JP4903251B2 - Mobile station apparatus, base station apparatus, and communication method - Google Patents

Description

The present invention relates to a mobile station apparatus , a base station apparatus, and a communication method , and more particularly, to a mobile station apparatus , a base station apparatus, and a communication method that perform multicarrier communication with a base station apparatus .

  In OFDM transmission, the communication quality of each subcarrier may differ due to the influence of frequency selective fading (see FIG. 1). Furthermore, in downlink OFDM transmission, since the channel conditions differ for each terminal (UE), the base station (Node-B) reports communication quality from each UE, and only subcarriers with good communication quality are provided for each UE. You can select and assign transmission data. This allocation method is called frequency scheduling.

  In general, in order to perform frequency scheduling, each terminal needs to measure reception quality based on a known pilot signal transmitted from the base station, and report communication quality information (CQI) based on the measurement result to the base station. is there. However, when the number of subcarriers constituting an OFDM signal is large, if CQI reporting is performed for all subcarriers, there is a problem that the amount of CQI reporting becomes enormous, and uplink radio resources are wasted.

  Therefore, conventionally, various methods for reducing the amount of CQI reporting have been devised. For example, in Non-Patent Document 1, a relative value of reception quality in the time / frequency domain as shown in FIG. 1 is introduced to reduce the CQI report amount. Specifically, as shown in FIG. 2, the CQI absolute value is reported for chunk # 1. For the other chunks, the relative value (CQI relative value) of each chunk with respect to the CQI of chunk # 1 is reported. By doing so, it is possible to reduce the data transmission amount for reporting rather than reporting the CQI absolute value for all chunks. Here, “chunk” means a bundle of subcarriers that are continuous in the normal frequency direction. In particular, in scheduling of a base station apparatus, a two-dimensional (a predetermined number of subcarriers and a predetermined number of TTIs) This means a minimum unit to be assigned to one terminal device.

NTT DOCOMO3GPP standardization contribution: R1-050590

  However, the conventional OFDM transmission has the following problems. That is, first, since the CQI relative value is always obtained on the basis of the CQI in one chunk at the end with respect to the frequency, the number of bits prepared for reporting the CQI relative value is limited. Below, a frequency selective fading pattern that varies greatly cannot be expressed accurately. For example, as shown in FIG. 3, when the relative value of CQI is reported with reference to chunk 1, when the number of bits prepared to represent the relative value of CQI is 2, the chunk 5 and the chunk 6 Thus, if the CQI is separated from the CQI of the reference chunk 1, the prepared bit cannot represent the relative value of the CQI. That is, when the CQI of the chunk selected as the reference is largely different from the CQI of the other chunk, the accuracy of the CQI of the other chunk is reduced when the selection of the reference chunk is inappropriate. For this reason, there is a problem that the communication quality is deteriorated due to a decrease in accuracy of the CQI report value.

An object of the present invention is a mobile station apparatus , a base station apparatus, and a communication method for performing multicarrier communication, which improve the communication quality without reducing the accuracy of feedback information while reducing the amount of data for feedback A station apparatus , a base station apparatus, and a communication method are provided.

