JP5388682B2 - Transmitter, receiver and communication device - Google Patents

Description

  The present invention relates to a transmitter, a receiver, and a communication apparatus that perform multicarrier communication to which frequency diversity is applied.

  In recent years, the demand for high-speed data transmission has been increasing. OFDM (Orthogonal Frequency Division Multiplexing) is a multi-carrier system that transmits and receives data on multiple subcarriers (frequency), and is good even if there is a delayed wave (a signal that is received after being reflected by a building, etc.) Therefore, it is often used in high-speed wireless communication systems and power line communication.

  Also, a method called single carrier OFDM (hereinafter referred to as SC-OFDM), which improves the drawback of OFDM that the amplitude of the time waveform becomes large, has been studied. Similarly to OFDM, SC-OFDM can be regarded as transmitting data in parallel at a plurality of frequencies, that is, in principle, it can be regarded as a multi-carrier system. There is a feature that quality is obtained.

  Here, the communication quality is affected by fading, interference, and noise on the transmission path, and there is a method called frequency diversity as a method of reducing these effects. Frequency diversity transmits and receives the same data at multiple frequencies. As a result, even if the signal is attenuated by fading at a specific frequency or when large interference or noise is mixed, the same data is transmitted at another frequency, so that data errors are unlikely to occur. There is a feature (see, for example, Patent Document 1 below). Frequency diversity can be applied to both OFDM and SC-OFDM systems.

International Publication No. 07/032491

  In order to realize frequency diversity, since it is necessary to transmit the same data at different frequencies, the same signals are arranged in the frequency direction. Then, a large peak occurs in the amplitude of the transmission signal.

  In order to transmit and receive a waveform having a peak amplitude, it is necessary to increase the dynamic range of the analog circuit or digital circuit in the communication device so that the peak amplitude is not clipped. The communication device becomes complicated, the device scale increases, and the price of the device and the communication system also increases. Also, if the transmission power is reduced so that the peak amplitude is not clipped, it is greatly affected by fading, interference, and noise, and good communication quality cannot be maintained. That is, when the peak amplitude occurs, there is a problem that the communication apparatus becomes large or is easily affected by fading, interference, and noise.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a transmitter, a receiver, and a communication device that transmit and receive a multicarrier signal while suppressing the occurrence of peak amplitude when performing frequency diversity.

  In order to solve the above-mentioned problems and achieve the object, the present invention provides a transmitter for transmitting a multicarrier signal, a frequency copy means for copying the same data in the frequency domain, and an output from the frequency copy means Frequency scrambling means for randomizing the signal, and frequency time conversion means for converting the output signal from the frequency scrambling means into a signal in the time domain.

  According to the present invention, since the transmitter copies the transmission signal in the frequency domain and further performs randomization processing, the transmitter transmits the peak amplitude in multicarrier communication to which frequency diversity is applied. Can be suppressed and communication quality can be improved.

FIG. 1 is a diagram illustrating a configuration example of a transmitter according to a first embodiment of a transmitter included in a communication device according to the present invention. FIG. 2 is a diagram illustrating a configuration example of the first embodiment of the receiver included in the communication device according to the present invention. FIG. 3 is a diagram for explaining the operation of the transmitter according to the first embodiment. FIG. 4 is a diagram illustrating the relationship between the signal before the randomization process and the signal after the randomization process. FIG. 5 is a diagram illustrating a configuration example of the PN sequence generation unit. FIG. 6 is a diagram illustrating another configuration example of the transmitter according to the first embodiment. FIG. 7 is a diagram for explaining the effectiveness of the transmitter according to the first embodiment. FIG. 8 is a diagram for explaining the operation of the receiver according to the first embodiment. FIG. 9 is a diagram for explaining the effect of the communication apparatus according to the first embodiment. FIG. 10 is a diagram illustrating a configuration example of a transmitter included in the communication apparatus according to the second embodiment. FIG. 11 is a diagram illustrating a configuration example of a receiver included in the communication apparatus according to the second embodiment. FIG. 12 is a diagram illustrating a configuration example of the frequency synthesizer when the number of subcarriers is eight. FIG. 13 is a diagram for explaining the operation of the transmitter when the number of branches information = 4. FIG. 14 is a diagram for explaining the operation of the receiver when the branch number information = 4. FIG. 15 is a diagram illustrating a configuration example of a frequency scrambler included in the transmitter according to the third embodiment. FIG. 16 is a diagram illustrating a configuration example of a frequency scrambler included in the transmitter according to the third embodiment. FIG. 17 is a diagram illustrating a configuration example of a frequency descrambler included in the receiver according to the third embodiment. FIG. 18 is a diagram illustrating a configuration example of a frequency scrambler included in the transmitter according to the fourth embodiment. FIG. 19 is a diagram illustrating a configuration example of a frequency scrambler included in the transmitter according to the fourth embodiment. FIG. 20 is a diagram illustrating a configuration example of a frequency descrambler included in the receiver according to the fourth embodiment. FIG. 21 is a diagram illustrating a configuration example of a frequency descrambler included in the receiver according to the fourth embodiment. FIG. 22 is a diagram illustrating a configuration example of a frequency scrambler included in the transmitter according to the fifth embodiment. FIG. 23 is a diagram illustrating a configuration example of a frequency descrambler included in the receiver according to the fifth embodiment. FIG. 24 is a diagram for explaining the operation of the phase converter when the amount of phase rotation is four. FIG. 25 is a diagram illustrating a configuration example of a frequency synthesizer included in the receiver according to the sixth embodiment. FIG. 26 is a diagram illustrating a configuration example of a frequency synthesis unit included in the receiver according to the seventh embodiment. FIG. 27 is a diagram illustrating a configuration example of a frequency scrambler included in the transmitter according to the eighth embodiment. FIG. 28 is a diagram for explaining the operation of the communication apparatus according to the eighth embodiment. FIG. 29 is a diagram illustrating a configuration example of a transmitter according to the ninth embodiment. FIG. 30 is a diagram illustrating a configuration example of a receiver according to the ninth embodiment. FIG. 31 is a diagram illustrating a configuration example of the frequency copy unit. FIG. 32 is a diagram showing an example of a communication system configured by the communication apparatus according to the present invention. FIG. 33 is a diagram illustrating a configuration example of a communication system according to the eleventh embodiment. FIG. 34 is a diagram illustrating a configuration example of a communication system according to the twelfth embodiment. FIG. 35 is a diagram illustrating an example of a frame format of a communication system in which branch number information is transmitted through a broadcast channel. FIG. 36 is a diagram showing an example of a frame format in which the PN sequence is changed for each user. FIG. 37 is a diagram showing an example of a frame format in which the PN sequence is changed for each base station. FIG. 38 is a diagram for explaining the communication system according to the seventeenth embodiment. FIG. 39 is a diagram for explaining the communication system according to the eighteenth embodiment.

  Hereinafter, embodiments of a transmitter, a receiver, and a communication device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1 is a diagram illustrating a configuration example of a transmitter according to a first embodiment of a transmitter included in a communication device according to the present invention. FIG. 2 is a diagram illustrating a configuration example of the first embodiment of the receiver included in the communication device according to the present invention. These FIG. 1 and FIG. 2 show configuration examples when the multicarrier signal transmitted and received by the communication apparatus is an orthogonal frequency division multiplexing (OFDM) signal.

  The transmitter 1 shown in FIG. 1 converts transmission data that is a digital signal into a transmission signal that is an analog signal. For example, if the transmitter 1 constitutes a communication device that performs wireless communication, the transmitter 1 may constitute a communication device that transmits a transmission signal to an antenna (not shown) and performs power line communication. If so, the transmission signal is sent to a power line (not shown).

  On the other hand, when the receiver 2 shown in FIG. 2 receives an analog signal similar to the signal transmitted by the transmitter 1, the receiver 2 extracts the transmitted data from the received signal and outputs it as received data. For example, if the receiver 2 configures a communication device that performs wireless communication, the receiver 2 acquires a received signal from an antenna (not shown) and configures a communication device that performs power line communication. A received signal is acquired from a power line (not shown).

  Hereinafter, an internal configuration and detailed operation of the transmitter 1 and the receiver 2 of the present embodiment will be described.

  The transmitter 1 of this embodiment (see FIG. 1) includes a mapping unit 101, a frequency copy unit 102, a serial / parallel conversion unit (hereinafter referred to as an S / P unit) 105, a frequency scrambler 106, and a reset signal generation unit. 109, an IFFT unit 110 and an analog TX unit 111. The frequency copy unit 102 includes a memory 103 and a selector 104, and the frequency scrambler 106 includes a plurality of multipliers 107 and a PN sequence generation unit 108.

  The mapping unit 101 converts the input transmission data into a complex signal according to a modulation scheme such as QPSK or 16QAM. For example, in the case of QPSK, 2 bits of transmission data are converted into one of four signal points 1 + j, -1 + j, -1-j, and 1-j.

  The frequency copy unit 102 realizes a function of copying the output signal of the mapping unit 101. Here, the memory 103 is a FIFO (First In First Out) type memory that outputs memory input signals in the order of input after a predetermined time. The output signal of the mapping unit 101 is input to both the memory 103 and the selector 104. The selector 104 first selects a signal directly input from the mapping unit 101 and outputs it to the S / P unit 105 in the subsequent stage. The signal output from the memory 103 is selected and output to the subsequent S / P unit 105. That is, the same signal is input to the S / P unit 105 twice in succession.

  The S / P unit 105 parallelizes and outputs a serial signal that is a signal input from the frequency copy unit 102.

