WO2008029700A1

WO2008029700A1 - Communication terminal device, communication control device, communication system, and communication method

Info

Publication number: WO2008029700A1
Application number: PCT/JP2007/066876
Authority: WO
Inventors: Shoichi Shitara; Toshizo Nogami
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-09-04
Filing date: 2007-08-30
Publication date: 2008-03-13

Abstract

[PROBLEMS] To provide a technique for reporting, from a mobile station device to a base station device, reception quality information enabling scheduling considering a temporal fluctuation of a propagation path state in the base station device while suppressing the control information amount reported from the mobile station device. [MEANS FOR SOLVING PROBLEMS] A communication system employs the multicarrier communication method and performs communication between a base station device and a mobile station device by using a plurality of sub-channels. The mobile station device measures the reception quality in the signal received from the base station device (S61), generates reception quality information capable of performing scheduling reflecting the temporal fluctuation of the propagation path state according to at least two reception quality measurement results in the signals received at different timings for some sub-channels selected from the plurality of sub-channels (S62 to S65). The base station device schedules data to be transmitted to the mobile station device according to the reception quality information generated by the mobile station device (S67, S68).

Description

Specification

COMMUNICATION TERMINAL DEVICE, COMMUNICATION CONTROL DEVICE, COMMUNICATION SYSTEM AND COMMUNICATION METHOD

Technical field

[0001] The present invention employs a multicarrier scheme, and in a communication system that performs communication between a base station apparatus and a mobile station apparatus using a plurality of subchannels, reception from the mobile station apparatus to the base station apparatus. The present invention relates to a technology for reducing the amount of information related to quality.

Background art

[0002] In recent years, in the mobile radio communication field, in a multi-cell environment in which a plurality of cells, which are communication areas controlled by one base station apparatus, are arranged adjacent to each other, each cell uses the same frequency band. System development is progressing. This method is called a 1-cell repetitive mobile wireless communication method, and various studies have been made as a high-speed, large-capacity, low-bit-cost communication method.

[0003] As such a one-cell repetitive mobile radio communication scheme, OFDMA (Orthogonal Frequency Division Multiplexing) is an access scheme that uses OFDM (Orthogonal Frequency Division Multiplexing). A ccess (Orthogonal Frequency Division Multiple Access) The development capability of the 1-cell repetitive communication method adopting the communication method, and the 3GPP (3rd Generation Partnership Project), the 3rd generation mobile phone standardization project, is being advanced! (Non-Patent Document 1).

[0004] In the OFDMA communication system in Non-Patent Document 1, the mobile station apparatus and the base station apparatus use CQI (Channel Quality Indicator), which is information indicating the reception quality of the communication band used for downlink (downlink) wireless communication. To the base station apparatus, and the base station apparatus schedules packets allocated to the mobile station apparatus with good reception quality based on the CQI reported from each mobile station apparatus to improve the communication speed (throughput). A method is being considered.

[0005] The feedback of reception quality information from such a mobile station apparatus, that is, notification by uplink (uplink) radio communication improves the throughput of downlink radio communication by improving the utilization efficiency of downlink radio resources. On the other hand, used for feedback As the amount of control information for uplink wireless communication increases, there is a problem with reducing data communication efficiency in uplink wireless communication. An increase in the amount of control information for uplink wireless communication increases the information processing amount and transmission time of the mobile station device, leading to an increase in power consumption.

[0006] In Non-Patent Document 2, a method for reducing the amount of feedback information is proposed. Instantaneous CIR (Carrier to Interference) for all subchannels measured by a mobile station device without reporting information on all bands as feedback information. The amount of information for uplink communication is reduced by feeding back KQ instantaneous CIRs that have been selected from those that show high values from the power ratio (carrier-to-interference power ratio) to the base station as CQI information. .

Non-Patent Document 1: 3GPP TR25. 814, "Physical Layer Aspects for Evolved UTRA (Release 7) v.7.0.0", [online], [searched 24 July 2006], Internet http: / www 3gpp.org/ftp/Specs/archive/25― series / 25.814 / 25814-122.zip)

Non-Patent Document 2: Zhong— Hai Han and Yong— Hwan Lee, Opportunistic Scheduling with Partial Channel Information in OFDMA / FDD Sys terns, “Proc. VTC 2004 Fall, September 2004, p. 511—514

Disclosure of the invention

Problems to be solved by the invention

[0007] However, in the method of feeding back the CQI (CIR) of the instantaneous reception quality (propagation path characteristics) of the subchannel as shown in Non-Patent Document 2 described above, the feedback information notification and the actual allocation data Since it takes time to reach, there is a problem that it cannot cope with the time variation of the reception quality due to the fluctuation of the propagation path with the passage of time since the reception quality measurement. In addition, in the method of selecting and feedback K values with high reception quality for each measurement, the subchannel selected for each feedback period may differ. In this case, since the base station apparatus cannot continuously acquire CQI measured in the past, the base station apparatus cannot use the packet scheduling method that interpolates time variation! / ,! There's a problem.

[0008] Generally, a packet scheduling method in a base station apparatus includes a Proportional Fair The ness (PF) method, Maximum CIR (Max CIR) method, Round Robin (RR) method, etc. are known. The Max CIR method is a method of allocating data to the mobile station device with the highest CQI value from among the CQIs reported by each mobile station device, but in practice the mobile station device Depending on the time difference between the instantaneous force measurement report and the arrival of scheduled data after the decision, the reception channel condition fluctuated, and the best mobile station equipment was not always scheduled. In addition, the PF method is a method in which transmission is preferentially performed in descending order of the value (instantaneous CIR + average CIR) based on the ratio of the instantaneous CIR of each user and the average CIR measured in a certain interval before that. Therefore, CIR measured in the past needs to be reported from the mobile station device continuously for each subcarrier. That is, in the CQI feedback method that selects K values with high CQI values from the measured values in all subcarriers, CQI measured in the past may not be continuously fed back from the mobile station apparatus to the base station apparatus. . Therefore, there are cases where scheduling methods using CQI measured at multiple timings cannot be used! /.

FIG. 18 is a diagram showing an example of a propagation path environment at a certain time in the mobile station apparatus, (a) shows an example of a propagation path environment at a certain time T, and (b) is a time T force. It is a figure which shows an example of the propagation path environment after reception quality information report time progress. In FIG. 18, the horizontal axis indicates the frequency, and the vertical vehicle reason: 3lNR (Signal to Interference plus Noise power Ratio). The frequency axis direction is divided into sub-channels (SC) with several small bandwidths, and the SINR direction shows the average SINR value as well as the instantaneous SINR for each sub-channel. Here, Fig. 18 (b) is a diagram showing the channel environment after 1 CQI reporting time interval from time T in Fig. 18 (a). For example, considering the case where CQI values are fed back for the highest 5 subchannels over all 13 subchannels, SC4, 5, 6, 12, 13 are selected in Fig. 18 (a), whereas Fig. 18 (b ) (And SC5, 10, 11, 12, 13 will be selected, and SC10 and 11 will report the previous report value to the base station equipment! /, NA! / Scheduling methods that take account of the above cannot be adopted, and the subchannel area to be fed back is shaded in the figure.

FIG. 19 shows temporal changes in the propagation path environment of a certain subchannel in the mobile station apparatus. It is a figure. In the lower graph of FIG. 19, time is shown on the horizontal axis and SINR is shown on the vertical axis. In the time axis direction, the average SINR for each subframe (SF) divided by several time intervals is shown. The two scales in the upper part of FIG. 19 are diagrams illustrating examples of time-series situations in which the propagation path environment indicated in the subframe SF shown in the lower part of FIG. 19 is notified. Instant SIN

A

When R is used as feedback information, the signal transmitted from the base station apparatus after packet scheduling is performed based on the CQI information measured and reported by the mobile station apparatus when the time fluctuation of the propagation path condition of the mobile station apparatus is severe. Unlike the notified channel information, the channel condition at the time of receiving the signal has the problem that demodulation becomes impossible in a deteriorated channel environment. For example, the propagation path environment is measured (SF) using the reference signal transmitted from the base station device.

A

After that, the measured CQI data is fed back to the base station equipment (SF) and the base station equipment

C

The packet modulation method is determined based on the feedback data, and the time until the downlink transmitted data (SF) reaches the mobile station (RTT: Round Trip Time)

B

If the propagation path environment in the mobile station apparatus fluctuates during the round trip time), the mobile station apparatus cannot receive signals using the modulation method determined based on the measurement environment. In Fig. 19, 8PSK is selected as the value fed back to the base station equipment. In the reception environment after RTT, it is impossible to receive QPSK! /!

[0011] Also, as shown in FIG. 18, when the CQI value reported for each feedback timing is different, the CQI value of the same subchannel cannot be obtained continuously in the base station apparatus. The reception quality of the subchannel after RTT could not be estimated using the CQI value fed back last time and the CQI value fed back this time. In particular, the base station device could not cope with the case where the propagation path environment of the mobile station device changed greatly, such as when the mobile station device was moving at a high speed! / ヽ (the Doppler frequency was high! /).

[0012] The present invention has been made in view of such circumstances, and considers time variation of propagation path conditions in the base station apparatus while suppressing the amount of control information notified from the mobile station apparatus. It is an object of the present invention to provide a technique for notifying a base station device (communication control device) of reception quality information that enables scheduled scheduling from a mobile station device (communication terminal device).

Means for solving the problem (1) In order to achieve the above object, the present invention has taken the following measures. That is, the communication terminal apparatus according to the present invention communicates with the communication control apparatus using one or more subchannels among a plurality of usable subchannels, and the reception quality in at least one subchannel is the communication quality. A communication terminal device for notifying the control device, measuring the reception quality of the signal received from the communication control device, and receiving the measured reception quality measurement result, and receiving at at least two different timings Based on the received quality measurement result of the received signal, a received quality information generating unit for generating received quality information capable of performing scheduling reflecting the time variation of the propagation path condition, and transmitting the generated received quality information to the communication control device And a transmitting unit.

As described above, the communication terminal apparatus according to the present invention reduces the amount of reception quality information to be notified to the communication control apparatus, and reduces the time variation of the propagation path state of the communication terminal apparatus in the communication control apparatus. It provides a technique for performing the corresponding scheduling. According to the present invention, reception quality information that can perform scheduling reflecting time variation of propagation path conditions is generated based on reception quality measurement results of signals received at at least two different timings. This reception quality information is necessary for the communication terminal device to predict the time fluctuation of the propagation path condition in the communication control apparatus, or to predict the time fluctuation of the propagation path condition in the communication terminal apparatus. There may be cases where information is included. As a result, the reception quality information notified from the communication terminal apparatus to the communication control apparatus can be reduced, and the communication control apparatus can perform scheduling considering the time variation of the propagation path condition in the communication terminal apparatus. It is possible to improve the throughput of the entire system. Also, reducing the information fed back in the communication terminal device reduces processing load and communication time, leading to a reduction in power consumption.

[0015] (2) Further, in the communication terminal device of the present invention, the reception quality information generation unit includes a reception quality storage unit that stores a reception quality measurement result, a reception quality measurement result of a recently received signal, and a previous one. Based on the received quality measurement result of the channel, a predicted value of the propagation path condition is calculated, and based on the calculated predicted value of the propagation path condition, some subchannels are selected from the plurality of subchannels. The received quality information on the selected subchannels, the received quality information of the recently received signal and the previous received quality information. And a CQI information generation unit that generates data based on the signal quality measurement result.

[0016] In this way, the predicted value of the propagation path condition is calculated based on the reception quality measurement result of the recently received signal and the previous reception quality measurement result, and based on the calculated predicted value of the propagation path condition. And selecting some subchannels from the plurality of subchannels, and receiving the reception quality information on the selected partial subchannels from the reception quality measurement results of the recently received signal and the previous reception quality measurement results. Generate based on In other words, information related to the time variation of the propagation path condition predicted on the communication terminal apparatus side is fed back as reception quality information from the communication terminal apparatus to the communication control apparatus. As a result, the communication control apparatus continuously acquires the reception quality information on the subchannel and performs scheduling based on the prediction result of the time fluctuation of the propagation path condition even if! / ,! Can do.