One aspect mobile station apparatus of the present invention, for each subcarrier group obtained by dividing a plurality of consecutive subcarriers in the frequency direction in the predetermined unit time domain, a calculation unit for calculating a CQI value indicating the communication quality is calculated and on the basis of the CQI value, a generation section that generates feedback information, have a, a transmitting means for transmitting the feedback information, the calculating unit, every one of which reflects the communication quality of the group sub-carrier A difference value between the CQI value and the CQI value for each subcarrier group is calculated for each subcarrier group, and the generation unit arranges the one CQI value at the head of the data string, and then the frequency The feedback information formed by arranging the corresponding difference values in order from the subcarrier group having the largest frequency or the smallest frequency is generated .
A base station apparatus according to an aspect of the present invention includes a transmission unit that transmits transmission data to a mobile station apparatus using a plurality of subcarrier groups obtained by dividing a plurality of subcarriers that are continuous in the frequency domain in a predetermined unit in the time domain. A reception unit that receives feedback information generated from a CQI value indicating communication quality calculated for each subcarrier group in the mobile station device, the feedback information transmitted from the mobile station device; A scheduling unit that performs scheduling of the transmission data according to the received feedback information. In the mobile station apparatus, one CQI value reflecting communication quality of all the subcarrier groups and the sub A difference value from the CQI value for each carrier group is calculated for each subcarrier group, and the reception unit CQI values are placed at the beginning of the data sequence, followed by the order from the largest or smallest the subcarriers of the frequency of the frequency, the difference value corresponding to receive the feedback information comprised disposed.
The communication method according to one aspect of the present invention includes a calculation step of calculating a CQI value indicating communication quality for each subcarrier group obtained by dividing a plurality of subcarriers that are continuous in the frequency domain in a predetermined unit in the time domain. A generating step for generating feedback information based on the CQI value; and a transmitting step for transmitting the feedback information. The calculating step includes one CQI reflecting the communication quality of all the subcarrier groups. A difference value between the value and the CQI value for each subcarrier group is calculated for each subcarrier group, and the generation step places the one CQI value at the head of the data string, The feedback information formed by arranging the corresponding difference values in order from the subcarrier group having the largest frequency or the smallest frequency is generated.
A communication method according to an aspect of the present invention includes a transmission step of transmitting transmission data to a mobile station apparatus using a plurality of subcarrier groups obtained by dividing a plurality of subcarriers that are continuous in the frequency domain in a predetermined unit in the time domain; A receiving step for receiving the feedback information transmitted from the mobile station device, feedback information generated based on a CQI value indicating communication quality calculated for each of the subcarrier groups in the mobile station device; A scheduling step for scheduling the transmission data according to the received feedback information, and in the mobile station apparatus, one CQI value reflecting the communication quality of all the subcarrier groups and the subcarriers A difference value from the CQI value for each group is calculated for each subcarrier group, and the receiving step includes: Serial one CQI value is placed at the beginning of the data string, followed by the order from the largest or smallest the subcarriers of the frequency of the frequency, the difference value corresponding to receive the feedback information comprised disposed.

According to the present invention, a mobile station apparatus , a base station apparatus, and a communication method for performing multi-carrier communication, which reduce the amount of data for feedback and improve communication quality without reducing the accuracy of feedback information A station apparatus , a base station apparatus, and a communication method can be provided.

The figure which shows the situation of the communication quality fluctuation of each subcarrier due to the influence of frequency selective fading The figure for demonstrating the production | generation system of the feedback information of the conventional mobile station apparatus The figure for demonstrating the production | generation system of the feedback information of the conventional mobile station apparatus Block diagram showing a configuration of a mobile station apparatus according to Embodiment 1 of the present invention. The figure with which it uses for description of the feedback information generation method of the mobile station apparatus of FIG. The figure with which it uses for description of the feedback information generation method of the mobile station apparatus of FIG. The figure with which it uses for description of the feedback information generation method of the mobile station apparatus of FIG. FIG. 2 is a block diagram showing a configuration of a base station apparatus according to Embodiment 1 The figure which uses for description of the other system of the feedback information generation of the mobile station apparatus of FIG. The figure which uses for description of the other system of the feedback information generation of the mobile station apparatus of FIG. The figure with which it uses for description of the feedback information generation method of the mobile station apparatus of FIG. Block diagram showing configuration of mobile station apparatus according to Embodiment 2 The figure where it uses for description of step size change of the mobile station apparatus of FIG. The figure which shows an example of a structure of the CQI information of Embodiment 2. Block diagram showing a configuration of a base station apparatus according to Embodiment 2 Block diagram showing a configuration of a mobile station apparatus according to Embodiment 3 The figure which uses for description of step size change of the mobile station apparatus of FIG. FIG. 9 is a block diagram showing a configuration of a base station apparatus according to Embodiment 3

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment, the same components are denoted by the same reference numerals, and the description thereof will be omitted because it is duplicated.

(Embodiment 1)
As shown in FIG. 4, mobile station 100 of Embodiment 1 includes RF receiving section 105, GI removing section 110, FFT section 115, demodulating section 120, error correction decoding section 125, demultiplexing section 130, A reception level measurement unit 135, a reference chunk determination unit 140, an MCS determination unit 145, a relative value calculation unit 150, a CQI information generation unit 155, a control information transmission control unit 160, an error correction coding unit 165, A modulation unit 170, an IFFT unit 175, a GI insertion unit 180, and an RF transmission unit 185 are included.

  The RF receiving unit 105 receives a signal transmitted from a base station apparatus 200 described later, and performs RF processing such as down-conversion.

  GI removal section 110 removes the guard interval from the received signal after RF processing, and outputs the result to FFT section 115.

  The FFT unit 115 receives the received signal after the guard interval removal from the GI removal unit 110 and performs an FFT process on the input signal. Then, FFT section 115 outputs the received signal after the FFT processing to reception level measurement section 135 and demodulation section 120.

