JP4820874B2 - Transmitting apparatus, receiving apparatus, and multicarrier transmission / reception system - Google Patents

Description

  The present invention relates to a transmission apparatus, a reception apparatus, and a multicarrier transmission / reception system, and more particularly, to a transmission apparatus, a reception apparatus, and a multicarrier transmission / reception system using an OFDM (Orthogonal Frequency Division Multiple Access) scheme.

  In a wireless communication system, a multicarrier modulation / demodulation scheme having advantages such as resistance to multipath interference has attracted attention. Among them, the range of use of the OFDM system with high frequency utilization efficiency is expanding. In the OFDM scheme, data is interleaved in the frequency direction in order to disperse characteristic degradation due to frequency such as frequency selective fading. Further, when the error rate is high, a stronger error correction code is used. Further, in the multi-level modulation scheme, an adaptive modulation scheme that switches to a modulation scheme with high error tolerance such as BPSK (Binary Phase Shift Keying) may be used.

  The following method is known as a wireless communication method in which a wireless transmission device transmits a multicarrier signal composed of a plurality of subcarriers to a wireless reception device. In this wireless communication method, the wireless transmission device increases the number of bits that can be included in the multicarrier signal by increasing the modulation multi-value number, and each of the plurality of identical bits is transmitted to each of the subcarriers having different frequencies. To generate a multicarrier signal including a plurality of the same bits having different frequencies, and the wireless reception device combines the likelihoods of the plurality of the same bits copied by the wireless transmission device (for example, Patent Document 1). reference.).

JP 2003-258757 A (Claim 1)

  However, in the conventional method for the characteristic deterioration due to the above-described frequency, even if the characteristics of some subcarriers are deteriorated, it affects the increase in the error rate of the entire transmission line, and a stronger error correction code is used. In addition, there is a problem that the transmission efficiency is lowered because the modulation method is switched to a higher error tolerance. In addition, the method disclosed in Patent Document 1 has a problem that the efficiency of the entire transmission line is low from the beginning because a plurality of subcarriers are set and the same data is transmitted in duplicate.

  In order to solve the above-described problems caused by the prior art, the present invention provides a transmitter, receiver, and multicarrier capable of obtaining high error rate tolerance without substantially reducing transmission efficiency in a radio communication system using a multicarrier modulation / demodulation method. An object is to provide a transmission / reception system.

  In order to solve the above-described problems and achieve the object, a transmission apparatus, a reception apparatus, and a multicarrier transmission / reception system according to the present invention have the following characteristics. The receiving side detects a subcarrier with a high error rate for each subcarrier, that is, a subcarrier with low communication quality, and notifies the transmitting side of the detection result. On the transmission side, the notification is received, and based on the detection result of the subcarriers with low communication quality, a plurality of subcarriers with low communication quality are collectively assigned to the transmission channel of the same data, and are assigned to the plurality of subcarriers of the transmission channel. The same data is multiplexed and assigned. On the receiving side, the demodulated data of information transmitted by a plurality of subcarriers assigned to the same data transmission channel is combined. The same applies to the case where the same data is multiplexed and assigned in units of subchannels in which a plurality of subcarriers are combined.

  According to the present invention, for subcarriers with high communication quality, one data is transmitted on one subcarrier as usual. For subcarriers with low communication quality, the same data is transmitted on a plurality of subcarriers, and the same data on a plurality of subcarriers is synthesized on the receiving side to obtain one original data.

  According to the transmission device, the reception device, and the multicarrier transmission / reception system according to the present invention, there is an effect that high error rate tolerance can be obtained without substantially reducing the transmission efficiency.

  Exemplary embodiments of a transmission device, a reception device, and a multicarrier transmission / reception system according to the present invention will be explained below in detail with reference to the accompanying drawings. Although not particularly limited, when the multicarrier transmission / reception system according to the present invention is applied to a mobile phone system, the transmission device and the reception device are a base station and a mobile terminal, respectively. When the multicarrier transmission / reception system according to the present invention is applied to a terrestrial digital broadcasting system, the transmitting device and the receiving device are televisions compatible with broadcasting stations and digital TV tuner broadcasting, respectively.

(Configuration of transmitter)
First, the configuration of the transmission apparatus according to the embodiment of the present invention will be described. FIG. 1 is a block diagram showing a configuration of a transmission apparatus according to an embodiment of the present invention. As shown in FIG. 1, a transmission apparatus 1 includes a multiplexed data generation unit 11, a modulation / encoding unit 12, an inverse fast Fourier transform unit (hereinafter referred to as IFFT unit) 13, a transmission RF unit 14, an antenna switch (in the figure). 15, an antenna 16, a reception RF unit 17, a fast Fourier transform unit (hereinafter referred to as FFT unit) 18, a demodulation / decoding unit 19, and a control unit 20.