[0017] (3) Further, in the communication terminal apparatus of the present invention, the reception quality information is information representing a predicted value of a propagation path condition calculated by the reception quality analysis unit.

[0018] Thus, since the information indicating the predicted value of the propagation path condition calculated in the reception quality analysis unit is fed back as reception quality information from the communication terminal apparatus to the communication control apparatus, the communication control apparatus Even when receiving quality information is continuously acquired, scheduling can be performed based on the prediction result of time fluctuation of propagation path conditions.

[0019] (4) In the communication terminal device of the present invention, the predicted value of the propagation path condition calculated by the reception quality analysis unit is a reception quality after a round trip time has elapsed. It is characterized by being! /

[0020] In this way, by predicting the reception quality after the lapse of the round 'trip' time, appropriate scheduling can be performed at the downlink timing when downlink communication is performed from the communication control apparatus to the communication terminal apparatus. To select the transmission format.

[0021] (5) In the communication terminal apparatus of the present invention, the reception quality measurement result used in the reception quality analysis unit for calculating the predicted value of the propagation path condition is a modulation parameter selected according to the reception quality. It is characterized by being. [0022] With this configuration, the communication terminal apparatus selects a modulation parameter considering the time variation of the propagation path condition and feeds it back to the communication control apparatus. It is possible to grasp various modulation parameters. As a result, the communication control apparatus can use the power S to perform communication using the modulation parameter corresponding to the reception quality of the communication terminal apparatus at the timing of transmitting transmission data to the communication terminal apparatus.

(6) Further, in the communication terminal apparatus of the present invention, the prediction value of the propagation path condition in the reception quality analysis unit is a modulation parameter.

[0024] With this configuration, the communication terminal apparatus selects a modulation parameter considering the time variation of the propagation path condition and feeds it back to the communication control apparatus. It is possible to grasp various modulation parameters. As a result, the communication control apparatus can use the power S to perform communication using the modulation parameter corresponding to the reception quality of the communication terminal apparatus at the timing of transmitting transmission data to the communication terminal apparatus.

[0025] (7) In the communication terminal apparatus of the present invention, the reception quality analysis unit predicts the reception quality after the lapse of the round 'trip' time, and modulates the parameter according to the predicted reception quality. A sub-channel is selected from the plurality of sub-channels based on the selected modulation parameter, and the CQI information generation unit selects the selected modulation parameter in the selected sub-channel. The reception quality information is used.

In this way, by predicting the reception quality after the lapse of the round “trip” time, appropriate scheduling is performed at the downlink timing at which downlink communication is performed from the communication control apparatus to the communication terminal apparatus. It becomes possible to select the transmission format.

[0027] (8) In the communication terminal device of the present invention, the reception quality information generation unit includes a reception quality storage unit that stores a reception quality measurement result, and a recent reception quality measurement obtained from a recent reception signal. Based on the result! /, Select some subchannels from the plurality of subchannels, and based on the recent reception quality measurement result and the previous reception quality measurement result for the selected subchannel, Generate fluctuation information indicating fluctuations in reception quality, And a CQI information generation unit that generates the reception quality information based on a recent reception quality measurement result and generated variation information.

[0028] Thus, based on the recent reception quality measurement result obtained from the latest received signal, a part of the subchannels is selected from the plurality of subchannels, and the recent reception is selected for the selected subchannel. Based on the quality measurement result and the previous reception quality measurement result, the fluctuation information indicating the fluctuation of the reception quality is generated, and the reception quality information is generated based on the recent reception quality measurement result and the generated fluctuation information. To do. Specifically, fluctuation information indicating fluctuations in reception quality in signals received at two different timings is fed back from the communication terminal apparatus to the communication control apparatus as reception quality information. As a result, even if the communication control apparatus does not continuously acquire the reception quality information related to the subchannel, it can use the fluctuation information and the latest reception quality related information to determine the propagation path condition in the communication terminal apparatus. Time fluctuations can be predicted, scheduling can be performed based on the predicted results, and the downlink transmission format can be selected.

[0029] (9) In the communication terminal apparatus of the present invention, the reception quality measurement result is a modulation parameter selected according to reception quality, and the variation information includes a recent modulation parameter and a previous modulation parameter. It is a parameter difference, and the reception quality information is information composed of recent modulation parameters and the variation information.

[0030] With this configuration, the communication control apparatus can predict the propagation path condition in the communication terminal apparatus after a certain time based on the fluctuation information and the modulation parameter corresponding to the latest reception quality. Thereby, the communication control apparatus can perform communication using the modulation parameter corresponding to the reception quality of the communication terminal apparatus at the timing of transmitting the transmission data to the communication terminal apparatus.

[0031] (10) Further, the communication control device of the present invention is a communication control device that communicates with a plurality of communication terminal devices using a plurality of sub-channels, and the reception quality information transmitted from the communication terminal device. Receiving information, information indicating at least one subchannel selected by the communication terminal device based on the reception quality information, information indicating a recent reception quality measurement result in the subchannel, and Fluctuation information indicating fluctuations in reception quality in the subchannel is acquired, and the acquired information indicating the subchannel and the maximum information are acquired. Based on information indicating a recent reception quality measurement result and the variation information, a reception quality estimation unit that predicts reception quality in consideration of temporal variation of the subchannel, and a reception quality predicted for each communication terminal device. And a scheduler unit that selects a subchannel used for transmission of data addressed to each communication terminal device.

In this way, based on the acquired information indicating the subchannel, the information indicating the latest reception quality measurement result, and the variation information, the reception quality in consideration of the temporal variation of the subchannel is predicted, and each communication terminal apparatus is On the other hand, since the subchannel used for transmission of data addressed to each communication terminal device is selected based on the predicted reception quality, it is possible to perform scheduling in consideration of the time variation of the transmission path condition in the communication terminal device. The throughput of the entire communication system can be improved. Also, reducing the information to be fed back in the communication terminal device will reduce the processing load and communication time, leading to a reduction in power consumption.

[0033] (11) The communication control apparatus of the present invention is a communication control apparatus that communicates with a plurality of communication terminal apparatuses using a plurality of subchannels, and includes reception quality information transmitted from the communication terminal apparatus. Receiving information, information indicating at least one subchannel selected by the communication terminal device based on the reception quality information, information indicating a modulation parameter in the subchannel, and modulation in the subchannel Fluctuation information indicating fluctuations in parameter level is acquired, and transmission using the subchannel is performed based on the acquired information indicating the subchannel, information indicating the modulation parameter, and the fluctuation information. A reception quality estimation unit that predicts a modulation parameter, and data addressed to each communication terminal apparatus based on the modulation parameter predicted for each communication terminal apparatus. It is characterized by and a scheduler section that selects a sub-channel used to transmit the

[0034] Thus, based on the acquired information indicating the subchannel, the information indicating the modulation parameter, and the variation information, the modulation parameter at the time of performing transmission using the subchannel is predicted, and is transmitted to each communication terminal apparatus. Since the subchannel used for transmission of data addressed to each communication terminal apparatus is selected based on the predicted modulation parameter, the modulation parameter corresponding to the reception quality of the communication terminal apparatus is transmitted at the timing of transmitting the transmission data to the communication terminal apparatus. Communication can be performed using a meter.

(12) Further, the communication system of the present invention is a communication system that employs a multi-carrier communication system and performs communication between a communication control device and a communication terminal device using a plurality of subchannels. The communication terminal apparatus measures the reception quality of the signal received from the communication control apparatus and outputs the measured reception quality measurement result, and the reception of the signal received at at least two different timings. A reception quality information generating unit that generates reception quality information capable of performing scheduling that reflects temporal fluctuations of propagation path conditions for some subchannels selected from the plurality of subchannels based on a quality measurement result; The communication control apparatus schedules data to be transmitted to the communication terminal apparatus based on the reception quality information generated by the communication terminal apparatus. It is characterized by having a scheduler section to perform!

[0036] As described above, the communication system according to the present invention reduces the information amount of the reception quality information notified from the communication terminal apparatus, and responds to the time variation of the propagation path state of the communication terminal apparatus in the communication control apparatus. The present invention provides a technique for feeding back information for scheduling from a communication terminal apparatus to a communication control apparatus. In this communication system, a subchannel to be fed back from the communication terminal device to the communication control device is selected, and at least two subchannels are selected based on reception quality measurement results of signals received at two different timings. For some of the subchannels, reception quality information that can be scheduled to reflect time fluctuations of the propagation path conditions is generated. In addition, this reception quality information can be used to select a downlink transmission format (such as a modulation parameter) reflecting the time variation of the propagation path condition in the communication control apparatus. Therefore, the reception quality information includes information required for the communication terminal apparatus to predict time fluctuation of the propagation path condition or information necessary for the communication control apparatus to predict time fluctuation of the propagation path condition in the communication terminal apparatus. It is sufficient that the communication control apparatus performs scheduling based on the reception quality information and includes information that can select the downlink transmission format. As a result, the reception quality information notified from the communication terminal device to the communication control device can be reduced, and the communication control device can be scheduled in consideration of the time variation of the propagation path condition in the communication terminal device. The overall communication system throughput. The ability to raise S. Also, reducing the information fed back in the communication terminal device will reduce the processing load and communication time, leading to a reduction in power consumption.

Yes

[0037] (13) Further, in the communication system of the present invention, based on a prediction result of a propagation path condition calculated using the at least two reception quality measurement results or a reception quality measurement result of a recently received signal. The sub-channel selection is performed! /.

[0038] As described above, since the subchannel is selected based on the prediction result of the propagation path condition calculated using at least two reception quality measurement results or the reception quality measurement result of the recently received signal, communication is performed. The reception quality information notified from the terminal device to the communication control device can be reduced, and the communication control device can be scheduled in consideration of the time variation of the propagation path condition in the communication terminal device. Improve overall throughput with power S.

[0039] (14) Further, in the communication system of the present invention, the reception quality information generation unit calculates the propagation path condition calculated by using the at least two reception quality measurement results for the reception quality information. It is characterized by being generated based on!

[0040] In this way, reception quality information is generated based on the prediction result of the propagation path condition calculated using at least two reception quality measurement results. In other words, information related to the time variation of the propagation path condition predicted on the communication terminal device side is fed back from the communication terminal device to the communication control device as reception quality information. As a result, the communication control apparatus continuously acquires the reception quality information on the subchannel, and performs scheduling based on the prediction result of the time fluctuation of the propagation path condition even in the case of a problem. Can do.

[0041] (15) In the communication system of the present invention, the reception quality information generation unit selects a modulation parameter corresponding to a prediction result of the propagation path condition as the reception quality information, and the scheduler unit In particular, scheduling the data based on the modulation parameter! /.

[0042] As described above, since the modulation parameter corresponding to the prediction result of the propagation path condition is selected as the reception quality information, and the data is scheduled based on the modulation parameter, communication is performed after a certain time on the communication control device side. Identify the appropriate modulation parameters in the terminal device Can. Thereby, the communication control apparatus can perform communication using the modulation parameter corresponding to the reception quality of the communication terminal apparatus at the timing of transmitting the transmission data to the communication terminal apparatus.

[0043] (16) Further, in the communication system of the present invention, the reception quality information generation unit generates a round '··· as a reception quality measurement result in a signal that recently received one of the reception quality measurement results. It is characterized by predicting the propagation path condition after the round trip time.

[0044] As described above, by predicting the propagation path condition after the lapse of the round 'trip' time, appropriate scheduling is performed at the downlink timing for performing downlink communication from the communication control apparatus to the communication terminal apparatus. It becomes possible to select the transmission format.

