WO2008041632A1

WO2008041632A1 - Report information generation device, communication device, communication information generation method, and communication information generation program

Info

Publication number: WO2008041632A1
Application number: PCT/JP2007/068966
Authority: WO
Inventors: Takashi Onodera; Toshizo Nogami
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-10-04
Filing date: 2007-09-28
Publication date: 2008-04-10

Abstract

[PROBLEMS] To report channel quality information obtained from a reception state of each channel to a communication destination by using a difference between an interpolation value obtained by interpolation based on channel quality information on some channels and channel quality information on the respective channels, so as to generate report information which suppresses an information amount and improves accuracy of channel quality information restored according to the difference. [MEANS FOR SOLVING PROBLEMS] A report information generation device (400) generates report information according to channel quality information in each channel. The device (400) includes: an interpolation unit (401) which uses channel quality information in two or more channels selected from a plurality of channels so as to calculate an interpolation value for interpolating the channel quality information in other channels not selected; and a difference calculation unit (402) which generates report information according to a difference value indicating a difference between the calculated interpolation value and the channel quality information in the other channels and the channel quality information in the two or more selected channels.

Description

Specification

Notification information generation device, communication device, notification information generation method, and notification information generation

The present invention relates to a technology for generating notification information for notifying a communication destination of information related to a propagation path condition in a communication method in which communication is performed using a plurality of subcarriers.

Background art

[0002] In order to improve communication efficiency (total throughput and transmission rate of the system) in a communication system, modulation scheme, channel coding rate, error correction coding mode, spreading factor, number of code multiplexes, etc. according to the reception state. An adaptive modulation scheme for determining transmission power or a combination thereof (hereinafter referred to as a modulation parameter) has been studied (see Non-Patent Document 1 and Non-Patent Document 2).

In a communication system adopting an adaptive modulation scheme, the following channel states or modulation parameters selected according to these channel states are notified to the other party of communication as information obtained from the state of reception: There is a need to.

• Received Signal Power to Noise Power Ratio (SNR), • Received Signal Power to Interference Power Ratio (SIR), • Received Signal Power to Interference Power and Noise Power Ratio (SINR) to Interference plus Noise power Ratio;

• Carrier-to-noise power ratio (CNR),

• Carrier power to interference ratio (CIR),

• Carrier power to interference power and noise power ratio (CINR: Carrier to Interference noise power ratio),

• Desired signal power to undesired signal power ratio (DUR: Desired signal to Undesired power ratio),

• Average received energy to noise power density ratio (E / N) per symbol,

s 0

• Average received energy to noise power density ratio (E / N) per bit, • Average received energy to interference power density ratio (E / 1) per symbol,

s 0

• Average received energy to interference power density ratio (E / \) per bit.

b 0

For example, it is composed of a base station apparatus and a terminal apparatus, and communication from the base station apparatus to the terminal apparatus

(Hereinafter referred to as downlink) and in a system employing frequency division duplex (hereinafter referred to as “FDD”) in communication from a terminal apparatus to a base station apparatus (hereinafter referred to as uplink). When applying adaptive modulation to the downlink, the following system configuration is possible.

(1) The terminal apparatus estimates the channel state from the downlink received signal, and notifies the base station apparatus of the estimated channel state as uplink notification information. The base station apparatus selects a modulation parameter for data destined for the terminal apparatus in the downlink based on the notification information to perform adaptive modulation, and the selected modulation parameter is selected prior to transmission of the adaptively modulated data. Is notified to the terminal apparatus as downlink notification information.

(2) The terminal device estimates the channel state from the downlink received signal, selects the modulation parameter for transmission data addressed to the own terminal device on the downlink based thereon, and selects the selected modulation The parameter is notified to the base station apparatus as uplink notification information, and the base station apparatus adaptively modulates data directed to the terminal apparatus in downlink based on the modulation parameter, and transmits the adaptively modulated data. The selected modulation parameter is previously notified to the terminal device as downlink notification information.

[0007] In the present specification, in the case of simply describing as notification information, one or both of uplink notification information and downlink notification information will be indicated. In addition, a system that compares CIR obtained from the latest downlink reception signal with the total sum of notification information in the past, and reports binary information as increase or decrease as uplink notification information Proposed! / (See Non-Patent Document 3).

