JP4279646B2 - Communication device - Google Patents

Description

  The present invention relates to a communication method and a communication apparatus, and more particularly to a control technique of a control signal and a subsequent data signal.

  In recent years, the number of users seeking to increase the speed of a wireless communication system has increased, and a multi-carrier transmission system has attracted attention as one of communication systems capable of realizing an increase in speed and capacity.

  The multicarrier transmission method is a transmission method in which information signals are transmitted in parallel by frequency division multiplexing using a plurality of narrow bandwidth subcarriers arranged at a certain frequency interval. FIG. 12 shows the transmission spectrum (200, 202) and propagation path variation when performing high-speed transmission by single carrier transmission (FIG. 12A) and multicarrier transmission (FIG. 12B). It is a figure which shows a received spectrum (201, 203), respectively. As shown in FIG. 12A, when high-speed transmission is performed by single carrier transmission, the frequency characteristics of the power spectrum are not flat over the entire frequency band due to the influence of frequency selective fading (see spectrum 201). This corresponds to the occurrence of intersymbol interference in the time domain, and causes a significant deterioration in transmission quality. On the other hand, in multicarrier transmission, even in a frequency selective fading environment, the channel fluctuation of each subcarrier can be regarded as uniform fading (spectrum 203), and the influence of frequency selective fading is reduced. .

  Also, as shown in FIG. 12, in multicarrier transmission, the received power of each subcarrier (or received SNR: Signal to Noise Power Ratio and received SINR: Signal to Interference plus Noise Power Ratio) is different. Therefore, instead of assigning modulation parameters such as transmission power and the number of modulation levels to all subcarriers in common, an adaptive modulation method (subcarrier adaptive modulation method) that gives appropriate modulation parameters for each subcarrier according to the propagation path conditions. ) Can be used for highly efficient communication.

  Non-patent document 1 exists as an examination example using the subcarrier adaptive modulation scheme as described above. An outline of this multilevel transmission power control method is shown in FIG.

  As shown in FIG. 13, the multilevel transmission power control method, which is a kind of subcarrier adaptive modulation method, has a modulation BER number corresponding to a required BER (Bit) according to the modulation multivalue number selected for each subcarrier. In this method, transmission power control is performed in multiple stages so as to satisfy (Error Rate). For example, when the reception (propagation path) status of the subcarrier 210 in FIG. 13 is good, 64QAM (Quadrature Amplitude Modulation), which is a high-rate modulation multilevel number, is selected as the modulation multilevel number in the subcarrier 210. Then, transmission power control is performed so that 64QAM is received with power satisfying the required BER (FIG. 13: reference numeral 211). Further, for subcarriers with extremely poor propagation path conditions, as shown by subcarriers 212 and 213 in FIG. 13, by making a carrier hole without allocating power to subcarriers, this subcarrier error is prevented. It is possible to reduce useless transmission power consumption. In the description of Non-Patent Document 1, it is clarified that by using multilevel transmission power control in this way, it is possible to effectively reduce transmission power while sufficiently extracting the capability of the adaptive modulation scheme.

  Here, FIG. 14 and FIG. 15 show an outline of a frame configuration example and a reception power spectrum in the subcarrier adaptive modulation scheme described so far, respectively. As shown in FIGS. 14 and 15, in the subcarrier adaptive modulation scheme, the signal for notifying the pilot signal 220 for channel compensation and the modulation multilevel information used in each subcarrier of the data signal. The modulation information signal 221 and the data signal 222 constitute one frame. In such a frame, there is usually a common modulation scheme (a low-rate modulation scheme excellent in noise resistance, such as BPSK) used in all subcarriers of the pilot signal 220 and the modulation information signal 221. As shown in the spectrum 223 of FIG. 15, the transmission power is controlled so that the reception power is constant for all subcarriers. However, the modulation multi-level number used in the pilot signal 220 and the modulation multi-level number used in the modulation information signal 221 may be different.

  In addition, as described above, in the data signal 222, the modulation multilevel number is selected for each subcarrier according to the propagation path condition, and the transmission power is set so that each selected modulation multilevel number satisfies the required BER. Control is performed (spectrum 224 in FIG. 15). Therefore, transmission power control different from that of the pilot signal 220 and the modulation information signal 221 provided before the data signal 222 is performed.