  The reception level measurement unit 135 measures the reception level for each chunk using a pilot signal included in the reception signal after the FFT processing. Here, the “chunk” means a subcarrier group that is continuous in the frequency direction, a discontinuous subcarrier group, or a region that is specified by time and frequency that are composed of a plurality of subcarriers and TTIs. The chunk is used as a minimum unit of resources allocated to one mobile station (UE).

  The reference chunk determination unit 140 reports the absolute value of MCS as CQI information to the base station apparatus 200 described later according to a predetermined rule based on the reception level (for example, SINR) measured by the reception level measurement unit 135 ( Determine the reference chunk). The predetermined rule is, for example, a rule using a predetermined chunk as a reference chunk, a rule using a chunk having the highest reception level as a reference chunk, or the like. In Embodiment 1, it is assumed that the chunk with the highest reception level is determined as the reference chunk. Thus, by setting the chunk with the highest reception level as the reference chunk, the chunk with the best channel quality is used as the reference chunk. Therefore, the accuracy of the CQI information generated based on this chunk can be improved. In particular, since the relative value is a difference (relative value), if the difference step width is not within the fluctuation range of the propagation path, the CQI accuracy may decrease as the distance from the reference chunk increases. In general, when frequency scheduling is performed, resources are allocated to chunks with good CQI, and therefore information regarding chunks with good CQI is regarded as important. Therefore, for CQI information, it is desirable to improve the accuracy of information related to chunks with particularly good channel quality. In addition, since the chunk with the high reception level is used as a reference, the most reliable value is used as the reference, so the reliability of the relative value of other chunks obtained based on the reception level of this reference chunk is also high. Get higher.

  The MCS determination unit 145 determines the MCS corresponding to the reception level measured by the reception level measurement unit 135 for each chunk.

  Based on the reference chunk determined by the reference chunk determination unit 140 and the MCS for each chunk determined by the MCS determination unit 145, the relative value calculation unit 150 calculates the relative value of the MCS with respect to the adjacent chunk.

  Specifically, first, the relative value calculation unit 150 temporarily holds the absolute value of the MCS for the reference chunk and calculates and temporarily holds the relative value of the MCS with the adjacent chunk for the other chunks.

  As a method for obtaining the relative value of MCS between adjacent chunks, for example, as shown in FIG. 5, the relative value of MCS is obtained by changing the reference for obtaining the relative value sequentially in the frequency direction toward the reference chunk. In more detail with reference to FIG. 6, the chunk 5 having the highest reception level is determined as the reference chunk in the drawing. Therefore, in the chunks 1 to 4 having a frequency lower than that of the reference chunk 5, the relative MCS value of the chunk 4 with respect to the chunk 5 (negative value in the figure), the chunk 3 with reference to the chunk 4 The relative values of MCS are calculated in order. Further, in chunks 6 to 8 having a frequency higher than that of reference chunk 5, the relative value of MCS with chunk 6 relative to chunk 5, the relative value of MCS with chunk 7 relative to chunk 6, and so on. Calculated in order.

  The CQI information generation unit 155 uses the relative value of the MCS between adjacent chunks calculated by the relative value calculation unit 150, the absolute value of the MCS of the reference chunk, and the reference chunk information from the reference chunk determination unit 140. CQI information is generated.

  The generation of CQI information is performed as shown in FIG. That is, the CQI information generation unit 155 arranges the reference chunk number and the absolute value of the MCS of the reference chunk at the beginning of the data string, and subsequently follows the end-of-frequency chunk, that is, the chunk with the highest frequency or the highest chunk. CQI information is generated by sequentially arranging MCS relative values of adjacent chunks calculated in one direction in the frequency direction from a small chunk.

  Control information transmission control section 160 controls transmission of CQI information generated by CQI information generation section 155 to base station apparatus 200 described later.

  The CQI information output from the control information transmission control unit 160 is subjected to error correction coding by the error correction coding unit 165, modulated by the modulation unit 170, IFFT by the IFFT unit 175, and GI insertion. After the guard interval is inserted by unit 180, it is transmitted to base station apparatus 200 described later via RF transmission unit 185.

  Demodulation section 120 receives the received signal after the FFT processing, demodulates it according to the radio resource allocation information, and outputs the demodulated reception signal to error correction decoding section 125.

  Error correction decoding section 125 receives the demodulated received signal, performs error correction decoding according to the radio resource allocation information, and outputs the error corrected decoded signal to demultiplexing section 130.

  Separation section 130 receives the signal after error correction decoding, separates it into various information such as received data, radio resource allocation information, and CQI information, and outputs the radio resource allocation information to demodulation section 120 and error correction decoding section 125. To do.