  The multiplexed data generation unit 11 multiplexes the data allocated to the plurality of subcarriers in the transmission data so that the same data can be allocated to the plurality of subcarriers determined by the control unit 20. The multiplexed data generation unit 11 has a function as multiplexing means. Immediately after the operation is started, the multiplexed data generation unit 11 outputs the transmission data as it is without multiplexing the data. Further, the multiplexed data generation unit 11 outputs data that does not need to be multiplexed out of the transmission data as it is.

  The modulation / encoding unit 12 generates modulation data from the bit sequence of the transmission data output from the multiplexed data generation unit 11 for each subcarrier. Usually, one of a plurality of multi-level modulations such as BPSK, QPSK (Quadrature Phase Shift Keying) or 16QAM (16 Quadrature Amplitude Modulation) is selected for modulation, and transmission symbol sequence data is configured based on the selected one. .

  The IFFT unit 13 performs an inverse fast Fourier transform process on the symbol data output from the modulation / encoding unit 12 to generate a multicarrier modulation signal composed of a plurality of subcarriers having different frequencies. The transmission RF unit 14 performs predetermined radio processing on the multicarrier modulation signal output from the IFFT unit 13 and transmits the result to a reception device (not shown) via the antenna switch 15 and the antenna 16.

  The reception RF unit 17 performs radio processing such as down-conversion and analog / digital conversion on the received signal received from the receiving device (not shown) via the antenna 16 and the antenna switch 15. The FFT unit 18 performs a fast Fourier transform process on the multicarrier modulation signal output from the reception RF unit 17 and divides it into symbol information for each subcarrier. The demodulation / decoding unit 19 demodulates the data divided for each subcarrier by the FFT unit 18 in reverse to the modulation by a receiving device (not shown) to obtain received data.

  This received data includes information on subcarriers with low communication quality. The control unit 20 determines a plurality of subcarriers to be allocated to the transmission channel of the same data from a plurality of subcarriers with low communication quality based on information on subcarriers with low communication quality. Therefore, the multiplexed data generation unit 11 multiplexes the data by the control unit 20 by the number of subcarriers assigned to the transmission channel of the same data.

(Receiver configuration)
Next, the configuration of the receiving apparatus according to the embodiment of the present invention will be described. FIG. 2 is a block diagram showing the configuration of the receiving apparatus according to the embodiment of the present invention. As shown in FIG. 2, the receiving device 3 includes an antenna 31, an antenna switch (denoted as “SW” in the figure) 32, a reception RF unit 33, an FFT unit 34, a demodulation / decoding unit 35, a quality detection unit 36, a multiplexing unit. A data synthesis unit 37, a control unit 38, a modulation / encoding unit 39, an IFFT unit 40, and a transmission RF unit 41 are provided.

  The reception RF unit 33 performs radio processing such as down-conversion and analog / digital conversion on the received signal received from the transmission device (not shown) via the antenna 31 and the antenna switch 32. The FFT unit 34 performs a fast Fourier transform process on the multicarrier modulation signal output from the reception RF unit 33 and divides it into symbol information for each subcarrier. The quality detection unit 36 detects communication quality, such as an error rate, for each subcarrier. The quality detection unit 36 has a function as detection means.

  The multiplexed data combining unit 37 includes data of a plurality of subcarriers to which the same data is allocated among the data divided for each subcarrier by the FFT unit 34, that is, data multiplexed in a transmission device (not shown) ( (Hereinafter referred to as multiplexed channel data) is separated for each subcarrier, and the data separated for each subcarrier is combined. Which subcarrier is assigned the same data is included in a received signal received from a transmitting apparatus (not shown). The multiplexed data synthesis unit 37 has a function as a synthesis unit.

  The demodulator / decoder 35 includes subcarrier data (hereinafter referred to as normal channel data) to which the same data is not allocated among the data divided by the FFT unit 34 for each subcarrier, and a multiplexed data synthesizer. Both of the combined data output from 37 are subjected to demodulation reverse to the modulation by a transmission device (not shown) to obtain received data.

  Based on the communication quality of each subcarrier detected by the quality detection unit 36, the control unit 38 generates notification information for a transmission device (not shown). This notification information includes information on subcarriers with low communication quality. The modulation / encoding unit 39 generates modulation data by superimposing the data of the notification information generated by the control unit 38 on the bit sequence of transmission data for each subcarrier.