  Next, FIG. 16 shows a configuration of a transceiver when the frame shown in FIG. 14 is targeted. As shown in FIG. 16, in a transmitter 252 in a general transceiver, first, the modulation scheme / transmission power determination unit 242 uses the modulation multi-level number and transmission power used for data transmission, and the pilot signal / modulation information signal. The transmission power is determined in consideration of the propagation path condition of each subcarrier. At this time, a modulation information signal representing modulation multi-level information used in each subcarrier of the data signal is also generated.

  Next, in the modulation unit 243, the transmission data transmitted from the upper MAC (Media Access Control) layer 241 is modulated by the previously determined modulation multi-value number of the data signal, and in the pilot signal generation unit 244 A pilot signal is generated. The power control unit 245 controls transmission power of the pilot signal, modulation information signal, and data signal generated in this way. Here, the pilot signal and the modulation information signal are power controlled so that the received power is constant (see spectrum 223 in FIG. 15), and the modulation multi-level number of each subcarrier satisfies the required BER for the data signal. The power is controlled as shown (see spectrum 224 in FIG. 15).

  Next, the signal is serial-parallel converted (serial-parallel converter S / P 247 in FIG. 16), converted from a frequency-domain signal to a time-domain signal by IFFT (Inverse Fast Fourier Transform) circuit 248, and then RF (Radio Frequency). ) The signal is transmitted from the antenna via the circuit 250 or the like.

  On the other hand, at the time of reception, the signal received by the antenna is input to the receiver 251 via the RF circuit 250 and the like, and is converted from a time domain signal to a frequency domain signal by an FFT (Fast Fourier Transform) circuit 230. Later, this signal is converted into a serial signal by a parallel / serial converter (P / S) 231, and separated into a pilot signal, a modulation information signal, and a data signal by a signal separation unit 232. Next, the pilot signal is input to the phase fluctuation estimation unit 233, and the amount of phase fluctuation due to the influence of the propagation path is estimated. The phase fluctuation amount estimated here is input to the phase fluctuation compensation unit 234, and the phase fluctuation of the pilot signal, modulation information signal, and data signal is compensated for each subcarrier.

  Next, the pilot signal after phase fluctuation compensation is input to reference amplitude calculation section 235, and the reference amplitude necessary for demapping is calculated for each subcarrier using the received amplitude of the pilot signal. After performing the demapping by inputting the reference amplitude calculated here and the phase-compensated modulation information signal to the demapping unit 239 at the same time, and comparing the received amplitude of the reference amplitude and the modulation information signal for each subcarrier. The Viterbi decoder 240 decodes the modulated multilevel information used in each subcarrier.

  In addition, unlike a pilot signal or a modulation information signal, a data signal is subjected to transmission power control for each subcarrier based on the selected modulation multi-level number. Therefore, when calculating a reference amplitude necessary for demapping, In addition, it is necessary to correct the reference amplitude according to the number of modulation levels of each subcarrier. Therefore, the previously obtained modulation multilevel number information is input to the amplitude ratio calculation unit 236, and the required amplitude is satisfied for the pilot signal satisfying the required BER and the modulation multilevel number selected for each subcarrier of the data signal. The ratio of the amplitude that satisfies the BER is required. The reference amplitude correction unit 237 multiplies the received amplitude of each subcarrier of the pilot signal by the amplitude ratio obtained in this way, thereby correcting the amplitude ratio and calculating the reference amplitude used for data signal demapping. Is done. Furthermore, the reference amplitude obtained by the above method and the received amplitude of the data signal are input to the demapping unit 239, and by comparing these amplitudes, demapping is performed that compensates for the influence of the channel fluctuation, The subsequent Viterbi decoder 240 decodes the data and then sends it to the upper layer MAC layer 241.

“Yoshinori et al.,“ Characteristics of Multilevel Transmission Power Control Application in OFDM Subcarrier Adaptive Modulation System ””, IEICE Technical Report RCS2000-60 (2000-07).