  As shown in FIG. 8, base station apparatus 200 in Embodiment 1 includes RF receiving section 205, GI removing section 210, FFT section 215, demodulating section 220, error correction decoding section 225, and separating section 230. , CQI information receiving unit 235, CQI information analyzing unit 240, scheduling unit 245, control information transmission control unit 250, multiplexing unit 255, transmission data generating unit 260, pilot generating unit 265, and error correction coding. Unit 270, modulation unit 275, IFFT unit 280, GI insertion unit 285, and RF transmission unit 290.

  The RF receiving unit 205 receives a signal transmitted from the mobile station device 100 and performs RF processing such as down-conversion.

  The GI removal unit 210 removes the guard interval from the received signal after the RF processing, and outputs it to the FFT unit 215.

  The FFT unit 215 receives the received signal after the guard interval removal from the GI removal unit 210 and performs an FFT process on this input signal. Then, FFT section 215 outputs the received signal after the FFT processing to demodulation section 220.

  Demodulation section 220 receives the FFT-processed reception signal, demodulates it according to the radio resource allocation information, and outputs the demodulated reception signal to error correction decoding section 225.

  Error correction decoding section 225 receives the demodulated received signal, performs error correction decoding according to the radio resource allocation information, and outputs the error corrected decoding signal to demultiplexing section 230.

  Separation section 230 receives the signal after error correction decoding, separates it into various information such as received data, radio resource allocation information, and CQI information, and outputs the radio resource allocation information to demodulation section 220 and error correction decoding section 225. The CQI information is output to the CQI information receiving unit 235. The output CQI information is output to the CQI information analysis unit 240 via the CQI information reception unit 235.

  The CQI information analysis unit 240 has the above-described configuration of the CQI information, that is, the reference chunk number and the absolute value of the MCS of the reference chunk are arranged at the head of the data string, and subsequently the chunk at the end in the frequency direction. In other words, since the relative values of MCS of adjacent chunks calculated in one direction from the highest or lowest chunk to the reference chunk in the frequency direction are arranged in order, based on this CQI information The absolute value of MCS is calculated for all chunks. The absolute value of the MCS of each chunk is output to the scheduling unit 245.

  The scheduling unit 245 performs scheduling based on the absolute value of the MCS of each chunk, and outputs scheduling information to the control information transmission control unit 250. The scheduling information is output to the multiplexing unit 255 under the control of the control information transmission control unit 250.

  Multiplexer 255 receives and multiplexes transmission data from transmission data generator 260, pilot signals from pilot generator 265, and scheduling information from control information transmission controller 250. The multiplexed signal is subjected to error correction coding by an error correction coding unit 270, modulated by a modulation unit 275, subjected to IFFT by an IFFT unit 280, and a guard interval is inserted by a GI insertion unit 285. Is transmitted to the mobile station apparatus 100 via the RF transmission unit 290.

  In the above description, a case has been described in which the reference is sequentially changed from the reference chunk as a method of obtaining the relative value of MCS between adjacent chunks. However, the present invention is not limited to this, as shown in FIG. Even if the relative value of the MCS is obtained in one direction from the chunk with the lower frequency toward the larger chunk, the relative value of the MCS is obtained in the one direction from the chunk with the higher frequency toward the smaller chunk as shown in FIG. May be.

  In the above description, the MCS of each chunk is determined from the reception level measured by the mobile station apparatus 100, and the CQI information is generated from the absolute value of the MCS of the reference chunk and the relative value of the MCS of the adjacent chunk. I explained. However, the present invention is not limited to this, and the reception level measured without determining the MCS by the mobile station apparatus 100 may be used for the CQI information. That is, mobile station apparatus 100 generates CQI information using the absolute value of the reception level (for example, SINR) of the reference chunk and the relative value of the reception level of adjacent chunks, and the base station on the receiving side of this CQI information Scheduling may be performed by determining the MCS using the CQI information received by the apparatus 200.

  As described above, according to the first embodiment, mobile station apparatus 100 that performs multicarrier communication with base station apparatus 200 receives a plurality of subcarriers based on a known signal (a pilot signal from base station apparatus 200). A reception level measurement unit 135 that measures communication quality for each chunk (for example, SINR as a reception level), and control information transmission control that transmits feedback information (CQI information) based on the communication quality of each chunk to the base station apparatus 200. Unit 160 and a relative value for calculating a relative value of communication quality between adjacent chunks (for example, a relative value of SINR, a relative value of MCS corresponding to SINR) from communication quality of each chunk (for example, SINR as a reception level) The calculation unit 150 and the absolute value of the communication quality of the reference chunk (for example, the absolute value of SINR, MCS corresponding to SINR) An absolute value) and a relative value of communication quality between adjacent chunks (for example, a relative value of SINR, a relative value of MCS corresponding to SINR), and a CQI information generation unit 155 that generates feedback information (CQI information) , Provided.

