #A". When generating modulated signals addressed to the terminal, the base station (AP) generates a modulated signal of a single stream and transmits it.

[0329] In addition to the above, a case with the following constraints will be discussed.[Constraint condition 1]

[0330] In "communication scheme #B", it is assumed that, in the single-carrier scheme, in the "scheme for transmitting multiple modulated signals including multiple streams by using multiple antennas", the scheme for "performing phase change on at least one modulated signal among multiple modulated signals" is not supported (other schemes may be supported), and that, in the multi-carrier scheme such as the OFDM scheme, at least the scheme for "performing phase change on at least one modulated signal among multiple modulated signals" is supported (other schemes may be supported).

[0331] In this case, the following arises.[Example 3]

[0332] In a case where the terminal #p transmits the data 3002 set to "01" (i.e., only the single-carrier scheme is supported), the base station (AP) that has obtained the data determines that the data 2801 is invalid. When generating modulated signals addressed to the terminal #p, the base station (AP) does not use the scheme for "performing phase change on at least one modulated signal among multiple modulated signals".

[0333] Fig. 30 is an example of the reception capability notification symbol 2702 transmitted by the terminal #p. As described above by using Fig. 30, in a case where the terminal #p transmits multiple pieces of reception capability information (for example, the data 2801, the data 2901, the data 3001, the data 3002, and the data 3003 in Fig. 30), the base station (AP) may need to determine that some of the multiple pieces of reception capability information are invalid when deciding a method for generating modulated signals addressed to the terminal #p on the basis of the reception capability notification symbol 2702. In consideration of this, if the terminal #p bundles the multiple pieces of reception capability information and transmits it as the reception capability notification symbol 2702, the base station (AP) is able to easily decide the generation of the modulated signals addressed to the terminal #p in a short processing time.

[0334] The data structure descried in the third embodiment is merely an example and is not limited thereto. In addition, the number of bits of each piece of data and a bit setting method are not limited to the examples described in the third embodiment.(Fourth Embodiment)

[0335] In the first embodiment, the second embodiment, and the third embodiment, a description has been given that either of the case of generating multiple modulated signals including multiple streams and the case of generating a modulated signal of a single stream is possible in the user #p signal processor 102_p (p is an integer from 1 to M) in Fig. 1. In a fourth embodiment, a description will be given of another example of the configuration of the user #p signal processor 102_p at this time.

[0336] Fig. 31 is a diagram illustrating an example of the configuration of the user #p signal processor 102_p. In Fig. 31, the elements that operate similarly to those in Fig. 2 are denoted by the same numerals. In Fig. 31, the detailed operation of the signal processor 206 has been described in the first embodiment and thus the description thereof is omitted. Hereinafter, characteristic operations will be described.

[0337] It is assumed that the control signal 200 includes information indicating which of the "method for transmitting a modulated signal of a single stream" and the "method for transmitting multiple modulated signals including multiple streams" is to be used in each user signal processor.

[0338] In a case where generation of modulated signals using the "method for transmitting multiple modulated signals including multiple streams" is designated by the control signal 200 in the user #p signal processor 102_p, the signal processor 206 generates multiple modulated signals including multiple streams, outputs a user #p processed signal 206_A to a signal selector 3101, and outputs a user #p processed signal 206_B to an output controller 3102.

[0339] The signal selector 3101 receives the control signal 200, the user #p processed signal 206_A, and the mapped signal 205_1. Since the generation of modulated signals using the "method for transmitting multiple modulated signals including multiple streams" is designated by the control signal 200, the signal selector 3101 outputs the user #p processed signal 206_A as a selected signal 206_A'. The selected signal 206_A' corresponds to the user #p first baseband signal 103_p_1 in Fig. 1.

[0340] The output controller 3102 receives the control signal 200 and the user #p processed signal 206_B. Since the generation of modulated signals using the "method for transmitting multiple modulated signals including multiple streams" is designated by the control signal 200, the output controller 3102 outputs the user #p processed signal 206_B as an output signal 206_B'. The output signal 206_B' corresponds to the user #p second baseband signal 103_p_2 in Fig. 1.

[0341] In the user #p signal processor 102_p, in a case where the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the signal processor 206 does not operate.

[0342] In addition, the mapper 204 does not output the mapped signal 205_2.

[0343] The signal selector 3101 receives the control signal 200, the user #p processed signal 206_A, and the mapped signal 205_1. Since the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the signal selector 3101 outputs the mapped signal 205_1 as the selected signal 206_A'. The selected signal 206_A' corresponds to the user #p first baseband signal 103_p_1 in Fig. 1.

[0344] The output controller 3102 receives the control signal 200 and the user #p processed signal 206_B. Since the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the output controller 3102 does not output the output signal 206_B'.

[0345] With the above-described operation, in the user #p signal processor 102_p in Fig. 1, outputting of a modulated signal can be realized in either of the case of generating multiple modulated signals including multiple streams and the case of generating a modulated signal of a single stream.

[0346] A description has been given that either of the case of generating multiple modulated signals including multiple streams and the case of generating a modulated signal of a single stream is possible in the user #p signal processor 102_p (p is an integer from 1 to M) in Fig. 1. Now, with reference to Fig. 32, a description will be given of an example of the configuration of the user #p signal processor 102 _p different from the example in Fig. 31.

[0347] Fig. 32 is a diagram illustrating an example of the configuration of the user #p signal processor 102_p. The elements similar to those in Figs. 2 and 31 are denoted by the same numerals. In Fig. 32, the detailed operation of the signal processor 206 has been described in the first embodiment, and thus the description thereof is omitted. Hereinafter, characteristic operations will be described.

[0348] It is assumed that the control signal 200 includes information indicating whether the "scheme for transmitting a modulated signal of a single stream" or the "scheme for transmitting multiple modulated signals including multiple streams" is to be used in each user signal processor.

[0349] In a case where the generation of modulated signals using the "method for transmitting multiple modulated signals including multiple streams" is designated by the control signal 200 in the user #p signal processor 102_p, the signal processor 206 operates, generates multiple modulated signals including multiple streams, and outputs the user #p processed signals 206_A and 206_B.

[0350] The signal selector 3101 receives the control signal 200, the user #p processed signal 206_A, and a processed signal 3202_1. Since the generation of modulated signals using the "method for transmitting multiple modulated signals including multiple streams" is designated by the control signal 200, the signal selector 3101 outputs the user #p processed signal 206_A as the selected signal 206_A'. The selected signal 206_A' corresponds to the user #p first baseband signal 103_p_1 in Fig. 1.

[0351] A signal selector 3203 receives the control signal 200, the user #p processed signal 206_B, and a processed signal 3202_2. Since the generation of modulated signals using the "method for transmitting multiple modulated signals including multiple streams" is designated by the control signal 200, the signal selector 3203 outputs the user #p processed signal 206_B as the selected signal 206_B'. The selected signal 206_B' corresponds to the user #p second baseband signal 103_p_2 in Fig. 1.

[0352] In the user #p signal processor 102_p, in a case where the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the signal processor 206 does not operate.

[0353] In addition, the mapper 204 does not output the mapped signal 205_2.

[0354] A processor 3201 receives the control signal 200 and the mapped signal 205_1. Since the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the processor 3201 generates and outputs processed signals 3202_1 and 3202_2 corresponding to the mapped signal 205_1. At this time, it is assumed that the data included in the mapped signal 205_1 is identical to the data included in the processed signal 3202_1, and the data included in the mapped signal 205_1 is identical to the data included in the processed signal 3202_2.

[0355] The signal selector 3101 receives the control signal 200, the user #p processed signal 206_A, and the processed signal 3202_1. Since the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the signal selector 3101 outputs the processed signal 3202_1 as the selected signal 206_A'. The selected signal 206_A' corresponds to the user #p first baseband signal 103_p_1 in Fig. 1.

[0356] The signal selector 3203 receives the control signal 200, the user #p processed signal 206_B, and the processed signal 3202_2. Since the generation of a modulated signal using the "method for transmitting a modulated signal of a single stream" is designated by the control signal 200, the signal selector 3203 outputs the processed signal 3202_2 as the selected signal 206_B'. The selected signal 206_B' corresponds to the user #p first baseband signal 103_p_2 in Fig. 1.

[0357] A description has been given above of operation examples in the case of generating multiple modulated signals including multiple streams and the case of generating a modulated signal of a single stream in the user #p signal processor 102_p (p is an integer from 1 to M) in Fig. 1 by using two example configurations. In the signal processors for individual users in Fig. 1, either of the above described generation of multiple modulated signals including multiple streams and generation of a modulated signal of a single stream may be performed. In addition, as described in the first embodiment and so forth, the signal processors for users in Fig. 1 do not necessarily output modulated signals.(Supplement)

[0358] In Expression (1) to Expression (42), an expression of a function of i (symbol number) is included. With reference to Figs. 12 to 17, a description has been given that symbols may be arranged in the time-axis direction, the frequency-axis direction, or the time-axis and frequency-axis directions. Thus, an expression described as a function of i in Expression (1) to Expression (42) may be interpreted as a function of time, interpreted as a function of frequency, or interpreted as a function of time and frequency.

[0359] In this specification, for example, it is assumed that the transmission apparatus in Fig. 1 is able to generate and transmit "modulated signals using the OFDM scheme and modulated signals of a single-carrier scheme in a specific frequency band". At this time, in a case where the transmission apparatus in Fig. 1 transmits multiple modulated signals (baseband signals) for a certain user and performs phase change as described in this specification, setting may be performed so that the period of phase change in the case of using the OFDM scheme is different from the period of phase change in the case of using the single-carrier scheme. Since the frame configurations are different, it may be preferable to perform setting so that the periods are different. However, the period of phase change in the case of using the OFDM scheme may be identical to the period of phase change in the case of using the single-carrier scheme.

[0360] In addition, the user #1 signal processor 102_1 to the user #M signal processor 102_M in Fig. 1 may generate modulated signals of a single-carrier or may generate modulated signals of a multi-carrier scheme such as the OFDM scheme, for example. Thus, single-carrier modulated signals and multi-carrier modulated signals such as the OFDM scheme may be transmitted from the transmission apparatus in Fig. 1 by using identical times and identical frequencies (frequency bands that overlap each other at least partially).

[0361] For example, the user #1 signal processor 102_1 may generate the user #1 baseband signal 103_1_1 corresponding to a modulated signal of the single-carrier scheme and the user #1 baseband signal 103_1_2 corresponding to a modulated signal of the single-carrier scheme, the user #2 signal processor 102_2 may generate the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme, and the transmission apparatus in Fig. 1 may transmit "the user #1 baseband signal 103_1_1 corresponding to a modulated signal of the single-carrier scheme and the user #1 baseband signal 103_1_2 corresponding to a modulated signal of the single-carrier scheme" and "the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme" at identical times and identical frequencies (frequency bands that overlap each other at least partially). At this time, "the user #1 baseband signal 103_1_1 corresponding to a modulated signal of the single-carrier scheme and the user #1 baseband signal 103_1_2 corresponding to a modulated signal of the single-carrier scheme" may be baseband signals generated by using any of the methods: "perform precoding and phase change", "perform precoding", "not perform precoding but perform phase change", and "perform neither precoding nor phase change". Likewise, "the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme" may be baseband signals generated by using any of the methods: "perform precoding and phase change", "perform precoding", "not perform precoding but perform phase change", and "perform neither precoding nor phase change".

[0362] For another example, the user #1 signal processor 102_1 may generate a baseband signal of a single stream of the single-carrier scheme, the user #2 signal processor 102_2 may generate the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme, and the transmission apparatus in Fig. 1 may transmit "the baseband signal of a single stream of the single-carrier scheme" and "the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme" at identical times and identical frequencies (frequency bands that overlap each other at least partially). At this time, "the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme" may be baseband signals generated by using any of the methods: "perform precoding and phase change", "perform precoding", "not perform precoding but perform phase change", and "perform neither precoding nor phase change".