  The IFFT unit 40 performs an inverse fast Fourier transform process on the symbol data output from the modulation / encoding unit 39 to generate a multicarrier modulation signal composed of a plurality of subcarriers having different frequencies. The transmission RF unit 41 performs predetermined radio processing on the multicarrier modulation signal output from the IFFT unit 40, and transmits the result to a transmission device (not shown) via the antenna switch 32 and the antenna 31. Therefore, the control unit 38, the modulation / encoding unit 39, the IFFT unit 40, the transmission RF unit 41, the antenna switch 32, and the antenna 31 have a function as notification means for notifying the transmission side of information on the communication quality of the subcarrier.

(Concept of data allocation to multiple subcarriers)
Next, the concept of data allocation to a plurality of subcarriers will be described. FIG. 3 is an explanatory diagram showing an example when data is allocated to each subcarrier of the OFDM scheme by the multicarrier transmission / reception system according to the embodiment of the present invention. In the OFDM system, data communication is performed using a plurality of subcarriers. However, due to the influence of the transmission path, the reception level of a specific subcarrier may be lowered and the communication quality may be frequently lowered when viewed on the frequency axis.

  In the example shown in FIG. 3, the communication quality is degraded for subcarriers with subcarrier numbers 2, 8, and 11. In addition, communication quality may deteriorate due to noise or interference waves mixed in a specific subcarrier. In such a case, in the embodiment, as shown in FIG. 3, for example, data C is multiplexed on subcarriers of subcarrier numbers 2, 8, and 11 with low communication quality, and the same data C is transmitted on these three subcarriers. Send.

(Overall operation)
Next, the overall operation will be described. FIG. 4 is a flowchart showing the overall operation of the multicarrier transmission / reception system according to the embodiment of the present invention. As shown in FIG. 4, first, immediately after the operation starts, the transmission apparatus 1 transmits an OFDM-modulated signal addressed to the reception apparatus 3 (step S1). The receiving device 3 receives the signal transmitted from the transmitting device 1 and measures the communication quality for each subcarrier (step S2). Next, the reception device 3 generates subcarrier information with low communication quality (hereinafter referred to as low quality subcarrier information) and notifies the transmission device 1 of the information (step S3).

  The transmission device 1 receives the low quality subcarrier information from the reception device 3, and determines a plurality of subcarriers to which the same data is allocated, that is, a subcarrier to be multiplexed, from among a plurality of subcarriers with low communication quality (step S4). Then, the transmission apparatus 1 generates multiplexed data for multiplexed subcarriers. That is, the transmission apparatus 1 multiplexes data to be allocated to a plurality of subcarriers with low communication quality (step S5). Next, the transmission device 1 transmits the unmultiplexed data and the multiplexed data to the reception device 3 together (step S6).

  The receiving device 3 separates and combines the multiplexed subcarriers and demodulates them. That is, the receiving device 3 receives the signal transmitted from the transmitting device 1, and uses the received signal as a subcarrier group (referred to as a first group) to which the same data is assigned and a subcarrier group (not the same) ( Separated into a second group). Then, the receiving apparatus 3 combines the data separated into the first group of subcarriers, and demodulates them together with the second group of data (step S7).

  By doing so, the error rate of the data received by the receiving device 3 can be reduced, so that the communication quality can be improved without substantially reducing the overall transmission efficiency. Moreover, since this system is not subject to restrictions such as a modulation system, it can be used together with conventional communication quality improvement means such as an adaptive modulation system.

  FIG. 5 is a flowchart showing details of an operation of allocating data to subcarriers with low communication quality on the transmission device side. As illustrated in FIG. 5, the reception device 3 notifies the transmission device 1 of the low quality subcarrier information 5 (step S11). For example, the low-quality subcarrier information 5 includes a subcarrier number (low quality subcarrier number) 51 with low communication quality and information (quality level information) 52 indicating the quality level of the subcarrier of that number. It is included. The transmitter 1 receives the low quality subcarrier information 5 from the receiver 3 (step S12).

  In the transmission apparatus 1, the multiplexing number is determined from the quality level. That is, the transmission apparatus 1 determines the number of subcarriers to be multiplexed and the number of data to be transmitted on the subcarriers based on each quality level of the subcarrier group with low communication quality (step S13). Here, the number of subcarriers to be multiplexed is the number of subcarriers that transmit the same data. If a plurality of sets of subcarriers to be multiplexed can be formed, data can be transmitted by that number.

  For example, it is assumed that there are 12 subcarriers with low communication quality, and that it is determined from the overall communication quality that if five or more subcarriers with low communication quality are collected and the same data is transmitted, the data can be stably transmitted. In this case, if six subcarriers are set as a set of subcarriers to be multiplexed, two sets of subcarriers to be multiplexed can be formed, so that two data can be transmitted.