  By doing this, feedback information is generated from the relative value of the communication quality between adjacent chunks. Therefore, for example, even in a communication situation where the communication quality varies greatly as shown in FIG. Since feedback information reflecting the fluctuation state of communication quality more accurately can be generated without increasing, the accuracy of feedback information can be improved while reducing the amount of data for feedback. As a result, since the base station apparatus 200 that receives the feedback information can perform scheduling and the like based on highly accurate feedback information, the communication quality of the mobile station apparatus 100 and the base station apparatus 200 can be improved. Further, by using a relative value of communication quality between adjacent chunks, a large change range of CQI can be covered with the same number of bits, and it can be expressed even in a range in which communication quality differs greatly from the reference chunk.

  Further, the mobile station apparatus 100 is provided with a reference chunk determination unit 140 that selects a chunk having the best communication quality (for example, SINR as a reception level) as the reference chunk.

  In this way, the chunk having the most reliable communication quality can be selected. Then, by transmitting the feedback information including the absolute value of the communication quality of the reference chunk to the base station device 200, the reliability of the absolute value of the communication quality of each chunk obtained by the base station device 200 converting from the feedback information. Therefore, the communication quality of the mobile station device 100 and the base station device 200 can be improved.

  In addition, the mobile station apparatus 100 is provided with an MCS determination unit 145 that determines an MCS related to each chunk based on the communication quality for each chunk measured by the reception level measurement unit 135, and the relative value calculation unit 150 is provided between adjacent chunks. The relative value of MCS is calculated, and the CQI information generation unit 155 generates CQI information from the absolute value of the MCS of the reference chunk and the relative value of the MCS between the adjacent chunks.

(Embodiment 2)
In Embodiment 1, the relative value of MCS was always reported in units of 1 MCS. On the other hand, in Embodiment 2, the reporting reference unit (step size) of the relative value of MCS is set according to the propagation status between the base station apparatus (Node-B) and the mobile station apparatus (UE). Change.

  As shown in FIG. 12, mobile station apparatus 300 according to Embodiment 2 includes a step size determining unit 310, a relative value calculating unit 320, and a CQI information generating unit 330.

  The step size determining unit 310 estimates a propagation state between the mobile station device 300 and a base station device 400 to be described later based on the reception level measured by the reception level measuring unit 135, and according to the propagation state, the MCS. The report standard unit (step size) of the relative value of is determined. The step size information is output to the relative value calculation unit 320.

  The relative value calculation unit 320 is based on the step size information determined by the step size determination unit 310, the reference chunk determined by the reference chunk determination unit 140, and the MCS for each chunk determined by the MCS determination unit 145. , CQI information is calculated.

  Specifically, first, the relative value calculation unit 320 temporarily holds the absolute value of the MCS for the reference chunk and calculates and temporarily holds the relative value of the MCS with the adjacent chunk for the other chunks. Then, the relative value calculation unit 320 converts the calculated relative value of the MCS of the adjacent chunk based on the step size information. For example, in FIG. 13, when the step size is 1 MCS and MCS 8 is the MCS of the reference chunk, the relative values when the MCS of the adjacent chunks are MCS 7 and MCS 6 are 1 and 2, respectively, but the step size is 2 MCS. In both cases, the relative value becomes 1, and this value becomes the relative value of the MCS of the adjacent chunk after the conversion. By increasing the step size in this way, even when the number of bits used to represent the relative value of MCS is limited, it is possible to follow large fluctuations in the relative value.

  The CQI information generation unit 330 calculates the relative value of MCS between adjacent chunks calculated by the relative value calculation unit 320, the absolute value of the MCS of the reference chunk, the reference chunk information from the reference chunk determination unit 140, and the step size. CQI information is generated using the step size information from the determination unit 310. Specifically, the data structure includes step size information in the CQI information shown in FIG. 7 (see FIG. 14).