[0363] For another example, the user #1 signal processor 102_1 may generate the user #1 baseband signal 103_1_1 corresponding to a modulated signal of the single-carrier scheme and the user #1 baseband signal 103_1_2 corresponding to a modulated signal of the single-carrier scheme, the user #2 signal processor 102_2 may generate a baseband signal of a single stream of the multi-carrier scheme such as the OFDM scheme, and the transmission apparatus in Fig. 1 may transmit "the user #1 baseband signal 103_1_1 corresponding to a modulated signal of the single-carrier scheme and the user #1 baseband signal 103_1_2 corresponding to a modulated signal of the single-carrier scheme" and "the baseband signal of a single stream of the multi-carrier scheme such as the OFDM scheme" at identical times and identical frequencies (frequency bands that overlap each other at least partially). At this time, "the user #2 baseband signal 103_2_1 corresponding to a modulated signal of the multi-carrier scheme such as the OFDM scheme and the user #2 baseband signal 103_2_2 corresponding to a modulation scheme of the multi-carrier scheme such as the OFDM scheme" may be baseband signals generated by using any of the methods: "perform precoding and phase change", "perform precoding", "not perform precoding but perform phase change", and "perform neither precoding nor phase change".

[0364] For another example, the user #1 signal processor 102_1 may generate a baseband signal of a single stream of the single-carrier scheme, the user #2 signal processor 102_2 may generate a baseband signal of a single stream of the multi-carrier scheme such as the OFDM scheme, and the transmission apparatus in Fig. 1 may transmit "the baseband signal of a single stream of the single-carrier scheme" and "the baseband signal of a single stream of the multi-carrier scheme such as the OFDM scheme" at identical times and identical frequencies (frequency bands that overlap each other at least partially).

[0365] Figs. 2 and 31 illustrate the configurations in which each user signal processor includes one error-correcting encoder and one mapper, but the configuration is not limited thereto. For example, a configuration including a first error-correcting encoder and a first mapper for generating the user #p mapped signal (baseband signal) 205_1 for transmitting first data, and including a second error-correcting encoder and a second mapper for generating the user #p mapped signal (baseband signal) 205_2 for transmitting second data may be adopted. Alternatively, the number of error-correcting encoders and the number of mappers may be three.(Fifth Embodiment)

[0366] In the present embodiment, a description will be given of an example operation of a terminal by using the example described in the third embodiment. Fig. 34 is a diagram illustrating an example of the configuration of the terminal #p as a communication partner of the base station in Fig. 24. The terminal #p includes a transmission apparatus 3403, a reception apparatus 3404, and a control signal generator 3408.

[0367] The transmission apparatus 3403 receives data 3401, a signal group 3402, and a control signal 3409. The transmission apparatus 3403 generates a modulated signal corresponding to the data 3401 and the signal group 3402 and transmits the modulated signal from its antenna.

[0368] The reception apparatus 3404 receives a modulated signal transmitted by a communication partner, for example, the base station, performs signal processing, demodulation, and decoding on the modulated signal, and outputs a control information signal 3405 and reception data 3406 from the communication partner.

[0369] The control signal generator 3408 receives the control information signal 3405 from the communication partner and a setting signal 3407. On the basis of these pieces of information, the control signal generator 3408 generates the control signal 3409 and outputs it to the transmission apparatus 3403.

[0370] Fig. 35 is a diagram illustrating an example of the configuration of the reception apparatus 3404 of the terminal #p illustrated in Fig. 34. The reception apparatus 3404 includes an antenna section 3501, a radio section 3503, a channel estimator 3505, a signal processor 3509, and a control information decoder 3507.

[0371] The radio section 3503 receives a reception signal 3502 received by the antenna section 3501. The radio section 3503 performs processing such as frequency conversion on the reception signal 3502 to generate a baseband signal 3504. The radio section 3503 outputs the baseband signal 3504 to the channel estimator 3505, the control information decoder 3507, and the signal processor 3509.

[0372] The control information decoder 3507 receives the baseband signal 3504. The control information decoder 3507 outputs control information 3508, which is obtained by demodulating the control information symbols included in the baseband signal 3504.

[0373] The channel estimator 3505 receives the baseband signal 3504. The channel estimator 3505 extracts a preamble and pilot symbols included in the baseband signal 3504. The channel estimator 3505 estimates channel variation on the basis of the preamble and the pilot symbols, and generates a channel estimation signal 3506 indicating the estimated channel variation. The channel estimator 3505 outputs the channel estimation signal 3506 to the signal processor 3509.

[0374] The signal processor 3509 receives the baseband signal 3504, the channel estimation signal 3506, and the control information 3508. On the basis of the channel estimation signal 3506 and the control information 3508, the signal processor 3509 performs demodulation and error-correcting decoding on data symbols included in the baseband signal 3504, and generates reception data 3510. The signal processor 3509 outputs the reception data 3510.

[0375] Fig. 36 is a diagram illustrating an example of the frame configuration of a modulated signal of a single stream transmitted by using a multi-carrier transmission scheme such as the OFDM scheme. In Fig. 36, the horizontal axis indicates frequency and the vertical axis indicates time. Fig. 36 illustrates, as an example, symbols from carrier 1 to carrier 36. Fig. 36 also illustrates symbols from time 1 to time 11. The frame configuration illustrated in Fig. 36 is an example of the frame configuration of a modulated signal of a single stream transmitted by using a multi-carrier transmission scheme such as the OFDM scheme by the base station (AP), which is a communication partner of the terminal #p.

[0376] In Fig. 36, 3601 denotes a pilot symbol, 3602 denotes a data symbol, and 3603 denotes an other symbol. It is assumed that the pilot symbols 3601 are symbols used by the terminal #p to estimate channel variation, for example. It is assumed that the data symbols 3602 are symbols used by the base station or AP to transmit data to the terminal #p. It is assumed that the other symbols 3603 include, for example, symbols used by the terminal #p to perform signal detection, frequency offset estimation, frequency synchronization, and time synchronization, and / or control information symbols for demodulating the data symbols 3602 (information about the transmission method, modulation scheme, and error-correcting coding method of the data symbols 3602).

[0377] For example, the transmission apparatus of the base station in Fig. 1 or 24 may transmit a modulated signal of a single stream having the frame configuration in Fig. 36 to the terminal #p.

[0378] Fig. 37 is a diagram illustrating an example of the frame configuration of a modulated signal of a single stream transmitted by using a single-carrier transmission scheme. In Fig. 37, the elements similar to those in Fig. 10 are denoted by the same numerals. In Fig. 37, the horizontal axis indicates time, and Fig. 37 illustrates symbols from time t1 to t22. The frame configuration illustrated in Fig. 37 is an example of the frame configuration of a modulated signal of a single stream transmitted by using a single-carrier transmission scheme by the base station or AP, which is a communication partner of the terminal #p.

[0379] For example, the transmission apparatus of the base station in Fig. 1 or 24 may transmit a modulated signal of a single stream having the frame configuration in Fig. 37 to the terminal #p.

[0380] Also, for example, the transmission apparatus of the base station in Fig. 1 or 24 may transmit multiple modulated signals of multiple streams having the frame configurations in Figs. 8 and 9 to the terminal #p.

[0381] Furthermore, for example, the transmission apparatus of the base station in Fig. 1 or 24 may transmit multiple modulated signals of multiple streams having the frame configurations in Figs. 10 and 11 to the terminal #p.

[0382] Next, a description will be given of, using first to tenth examples, the reception capability in the reception apparatus of the terminal #p illustrated in Fig. 35, that is, the schemes supported by the reception apparatus, and the processing of the terminal #p and the processing of the base station (AP) based on the supported schemes.<First Example>

[0383] As the first example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 35 and the reception apparatus of the terminal #p supports the following. · For example, the reception of "communication scheme #A" described in the third embodiment is supported. · Thus, if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · Thus, in a case where the communication partner performs phase change when transmitting multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · Only the single-carrier scheme is supported. · Only the decoding of "error-correcting coding scheme #C" is supported as the error-correcting coding scheme.

[0384] Thus, the terminal #p having the configuration in Fig. 35 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0385] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example. Subsequently, the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0386] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes" (see Fig. 30), that the terminal #p supports "communication scheme #A".

[0387] Thus, the signal processor 155 of the base station determines not to transmit a modulated signal whose phase has been changed because the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30 is invalid and the communication scheme #A is supported, and outputs the control information 157 (see Fig. 22) including this information. This is because the communication scheme #A does not support the transmission and reception of multiple modulated signals for multiple streams.

[0388] In addition, the signal processor 155 of the base station determines not to transmit multiple modulated signals for multiple streams because the data 2901 about "support / not support reception for multiple streams" in Fig. 30 is invalid and the communication scheme #A is supported, and outputs the control signal 157 including this information. This is because the communication scheme #A does not support the transmission and reception of multiple modulated signals for multiple streams.

[0389] In addition, the signal processor 155 of the base station determines to use "error-correcting coding scheme #C" because the data 3003 about "supported error-correcting coding schemes" in Fig. 30 is invalid and the communication scheme #A is supported, and outputs the control signal 157 including this information. This is because the communication scheme #A supports "error-correcting coding scheme #C".

[0390] For example, as in Fig. 35, "communication scheme #A" is supported, and thus the base station or AP performs the above-described operations so as not to transmit multiple modulated signals for multiple streams. Thus, the base station (AP) appropriately transmits a modulated signal of "communication scheme #A", and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Second Example>

[0391] As the second example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 35 and the reception apparatus of the terminal #p supports the following. · For example, the reception of "communication scheme #B" described in the third embodiment is supported. · Since the reception apparatus has the configuration illustrated in Fig. 35, if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · Thus, in a case where the communication partner performs phase change when transmitting multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · The single-carrier scheme and the multi-carrier scheme such as the OFDM scheme are supported. · The decoding of "error-correcting coding scheme #C" and "error-correcting coding scheme #D" are supported as the error-correcting coding scheme.

[0392] Thus, the terminal #p having the configuration in Fig. 35 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0393] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example. Subsequently, the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0394] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #B".

[0395] Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that the terminal #p as a communication partner is unable to demodulate multiple modulated signals for multiple streams.

[0396] Thus, the signal processor 155 of the base station determines that the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30 is invalid and determines not to transmit a modulated signal whose phase has been changed, and outputs the control information 157 including this information. This is because the terminal #p does not support "reception for multiple streams".

[0397] In addition, on the basis of the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, the signal processor 155 of the base station outputs the control information 157 including information about whether the terminal #p as a communication partner supports the multi-carrier scheme and / or supports the single-carrier scheme.

[0398] In addition, on the basis of the data 3003 about "supported error-correcting coding schemes" in Fig. 30, the signal processor 155 of the base station outputs the control information 157 including information about whether the terminal #p as a communication partner supports "error-correcting coding scheme #C" and / or "error-correcting coding scheme #D".

[0399] Thus, the base station (AP) performs the above-described operations so as not to transmit multiple modulated signals for multiple streams, thereby being able to appropriately transmit a modulated signal of a single stream. Accordingly, the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Third Example>

[0400] As the third example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 35 and the reception apparatus of the terminal #p supports the following. · The reception of "communication scheme #A" and the reception of "communication scheme #B" described in the third embodiment are supported. · In both "communication scheme #A" and "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · Thus, in a case where the communication partner performs phase change when transmitting multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · In both "communication scheme #A" and "communication scheme #B", only the single-carrier scheme is supported. · Regarding the error-correcting coding scheme, the decoding of "error-correcting coding scheme #C" is supported as "communication scheme #A", and the decoding of "error-correcting coding scheme #C" and "error-correcting coding scheme #D" is supported as "communication scheme #B".

[0401] Thus, the terminal #p having the configuration in Fig. 35 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 30, for example.

[0402] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example. Subsequently, the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0403] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0404] Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that the terminal #p "does not support reception for multiple streams".

[0405] Thus, the signal processor 155 of the base station determines not to transmit a modulated signal whose phase has been changed because the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30 is invalid and the communication scheme #A is supported, and outputs the control information 157 including this information. This is because the terminal #p does not support the transmission and reception of multiple modulated signals for multiple streams.

[0406] Also, the signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, whether the terminal #p supports the single-carrier scheme or the multi-carrier scheme such as the OFDM scheme.

[0407] In addition, the signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p supports the decoding of "error-correcting coding scheme #C" and "error-correcting coding scheme #D".