  Next, the transmitting apparatus 1 rearranges the subcarriers with low communication quality in descending order of quality level (step S14). For example, in the example shown in FIG. 3, the subcarriers with low communication quality are rearranged in the order of subcarrier numbers 8, 11, 2,. Next, the transmission apparatus 1 multiplexes data to be allocated to subcarriers to be multiplexed (step S15). Then, the transmission apparatus 1 assigns the multiplexed data to the rearranged subcarriers in descending order of the quality level. If there are a plurality of multiplexed data, the multiplexed data are alternately assigned to the rearranged subcarriers in descending order of quality level (step S16).

  For example, the data allocation example indicated by reference numeral 6 in FIG. 5 is a case where there are two data to be multiplexed, C and Z. In this case, data C is assigned to the subcarrier of subcarrier number 8 having the highest quality level, data Z is assigned to the subcarrier of subcarrier number 11 having the next highest quality level, and then the subcarrier having the next highest quality level. Data C is assigned to the subcarrier of number 2, and hereinafter, data Z, data C, and data Z are assigned in descending order of quality level.

  By assigning data in this way, the communication quality of data C and data Z can be almost the same in total. The same applies when the number of data to be multiplexed is three or more. In step S16, data that is not multiplexed is also assigned. In actual transmission, since the position of the subcarrier on the frequency axis does not change, data is inserted at a position of a predetermined frequency in accordance with the correspondence relationship between the subcarrier number and the data. Next, the transmission device 1 transmits data to the reception device 3 (step S17).

(Configuration of low quality subcarrier information)
FIG. 6 is an explanatory diagram showing an example of a configuration of low quality subcarrier information. In the example illustrated in FIG. 6, the quality information 72 is assigned after the ACK 71 in the response information (ACK signal) for notifying that the communication is normally performed from the receiving device to the transmitting device. The format of the quality information 72 includes, for example, an 8-bit low quality subcarrier number 73 and, for example, a 4-bit quality level information 74. In this example, the communication quality level is represented by 16 values at the maximum. In this case, the length of the ACK frame changes according to the number of subcarriers with low communication quality. The number of bits of the low quality subcarrier number 73 and the quality level information 74 may be other values.

  By the way, generally, the length of response information from the receiving device to the transmitting device is often determined within a certain range. Therefore, in the example shown in FIG. 6, when the number of subcarriers with low communication quality increases, the information amount of the quality information 72 increases, which may exceed the determined length of the response information. The reason why there are many subcarriers with low communication quality is that the channel quality is low, and there is a high possibility that an error will occur in response information from the receiving apparatus.

  Therefore, it is necessary to reduce the data amount of response information. Therefore, only the low quality subcarrier number 73 may be notified without notifying the quality level information. Or you may make it switch the information amount notified according to the number of subcarriers with low communication quality. For example, when there are few subcarriers with low communication quality, the low quality subcarrier number 73 and the quality level information 74 are sent as a set, and when the information amount of the quality information 72 is equal to or greater than a certain value, Only the carrier number 73 may be notified.

  Further, instead of sending only the quality level information of subcarriers with low communication quality, the quality level information of all subcarriers may be sent. In this case, the quality level information of each subcarrier is assigned to a fixed area. FIG. 7 is an explanatory diagram showing another example of the configuration of the low quality subcarrier information. FIG. 7 shows an example in which the quality level information of all subcarriers is assigned to a bit string having a fixed number of bits in the order of subcarrier numbers. In FIG. 7, the example of the allocation of the quality level information indicated by reference numeral 76 is an example in which the quality level information is 1 bit.

  In the quality level information allocation example 76, the level of communication quality is represented by a binary value of good / bad. The low quality subcarrier information requires the same number of bits as the number of subcarriers. In addition, in FIG. 7, an example of assignment of quality level information indicated by reference numeral 77 is an example in which the quality level information is 2 bits. In this case, the communication quality level is represented by four values at the maximum. As the low quality subcarrier information, the number of bits twice the number of subcarriers is required. The same applies when 3 bits or more are assigned to the quality level information.

(Transmission device operation)
Next, main operations of the transmission apparatus 1 will be described in detail. FIG. 8 is a flowchart showing main operations of the transmission apparatus according to the embodiment of the present invention. As illustrated in FIG. 8, the transmission device 1 receives the response information (ACK signal) sent from the reception device 3 and demodulates it by performing a fast Fourier transform in the same manner as the reception process using the normal OFDM method. And in the transmitter 1, the control part 20 extracts quality information, ie, the low quality subcarrier information 5, from the received data (step S21).