  As shown in FIG. 15, base station apparatus 400 of Embodiment 2 has CQI information analysis section 410. The CQI information analysis unit 410 has the above-described configuration, that is, the data configuration including the step size information in the CQI information shown in FIG. 7 (FIG. 14), so that the CQI information is based on the CQI information. The absolute value of MCS is calculated for all chunks. Specifically, based on the step size information, inverse conversion is performed to the relative value before conversion, and the absolute value of MCS is calculated for all chunks from the relative value before conversion and the absolute value of MCS of the reference chunk. The absolute value of the MCS of each chunk is output to the scheduling unit 245.

  As described above, according to the second embodiment, mobile station apparatus 300 that performs multicarrier communication with base station apparatus 400 receives a plurality of subcarriers based on a known signal (a pilot signal from base station apparatus 400). A reception level measurement unit 135 that measures communication quality for each chunk (for example, SINR as a reception level), and control information transmission control that transmits feedback information (CQI information) based on the communication quality of each chunk to the base station apparatus 400 Unit 160 and a relative value for calculating a relative value of communication quality between adjacent chunks (for example, a relative value of SINR, a relative value of MCS corresponding to SINR) from communication quality of each chunk (for example, SINR as a reception level) The calculation unit 320 and the absolute value of the communication quality of the reference chunk (for example, the absolute value of SINR, MCS corresponding to SINR) An absolute value) and a relative value of communication quality between adjacent chunks (for example, a relative value of SINR, a relative value of MCS corresponding to SINR), and a CQI information generating unit 330 that generates feedback information (CQI information) , Provided.

  Further, the mobile station device 300 reports the relative value of the communication quality (for example, the relative value of SINR, the relative value of MCS corresponding to SINR) based on the measured communication quality (for example, SINR as the reception level). A step size determination unit 310 that determines a reference unit (step size) is provided, and a relative value calculation unit 320 calculates a converted relative value obtained by converting the relative value of the communication quality according to the reporting reference unit, and generates CQI information. The unit 330 may include an absolute value of communication quality of the reference chunk (for example, an absolute value of SINR, an absolute value of MCS corresponding to SINR), and a converted relative value (for example, converted relative value of SINR, MCS corresponding to SINR). The feedback information is generated from the conversion relative value) and the reporting reference unit.

  In this way, the reporting standard unit can be adaptively changed according to the communication quality, so even in a communication situation where the communication quality varies greatly, the communication quality does not increase without increasing the amount of information representing the communication quality. Therefore, it is possible to generate feedback information that more accurately reflects the fluctuation state of the data, and thus it is possible to improve the accuracy of the feedback information while reducing the amount of data for feedback. As a result, since the base station apparatus 400 that receives the feedback information can perform scheduling and the like based on highly accurate feedback information, the communication quality of the mobile station apparatus 300 and the base station apparatus 400 can be improved.

(Embodiment 3)
In Embodiment 1, the relative value of MCS was always reported in units of 1 MCS. On the other hand, in the third embodiment, based on the MCS determined from the reception level for each chunk of the pilot signal transmitted from the base station apparatus (Node-B), the reporting reference unit of the relative value of MCS ( Step size) is determined.

  As shown in FIG. 16, mobile station apparatus 500 of Embodiment 3 includes a step size determination unit 510, a relative value calculation unit 520, and a CQI information generation unit 530.

  The step size determination unit 510 determines a report reference unit (step size) of the relative value of MCS based on the MCS for each chunk determined by the MCS determination unit 145.

  Specifically, as shown in FIG. 17, the step size determining unit 510 determines a chunk having the largest MCS and a chunk having the smallest MCS from among the MCSs for each chunk determined by the MCS determining unit 145. Identify. Note that the mobile station device 500 reports the chunk having the maximum MCS and the chunk having the minimum MCS to the base station device 600 described later as an absolute value as a reference chunk. Then, the difference between the maximum chunk and the minimum chunk (maximum minimum MCS range) is divided into a range of numbers that can be expressed by the number of bits prepared to represent the correlation value of MCS of adjacent chunks. This divided range becomes the step size in the present embodiment. That is, the step size determination unit 510 calculates the step size by dividing the maximum / minimum MCS range into a number that can be expressed by the number of bits prepared to represent the MCS correlation value of the adjacent chunk. In the figure, since the number of bits prepared for representing the MCS correlation value of the adjacent chunk is 2, the number that can be expressed is 4, and the maximum and minimum MCS range is 8, the step size is 2 MCS. It has become. In addition, although it demonstrates as what makes a step size equal here, it is not limited to this, You may divide | segment unevenly. In particular, it is possible to accurately represent a range in which the reliability of the measurement value of the reception level is higher by finely dividing the range in which the reception level is high, that is, the level in which the MCS level is high and dividing the range in which the low level is large. Can be improved.