FIG. 17 is a block diagram showing an example of a configuration of a notification information generating apparatus 900 for generating conventional notification information. The determination unit 901 inputs the CIR measurement value measured from the received signal, and outputs the CIR measurement value to the accumulator 902 at the same time as outputting the CIR measurement as notification information at the first notification. Furthermore, the determination unit 901 inputs the stored value stored in the accumulator 902 and stores the value stored in the! The stored value is compared, and when the CIR measurement value is larger, the notification information “UP” is output, and at the same time, a value (addition result) obtained by adding 0.5 dB to the stored value is output as the accumulator 90 2. If the measured value of the CIR is smaller, the notification information of "DOWN" is simultaneously output, and at the same time, a value (addition result) obtained by adding -0.5 dB to the stored value is output as an accumulator 90 2. If the stored value is the same, output the CIR measurement value

The accumulator 902 stores the CIR measurement value or the addition result input from the determination unit 901, and outputs the stored value to the determination unit 901. For example, in a multicarrier communication system that transmits information using a plurality of subcarriers, the subcarrier modulation can be further improved by performing adaptive modulation for each subcarrier or for each block consisting of a plurality of subcarriers. An adaptive modulation scheme has been studied (see Non-Patent Document 4 and Non-Patent Document 5).

In the subcarrier adaptive modulation scheme in such a multicarrier communication system, it is necessary to notify the communication partner apparatus of information obtained from the reception state for each subcarrier or each subcarrier block.

[0011] In a multicarrier communication system, CSI (Channel State Information), which is information obtained from the reception state, is obtained by grouping a plurality of subcarriers and subtracting the average value of CSI in the group from the original CSI Let the new CSI be the group, divide the group into multiple subgroups, calculate the average value for each subgroup in the same way and subtract from the original CSI! A scheme has been proposed in which it is repeated in subgroups and the average value obtained in each layer is updated and notified in a different cycle for each layer (see Non-Patent Document 6).

Also, Orthogonal Frequency Division Multiplexing (Orthogonal), which is one of multi-carrier communication systems.

Selected when performing adaptive modulation in an Orthogonal Frequency Division Multiple Access (hereinafter referred to as OFDMA) system, which is a multiple access system based on Frequency Division Multiplex (hereinafter referred to as OFDM). The CQI (Channel Quality Indicator), which is uplink notification information, is notified of the different bands (group of subcarriers) by the difference value from the previous notification. A scheme has been proposed (J. Non Patent Literature 7).

Non-Patent Document 1: Takamura Yamako et al. “A Study on OFDM Mobile Radio Transmission System Using Adaptive Modulation”, Technical Report of IEICE, RCS 99—146, November 1999, p. 33 40

Non-Patent Document 2: Kishiyama Yoshihisa et al., “Downlink VSF—Results of Adaptive Modulation and Demodulation 'Channel Coding Throughput Performance in OFCDM Broadband Wireless Axes”, Technical Report of IEICE, RCS 2003— 25, May 2003 , P. 7— 14

Non Patent Literature 3: "Medium Access Control (MAC) Standard for cdma 200

0 Spread Spectrum Systems Release D, ARIB STD — T64 — C. S00

03-D vl. 0, Radio wave industry association, September 2005, p. 2-145-2-147,

Non-Patent Document 4: Tomoaki Yoshitoshi et al., "OFDM Adaptive Modulation with Multilevel Transmission Power Control for High-speed Data Transmission", Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No.

7, July 2001, p. 1141-1150

Non-patent document 5: Civilization by Maehara et al., "Examination of OFDM / TDD transmission scheme using subcarrier adaptive modulation," 2001 IEICE General Conference, B-5-100, March 2001, p. 4 98

Non-patent literature 6: Katsuyoshi Motoyoshi et al., "A study on the method of reducing CSI feedback information amount in OFDM FDD", 2005 IEICE Society Conference, B-5-28, September 2005, P. 428

Non-Patent Document 7: "Uplink CQI channel for OFDMA PHY", IEEE802. 16d 04 / 84rl, (US), Institute of Electrical and Electronics Engineers, April 28, 2004

Non-Patent Document 8: Tetsuro Yamamoto, “Introduction to Numerical Analysis,” Science, October 20, 1976, p.