[0045] (17) Further, in the communication system of the present invention, the reception quality information generation unit receives a recently received signal and a previously received signal as a reception quality measurement result of at least two different timings. Using the reception quality measurement result in the signal, and generating the reception quality information based on the reception quality measurement result in the recently received signal and the fluctuation information indicating the difference between the two reception quality measurement results, A reception quality estimation unit for predicting a propagation path condition of the selected sub-channel based on the reception quality information, and the scheduler unit is configured to at least V based on the predicted propagation path condition. Scheduling the data! /

[0046] In this way, in the communication terminal apparatus, as the reception quality measurement result of at least two different timings, the reception quality information is obtained from the recently received signal and the reception quality measurement result of the previously received signal. It is generated based on the received quality measurement result in the received signal and the fluctuation information indicating the difference between the two received quality measurement results, and the communication control device determines the propagation path status of the selected subchannel based on the received quality information. Since the data is predicted and scheduled based on at least the predicted propagation path condition, the communication control device does not continuously receive the reception quality information related to the subchannel. And the latest reception quality-related information are used to predict time fluctuations in the propagation path conditions in the communication terminal equipment, based on the predicted results! Performs Jiyurin grayed, it is possible to select a transmission format of the downlink. [0047] (18) In the communication system of the present invention, the reception quality information generation unit selects a modulation parameter based on the reception quality measurement result, and the two reception quality measurement results are used as the variation information. Calculating a value indicating a difference between modulation parameters selected based on each of the parameters, and generating reception quality information based on the modulation parameter selected based on a reception quality measurement result in the recently received signal and the variation information; The reception quality estimation unit predicts a propagation path condition of the selected subchannel based on the modulation parameter and the variation information.

In this way, in the communication terminal apparatus, the modulation parameter is selected based on the reception quality measurement result, and a value indicating the difference between the modulation parameters selected based on each of the two reception quality measurement results is calculated as variation information. The reception quality information is generated based on the modulation parameter and the variation information selected based on the reception quality measurement result of the recently received signal, and the communication control device determines the subchannel selected based on the modulation parameter and the variation information. Since the propagation path condition is predicted, the communication control apparatus side can predict the propagation path condition in the communication terminal apparatus after a certain time based on the fluctuation information and the modulation parameter corresponding to the latest reception quality. Thereby, the communication control device can perform communication using the modulation parameter corresponding to the reception quality of the communication terminal device at the timing of transmitting the transmission data to the communication terminal device.

[0049] (19) Further, in the communication system of the present invention, the reception quality measurement result at the different timing is that at least one subframe as a unit of time is obtained from at least one different reception signal. As a niece!

[0050] In this way, since the reception quality measurement results at different timings are obtained from reception signals in which at least one subframe, which is a unit of time, is obtained, the communication control apparatus transmits transmission data to the communication terminal apparatus. Communication can be performed using a modulation parameter corresponding to the reception quality of the communication terminal apparatus at the transmission timing.

[0051] (20) Further, the communication method of the present invention is a communication method that employs a multi-carrier communication method and performs communication by assigning a plurality of communication terminal devices to a plurality of subchannels by a communication control device. The communication terminal apparatus receives a signal from the communication control apparatus, and at least two different timings for the subchannel selected from the plurality of subchannels. Based on the reception quality measurement result in the signal received by the mobile station, generates reception quality information that can be scheduled to reflect the time fluctuation of the propagation path condition, and the communication control device receives the reception quality information, It is characterized by scheduling data to be transmitted to the communication terminal device based on the received reception quality information.

As described above, the subchannel to be fed back from the communication terminal apparatus to the communication control apparatus is selected, and the plurality of subchannels are selected based on the reception quality measurement results in the signals received at at least two different timings. For some subchannels selected from the channel, reception quality information that can be scheduled to reflect the time fluctuation of the propagation path condition is generated. Also, it generates reception quality information that can select a downlink transmission format (modulation parameter, etc.) that reflects the time fluctuation of the propagation path condition. Accordingly, the reception quality information includes information that the communication terminal apparatus predicts the time fluctuation of the propagation path condition or information necessary for the communication control apparatus to predict the time fluctuation of the propagation path condition in the communication terminal apparatus. It is only necessary that the communication control device includes information that can be used for scheduling based on reception quality information and select a downlink transmission format. As a result, the reception quality information notified from the communication terminal apparatus to the communication control apparatus can be reduced, and the communication control apparatus can perform scheduling in consideration of the time variation of the propagation path condition in the communication terminal apparatus. Improve overall throughput with power S. Also, reducing the information fed back in the communication terminal device reduces the processing load and communication time, leading to a reduction in power consumption.

[0053] (21) Further, the communication method of the present invention is a communication method that employs a multi-carrier communication method, and in which a communication control apparatus allocates a plurality of communication terminal apparatuses to a plurality of subchannels to perform communication. The communication terminal apparatus receives a signal from the communication control apparatus, stores a reception quality measurement result of the received signal, and transmits a propagation path based on a latest reception quality measurement result and a previous reception quality measurement result. Based on the predicted propagation path status !, select some subchannels from the plurality of subchannels, and the predicted propagation path status in the selected partial subchannels. Reception quality information is generated based on the reception quality information, and the communication control device receives the reception quality information and schedules data to be transmitted to the communication terminal device based on the received reception quality information. ing.

[0054] In this way, the time variation of the propagation path condition is predicted based on the latest reception quality measurement result and the previous reception quality measurement result, and based on the predicted propagation path condition! / Some subchannels are selected from the subchannels, and reception quality information is generated based on the predicted channel conditions in the selected partial subchannels. In other words, information related to time fluctuations of the propagation path condition predicted on the communication terminal device side is fed back from the communication terminal device to the communication control device as reception quality information. As a result, the communication control apparatus can continuously acquire the reception quality information on the subchannels and perform scheduling based on the prediction result of the time variation of the propagation path condition even if! / ,! it can

[0055] (22) Further, the communication method of the present invention is a communication method that employs a multi-carrier communication system, and in which a communication control apparatus allocates a plurality of communication terminal apparatuses to a plurality of subchannels to perform communication. The communication terminal apparatus receives a signal from the communication control apparatus, stores a reception quality measurement result of the received signal, and selects a plurality of subchannels from the plurality of subchannels based on a recent reception quality measurement result. For the selected subchannel! /, To generate fluctuation information indicating fluctuations in reception quality based on the recent reception quality measurement result and the previous reception quality measurement result, and The communication control device generates reception quality information based on the measurement result and the generated variation information, the communication control device receives the reception quality information transmitted from the communication terminal device, and based on the reception quality information, communication The information indicating the subchannel selected by the terminal device, the information indicating the latest reception quality measurement result in the subchannel, and the fluctuation information indicating the change in the reception quality in the subchannel are acquired, and the acquired subchannel is acquired. Based on the received information, the latest reception quality measurement result information, and the variation information, the reception quality at the time of transmission using the subchannel is predicted, and the received quality is determined based on the predicted reception quality. Characterized by scheduling data!

In this way, based on the acquired information indicating the subchannel, the information indicating the latest reception quality measurement result, and the variation information, the reception quality in consideration of the temporal variation of the subchannel is predicted, and each communication terminal apparatus is Each communication terminal device based on the reception quality predicted for each Since the subchannel used for transmission of the addressed data is selected, it is possible to perform scheduling in consideration of the time variation of the transmission path condition in the communication terminal device, and the throughput of the entire communication system can be improved. Also, reducing the information to be fed back in the communication terminal device will reduce the processing load and communication time, leading to a reduction in power consumption.

The invention's effect

[0057] According to the present invention, while controlling the amount of control information notified from the communication terminal device, the communication control device performs communication control from the communication terminal device on reception quality information that enables scheduling in consideration of time fluctuation of the propagation path condition. The device can be notified. As a result, the communication control device can perform efficient scheduling in consideration of time fluctuations of the propagation path condition.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be described with reference to the drawings. In the drawings, components having the same configuration or function and corresponding parts are denoted by the same reference numerals, and description thereof is omitted.

Before describing the embodiments of the present invention, basic techniques and basic concepts of multicarrier communication used in the present invention will be described.

[0060] (Basic items of multi-carrier communication)

In the following description, OFDM is used as the digital modulation method and OFDMA communication method is used as the access method. A radio communication frame (hereinafter referred to as a frame) described below is divided into small pieces (resource blocks) so that it can be used by a plurality of mobile station apparatuses, and each resource block has a good communication environment. The communication speed is improved by allocating to.

[0061] (Description of frame)

FIG. 1 is a diagram illustrating an example of a frame configuration of downlink radio communication of a multicarrier communication system used in each embodiment of the present invention. The frame configuration shown here is the same as the frame configuration used in the general OFDMA communication system. The frame is divided into a certain time interval (frame interval) in the time direction into a plurality of frames and the frequency band is also divided into a plurality of subbands. It is divided into fixed bandwidths composed of subcarriers, and the divided frequency / time domain is shared by multiple mobile station devices. In this specification, one of the divided time intervals and frequency bands is called a resource block. A unit obtained by dividing a frame in the time domain (time axis direction) is sometimes called a subframe, and a unit divided in the frequency domain (frequency axis direction) is sometimes called a subchannel. In the example shown in Fig. 1, there are 12 resource blocks in the frequency axis direction and 20 resource blocks in the time axis direction. However, the present invention is not limited to the resource block division number and the resource block size. In addition, each mobile station apparatus uses these resource blocks in common, and each resource block is scheduled to a mobile station apparatus with a good propagation path environment, in particular, in order to improve communication characteristics (throughput). In addition, when there are a plurality of mobile station apparatuses performing communication with a small amount of data, it is possible to further divide and share one resource block.

[0062] (Adaptive scheduling)

Based on the reception quality information (CQI information) notified from each mobile station device, the base station device selects a mobile station device with good reception quality from multiple mobile station devices and stores data in multiple resource blocks. Assign and send. More specifically, the mobile station apparatus measures reception quality using a reference signal (also referred to as a pilot signal or preamble signal) transmitted in downlink radio communication, and converts it into a CQI format determined by the communication system. Then, it is transmitted to the base station device at regular intervals (1 subframe cycle at the shortest). Based on the CQI information reported from each mobile station device, the base station device determines the terminal to be allocated to each resource block, selects the optimal modulation method and coding rate that matches the reception quality, and generates data. After that, it is assigned to the specified resource block and transmitted. As a result, the communication speed (throughput) of the entire system can be improved. In other words, the bandwidth (resources and channels) that can be used in the system is divided into a plurality of parts, each of which is assigned to a user with good reception quality, and the throughput is improved.

[0063] When performing scheduling as described above, accurate reception quality information feedback from the mobile station device and feedback in a period that can follow temporal variations in the reception quality of the mobile station device are required. . Normally, it corresponds to the time variation of the reception quality of the mobile station device Therefore, the base station equipment compensates CQI information fed back at a fixed period in the time direction. For this reason, the mobile station device needs to continuously feed back CQI information for the same subchannel.

[0064] On the other hand, in multicarrier communication, a plurality of subchannels are set in the frequency direction, and the mobile station apparatus generally performs reception quality measurement for each subchannel and notifies the measured CQI information. is there. In addition, in order to perform scheduling that efficiently uses the entire frequency band, the base station apparatus follows the time variation of the reception quality information of each mobile station apparatus and performs interpolating of the reception quality information. Requires CQI information in the direction subchannel. As a result, the amount of uplink wireless communication control information from the mobile station device to the base station device increases, which may reduce the communication speed.

[0065] Therefore, in the present invention, a feedback method capable of dealing with temporal variations in reception quality at each mobile station apparatus during scheduling at the base station apparatus while reducing the amount of feedback information of reception quality is realized, Overcoming the above disadvantages.