  The relative value calculation unit 520 is based on the step size information determined by the step size determination unit 510, the reference chunk determined by the reference chunk determination unit 140, and the MCS for each chunk determined by the MCS determination unit 145. , CQI information is calculated.

  Specifically, first, the relative value calculation unit 520 temporarily holds the absolute value of the MCS for the reference chunk and calculates and temporarily holds the relative value of the MCS with the adjacent chunk for the other chunks. Then, the relative value calculation unit 520 converts the calculated relative value of the MCS of the adjacent chunk based on the step size information.

  The CQI information generation unit 530 includes the relative value of MCS between adjacent chunks calculated by the relative value calculation unit 520, the absolute value of the MCS of the reference chunk, the reference chunk information from the reference chunk determination unit 140, and the step size. CQI information is generated using the step size information from the determination unit 510. Specifically, the data structure includes step size information in the CQI information shown in FIG. 7 (FIG. 14).

  As shown in FIG. 18, base station apparatus 600 of Embodiment 3 has CQI information analysis section 610. The CQI information analysis unit 610 has the above-described configuration, that is, the data configuration including the step size information in the CQI information shown in FIG. 7 (FIG. 14). The absolute value of MCS is calculated for all chunks. Specifically, based on the step size information, inverse conversion is performed to the relative value before conversion, and the absolute value of MCS is calculated for all chunks from the relative value before conversion and the absolute value of MCS of the reference chunk. The absolute value of the MCS of each chunk is output to the scheduling unit 245.

  As described above, according to the third embodiment, mobile station apparatus 500 that performs multicarrier communication with base station apparatus 600 receives a plurality of subcarriers based on a known signal (a pilot signal from base station apparatus 600). A reception level measuring unit 135 that measures communication quality for each chunk (for example, SINR as a reception level), and control information transmission control that transmits feedback information (CQI information) based on the communication quality of each chunk to the base station apparatus 600. Unit 160 and a relative value for calculating a relative value of communication quality between adjacent chunks (for example, a relative value of SINR, a relative value of MCS corresponding to SINR) from communication quality of each chunk (for example, SINR as a reception level) The calculation unit 520 and the absolute value of the communication quality of the reference chunk (for example, the absolute value of SINR, MCS corresponding to SINR) An absolute value) and a relative value of communication quality between adjacent chunks (for example, a relative value of SINR, a relative value of MCS corresponding to SINR), and a CQI information generation unit 530 that generates feedback information (CQI information) , Provided.

  Further, the MCS determination unit 145 that determines the MCS related to each chunk based on the measured communication quality for each chunk (for example, SINR as the reception level), and the MCS determination unit 145 determine the mobile station device 500. Based on the width between the maximum MCS and the minimum MCS of the MCS and the number of bits for representing the relative value of the communication quality between the adjacent chunks in the feedback information, the relative value of the communication quality (for example, corresponding to SINR) A step size determination unit 510 that determines a report reference unit (step size) of MCS), and a relative value calculation unit 520 converts the relative value of the communication quality according to the report reference unit. The CQI information generation unit 530 calculates the absolute value of the communication quality of the reference chunk (for example, corresponding to SINR). The absolute value of CS), the converted relative values (for example, converted relative values of MCS corresponding to SINR), generates the feedback information from said reporting reference unit.

  In this way, the reporting standard unit can be adaptively changed according to the communication quality, so even in a communication situation where the communication quality varies greatly, the communication quality does not increase without increasing the amount of information representing the communication quality. Therefore, it is possible to generate feedback information that more accurately reflects the fluctuation state of the data, and thus it is possible to improve the accuracy of the feedback information while reducing the amount of data for feedback. As a result, since the base station apparatus 600 that receives the feedback information can perform scheduling and the like based on highly accurate feedback information, the communication quality of the mobile station apparatus 500 and the base station apparatus 600 can be improved.

(Other embodiments)
In the first to third embodiments, the case where the chunk having the highest communication quality is mainly selected as the reference chunk has been described. However, the present invention is not limited to this. For example, the average value of MCS of all chunks is used. A near MCS chunk may be determined as a reference chunk. Further, the reference chunk may be selected randomly, or may be selected according to a certain pattern. Further, the base station may instruct different reference chunk reporting patterns between the mobile stations.

The mobile station apparatus , base station apparatus, and communication method of the present invention are mobile station apparatuses that perform multicarrier communication such as OFDM communication, and reduce the amount of data for feedback without reducing the accuracy of feedback information. This is useful for improving communication quality.