  As described above, the pilot signal used for calculating the reference amplitude necessary for phase compensation and demapping of the received signal is subjected to transmission power control on the transmission side so that the reception power of all subcarriers is constant. . However, as shown in FIG. 17A, when there is a subcarrier (for example, part 260) whose propagation path condition is extremely bad, if the transmission power is controlled so that such subcarrier also satisfies a certain reception power, However, very large transmission power is required, which may exceed the range of transmission power allowed by the system (FIG. 17: part 261). Normally, a signal having power exceeding the maximum transmission power of the system cannot be transmitted, so transmission is performed with the maximum transmission power within the allowable range. In such a case, the reception power of the corresponding subcarrier is other than It becomes lower than the received power of the subcarrier (FIG. 17: part 262). In this case, there is a problem that an error occurs in the reference amplitude calculated using the corresponding subcarrier, and the accuracy of demapping deteriorates.

  In view of the above problems, an object of the present invention is to provide a technique for improving the calculation accuracy of a reference amplitude used for demapping in a multicarrier transmission system using a subcarrier adaptive modulation scheme.

  In the present invention, two pilot signals for propagation path estimation are prepared in a frame, for example, and the demapping of the modulation information signal is performed using the phase fluctuation value estimated by the first pilot signal and the demapping reference amplitude. I do. Further, for the data signal, the phase variation value estimated from the second pilot signal to which transmission power control similar to that for the data signal is applied for each subcarrier and the demapping reference amplitude are used. As described above, the propagation path compensation using the pilot signal subjected to the same transmission power control as that of the data signal takes into account the amplitude ratio due to the difference in the modulation multi-level number of the pilot signal and the data signal to which different transmission power control is applied. Compared with the conventional reference amplitude calculation method, the calculation accuracy of the reference amplitude is improved, so that data can be demodulated more correctly. In this way, a technique for improving the reference amplitude calculation accuracy in data signal demapping is realized by adopting a frame configuration in which two pilot signals of different targets to which the propagation path estimation value is applied are provided.

  According to the present invention, in a multicarrier transmission system using a subcarrier adaptive modulation scheme, when different transmission power control is applied to a modulation information signal and a data signal, the calculation accuracy of a reference amplitude in demapping is improved. There is an advantage that you can.

  First, FIG. 11 shows an application mode of the wireless communication technology according to the present invention. As shown in FIG. 11, the present invention can be applied to a wireless communication system 132 that includes a transmission device 130 and a reception device 131 each having an antenna ANT.

  Hereinafter, a wireless communication technique according to an embodiment of the present invention will be described in detail. First, an outline of a frame configuration and a received power spectrum according to this embodiment is shown in FIGS. 1 and 2, respectively.

  As shown in FIG. 1, in the radio communication technique according to an embodiment of the present invention, first, a phase fluctuation value estimated from a first pilot signal 1 provided at the head of a frame, a reference amplitude in demapping, Thus, propagation path compensation of the modulation information signal 3 is performed. Subsequently, propagation path compensation of the data signal 4 is performed based on the modulation information decoded thereafter, the phase fluctuation value estimated from the second pilot signal 2, and the reference amplitude in demapping. Here, the number of modulation multilevels in the first pilot signal 1 and the second pilot signal 2 is the same, but the first pilot signal 1 includes all subcarriers on the receiving side as in the modulation information signal 3. The transmission power control is performed to keep the reception power constant (FIG. 2: spectrum 5), and the second pilot signal 2 is configured to perform the same transmission power control as the data signal (FIG. 2: spectrum 6). Therefore, in the subcarrier adaptive modulation system, there is a case where the transmission efficiency is prevented from being lowered by assigning a carrier hole to a subcarrier having a remarkably low reception power, but the subcarrier which is a carrier hole in the data signal is prevented. The carrier also becomes a carrier hole in the second pilot signal (FIG. 2: subcarrier 7).

Next, FIG. 3 shows a transceiver configuration corresponding to such a frame. First, a configuration example of a transmitter according to this embodiment will be described.
In the transmitter 33 shown in FIG. 3, first, the modulation scheme / transmission power determination unit 23 determines the modulation level and transmission power used in the data signal in consideration of the propagation path conditions of the subcarriers. Here, the transmission power given to each subcarrier of the second pilot signal is set equal to the transmission power of the corresponding subcarrier in the data signal. At the same time, the transmission power of the first pilot signal and the modulation information signal is determined in consideration of the propagation path condition for each subcarrier so that the reception power of each subcarrier is constant. At this time, a modulation information signal representing modulation multi-level information used in each subcarrier of the data signal is also generated.