70-81

Disclosure of the invention

Problem that invention tries to solve

However, in a multicarrier communication system in which information is carried on a plurality of subcarriers and communication is performed, in the case where adaptive modulation is performed on each subcarrier block consisting of at least one subcarrier, the reception state is set for each subcarrier block. Love from Need to be notified. However, when the information obtained from the reception status is notified as it is, as notification information (the number of bits necessary to represent the information obtained from the reception status)

Information on the number of bits of X (the number of subcarrier blocks) is required. For example, in the case of a system where the number of bits required to represent information obtained from the reception status is 8 and the number of subcarrier blocks is 768, 6144 bits are required for one notification information.

As described above, notification information with a large number of bits causes a large overhead for data communication, causing a problem of causing a decrease in system throughput. In addition, in the case of notifying these pieces of notification information using a control channel or the like used to exchange control information between communication devices, there is a problem that the bandwidth of a limited control channel is compressed. In addition, the time required for transmission and reception is long, leading to an increase in power consumption.

Further, according to Non-Patent Document 3, the level increase / decrease is determined based only on the magnitude of the measured value and the stored value, and when the notification information extends over a plurality of bits, only the magnitude of the measured value and the stored value is not A detailed comparison is required.

[0016] Furthermore, in Non-Patent Document 6, in the OFDM system, subcarriers are hierarchically hierarchically divided, and the difference between the average value of CSI in a group and the original CSI is repeatedly calculated over each layer, and A scheme has been proposed in which the average value of CSI obtained in a hierarchy is updated and notified in a different cycle for each hierarchy. In this method, since the amount of notification information fluctuates greatly each time, the configuration of a control channel for transmitting control information is complicated in a general system that transmits notification information as a part of control information. There was a problem of

The present invention has been made in view of such circumstances, and channel quality information obtained from the reception state of each channel is interpolated based on channel quality information of a part of channels. A notification that generates notification information that suppresses the amount of information and improves the accuracy of the channel quality information to be restored based on the difference by notifying the communication destination using the difference between the interpolation value and the channel quality information in each channel Information generation apparatus, communication apparatus, notification information generation method and notification information generation program

Means to solve the problem

(1) In order to solve the above-mentioned problems, a notification information generating device according to the present invention comprises a plurality of channels. A notification information generating apparatus that generates notification information based on channel quality information obtained from the state of reception of each channel in a communication scheme that performs communication using a communication channel. Based on the channel quality information, an interpolation value for interpolating the channel quality information in the selected other channel is calculated, and a difference value indicating the difference between the calculated interpolation value and the channel quality information in the other channel. And generation of notification information based on channel quality information in the two or more selected channels.

Thus, the notification information generation apparatus according to the present invention, when generating notification information for notifying channel quality information, selects two or more selected channels from a plurality of channels (two or more selected channels are selected. The notification information is generated separately for the channel and the other channels, and the channel quality information is generated as notification information as it is in the selection channel, and the other channel is interpolated based on the channel quality information in the selected channel. The difference value indicating the difference between the calculated interpolation value and the channel quality information of the other channel is generated as notification information. By setting the difference value to a smaller amount of information than notifying the channel quality information as it is, the amount of information of notification information can be suppressed, and an interpolation value interpolated based on channel quality information of a part of channels as a difference value. The accuracy of the channel quality information can be improved (maintained) by using the difference value between the and channel quality information of each channel.

(2) Further, in the notification information generating apparatus according to the present invention, the first group in which channel quality information in the plurality of channels is input, and two or more channels are selected from the plurality of channels, and The first group is divided into a second group including a force and another channel, and V based on channel quality information in the first group of channels, and the interpolation value in the second group of channels is calculated. Interpolator and channel quality information in each channel are generated as notification information for the first group of channels, and the difference value in each channel is generated for the second group of channels, and the generated difference value It is a feature of the present invention to provide a difference calculation unit that generates as notification information.

As described above, the interpolation unit is configured to set the plurality of channels into the first group and the first group according to a predetermined rule. The interpolation value in the second group of channels is calculated, and the difference calculation unit generates a difference value using the calculated interpolation value, and the channel quality information in the channel of the first group and the second group of It is possible to generate notification information based on the difference value in the channel. As a result, the amount of notification information can be suppressed and the accuracy of channel quality information can be improved (maintained).