Claims (12)

A calculation unit that calculates a CQI value indicating communication quality for each subcarrier group obtained by dividing a plurality of subcarriers that are continuous in the frequency direction in a predetermined unit in the time domain;
A generating unit that generates feedback information based on the calculated CQI value;
A transmission unit for transmitting the feedback information;
Have
The calculation unit calculates, for each subcarrier group, a difference value between one CQI value reflecting the communication quality of all the subcarrier groups and the CQI value for each subcarrier group, and the possible difference The difference value is converted according to a predetermined step size obtained by dividing a range of values,
The generating unit arranges the one CQI value at the head of the data string, and then arranges the corresponding converted difference values in order from the subcarrier group having the highest frequency or the lowest frequency. Generating the feedback information including information identifying the step size, the feedback information ;
Mobile station device. The transmitter transmits the one CQI value reflecting the communication quality of all the subcarrier groups as an absolute value.
The mobile station apparatus according to claim 1. A receiving unit for receiving transmission data transmitted using the subcarrier group;
The mobile station apparatus according to claim 1 or 2 . The CQI value indicates MCS.
The mobile station apparatus in any one of Claim 1 to 3 . The calculation unit calculates a difference value of the CQI values between adjacent subcarrier groups for each subcarrier group.
The mobile station apparatus in any one of Claim 1 to 4 . Using a plurality of subcarrier groups obtained by dividing a plurality of subcarriers continuous in the frequency domain in a predetermined unit in the time domain, and a transmission unit that transmits transmission data to the mobile station device;
A feedback unit that is generated based on a CQI value indicating communication quality calculated for each subcarrier group in the mobile station device, and that receives the feedback information transmitted from the mobile station device;
A scheduling unit that performs scheduling of the transmission data according to the received feedback information;
Have
In the mobile station apparatus, a difference value between one CQI value reflecting the communication quality of all the subcarrier groups and a CQI value for each subcarrier group is calculated for each subcarrier group, and the possible difference The difference value is converted in accordance with a predetermined step size obtained by dividing a range of values, and the receiving unit arranges the one CQI value at the head of the data string, and subsequently has the highest frequency or the lowest frequency. Receiving the feedback information including the information specifying the step size, which is the feedback information in which the corresponding converted difference values are arranged in order from the subcarrier group;
Base station device. The receiving unit receives the one CQI value reflecting the communication quality of all the subcarrier groups as an absolute value;
The base station apparatus according to claim 6 . The scheduling unit determines an MCS of the transmission data according to the received feedback information.
The base station apparatus according to claim 6 or 7 . The CQI value indicates MCS.
The base station apparatus according to any one of claims 6 8. The receiving unit receives the feedback information generated based on a difference value of the CQI values between adjacent subcarrier groups calculated for each subcarrier group in the mobile station device;
The base station apparatus in any one of Claim 6 to 9 . A calculation step of calculating a CQI value indicating communication quality for each subcarrier group obtained by dividing a plurality of subcarriers continuous in the frequency domain in a predetermined unit in the time domain;
A generating step of generating feedback information based on the calculated CQI value;
A transmission step of transmitting the feedback information;
Have
The calculating step calculates a difference value between one CQI value reflecting the communication quality of all the subcarrier groups and the CQI value for each subcarrier group for each subcarrier group, and the possible difference The difference value is converted according to a predetermined step size obtained by dividing a range of values,
In the generation step, the one CQI value is arranged at the head of the data string, and the corresponding converted difference values are arranged in order from the subcarrier group having the highest frequency or the lowest frequency. Generating the feedback information including information identifying the step size, the feedback information ;
Communication method. A transmission step of transmitting transmission data to the mobile station device using a plurality of subcarrier groups obtained by dividing a plurality of subcarriers that are continuous in the frequency domain in a predetermined unit in the time domain;
A receiving step for receiving the feedback information transmitted from the mobile station device, feedback information generated based on a CQI value indicating communication quality calculated for each of the subcarrier groups in the mobile station device;
A scheduling step of scheduling the transmission data according to the received feedback information;
Have
In the mobile station apparatus, a difference value between one CQI value reflecting the communication quality of all the subcarrier groups and a CQI value for each subcarrier group is calculated for each subcarrier group, and the possible difference The difference value is converted in accordance with a predetermined step size obtained by dividing a range of values, and the receiving step is arranged such that the one CQI value is arranged at the head of the data string, and subsequently has the highest frequency or the lowest frequency. Receiving the feedback information including the information specifying the step size, which is the feedback information in which the corresponding converted difference values are arranged in order from the subcarrier group;
Communication method.

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