  The frequency scrambler 106 receives the output signal from the S / P unit 105 and randomizes it. Specifically, the PN sequence generation unit 108 generates a PN (Pseudo Noise) sequence, that is, a pseudo-random sequence of “0” and “1”, and the multiplier 107 generates an S / P unit 105 based on the PN sequence. The sign of the signal received from is reversed. For example, when the output signal of the S / P unit 105 is 16QAM and the signal is represented by 1 + 3j, if the output of the PN sequence generation unit 108 is “0”, the multiplier 107 outputs 1 + 3j as it is, If the output of the PN sequence generator 108 is “1”, the multiplier 107 outputs −1−3j obtained by inverting the sign of 1 + 3j.

  Reset signal generation section 109 generates a signal for resetting PN sequence generation section 108 for each OFDM symbol. That is, a reset signal is output for each OFDM symbol to the PN sequence generation unit 108 (instructed to reset).

  The IFFT unit 110 performs IFFT (Inverse Fast Fourier Transform) on the parallel signal output from the frequency scrambler 106, and converts the signal on the frequency axis to the signal on the time axis.

  The analog TX unit 111 converts the digital signal input from the IFFT unit 110 into a desired analog signal and generates a transmission signal. The analog TX unit 111 includes analog devices such as a D / A (digital / analog converter), a filter, and an amplifier.

  The receiver 2 (see FIG. 2) of the present embodiment includes an analog RX unit 201, an FFT unit 202, a synchronous detection unit 203, a frequency descrambler 206, a reset signal generation unit 209, a frequency synthesis unit 210, and parallel / serial. A conversion unit (hereinafter referred to as a P / S unit) 212 and a demapping unit 213 are provided. The synchronous detection unit 203 includes a plurality of multipliers 204 and a transmission path estimation unit 205, the frequency descrambler 206 includes a plurality of multipliers 207 and a PN sequence generation unit 208, and the frequency synthesis unit 210 includes: A plurality of adders 211 are included.

  The analog RX unit 201 converts an input received signal into a digital signal. The received signal is input from an antenna (not shown) for wireless communication, and input from a power line (not shown) for power line communication.

  The FFT unit 202 performs FFT (Fast Fourier Transform) on the signal output from the analog RX unit 201 and converts the signal into a signal on the frequency axis.

  The synchronous detection unit 203 performs synchronous detection on the signal output from the FFT unit 202. Specifically, the multiplier 204 multiplies the output signal of the FFT unit 202 by the transmission path estimation result by the transmission path estimation unit 205 to obtain a synchronous detection result. Here, the estimation of the transmission path is performed, for example, by transmitting a known signal such as a preamble on the transmission side and receiving it on the reception side. By multiplying the reception signal (output signal of the FFT unit 202) by the transmission path estimation result, the amplitude and phase shift received by the transmission signal on the transmission path are corrected.

  The frequency descrambler 206 cancels randomization (corresponding to the randomization performed by the frequency scrambler 106 of the transmitter 1 described above) performed when the transmission-side communication device generates a transmission signal. Specifically, PN sequence generation section 208 generates a PN sequence, and multiplier 207 inverts the sign of the signal received from FFT section 202 based on the PN sequence. The PN sequence generation unit 208 is the same as the PN sequence generation unit 108 constituting the transmitter 1. That is, the code inversion process executed here is the same as the code inversion process in the transmitter 1, and the description thereof is omitted. Thereby, the sign inversion (randomization) performed in the transmitter 1 is canceled, and the signal before the sign inversion is restored.

  Reset signal generation section 209 generates a signal for resetting PN sequence generation section 208 for each OFDM symbol. The reset signal generation unit 209 is the same as the reset signal generation unit 109 constituting the transmitter 1.

  The frequency synthesizer 210 synthesizes signals on the frequency axis to which the same data is transmitted among a plurality of signals output from the frequency descrambler 206. Specifically, the signals transmitted with the same data are added by the adder 211 to generate a combined signal.

  A parallel / serial conversion unit (hereinafter referred to as a P / S unit) 212 serializes and outputs a parallel signal that is a signal input from the frequency synthesis unit 210.

  The demapping unit 213 performs the reverse operation of the mapping unit 101 that constitutes the transmitter 1. That is, the transmitted data is restored by demapping the input signal in accordance with the applied modulation scheme (QPSK, 16QAM, etc.), and the restored data is output as received data.

  Next, details of the operation of the transmitter 1 will be described with reference to the drawings.

  FIG. 3 is a diagram for explaining the operation from the frequency copy unit 102 to the frequency scrambler 106 of the transmitter 1. As shown in the figure, here, the signal output from the mapping unit 101 (corresponding to the mapped signal shown in the figure) is 8 symbols s0 to s7, and this is the unit handled by the transmitter 1 in one transmission process. An operation example in the case (when one OFDM symbol is generated based on s0 to s7) will be described. For example, when BPSK is applied as a modulation method, each symbol (s0 to s7) takes two values of +1 and −1, and when QPSK is applied, + 1 + j and −1 + j. , -1-j, + 1-j.

  When the frequency copy unit 102 receives the signal (mapped signal) output from the mapping unit 101, first, the selector 104 outputs the received s0 to s7 as it is, and the memory 103 outputs these s0 to s7. save. Thereafter, when a predetermined time elapses, the selector 104 selects an output from the memory 103 and outputs s0 to s7 held in the memory 103. As a result, the output of the frequency copy unit 102 is “s0, s1, s2, s3, s4, s5, s6, s7, s0, s1, s2, s3, s4, s5, s6, s7”. The series repeated twice is input to the S / P unit 105 as a signal after frequency copying.

  The S / P unit 105 parallelizes each symbol input from the frequency copy unit 102 and inputs the symbol to the frequency scrambler 106.

  The frequency scrambler 106 randomizes the input signal from the S / P unit 105 based on the PN system. Specifically, each symbol received from the S / P unit 105 is input to the corresponding multiplier 107, and each multiplier 107 outputs the received symbol (input symbol) from the PN sequence generation unit 108. The sign inversion processing is executed according to the state of a specific bit (bit associated with itself) in the generated PN sequence, and the obtained processing result is output as a randomization execution result. As described above, each multiplier 107 outputs a symbol obtained by inverting the sign of the input symbol when the bit (corresponding bit) associated with itself is “1”, and the corresponding bit is “ In the case of 0 ″, the same symbol as the input symbol is output. In the example shown in FIG. 3, since the PN sequence is “0,1,0,1,1,0,0,1,0,0,0,1,1,1,1,0”, it is randomized. The signal after execution (frequency scrambler output) is shown in the figure as “s0, -s1, s2, -s3, -s4, s5, s6, -s7, s0, s1, s2, -s3, -s4, -s5, -s6, s7 ”. The signal output from the frequency scrambler 106 is converted into a signal on the time axis by the IFFT unit 110. That is, the signal up to the IFFT unit 110 is a signal on the frequency axis.

  In addition, the case where the sign of the symbol having the corresponding bit of “1” in the PN sequence is reversed has been described. On the contrary, the sign of the symbol having the corresponding bit of “0” is reversed, and the corresponding bit is set to “1”. The symbol "" may be configured not to reverse the sign. As can be seen from the description, the multiplier 107 does not simply multiply the input signal (symbol) from the S / P unit 105 by the corresponding bit in the PN sequence, but in accordance with the state of the corresponding bit. Is output as it is or after the sign is inverted.

  FIG. 4 is a diagram showing the relationship between the signal before the randomization process and the signal after the execution. The upper stage shows the spectrum of the input signal (signal before the randomization execution) to the frequency scrambler 106, and the lower stage. Indicates the spectrum of the output signal from the frequency scrambler 106 (signal after execution of randomization). As shown in the figure, the same signals (symbol strings s0 to s7) are repeatedly arranged on the frequency axis before the randomization is executed, whereas the same signals are not repeated on the frequency axis after the randomization is executed. Therefore, in the transmitter 1, the effect that the peak amplitude is not generated in the time waveform (the peak of the amplitude can be reduced) is obtained. Furthermore, in the signal after randomization output from the frequency scrambler 106, the same data is transmitted at the frequency farthest on the frequency axis (the distance between symbols carrying the same data is the same). Therefore, the effect of maximizing the effect of frequency diversity can be obtained.

  Incidentally, as another method for preventing the same signal from being arranged on the frequency axis, for example, a configuration in which symbols are arranged at different frequencies by interleaving without performing inversion of the sign of the signal (symbol) can be considered. In such a configuration (a configuration in which only the arrangement of symbols is replaced), the same data may be arranged at a close frequency, and thus the frequency diversity effect cannot be maximized as in the present invention.

  Reset signal generation section 109 resets PN sequence generation section 108 for each OFDM symbol. In the example of FIG. 3, one OFDM symbol is composed of 16 complex signals of s0, s1, s2, s3, s4, s5, s6, s7, s0, s1, s2, s3, s4, s5, s6, s7. Therefore, the reset signal generator 109 outputs a signal (reset signal) for resetting the PN sequence generator 108 for every 16 complex signals. As a result, each OFDM symbol transmitted from the transmitter 1 is always generated based on a complex signal sequence (output of the frequency scrambler 106) randomized using a PN sequence having the same pattern.

FIG. 5 is a diagram illustrating a configuration example of the PN sequence generation units 108 and 208. As illustrated, the PN sequence generators 108 and 208 include a plurality (seven in this example) of pairs of delay circuits 301 and selectors 302, a plurality (three in this example) of exclusive ORs 303, And an initial value memory 304. In this example, since there are seven delay circuits 301, a 127-bit (= 2 ⁷ −1) long PN sequence is generated. In the PN sequence generators 108 and 208, the delay circuit 301 stores the bit one clock earlier. The selector 302 normally selects the output of the delay circuit 301. When the reset signal is input, the selector 302 selects the initial value memory 304 and inputs it to the delay circuit 301 at the subsequent stage, and the value held by the delay circuit 301 is initialized. Turn into. When no reset signal is input, the PN sequence generation unit 108 continues to repeatedly generate a 127-bit PN sequence. When a reset signal is input, an initial value is loaded and initialized in the middle of a 127-bit PN sequence.