(3) Further, in the notification information generation apparatus according to the present invention, the interpolation value and the notification information are input, and channel quality information in each channel of the notification information is input for the channels of the first group. The interpolation value is calculated as the restoration value, and the interpolation value is calculated based on the channel quality information of the first grain, which has been restored to the channel of the second group. The information processing apparatus further includes a restoration operation unit that restores channel quality information in each channel as restoration information based on the difference value indicated by the notification information.

As described above, the restoration operation unit restores channel quality information based on the interpolation value calculated by the interpolation unit and the notification information generated by the difference operation unit. Specifically, for the first group of channels, the notification information as it is is restored as channel quality information, and for the second group of channels, the interpolation value and the difference value indicated by the notification information are added. Restore channel quality information. By comparing the restoration information restored by the restoration operation unit with the channel quality information, the notification information generation apparatus can determine the accuracy of the notification information to be generated.

(4) In the notification information generation apparatus according to the present invention, the number of channels to be selected as the first group based on channel quality information in the plurality of channels. And selecting a channel selection method, and selecting the determined number of channels based on the determined selection method.

As described above, the interpolation unit determines the channel condition based on the channel quality information of each channel, and determines the number of channels in the first group and the method of selecting the channels based on the determination result. Force S can. As a result, the interpolation unit changes the channel of the first group according to the channel condition, and improves the accuracy (or maintenance) of the channel quality information from which the notification information has been restored. (5) In the notification information generation apparatus according to the present invention, the difference calculation unit calculates, for the channel of the second group, the difference between the interpolation value in each channel and the channel quality information, in advance. It is characterized in that a difference value indicating the calculated difference is generated using the set value.

As described above, the difference calculation unit holds the value of the difference value indicating the difference (difference) as a preset value, and selects the difference value indicating the difference from the held value, thereby as notification information. It becomes possible to reduce the amount of information to be notified.

(6) In the notification information generation apparatus according to the present invention, the interpolation unit may input the restoration information restored by the restoration calculation unit, and may be based on the channel quality information and the restoration information. It is characterized in that at least one of an interpolation method for calculating the interpolation value, a number of channels to be selected as the first group, and a selection method of channels to be selected as the first group is changed.

Thus, the interpolator compares the channel quality information obtained from the state of reception in each channel with the channel quality information (restoration information) restored using the notification information generated based on the interpolation value. · Reduce the difference between channel quality information and restoration information by changing at least one of a more appropriate interpolation method, the number of channels to be selected as a first group, or a channel selection method by evaluation. be able to. This can improve (maintain) the accuracy of notification information.

(7) The communication device according to the present invention is a communication device that performs communication using a plurality of channels, and the notification information generating device according to any one of (1) to (6) above, Notification Information A feature of the present invention is the provision of a transmission unit that transmits the notification information generated by the generating device to the communication partner.

Thus, the communication apparatus according to the present invention can suppress the amount of information of notification information and improve the accuracy of channel quality information by using the notification information generation apparatus described above. Can be maintained.

(8) The notification information generation method according to the present invention is a communication method in which communication is performed using a plurality of channels, and a notification for generating notification information based on channel quality information obtained from the reception state of each channel. A method of generating information, comprising two or more selected from the plurality of channels Based on channel quality information in the upper channel, an interpolation value for interpolating channel quality information in other channels not selected is calculated, and a difference indicating a difference between the calculated interpolation value and channel quality information in the other channel Notification information is generated based on the value and channel quality information in the selected one or more channels.

As described above, according to the notification information generation method of the present invention, when generating notification information for notifying channel quality information, a selected channel in which two or more are selected from a plurality of channels and the other channels are used. The channel quality information is divided and the interpolation value is calculated based on the channel quality information in the selected channel and the difference value indicating the difference between the calculated interpolation value and the channel quality information of the other channels. By combining with the channel to be notified, it is possible to make the amount of information smaller than that of notifying the channel quality information as it is, and it is possible to suppress the amount of information of the notification information, and the communication device which received the notification information In the above, the channel quality information is generated in the same procedure as the method of generating the difference value based on the channel quality information notified as notification information and the difference value. By original, it is possible to improve the accuracy of the channel quality information (maintained).