[0408] Thus, the base station (AP) performs the above-described operations so as not to transmit multiple modulated signals for multiple streams, thereby being able to appropriately transmit a modulated signal of a single stream. Accordingly, the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Fourth Example>

[0409] As the fourth example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 35 and the reception apparatus of the terminal #p supports the following. · The reception of "communication scheme #A" and the reception of "communication scheme #B" described in the third embodiment are supported. · In both "communication scheme #A" and "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · Thus, in a case where the communication partner performs phase change when transmitting multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · The single-carrier scheme is supported as "communication scheme #A", and the single-carrier scheme and the multi-carrier scheme such as the OFDM scheme are supported as "communication scheme #B". · Regarding the error-correcting coding scheme, the decoding of "error-correcting coding scheme #C" is supported as "communication scheme #A", and the decoding of "error-correcting coding scheme #C" and "error-correcting coding scheme #D" is supported as "communication scheme #B".

[0410] Thus, the terminal #p having the configuration in Fig. 35 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0411] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0412] Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that the terminal #p "does not support reception for multiple streams".

[0413] Thus, the signal processor 155 of the base station determines not to transmit a modulated signal whose phase has been changed because the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30 is invalid and the communication scheme #A is supported, and outputs the control information 157 including this information. This is because the terminal #p does not support the transmission and reception of multiple modulated signals for multiple streams.

[0414] The signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, whether the terminal #p supports the single-carrier scheme or the multi-carrier scheme such as the OFDM scheme.

[0415] At this time, the data 3002 about "support / not support multi-carrier scheme" needs the configuration described below, for example.

[0416] The data 3002 about "support / not support multi-carrier scheme" is made up of 4 bits, and the 4 bits are represented by g0, g1, g2, and g3. At this time, the terminal #p sets g0, g1, g2, and g3 in the following manner in accordance with the reception capability of the terminal #p and transmits the data 3002 about "support / not support multi-carrier scheme".

[0417] In a case where the terminal #p supports the demodulation of the single-carrier scheme regarding "communication scheme #A", the terminal #p sets (g0, g1) = (0, 0).

[0418] In a case where the terminal #p supports the demodulation of the multi-carrier scheme such as OFDM regarding "communication scheme #A", the terminal #p sets (g0, g1) = (0, 1).

[0419] In a case where the terminal #p supports the demodulation of the single-carrier scheme and demodulation of the multi-carrier scheme such as OFDM regarding "communication scheme #A", the terminal #p sets (g0, g1) = (1, 1).

[0420] In a case where the terminal #p supports the demodulation of the single-carrier scheme regarding "communication scheme #B", the terminal #p sets (g2, g3) = (0, 0).

[0421] In a case where the terminal #p supports the demodulation of the multi-carrier scheme such as OFDM regarding "communication scheme #B", the terminal #p sets (g2, g3) = (0, 1).

[0422] In a case where the terminal #p supports the demodulation of the single-carrier scheme and demodulation of the multi-carrier scheme such as OFDM regarding "communication scheme #B", the terminal #p sets (g2, g3) = (1, 1).

[0423] In addition, the signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p supports the decoding of "error-correcting coding scheme #C" and "error-correcting coding scheme #D".

[0424] Thus, the base station (AP) performs the above-described operations so as not to transmit multiple modulated signals for multiple streams, thereby being able to appropriately transmit a modulated signal of a single stream. Accordingly, the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Fifth Example>

[0425] As the fifth example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 19 and the reception apparatus of the terminal #p supports the following, for example. · For example, the reception of "communication scheme #A" and "communication scheme #B" described in the third embodiment is supported. · In "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. In "communication scheme #A" and "communication scheme #B", if the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. · In a case where the communication partner performs phase change when transmitting modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. · Only the single-carrier scheme is supported. · Only the decoding of "error-correcting coding scheme #C" is supported as the error-correcting coding scheme.

[0426] Thus, the terminal #p having the configuration in Fig. 19 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0427] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example, and the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0428] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0429] In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits multiple modulated signals of multiple streams in "communication scheme #B", the terminal #p supports the reception of the modulated signals". Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits a modulated signal of a single stream in "communication scheme #A" and "communication scheme #B", the terminal #p supports the reception of the modulated signal".

[0430] Also, the signal processor 155 of the base station learns, from the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30, that the terminal #p "supports demodulation of phase changed signal".

[0431] The signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, that the terminal #p "supports only the single-carrier scheme".

[0432] The signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p "supports only the decoding of "error-correcting coding scheme #C"".

[0433] Thus, the base station (AP) appropriately generates and transmits a modulated signal that can be received by the terminal #p in consideration of a communication scheme supported by the terminal #p and a communication environment, and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Sixth Example>

[0434] As the sixth example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 19 and the reception apparatus of the terminal #p supports the following, for example. · For example, the reception of "communication scheme #A" and "communication scheme #B" described in the third embodiment is supported. · In "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. In "communication scheme #A" and "communication scheme #B", if the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. · In a case where the communication partner performs phase change when transmitting modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · Only the single-carrier scheme is supported. · The decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D" are supported as the error-correcting coding scheme.

[0435] Thus, the terminal #p having the configuration in Fig. 19 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0436] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example, and the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0437] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0438] In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits multiple modulated signals of multiple streams in "communication scheme #B", the terminal #p supports the reception of the modulated signals". Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits a modulated signal of a single stream in "communication scheme #A" and "communication scheme #B", the terminal #p supports the reception of the modulated signal".

[0439] Also, the signal processor 155 of the base station learns, from the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30, that the terminal #p "does not support demodulation of phase changed signal". Thus, the base station (AP) transmits multiple modulated signals of multiple streams to the terminal #p without performing phase change.

[0440] The signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, that the terminal #p "supports only the single-carrier scheme".

[0441] The signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p "supports the decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D"".

[0442] Thus, the base station (AP) appropriately generates and transmits a modulated signal that can be received by the terminal #p in consideration of a communication scheme supported by the terminal #p and a communication environment, and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Seventh Example>

[0443] As the seventh example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 19 and the reception apparatus of the terminal #p supports the following, for example. · For example, the reception of "communication scheme #A" and "communication scheme #B" described in the third embodiment is supported. · In "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. In "communication scheme #A" and "communication scheme #B", if the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. · The single-carrier scheme is supported as "communication scheme #A", and the single-carrier scheme and the multi-carrier scheme such as the OFDM scheme are supported as "communication scheme #B". However, it is assumed that, only in the case of the multi-carrier scheme such as the OFDM scheme in "communication scheme #B", "the communication partner is able to perform phase change when transmitting modulated signals of multiple streams". · In a case where the communication partner performs phase change when transmitting modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. · The decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D" are supported as the error-correcting coding scheme.

[0444] Thus, the terminal #p having the configuration in Fig. 19 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and the present embodiment, and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0445] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example, and the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0446] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0447] In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits multiple modulated signals of multiple streams in "communication scheme #B", the terminal #p supports the reception of the modulated signals". In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits a modulated signal of a single stream in "communication scheme #A" and "communication scheme #B", the terminal #p supports the reception of the modulated signal".

[0448] Also, the signal processor 155 of the base station learns, from the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30, that the terminal #p "does not support demodulation of phase changed signal". Thus, the base station (AP) transmits multiple modulated signals of multiple streams to the terminal #p without performing phase change. When the terminal #p obtains information "support demodulation of phase changed signal" from the data 2801 about "support / not support demodulation of phase changed signal" as described above, the terminal #p understands that it is only in "communication scheme #B".

[0449] The signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, that the terminal #p supports the single-carrier scheme as "communication scheme #A" and supports the single-carrier scheme and the multi-carrier scheme such as the OFDM scheme as "communication scheme #B". At this time, as described above, the terminal #p may preferably notify the base station or AP of the situation of supporting the single-carrier scheme and the multi-carrier scheme such as OFDM in "communication scheme #A" and supporting the single-carrier scheme and the multi-carrier scheme such as OFDM in "communication scheme #B".

[0450] The signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p "supports the decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D"".

[0451] Thus, the base station (AP) appropriately generates and transmits a modulated signal that can be received by the terminal #p in consideration of a communication scheme supported by the terminal #p and a communication environment, and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Eighth Example>

[0452] As the eighth example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 19 and the reception apparatus of the terminal #p supports the following, for example. · For example, the reception of "communication scheme #A" and "communication scheme #B" described in the third embodiment is supported. · In "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. In "communication scheme #A" and "communication scheme #B", if the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. · In the single-carrier scheme in "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. On the other hand, in the multi-carrier scheme such as OFDM in "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p does not support the reception of the modulated signals. · In the single-carrier scheme in "communication scheme #A", when the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. The reception of the multi-carrier scheme such as the OFDM scheme is not supported. · In a case where the communication partner performs phase change when transmitting modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. · The decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D" are supported as the error-correcting coding scheme.

[0453] Thus, the terminal #p having the configuration in Fig. 19 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0454] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example, and the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0455] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0456] In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the base station transmits multiple modulated signals of multiple streams in the single-carrier scheme of "communication scheme #B", the terminal #p supports the reception of the modulated signals". In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the base station transmits multiple modulated signals of multiple streams in the multi-carrier scheme such as OFDM of "communication scheme #B", the terminal #p does not support the reception of the modulated signals". In addition, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the base station transmits a modulated signal of a single stream in "communication scheme #A" and "communication scheme #B", the terminal #p supports the reception of the modulated signal".

[0457] At this time, the data 2901 about "support / not support reception for multiple streams" needs the data configuration described below, for example.

[0458] The data 2901 about "support / not support reception for multiple streams" is made up of 2 bits, and the 2 bits are represented by h0 and h1.

[0459] In a case where the terminal #p supports the demodulation of multiple modulated signals of multiple streams transmitted by the communication partner in the single-carrier scheme of "communication scheme #B", the terminal #p sets h0 = 1. If the terminal #p does not support the demodulation, the terminal #p sets h0 = 0.

[0460] In a case where the terminal #p supports the demodulation of multiple modulated signals of multiple streams transmitted by the communication partner in the multi-carrier scheme such as OFDM of "communication scheme #B", the terminal #p sets h1 = 1. If the terminal #p does not support the demodulation, the terminal #p sets h1 = 0.

[0461] The signal processor 155 of the base station learns, from the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30, that the terminal #p "supports demodulation of phase changed signal".

[0462] The signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, that the terminal #p "supports only the single-carrier scheme".

[0463] The signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p supports the decoding of "error-correcting coding scheme #C" and "error-correcting coding scheme #D".

[0464] Thus, the base station (AP) appropriately generates and transmits a modulated signal that can be received by the terminal #p in consideration of a communication scheme supported by the terminal #p and a communication environment, and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Ninth Example>

[0465] As the ninth example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 19 and the reception apparatus of the terminal #p supports the following, for example. · For example, the reception of "communication scheme #A" and "communication scheme #B" described in the third embodiment is supported. · In "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. In "communication scheme #A" and "communication scheme #B", if the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. · In "communication scheme #B", the base station (AP) as a communication partner is able to transmit multiple modulated signals for multiple streams in the single-carrier scheme and the multi-carrier scheme such as OFDM. However, the communication partner is able to perform phase change when transmitting multiple modulated signals of multiple streams only in the multi-carrier scheme such as the OFDM scheme of "communication scheme #B". In a case where the communication partner performs phase change when transmitting multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. · The decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D" are supported as the error-correcting coding scheme.

[0466] Thus, the terminal #p having the configuration in Fig. 19 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0467] At this time, the terminal #p generates the reception capability notification symbol 3702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example, and the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0468] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0469] The signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits multiple modulated signals of multiple streams in "communication scheme #B", the terminal #p supports the reception of the modulated signals". Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits a modulated signal of a single stream in "communication scheme #A" and "communication scheme #B", the terminal #p supports the reception of the modulated signal".

[0470] In addition, the signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, whether the terminal #p supports "single-carrier scheme", supports "multi-carrier scheme such as OFDM", or supports "both the single-carrier scheme and the multi-carrier scheme such as OFDM".

[0471] When the signal processor 155 of the base station learns that the terminal #p "supports the single-carrier scheme", the signal processor 155 of the base station interprets that the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30 is invalid and interprets that "demodulation of phase changed signal is not supported". This is because the base station as a communication partner does not support phase change at the time of the single-carrier scheme.