[0066] In each embodiment of the present invention described below, the OFDMA communication scheme is assumed and details thereof are shown. However, the communication scheme is not limited to this, and the reception quality between the two communication apparatuses is not limited to this. The side that notifies the information is the mobile station apparatus, and the side that allocates the transmission data to each resource block based on the notified reception quality information is the base station apparatus. In addition, when two communication devices communicate with each other, each communication device may have both of the functions described above. The present invention can be applied to a plurality of communication devices that have a relationship in which any one of the plurality of communication devices has an allocation function and other communication devices can execute the reception quality notification function. Accordingly, the communication terminal device (terminal side) that notifies (feeds back) the reception quality information and allocates transmission data addressed to each communication terminal device to each resource block (each subchannel) based on the notified reception quality information. The present invention can be applied to any communication system that includes a plurality of communication devices having a relationship of communication control device (control side). Further, in each of the following embodiments, the force S mainly explains the relationship between the base station device and one mobile station device, and each of the plurality of mobile station devices existing in the cell has the same relationship as the base station device. Yes, each mobile station device shall operate. Further, in the description of each embodiment, description is made using SINR as an index indicating reception quality, but the index indicating reception quality is not limited to this. In addition to SINR, R ¾SI (Receive Signal Strength Indication), ≥> NR (Signal to Noise power Ratio), SIR (Signal to Interference power Ratio), CNR ( There are indicators related to the received signal or carrier power such as Carrier to Noise power Ratio (CIR), CIR, etc. In addition to this, BER (Bit Error Rate), PER (Packet Error Rate) Indicators indicating reception quality can be supplementarily used in relation to the success or failure of reception, such as: bucket error rate) and BLER CBlock Error Rate. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0068] (First embodiment)

In the first embodiment, the mobile station apparatus predicts time variation of the reception environment (propagation path condition) and feeds back the reception quality information (CQI information) corresponding to the predicted time variation of the reception environment to the base station apparatus. And the apparatus will be described. First, after explaining the outline of the flow of processing between the base station apparatus and the mobile station apparatus, the configuration and operation will be described in detail.

FIG. 2 is a sequence chart showing an example of a flow of processing performed by the base station apparatus and mobile station apparatus regarding feedback of CQI information in the present embodiment.

As shown in the figure, first, the base station apparatus transmits control information to the mobile station apparatus (S60). The control information specifies the band that the mobile station device is allowed to feed back and the number of subchannels that feed back CQI information. The band that is allowed to be fed back is a band to which data may be allocated in downlink wireless communication, and may be a method of designating a predetermined subchannel that is not necessarily designated by the band. However, the mobile station apparatus can adaptively determine the band that is allowed to be fed back and the number of subchannels to which CQI information is fed back and feed back. It is not always necessary to obtain the control information for each feedback opportunity. Such band limitation is specified by specifying a predetermined band according to the performance of the mobile station device, such as when the frequency band that can be used by the mobile station device can only be used for communication in a band narrower than the overall system bandwidth. Used for. [0071] Next, after receiving the control information, the mobile station apparatus performs reception quality measurement of a subchannel in a band designated by the base station apparatus or a subchannel desired to be scheduled by the mobile station apparatus (S61). ). The reception quality is generally measured using reference symbols, but it is also possible to use other known signals.

[0072] Further, the mobile station apparatus predicts the time variation of the measured reception quality, and calculates the reception quality after RTT (S62). The reception quality measured at the time of calculation and the reception quality data measured before that are used for the calculation. In general, a prediction method for obtaining a numerical value that is predicted outside the range of the data based on some known numerical data is referred to as outer casing, and there are many methods for the method, and in the present invention these methods are used. It is not intended to limit the outside method to a specific method. As the simplest method, there is a method called a primary outer cage or a straight outer cage. In addition, there are also methods using a quadratic curve and a method of outlay considering statistical probability.

Yes

[0073] Next, the mobile station apparatus determines the number of subchannels determined as system conditions from the reception quality after RTT calculated by the outer casing, or the number specified by the control information from the base station apparatus described above. Sub-channels are selected (S63). For example, a selection method such as selecting in the order of the best reception quality can be considered. After the selection, the modulation scheme and coding rate corresponding to the reception quality of each selected subchannel are determined (S64).

[0074] The mobile station apparatus generates feed knock information (CQI information) based on the modulation scheme and coding rate determined as described above (S65), and notifies the base station apparatus (S66). A more specific modulation method, coding rate selection method, feedback information generation method and format will be described later.

[0075] The base station apparatus performs scheduling based on the CQI information notified from each mobile station apparatus (S67), and processes data with the desired modulation scheme and coding rate and allocates data to the scheduled resource block (S68). ) And transmit (S69).

Next, the base station apparatus and mobile station apparatus that constitute the communication system of the present embodiment will be described. FIG. 3 is a block diagram showing a configuration example of the base station apparatus 100 according to the first embodiment of the present invention. FIG. 4 is a block diagram showing a configuration example of the mobile station apparatus 200 according to the first embodiment of the present invention. A base station apparatus 100 shown in FIG. 3 includes a transmission data processing unit 101, a mapping unit 102, an IFFT (Inverse Fast Fourier Transport) unit 103, a transmission unit 104, an antenna (antenna unit) 105, A receiving unit 106, an FFT (Fast Fourier Transport) unit 107, a received data processing unit 108, and a scheduler unit 109 are provided.

[0078] Mobile station apparatus 200 shown in FIG. 4 includes antenna (antenna unit) 201, receiving unit 202, and FFT unit.

203, reception data processing section 204, reception quality measurement section 205, transmission data processing section 206, mapping section 207, IFFT section 208, transmission section 209, and reception quality information generation section (reception quality information analysis / generation section) 220 Prepare.

[0079] First, each component configuring base station apparatus 100 will be described according to a data transmission procedure. The transmission data processing unit 101 processes the transmission data according to the scheduling control information notified from the scheduler unit 109 and generates data to be allocated to each transmission resource block. At this time, the transmission data is modulated and encoded according to modulation parameter (MCS: Modulation and Coding Scheme) information notified from scheduler section 109. The modulation parameter information (MCS information) is information that specifies at least one of a modulation scheme and a coding rate. In addition, a control signal for notifying the mobile station apparatus of control information including MCS information is generated and multiplexed with a transmission resource block together with transmission data addressed to the mobile station apparatus. However, the transmission data addressed to the mobile station apparatus and the control signal are not multiplexed in the same resource block, but the control signal can be multiplexed in a resource block different from the transmission data and notified to the mobile station apparatus 200. The control signal may be multiplexed by the mapping unit 102 described below. The control signal includes other control information such as information (ID) for identifying the mobile station apparatus, transmission data allocation information, payload size information, etc., using only modulation scheme (MCS) information.

[0080] As described above, the base station apparatus obtains information such as the designation information of subchannels for the mobile station apparatus to measure reception quality information and notify feedback, and information such as the number of subchannels to which CQI should be fed back. The data is input to the transmission data processing unit 101, performs data processing, and notifies the mobile station apparatus. Similarly, when transmitting data scheduled based on CQI information, the transmission data processing unit 101 performs the same processing and transmits the data to the mobile station apparatus.

[0081] Mapping section 102 transmits the transmission data according to the control information notified from scheduler section 109. The output from the data processing unit 101 is mapped to each transmission resource block. IFFT section 103 performs IFFT (Inverse Fast Fourier Transform) processing for converting the transmission data generated by mapping section 102 from a signal on the frequency axis to a signal on the time axis. The transmission unit 104 converts the transmission data output from the IFFT unit 103 from a digital signal to an analog signal, converts it to a radio frequency, and transmits it via the antenna 105.

[0082] Next, for each component constituting mobile station apparatus 200 shown in Fig. 4, base station apparatus

A description will be given in accordance with a procedure for receiving transmission data transmitted from 100 and transmitting transmission data transmitted from mobile station apparatus 200 to base station apparatus 100.

[0083] Receiving section 202 receives a signal transmitted from base station apparatus 100 via antenna 201, converts from a radio frequency to a baseband frequency, and then converts an analog signal to a digital signal. The FFT unit 203 performs FFT (Fast Fourier Transform) processing for converting the received signal from a signal on the time axis to a signal on the frequency axis.

Received data processing section 204 demodulates and decodes the signal that has been subjected to FFT processing. At this time, the reception data processing unit 204 first performs control signal processing in advance, acquires modulation parameter information and transmission data allocation information, and processes the data portion in accordance with these control information. The processed received signal is sent to reception quality measuring section 205. However, if the received data is data transmitted to another mobile station device, that is, if the D information is another mobile station device, the data portion must be processed. There is no need.

[0085] Reception quality measuring section 205 measures the reception quality of the received signal processed by reception data processing section 204. That is, reception quality measuring section 205 measures the reception quality of the signal received from base station apparatus 200. In this embodiment, the SINR for each resource block is measured as the reception quality. The measured reception quality measurement result is notified to reception quality information generation section 220. The reception quality measurement unit 205 generally measures the reception quality because it uses the signals (pilot signal, reference signal, and preamble signal) transmitted as the reference signal for data demodulation. The resource block does not necessarily need to be a resource block of data transmitted to itself, and measurement is performed using a reference signal of the resource block transmitted to another mobile station apparatus. [0086] Next, the procedure for generating CQI information for reporting to the base station apparatus from the measured reception quality information is shown below. Reception quality information generation section 220 generates CQI information (reception quality information) based on the reception quality measurement result measured by reception quality measurement section 205. In this specification, CQI information is information for notifying the base station apparatus 100 of propagation path status information of a part of resource blocks (hereinafter referred to as “selected resource blocks”) from a plurality of resource blocks (subchannels). It is. In the present embodiment, the reception quality information generation unit 220 is configured to use the plurality of subchannels based on two reception quality measurement results obtained by measuring each of a recently received signal and a signal received before the recently received signal. Select some subchannels (selected subchannels) from (resource block), and perform scheduling that reflects the time fluctuation of propagation path conditions in the selected subchannel (select downlink transmission format) CQI Generate information. In other words, the reception quality information generation unit 220 performs scheduling for the selected subchannel in which the base station apparatus reflects the time fluctuation of the propagation path condition, and transmits the downlink transmission format that reflects the time fluctuation of the propagation path condition ( CQI information that can select MCS) is generated. In the present embodiment, a case will be described in which the MCS information selected based on the reception quality in which time variation is predicted is notified as CQI information.

In the following description, as two reception quality measurement results at different timings, a reception quality measurement result for a recently received signal is used as a recent reception quality measurement result, and a reception quality result for a signal received before the most recent time is used. Will be described as the previous reception quality measurement result. In the present specification, description will be made assuming that processing for measuring reception quality of a signal is performed immediately after receiving the signal. Therefore, in the case of the reception quality measurement results at different timings, the timing at which the reception quality of the received signal is measured is different if the timing at which the signal is received is different. The specific configuration will be described below.

FIG. 5 is a block diagram illustrating an example of a detailed configuration of the reception quality information generation unit 220 of the present embodiment. As shown in FIG. 5, reception quality information generation section 220 includes reception quality storage section (CQI storage section) 221, reception quality analysis section (CQI analysis section) 222, and CQI information generation section 223. [0089] Reception quality storage section 221 is a storage area for storing the reception quality measurement result notified from reception quality measurement section 205, and measures reception quality in a signal received before (past) a recently received signal. The result (hereinafter referred to as “previous reception quality measurement result”) is stored. As the reception quality measurement result stored in the reception quality storage unit 221, the reception quality measurement result notified from the reception quality measurement unit 205 is written by the reception quality analysis unit 222. The reception quality storage unit 221 is not limited to the reception quality measurement result obtained by measuring the signal received immediately before as the reception quality measurement result for the signal received before the recently received signal, You may store the reception quality measurement result of measuring the signal received at the timing. The reception quality storage unit 221 may store the reception quality measurement result itself or may store information related to the reception quality measurement result. The information related to the reception quality measurement result is information selected based on the reception quality measurement result used in the reception quality analysis unit 222 (information that can be determined in accordance with the reception quality measurement result). And the like. The reception quality analysis unit 222 controls the contents, number, etc. of the reception quality related information (information about reception quality) stored in the reception quality storage unit 221.

[0090] Reception quality analysis section 222 inputs a reception quality measurement result (hereinafter referred to as "recent reception quality measurement result") of a signal recently received from reception quality measurement section 205, and inputs the latest received reception. Based on the quality measurement result and the previous reception quality measurement result stored in the reception quality storage unit 221, the reception quality after a certain time is calculated (estimated) (estimated time fluctuation of the propagation path condition) and calculated. Select some resource blocks (subchannels) from multiple resource blocks (subchannels) based on the received quality.