  Next, the control unit 20 determines the quality level of each subcarrier with low communication quality as described above based on the low quality subcarrier information 5 (step S22). And the control part 20 determines the number of multiplexing, ie, the number of the subcarriers multiplexed, based on the determination result (step S23). Next, the control unit 20 assigns a subcarrier number to be multiplexed based on the number of multiplexing (step S24).

  On the other hand, the multiplexed data generation unit 11 of the transmission device 1 separates the transmission data into data to be multiplexed and normal data that is not multiplexed based on the number of multiplexing determined in step S23 (step S25). Then, the multiplexed data generating unit 11 multiplexes the data to be multiplexed according to the number of subcarriers to be multiplexed (step S26), and performs deinterleaving only in the time axis direction (step S27). This deinterleaving only in the time axis direction will be described later.

  Subcarrier mapping is performed for normal data (step S28). At that time, interleaving is performed in both the frequency axis direction and the time axis direction. Next, the multiplexed data generation unit 11 combines the data interleaved in steps S27 and S28 (step S29), and sends it to the modulation / encoding unit 12. The processing after the modulation / encoding unit 12 is the same as the transmission processing by the normal OFDM method.

(Receiver operation)
Next, main operations of the receiving device 3 will be described in detail. FIG. 9 is a flowchart showing main operations of the receiving apparatus according to the embodiment of the present invention. As illustrated in FIG. 9, the reception device 3 receives the signal transmitted from the transmission device 1 and performs a fast Fourier transform in the same manner as the reception process using the normal OFDM method. In the receiving device 3, the demodulation / decoding unit 35 passes the multiplexed channel data out of the data received from the FFT unit 34 to the multiplexed data combining unit 37.

  The multiplexed data combining unit 37 performs multiplexed channel separation processing on the multiplexed channel data received from the demodulating / decoding unit 35, and separates each subcarrier (step S31). Then, the multiplexed data combining unit 37 combines the data separated into the subcarriers (step S32). The data combined by the multiplexed data combining unit 37 is returned to the demodulation / decoding unit 35. The demodulation / decoding unit 35 demodulates and decodes the data passed from the multiplexed data combining unit 37 and the normal channel data (step S33) to obtain received data.

  On the other hand, the quality detection unit 36 receives data of all channels from the FFT unit 34 and detects the communication quality of each subcarrier (step S34). And the control part 38 selects a subcarrier with low communication quality based on the quality detection result (step S35). Next, the control unit 38 compares the number of subcarriers with low communication quality with a preset threshold value (step S36).

  As a result, when the number of subcarriers with low communication quality is smaller than the threshold (step S36: Yes), notification information including a subcarrier number and quality information is generated. That is, low quality subcarrier information in which a low quality subcarrier number and quality level information are paired is generated, and notification information including this is generated (step S37). When the number of subcarriers with low communication quality is equal to or greater than the threshold (step S36: No), notification information including only the subcarrier number is generated. That is, low-quality subcarrier information having only a low-quality subcarrier number is generated, and notification information including this is generated (step S38). The notification information generated in step S37 or step S38 is sent to the modulation / encoding unit 39, subjected to modulation / encoding processing, subjected to inverse fast Fourier transform, and transmitted to the transmission apparatus 1.

(Arrangement of multiplexed data)
Next, the arrangement of multiplexed data will be described. In general, in wireless communication, data is interleaved to cope with burst noise and the like. Usually, in a multicarrier modulation scheme such as OFDM, deinterleaving is also performed in the frequency axis direction, that is, between subcarriers.

  However, in this embodiment, since the same data is transmitted on a plurality of subcarriers with low communication quality, interleaving in the time axis direction is not performed on the multiplexed data without interleaving in the frequency axis direction. Is called. Therefore, the multiplexed data generation unit 11 of the transmission apparatus 1 generates interleave patterns for the multiplexed data by the number of multiplexed data. An example of data mapping in that case is shown in FIG.

  Another example of data mapping is shown in FIG. The example shown in FIG. 11 performs dispersion in the time axis direction by shifting the start point of one frame of data for each subcarrier in a plurality of subcarriers transmitting the same data. FIG. 11 shows a case where the operation is performed in units of 16 symbols. Such a mapping example is effective when the same data is multiplexed.

  By the way, for data interleaving, it is necessary to perform data de-interleaving before data composition. Therefore, when the number of multiplexed data increases, there is a problem that the memory for deinterleaving increases. Therefore, when the number of multiplexed data is larger than a certain level, the same data arrangement may be used without performing interleaving as in the data mapping example shown in FIG. In this way, the circuit of the receiving device 3 can be reduced. In addition, in the receiving device 3, by performing the synthesis at the stage where each subcarrier is subjected to the fast Fourier transform processing, it is possible to increase the signal S / N ratio and demodulate the data with higher reliability. It becomes.