[0472] When the signal processor 155 of the base station learns that the terminal #p "supports the multi-carrier scheme such as OFDM" or "supports both the single-carrier scheme and the multi-carrier scheme such as OFDM", the signal processor 155 of the base station does not interpret that the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30 is invalid (i.e., interprets that the data 2801 is valid). The signal processor 155 of the base station obtains, from the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30, information indicating whether or not the terminal #p supports demodulation of phase changed signal in the multi-carrier scheme such as OFDM.

[0473] The signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p "supports the decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D"".

[0474] Thus, the base station (AP) appropriately generates and transmits a modulated signal that can be received by the terminal #p in consideration of a communication scheme supported by the terminal #p and a communication environment, and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.<Tenth Example>

[0475] As the tenth example, it is assumed that the reception apparatus of the terminal #p has the configuration illustrated in Fig. 19 and the reception apparatus of the terminal #p supports the following, for example. · For example, the reception of "communication scheme #A" and "communication scheme #B" described in the third embodiment is supported. · In "communication scheme #B", if the communication partner transmits multiple modulated signals of multiple streams, the terminal #p supports the reception of the modulated signals. In "communication scheme #A" and "communication scheme #B", if the communication partner transmits a modulated signal of a single stream, the terminal #p supports the reception of the modulated signal. · In "communication scheme #B", the base station or AP is able to transmit multiple modulated signals for multiple streams in the single-carrier scheme and the multi-carrier scheme such as OFDM. · In the single-carrier scheme, when the communication partner transmits modulated signals of multiple streams, whether or not to perform phase change can be set. In the multi-carrier scheme such as OFDM, when the communication partner transmits modulated signals of multiple streams, whether or not to perform phase change can be set. · The decoding of "error-correcting coding scheme #C" and the decoding of "error-correcting coding scheme #D" are supported as the error-correcting coding scheme.

[0476] Thus, the terminal #p having the configuration in Fig. 19 and supporting the above generates the reception capability notification symbol 2702 illustrated in Fig. 30 on the basis of the rules described in the third embodiment and transmits the reception capability notification symbol 2702 in accordance with the procedure in Fig. 27, for example.

[0477] At this time, the terminal #p generates the reception capability notification symbol 2702 illustrated in Fig. 30 in the transmission apparatus 3403 in Fig. 34, for example, and the transmission apparatus 3403 in Fig. 34 transmits the reception capability notification symbol 2702 illustrated in Fig. 30 in accordance with the procedure in Fig. 27.

[0478] The signal processor 155 of the base station (AP) in Fig. 22 obtains the baseband signal group 154 including the reception capability notification symbol 2702 transmitted by the terminal #p, through the reception antenna group 151 and the radio section group 153. Subsequently, the signal processor 155 of the base station (AP) in Fig. 22 extracts the data included in the reception capability notification symbol 2702 and learns, from the data 3001 about "supported schemes", that the terminal #p supports "communication scheme #A" and "communication scheme #B".

[0479] The signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits multiple modulated signals of multiple streams in "communication scheme #B", the terminal #p supports the reception of the modulated signals". Also, the signal processor 155 of the base station learns, from the data 2901 about "support / not support reception for multiple streams" in Fig. 30, that "if the communication partner transmits a modulated signal of a single stream in "communication scheme #A" and "communication scheme #B", the terminal #p supports the reception of the modulated signal".

[0480] In addition, the signal processor 155 of the base station learns, from the data 3002 about "support / not support multi-carrier scheme" in Fig. 30, whether the terminal #p supports "single-carrier scheme", supports "multi-carrier scheme such as OFDM", or supports "both the single-carrier scheme and the multi-carrier scheme such as OFDM".

[0481] Also, the signal processor 155 of the base station learns, from the data 2801 about "support / not support demodulation of phase changed signal" in Fig. 30, whether the terminal #p supports phase change.

[0482] At this time, the data 2801 about "support / not support demodulation of phase changed signal" needs the configuration described below, for example.

[0483] The data 2801 about "support / not support demodulation of phase changed signal" is made up of 2 bits, and the 2 bits are represented by k0 and k1.

[0484] When the communication partner transmits multiple modulated signals of multiple streams in the single-carrier scheme of "communication scheme #B" and performs phase change at that time, in a case where the terminal #p supports the demodulation of the modulated signals, the terminal #p sets k0 = 1. In a case where the terminal #p does not support the demodulation, the terminal #p sets k0 = 0.

[0485] When the communication partner transmits multiple modulated signals of multiple streams in the multi-carrier scheme such as OFDM of "communication scheme #B" and performs phase change at that time, in a case where the terminal #p supports the demodulation of the modulated signals, the terminal #p sets k1 = 1. In a case where the terminal #p does not support the demodulation, the terminal #p sets k1 = 0.

[0486] The signal processor 155 of the base station learns, from the data 3003 about "supported error-correcting coding schemes" in Fig. 30, that the terminal #p supports the decoding of "error-correcting coding scheme #C'" and "error-correcting coding scheme #D".

[0487] Thus, the base station (AP) appropriately generates and transmits a modulated signal that can be received by the terminal #p in consideration of a communication scheme supported by the terminal #p and a communication environment, and accordingly the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.

[0488] As described above, the base station (AP) obtains, from the terminal #p as a communication partner, information about a scheme in which the terminal #p supports demodulation, and decides the number of modulated signals, the communication method for the modulated signals, the signal processing method for the modulated signals, and so forth on the basis of the information, thereby being able to appropriately generate and transmit a modulated signal that can be received by the terminal #p. Accordingly, the data transmission efficiency in the system constituted by the base station (AP) and the terminal #p can be increased.

[0489] At this time, for example, when the reception capability notification symbol is made up of multiple pieces of data as in Fig. 30, the base station (AP) is able to easily determine whether the data included in the reception capability notification symbol is valid or invalid. Accordingly, there is an advantage of being able to quickly determine the scheme of modulated signals to be transmitted, the signal processing method, and so forth.

[0490] The base station (AP) transmits modulated signals to individual terminals #p by using a preferable transmission method on the basis of the details of information of the reception capability notification symbols transmitted by the individual terminals #p. Accordingly, the data transmission efficiency is increased.

[0491] The method for configuring the data of the reception capability notification symbol described in the present embodiment is an example, and the method for configuring the data of the reception capability notification symbol is not limited thereto. In addition, the transmission procedure and transmission timing for transmitting the reception capability notification symbol to the base station (AP) by the terminal #p according to the present embodiment are merely an example, and the transmission procedure and transmission timing are not limited thereto.

[0492] The reception capability communication symbol as described above is transmitted by each terminal. However, there may be a terminal that does not transmit the reception capability notification symbol. The base station (AP) receives the reception capability notification symbols transmitted by the individual terminals and generates modulated signals to be transmitted to the individual terminals. In particular, the base station (AP) described in this specification transmits the modulated signals to the individual terminals at identical frequencies (or using a certain frequency in common) and at identical times (or using a certain time in common). Accordingly, the data transmission efficiency in the system constituted by the base station (AP) and the terminals can be increased.(Sixth Embodiment)

[0493] The configuration in Fig. 26 has been described as an example of the configuration of the signal processor 206 in Fig. 2 in embodiments such as the first embodiment, the second embodiment, and the third embodiment. Hereinafter, a description will be given of an example of the operations of the phase changers 305A and 305B in Fig. 26.

[0494] As described in the third embodiment, the phase change value in the phase changer 305A is represented by Yp(i) and the phase change value in the phase changer 305B is represented by yp(i).

[0495] At this time, zp1(i) and zp2(i) are expressed by Expression (42). The period of phase change in the phase changer 305A is N, and the period of phase change in the phase changer 305B is N. However, it is assumed that N is an integer equal to or greater than 3, that is, an integer greater than 2, which is the number of streams to be transmitted or the number of modulated signals to be transmitted. At this time, the phase change value Yp(i) and the phase change value yp(i) are given as in the following Expression (43) and Expression (44), respectively. [Math. 43] Yp i = e j π × i N + Δ [Math. 44] yp i = e j − π × i N + Ω Here, Δ in Expression (43) and Ω in Expression (44) are real numbers. As an example, Δ and Ω are zero. However, Δ and Ω are not limited thereto. With such settings, the peak-to-average power ratio (PAPR) of the signal zp1(t) (or zp1(i)) and the PAPR of the signal zp2(t) (or zp2(i)) in Fig. 26 are equivalent to each other in the single-carrier scheme. Accordingly, the phase noise and the request criterion for linearity of a transmission power amplifier are equivalent among the radio sections 106_1 to 106_N in Fig. 1 and so forth, which is advantageous in that low power consumption can be easily realized and that a common configuration can be used for the radio sections. Also, there is a high possibility that a similar effect can be obtained also in the multi-carrier scheme such as OFDM.

[0496] Alternatively, the phase change values Yp(i) and yp(i) may be given as in the following Expression (45) and Expression (46), respectively. [Math. 45] Yp i = e j − π × i N + Δ [Math. 46] yp i = e j π × i N + Ω Also with Expression (45) and Expression (46), an effect similar to that described above can be obtained.

[0497] Alternatively, the phase change values Yp(i) and yp(i) may be given as in the following Expression (47) and Expression (48), respectively. [Math. 47] Yp i = e j k × π × i N + Δ [Math. 48] yp i = e j − k × π × i N + Ω Here, k is an integer except 0. For example, k may be 1, -1, 2, or -2. The value of k is not limited thereto. Also with Expression (47) and Expression (48), an effect similar to that described above can be obtained.(Seventh Embodiment)

[0498] In embodiments such as the first embodiment, the second embodiment, and the third embodiment, examples of the configuration of the signal processor 206 in Fig. 2 have been described. Hereinafter, an example of the configuration of the signal processor 206 in Fig. 2 different from the examples in Figs. 3, 4, and 26 will be described. Fig. 38 is a diagram illustrating still another example of the configuration of the signal processor 206 in Fig. 2. In Fig. 38, the elements that operate similarly to those in Fig. 3 are denoted by the same numerals, and the description thereof is omitted.

[0499] A phase changer 3801B receives the user #p mapped signal 301B represented by sp2(t) and the control signal 300. On the basis of the control signal 300, the phase changer 3801B performs phase change on the user #p mapped signal 301B, and outputs a phase-changed signal 3802B to the weight combiner 303.

[0500] When the weight combined signal 304A (for user #p), which is an output of the weight combiner 303, is represented by zp1(i) and the weight combined signal 304B (for user #p), which is an output of the weight combiner 303, is represented by zp2(i), zp1(i) and zp2(i) are expressed by the following Expression (49). [Math. 49] zp 1 i zp 2 i = a b c d 1 0 0 vp i sp 1 i sp 2 i = a b c d 1 0 0 e j × δp i sp 1 i sp 2 i Here, a, b, c, and d are defined as complex numbers, and thus may be real numbers. Also, i is a symbol number. Here, j is the imaginary unit, and δp(i) is a real number. In addition, zp1(i) and zp2(i) are transmitted from the transmission apparatus at identical times and identical frequencies (identical frequency bands).

[0501] For example, a phase change value vp(i) in the phase changer 3801B is set as in the following Expression (50). [Math. 50] vp i = e j 2 × π × i Np In Expression (50), j is the imaginary unit. In addition, Np is an integer equal to or greater than 2 and represents the period of phase change. If Np is set to an odd number equal to or greater than 3, there is a possibility that the data reception quality is improved. In addition, Np may preferably be set to be greater than 2, which is the number of streams (the number of modulated signals) to be transmitted for the user #p. However, Expression (50) is merely an example, and the phase change value set in the phase changer 3801B is not limited thereto.

[0502] Next, a configuration different from those in Figs. 3, 4, 26, and 38 will be described. Fig. 39 is a diagram illustrating still another example of the configuration of the signal processor 206 in Fig. 2. In Fig. 39, the elements that operate similarly to those in Figs. 3 and 38 are denoted by the same numerals, and the description thereof is omitted.

[0503] A phase changer 3801A receives the user #p mapped signal 301A represented by sp1(t) and the control signal 300. On the basis of the control signal 300, the phase changer 3801A performs phase change on the user #p mapped signal 301A, and outputs a phase-changed signal 3802A.