[0091] Here, the fixed time is when CQI information is reported from the mobile station apparatus to the base station apparatus, and data reflecting the CQI information is downlink transmitted and received from the base station apparatus to the mobile station apparatus. Means the shortest time. This time is generally called RTT. For the calculation of the reception quality after RTT (estimation of the time fluctuation of the propagation path condition), as described above, it is possible to take into account the fact that the outer shell is used and other statistics in the frequency axis direction. In the present invention, these prediction methods are not limited to a specific method, and any prediction method can be used as long as the prediction method can estimate the temporal variation of the reception quality when RTT elapses. Absent. [0092] Also, the reception quality analysis unit 222 has at least at least two reception quality measurement results obtained by measuring each of the signal received recently (currently) and the signal received before (in the past) the signal received recently (in the past). Based on the reception quality measurement results for signals received at two different timings, the reception quality after a certain period of time may be estimated. Based on the reception quality measurement results for three or more signals, estimation may be performed.

Note that reception quality analysis section 222 selects a resource block for creating CQI information from a plurality of resource blocks whose reception quality after RTT is predicted. Since some resource blocks are selected from a plurality of resource blocks having the same subframe, some subchannels are selected from a plurality of subchannels. Here, as an example of a specific selection method, select the highest number of predicted received quality (propagation channel conditions with estimated time fluctuation) and the top N subchannels (N is a natural number less than the number of subchannels). Method is used. The expected reception quality of the selected resource block is notified to the CQI information generation unit 223 in a desired format by a method described later.

[0094] Further, as another specific selection method of selecting N resource blocks from a plurality of resource blocks, a method of selecting N resource blocks continuous in the frequency direction with the best reception quality Another possible method is to select all resource blocks that have a reception quality that is equal to or higher than a certain threshold. The reception quality information generation unit 220 of this embodiment can adapt to these methods. In addition, the reception quality information generation unit 220 according to the present embodiment is not limited to these, and is used when reporting some reception quality information from a plurality of measurement reception quality information measured by the mobile station device to the base station device. All methods of some reception quality information can be applied. In addition, the desired format for notifying the expected reception quality is that the reception quality information in the selected resource block may be the measured reception quality measurement result itself (SINR in this embodiment), and the level is quantized. It may be modulation information (MCS) information corresponding to the displayed information and reception quality.

[0095] CQI information generation section 223 generates reception quality information based on the predicted reception quality (estimated propagation path condition time variation) in the resource block (subchannel) selected by reception quality analysis section 222.

Next, returning to FIG. 4, the mobile station apparatus regarding the CQI information transmission procedure in the mobile station apparatus The description will be made according to the configuration of The transmission data processing unit 206 generates data to be allocated to the scheduled transmission resource block when there is transmission data to be transmitted to the base station apparatus. Also, control information for notifying the base station apparatus 100 of the CQI information generated by the reception quality information generation unit 220 is generated and multiplexed on the transmission resource block.

The transmission resource block generated by the transmission data processing unit 206 is mapped by the mapping unit 207. IFFT section 208 performs IFFT (Inverse Fast Fourier Transform) processing for converting the transmission data generated by mapping section 207 from a signal on the frequency axis to a signal on the time axis. Transmitting section 209 converts the transmission data output from IFFT section 208 from a digital signal to an analog signal, converts it to a radio frequency, and transmits it to base station apparatus 100 via antenna 201.

[0098] Next, for each component constituting base station apparatus 100 shown in FIG. 3, mobile station apparatus

A description will be given in accordance with a data reception procedure for receiving transmission data transmitted by 200. The receiving unit 106 receives a signal transmitted from the mobile station device 200 via the antenna 105, converts the signal to a radio frequency power and a baseband frequency, and then converts the signal to an analog signal power and a digital signal. The FFT unit 107 performs FFT (Fast Fourier Transform) processing for converting the received signal from the signal on the time axis to the signal on the frequency axis.

[0099] Reception data processing section 108 demodulates and decodes the transmission data output from FFT section 107. Received data processing section 108 separates control information for CQI information notification from the data part, and sends CQI information to scheduler section 109.

[0100] Based on the CQI information notified from each mobile station apparatus 200, scheduler section 109 selects mobile station apparatus 200 to be allocated to all subchannels, and moves to be allocated to each subchannel. The station apparatus 200 and the MCS information are notified to the transmission data processing unit 101. In the present embodiment, the reception quality information generation unit 220 of the mobile station device 200 is notified of the MCS information selected based on the result of estimating the time fluctuation of the propagation path condition! / Unit 109 uses the notified MCS information to select an MCS that expects the reception quality in the mobile station apparatus after RTT.

[0101] Next, an operation related to the process of generating CQI information between the base station apparatus and each mobile station apparatus will be described. FIG. 6 shows the operation for generating CQI information in the mobile station apparatus of this embodiment. It is a flowchart which shows an example. FIG. 6 shows the operation of one mobile station apparatus among a plurality of mobile station apparatuses that communicate with the base station apparatus.

[0102] As shown in the figure, the receiving unit 202 of the mobile station apparatus first receives control information from the base station apparatus, and the received data processing unit 204 is requested to receive feedback from the base station apparatus V, It is determined whether there is a specified band (subchannel) and the number of feedback subchannels N (N is a natural number less than the total number of subchannels) (feedback related request) (SO). This determination does not necessarily need to be performed every feedback period, and may be fixedly determined when connecting to the base station apparatus, or may be updated at regular intervals. Also

It can also be omitted by predetermining systematically. The result determined by the reception data processing unit 204 is notified to the reception quality measurement unit 205.

[0103] When there is no feedback-related request from the base station device (No in SO), the mobile station device reception quality measurement unit 205 desires data allocation, that is, can receive transmission data from the base station device The reception quality of each subchannel is measured (S l). On the other hand, when there is a feedback-related request from the base station apparatus (Yes in SO), the reception quality measurement unit 205 of the mobile station apparatus measures the reception quality of the designated subchannel (S2). However, if the control information is not updated as described above and this determination is omitted (Yes in S0), the reception quality of the designated sub-channel is measured (S2).

[0104] Next, the reception quality information generation unit 220 (reception information analysis unit 222) of the mobile station apparatus measures the received reception quality measurement result (recent reception quality measurement result) for each subchannel and the past. The reception quality after RTT is predicted from the reception quality measurement result (previous reception quality measurement result) (S3). Thereafter, the reception information analysis unit 222 selects data of some subchannels from the reception quality data of all measurement subchannels (for example, selects N data higher than the expected reception quality value after RTT) (S4). Then, the modulation scheme and coding rate that can be received with the predicted reception quality of the selected subchannel are determined (S5).

[0105] Reception quality information generation section 220 (CQI information generation section 223) of the mobile station apparatus generates information indicating the measured subchannel, CQI information indicating the modulation scheme, and coding rate information (S6). The transmission unit 209 of the device notifies the base station device through uplink wireless communication (S7). [0106] FIG. 7 is a flowchart showing an example of an operation related to processing of CQI information in the base station apparatus of the present embodiment. FIG. 7 shows processing in downlink wireless communication from feedback information reception (CQI information reception) in the base station apparatus.

[0107] As shown in the figure, the base station apparatus receives feedback information from each mobile station apparatus by CQI uplink radio communication (S10), and the scheduler section 109 performs scheduling (Sll). In the present embodiment, scheduler section 109 performs scheduling using MCS information included in CQI information notified from the mobile station apparatus. The scheduler unit 109 may change the MCS information depending on the circumstances of the base station apparatus, which does not exclude the operation of performing scheduling by changing the MCS information notified from the mobile station apparatus.

[0108] Next, transmission data processing section 101 generates data with the modulation scheme and coding rate corresponding to the mobile station apparatus determined by scheduling, and mapping section 102 allocates each resource block (S12). Thereafter, the transmission section 104 of the base station apparatus transmits to each mobile station apparatus by downlink transmission (S13).

[0109] As described above with reference to Figs. 6 and 7, each mobile station device generates its own reception quality information and transmits it to the base station device. The base station device receives a plurality of mobile station devices. Based on the received reception quality information, a plurality of mobile station apparatuses existing in the cell are allocated to resource blocks. In the foregoing, the functions and operations of each component of the base station apparatus and mobile station apparatus have been described.

[0110] Next, a specific example of reception quality information notified from the mobile station apparatus to the base station apparatus will be described. First, Fig. 8 and Fig. 9 show examples of display methods when using modulation parameters (MCS) as CQI information for feedback. FIG. 8 shows a subchannel index, and FIG. 9 shows an index of a combination of a modulation scheme and a coding rate. Figure 8 shows an example in which an index is defined for each subchannel. FIG. 9 shows an example in which indexes corresponding to each of nine combinations of modulation schemes and coding rates are defined. By combining these and feeding back to the base station equipment, it is possible to notify the reception environment of the mobile station equipment. However, the example shown here is only an example, and of course, it is possible to cope with the use of a modulation scheme or coding rate different from the modulation scheme 'coding rate shown in FIG. As shown in Fig. 8, it is not always necessary to use one index per subchannel.

FIG. 10 is a diagram showing an example of reception quality measured in the mobile station apparatus. The horizontal axis is frequency and the vertical axis is SINR. Moreover, in the frequency axis direction, it is divided into subchannels (SC) with a constant frequency bandwidth, and corresponds to the band to which each resource block is allocated. The simplified SINRs on the vertical axis are 64QAM (64—Quadrature Amplitude Modulation), 16QAM (16—Quadrature Amplitude Modulation), 8PSK (8—Phase). Shift Keying: 8-phase phase modulation), QPSK (Quadrature Phase Shift Keying) and coding rate are combined to set the SINR threshold, which is used as the standard for selecting the modulation parameter (MCS). In addition to the example shown in FIG. 10, other modulation schemes such as BPSK (Binary Phase Shift Keying) and coding rate can be used.

[0112] The SINR shown in the figure is an example of a measured value (solid line) and an estimated value (dotted line) calculated by a certain estimation method, and is an average value for each subchannel, that is, for each resource block. (Average measured SINR and average predicted SINR). The reception quality measurement results used for estimation of time fluctuation of propagation path conditions (calculation of predicted reception quality) and the reception quality measurement results stored in the reception quality storage unit 221 are the same as those measured by the reception quality measurement unit 205. Even with data (for example, a value measured with accuracy in the frequency direction for each reference symbol), the processing value in the mobile station apparatus is reduced by averaging the measured values measured for 1S for each resource block. can do. On the other hand, when the accuracy of the estimated value is required even though the complexity is increased, the reception quality is measured in finer units in the frequency direction or the time direction, and the measured value is stored as it is without being processed. It is desirable to use it for estimation of time fluctuations.

[0113] If five resource blocks with better reception quality are selected from the average predicted SINR (dotted line), which is the estimation result, SC4, SC5, SC6, SC12, and SC13 are selected in the ί column shown in Fig. 10. Become. The selected subchannel is indicated by an arrow at the top in the figure. SC4, SC5, SC6, SC12, and SC13 are 64QAM 1/2, 64QAM 1/2, and 64QAM 1 / when the modulation parameter is selected from the average predicted SINR (estimated average received quality value) of the five selected resource blocks. 2, 64QAM 2/3, 64QAM 2/3. [0114] In the mobile station apparatus, reception quality analysis section 222 of reception quality information generation section 220 performs a process as described with reference to Fig. 10 and a subchannel for notifying the base station apparatus of reception quality information. The modulation parameter corresponding to the predicted reception quality is determined, and the determination result is notified to the CQI information generation unit 223 in association with the subchannel information (resource block information). The CQI information generation unit 223 receives the notification notified to the base station apparatus based on the determination result (MCS corresponding to the predicted reception quality) notified from the reception quality analysis unit 222 and the subchannel information (index indicating the subchannel). Generate quality information.

Specifically, using the control information shown in FIGS. 8 and 9, SC4 (0011), SC5 (010 0), SC6 (0 dish), SC12 (1011), and SC13 (1100) Feedback transmission is performed in association with (00 10), (0010), (0010), (0001), and (0001), each representing a modulation method.

[0116] Furthermore, when information for identifying the measurement time is necessary because the measurement timing and the CQI information report timing are not synchronized, the mobile station device uses time information such as a subframe number. In addition, it may be transmitted to the base station apparatus. The above is a description showing a specific example of the CQI information generation procedure.