  As described above, according to the embodiment, for subcarriers with high communication quality, since one data is transmitted with one subcarrier as usual, a decrease in transmission efficiency can be prevented. On the other hand, for subcarriers with low communication quality, the same data is transmitted on a plurality of subcarriers and the same data on a plurality of subcarriers is combined on the receiving side to obtain the original data. The original data can be obtained even if the quality of the transmission path is deteriorated to such an extent that it cannot be demodulated only by the change or the modulation system change. Therefore, high error rate tolerance can be obtained without substantially reducing the transmission efficiency.

  As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made. Further, in the case of a multicarrier modulation / demodulation system that manages a plurality of subcarriers as one unit (subchannel), as shown in FIG. 13, a plurality of (four in the illustrated example) subcarriers are combined into one subcarrier. The same effect can be obtained by treating each subchannel in the same manner as the above-described subcarrier. In this case, in the above description, “subcarrier” may be read as “subchannel”. Note that the number of subcarriers constituting one subchannel may be two, three, or five or more. Furthermore, the present invention is applicable not only to the OFDM system but also to other multicarrier modulation / demodulation systems.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary Note 1) A transmission apparatus that transmits data by a multicarrier modulation / demodulation method including a plurality of subcarriers,
Control means for controlling the number of subcarriers assigned to the transmission channel of the same data according to the communication quality of the subcarriers;
And a multiplexing unit that multiplexes data allocated to a plurality of subcarriers allocated to the transmission channel of the same data by the control unit.

(Supplementary note 2) The transmission apparatus according to supplementary note 1, wherein the control means controls the number of subcarriers assigned to a transmission channel of the same data based on communication quality information notified from a reception side.

(Supplementary note 3) The transmission apparatus according to supplementary note 2, wherein the control means allocates a plurality of subcarriers having low communication quality to a transmission channel of the same data.

(Supplementary note 4) Any one of Supplementary notes 1 to 3, wherein the multiplexing means changes the order and arrangement of bit sequences of a plurality of subcarriers assigned to a transmission channel of the same data for each subcarrier. The transmission device according to one.

(Supplementary note 5) Any one of Supplementary notes 1 to 3, wherein the multiplexing means changes a bit sequence of a plurality of subcarriers assigned to a transmission channel of the same data for each subcarrier in the same order. The transmitting device according to any one of the above.

(Supplementary note 6) The transmission according to any one of Supplementary notes 1 to 3, wherein the multiplexing means makes the sequence of bit sequences of a plurality of subcarriers assigned to the transmission channel of the same data the same. apparatus.

(Supplementary note 7) A receiving device for receiving data transmitted by a multicarrier modulation / demodulation method including a plurality of subcarriers,
Detection means for detecting communication quality for each subcarrier;
Notification means for notifying the transmission side of information of communication quality detected by the quality detection means;
Combining means for combining information transmitted by a plurality of subcarriers assigned to the transmission channel of the same data;
A receiving apparatus comprising:

(Supplementary Note 8) The notification means sends information including only the position of the subcarrier with low communication quality and information including both the position of the subcarrier with low communication quality and the communication quality of the subcarrier to the transmission side. The receiving apparatus according to appendix 7, wherein the notification is switched according to the length of the message.

(Supplementary note 9) The receiving apparatus according to supplementary note 7, wherein the notification unit notifies a position of a subcarrier having low communication quality.

(Supplementary note 10) The receiving apparatus according to supplementary note 7, wherein the notification means notifies both of the position of a subcarrier having low communication quality and the communication quality of the subcarrier.

(Additional remark 11) The said notification means notifies the communication quality of all the subcarriers, The receiving apparatus of Additional remark 7 characterized by the above-mentioned.

(Supplementary note 12) A multicarrier transmission / reception system that transmits and receives data by a multicarrier modulation / demodulation method composed of a plurality of subcarriers,
Control means for controlling the number of subcarriers allocated to the transmission channel of the same data according to the communication quality of the subcarriers on the transmission side;
Multiplexing means for multiplexing data assigned to a plurality of subcarriers assigned to the transmission channel of the same data by the control means;
Detecting means for detecting communication quality for each subcarrier on the receiving side;
Notification means for notifying the transmission side of information of communication quality detected by the quality detection means;
Combining means for combining information transmitted by a plurality of subcarriers assigned to the transmission channel of the same data;
A multicarrier transmission / reception system comprising:

(Additional remark 13) The said control means allocates several subcarriers with low communication quality to the transmission channel of the same data based on the communication quality information notified from the said notification means. Multi-carrier transmission / reception system.