[0504] When the weight combined signal 304A (for user #p), which is an output of the weight combiner 303, is represented by zp1(i) and the weight combined signal 304B (for user #p), which is an output of the weight combiner 303, is represented by zp2(i), zp1(i) and zp2(i) are expressed by the following Expression (51). [Math. 51] zp 1 i zp 2 i = a b c d Vp i 0 0 νp i sp 1 i sp 2 i = a b c d e j × λp i 0 0 e j × δp i sp 1 i sp 2 i Here, a, b, c, and d are defined as complex numbers, and thus may be real numbers. Also, i is a symbol number. Here, j is the imaginary unit, and λp(i) is a real number. In addition, zp1(i) and zp2(i) are transmitted from the transmission apparatus at identical times (or using a certain time in common) and identical frequencies (identical frequency bands) (or using a certain frequency in common).

[0505] By carrying out the embodiment as above, particularly in an environment in which direct waves are dominant, when the base station transmits a modulated signal by using the above-described transmission method, a terminal as a communication partner is able to obtain high data reception quality.(Eighth Embodiment)

[0506] In embodiments such as the first embodiment, the second embodiment, the third embodiment, and the seventh embodiment, examples of the configuration of the signal processor 206 in Fig. 2 have been described. Hereinafter, a description will be given of an example of the operations of the phase changers 3801A and 3801B in Fig. 39.

[0507] As described in the seventh embodiment, the phase change value in the phase changer 3801A is represented by Vp(i), and the phase change value in the phase changer 3801B is represented by vp(i). At this time, zp1(i) and zp2(i) are expressed by Expression (51). The period of phase change in the phase changer 3801A is N, and the period of phase change in the phase changer 3801B is N. However, it is assumed that N is an integer equal to or greater than 3, that is, an integer greater than 2, which is the number of streams to be transmitted or the number of modulated signals to be transmitted. At this time, the phase change value Vp(i) and the phase change value vp(i) are given as in the following Expression (52) and Expression (53), respectively. [Math. 52] Vp i = e j π × i N + Δ [Math. 53] νp i = e j − π × i N + Ω Here, Δ in Expression (52) and Ω in Expression (53) are real numbers. As an example, Δ and Ω are zero. However, Δ and Ω are not limited thereto. With such settings, the peak-to-average power ratio (PAPR) of the signal zp1(t) (or zp1(i)) and the PAPR of the signal zp2(t) (or zp2(i)) in Fig. 39 are equivalent to each other in the single-carrier scheme. Accordingly, the phase noise and the request criterion for linearity of a transmission power amplifier are equivalent among the radio sections 106_1 to 106_N in Fig. 1 and so forth, which is advantageous in that low power consumption can be easily realized and that a common configuration can be used for the radio sections. Also, there is a high possibility that a similar effect can be obtained also in the multi-carrier scheme such as OFDM.

[0508] Alternatively, the phase change values Vp(i) and vp(i) may be given as in the following Expression (54) and Expression (55), respectively. [Math. 54] Vp i = e j − π × i N + Δ [Math. 55] νp i = e j π × i N + Ω Also with Expression (54) and Expression (55), an effect similar to that described above can be obtained.

[0509] Alternatively, the phase change values Vp(i) and vp(i) may be given as in the following Expression (56) and Expression (57), respectively. [Math. 56] Vp i = e j k × π × i N + Δ [Math. 57] νp i = e j − k × π × i N + Ω Here, k is an integer except 0. For example, k may be 1, -1, 2, or -2. The value of k is not limited thereto. Also with Expression (56) and Expression (57), an effect similar to that described above can be obtained.(Ninth Embodiment)

[0510] In the present embodiment, the arrangement of phase changers will be described. In Figs. 3 and 26 described above, a configuration in which phase changers are arranged on the output side of the weight combiner 303 (hereinafter referred to as downstream of the weight combiner 303 as appropriate) is illustrated. In Figs. 38 and 39, a configuration in which phase changers are arranged on the input side of the weight combiner 303 (hereinafter referred to as upstream of the weight combiner 303 as appropriate) is illustrated. The phase changers may be arranged both upstream and downstream of the weight combiner 303. In the present embodiment, a description will be given of an example in which phase changes are arranged upstream and downstream of the weight combiner 303.

[0511] Fig. 40 is a diagram illustrating a first example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 40, the elements similar to those in Figs. 3, 26, 38, and 39 are denoted by the same numerals, and the description thereof is omitted.

[0512] As illustrated in Fig. 40, the phase changer 3801A is arranged upstream of the weight combiner 303, on the side where the user #p mapped signal 301A of sp1(t) is input (i.e., the upper stage on the page). The phase changer 3801B is arranged upstream of the weight combiner 303, on the side where the user #p mapped signal 301B of sp2(t) is input (i.e., the lower stage). The phase changer 305A is arranged downstream of the weight combiner 303, on the side where the user #p weighted signal 304A is output (i.e., the upper stage). The phase changer 305B is arranged downstream of the weight combiner 303, on the side where the user #p weighted signal 304B is output (i.e., the lower stage).

[0513] As illustrated in Fig. 40, the phase changer 3801A receives the user #p mapped signal 301A of sp1(t) and the control signal 300. On the basis of information about a phase change method included in the control signal 300, for example, the phase changer 3801A performs phase change on the user #p mapped signal 301A, and outputs the phase-changed signal 3802A.

[0514] Likewise, the phase changer 3801B receives the user #p mapped signal 301B of sp2(t) and the control signal 300. On the basis of information about a phase change method included in the control signal 300, for example, the phase changer 3801B performs phase change on the user #p mapped signal 301B, and outputs the phase-changed signal 3802B.

[0515] The phase-changed signal 306A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39, and the phase-changed signal 306B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0516] Fig. 41 is a diagram illustrating a second example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 41, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0517] In Fig. 41, unlike in Fig. 40, only the phase changer 305B is arranged downstream of the weight combiner 303. The weighted signal 304A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the phase-changed signal 306B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0518] Fig. 42 is a diagram illustrating a third example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 42, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0519] In Fig. 42, unlike in Fig. 41, the phase changer 305A exists downstream of the weight combiner 303 in the upper stage. The phase-changed signal 306A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the weighted signal 304B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0520] Fig. 43 is a diagram illustrating a fourth example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 43, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0521] In Fig. 43, unlike in Fig. 40, only the phase changer 3801B exists upstream of the weight combiner 303. The phase-changed signal 306A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the phase-changed signal 306B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0522] Fig. 44 is a diagram illustrating a fifth example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 44, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0523] In Fig. 44, unlike in Fig. 43, the phase changer 3801A exists upstream of the weight combiner 303 in the upper stage. The phase-changed signal 306A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the phase-changed signal 306B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0524] Fig. 45 is a diagram illustrating a sixth example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 45, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0525] In Fig. 45, the phase changer 3801B is arranged upstream of the weight combiner 303 in the lower stage, and the phase changer 305B is arranged downstream of the weight combiner 303 in the lower stage. The weighted signal 304A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the phase-changed signal 306B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0526] Fig. 46 is a diagram illustrating a seventh example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 46, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0527] In Fig. 46, the phase changer 3801B is arranged upstream of the weight combiner 303 in the lower stage, and the phase changer 305A is arranged downstream of the weight combiner 303 in the upper stage. The phase-changed signal 306A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the weighted signal 304B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0528] Fig. 47 is a diagram illustrating an eighth example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 47, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0529] In Fig. 47, the phase changer 3801A is arranged upstream of the weight combiner 303 in the upper stage, and the phase changer 305B is arranged downstream of the weight combiner 303 in the lower stage. The weighted signal 304A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the phase-changed signal 306B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0530] Fig. 48 is a diagram illustrating a ninth example in which phase changers are arranged upstream and downstream of the weight combiner 303. In Fig. 48, the elements similar to those in Figs. 3, 26, 38, 39, and 40 are denoted by the same numerals, and the description thereof is omitted.

[0531] In Fig. 48, the phase changer 3801A is arranged upstream of the weight combiner 303 in the upper stage, and the phase changer 305A is arranged downstream of the weight combiner 303 in the upper stage. The phase-changed signal 306A is input to the inserter 307A illustrated in Figs. 3, 26, 38, and 39. Also, the weighted signal 304B is input to the inserter 307B illustrated in Figs. 3, 26, 38, and 39.

[0532] Also with the above-described configurations, individual embodiments in this specification can be carried out, and the effects described in the individual embodiments can be obtained. The phase change methods for the phase changers 3801A, 3801B, 305A, and 305B in Figs. 40, 41, 42, 43, 44, 45, 46, 47, and 48 are set by the control signal 300, for example.(Tenth Embodiment)

[0533] Figs. 3, 26, 38, and 39 illustrate a configuration including the phase changer 309B as the configuration after the inserter 307A (i.e., on the output side of the inserter 307A) and after the inserter 307B (i.e., on the output side of the inserter 307B). In the present embodiment, a description will be given of an example configuration different from this configuration. The configurations illustrated in Figs. 40 to 48 may be used as the configuration before the inserter 307A and before the inserter 307B.

[0534] Fig. 49 is a diagram illustrating a first example configuration on the output side of the inserter. In Fig. 49, the elements similar to those in Figs. 3, 26, 38, 39, and so forth are denoted by the same numerals, and the description thereof is omitted.

[0535] A Cyclic Delay Diversity (CDD) section 4909A receives the baseband signal 308A and the control signal 300. On the basis of the control signal 300, the CDD section 4909A performs CDD processing on the baseband signal 308A, and outputs a CDD-processed baseband signal 4910A. CDD may also be called Cyclic Shift Diversity (CSD).

[0536] The CDD-processed baseband signal 4910A in Fig. 49 corresponds to the signal denoted by 207_A in Fig. 2, and the baseband signal 308B corresponds to the signal denoted by 207_B in Fig. 2.

[0537] Fig. 50 is a diagram illustrating a second example configuration on the output side of the inserter. In Fig. 50, the elements similar to those in Figs. 3, 26, 38, 39, and so forth are denoted by the same numerals, and the description thereof is omitted.

[0538] A CDD section 4909B receives the baseband signal 308B and the control signal 300. On the basis of the control signal 300, the CDD section 4909B performs CDD processing on the baseband signal 308B, and outputs a CDD-processed baseband signal 4910B.

[0539] The baseband signal 308A in Fig. 50 corresponds to the signal denoted by 207_A in Fig. 2, and the CDD-processed baseband signal 4910B corresponds to the signal denoted by 207B in Fig. 2.

[0540] Fig. 51 is a diagram illustrating a third example configuration on the output side of the inserter. In Fig. 51, the elements similar to those in Figs. 3, 26, 38, 39, 49, and 50 are denoted by the same numerals, and the description thereof is omitted. The example configuration illustrated in Fig. 51 is an example configuration in which both the CDD section 4909A illustrated in Fig. 49 and the CDD section 4909B illustrated in Fig. 50 are arranged.

[0541] The CDD-processed baseband signal 4910A in Fig. 51 corresponds to the signal denoted by 207_A in Fig. 2, and the CDD-processed baseband signal 4910B corresponds to the signal denoted by 207B in Fig. 2.

[0542] Figs. 49, 50, and 51 illustrate example configurations in which the CDD section is arranged on the output side of the inserter. Alternatively, a phase changer may be arranged on the output side of the inserter, as illustrated in Figs. 3, 26, and 38. The position of the phase changer may be different from that in Figs. 3, 26, and 38. Hereinafter, the arrangement of a phase changer will be described.

[0543] Fig. 52 is a diagram illustrating a fourth example configuration on the output side of the inserter. In Fig. 52, the elements similar to those in Figs. 3, 26, 38, 39, and so forth are denoted by the same numerals, and the description thereof is omitted.

[0544] A phase changer 309A receives the baseband signal 308A and the control signal 300. On the basis of the control signal 300, the phase changer 309A performs phase change processing on the baseband signal 308A, and outputs a phase-changed baseband signal 310A.

[0545] The phase-changed baseband signal 310A in Fig. 52 corresponds to the signal denoted by 207_A in Fig. 2, and the baseband signal 308B corresponds to the signal denoted by 207_B in Fig. 2.