[0117] As described above, the mobile station apparatus has only to notify the base station apparatus of reception quality information (CQI information) in some subchannels, so that reception quality information of all frequency subchannels is received. The overhead due to notification of control information in the uplink is reduced compared with the case of notifying of. In addition, by notifying the reception quality information considering the time variation (RTT) of the propagation path condition, even when the reception quality information of the same subchannel is not continuously reported from the mobile station apparatus to the base station apparatus, The station apparatus can acquire information that estimates the time variation of the propagation path condition. As a result, the base station apparatus can perform scheduling in consideration of the time variation of the propagation path condition, and can select an optimal combination of modulation scheme and coding rate.

[0118] Thus, according to the present embodiment, the mobile station apparatus considers the reception quality measurement result of the recently measured subchannel and the reception quality measurement result measured before that, and receives it after a certain time. In addition to estimating the quality (channel condition, reception quality characteristics), select a subchannel with a good reception quality from the subchannels from which the reception quality is estimated, and select the selected subchannel. The reception quality information of the channel can be notified to the base station apparatus. As a result, the mobile station apparatus can suppress the amount of control information compared to the case of notifying the reception quality information of all subchannels, reducing the overhead due to the notification of control information, and receiving after a fixed time. The power S is used to notify the base station equipment of the subchannel that is assumed to be of good quality.

[0119] Also, the base station apparatus receives the reception quality information that estimates the time variation of the propagation path condition in the selected subchannel, and thereby performs scheduling according to the time variation of the reception quality in the mobile station device. It becomes possible. In other words, by feeding back CQI information corresponding to a value (estimated reception quality) obtained by estimating the reception quality after a certain time on the mobile station apparatus side, the reception quality information in the subchannel cannot be continuously acquired in the base station apparatus. Therefore, it is possible to compensate for the case where temporal interpolation of reception quality is impossible. As a result, the base station apparatus can perform scheduling corresponding to temporal variations in reception quality of each mobile station apparatus. Therefore, the base station apparatus can assign each mobile station to a subchannel with good reception quality after a predetermined time from reception quality measurement. In addition, it is possible to flexibly cope with fluctuations in propagation path conditions in the mobile station apparatus, and it is possible to eliminate inconsistencies in modulation schemes due to propagation path fluctuations in the round trip time. Furthermore, by selecting a subchannel that is assumed to have good reception quality on the mobile station device side, the base station device limits the subchannels that are candidates for allocation in advance, thereby reducing the processing load. can do.

[0120] (Second Embodiment)

In the second embodiment, in the mobile station apparatus, a method for generating reception quality information (CQI information) by which the base station apparatus can infer the time variation of the reception environment (for estimation) and feeding back to the base station apparatus, and Indicates the device. In the first embodiment, when the mobile station apparatus feeds back the reception quality information to the base station apparatus, the reception quality characteristic after a predetermined time is estimated, and CQI information corresponding to the estimated value is notified. In this embodiment, instead of notifying the reception quality after a certain time estimated by the mobile station apparatus, the base station apparatus adds the information on the amount of change from the previous measurement to the reception quality information, so that the base station apparatus Information that can cope with time fluctuations is transmitted as feedback information. First, the base The outline of the flow of processing between the station apparatus and the mobile station apparatus will be described, and then the configuration and operation will be described in detail.

[0121] FIG. 11 is a sequence chart showing an example of the flow of processing performed by the base station apparatus and mobile station apparatus regarding feedback of CQI information in the present embodiment. The difference from the first embodiment shown in FIG. 2 is the feedback information creation procedure and format in the mobile station apparatus. This will be explained according to the procedure in Figure 11. First, control information is transmitted from the base station apparatus to the mobile station apparatus (S70). The control information specifies the number of subchannels that the mobile station device is allowed to feed back and the number of subchannels that feed back CQI information. Since the information included in the control information and the timing for acquiring the control information are the same as those in the first embodiment, description thereof is omitted.

[0122] After receiving the control information, the mobile station apparatus measures the reception quality of the subchannel specified by the base station apparatus or the subchannel desired to be scheduled by the mobile station apparatus (for S7 Do reception quality measurement). Is generally performed using reference symbols, but it is also possible to use other known signals.

[0123] Next, the mobile station apparatus selects a modulation method and a coding rate (downlink transmission format) based on the measured reception quality for each subchannel (S72). The mobile station apparatus stores the selected modulation scheme and coding rate in the mobile station apparatus, and the number of subchannels determined as system conditions or the number specified by the control information from the base station apparatus. A subchannel is selected (S73).

[0124] The mobile station apparatus calculates and calculates the difference between the modulation scheme corresponding to the reception quality information of a predetermined time ago and the coding rate (the modulation scheme and the coding rate stored in the previous mobile station device). Difference information (variation information) indicating the difference (variation difference) is generated (S74). In this embodiment, the reception quality characteristic (modulation method and encoding) measured as one subframe and stored in the mobile station apparatus as one subframe is set as the difference. Rate) and the base station equipment shall be notified. The process of notifying the base station apparatus of the variation value is one of procedures different from the first embodiment in the second embodiment, and will be described in detail later.

[0125] The mobile station apparatus generates feedback information (CQI information) based on the modulation scheme, coding rate, and difference information determined as described above (S75), and notifies the base station apparatus. (S 76). The base station apparatus performs scheduling based on the feedback information notified from each mobile station apparatus (S77), and data processed with a desired modulation method and coding rate is allocated to the scheduled resource block ( S78) and transmitted (S79).

[0126] The base station apparatus and mobile station apparatus constituting the communication system of the present embodiment will be described below. FIG. 12 is a block diagram showing a configuration example of the base station apparatus 130 of the second embodiment according to the present invention. FIG. 13 is a block diagram showing a configuration example of the mobile station apparatus 230 according to the second embodiment of the present invention.

12 includes a transmission data processing unit 101, a mapping unit 102, an IFFT unit 103, a transmission unit 104, an antenna 105, a reception unit 106, an FFT unit 107, a reception data processing unit 108, A reception quality estimation unit 131 and a scheduler unit 109 are provided. A reception quality estimation unit 131 is added to the configuration of the base station apparatus 100 of FIG.

Mobile station apparatus 230 shown in FIG. 13 includes antenna 201, receiving section 202, FFT section 203, received data processing section 204, reception quality measuring section 205, transmission data processing section 206, mapping section 207, IFFT section. 208, a transmission unit 209, and a reception quality information generation unit 240. A reception quality information generation unit 240 that performs different functions is installed instead of the reception quality information generation unit 220 of the mobile station apparatus 200 of FIG.

[0129] Hereinafter, each component configuring base station apparatus 130 shown in FIG. 12 and mobile station apparatus 230 shown in FIG. 13 will be described according to a data transmission / reception procedure. It should be noted that the constituent elements in FIG. 12 given the same reference numerals as those in FIG. 3 and the constituent elements in FIG. 13 given the same reference numerals in FIG. 4 are the same. The components related to the data transmission procedure in the base station apparatus 130 are the same as those in FIG.

[0130] Next, reception quality information generation section 240 will be described for each component included in mobile station apparatus 230 shown in FIG. The other components are the same as in Fig. 4 and will not be described.

[0131] A procedure for generating CQI information for reporting to the base station apparatus from the reception quality information measured in mobile station apparatus 230 is shown below. Reception quality information generation section 240 generates CQI information (reception quality information) based on the reception quality measurement result measured by reception quality measurement section 205. Specifically, the reception quality information generator 240 receives the recently received signal. Based on the reception quality measurement result (hereinafter referred to as “recent reception quality measurement result”), some subchannels (selected subchannels) are selected from the plurality of subchannels (resource blocks). Then, based on the latest reception quality measurement result for the selected subchannel and the reception quality measurement result for the signal received before the most recently received signal (hereinafter referred to as “previous reception quality result”), the reception is performed. Generate fluctuation information indicating quality fluctuations. Based on the recent reception quality measurement results and the generated fluctuation information, CQI information that can select the downlink transmission format that reflects the time fluctuation of the channel condition in the selected subchannel is generated. In this embodiment, as CQI information, the modulation information corresponding to the latest reception quality measurement result, and the fluctuation information indicating the difference in the level of the modulation parameter corresponding to each of the recent reception quality measurement result and the previous reception quality measurement result are shown. Explain the case of notification. A specific configuration will be described below.

FIG. 14 is a block diagram showing an example of a detailed configuration of the reception quality information generation unit 240 of the present embodiment. As shown in FIG. 14, reception quality information generation section 240 has reception quality storage section 241 and CQI information generation section 242.

Reception quality storage section 241 is a storage area for storing the reception quality measurement result notified from reception quality measurement section 205, and stores previous reception quality related information. The reception quality related information stored in the reception quality storage unit 241 is either the reception quality measurement result itself or information indicating the reception quality selected based on the reception quality measurement result (information that can be determined according to the reception quality measurement result). It is. The reception quality related information is written by the CQI information generation unit 242 based on the reception quality measurement result notified from the reception quality measurement unit 205. The reception quality storage unit 241 measures, as the previous reception quality related information, not only the reception quality measurement result obtained by measuring the signal received immediately before the recently received signal, but also the signals received at a plurality of past different timings. The received quality related information may be stored. The CQI information generation unit 242 controls the contents, number, and the like of the reception quality related information stored in the reception quality storage unit 241.

[0134] Based on the recent reception quality measurement result, the CQI generation unit 242 selects a plurality of subchannel powers, some subchannels, and connects the selected subchannels to the selected subchannels! / Reception quality measurement result and reception quality storage unit Based on previous reception quality related information stored in 241 Fluctuation information indicating fluctuations in reception quality (variation difference) is generated, and CQI information is generated based on recent reception quality measurement results and generated fluctuation information. The fixed time is the time from the previous mobile station device measuring the reception quality to the current time. That is, one subframe time interval. Therefore, a signal received before a recently received signal is received at a timing at least one subframe earlier than a recently received signal.

In this embodiment, CQI generation section 242 selects a modulation parameter (MCS) corresponding to the latest reception quality measurement result notified from reception quality measurement section 205, and sets the level of the selected modulation parameter. A part of the subchannels is selected from the plurality of subchannels based on the subchannels. Fluctuation information indicating the difference (variation difference) between the modulation parameter selected based on the recent reception quality measurement result and the modulation parameter selected based on the previous reception quality result for the selected subchannel (resource block). Generates CQI information based on the fluctuation information and the modulation parameter selected based on the recent reception quality measurement result, and displays the difference information from the reception quality before a certain time and the current reception quality. CQI information to be notified to is generated.

[0136] Also, as an example of a method of selecting some subchannels, a modulation parameter is selected based on the measured reception quality measurement result, and the modulation parameter level is high! /, Higher than subchannel. A method of selecting N (N is a natural number equal to or less than the number of subchannels) is used. However, if the modulation parameter level is the same, the method of selecting with priority the one that has a large difference from the previously measured reception quality (the better the improvement rate) or the subchannel of the previous selection. There is a way to choose. Further, as another specific selection method for selecting N resource blocks from a plurality of resource blocks, the same method as in the first embodiment can be applied.

[0137] In this embodiment, an example in which a modulation parameter is used as the information indicating the reception quality measurement result is described. However, the present invention is not limited to the modulation parameter, and a value indicating the reception quality itself such as SINR is used. It is also possible to use a value that can be selected according to the reception quality and that indicates the reception quality information to the base station apparatus. In this embodiment, the CQI information generation unit 242 also includes reception quality related information (modulation parameters) and two reception qualities. Although the case where CQI information is generated based on the fluctuation of related information (levels of two modulation parameters) has been explained, the fluctuation is not necessarily limited to the fluctuation of the value used as reception quality related information. . For example, even if a modulation parameter is used as reception quality related information and the variation difference is the variation difference of the reception quality measurement result itself, the time variation of the propagation path condition (time variation of the reception quality characteristic) is notified to the base station equipment. Any information that can be used.