(Supplementary Note 14) A transmission device that transmits data by a multicarrier modulation / demodulation scheme in which a subchannel includes a plurality of subcarriers and includes a plurality of subchannels,
Control means for controlling the number of subchannels allocated to the transmission channel of the same data according to the communication quality of the subchannels;
Multiplexing means for multiplexing data assigned to a plurality of subchannels assigned to the same data transmission channel by the control means;
A transmission device comprising:

(Supplementary note 15) The transmission apparatus according to supplementary note 14, wherein the control means controls the number of subchannels assigned to a transmission channel of the same data based on communication quality information notified from a reception side.

(Supplementary note 16) The transmission apparatus according to supplementary note 15, wherein the control means allocates a plurality of subchannels with low communication quality to transmission channels of the same data.

(Supplementary note 17) Any one of Supplementary notes 14 to 16, wherein the multiplexing means changes the order and arrangement of bit sequences of a plurality of subchannels assigned to a transmission channel of the same data for each subchannel. The transmission device according to one.

(Supplementary note 18) Any one of Supplementary notes 14 to 16, wherein the multiplexing means changes the bit sequences of a plurality of subchannels assigned to the transmission channel of the same data for each subchannel by arranging them in the same order. The transmitting device according to any one of the above.

(Supplementary note 19) The transmission according to any one of supplementary notes 14 to 16, wherein the multiplexing means makes the sequence of bit sequences of a plurality of subchannels allocated to a transmission channel of the same data the same. apparatus.

(Supplementary note 20) A receiving device that receives data transmitted by a multicarrier modulation / demodulation scheme in which a subchannel includes a plurality of subcarriers and includes a plurality of subchannels,
Detection means for detecting communication quality for each subchannel;
Notification means for notifying the transmission side of information of communication quality detected by the detection means;
Combining means for combining information transmitted by a plurality of subchannels assigned to the transmission channel of the same data;
A receiving apparatus comprising:

(Additional remark 21) The notification means sends information including only the position of the subchannel with low communication quality and information including both the position of the subchannel with low communication quality and the communication quality of the subchannel to the transmission side. The receiving device according to appendix 20, wherein the notification is switched according to the length of the message.

(Supplementary note 22) The receiving apparatus according to supplementary note 20, wherein the notifying unit notifies a position of a subchannel with low communication quality.

(Supplementary note 23) The receiving apparatus according to supplementary note 20, wherein the notification means notifies both of the position of a subchannel with low communication quality and the communication quality of the subchannel.

(Supplementary note 24) The receiving device according to supplementary note 20, wherein the notification means notifies communication quality of all subchannels.

(Supplementary Note 25) A multicarrier transmission / reception system in which a subchannel includes a plurality of subcarriers and performs data transmission / reception by a multicarrier modulation / demodulation method including a plurality of subchannels,
Control means for controlling the number of subchannels allocated to the transmission channel of the same data in accordance with the communication quality of the subchannels on the transmission side;
Multiplexing means for multiplexing data assigned to a plurality of subchannels assigned to the same data transmission channel by the control means;
Detecting means for detecting communication quality for each subchannel on the receiving side;
Notification means for notifying the transmission side of information of communication quality detected by the quality detection means;
Combining means for combining information transmitted by a plurality of subchannels assigned to the transmission channel of the same data;
A multicarrier transmission / reception system comprising:

(Additional remark 26) The said control means allocates several subchannels with low communication quality to the transmission channel of the same data based on the information of the communication quality notified from the said notification means, Additional remark 25 characterized by the above-mentioned. Multi-carrier transmission / reception system.

  As described above, the transmission device, the reception device, and the multicarrier transmission / reception system according to the present invention are useful for a wireless communication system using a multicarrier modulation / demodulation method, and in particular, perform wireless communication between a base station and a mobile terminal. Suitable for mobile phone systems and terrestrial digital broadcasting systems.