  As described above, in the present embodiment, reset signal generation section 109 outputs a reset signal for each OFDM symbol, so in the example shown in FIG. 3, the output of PN sequence generation section 108 is “0, 1,0,1,1,0,0,1,0,0,0,1,1,1,1,0 "is repeated for each OFDM symbol. As a result, the receiver 2 that receives the signal transmitted by the transmitter 1 does not need to synchronize the PN sequence generator 208, and the receiver circuit can be simplified (details will be described later).

  The signal converted into the signal on the time axis by the IFFT unit 110 is converted into a desired analog signal by the analog TX unit 111 and sent to the transmission path. The analog TX unit 111 includes a D / A (digital / analog) converter, an amplifier, a filter, and the like, and executes various signal processes on the input signal. Then, if the obtained signal is transmitted via a wireless transmission path, it is converted into an analog signal to be supplied to the antenna and output, and if it is transmitted via a wired transmission path such as a power line, the wired transmission path Is converted into an analog signal to be supplied and output. Since both are general, detailed description is omitted.

  Instead of the configuration shown in FIG. 1, a configuration as shown in FIG. 6 can be adopted. FIG. 6 is a diagram illustrating another configuration example of the transmitter according to the present embodiment. The illustrated transmitter 1a deletes the frequency scrambler 106 from the transmitter 1 described above, and further converts the frequency scrambler 106a to a frequency. A configuration added between the copy unit 102 and the S / P unit 105 is adopted. The frequency scrambler 106 a includes a single multiplier 107 and a PN sequence generator 108. Similar to the frequency scrambler 106, in the frequency scrambler 106a, the multiplier 107 performs a code inversion process, which is a randomization process of an input signal (symbol), based on the output (PN sequence) of the PN sequence generation unit 108. When the configuration of FIG. 6 is employed, the number of multipliers 107 constituting the frequency scrambler can be reduced as compared with the case of employing the configuration of FIG.

  FIG. 7 is a diagram for explaining the effectiveness of the transmitters 1 and 1a of the present embodiment, and an example of an output signal (time waveform) of the IFFT unit 110 is acquired by simulation. In FIG. 7, (a) is a direct IFFT of the output of the frequency copy unit 102 (an IFFT without executing the randomization process (sign inversion process) in the frequency scrambler 106 or 106a). It corresponds to the time waveform. On the other hand, (b) shows a time waveform generated by the transmitter of the present embodiment by IFFT of the output of the frequency scrambler 106 or 106a (signal obtained by executing the randomization process). FIG. 7 shows that the transmitter according to the present embodiment has an effect that the peak amplitude is not generated in the time waveform (the peak value of the amplitude can be suppressed low).

  Next, details of the operation of the receiver 2 will be described with reference to the drawings.

  FIG. 8 is a diagram for explaining operations from the FFT unit 202 to the frequency synthesis unit 210 of the receiver 2 (see FIG. 2). Here, as an example, the operation when the transmitter 1 performs the above-described operation (the operation shown in FIG. 3) and receives the transmitted signal, that is, the communication device that is the communication partner transmits the above-described transmission. An operation in the case of receiving a signal having the same configuration as that of the machine 1 or 1a and executing the operation shown in FIG. 3 will be described. In order to simplify the explanation, the synchronous detection unit 203 of the receiver 2 ideally performs transmission path estimation to completely correct the amplitude and phase shift in the transmission path, and noise is This will be described assuming that there is no situation. However, these conditions only simplify the description and do not limit the implementation environment of the present invention.

  As shown in the figure, in the receiver 2, the synchronous detection unit 203 performs synchronous detection on the received signal, and the obtained signal (corresponding to the signal after synchronous detection shown in the figure) is transmitted to the transmitter 1 (which is provided in the opposing communication device). The same signal as the output of the frequency scrambler 106, ie, “s0, -s1, s2, -s3, -s4, s5, s6, -s7, s0, s1, s2, -s3, -s4, -s5, -s6, s7 ”. The PN sequence generation unit 208 generates the same sequence as the PN sequence generation unit 108 of the transmitter 1, and as a result, the output of the frequency descrambler 206 is the same signal as the input of the frequency scrambler 106 of the transmitter 1, that is, “s0, s1, s2, s3, s4, s5, s6, s7, s0, s1, s2, s3, s4, s5, s6, s7 ”. In the frequency synthesizer 210, the adder 211 adds signals having the same frequency to which the same data is transmitted. As a result, the output signal from each adder 211 is s0 + s0 = 2s0, s1 + s1 = 2s1, ..., s7 + s7 = 2s7. As described above, since a plurality of (two in this example) signals are added by the frequency synthesizer 210, even if one transmission signal deteriorates due to fading, interference, or noise in the transmission path, If the quality is good, it is possible to prevent the communication quality from being extremely deteriorated.

  FIG. 9 is a diagram for explaining the effect of the communication apparatus according to the present embodiment, taking as an example a case where a transmission signal in a part of the frequency band (in this example, a high frequency part) is attenuated on the transmission line. . As shown in FIG. 9, in communication by the communication apparatus of the present embodiment, the transmission side repeatedly transmits a signal (s0 to s7) mapped with transmission data on the frequency axis, transmits it, and receives it. Since the frequency is synthesized on the side, even if a part of the frequency band is attenuated and deteriorated, the signal after frequency synthesis is not greatly attenuated, and good communication quality can be maintained.

  Here, the receiver 2 resets so that the PN sequence output from the PN sequence generation unit 208 is initialized for each OFDM symbol (so that the PN sequence having the same pattern is repeatedly output for each OFDM symbol). A signal generator 209 generates a reset signal. This is because the receiver 2 does not require a PN series synchronization circuit and the circuit scale of the receiver 2 is reduced. That is, the PN sequence generation unit 208 of the receiver 2 needs to generate a PN sequence at the same timing as the PN sequence generation unit 108 of the opposing communication device (transmitter 1). If reset is performed for each OFDM symbol, the generation timing of the PN sequence is aligned. As described above, in the transmitter 1, the frequency scrambler 106 randomizes the transmission signal using the PN sequence that is initialized for each OFDM symbol. Control is performed so that the PN sequence output from is initialized for each OFDM symbol. Here, since the OFDM symbol period may be obtained from an OFDM symbol synchronization circuit (not shown) in the receiver, the PN sequence generator 208 is connected to the PN sequence generator 108 of the transmitter 1 in the receiver 2. A new synchronization circuit for generating a PN sequence in synchronization is unnecessary, and the circuit scale of the receiver 2 can be reduced.

  As described above, in the communication apparatus according to the present embodiment, the transmitter converts the transmission data according to the applied modulation scheme, copies the obtained complex signal in the frequency domain, and further transmits each complex signal. The code is transmitted after being subjected to randomization processing (code inversion processing) based on the PN sequence. In addition, the receiver first performed the reverse process of the randomization process performed on the transmission side (transmitter) to cancel the randomization, and further obtained by synthesizing a plurality of the same complex signals. The transmission data was restored from the combined complex signal. Thereby, it is possible to suppress the occurrence of peak amplitude in communication to which frequency diversity is applied, and it is possible to improve communication quality.

Embodiment 2. FIG.
FIG. 10 is a diagram illustrating a configuration example of a transmitter included in the communication apparatus according to the second embodiment. The transmitter 1b according to the present embodiment is obtained by replacing the frequency copy unit 102 of the transmitter 1a (see FIG. 6) described in the first embodiment with a frequency copy unit 102b. In the present embodiment, the description of the components common to the transmitter 1a already described in the first embodiment (components denoted by the same reference numerals) is omitted.

  In the transmitter 1a, the number of copies by the frequency copy unit 102 is fixed (one time), whereas in the transmitter 1b of the present embodiment, the number of copies by the frequency copy unit 102b is variable. In the present embodiment, an example in which the frequency copy unit 102 of the transmitter 1a having a smaller device configuration is replaced with the frequency copy unit 102b will be described. However, the frequency copy unit 102 of the transmitter 1 (see FIG. 1). Can be replaced with the frequency copy unit 102b. In this case, the same effect can be obtained.

  As shown in FIG. 10, the frequency copy unit 102b is obtained by adding a selection control unit 112 to the frequency copy unit 102 (see FIGS. 1 and 6) described in the first embodiment. Hereinafter, the number of multiplexed identical data is referred to as the number of branches. For example, if “the number of branches = 2”, the same data is frequency copied once and the same data is arranged twice on the frequency axis.

  The selection control unit 112 controls the read address of the memory 103 and the selector 104 according to the set branch number information. Thereby, the frequency copy unit 102b copies the output of the mapping unit 101 a plurality of times in accordance with the branch number information. In other words, the selection control unit 112 first controls the selector 104 to select the output of the mapping unit 101, and then controls to select the memory 103, and further, the memory is performed by one less than the branch number information. Control to select 103. At this time, the read address of the memory 103 is repeatedly specified by one less than the branch number information. As a result, the signal output from the mapping unit 101 is output as it is from the frequency copy unit 102b to the frequency scrambler 106a, and then the signal read from the memory 103 is output “number of branches−1” times. The That is, the frequency copy unit 102b repeatedly outputs the same signal to the frequency scrambler 106a as many times as the number of branches.

  FIG. 11 is a diagram illustrating a configuration example of a receiver included in the communication apparatus according to the second embodiment. The receiver 2b of the present embodiment is obtained by replacing the frequency synthesizer 210 of the receiver 2 (see FIG. 2) described in the first embodiment with a frequency synthesizer 210b. In the present embodiment, the description of the components common to the receiver 2 described in the first embodiment (components denoted by the same reference numerals) is omitted.

  In the receiver 2b, the frequency synthesizer 210b adds signals on the frequency axis to which the same data is transmitted according to the branch number information.