[0546] Fig. 53 is a diagram illustrating a fifth example configuration on the output side of the inserter. In Fig. 53, the elements similar to those in Figs. 3, 26, 38, 39, 52, and so forth are denoted by the same numerals, and the description thereof is omitted.

[0547] The phase-changed baseband signal 310A in Fig. 53 corresponds to the signal denoted by 207_A in Fig. 2, and the phase-changed baseband signal 310B corresponds to the signal denoted by 207_B in Fig. 2.

[0548] Fig. 54 is a diagram illustrating a sixth example configuration on the output side of the inserter. In Fig. 54, the elements similar to those in Figs. 3, 26, 38, 39, 52, and so forth are denoted by the same numerals, and the description thereof is omitted.

[0549] The baseband signal 308A in Fig. 54 corresponds to the signal denoted by 207_A in Fig. 2, and the baseband signal 308B corresponds to the signal denoted by 207_B in Fig. 2.

[0550] Also with the above-described configurations, individual embodiments in this specification can be carried out, and the effects described in the individual embodiments can be obtained.[Regarding CDD (CSD)]

[0551] In the first embodiment, the ninth embodiment, and so forth, CDD (CSD) is described. In Figs. 49, 50, and 51, the CDD sections 4909A and 4909B are illustrated. In addition, in Figs. 3, 26, 38, 39, 52, 53, and 54, the phase changers 309A and 309B are illustrated.

[0552] Hereinafter, a supplemental description will be given of specific processing of CDD (CSD) and phase change.

[0553] Fig. 55 is a diagram for describing CDD (CSD). In Fig. 55, 5502_1 to 5502_M denote the sections that perform processing similar to the processing performed by the CDD sections 4909A and 4909B in Figs. 49, 50, and 51. In Fig. 55, a modulated signal 5501 that is to be subjected to cyclic delay is represented by X[n]. It is assumed that X[n] is made up of N samples (N is an integer equal to or greater than 2), and thus n is an integer from 0 to N-1.

[0554] The cyclic delay section 5502_1 receives the modulated signal 5501, performs cyclic delay processing, and outputs a cyclic-delay-processed signal 5503_1. When the cyclic-delay-processed signal 5503_1 is represented by X1[n], X1[n] is given as the following Expression (58). [Math. 58] X 1 n = X n − δ 1 mod N Here, δ1 is a cyclic delay amount (δ1 is a real number). In addition, mod represents modulo, and "A mod B" means "a remainder obtained by dividing A by B". That is, X1[n] is a signal obtained by delaying the modulated signal X[n] having N samples by δ1 and moving the portion in the range from (N-δ1) to N of the modulated signal X[n] to the top. In the description given above, a discrete signal is described as an example, but similar processing may be performed on a continuous signal. The same applies to an output signal of cyclic delay in the following description.

[0555] The cyclic delay section 5502_M receives the modulated signal 5501, performs cyclic delay processing, and outputs a cyclic-delay-processed signal 5503_M. When the cyclic-delay-processed signal 5503_M is represented by XM[n], X[n] is given as the following Expression (59). [Math. 59] XM n = X n − δM mod N Here, δM is a cyclic delay amount (δM is an integer).

[0556] Thus, a cyclic delay section 5502_i (i is in integer from 1 to M (M is an integer equal to or greater than 1) receives the modulated signal 5501, performs cyclic delay processing, and outputs a cyclic-delay-processed signal 5503_i. When the cyclic-delay-processed signal 5503_i is represented by Xi[n], Xi[n] is given as the following Expression (60). [Math. 60] Xi n = X n − δi mod N Here, δi is an amount of cyclic delay (δi is an integer).

[0557] The cyclic-delay-processed signal 5503_i is transmitted from an antenna i (thus, the cyclic-delay-processed signal 5503_1, ···, and the cyclic-delay-processed signal 5503_M are transmitted from different antennas).

[0558] Accordingly, a diversity effect of cyclic delay can be obtained (in particular, a negative influence of a delayed wave can be reduced), and the data reception quality can be improved in the reception apparatus.

[0559] For example, the phase changers 309A and 309B in Figs. 3, 26, 38, 39, 52, 53, and 54 may be replaced with the cyclic delay sections illustrated in Fig. 55, and the operations of the phase changers 309A and 309B may be the same as the operations of the cyclic delay sections.

[0560] Thus, a cyclic delay amount δ (δ is an integer) is given in the phase changers 309A and 309B in Figs. 3, 26, 38, 39, 52, 53, and 54, and the input signal of the phase changers 309A and 309B is represented by Y[n]. When the output signal of the phase changer 209B is represented by Z[n], Z[n] is given as Expression (61). [Math. 61] Z n = Y n − δ mod N Here, Y[n] is made up of N symbols (N is an integer equal to or greater than 2). Thus, n is an integer from 0 to N-1.

[0561] Next, a description will be given of the relationship between a cyclic delay amount and phase change. For example, the case of applying CDD (CSD) to OFDM will be discussed. It is assumed that the carrier of the lowest frequency is "carrier 1", and "carrier 2", "carrier 3", and "carrier 4" follow in this order.

[0562] For example, it is assumed that a cyclic delay amount µ is given in the phase changers 309A and 309B in Figs. 3, 26, 38, 39, 52, 53, and 54. Then, a phase change value Ω[i] in "carrier i" is expressed by the following Expression (62). [Math. 62] Ω i = e j × μ × i Here, µ is a value that can be obtained from a cyclic delay amount, a fast Fourier transform (FFT) size, and so forth.

[0563] When "carrier i" before phase change (before cyclic delay processing) and the baseband signal at time t are represented by v'[i][t], "carrier i" after phase change and the signal v[i][t] at time t can be expressed by v[i][t] = Ω[i]×v'[i][t].(Eleventh Embodiment)

[0564] In this specification, the example configuration illustrated in Fig. 2 has been described as an example of the configuration of the user #p signal processor 102_p in Fig. 1. In the present embodiment, a description will be given of a configuration different from that in Fig. 2 as the configuration of the user #p signal processor 102_p in Fig. 1.

[0565] Fig. 56 is a diagram illustrating an example of the configuration of the user #p signal processor different from that in Fig. 2. In Fig. 56, the elements similar to those in Fig. 2 are denoted by the same reference numerals, and the description thereof is omitted. In Fig. 56, the point different from Fig. 2 is that multiple error-correcting encoders and multiple mappers exist.

[0566] Specifically, in Fig. 56, two error-correcting encoders (error-correcting encoders 202_1 and 202_2) exist. Fig. 2 illustrates a configuration including one error-correcting encoder 202 and Fig. 56 illustrates a configuration including two error-correcting encoders (202_1 and 202_2), but the number of error-correcting encoders is not limited thereto. For example, in a case where there are three or more error-correcting encoders, the mapper 204 (204_1 and 204_2) performs mapping by using the data output from each error-correcting encoder.

[0567] In Fig. 56, the error-correcting encoder 202_1 receives first data 201_1 and the control signal 200. On the basis of information about an error-correcting coding method included in the control signal 200, the error-correcting encoder 202_1 performs error-correcting coding on the first data 201_1, and outputs coded data 203_1.

[0568] The mapper 204_1 receives the coded data 203_1 and the control signal 200. On the basis of information about a modulation scheme included in the control signal 200, the mapper 204_1 performs mapping on the coded data 203_1, and outputs the mapped signal 205_1.

[0569] The error-correcting encoder 202_2 receives second data 201_2 and the control signal 200. On the basis of information about an error-correcting coding method included in the control signal 200, the error-correcting encoder 202_2 performs error-correcting coding on the second data 201_2, and outputs coded data 203_2.

[0570] The mapper 204_2 receives the coded data 203_2 and the control signal 200. On the basis of information about a modulation scheme included in the control signal 200, the mapper 204_2 performs mapping on the coded data 203_2, and outputs the mapped signal 205_2.

[0571] In the each embodiment described in this specification, even if the configuration of the user #p signal processor 102_p illustrated in Fig. 2 is replaced with the configuration illustrated in Fig. 56, the embodiment can be carried out similarly and a similar effect can be obtained.

[0572] In addition, for example, the case of generating a signal with the configuration in Fig. 2 and the case of generating a signal with the configuration in Fig. 56 may be switched in the user #p signal processor 102_p.(Twelfth Embodiment)

[0573] In the above embodiments, a description has been given of the configurations in which a mapper is included in the user #p signal processor, with reference to Figs. 2, 31, 32, and 56, for example. In the present embodiment, a description will be given of a method for realizing robust communication in the mapper, by using the following first to sixth examples.<First Example>

[0574] Fig. 57 is a diagram illustrating the first example of the operation of a mapper 5702. The operation of the mapper 5702 illustrated in Fig. 57 corresponds to an example of the operation of the mapper 204 in the user #p signal processor 102_p illustrated in Fig. 2. In addition, a control signal 5700 corresponds to the control signal 200 in Fig. 2, coded data 5701 corresponds to the user #p data 203 in Fig. 2, a mapped signal 5703A corresponds to the mapped signal 205_1 in Fig. 2, and a mapped signal 5703B corresponds to the mapped signal 205_2 in Fig. 2.

[0575] The mapper 5702 receives the coded data 5701 and the control signal 5700. In a case where a robust transmission method is designated by the control signal 5700, the mapper 5702 performs the mapping described below, and outputs the mapped signals 5703A and 5703B (for the user #p).

[0576] It is assumed that bit c0(k), bit c1(k), bit c2(k), and bit c3(k) are input as the coded data 5701 to the mapper 5702. Here, k is an integer equal to or greater than 0.

[0577] It is assumed that the mapper 5702 performs QPSK modulation on c0(k) and c1(k) to obtain a mapped signal a(k). In addition, it is assumed that the mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain a mapped signal b(k).

[0578] Also, it is assumed that the mapper 5702 performs QPSK modulation on c0(k) and c1(k) to obtain a mapped signal a'(k). In addition, it is assumed that the mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain a mapped signal b'(k).

[0579] The mapped signal 5703A with a symbol number i = 2k is represented by sp1(i = 2k), and the mapped signal 5703B with a symbol number i = 2k is represented by sp2(i = 2k). Also, the mapped signal 5703A with a symbol number i = 2k+1 is represented by sp1(i = 2k+1), and the mapped signal 5703B with a symbol number i = 2k+1 is represented by sp2(i = 2k+1).

[0580] In addition, sp1(i = 2k), which is the mapped signal 5703A with a symbol number i = 2k, is represented by a(k), and sp2(i = 2k), which is the mapped signal 5703B with a symbol number i = 2k, is represented by b(k). Also, sp1(i = 2k+1), which is the mapped signal 5703A with a symbol number i = 2k+1, is represented by b'(k), and sp2(i = 2k+1), which is the mapped signal 5703B with a symbol number i = 2k+1, is represented by a'(k).

[0581] That is, the mapper 5702 performs QPSK modulation on c0(k) and c1(k) to generate a(k) as the mapped signal 5703A (sp1(i = 2k)) with a symbol number i = 2k. Also, the mapper 5702 performs QPSK modulation on c0(k) and c1(k) to generate a'(k) as the mapped signal 5703B (sp2(i = 2k+1)) with a symbol number i = 2k+1.

[0582] Also, the mapper 5702 performs QPSK modulation on c2(k) and c3(k) to generate b(k) as the mapped signal 5703B (sp2(i = 2k)) with a symbol number i = 2k. Also, the mapper 5702 performs QPSK modulation on c2(k) and c3(k) to generate a'(k) as the mapped signal 5703A (sp1(i = 2k+1)) with a symbol number i = 2k+1.

[0583] In this way, the mapper 5702 outputs two mapped signals (for example, a(k) and a'(k)) with different symbol numbers i and different streams (i.e., sp1 or sp2) by using identical bits (for example, c0(k) and c1(k)).

[0584] As described above, a(k) and a'(k) are generated from the identical bits c0(k) and c1(k) and output from the mapper 5702 as different symbol numbers and different streams. Likewise, b(k) and b'(k) are generated from the identical bits c2(k) and c3(k) and output from the mapper 5702 as different symbol numbers and different streams.