  Next, in the modulation unit 24, transmission data is modulated by the previously determined modulation multilevel number, and a data signal is generated. Further, the pilot signal generation unit 25 generates first and second pilot signals. Next, the power control unit 26 controls transmission powers of the first and second pilot signals, the modulation information signal, and the data signal, respectively. Here, as described above, the power of the first pilot signal and the modulation information signal is controlled so that the reception power of each subcarrier is constant (see FIG. 2: spectrum 5). The data signal is subjected to power control so that the modulation multi-level number of each subcarrier satisfies the required BER, and the second pilot signal is subjected to transmission power control similar to that of the data signal (FIG. 2: spectrum). 6). Next, each signal is collected into a frame as shown in FIG. 1 and FIG. 2, and after being converted into a time domain signal by the serial / parallel conversion 28 and IFFT circuit 29, the signal is transmitted from the antenna ANT via the RF circuit 31 and the like. Is done.

  Next, the operation of the receiver of this embodiment will be described (FIG. 3: 32). In the receiver 32 shown in FIG. 3, the signal received by the antenna ANT is input to the receiver 32 via the RF circuit 31 and the like, and is passed through the FFT circuit 10 and the parallel-serial converter (P / S) 11. After passing, the signal separation unit 12 separates the first pilot signal, the modulation information signal, the second pilot signal, and the data signal.

  Next, the first pilot signal and the second pilot signal are respectively input to the first and second phase fluctuation estimators 13 and 14, and the respective phases are determined from the received first pilot signal and second pilot signal. The amount of variation is estimated. Here, the estimated phase fluctuation amount is input to the phase fluctuation compensation units 15 and 16, respectively. In the phase fluctuation compensation unit 15, the first pilot signal and the modulation information signal are input. In the phase fluctuation compensation unit 16, the second pilot signal is input. The phase variation of the data signal is compensated for each subcarrier.

  Next, the first pilot signal after phase fluctuation compensation is input to the reference amplitude calculation unit 17, and the reference amplitude necessary for demapping the modulation information signal is received using the reception amplitude of the first pilot signal. Calculation is performed for each subcarrier. Similarly, the second pilot signal after phase fluctuation compensation is input to the reference amplitude calculation unit 18, and the reference amplitude necessary for demapping the data signal is calculated for each subcarrier. Next, the reference amplitude calculated from the reception amplitude of the first pilot signal and the phase-modulated modulation information signal are simultaneously input to the demapping unit 20, and the reception amplitude of the reference amplitude and the modulation information signal are subcarriers. After performing the demapping by comparing each time, the Viterbi decoder 21 decodes the signal, and the modulation multilevel number information used in each subcarrier is obtained. Further, the reference amplitude calculated from the reception amplitude of the second pilot signal, the data signal after phase compensation and the decoded subcarrier modulation multilevel number information are simultaneously input to the demapping unit 20, and the reference amplitude And demapping is performed by comparing the received amplitude of the data signal for each subcarrier, and then the Viterbi decoder 21 decodes the data.

  As described above, by applying the same transmission power control to the second pilot signal as the data signal, the received power in the same subcarrier corresponding to the second pilot signal and the data signal becomes equal, and the second pilot signal becomes equal. Since the received amplitude of the signal can be used as it is as the reference amplitude in demapping, the calculation accuracy of the reference amplitude is improved. Furthermore, when calculating the reference amplitude in demapping, it is not necessary to correct the amplitude ratio due to the difference in the number of modulation levels used, so the conventional amplitude ratio calculation unit 236 and reference amplitude correction unit 237 shown in FIG. 16 are omitted. There is an advantage that you can.

  In the configuration according to the above embodiment (FIG. 3), the phase fluctuation estimation units 13 and 14, the phase compensation units 15 and 16, and the reference amplitude calculation units 17 and 18 are for the first pilot signal and the second pilot. Although the example is divided into those for signals, the phase compensation of the first pilot signal and the second pilot signal and the calculation of the reference amplitude are performed in a time division manner so that these blocks are shared. be able to. FIG. 4 shows a configuration example of a transmitter / receiver when shared.