  FIG. 12 is a diagram illustrating a configuration example of the frequency synthesizer 210b when the number of subcarriers (number of frequencies) is eight. In this case, the frequency synthesizer 210b includes a plurality of adders (corresponding to the illustrated adders 211-1, 211-2, and 211-3) and a selection unit 214.

  As shown in FIG. 12, for example, when the inputs to the frequency synthesizer 210b are represented as a0 to a7, these inputs are branched into two systems, and one of the branches is input to the selector 214, One is input to the first stage adder 211-1. In the first stage adder 211-1, a0 + a4, a1 + a5, a2 + a6, a3 + a7 are calculated. These addition results are also branched into two systems, one is input to the selection unit 214, the other is input to the second stage adder 211-2, and is further added by the adder 211-2. Note that the addition result in the adder 211-2 is a0 + a2 + a4 + a6, a1 + a3 + a5 + a7. These addition results are also branched into two systems, similar to the above addition results, one being input to the selection unit 214 and the other being input to the third-stage adder 211-3. The adder 211-3 executes addition processing and outputs the addition result a0 + a1 + a2 + a3 + a4 + a5 + a6 + a7 to the selection unit 214. The selection unit 214 selects and outputs one of these addition results according to the branch number information. For example, when the number of branches information = 1 (when frequency copying is not performed), a0 to a7 that are inputs to the frequency synthesizer 210b are selected and output (the signal input from the frequency descrambler 206 is output as it is. ). When the branch number information = 2, a0 + a4, a1 + a5, a2 + a6, a3 + a7 (output signals from the first stage adder 211-1) are selected and output, and the branch number information = In the case of 4, a0 + a2 + a4 + a6, a1 + a3 + a5 + a7 (output signal from the second stage adder 211-2) are selected and output, and when the number of branches information = 8 , A0 + a1 + a2 + a3 + a4 + a5 + a6 + a7 (output signal from the third stage adder 211-3) is selected and output.

  Hereinafter, the overall operation of the transmitter 1b and the receiver 2b will be described with reference to the drawings. In addition, description is abbreviate | omitted about operation | movement common with the transmitters 1 and 1a demonstrated in Embodiment 1, and the receiver 2. FIG.

  FIG. 13 is a diagram for explaining the operation of the transmitter 1b when the number-of-branch information = 4. Specifically, it is a diagram for explaining the operation from the frequency copy unit 102b to the frequency scrambler 106a. is there. When the number of branches information = 4, as shown in the figure, the frequency copy unit 102b repeatedly copies the mapped signals s0 to s3 three times and outputs the same signal four times in total (signal after frequency copying). Since the output of the frequency copy unit 102b is randomized by the frequency scrambler 106a, the same signal is not arranged on the frequency axis as in the case of signal transmission in the transmitters 1 and 1a of the first embodiment.

  FIG. 14 is a diagram for explaining the operation of the receiver 2b when the number of branches information = 4. Specifically, it is a diagram for explaining the operation from the FFT unit 202 to the frequency synthesis unit 210b. . When the number of branches information = 4, the frequency synthesizer 210b adds the result obtained by repeating the synthesis (addition) process of the input signal twice (a signal corresponding to the output of the adder 211-2 shown in FIG. 12). Is output. That is, the signal after frequency synthesis is s0 + s0 + s0 + s0 = 4s0,..., S3 + s3 + s3 + s3 = 4s3.

  13 and 14 show an example in the case where the number of branches information = 4, but compared with the case described in the first embodiment (corresponding to the case where the number of branches = 2), the amount of data that can be transmitted is Although halved, it is less susceptible to fading, interference, and noise. Furthermore, as in the first embodiment, in this embodiment, since the signal on the frequency axis is randomized, no peak occurs in the transmission signal.

  As described above, in the communication apparatus according to the present embodiment, in addition to the function of the transmitter according to the first embodiment, the transmitter designates the number of times of copying when copying a signal in the frequency domain as the number of branches information. It was decided to have a function. In other words, a configuration is adopted in which the number of copy executions can be made variable. Thereby, the number of branches according to the influence of fading, interference, and noise can be selected without causing a peak in the transmission signal. As a result, when the influence of fading, interference, and noise is small (when the transmission path condition is good), the number of branches is reduced and the amount of data to be transmitted is increased. On the other hand, the influence of fading, interference, and noise is When it is large (when the transmission line condition is not good), it is possible to increase the number of branches and control to maintain good communication, and adaptively adapt the communication device according to the transmission line condition. It can also handle the case of use.

Embodiment 3 FIG.
Next, Embodiment 3 will be described. In the first and second embodiments, both communication apparatuses (transmitters and receivers) that perform communication include circuits (PN sequence generators 108 and 208, see FIG. 5) for generating PN sequences. The case where frequency scramble (randomization processing) and frequency descrambling (randomization cancellation processing) are performed using the output PN sequence has been described. On the other hand, in this embodiment, each communication device (transmitter, receiver) holds the PN sequence in a memory or the like, and uses the held PN sequence when executing transmission / reception processing. A communication device to be described will be described.

  FIGS. 15 and 16 are diagrams illustrating configuration examples of the frequency scramblers 106c and 106d included in the transmitter according to the third embodiment. The address control unit 114 is a component necessary for generating a PN sequence. Is also described. The configuration shown in FIG. 15 is applied when the above-described transmitter 1 (see FIG. 1) is modified, and the configuration shown in FIG. 16 uses the above-described transmitter 1a (see FIG. 6). This is applied when deforming. That is, when the transmission apparatus according to the present embodiment is realized based on transmitter 1, frequency scrambler 106 and reset signal generation unit 109 are replaced with frequency scrambler 106c and address control unit 114. When the transmission apparatus according to the present embodiment is realized based on the transmitter 1a, the frequency scrambler 106a and the reset signal generation unit 109 are replaced with the frequency scrambler 106d and the address control unit 114. Moreover, these are applicable also to the transmitter (refer FIG. 10 etc.) of Embodiment 2.

  FIG. 17 is a diagram illustrating a configuration example of the frequency descrambler 206c included in the receiver according to the third embodiment, which is applied when the above-described receiver 2 is modified. In addition, an address control unit 216, which is a component necessary for generating a PN sequence, is also described. That is, by replacing the frequency descrambler 206 and the reset signal generation unit 209 with the frequency descrambler 206c and the address control unit 216, the receiving apparatus of this embodiment is realized. Note that the present invention can also be applied to the receiver 2b (see FIG. 11) of the second embodiment.

  In the communication apparatus (transmitter, receiver) of the present embodiment, the PN sequence memory 113 included in the frequency scramblers 106c and 106d and the PN sequence memory 215 included in the frequency descrambler 206c are generated in advance. Save the PN series. The PN sequence may be generated in advance using a PN sequence generator as shown in FIG. 5, or may be calculated and generated in advance using an external computer or the like. The address control units 114 and 216 control the read addresses of the PN sequence memories 113 and 215 and repeat the same address for each OFDM symbol, so that the same PN sequence is repeatedly output from the PN sequence memories 113 and 215 at the OFDM symbol period. To be.

  When the apparatus configuration of the present embodiment is adopted, the PN sequence generators 108 and 208 shown in FIG. 5 are not required, so that the circuit scale is reduced and the communication apparatus can be simplified.

Embodiment 4 FIG.
Next, the fourth embodiment will be described. In the first to third embodiments, an example in which both communication apparatuses (transmitter and receiver) that perform communication always use the same PN sequence has been described. In this embodiment, a frequency scrambler and a frequency are used. A communication apparatus in which a descrambler executes processing using a specified one from a plurality of PN sequences will be described. Note that in each drawing used in the description, the same components as those described in the previous embodiment are denoted by the same reference numerals. The description thereof is omitted.

  FIGS. 18 and 19 are diagrams illustrating configuration examples of the frequency scramblers 106e and 106f included in the transmitter according to the fourth embodiment, and a reset signal generation unit that is a component necessary for generating a PN sequence. 109 and the address control unit 114 are also described. The frequency scrambler 106e shown in FIG. 18 shows a configuration example when the PN sequence generation unit 108 (see FIG. 5) described in the first embodiment is used. FIG. 19 shows a configuration example when the PN sequence memory 113 (see FIGS. 15 and 16) described in the third embodiment is used. The frequency scrambler 106e has a configuration applicable to the transmitter 1 (see FIG. 1) (that is, a configuration in the case where it is arranged at the subsequent stage of the S / P unit 105), and includes a plurality of multipliers 107. Yes. On the other hand, the frequency scrambler 106f has a configuration applicable to the transmitter 1a (see FIG. 6) (that is, a configuration in the case where it is arranged in the preceding stage of the S / P unit 105), and includes a single multiplier 107. ing.

  The frequency scrambler 106e shown in FIG. 18 includes a plurality of PN sequence generation units (PN sequence generation units 108-1 to 108-N) and a selector 115 as a configuration for generating a PN sequence, and generates a reset signal. Initialized in response to a reset instruction (reset signal) from the unit 109. Each PN sequence generation unit outputs a PN sequence having a different pattern, and the selector 115 sends the PN sequence received from any one PN sequence generation unit to the multiplier 107 in accordance with a PN sequence designation signal input from the outside. Output. The reset signal output from the reset signal generation unit 109 is branched and input to each PN sequence generation unit.

  The frequency scrambler 106f shown in FIG. 19 includes a plurality of PN sequence memories (PN sequence memories 113-1 to 113-N) and a selector 115 as a configuration for generating a PN sequence. Follow the instructions. Each PN sequence memory stores a PN sequence having a different pattern and outputs a PN sequence corresponding to the read address received from the address control unit 114. The selector 115 outputs the PN sequence received from any one PN sequence memory to the multiplier 107 in accordance with the PN sequence designation signal input from the outside. The read address of the PN sequence memory output from the address control unit 114 is branched and input to each PN sequence memory.