FIG. 1 is a block diagram showing a configuration of a transmission apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the receiving apparatus according to the embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of data allocation by the multicarrier transmission / reception system according to the embodiment of the present invention. FIG. 4 is a flowchart showing the overall operation of the multicarrier transmission / reception system according to the embodiment of the present invention. FIG. 5 is a flowchart showing details of an operation for assigning data to subcarriers with low communication quality in the multicarrier transmission / reception system according to the embodiment of the present invention. FIG. 6 is an explanatory diagram showing an example of a configuration of low quality subcarrier information. FIG. 7 is an explanatory diagram showing another example of the configuration of the low quality subcarrier information. FIG. 8 is a flowchart showing main operations of the transmission apparatus according to the embodiment of the present invention. FIG. 9 is a flowchart showing main operations of the receiving apparatus according to the embodiment of the present invention. FIG. 10 is an explanatory diagram showing an example of data mapping in the transmission apparatus according to the embodiment of the present invention. FIG. 11 is an explanatory diagram showing another example of data mapping in the transmission apparatus according to the embodiment of the present invention. FIG. 12 is an explanatory diagram showing still another example of data mapping in the transmission apparatus according to the embodiment of the present invention. FIG. 13 is an explanatory diagram showing another example of data allocation by the multicarrier transmission / reception system according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmitting device 3 Receiving device 5 Low quality subcarrier information 11 Multiplexed data generation unit 20 Control unit 31 Antenna 32 Antenna switch 36 Quality detection unit 37 Multiplexed data synthesis unit 38 Control unit 39 Modulation / encoding unit 40 IFFT unit

Claims (10)

A transmission device that transmits data by a multicarrier modulation / demodulation method including a plurality of subcarriers,
Control means for controlling the number of subcarriers assigned to the transmission channel of the same data according to the communication quality of the subcarriers;
Multiplexing means for multiplexing data assigned to a plurality of subcarriers assigned to the transmission channel of the same data by the control means;
A transmission device comprising:   2. The transmission apparatus according to claim 1, wherein the control unit controls the number of subcarriers assigned to a transmission channel of the same data based on communication quality information notified from a reception side.   The transmission apparatus according to claim 2, wherein the control means allocates a plurality of subcarriers having low communication quality to a transmission channel of the same data.   The multiplexing means changes the order and arrangement of the bit sequences of a plurality of subcarriers assigned to the same data transmission channel for each subcarrier. The transmitting device described. A receiving device for receiving data transmitted by a multicarrier modulation / demodulation method composed of a plurality of subcarriers,
Detection means for detecting communication quality for each subcarrier;
A notification unit for notifying the transmitting side of information of the detected communication quality by pre-dangerous detecting means,
Combining means for combining information transmitted by a number of subcarriers according to the communication quality assigned to the transmission channel of the same data and notified by the notification means;
A receiving apparatus comprising: A receiving device for receiving data transmitted by a multicarrier modulation / demodulation method composed of a plurality of subcarriers,
Detection means for detecting communication quality for each subcarrier;
Information on only the position of the subcarrier with low communication quality detected by the detection means and information including both the position of the subcarrier with low communication quality and the communication quality of the subcarrier are sent to the transmission side. A notification means for switching according to the length and notifying the transmission side;
Combining means for combining information transmitted by a plurality of subcarriers assigned to the transmission channel of the same data;
Receiving device, characterized in that it comprises a. A receiving device for receiving data transmitted by a multicarrier modulation / demodulation method composed of a plurality of subcarriers,
Detection means for detecting communication quality for each subcarrier;
Notification means for notifying the transmitting side of the position of the subcarrier with low communication quality detected by the detection means;
Combining means for combining information transmitted by a plurality of subcarriers assigned to the transmission channel of the same data;
Receiving device, characterized in that it comprises a. A receiving device for receiving data transmitted by a multicarrier modulation / demodulation method composed of a plurality of subcarriers,
Detection means for detecting communication quality for each subcarrier;
Notifying means for notifying the transmitting side of both the position of the subcarrier with low communication quality detected by the detecting means and the communication quality of the subcarrier;
Combining means for combining information transmitted by a plurality of subcarriers assigned to the transmission channel of the same data;
Receiving device, characterized in that it comprises a. A multicarrier transmission / reception system that transmits and receives data using a multicarrier modulation / demodulation method composed of a plurality of subcarriers,
Control means for controlling the number of subcarriers allocated to the transmission channel of the same data according to the communication quality of the subcarriers on the transmission side;
Multiplexing means for multiplexing data assigned to a plurality of subcarriers assigned to the transmission channel of the same data by the control means;
Detecting means for detecting communication quality for each subcarrier on the receiving side;
A notification unit for notifying the transmitting side of information of the detected communication quality by pre-dangerous detecting means,
Combining means for combining information transmitted by a plurality of subcarriers assigned to the transmission channel of the same data;
A multicarrier transmission / reception system comprising:   The multi-carrier transmission / reception according to claim 9, wherein the control unit allocates a plurality of subcarriers having low communication quality to a transmission channel of the same data based on the communication quality information notified from the notification unit. system.

Images