  As shown in FIG. 4, the receiver 53 temporally switches the input to the phase fluctuation estimation unit 45, the phase fluctuation compensation unit 46, etc. with two SWs (switches) 43 and 44, and the phase estimation unit shown in FIG. By using the blocks 13 and 14, the phase compensation units 15 and 16, and the reference amplitude calculation units 17 and 18 in common for the first pilot signal and the second pilot signal, the configuration of the receiver is greatly increased. It can be simplified.

  Further, in FIG. 1, the second pilot signal 2 is subjected to the same transmission power control as that of the data signal 4, but separately from this, the received power of the subcarrier in the second pilot signal 2 is the required BER. It is also possible to adopt a configuration in which transmission power control is performed so that a constant value that satisfies the above is satisfied. The frame configuration and received power spectrum in this case are shown in FIGS. 5 and 6, respectively. However, even in the case of the configuration shown in FIG. 5, for the subcarrier (FIG. 6: subcarrier 67) that becomes a carrier hole in the data signal 4, the carrier hole (FIG. 6: subcarrier also in the second pilot signal 2). 65). In such a case, SNR can be improved by distributing the power of subcarriers serving as carrier holes to other subcarriers (giving a margin) (FIG. 6: part 66). In particular, by providing a power margin to a subcarrier to which a modulation multi-level number that is high rate but is vulnerable to noise, such as 64QAM, is assigned, it is possible to increase noise resistance.

  As described above, in the frame configurations shown in FIGS. 1 and 5, propagation path compensation of the data signal is performed based on the phase fluctuation value and the reference amplitude estimated from the second pilot signal. The estimated value of fluctuation may be a value obtained from the first pilot signal, and the value obtained from the second pilot signal may be used as the reference amplitude in demapping. Such a frame configuration and a transceiver configuration will be described with reference to FIGS.

  As shown in FIG. 7, the phase fluctuation of the modulation information signal 72, the reference amplitude, and the phase fluctuation of the data signal 73 use the channel estimation value estimated from the first pilot signal 70 (FIG. 8: block 83, block 85) For the reference amplitude used for demapping of the data signal 73, a value calculated from the second pilot signal 71 subjected to the same transmission power control as that of the data signal 73 is used. At this time, the second pilot signal 71 may be configured to perform transmission power control in which the reception power of subcarriers other than the carrier holes is constant as in the case of FIG.

  Further, the first pilot signal and the second pilot signal before phase fluctuation compensation may be combined and the combined signal may be used to estimate the phase fluctuation of the modulation information signal and the data signal. The frame configuration and transceiver configuration in this case will be described with reference to FIGS. 9 and 10, respectively.

  As shown in FIG. 10, a combined signal obtained by combining the first pilot signal and the second pilot signal for each subcarrier in the vector combining unit 113 is input to the phase variation estimating unit 114, and the phase variation amount is estimated. . Also in this configuration, the demapping reference amplitude of the modulation information signal is calculated from the first pilot signal, and the demapping reference amplitude of the data signal is calculated from the second pilot signal. Thus, by adopting the configuration shown in FIG. 9 in which the phase fluctuation amount is estimated from the combined signal of the two pilot signals, the tolerance to noise can be improved.

  Further, unlike the configuration shown in FIG. 9, the phase fluctuation amounts are estimated separately from the first pilot signal and the second pilot signal, and the averages of these are obtained as the phase of the modulation information signal and the data signal. Even in the configuration used for fluctuation compensation, it is possible to improve resistance to noise as in the configuration shown in FIG.

  In the above frame configuration, the first pilot signal that plays the role of propagation path estimation is provided at the beginning of the frame, but normally, before the pilot signal for propagation path estimation, signal detection and AGC (Automatic Gain) Control), a preamble that plays a role such as synchronization processing is often added. Further, in the frame shown in FIG. 1 and the like, the control signal is only the modulation information signal, but in addition to this, several control signals and dummy data that plays the role of guard time are inserted in the frame. It is also conceivable. Therefore, the insertion positions of the first and second pilot signals are not fixed so that they can be flexibly dealt with even in such a case, and the first pilot signals are propagated in the modulated information signal depending on the system. It is desirable to set the second pilot signal at a position where the path compensation of the data signal can be easily performed at a position where the path compensation can be easily performed.