  Note that the respective configurations for generating the PN sequences shown in FIGS. 18 and 19 can be interchanged. That is, a configuration applicable to the transmitter 1 may be realized by a PN sequence memory, or a configuration applicable to the transmitter 1a may be realized by a PN sequence generation unit. Also, these frequency scramblers 106e and 106f can be applied to the transmitter shown in the second or third embodiment.

  20 and 21 are diagrams illustrating configuration examples of the frequency descramblers 206e and 206f included in the receiver according to the fourth embodiment, and a reset signal generation unit that is a component necessary for generating a PN sequence. 209 and the address control unit 216 are also described. The frequency descrambler 206e shown in FIG. 20 shows a configuration example when the PN sequence generator 208 (see FIG. 5) described in the first embodiment is used. FIG. 21 shows a configuration example when the PN sequence memory 215 (see FIG. 17) described in the third embodiment is used.

  The frequency descrambler 206e shown in FIG. 20 includes a plurality of PN sequence generators (PN sequence generators 208-1 to 208-N) and a selector 217 as a configuration for generating a PN sequence, and generates a reset signal. 209 is initialized in response to a reset instruction (reset signal). Each PN sequence generation unit outputs a PN sequence having a different pattern, and the selector 217 outputs the PN sequence received from any one of the PN sequence generation units to the multiplier 207 in accordance with a PN sequence designation signal input from the outside. Output. The reset signal output from the reset signal generator 209 is branched and input to each PN sequence generator.

  The frequency descrambler 206f shown in FIG. 21 includes a plurality of PN sequence memories (PN sequence memories 215-1 to 215-N) and a selector 217 as a configuration for generating a PN sequence. Follow the instructions. Each PN sequence memory stores PN sequences having different patterns, and outputs the stored PN sequences. The selector 217 outputs the PN sequence received from any one PN sequence memory to the multiplier 207 in accordance with the PN sequence designation signal input from the outside. The read address of the PN sequence memory output from the address control unit 216 is branched and input to each PN sequence memory.

  The PN sequence designation signal input to the frequency descramblers 206e and 206f is controlled so that the same PN sequence as that used in the communication device (transmitter) on the transmission side is output to the multiplier 207. . Also, these frequency descramblers 206e and 206f can be applied to the receiver shown in the second or third embodiment.

  Thus, in the present embodiment, the PN sequence used for setting / cancellation of randomization in the transmission process and the reception process can be selected from a plurality of PN sequences. As a result, the PN sequence can be easily changed without changing the circuit or software.

Embodiment 5 FIG.
Next, the fifth embodiment will be described. In the previous embodiment, a communication apparatus that performs setting / cancellation of randomization by performing signal sign inversion processing with a frequency scrambler and a frequency descrambler has been described. However, in this embodiment, a plurality of bits of a PN sequence are used. A communication device that transmits and receives a signal whose phase is randomly converted based on the above will be described. Note that in each drawing used in the description, the same components as those described in the previous embodiment are denoted by the same reference numerals. The description thereof is omitted.

  FIG. 22 is a diagram illustrating a configuration example of the frequency scrambler 106g included in the transmitter according to the fifth embodiment, and FIG. 23 illustrates a configuration example of the frequency descrambler 206g included in the receiver according to the fifth embodiment. FIG.

  As shown in the figure, the frequency scrambler 106g provided in the transmitter of this embodiment is obtained by adding a phase conversion unit 116 to the frequency scrambler 106 (see FIG. 1) shown in the first embodiment. There is a configuration example in the case of being arranged in the subsequent stage of the S / P unit 105. The phase converter 116 converts a plurality of bits of the output of the PN sequence generator 108 (PN sequence) into a phase rotation amount and outputs the phase rotation amount (outputs a phase rotation amount corresponding to the value of the plurality of bits). Therefore, multiplier 107 rotates the phase of the signal input from preceding S / P section 105 by the amount of phase rotation output from phase conversion section 116. Here, an example in which the phase of the signal input from the S / P unit 105 is rotated has been described, but the phase of the signal input to the S / P unit 105 may be rotated. In other words, it can be arranged in front of the S / P unit 105. In that case, the frequency scrambler has one multiplier 107.

  Further, the frequency descrambler 206g provided in the receiver of this embodiment is obtained by adding a phase converter 218 to the frequency descrambler 206 (see FIG. 2) shown in the first embodiment. The phase converter 218 converts a plurality of bits of the output of the PN sequence generator 208 (PN sequence) into a phase rotation amount. Therefore, the multiplier 207 rotates the phase of the signal input from the preceding synchronous detection unit 203 by the phase rotation amount output from the phase conversion unit 218. However, the phase conversion unit 218 outputs a phase rotation amount whose rotation direction is opposite to that given by the phase conversion unit 116 of the transmission side communication device (transmitter 1).

  FIG. 24 is a diagram for explaining the operation of the phase converters 116 and 218 when the amount of phase rotation is four, and is output by the PN sequence and the phase converters on both the transmission side and the reception side. The relationship with the amount of phase conversion is shown in the table. In the operation according to FIG. 24, the phase conversion unit 116 (transmitter side) outputs the illustrated phase rotation amount for every 2 bits of the output of the PN sequence generation unit 108. For example, if 2 bits of the PN sequence are “0, 0”, the phase rotation amount is set to 0 and the input signal of the multiplier 107 is not changed. If the 2 bits of the PN sequence are “0, 1”, the phase rotation amount is set to π / 2, and the multiplier 107 rotates the signal by π / 2. Similarly, the phase conversion unit 218 (receiver side) outputs the illustrated phase rotation amount for every 2 bits of the output of the PN sequence generation unit 208. For example, if the 2 bits of the PN sequence are “0, 0”, the phase rotation amount is set to 0 and the input signal of the multiplier 207 is not changed. If the 2 bits of the PN sequence are “0, 1”, the phase rotation amount is set to −π / 2, and the signal is rotated by −π / 2 by the multiplier 207.

  Thus, since the phase rotation given by the transmitter is reversely rotated by the receiver, a signal without phase rotation is restored on the receiving side. The above is a configuration that gives four kinds of phase rotation. For example, three bits of the PN sequence may be used, and eight kinds of phase rotation may be used, and the number of phase rotation amounts can be further increased by using a larger number of bits. It may be increased.

  Here, a case where the phase conversion unit 116 is added to the frequency scrambler 106 to realize the frequency scrambler 106g, and the phase conversion unit 218 is added to the frequency descrambler 206 to realize the frequency descrambler 206g. Although shown, it is not limited to this. That is, the phase conversion unit 116 can be applied to any of the frequency scramblers (frequency scramblers 106a, 106c, 106d, 106e, 106f) shown in the previous embodiment. Similarly, the phase conversion unit 218 can be applied to any of the frequency descramblers already described (frequency descramblers 206c, 206e, 206f). In applying to any of these frequency scramblers and frequency descramblers, a phase conversion unit may be provided between the multiplier and the PN sequence generation unit (or PN sequence memory, selector).

  Thus, in this embodiment, the transmitter performs randomization by rotating the phase of the transmission signal by the rotation amount corresponding to the PN sequence, and the receiver performs the same rotation amount as that given by the transmitter. Therefore, the phase of the received signal is reversely rotated to cancel the randomization. As a result, the randomness of the transmission signal can be increased, so that the peak amplitude can be prevented from occurring in the time waveform even when the number of subcarriers is small.

Embodiment 6 FIG.
Next, the sixth embodiment will be described. In the present embodiment, a communication device (receiver) that performs weighting and adding when adding signals on the frequency axis to which the same data is transmitted will be described. Note that in each drawing used in the description, the same components as those described in the previous embodiment are denoted by the same reference numerals. The description thereof is omitted.

  FIG. 25 is a diagram illustrating a configuration example of a frequency synthesizer 210h included in the receiver according to the sixth embodiment. The frequency synthesizer 210h is obtained by adding a coefficient generator 219 and a plurality of multipliers 220 to the frequency synthesizer 210 (see FIG. 2) shown in the first embodiment. The coefficient generator 219 generates a weighting coefficient, and each multiplier 220 multiplies the input signal to the frequency synthesizer 210h by the weighting coefficient generated by the coefficient generator 219.

  The coefficient generation unit 219 measures the quality of each signal on the frequency axis to which the same data is transmitted, and generates a weight coefficient according to the measurement result. The quality used is “Signal to Noise Power Ratio (SNR)”, “Signal to Interference Power Ratio (SIR)”, “Signal to Noise + Interference Power Ratio (SINR)”. : Signal to Interference + Noise Power Ratio) and “Signal Power”, and any of these may be used.

  Which quality is used may be determined in consideration of performance, noise amount, interference amount, device circuit scale, and the like. SNR, SIR and SINR are advantageous when performance is important. However, since the circuit scale becomes large, if it is necessary to reduce the circuit scale, signal power may be employed.

  As described above, in the receiver according to the present embodiment, when combining received signals, weighting based on the quality of each received signal (received quality for each frequency) is performed. Specifically, a high-quality frequency is multiplied by a large weighting factor, and a low-quality frequency is multiplied by a small weighting factor before being combined. As a result, a signal with a good quality frequency can be dominant (a signal with a poor quality frequency is made small) at the output of the adder 211, so that the effect of being less susceptible to fading, interference, and noise can be obtained.

  In the present embodiment, the case where the frequency synthesizer 210 of the receiver 2 shown in the first embodiment is modified has been described. However, the frequency synthesizer 210b of the receiver 2b shown in the second embodiment (FIG. 12). It is also possible to modify (see). In this case, a weighting factor may be generated from a signal input to each adder 211-1 at the first stage of the frequency synthesizer 210b, and the weighting factor may be multiplied before addition.

Embodiment 7 FIG.
Next, Embodiment 7 will be described. In the present embodiment, a communication device (receiver) that selects and uses a signal having the highest quality among a plurality of signals on the frequency axis to which the same data is transmitted and a signal obtained by combining them. ). Note that in each drawing used in the description, the same components as those described in the previous embodiment are denoted by the same reference numerals. The description thereof is omitted.