[0138] Further, in this embodiment, the case where the modulation parameter is used as the reception quality related information has been described. However, the reception quality measurement result itself may be used, and reception quality other than the modulation parameter may be used. It can also be implemented using the information shown. When the reception quality measurement result itself is used, reception quality storage section 241 stores the previous reception quality measurement result, and CQI information generation section 242 selects some subchannels based on the latest reception quality measurement result. Select to generate fluctuation information indicating the difference between the latest reception quality measurement results and the previous reception quality measurement results.

[0139] Although the generated CQI information is transmitted to the base station apparatus, the CQI information transmission procedure in the mobile station apparatus is the same as in FIG.

Next, for each component related to the data reception procedure in the base station apparatus shown in FIG. 12, reception data processing for outputting CQI information to reception quality estimation section 131 and reception quality estimation section 131 different from FIG. A description will be given of the scheduler unit 109 using the result estimated by the unit 108 and the reception quality estimation unit 131. Other components are the same as those shown in FIG.

[0141] Reception data processing section 108 demodulates and decodes the transmission data output from IFFT section 107. Received data processing section 108 separates control information for CQI information notification from the data part, and sends CQI information to received quality estimation section 131.

[0142] Reception quality estimation section 131, based on the CQI information notified from each mobile station apparatus, time variation of the propagation path condition, here, actual data is allocated and transmission data reaches each mobile station apparatus. Estimate the instantaneous reception quality. The reception quality estimation unit 131 uses a recent reception quality measurement result (recent reception quality related information) and variation information (difference information) measured by each mobile station device included in the CQI information after a certain period of time. Estimate the reception quality of I think). The estimation method can also be realized by using another method such as a force s that can be considered by a method such as an outer shell as in the case where the mobile station apparatus performs in the first embodiment. The estimated channel condition (predicted reception quality) is sent to the scheduler unit 109.

[0143] Based on the estimated propagation path status (predicted reception quality) of each mobile station apparatus notified from reception quality estimation section 131, scheduler section 109 assigns V to all subchannels. The station device 230 is selected, and the mobile station device 230 to be assigned to each subchannel and the MCS information are notified to the transmission data processing unit 101. In the present embodiment, the reception quality estimation unit 131 estimates the time variation of the propagation path condition based on the variation information indicating the variation difference of the past reception quality generated by the reception quality information generation unit 240 of the mobile station device 200, and the estimation Based on the result, the MCS that predicted the reception quality in the mobile station device after a predetermined time is selected.

[0144] Next, an operation related to the 'generation of CQI information' process between the base station device and each mobile device will be described. FIG. 15 is a flowchart showing an example of an operation for generating CQI information in the mobile station apparatus of the present embodiment. FIG. 15 shows the operation of one mobile station apparatus among a plurality of mobile station apparatuses communicating with the base station apparatus.

[0145] As shown in the figure, the receiving unit 202 of the mobile station apparatus first receives control information from the base station apparatus, and the received data processing unit 204 is a band for which feedback is requested from the base station apparatus. It is determined whether or not there is a designation (subchannel) and the number of feedback subchannels N (N is a natural number equal to or less than the number of subchannels) (feedback related request) (S20). This determination may not be necessarily performed every feedback period, but may be fixedly determined when connecting to the base station apparatus, or may be updated at regular intervals. It can also be omitted by predetermining systematically. The result determined by the reception data processing unit 204 is notified to the reception quality measurement unit 205.

[0146] When there is no feedback-related request from the base station apparatus (No in S20), the reception quality measurement unit 205 of the mobile station apparatus desires data allocation, that is, transmits transmission data from the base station apparatus. The reception quality of the receivable subchannel is measured (S21). On the other hand, when there is a feedback-related request from the base station apparatus (Yes in S20), the reception quality measurement unit 205 of the mobile station apparatus measures the reception quality of the designated subchannel (S22). However, if the control information is not updated as described above and this determination is omitted (Yes in S20), the reception quality of the designated subchannel is measured (S22).

[0147] Next, reception quality information generation section 240 (CQI information generation section 242) of the mobile station apparatus performs modulation schemes corresponding to the measured reception quality measurement results (recent reception quality measurement results) for each subchannel. And a coding rate (modulation parameter) are selected and stored in the reception quality storage unit 241 inside the mobile station apparatus (S23). After that, the CQI information generator 242 selects some subchannels (for example, the top N) from a plurality of subchannels based on the combination of the modulation scheme and coding rate of each subchannel! (S24). Modulation method and coding rate (recent reception quality measurement result) of some selected subchannels, and a certain time before stored in the reception quality storage unit 241 (specifically, the sub-channel whose previous reception quality was measured) Data indicating the fluctuation level of the modulation parameter is calculated from the combination of the modulation scheme and coding rate (previous frame quality) (previous reception quality related information) to generate fluctuation information (S25).

[0148] CQI information is generated by associating the generated fluctuation information with the modulation parameters (combination of modulation scheme and coding rate) that are recent reception quality related information. The CQI information generation unit 242 of the mobile station apparatus generates CQI information indicating the calculated modulation parameter information and modulation scheme, coding rate, and difference information from the previous measurement (S26). The transmission unit 209 notifies the base station device through uplink wireless communication (S27). By using the CQI information format as described above, when the scheduling at the base station apparatus is performed, the reception quality condition (propagation path condition) at the time when the actually scheduled data reaches each mobile station apparatus is estimated. This makes it possible to communicate more efficiently.

FIG. 16 is a flowchart showing an example of an operation related to processing of CQI information in the base station apparatus of the present embodiment. FIG. 16 shows processing in downlink wireless communication from feedback information reception (CQI information reception) in the base station apparatus.

[0150] As shown in the figure, the base station apparatus receives feedback information from each mobile station apparatus through CQI uplink radio communication (S30), and the reception quality estimation section 131 transmits the propagation path after a certain time. The situation is estimated (S31). The propagation path condition (propagation path quality condition) after a certain time is the transmission data sent to each resource block based on the CQI information notified from each mobile station apparatus. This is the expected value of the reception quality of each mobile station apparatus when the transmission data is actually received by each mobile station apparatus.

[0151] Next, the scheduler section 109 performs scheduling based on the information on the propagation path condition after a predetermined time (S32), and the mobile station apparatus determined by scheduling performs the propagation after the predetermined time. Data is generated with a modulation scheme and coding rate corresponding to the road condition and assigned to each resource block (S33). Then, it transmits to each mobile station apparatus by downlink transmission (S34).

[0152] As described above with reference to FIGS. 15 and 16, each mobile station apparatus generates its own reception quality information and transmits it to the base station apparatus, and the base station apparatus includes a plurality of mobile station apparatuses. A plurality of mobile station apparatuses existing in the cell are allocated to resource blocks based on the reception quality information received from. In the above, the function 'operation of each component of the base station apparatus and the mobile station apparatus has been described.

[0153] Next, a specific example of the reception quality information notified from the mobile station apparatus to the base station apparatus will be described. An example of the display method when the modulation parameter (MCS) is used as CQI information for feedback is the same as that shown in Figs. In this embodiment, in addition to FIGS. 8 and 9, it is necessary to add variation information generated based on the latest reception quality measurement result and the previous reception quality measurement result. FIG. 17 is a diagram illustrating an example of level variation information between a modulation parameter corresponding to a recent reception quality measurement result and a modulation parameter corresponding to a previous reception quality measurement result. Figure 17 shows the fluctuation value (fluctuation difference) of the two modulation parameter levels and the index value indicating the fluctuation value. As shown in FIG. 17, when the level fluctuation exceeds a predetermined value (+3 or more and −3 or less in FIG. 17), the base station apparatus is notified of the predetermined value as a fluctuation difference.

[0154] For example, if the resource block that was QPSK 1/4 in the previous measurement becomes QPSK 2/3 in this measurement, the information shown in FIG. 17 is "+2" 010 "information is added and created as CQI information. The example shown here is an example, and it is possible not only to support the use of different modulation schemes and coding rates, but also the difference (variation information) from the reception quality of the previous measurement does not have to be a change in the MCS level. Any difference can be used as long as the mobile station apparatus can notify the base station apparatus of the time variation of the propagation path condition. Figure 17 As shown, the CQI information generation unit 242 can generate CQI information using a difference indicating a preset difference in difference as the difference in difference (difference). The above is an explanation showing a specific example of the CQI information generation procedure.

[0155] As described above, the mobile station apparatus only has to notify the base station apparatus of the reception quality information (C QI information) in the selected subchannel! /, So that the reception quality information of all frequency subchannels is notified. Compared to the case, the overhead due to control information notification in the uplink is reduced. In addition, the mobile station apparatus notifies the base station apparatus of fluctuation information (difference information) between the recent (current) reception quality and the reception quality before a certain time instead of performing the estimation in consideration of the RTT. As in the first embodiment, even when the reception quality information of the same subchannel is not continuously reported from the mobile station apparatus to the base station apparatus, the base station apparatus estimates time variation of the propagation path condition. It becomes possible to obtain information to be obtained. As a result, the base station apparatus can perform scheduling in consideration of the time variation of the propagation path condition, and can select an optimal combination of modulation scheme and coding rate.

[0156] Thus, according to the present embodiment, the mobile station apparatus performs, on the base station apparatus side, the reception quality measurement result of all subchannels measured recently and the reception quality measurement result measured before that. CQI information that makes it possible to estimate the reception quality (propagation channel condition, reception quality characteristics) after a certain period of time is transmitted to the base station device, and a part of the reception quality is good from the sub-channel node where the reception quality is measured. By selecting a subchannel, the base station apparatus control apparatus can be notified (feedback) of the difference information (variation information) between the reception quality, the latest reception quality, and the previous reception quality for the selected subchannel. As a result, the mobile station apparatus can suppress the control information amount (CQI information amount) compared to the case of notifying the reception quality information of all subchannels, and can reduce the overhead due to the control information notification.

[0157] Further, the base station apparatus receives CQI information (feedback information) to which difference information (fluctuation information) between the latest reception quality and the previous reception quality is added from the mobile station apparatus, so that time base ( Even if reception quality (information indicating reception quality) cannot be acquired continuously at every reception quality measurement timing, information that can be used to estimate reception quality will be acquired. Interpolation is possible. As a result, the base station device Therefore, it is possible to estimate the reception quality after a certain period of time and perform scheduling corresponding to the time variation of the reception quality at each mobile station, so that the reception quality is good after a certain period of time. It is possible to allocate mobile station devices to subchannels. Therefore, it is possible to flexibly cope with the fluctuation of the propagation path condition in the mobile station apparatus, and the force S is used to eliminate the mismatch of the modulation scheme due to the propagation path fluctuation of the round trip time.

[0158] Note that the present invention is not limited to this embodiment as long as the mobile station apparatus notifies the base station apparatus of information that can be used to estimate temporal variations in propagation path quality of subchannels (resource blocks). There is no. For example, two consecutive reception quality related information (reception quality measurement result itself or information indicating reception quality selected based on the reception quality measurement result) may be notified as reception quality information. In this case, reception quality information generation section 240 of the mobile station apparatus selects some subchannels from a plurality of subchannels based on the latest reception quality related information, and selects the selected subchannel! / Reception quality information is generated based on the latest reception quality related information and previous reception quality related information. The reception quality estimation unit 131 of the base station apparatus estimates the time variation of the propagation path condition based on the two reception quality related information included in the reception quality information. Thus, also in this case, it is possible to estimate the time fluctuation of the propagation path condition in the base station apparatus. In addition, the processing load on the mobile station device side can be reduced.

[0159] As described above, according to the preferred embodiment of the present invention, it is possible to perform scheduling in consideration of time fluctuations of the propagation path state in the base station apparatus while suppressing the amount of control information notified from the mobile station apparatus. It is possible to notify the base station device of the received quality information. As a result, the base station apparatus can perform efficient scheduling in consideration of the time variation of the propagation path condition. In addition, the overall system throughput is improved. Furthermore, by reducing the amount of reception quality information in the mobile station device, information processing time and transmission time are reduced, leading to a reduction in power consumption.