[0585] The mapper 5702 may change signal point arrangement when generating a(k) and a'(k). Also, the mapper 5702 may change signal point arrangement when generating b(k) and b'(k). Hereinafter, a description will be given of an example of signal point arrangement of QPSK modulation, an example of the relationship between a(k) and a'(k), and an example of the relationship between b(k) and b'(k).[Example of Signal Point Arrangement of QPSK Modulation]

[0586] Fig. 58 is a diagram illustrating a first example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. Fig. 58 illustrates the relationship among signal points for the values of bit x0 and bit x1.

[0587] When bit [x0, x1] = [0, 0] (x0 is 0, x1 is 0), an in-phase component I = z and a quadrature component Q = z are set. This is a signal point 5801. Here, z is a real number greater than 0. When bit [x0, x1] = [0, 1] (x0 is 0, x1 is 1), an in-phase component I = -z and a quadrature component Q = z are set. This is a signal point 5802. When bit [x0, x1] = [1, 0] (x0 is 1, x1 is 0), an in-phase component I = z and a quadrature component Q = -z are set. This is a signal point 5803. When bit [x0, x1] = [1, 1] (x0 is 1, x1 is 1), an in-phase component I = -z and a quadrature component Q = -z are set. This is a signal point 5804.

[0588] Fig. 59 is a diagram illustrating a second example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. Fig. 59 illustrates the relationship among signal points for the values of bit x0 and bit x1. Note that the relationship of signal points with respect to the values of bit x0 and bit x1 in Fig. 58 is different from the relationship of signal points with respect to the values of bit x0 and bit x1 in Fig. 59.

[0589] When bit [x0, x1] = [0, 0] (x0 is 0, x1 is 0), an in-phase component I = z and a quadrature component Q = -z are set. This is a signal point 5903. Here, z is a real number greater than 0. When bit [x0, x1] = [0, 1] (x0 is 0, x1 is 1), an in-phase component I = -z and a quadrature component Q = -z are set. This is a signal point 5904. When bit [x0, x1] = [1, 0] (x0 is 1, x1 is 0), an in-phase component I = z and a quadrature component Q = z are set. This is a signal point 5901. When bit [x0, x1] = [1, 1] (x0 is 1, x1 is 1), an in-phase component I = -z and a quadrature component Q = z are set. This is a signal point 5902.

[0590] Fig. 60 is a diagram illustrating a third example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. Fig. 60 illustrates the relationship among signal points for the values of bit x0 and bit x1. Note that the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 60 is different from the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 58 and the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 59.

[0591] When bit [x0, x1] = [0, 0] (x0 is 0, x1 is 0), an in-phase component I = -z and a quadrature component Q = z are set. This is a signal point 6002. Here, z is a real number greater than 0. When bit [x0, x1] = [0, 1] (x0 is 0, x1 is 1), an in-phase component I = z and a quadrature component Q = z are set. This is a signal point 6001. When bit [x0, x1] = [1, 0] (x0 is 1, x1 is 0), an in-phase component I = -z and a quadrature component Q = -z are set. This is a signal point 6004. When bit [x0, x1] = [1, 1] (x0 is 1, x1 is 1), an in-phase component I = z and a quadrature component Q = -z are set. This is a signal point 6003.

[0592] Fig. 61 is a diagram illustrating a fourth example of signal point arrangement of QPSK modulation on the in-phase I quadrature Q plane. Fig. 58 illustrates the relationship among signal points for the values of bit x0 and bit x1. Note that the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 61 is different from the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 58, the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 59, and the "relationship of signal points with respect to the values of bit x0 and bit x1" in Fig. 60.

[0593] When bit [x0, x1] = [0, 0] (x0 is 0, x1 is 0), an in-phase component I = -z and a quadrature component Q = -z are set. This is a signal point 6104. Here, z is a real number greater than 0. When bit [x0, x1] = [0, 1] (x0 is 0, x1 is 1), an in-phase component I = z and a quadrature component Q = -z are set. This is a signal point 6103. When bit [x0, x1] = [1, 0] (x0 is 1, x1 is 0), an in-phase component I = -z and a quadrature component Q = z are set. This is a signal point 6102. When bit [x0, x1] = [1, 1] (x0 is 1, x1 is 1), an in-phase component I = z and a quadrature component Q = z are set. This is a signal point 6101.[Example of Relationship between a(k) and a'(k)]

[0594] For example, it is assumed that the mapper 5702 uses the signal point arrangement in Fig. 58 to generate a(k). In a case where c0(k) = 0 and c1(k) = 0, the mapper 5702 maps c0(k) = 0 and c1(k) = 0 to the signal point 5801 on the basis of the signal point arrangement in Fig. 58. That is, in this case, the signal point 5801 corresponds to a(k).

[0595] Settings are made so that the mapper 5702 uses any of the signal point arrangement in Fig. 58, the signal point arrangement in Fig. 59, the signal point arrangement in Fig. 60, and the signal point arrangement in Fig. 61 to generate a'(k).

[0596] <1> In a case where settings are made so that the signal point arrangement in Fig. 58 is used to generate a'(k), c0(k) = 0 and c1(k) = 0, and thus the mapper 5702 maps c0(k) = 0 and c1(k) = 0 to the signal point 5801 on the basis of the signal point arrangement in Fig. 58. That is, in this case, the signal point 5801 corresponds to a'(k). <2> In a case where settings are made so that the signal point arrangement in Fig. 59 is used to generate a'(k), c0(k) = 0 and c1(k) = 0, and thus the mapper 5702 maps c0(k) = 0 and c1(k) = 0 to the signal point 5903 on the basis of the signal point arrangement in Fig. 59. That is, in this case, the signal point 5903 corresponds to a'(k). <3> In a case where settings are made so that the signal point arrangement in Fig. 60 is used to generate a'(k), c0(k) = 0 and c1(k) = 0, and thus the mapper 5702 maps c0(k) = 0 and c1(k) = 0 to the signal point 6002 on the basis of the signal point arrangement in Fig. 60. That is, in this case, the signal point 6002 corresponds to a'(k). <4> In a case where settings are made so that the signal point arrangement in Fig. 61 is used to generate a'(k), c0(k) = 0 and c1(k) = 0, and thus the mapper 5702 maps c0(k) = 0 and c1(k) = 0 to the signal point 6104 on the basis of the signal point arrangement in Fig. 61. That is, in this case, the signal point 6104 corresponds to a'(k).

[0597] As described above, the relationship between "the bits and signal point arrangement for generating a(k)" and the relationship between "the bits and signal point arrangement for generating a'(k)" may be identical to or different from each other.

[0598] As an "example of a case where the relationships are identical", a description has been given of an example of using Fig. 58 to generate a(k) and using Fig. 58 to generate a'(k).

[0599] As an "example of a case where the relationships are different", a description has been given of an example of using Fig. 58 to generate a(k) and using Fig. 59 to generate a'(k), an example of using Fig. 58 to generate a(k) and using Fig. 60 to generate a'(k), and an example of using Fig. 58 to generate a(k) and using Fig. 61 to generate a'(k).

[0600] For another example, the modulation scheme for generating a(k) may be different from the modulation scheme for generating a'(k). Alternatively, the signal point arrangement on the in-phase I quadrature Q plane for generating a(k) may be different from the signal point arrangement on the in-phase I quadrature Q plane for generating a'(k).

[0601] For example, QPSK may be used as described above as the modulation scheme for generating a(k), and a modulation scheme of signal point arrangement different from QPSK may be used as the modulation scheme for generating a'(k). In addition, the signal point arrangement in Fig. 58 may be used as the signal point arrangement on the in-phase I quadrature Q plane for generating a(k), and a signal point arrangement different from that in Fig. 58 may be used as the signal point arrangement on the in-phase I quadrature Q plane for generating a'(k).

[0602] A state where the signal point arrangement on the in-phase I quadrature Q plane is different means, for example, when the coordinates of the four signal points on the in-phase I quadrature Q plane for generating a(k) is those in Fig. 58, at least one of the four signal points on the in-phase I quadrature Q plane for generating a'(k) does not overlap any of the four signal points in Fig. 58.[Example of Relationship between b(k) and b'(k)]

[0603] For example, it is assumed that the mapper 5702 uses the signal point arrangement in Fig. 58 to generate b(k). In a case where c2(k) = 0 and c3(k) = 0, the mapper 5702 maps c2(k) = 0 and c3(k) = 0 to the signal point 5801 on the basis of the signal point arrangement in Fig. 58. That is, in this case, the signal point 5801 corresponds to b(k).

[0604] Settings are made so that the mapper 5702 uses any of the signal point arrangement in Fig. 58, the signal point arrangement in Fig. 59, the signal point arrangement in Fig. 60, and the signal point arrangement in Fig. 61 to generate b'(k).

[0605] <5> In a case where settings are made so that the signal point arrangement in Fig. 58 is used to generate b'(k), c2(k) = 0 and c3(k) = 0, and thus the mapper 5702 maps c2(k) = 0 and c3(k) = 0 to the signal point 5801 on the basis of the signal point arrangement in Fig. 58. That is, in this case, the signal point 5801 corresponds to b'(k). <6> In a case where settings are made so that the signal point arrangement in Fig. 59 is used to generate b'(k), c2(k) = 0 and c3(k) = 0, and thus the mapper 5702 maps c2(k) = 0 and c3(k) = 0 to the signal point 5903 on the basis of the signal point arrangement in Fig. 59. That is, in this case, the signal point 5903 corresponds to b'(k). <7> In a case where settings are made so that the signal point arrangement in Fig. 60 is used to generate b'(k), c2(k) = 0 and c3(k) = 0, and thus the mapper 5702 maps c2(k) = 0 and c3(k) = 0 to the signal point 6002 on the basis of the signal point arrangement in Fig. 60. That is, in this case, the signal point 6002 corresponds to b'(k). <8> In a case where settings are made so that the signal point arrangement in Fig. 61 is used to generate b'(k), c2(k) = 0 and c3(k) = 0, and thus the mapper 5702 maps c2(k) = 0 and c3(k) = 0 to the signal point 6104 on the basis of the signal point arrangement in Fig. 61. That is, in this case, the signal point 6104 corresponds to b'(k).

[0606] As described above, the relationship between "the bits and signal point arrangement for generating b(k)" and the relationship between "the bits and signal point arrangement for generating b'(k)" may be identical to or different from each other.

[0607] As an "example of a case where the relationships are identical", a description has been given of an example of using Fig. 58 to generate b(k) and using Fig. 58 to generate b'(k).

[0608] As an "example of a case where the relationships are different", a description has been given of an example of using Fig. 58 to generate b(k) and using Fig. 59 to generate b'(k), an example of using Fig. 58 to generate b(k) and using Fig. 60 to generate b'(k), and an example of using Fig. 58 to generate b(k) and using Fig. 61 to generate b'(k).

[0609] For another example, the modulation scheme for generating b(k) may be different from the modulation scheme for generating b'(k). Alternatively, the signal point arrangement on the in-phase I quadrature Q plane for generating b(k) may be different from the signal point arrangement on the in-phase I quadrature Q plane for generating b'(k).

[0610] For example, QPSK may be used as described above as the modulation scheme for generating b(k), and a modulation scheme of signal point arrangement different from QPSK may be used as the modulation scheme for generating b'(k). In addition, the signal point arrangement in Fig. 58 may be used as the signal point arrangement on the in-phase I quadrature Q plane for generating b(k), and a signal point arrangement different from that in Fig. 58 may be used as the signal point arrangement on the in-phase I quadrature Q plane for generating b'(k).

[0611] A state where the signal point arrangement on the in-phase I quadrature Q plane is different means, for example, when the coordinates of the four signal points on the in-phase I quadrature Q plane for generating b(k) is those in Fig. 58, at least one of the four signal points on the in-phase I quadrature Q plane for generating b'(k) does not overlap any of the four signal points in Fig. 58.