  FIG. 26 is a diagram illustrating a configuration example of the frequency synthesizer 210i included in the receiver according to the seventh embodiment. The frequency synthesizer 210i is obtained by adding a selection signal generator 221 and a plurality of pre-stage selectors 222 and post-stage selectors 223 to the frequency synthesizer 210 (see FIG. 2) shown in the first embodiment. The selection signal generation unit 221 outputs selection signals for the front stage selector 222 and the rear stage selector 223. The pre-stage selector 222 and the post-stage selector 223 output the selected (designated) side input according to the selection signal generated by the selection signal generation unit 221.

  The selection signal generation unit 221 measures the quality of each signal on the frequency axis to which the same data is transmitted. The quality may be any quality that can be used by the coefficient generation unit 219 included in the frequency synthesis unit 210h of the sixth embodiment. Which quality is used is the same as that of the frequency synthesis unit 210h of the sixth embodiment. You just have to decide. First, the selection signal generation unit 221 generates a selection signal for selecting the better quality signal (frequency) transmitted with the same data, and outputs the selection signal to the upstream selector 222. Further, the difference in quality of signals transmitted with the same data is calculated, and when this difference is less than the threshold value, the output of the adder 211 is output. A selection signal for selection is generated and output to the subsequent selector 223. As a result, the signal having the higher quality is output from the front stage selector 222, and the signal having the higher quality selected by the adder 211 or the signal having the higher quality selected by the front stage selector 222 is output from the rear stage selector 223. Is output.

  If the quality of each frequency at which the same data is transmitted is comparable, the communication performance is improved by adding these. However, if the quality of one of them is extremely bad, adding them will deteriorate the communication performance. Therefore, in the frequency synthesizer 210i provided in the receiver of the present embodiment, the difference in the quality of the frequency at which the same data is transmitted is compared with the threshold value, and the added signal or the signal with the better quality Either is selected by the subsequent selector 223. Here, the threshold value is a parameter that determines how much difference is added, and may be determined in advance by simulation or the like at the time of design, or may be determined by adjusting the device at the time of installation or the like.

  Here, by changing the operation of the coefficient generation unit 219 in the frequency synthesis unit 210h (see FIG. 25) shown in the sixth embodiment, the same operation as that of the frequency synthesis unit 210i of the present embodiment can be realized. . That is, in this case, the coefficient generation unit 219 measures the difference in quality between frequencies at which the same data is transmitted, and outputs a coefficient 0 or 1 to the multiplier 220. If both of the signals input to the adder 211 have a coefficient of 1, an added signal is output. If a coefficient of a signal having a lower quality is 0, a signal having a higher quality is output. The same output as the frequency synthesizer 210i of the present embodiment is obtained. Note that the configuration of the present embodiment (see FIG. 26) can be realized with a smaller circuit scale because the multiplier 220 is unnecessary and can be configured with only a selector.

  As described above, in the receiver according to the present embodiment, since the signal having the best quality is selected from the signals before combining and the signals after combining, the frequency at which the same data is transmitted is selected. Even when the difference in quality is large, an effect that good communication characteristics can be obtained can be obtained.

Embodiment 8 FIG.
Next, an eighth embodiment will be described. In this embodiment, a communication device (transmitter) that can set (select) whether to execute frequency scramble (randomization processing) in the frequency scrambler will be described. Note that in each drawing used in the description, the same components as those described in the previous embodiment are denoted by the same reference numerals. The description thereof is omitted.

  FIG. 27 is a diagram illustrating a configuration example of the frequency scrambler 106j provided in the transmitter according to the eighth embodiment. The frequency scrambler 106j is obtained by adding a selector 117 to the frequency scrambler 106 (see FIG. 1) shown in the first embodiment. The selector 117 receives A and B2 system signals, that is, a PN sequence (A system) and a fixed value 0 (B system), and according to a control signal (ON / OFF signal) input from the outside, the A system , B Select or output one of the B systems. When the control signal indicates ON, the selector 117 selects the PN sequence. When the control signal indicates OFF, the selector 117 selects the fixed value 0. The operation when the PN sequence of A is selected is as described in the first embodiment. On the other hand, when B is selected, 0 is input to the multiplier 107, and as described in the first embodiment, the input signal of the multiplier 107 becomes the output signal of the multiplier 107 as it is. That is, the ON / OFF signal is a signal for instructing to select B when frequency scrambling is not performed.

  FIG. 28 is a diagram for explaining the operation of the communication apparatus according to the eighth embodiment, and shows a configuration example of signals to be transmitted and received. As shown in the figure, the communication device (transmitter, receiver) of the present embodiment transmits and receives a signal in a format including, for example, a preamble (Pre) and a payload (Payload (1), Payload (2)). Usually, a known random pattern is set in Pre. User information data is set in Payload (1) and Payload (2). FIG. 28 is an example in which frequency diversity is applied only to Payload (1). In this case, the ON / OFF signal is input so as to be A at the timing of Payload (2) and B otherwise, and only Payload (1) is randomized.

  FIG. 27 shows a configuration example in which an ON / OFF selector (selector 117) is added to the frequency scrambler 106 shown in the first embodiment, but the other frequency scrambler (frequency scrambler 106a) described above. , 106c, 106d, 106e, 106f, 106g). Similarly, in these cases, the selector 117 may be provided between the PN sequence generator 108, the PN sequence memory 113, and the multiplier 107.

  As described above, the communication apparatus according to the present embodiment employs a configuration including a selector for selecting whether to apply frequency diversity. As a result, even when a signal to which frequency diversity is applied and a signal to which frequency diversity is not applied coexist, it is possible to prevent a peak amplitude from occurring in the time waveform of the signal to which frequency diversity is applied. That is, for example, when Payload (1) shown in FIG. 28 is a signal of user # 1, Payload (2) is a signal of user # 2, and user # 2 is a user who does not perform frequency diversity, If the signal is randomized, the user # 2 cannot cancel the randomization and cannot restore the data. However, if the configuration of the present embodiment is adopted, even if such frequency diversity application is mixed, the signal of user # 2 can be prevented from being randomized. Can be received. That is, the configuration of the present embodiment is useful for a base station that performs simultaneous communication with a plurality of communication apparatuses.

Embodiment 9 FIG.
Subsequently, Embodiment 9 will be described. In the present embodiment thus far, an example in which the multicarrier signal is an OFDM signal has been described, but the present invention can also be applied to communication using a single carrier OFDM signal (SC-OFDM signal). Note that in each drawing used in the description, the same components as those described in the previous embodiment are denoted by the same reference numerals. The description thereof is omitted.

  FIG. 29 is a diagram illustrating a configuration example of a transmitter according to the ninth embodiment, and the transmitter 1k transmits an SC-OFDM signal to a facing communication device (receiver). As illustrated, the transmitter 1k is obtained by replacing the frequency copy unit 102 and the S / P unit 105 of the transmitter 1 (see FIG. 1) described in Embodiment 1 with an FFT unit 118 and a frequency copy unit 102k. is there.

  FIG. 30 is a diagram illustrating a configuration example of a receiver according to the ninth embodiment, and the receiver 2k receives an SC-OFDM signal transmitted from an opposing communication device (transmitter). As illustrated, the receiver 2k is obtained by adding an IFFT unit 224 to the receiver 2 (see FIG. 2) described in the first embodiment.

  Note that in this embodiment, a case where the transmitter 1k and the receiver 2k are realized by modifying the transmitter 1 and the receiver 2 described in Embodiment 1 will be described. All other transmitters and receivers can be modified in the same manner.

  In the transmitter 1k, the FFT unit 118 performs FFT on the output signal of the mapping unit 101 and converts it to a signal on the frequency axis. Although not shown, the mapping unit 101 also performs filtering processing. Unlike the frequency copy units shown in the previous embodiment, the frequency copy unit 102k has input / output parallel signals (see FIG. 31).

  FIG. 31 is a diagram illustrating a configuration example of the frequency copy unit 102k. The frequency copy unit 102k includes a parallel / serial conversion unit (P / S unit) 119, a frequency copy execution unit 120, and a serial / parallel conversion unit (S / S). P part) 121 is provided. The P / S unit 119 converts the parallel signal received from the FFT unit 118 into a serial signal. The frequency copy execution unit 120 performs the same processing as the frequency copy unit 102 or 102b described above on the P / S unit 119 output signal to copy the input signal. The internal configuration of the frequency copy execution unit 120 is the same as that of the frequency copy unit 102 or 102b (see FIGS. 1 and 10). The S / P unit 121 converts the serial signal output from the frequency copy execution unit 120 into a parallel signal.

  In the receiver 2k, the IFFT unit 224 performs an IFFT on the output signal of the frequency synthesis unit 210 to return it to a time waveform. Although not shown, the demapping unit 213 also performs processing such as frequency synchronization, timing synchronization, and carrier wave recovery for demodulation.

  As described above, each method described in the previous embodiment can also be applied to the case where the multicarrier signal is an SC-OFDM signal. When performing frequency diversity in communication using the SC-OFDM signal, the peak amplitude is used. Can be prevented.

Embodiment 10 FIG.
Subsequently, Embodiment 10 will be described. In this embodiment and the following embodiments, a communication system using the communication apparatus (transmitter, receiver) shown in each of the previous embodiments will be described.

  FIG. 32 is a diagram showing an example of a communication system configured by the communication apparatus according to the present invention. The communication system shown in FIG. 32 includes a plurality of communication devices (here, three communication devices 3). Each communication device 3 has the same configuration, and includes a transmitter 1 and a receiver 2, respectively. The transmitter 1 and the receiver 2 are the transmitter 1 and the receiver 2 described in the first embodiment. In FIG. 32, as an example, the case where the transmitter 1 and the receiver 2 described in the first embodiment constitute the communication device 3 is shown, but the transmitter and the receiver that constitute the communication device 3 are Any of the transmitters and receivers described in the first to ninth embodiments may be used. FIG. 32 shows an example in which radio is used as a communication medium, and each communication device 3 is connected via an antenna. However, the present invention is not limited to the wireless communication medium. For example, in the case of power line communication, each communication device 3 is connected via a power line.