In each of the above embodiments, based on reception quality measurement results (recent reception quality measurement results and previous reception quality measurement results) for signals received at two different timings. As described in the case of generating reception quality information, the reception quality information generation unit 240 of the mobile station apparatus may generate CQI information based on reception quality measurement results in signals received at three or more different timings. . It is preferable to determine the number of reception quality measurement results to be used in consideration of the effect of increasing the processing load in the mobile station device and improving the accuracy of interpolation results.

Brief Description of Drawings

FIG. 1 is a diagram showing an example of a frame configuration of downlink radio communication of a multicarrier communication system used in each embodiment of the present invention.

2] A sequence chart showing an example of processing performed by the base station apparatus and mobile station apparatus regarding feedback of CQI information in the first embodiment.

FIG. 3 is a block diagram showing a configuration example of a base station apparatus according to the first embodiment of the present invention. 4] is a block diagram showing an example of the configuration of the mobile station apparatus of the first embodiment according to the present invention. 5] is a block diagram showing an example of the detailed configuration of the reception quality information generation unit of the first embodiment. is there.

FIG. 6 is a flowchart showing an example of an operation for generating CQI information in the mobile station apparatus of the first embodiment. Gakuen 7] is a flowchart showing an example of operations related to processing of CQI information in the base station apparatus of the first embodiment.

FIG. 8 is a diagram showing a subchannel index.

FIG. 9 is a diagram showing an index of a combination of a modulation scheme and a coding rate.

[10] FIG. 10 is a diagram showing an example of reception quality measured in the mobile station apparatus.

[Sen 11] is a sequence chart showing an example of a flow of processing performed by the base station apparatus and mobile station apparatus regarding feedback of CQI information in the second embodiment.

FIG. 12 is a block diagram showing a configuration example of a base station apparatus according to the second embodiment of the present invention. FIG. 12 is a block diagram showing a configuration example of a mobile station apparatus according to the second embodiment of the present invention. is there FIG. 14 is a block diagram illustrating an example of a detailed configuration of a reception quality information generation unit according to the second embodiment.

FIG. 15 is a flowchart showing an example of an operation for generating CQI information in the mobile station apparatus of the second embodiment.

FIG. 16 is a flowchart showing an example of an operation for generating CQI information in the mobile station apparatus of the second embodiment.

FIG. 17 is a diagram illustrating an example of level variation information between a modulation parameter corresponding to a recent reception quality measurement result and a modulation parameter corresponding to a previous reception quality measurement result.

FIG. 18 is a diagram showing an example of a propagation path environment at a certain time in a mobile station apparatus, (a) shows an example of a propagation path environment at a certain time T, and (b) is a reception quality information from time T. It is a figure which shows an example of the propagation path environment after report time passage.

FIG. 19 is a diagram showing temporal changes in the propagation path environment of a certain subchannel in the mobile station apparatus.

Explanation of symbols

100, 130 Base station equipment

101, 206 Transmission data processing section

102, 207 Mapping part

103, 208 IFFT Department

104, 209 Transmitter

105, 201 Antenna

106, 202 Receiver

107, 203 FFT section

108 Receive data processor

109 Scheduler section

131 Receive quality estimator

200, 230 Mobile station equipment

204 Receive data processing section

205 Reception quality measurement unit 220, 240 Reception quality information generator

221, 241 Reception quality storage unit 222 Reception quality analysis unit

223, 242 CQI information generator

Claims

The scope of the claims

[1] A communication terminal apparatus that communicates with a communication control apparatus using one or more subchannels among a plurality of usable subchannels and notifies the communication control apparatus of reception quality in at least one subchannel Because

A reception quality measurement unit that measures the reception quality of the signal received from the communication control device and outputs the measured reception quality measurement result;

A reception quality information generation unit that generates reception quality information that can perform scheduling reflecting time variation of propagation path conditions based on reception quality measurement results of signals received at at least two different timings;

A communication terminal device comprising: a transmission unit that transmits the generated reception quality information to the communication control device.

[2] The reception quality information generation unit includes:

A reception quality storage unit for storing reception quality measurement results;

Based on the reception quality measurement result of the recently received signal and the previous reception quality measurement result, a predicted value of the propagation path condition is calculated, and based on the calculated predicted value of the propagation path condition, a plurality of sub A reception quality analysis unit that selects a part of the subchannels from the channel; a reception quality measurement result of the recently received signal and a reception quality measurement result before that of the reception quality information of the selected part of the subchannels; The communication terminal apparatus according to claim 1, further comprising: a CQI information generation unit that generates based on:

3. The communication terminal apparatus according to claim 2, wherein the reception quality information is information representing a predicted value of a propagation path condition calculated by the reception quality analysis unit.

[4] The isi¾ terminal device according to claim 2, wherein the predicted value of the propagation path condition calculated by the reception quality analysis unit is reception quality after a round 'trip-time (Round Trip Time) has elapsed. .

[5] The communication according to claim 2, wherein the reception quality measurement result used for calculating a predicted value of the propagation path condition in the reception quality analysis unit is a modulation parameter selected according to the reception quality. Terminal device.

[6] The predicted value of the propagation path condition in the reception quality analysis unit is a modulation parameter. The communication terminal device according to claim 2.

[7] The reception quality analysis unit predicts the reception quality after the lapse of the round “trip” time, selects a modulation parameter according to the predicted reception quality, and determines the reception based on the selected modulation parameter. , Selecting some subchannels from the plurality of subchannels;

7. The communication terminal apparatus according to claim 6, wherein the CQI information generation unit uses the selected modulation parameter in the selected partial subchannel as the reception quality information.

[8] The reception quality information generation unit includes:

Based on the recent reception quality measurement result obtained from the latest received signal, a part of the subchannels is selected from the plurality of subchannels, and the recent reception quality measurement result and the selected subchannel are selected. CQI information generation that generates fluctuation information indicating fluctuations in reception quality based on the previous reception quality measurement results and generates the reception quality information based on the recent reception quality measurement results and the generated fluctuation information The communication terminal device according to claim 1, further comprising: a unit.

[9] The reception quality measurement result is a modulation parameter selected according to the reception quality, the variation information is a difference between the latest modulation parameter and the previous modulation parameter, and the reception quality information is the latest 9. The communication terminal apparatus according to claim 8, wherein the communication terminal apparatus is information composed of a modulation parameter of the first parameter and the variation information.

[10] A communication control apparatus that communicates with a plurality of communication terminal apparatuses using a plurality of subchannels.

A receiving unit for receiving reception quality information transmitted from the communication terminal apparatus; information indicating at least one subchannel selected by the communication terminal apparatus based on the reception quality information; and recent reception in the subchannel Information indicating a quality measurement result and fluctuation information indicating a change in reception quality in the subchannel are acquired, and the acquired information indicating the subchannel, the information indicating the latest reception quality measurement result, and the fluctuation information are acquired. A reception quality estimation unit that predicts reception quality in consideration of temporal variations of the subchannel, And a scheduler unit that selects a subchannel used for transmission of data addressed to each communication terminal device based on reception quality predicted for each communication terminal device.

[11] A communication control apparatus that communicates with a plurality of communication terminal apparatuses using a plurality of subchannels.

A reception unit that receives reception quality information transmitted from the communication terminal apparatus; information indicating at least one subchannel selected by the communication terminal apparatus based on the reception quality information; and a modulation parameter in the subchannel. Information indicating the variation of the modulation parameter level in the subchannel, and the subchannel based on the acquired information indicating the subchannel, the information indicating the modulation parameter, and the variation information. A reception quality estimator for predicting a modulation parameter at the time of transmission used;

And a scheduler unit that selects a subchannel used for transmission of data addressed to each communication terminal device based on a modulation parameter predicted for each communication terminal device.

[12] A communication system that employs a multi-carrier communication method and performs communication between a communication control device and a communication terminal device using a plurality of subchannels,

The communication terminal device

A reception quality measuring unit that measures reception quality in a signal received from the communication control device and outputs a measured reception quality measurement result; and

Based on the reception quality measurement results of signals received at at least two different timings, scheduling that reflects the time variation of the propagation path status for some subchannels selected from the plurality of subchannels! A reception quality information generation unit that generates reception quality information capable of performing

The communication control device includes:

A communication system comprising a scheduler section that schedules data to be transmitted to a communication terminal apparatus based on reception quality information generated by the communication terminal apparatus.

[13] The subchannel is selected based on a prediction result of a propagation path condition calculated using the at least two reception quality measurement results or a reception quality measurement result of a recently received signal. The communication system according to claim 12.

14. The reception quality information generation unit generates the reception quality information based on a prediction result of a propagation path condition calculated using the at least two reception quality measurement results. 12. The communication system according to 12.

[15] The reception quality information generation unit selects a modulation parameter corresponding to a prediction result of the propagation path condition as the reception quality information,

15. The communication system according to claim 14, wherein the scheduler unit schedules the data based on the modulation parameter.

[16] The reception quality information generation unit may use a propagation path after round trip time as a reception quality measurement result for a signal that recently received one of the reception quality measurement results. The communication system according to claim 14, wherein the situation is predicted.

[17] The reception quality information generation unit uses reception quality measurement results of recently received signals and previously received signals as reception quality measurement results of the at least two different timings. Generated based on fluctuation information indicating a difference between a reception quality measurement result of the recently received signal and the two reception quality measurement results;

The communication control device includes:

A reception quality estimation unit that predicts a propagation path condition of the selected subchannel based on the reception quality information! /

13. The communication system according to claim 12, wherein the scheduler unit schedules the data based on at least a predicted propagation path condition.

[18] The reception quality information generating unit selects a modulation parameter based on the reception quality measurement result, and uses the value indicating the difference between the modulation parameters selected based on the two reception quality measurement results as the variation information. Calculating and generating reception quality information based on the modulation parameter selected based on the reception quality measurement result in the recently received signal and the variation information; 18. The communication system according to claim 17, wherein the reception quality estimation unit predicts a propagation path condition of the subchannel selected above based on the modulation parameter and the variation information.

[19] The communication system according to claim 17, wherein the reception quality measurement results at different timings are obtained from reception signals that differ in at least one subframe as a unit of time.

[20] A communication method that employs a multi-carrier communication method, and in which a communication control apparatus assigns a plurality of communication terminal apparatuses to a plurality of subchannels to perform communication,

The communication terminal device

Receiving a signal from the communication control device;

For the subchannel selected from the plurality of subchannels, based on the reception quality measurement result of the signal received at at least two different timings, reception quality information that can perform scheduling reflecting the time variation of the propagation path condition is generated. The communication control device

Receiving the reception quality information;

A communication method characterized by scheduling data to be transmitted to a communication terminal apparatus based on received reception quality information.

[21] A communication method that employs a multi-carrier communication method, and in which a communication control apparatus assigns a plurality of communication terminal apparatuses to a plurality of subchannels to perform communication,

The communication terminal device

Receiving a signal from the communication control device;

Store the reception quality measurement result of the received signal,

Based on the latest reception quality measurement results and previous reception quality measurement results, the time fluctuation of the propagation path condition is predicted, and based on the predicted propagation path condition! / Select a subchannel,

Generate reception quality information based on the predicted propagation path conditions in the selected subchannels,

The communication control device includes: Receiving the reception quality information;

A communication method that employs a multi-carrier communication system and a communication control device performs communication by assigning a plurality of communication terminal devices to a plurality of subchannels,

The communication terminal device

Receiving a signal from the communication control device;

Store the reception quality measurement result of the received signal,

A part of the subchannels is selected from the plurality of subchannels based on the latest reception quality measurement result, and the selected subchannel is received based on the recent reception quality measurement result and the previous reception quality measurement result. Fluctuation information indicating fluctuations in quality is generated, reception quality information is generated based on the recent reception quality measurement result and the generated fluctuation information,

The communication control device includes:

Receiving the reception quality information transmitted from the communication terminal device;

Based on the reception quality information, information indicating a subchannel selected by the communication terminal apparatus, information indicating a recent reception quality measurement result in the subchannel, and variation information indicating a change in reception quality in the subchannel Based on the acquired information indicating the subchannel, the information indicating the recent reception quality measurement result, and the fluctuation information, and predicting the reception quality when performing transmission using the subchannel, The data is scheduled based on the received quality.