  Further, in the above configuration, the modulation multi-level number used in the first pilot signal and the second pilot signal is common, but separately, different modulation is used in the first pilot signal and the second pilot signal. It is good also as a structure using a multi-value number.

  In general, the modulation multilevel number used in the pilot signal is a low rate modulation multilevel number (BPSK, QPSK), so that the required transmission power is lower than that of a data signal using a high rate modulation multilevel number. It may be low. However, since the transmittable power is the same in the pilot signal and the data signal, a large surplus power is generated in the pilot signal. Depending on the system, the surplus power can be added to the pilot signal to improve the SNR of the pilot signal. In some cases, For such a system, when calculating the reference amplitude value used for demapping, the surplus power was taken into account, such as calculating the reference amplitude after subtracting the added surplus power from the received power. By performing the control, it is possible to respond flexibly.

  The subcarrier adaptive modulation scheme to which the present invention is applied is a scheme for controlling the modulation multi-level number, coding rate, and transmission power for each subcarrier according to the condition of the propagation path. In addition, not only the received power of the subcarrier but also a parameter indicating the channel condition such as SNR and SINR may be used as an indicator of the channel condition.

  The technology of the present invention can be applied to a general wireless communication system. For example, the technology of the present invention can be applied to a wireless communication technology using a mobile terminal in addition to a wireless communication system using a personal computer.

It is a figure which shows the structural example of the 1st flame | frame which can be applied to the radio | wireless communication technique by one embodiment of this invention. It is a figure which shows the structural example of the 1st received spectrum which can be applied to the radio | wireless communication technique by one embodiment of this invention (corresponding to FIG. 1). It is a figure which shows the structure of the transmitter / receiver which can be applied to the radio | wireless communication technique by one embodiment of this invention (corresponding to FIG. 1). It is a figure which shows the transmitter-receiver structure which can be applied to the radio | wireless communication technique by one embodiment of this invention. It is a figure which shows the 2nd frame structural example applicable to the radio | wireless communication technique by one embodiment of this invention. FIG. 6 is a diagram showing a second received spectrum example (corresponding to FIG. 5) that can be applied to the wireless communication technique according to the embodiment of the present invention. It is a figure which shows the 3rd frame structural example applicable to the radio | wireless communication technique by one embodiment of this invention. It is a figure which shows the 3rd structural example of the transmitter / receiver which can be applied to the radio | wireless communication technique by one embodiment of this invention (corresponding to FIG. 7). It is a figure which shows the example of a 4th frame structure applicable to the radio | wireless communication technique by one embodiment of this invention. It is a figure which shows the 4th structural example (corresponding to FIG. 8) of the transmitter / receiver applicable to the radio | wireless communication technique by one embodiment of this invention. It is a figure which shows the basic structural example of the radio | wireless communications system of this invention. It is a figure which shows the transmission / reception spectrum of a single carrier and a multicarrier. It is a figure which shows the outline | summary of multilevel transmission power control. It is a figure which shows the example of a frame structure in a prior art example. It is a figure which shows the reception spectrum in a prior art example. It is a figure which shows the conventional transmitter-receiver structure. It is a figure which shows the problem of a prior art.