  As described above, in the communication system of the present embodiment, each communication device 3 uses the transmitter 1 and the receiver 2 described in the previous embodiment, so that the same data is copied so as to be transmitted at different frequencies. This output is randomized and no peak occurs in the time waveform. Therefore, the output power of each communication device 3 can be increased, and good communication quality can be maintained even when the distance between the communication devices is long.

  Moreover, as a communication system, it may be necessary to arrange communication devices densely. For example, when a communication device is arranged on a utility pole or the like, there are restrictions on the arrangement position. In such a system, interference between communication devices becomes a problem, but communication by the communication device 3 that constitutes the communication system of the present embodiment is less susceptible to the influence (interference) of other communications. Even if there is, good communication can be maintained.

  Further, even in a case where fading of the transmission path is severe as in mobile communication, communication by the communication device 3 is not easily affected by fading, and thus good communication can be maintained even in such a case.

  Further, even in the case where there is a large noise at some frequencies on the transmission line as in power line communication, the communication by the communication device 3 is not easily affected by the noise. Communication can be maintained.

Embodiment 11 FIG.
Next, Embodiment 11 will be described. FIG. 33 is a diagram illustrating a configuration example of the communication system according to the eleventh embodiment. Each communication device 3b configuring the communication system includes the transmitter 1b and the receiver 2b described in the second embodiment. And a quality control unit 31 that generates the branch number information and outputs the branch number information to the transmitter 1b and the receiver 2b. In FIG. 33, the communication device 3b including the transmitter 1b and the receiver 2b is shown as an example. Of the other transmitters and receivers described in the third to ninth embodiments, the number of branches information is shown. It is also possible to replace it with a device that executes a corresponding process (that is, a transmitter having the frequency copy unit 102b and a receiver having the frequency synthesis unit 210b).

  In the communication device 3b shown in FIG. 33, the transmitter 1b and the receiver 2b change the frequency copy number according to the branch number information from the quality control unit 31. The method for changing the frequency copy number is as described above.

  In the communication system, various types of data such as user data, control data, and broadcast data are transmitted. Here, depending on the type of each data, communication quality with very high accuracy may be required. Conversely, it may be more important that the amount of data that can be transmitted is larger than the high communication quality.

  Therefore, the quality control unit 31 generates branch number information according to the required quality of each data. That is, control is performed so that the number of branches is increased when high quality communication is required, and the number of branches is decreased when high quality communication is not required.

  As described above, according to the present embodiment, the number of branches corresponding to the required quality of data is used, so that it is possible to realize a communication system with good quality and a large amount of data that can be transmitted.

Embodiment 12 FIG.
Next, the twelfth embodiment will be described. FIG. 34 is a diagram illustrating a configuration example of a communication system according to the twelfth embodiment, and each communication device 3b ′ configuring the communication system is a modification of the communication device 3b described in the eleventh embodiment. That is, the communication device 3b ′ according to the present embodiment is obtained by replacing the quality control unit 31 of the communication device 3b described above with a quality control unit 31b, and a reception signal is input to the quality control unit 31b. It is configured. Thereby, in the communication system of this Embodiment, each communication apparatus 3b 'produces | generates the number information of branches according to the state of a transmission line, and communicates.

  The state of the transmission line is determined by the magnitude of fading, the amount of noise, the amount of interference, etc., and is not constant. The quality control unit 31b observes these states from the received signal and determines the state of the transmission path. Then, the quality control unit 31b increases the branch number information when the state of the transmission line is bad, and decreases it when the state of the transmission line is good. The greater the number of branches, the greater the resistance to fading, interference, and noise, so that good communication can be maintained even when the state of the transmission path deteriorates. Conversely, the smaller the number of branches, the greater the amount of data that can be transmitted. Therefore, when the transmission path condition is improved, a larger amount of data can be transmitted.

  In addition, as another method for the quality control unit 31b to observe the state of the transmission path, the quality can be adjusted by using the error rate of the reception data generated by the receiver 2b, SNR, SIR, SINR, signal power, etc. You may observe it. In this case, a signal (such as the received data error rate, SNR, etc.) necessary for observing the transmission path state may be passed from the receiver 2b to the quality control unit 31b.

Embodiment 13 FIG.
Next, Embodiment 13 will be described. FIG. 35 is a diagram illustrating an example of a frame format of a communication system in which branch number information is transmitted using a broadcast channel (BCH). The BCH is a communication channel for notification transmitted by a control station called a base station or a master (hereinafter referred to as a base station), and information such as a unique number of the base station and a frame number is transmitted to each communication device. This is a communication channel for notification. By notifying this channel with the number of branches information, a communication apparatus that is newly starting communication can know the number of branches used in the communication system by receiving the BCH. Therefore, it is not necessary to newly provide another communication channel for the number of branches information, the frequency utilization efficiency is improved, and each communication device does not need to receive a new communication channel separately. Can be prevented from increasing.

Embodiment 14 FIG.
Subsequently, Embodiment 14 will be described. FIG. 36 is a diagram showing an example of a frame format in which the PN sequence is changed for each user. “Payload (1)” shown in the figure is data of communication device # 1 (user # 1), “Payload (2)” is data of communication device # 2 (user # 2), and each communication device is in Payload. This shows that different PN sequences (PN (1), PN (2)) are used. A communication system using a large number of PN sequences is more confidential than a communication system using a single PN sequence, and wiretapping and information leakage are less likely to occur. That is, according to the present embodiment, it is possible to realize a communication system that does not generate peak amplitude and that is highly reliable.

Embodiment 15 FIG.
Next, the fifteenth embodiment will be described. FIG. 37 is a diagram showing an example of a frame format in which the PN sequence is changed for each base station. The “Pre (1)” and “Pre (2)” shown in the figure are the preambles of the communication devices # 1 and # 2, respectively, and “CCH (1)” and “CCH (2)” are the communication devices # 1 and # 2, respectively. The control channels “Payload (1)” and “Payload (2)” are the payloads of the communication apparatuses # 1 and # 2, respectively. Communication apparatuses # 1 and # 2 are base stations, and CCH (Control Channel) is a channel for transmitting control data.

  Communication apparatuses other than the base station in the communication system first search for a connection destination base station when communication is started. At this time, the communication apparatus looks at the data in the CCH and determines whether or not the base station is desired. In the communication system of the present embodiment, the PN sequence is changed for each base station. Therefore, if the PN sequence used by the desired base station is set in advance, the CCH of the undesired base station is used. Since different PN sequences are received, this is not received erroneously.

  That is, according to the present embodiment, it is possible to realize a communication system that does not generate a peak amplitude and that can avoid erroneous connection at the start of communication.

  Note that FIG. 37 shows an example in which the communication apparatuses # 1 and # 2 perform frequency scrambling only during CCH transmission. Of course, frequency scrambling can also be applied to transmissions other than CCH. It is.

Embodiment 16 FIG.
In addition, as one of communication systems using the communication apparatus according to the present invention, frequency diversity is applied only to a communication channel that requires noise resistance performance such as a control channel or a modulation scheme that is resistant to noise such as BPSK. A configuration is also conceivable.

  Frequency diversity is strong against fading, interference, and noise, but reduces the amount of data that can be transmitted. Therefore, by limiting the application of frequency diversity only to the control channel, a highly stable communication system can be realized without reducing the amount of data that can be transmitted. Furthermore, a highly stable communication system can be realized without greatly reducing the amount of data that can be transmitted by performing only a modulation scheme that is resistant to noise such as BPSK.

Embodiment 17. FIG.
Next, Embodiment 17 will be described. FIG. 38 is a diagram for explaining the communication system according to the seventeenth embodiment. In the communication system of the present embodiment, the communication device on the transmission side transmits the transmission power of the surplus frequency as 0. FIG. 38 shows an example of a spectrum before frequency scramble processing in the communication system of the present embodiment. For example, when the number of frequencies is 15 and the number-of-branch information = 3, three sets of s0, s1, s2, and s3 can be transmitted, leaving three frequencies (15-4 × 3 = 3). In this case, in this embodiment, the transmission power of these remaining frequencies is set to zero.

  In a communication system, the same frequency is repeatedly reused at a distance away in order to effectively use the frequency (frequency reuse). However, frequency reuse may cause unexpectedly large interference to other communications performed at a long distance. According to the present embodiment, the transmission power of the surplus frequency is set to 0, so that the effect of reducing interference with other communications can be obtained in frequency reuse.

Embodiment 18 FIG.
Subsequently, an eighteenth embodiment will be described. FIG. 39 is a diagram for explaining the communication system according to the eighteenth embodiment. In the communication system according to the present embodiment, the communication device on the transmission side performs communication using all frequencies assigned to the system. For example, under the same conditions as in the seventeenth embodiment (the number of frequencies is 15, the number of branches information = 3), three frequencies remain. In this case, in this embodiment, three of s0, s1, s2, and s3 are selected, assigned, and transmitted to these remaining frequencies. As a method of selecting three, you may select in order, such as s0, s1, s2, and if there are items that contain important information in s0, s1, s2, s3, give priority to them. May be selected.

  According to the present embodiment, since the surplus frequency is used as much as possible, it is difficult to be affected by fading, interference, and noise, and an effect of maintaining good communication can be obtained.

  Note that the communication systems shown in Embodiments 10 to 18 are not limited to multicarrier signals, and both OFDM signals and SC-OFDM signals can be applied.