[0612] As described above, the mapped signal 5703A corresponds to the mapped signal 205_1 in Fig. 2, and the mapped signal 5703B corresponds to the mapped signal 205_2 in Fig. 2. Thus, the mapped signal 5703A and the mapped signal 5703B are to be subjected to phase change, CDD processing, and weight combining processing performed as in Figs. 3, 26, 38, 39, 40 to 48, 49 to 54, and so forth related to the signal processor 206 in Fig. 2 and so forth. However, in a case where ON / OFF of phase change is possible, phase change may be set to OFF, that is, phase change is not performed. In addition, in Figs. 3, 26, 38, 39, 40 to 48, and 49 to 54, a configuration not including a phase changer may be adopted.<Second Example>

[0613] Fig. 62 is a diagram illustrating an example of the configuration of the user #p signal processor 102_p different from the configurations in Figs. 2 and 56. In Fig. 62, the elements similar to those in Figs. 2 and 56 are denoted by the same numerals, and the description thereof is omitted. The user #p signal processor 102_p in Fig. 62 is different from that in Fig. 2 in that two error-correcting encoders 202_1 and 202_2 are included. In addition, the user #p signal processor 102_p in Fig. 62 is different from that in Fig. 56 in that one mapper 204 is included.

[0614] The mapper 204 in Fig. 62 receives the coded data 203_1 and 203_2 and the control signal 200. On the basis of information about a mapping method included in the control signal 200, the mapper 204 in Fig. 62 performs mapping, and outputs the mapped signals 205_1 and 205_2.

[0615] Fig. 63 is a diagram illustrating the second example of the operation of the mapper 5702. The operation of the mapper 5702 illustrated in Fig. 63 corresponds to an example of the operation of the mapper 204 illustrated in Fig. 62. In Fig. 63, the elements that operate similarly to those in Fig. 57 are denoted by the same numerals, and the description thereof is omitted. In addition, the control signal 5700 corresponds to the control signal 200 in Fig. 62, coded data 6301_1 corresponds to the coded data 203_1 in Fig. 62, coded data 6301_2 corresponds to the coded data 203_2 in Fig. 62, the mapped signal 5703A corresponds to the mapped signal 205_1 in Fig. 62, and the mapped signal 5701B corresponds to the mapped signal 205_2 in Fig. 62.

[0616] The mapper 5702 receives the coded data 6301_1 and 6301_2 and the control signal 5700. In a case where a robust transmission method is designated by the control signal 5700, the mapper 5702 performs the mapping described below, and outputs the mapped signals 5703A and 5703B.

[0617] For example, it is assumed that bit c0(k) and bit c1(k) are input as the coded data 6301_1 to the mapper 5702, and bit c2(k) and bit c3(k) are input as the coded data 6301_2 to the mapper 5702. Here, k is an integer equal to or greater than 0.

[0618] It is assumed that the mapper 5702 performs QPSK modulation on c0(k) and c1(k) to obtain a mapped signal a(k). In addition, it is assumed that the mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain a mapped signal b(k).

[0619] Also, it is assumed that the mapper 5702 performs QPSK modulation on c0(k) and c1(k) to obtain a mapped signal a'(k). In addition, it is assumed that the mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain a mapped signal b'(k).

[0620] The mapped signal 5703A with a symbol number i = 2k is represented by s1(i = 2k), and the mapped signal 5703B with a symbol number i = 2k is represented by s2(i = 2k). Also, the mapped signal 5703A with a symbol number i = 2k+1 is represented by s1(i = 2k+1), and the mapped signal 5703B with a symbol number i = 2k+1 is represented by s2(i = 2k+1).

[0621] In addition, s1(i = 2k), which is the mapped signal 5703A with a symbol number i = 2k, is represented by a(k), and s2(i = 2k), which is the mapped signal 5703B with a symbol number i = 2k, is represented by b(k). Also, s1(i = 2k+1), which is the mapped signal 5703A with a symbol number i = 2k+1, is represented by b'(k), and s2(i = 2k+1), which is the mapped signal 5703B with a symbol number i = 2k+1, is represented by a'(k).

[0622] An example of the relationship between a(k) and a'(k), and an example of the relationship between b(k) and b'(k) are similar to the relationships described by using Figs. 58, 59, 60, and 61.

[0623] As described above, the mapped signal 5703A corresponds to the mapped signal 205_1 in Fig. 62, and the mapped signal 5703B corresponds to the mapped signal 205_2 in Fig. 62. Thus, the mapped signal 5703A and the mapped signal 5703B are to be subjected to phase change, CDD processing, and weight combining processing performed as in Figs. 3, 26, 38, 39, 40 to 48, 49 to 54, and so forth related to the signal processor 206 in Fig. 62. However, in a case where ON / OFF of phase change is possible, phase change may be set to OFF, that is, phase change is not performed. In addition, in Figs. 3, 26, 38, 39, 40 to 48, and 49 to 54, a configuration not including a phase changer may be adopted.<Third Example>

[0624] The third example is, like the second example, an example of the operation of the mapper 204 in the configuration of the user #p signal processor 102_p illustrated in Fig. 62, that is, the configuration including the two error-correcting encoders 202_1 and 202_2 and the one mapper 204.

[0625] Fig. 64 is a diagram illustrating the third example of the operation of the mapper 5702. The operation of t...

Claims

1. A transmission apparatus, comprising: an error-correcting encoder (6502) configured to receive data (6501) and a control signal (300, 6500) and to perform error-correcting coding on the data (6501) based on information about an error-correcting code included in the control signal (300, 6500) to generate error-correcting coded data (6503); a mapper (6504) configured to receive the control signal (300, 6500) and the error-correcting coded data (6503) and to perform mapping based on information about a modulation scheme included in the control signal (300, 6500) to generate a first stream baseband signal (6505_1, 301A) and a second stream baseband signal (6505_2, 301B); a signal processor (6506) configured to receive the first stream baseband signal (6505_1) and the second stream baseband signal (6505_2), the control signal (300, 6500) and a signal group (110) and to output a first modulated signal (6506_A) and phase-changed second modulated signal (310B), the signal processor (6505) comprising a first phase changer (3801A), a second phase changer (3801B), a weight combiner (303), a third phase changer (305B), a first inserter (307A), a second inserter (307B) and a fourth phase changer (309B); wherein the weight combiner is (303) configured to receive the control signal (300, 6500) and perform weight combining on the first stream baseband signal (6505_1, 301A) and the second stream baseband signal (6505_2, 301B) to generate a first weighted signal signal (304A) and a second weighted signal (304B), wherein a phase change after weight combining is applied by the third phase changer (305B) to the second weighted signal (304B); the first inserter (307A) is configured to input the first weighted signal (304A), a first pilot symbol signal (351A), a preamble signal (352) a control information symbol signal (353) and the control signal (300, 6500) and to output, based on information about a frame configuration included in the control signal (300, 6500), the first modulated signal (6506_A); the second inserter (307B) is configured to input the second weighted signal (306B) to which the phase change after weight combining has been applied, a second pilot symbol signal (351B), the preamble signal (352), the control information symbol signal (353) and the control signal (300, 6500) and to output, based on the information about the frame configuration included in the control signal (300, 6500), the second modulated signal (6506_B); the fourth phase changer (309B) is configured to input the control signal (300, 6500) and to apply phase change to the second modulated signal (6506_B) at the output of the second inserter (307B) to output a phase-changed second modulated signal (310B); the transmission apparatus further comprising: a first radio section and a second radio section (6507_A, 6507_B) configured to receive the control signal (300, 6500) and perform signal processing on the first modulated signal (6506_A) and the phase-changed second modulated signal (310B), respectively, and to output a first transmission signal (6508_A) and a second transmission signal (6508_B), respectively; and a first antenna section (6509_A) and a second antenna section (6509_B) configured to output the first transmission signal (6508_A) and the second transmission signal (6508_B), respectively, as radio waves; wherein the first phase changer (3801A) and / or the second phase changer (3801B) are configured to receive the control signal (300, 6500) and apply, on the basis of information about a phase change method included in the control signal (300, 6500), at least one of a first phase change before weight combining on the first stream baseband signal (6505_1, 301A) and a second phase change before weight combining on the second stream baseband signal (6505_2, 301B), respectively, an amount Vp(i) of the first phase change before weight combining and an amount vp(i) of the second phase change before weight combining being switched symbol by symbol and given by Vp i = e j k × π × i N + Δ and νp i = e j − k × π × i N + Ω where j is the imaginary unit, k is a non-zero integer, i is a symbol number, N is a period of phase change, N being equal to or greater than 3, and Δ and Ω are real numbers, wherein a switching between performing and not performing the first phase change before weight combining, the second phase change before weight combining and the phase change after weight combining is performed based on the control signal, wherein the first transmission signal (6508_A) and the second transmission signal (6508_B) are signals at identical times and identical frequencies, and wherein π / 2 shift Binary Phase Shift Keying, BPSK, is used at the mapper (6504).

2. The transmission apparatus according to claim 1, wherein the first radio section and the second radio section (6507_A, 6507_B) uses either a first orthogonal frequency-division multiplexing, OFDM, transmission mode or a single-carrier scheme.

3. The transmission apparatus according to claim 1, wherein no phase change after weight combining is applied to the first weighted signal (304A) before it is input to the first inserter (307A).

4. A transmission method, comprising: performing error-correcting coding on received data (6501), based on information about an error-correcting code included in a received control signal (300, 6500) to generate error-correcting coded data (6503); performing mapping of the error-correcting coded data (6503) based on information about a modulation scheme included in the received control signal (300, 6500) to generate a first stream baseband signal (6505_1, 301A) and a second stream baseband signal (6505_2, 301B); performing signal processing on the first stream baseband signal (6505_1, 301A) and the second stream baseband signal (6501A, 301B) to output a first modulated signal (6506_A) and a phase-changed second modulated signal (310B), wherein the signal processing on the first stream baseband signal (6505_1, 301A) and the second stream baseband signal (6501A, 301B) includes: receiving the control signal (300, 6500); receiving a signal group (110); applying at least one of a first phase change before weight combining on the first stream baseband signal (6505_1, 301A) and a second phase change before weight combining on the second stream baseband signal (6505_2, 301B) respectively, on the basis of information about a phase change method included in the control signal (300, 6500); performing weight combining on the first stream baseband signal (6505_1, 301A) and the second stream baseband signal (6501A, 301B) to which at least one of the first or second phase change has been applied, respectively to generate a first weighted signal (304A) and a second weighted signal (304B), wherein a phase change after weight combining is applied to the second weighted signal (304B) after weight combining; inserting to the first weighted signal (304A), a first pilot symbol signal (351A), a preamble signal (352) and a control information symbol signal (353) and outputting, based on information about a frame configuration included in the control signal (300), the first modulated signal (6506_A); inserting to the second weighted signal (306B) to which the phase change after weight combining has been applied, a second pilot symbol signal (351B), the preamble signal (352) and the control information symbol signal (353) and outputting, based on the information about the frame configuration included in the control signal (300, 6500), the second modulated signal (6506_B); applying a phase change to the second modulated signal (6506_B) based on the control signal (300, 6500) to output the phase-changed second modulated signal (310B); wherein the method further comprises: performing signal processing on the first modulated signal (6506_A) and the phase-changed second modulated signal (310B) and outputting a first transmission signal (6508_A) and a second transmission signal (6508_B), respectively, based on the received control signal (300, 6500); and outputting the first transmission signal (6508_A) and the second transmission signal (6508_B) via a first antenna section (6509_A) and a second antenna section (6509_B), respectively, as radio waves, based on the received control signal (300, 6500); wherein an amount vp(i) of the second phase change before weight combining being switched symbol by symbol and given by Vp i = e j k × π × i N + Δ and νp i = e j − k × π × i N + Ω where j is the imaginary unit, k is a non-zero integer, i is a symbol number, N is a period of phase change, N being equal to or greater than 3, and Δ and Ω are real numbers, wherein a switching between performing and not performing the first phase change before weight combining , the second phase change before weight combining and the phase change after weight combining is performed based on a control signal, wherein the first transmission signal (6508_A) and the second transmission signal (6508_B) are signals at identical times and identical frequencies, and wherein π / 2 shift Binary Phase Shift Keying, BPSK, is used at the mapping.

5. The transmission method according to claim 4, wherein the transmitting of the first transmission signal (6508_A) and of the second transmission signal (6508_B) uses either a first orthogonal frequency-division multiplexing, OFDM, transmission mode or a single-carrier scheme.

6. The transmission method according to claim 4, wherein no phase change after weight combining is applied to the first weighted signal (304A) before insertion of the first pilot symbol signal (351A), the preamble signal (352) and the control information symbol signal (353).