Explanation of symbols

1, 60, 70, 100 First pilot signal
2, 61, 71, 101 Second pilot signal
3, 62, 72, 102, 221 Modulation information signal
4, 63, 73, 103, 222 Data signal
5, 6, 64, 67, 223, 224 reception spectrum
7, 65, 212, 213 Career Hall
10, 40, 80, 110, 230 FFT circuit
11, 41, 81, 111, 231 Parallel to serial converter
12, 42, 82, 112, 232 Signal separator
13, 14, 45, 83, 114, 233 Phase fluctuation estimator
15, 16, 46, 85, 116, 234 Phase fluctuation compensator
17, 18, 47, 86, 117, 235 Reference amplitude calculator
19, 30, 43, 44, 51, 84, 90, 115, 121, 238, 249 switch
20, 48, 87, 118, 239 Demapping part
21, 49, 88, 119, 240 Viterbi decoder
22, 50, 89, 120, 241 MAC layer
23, 242 Modulation method / Transmission power determination unit
24, 243 Modulator
25, 244 Pilot signal generator
26, 245 Power control unit
27, 246 Multiplexer
28, 247 series-parallel converter
29, 248 IFFT circuit
31, 52, 91, 122, 250 RF circuits
32, 251 receiver
33,252 Transmitter
66 Power margin
113 Vector composition part
130 Transmitter
131 Receiver
132 Wireless communication system
200 Single carrier transmit spectrum
201 Single carrier reception spectrum
202, 210 Multicarrier transmission spectrum
203, 211 Multicarrier reception spectrum
220 Pilot signal
236 Amplitude ratio calculator
237 Reference amplitude correction unit
260 Frequency band with poor reception
261 Power exceeding the maximum transmission power
262 Subcarriers with reduced received power

Claims (14)