  As described above, the transmitter, the receiver, and the communication device according to the present invention are useful for multicarrier communication, and particularly suitable for a communication device that performs multicarrier communication to which frequency diversity is applied while suppressing generation of peak amplitude. ing.

1, 1a, 1b Transmitter 2, 2b Receiver 3, 3b, 3b 'Communication device 31, 31b Quality control unit 101 Mapping unit 102, 102b, 102k Frequency copy unit 103 Memory 104, 115, 117, 217, 222, 223 , 302 Selector 105, 121 Serial / parallel converter (S / P unit)
106, 106a, 106c, 106d, 106e, 106f, 106g, 106j Frequency scrambler 107, 204, 207, 220 Multiplier 108, 108-1, 108-N, 208, 208-1, 208-N PN sequence generator 109 Reset signal generation unit 110, 224 IFFT unit 111 Analog TX unit 112 Selection control unit 113, 113-1, 113-N, 215, 215-1, 215-N PN sequence memory 114, 216 Address control unit 116, 218 Phase Conversion unit 118, 202 FFT unit 119, 212 Parallel / serial conversion unit (P / S unit)
120 Frequency copy execution unit 201 Analog RX unit 203 Synchronous detection unit 205 Transmission path estimation unit 206, 206c, 206e, 206f, 206g Frequency descrambler 209 Reset signal generation unit 210, 210b, 210h, 210i Frequency synthesis unit 211, 211-1 , 211-2, 211-3 adder 213 demapping unit 219 coefficient generation unit 221 selection signal generation unit 301 delay circuit 303 exclusive OR circuit 304 initial value memory

Claims (32)

A transmitter for transmitting a multicarrier signal,
Frequency copy means for copying the same data in the frequency domain;
Frequency scramble means for randomizing the output signal from the frequency copy means;
Frequency time conversion means for converting an output signal from the frequency scramble means into a time domain signal;
Equipped with a,
The frequency scramble means includes
From an initial value memory storing an initial value of a PN sequence, a logic circuit that generates a PN sequence based on the initial value of the PN sequence, and a reset signal generating unit that generates a reset signal for initializing the logic circuit PN sequence generation means for initializing a PN sequence in units of transmission symbols and repeatedly generating a PN sequence of the same pattern,
With
Transmitter characterized that you perform a random process based on the PN sequence generated by the PN sequence generation unit.   The transmitter according to claim 1, wherein the frequency copying unit performs copying so that an interval between frequencies transmitting the same data is maximized. The frequency scramble means includes
A plurality of the PN sequence generation means, and each of the PN sequence generation means generates a different PN sequence,
In the randomization process in accordance with an instruction from the external transmitter of claim 1 or 2, characterized by using the generated PN sequence in any one of the plurality of PN sequence generation unit . A transmitter for transmitting a multicarrier signal,
Frequency copy means for copying the same data in the frequency domain;
Frequency scramble means for randomizing the output signal from the frequency copy means;
Frequency time conversion means for converting an output signal from the frequency scramble means into a time domain signal;
With
The frequency scramble means includes
Performs address specified for previously generated in advance PN sequence memory for storing a PN sequence with, and the PN sequence memory, the address control unit for outputting information corresponding address is stored in an area indicated externally, Ri Tona , PN sequence output means you repeatedly output PN sequences of the same pattern in transmission symbol unit,
With
Shin machine feed you and the client performs randomizing processing based on the PN sequence outputted from the PN sequence output unit. The frequency scramble means includes
A plurality of the PN sequence output means, and each of the PN sequence output means outputs a different PN sequence,
5. The transmitter according to claim 4 , wherein the randomizing process uses a PN sequence output from any one of the plurality of PN sequence output means in accordance with an instruction from the outside. When configuring a communication device that operates as a base station capable of communicating with a plurality of user stations,
The transmitter according to claim 3 or 5 , wherein the randomization process is executed using a different PN sequence for each user station of a communication partner. When configuring a communication device that operates as a user station that can communicate with a plurality of base stations,
The transmitter according to claim 3 or 5 , wherein the randomization process is executed using a different PN sequence for each base station of a communication partner. Said frequency scrambling means, based on the PN sequence, out of the signal output from the frequency copying means any of claims 1 to 7, by reversing the sign of the portion of the signal, characterized in that randomized A transmitter according to any one of the above. Said frequency scrambling means, the according amount of rotation based on the PN sequence, wherein one of the signal output from the frequency copying means to rotate the phase of a portion of the signal, characterized in that randomized claim 1 The transmitter according to any one of 8 . The transmitter according to any one of claims 1 to 9 , wherein the frequency scramble means executes the randomization process for transmission of a specific channel or transmission to which a specific modulation scheme is applied. . The transmitter according to any one of claims 1 to 10 , wherein the frequency copying unit employs a configuration capable of changing the number of times of copying the same data. The frequency copy means increases the number of copy executions when high-quality communication is required, and decreases the number of copy executions when high-quality communication is not required. the transmitter according to claim 1 1. It said frequency copying means, the transmission of Claim 1 1, when a bad transmission channel state is to increase the number of times the copy execution, when the transmission path condition is good, characterized in that to reduce the number of times the copy execution Machine. When configuring a communication device that operates as a base station capable of communicating with a plurality of user stations,
Using control channel for transmitting control information transmitter of claim 1 1, 1 2 or 1 3, wherein the notifying the copy number of executions to each user station of the communication partner. It said frequency copying means, of the input signal, the transmitter according to any one of claims 1 to 1 4, characterized in that it has a function of copying the portion of the signal only. Wherein the outputs from the frequency copier, the available frequency data is not mapped, according to any one of claims 1 to 1 5, characterized in that transmitting the signal power is set to 0 Transmitter. The frequency copying means continues copying data until there is no free frequency when there is an empty frequency to which no data is mapped at that time after the same data has been copied a specified number of times. The transmitter according to any one of claims 1 to 15 . The transmitter according to any one of claims 1 to 17, characterized in that transmitting an OFDM signal. The transmitter according to any one of claims 1 to 17, characterized by transmitting a single-carrier OFDM signal. A receiver that receives a multicarrier signal transmitted by an opposing communication device that performs data copying and randomization in the frequency domain,
Time-frequency conversion means for converting a time-domain received signal into a frequency-domain received signal;
Frequency descrambling means for executing processing (randomization cancellation processing) opposite to randomization processing executed when the opposite communication device transmits a signal to the output signal from the time frequency conversion means;
Of the output signals from the frequency descrambling means, signal synthesizing means for synthesizing signals including the same data;
Equipped with a,
The frequency descrambling means includes:
From an initial value memory storing an initial value of a PN sequence, a logic circuit that generates a PN sequence based on the initial value of the PN sequence, and a reset signal generating unit that generates a reset signal for initializing the logic circuit PN sequence generation means for initializing a PN sequence in units of transmission symbols and repeatedly generating a PN sequence of the same pattern,
With
Receiver characterized that you perform a random decryption process based on the PN sequence generated by the PN sequence generation unit. The frequency descrambling means includes:
A plurality of the PN sequence generation means, and each of the PN sequence generation means generates a different PN sequence,
In randomized cancellation process in accordance with an instruction from the external receiver of claim 2 0, characterized by using a PN sequence generated by any one of the plurality of PN sequence generation unit . A receiver that receives a multicarrier signal transmitted by an opposing communication device that performs data copying and randomization in the frequency domain,
Time-frequency conversion means for converting a time-domain received signal into a frequency-domain received signal;
Frequency descrambling means for executing processing (randomization cancellation processing) opposite to randomization processing executed when the opposite communication device transmits a signal to the output signal from the time frequency conversion means;
Of the output signals from the frequency descrambling means, signal synthesizing means for synthesizing signals including the same data;
With
The frequency descrambling means includes:
Performs address specified for previously generated in advance PN sequence memory for storing a PN sequence with, and the PN sequence memory, the address control unit for outputting information corresponding address is stored in an area indicated externally, Ri Tona , PN sequence output means you repeatedly output PN sequences of the same pattern in transmission symbol unit,
With
Receiver device you and executes a random decryption process based on the PN sequence outputted from the PN sequence output unit. The frequency descrambling means includes:
A plurality of the PN sequence output means, and each of the PN sequence output means outputs a different PN sequence,
In randomized cancellation process in accordance with an instruction from the external receiver of claim 2 2, characterized in that the use of PN sequence outputted from any one of the plurality of PN sequence output means . 3. The frequency descrambling unit, based on the PN sequence, reverses the sign of some of the signals output from the time-frequency conversion unit to cancel randomization. 0-2 3 the receiver of any one of. The frequency descrambling means cancels randomization by reversely rotating the phase of some of the signals output from the time-frequency conversion means according to the rotation amount based on the PN sequence. the receiver according to claim 2 0-2 3. The signal synthesizing unit selects any one of the received signals including the same data and a synthesized signal obtained by synthesizing the received signals based on the quality of the received signals, and outputs the selected signal. the receiver according to any one of claims 2 0-25, characterized in that. Said signal combining means, receiver according to claim 2 0-26, wherein the synthesis by adding the signals respectively containing the same data. Said signal combining means, receiver according to claim 2 0-26, characterized in that the signals respectively containing the same data are synthesized by weighting addition based on the reception quality. The signal synthesizing unit executes a plurality of types of synthesizing processes in which the number of signals to be synthesized is different from each other, and outputs any one of the obtained synthesized signals and the pre-combined signals input to itself to the external the receiver according to any one of claims 2 0-28, characterized in that the output in accordance with an instruction from. The receiver according to any one of claims 2 0-29, characterized in that for receiving an OFDM signal. The receiver according to any one of claims 2 0-29, characterized in that receiving a single-carrier OFDM signal. A transmitter according to any one of claims 1 to 19 ,
Of the claims 2 0-3 1 according to any one receiver, a receiver that performs the processing of the processing and inverse frequency copier and frequency scrambling means constituting the transmitter performs,
A communication apparatus comprising:

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