A transmission apparatus in a multicarrier communication system, wherein a modulation scheme selecting unit for each subcarrier that selects a modulation scheme of each subcarrier according to a propagation characteristic of a propagation path, and each subcarrier according to a propagation characteristic of a propagation path Transmission power adjusting means for each subcarrier for individually adjusting the transmission power of
A signal transmission basic unit generating means for generating a signal sequence having a pilot signal for transmission path characteristic confirmation, a control signal, and a data signal as a basic unit of signal transmission;
First pilot signal generating means for generating a first pilot signal for the control signal;
A transmission apparatus comprising: a second pilot signal generation unit configured to generate a second pilot signal for the data signal. Transmission by subcarrier that adjusts the transmission power of each subcarrier in a direction in which the size of all carriers of the multicarrier signal received on the receiving side is substantially constant during the transmission period of the first pilot signal and the control signal. The transmission apparatus according to claim 1, further comprising a power adjustment unit. The transmission power adjusting means for each subcarrier further performs control to adjust the transmission power of each subcarrier in the transmission period of the second pilot signal and the transmission period of the data signal so as to be substantially the same. The transmission device according to claim 2 . A signal format having a signal sequence including a pilot signal region for confirming transmission path characteristics, a control signal region, and a data signal region as a basic unit of signal transmission, wherein the pilot signal region is used for the control signal region A receiving apparatus in a multi-carrier communication system for receiving a signal of a signal format characterized by having a first pilot signal region and a second pilot signal region for the data signal region,
Based on the received first pilot signal, a phase fluctuation amount with respect to the control signal is estimated, and a phase fluctuation amount between the first pilot signal and the control signal is compensated for each subcarrier of the control signal. First compensation means for
First reference amplitude calculation means for calculating a first reference amplitude for each subcarrier of the control signal based on a reception amplitude of each subcarrier of the first pilot signal;
First demapping means for performing demapping by comparing the reception amplitude of the control signal compensated for the phase fluctuation and the first reference amplitude with respect to each subcarrier;
A receiving apparatus comprising: first modulation information acquisition means for performing decoding based on a demapping result of the control signal and acquiring modulation information for each subcarrier of the data signal. Further, based on the received second pilot signal, a phase fluctuation amount with respect to the data signal is estimated, and a phase fluctuation amount between the second pilot signal and the data signal is calculated for each subcarrier of the data signal. Second compensation means for compensating
Second reference amplitude calculation means for calculating a second reference amplitude for each subcarrier of the data signal based on the reception amplitude of each subcarrier of the second pilot signal;
Based on the decoded modulation information, a second demapping is performed in which the received amplitude of the data signal in which the phase variation is compensated and the second reference amplitude are compared with each subcarrier for demapping. Means,
First demodulation means for performing decoding and demodulating the data signal based on a demapping result of the data signal;
The receiving apparatus according to claim 4 , further comprising: Based on the received first pilot signal, a phase fluctuation amount with respect to the data signal is estimated, and a phase fluctuation amount between the first pilot signal and the data signal is compensated for each subcarrier of the data signal. Third compensation means for
Third reference amplitude calculation means for calculating a second reference amplitude for each subcarrier of the data signal based on the reception amplitude of each subcarrier of the second pilot signal;
Based on the decoded modulation information, the received amplitude of the data signal compensated for the phase variation and the second reference amplitude are compared with respect to each subcarrier, and demapping is performed. Demapping means,
The receiving apparatus according to claim 4 , further comprising: a second demodulating unit that performs decoding based on a demapping result of the data signal and demodulates the data signal. A signal format having a signal sequence including a pilot signal region for confirming transmission path characteristics, a control signal region, and a data signal region as a basic unit of signal transmission, wherein the pilot signal region is used for the control signal region A receiving apparatus in a multi-carrier communication system for receiving a signal of a signal format characterized by having a first pilot signal region and a second pilot signal region for the data signal region,
Based on a synthesized signal obtained by synthesizing received signal points of the received first pilot signal and the received second pilot signal, a phase fluctuation amount with respect to the control signal is estimated, and the synthesized signal and the control Fourth compensation means for compensating for the amount of phase variation with respect to each subcarrier of the control signal;
Fourth reference amplitude calculating means for calculating a first reference amplitude for each subcarrier of the control signal based on a reception amplitude of each subcarrier of the first pilot signal;
A fourth demapping means for performing demapping by comparing the reception amplitude of the control signal compensated for the phase fluctuation and the first reference amplitude with respect to each subcarrier;
And a second modulation information acquisition unit configured to perform decoding based on a demapping result of the control signal and acquire modulation information for each subcarrier of the data signal. A fifth compensation unit that estimates a phase fluctuation amount with respect to the data signal based on the synthesized signal and compensates a phase fluctuation amount between the synthesized signal and the data signal for each subcarrier of the data signal;
Fifth reference amplitude calculation means for calculating a second reference amplitude for each subcarrier of the data signal based on the reception amplitude of each subcarrier of the second pilot signal;
Based on the decoded modulation information, the received amplitude of the data signal compensated for the phase variation and the second reference amplitude are compared for each subcarrier, and demapping is performed. Demapping means,
The receiving apparatus according to claim 7 , further comprising: a third demodulating unit that performs decoding based on a demapping result of the data signal and demodulates the data signal. Further, in the control signal and the data signal, the calculation of the compensation and the reference amplitude of the phase deviation, claim 4, which comprises carrying out the time division by using a common processing system to 8 The receiving device according to Item 1. At least one transmission device according to any one of claims 1 to 3 , and
A wireless communication system comprising: at least one receiving device according to any one of claims 4 to 8 . At least one transmission device according to any one of claims 1 to 3 , and
A wireless communication terminal comprising at least one of the at least one receiving device according to any one of claims 4 to 8 . A transmission apparatus in a multicarrier communication system, wherein a modulation scheme selecting unit for each subcarrier that selects a modulation scheme of each subcarrier according to a propagation characteristic of a propagation path, and each subcarrier according to a propagation characteristic of a propagation path A transmission method using a transmission device comprising subcarrier-specific transmission power adjustment means for individually adjusting the transmission power of
Generating a signal sequence having a pilot signal for confirming transmission path characteristics, a control signal, and a data signal as a basic unit of signal transmission;
A first pilot signal generating step for generating a first pilot signal for the control signal;
And a second pilot signal generation step of generating a second pilot signal for the data signal. A signal format having a signal sequence including a pilot signal region for confirming transmission path characteristics, a control signal region, and a data signal region as a basic unit of signal transmission, wherein the pilot signal region is used for the control signal region A reception method in a multi-carrier communication system for receiving a signal of a signal format characterized by having a first pilot signal region and a second pilot signal region for the data signal region,
Based on the received first pilot signal, the amount of phase fluctuation with respect to the control signal is estimated, and the amount of phase fluctuation between the younger pilot signal and the control signal is compensated for each subcarrier of the control signal. A first compensation step,
A first reference amplitude calculating step of calculating a first reference amplitude for each subcarrier of the control signal based on a reception amplitude of each subcarrier of the first pilot signal;
A first demapping step of performing demapping by comparing the reception amplitude of the control signal compensated for the phase variation and the first reference amplitude with respect to each subcarrier;
A reception method comprising: a first modulation information acquisition step that performs decoding based on a demapping result of the control signal and acquires modulation information for each subcarrier of the data signal. Program for executing the method according to the computer to claim 1 2 or 1 3.

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