(9) The notification information generation program according to the present invention generates notification information based on channel quality information obtained from the reception state of each channel in a communication method in which communication is performed using a plurality of channels. A notification information generation program for causing a computer to execute a procedure, comprising: a procedure for inputting channel quality information in the plurality of channels; a first group in which two or more channels are selected from the plurality of channels; A step of dividing into a second group including other channels not selected as one group, and a step of calculating the interpolation value of the second group of channels based on channel quality information of the first group of channels; Generating the channel quality information in each channel as notification information for the first group of channels For the channel of the second group, it generates the difference value in each channel, to execute a procedure for generating the generated the difference value as the notification information, to the computer.

As described above, according to the notification information generation program of the present invention, when generating notification information for notifying channel quality information, it is possible to select two or more selected channels from a plurality of channels. The channel quality information is divided and notified to the channel and the other channels, and an interpolation value is calculated based on the channel quality information in the selected channel, and the calculated interpolation value and the channel quality information of the other channels. By combining with a channel for notifying a difference value indicating a difference, it is possible to make it possible to reduce the amount of information as compared to notifying channel quality information as it is, and to suppress the amount of information of notification information. In the communication device that received the message, the accuracy of the channel quality information is improved by restoring the channel quality information in the same procedure as the method of generating the difference value based on the channel quality information notified as notification information and the difference value ( Can be maintained.

Effect of the invention

According to the present invention, the channel quality information obtained from the reception state of each channel is interpolated based on the channel quality information of a part of the channel, and the difference between the interpolation value of each channel and the channel quality information in each channel is used. By reducing the amount of notification information and notifying the communication destination, it is possible to generate notification information that reduces the amount of information and improves the accuracy of the channel quality information to be restored based on the difference.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of the present invention will be described with reference to the drawings. Components and corresponding parts having the same configuration or function in the drawings are denoted by the same reference numerals, and the description thereof will be omitted.

In the following description of each embodiment, an OFDM system, which is a multi-carrier communication system, is assumed as a communication system, and a channel is a subcarrier block consisting of at least one subcarrier, or they are further divided by a fixed time length. Force to mean something S, not limited to this. For example, the present invention can be applied to an MC-CDMA (Multi Carrier-Code Division Multiple Access) system using a spreading technology. Also, the power described in regard to modulation parameter information in a plurality of frequency channels, the channel to which the present invention can be applied is not limited to the frequency channel, for example, a plurality of channels indicated by eigenmodes in SDMA (Space Division Multiple Access) or a combination thereof Communication system using a plurality of channels in a frame, such as a channel as The application of the present invention is possible in systems that may differ in quality. As used herein, a frame is a communication comprised of a plurality of slots identified by one or more time channels defined by a fixed time length and one or more frequency channels defined by a fixed frequency band. It is a unit.

Also, in each of the following embodiments, a communication system employing an FDD comprising a base station apparatus and a terminal apparatus, and assuming an adaptive modulation system of OFDM in downlink communication, it is assumed that uplink communication It is assumed that the system does not use OFDM and adaptive modulation in communication. Between the two communication devices, the terminal that notifies feedback information is the terminal equipment, and based on the feedback information that has been notified, the base station equipment that transmits / receives data by adaptive modulation, coding or scheduling. Do. Alternatively, the base station apparatus transmits the control information on the transmission data together with the transmission data by adaptive modulation / coding or scheduling of the transmission data, and the terminal apparatus receives the transmission information. One communication device may have both functions.

Channel quality information is information obtained from the reception state of each channel, and includes information indicating the propagation path state and information indicating the reception quality. The channel quality information includes information indicating a propagation path state measured by the communication apparatus that received the signal, or a parameter of adaptive modulation selected based on the information indicating the measured propagation path state. . Information indicating the propagation path status is measured by the communication device that has received the signal. Specifically, it is information that serves as a reference for determining modulation parameters in adaptive modulation, and includes CNR, CINR, and so on. Modulation parameters include a modulation scheme, a channel coding rate, and a combination of a modulation scheme and a channel coding rate (MCS: Modulation and Coding Scheme). When the modulation parameter is selected based on the information indicating the propagation path state measured by the communication device receiving the signal, the information indicating the propagation path state notified from the communication device receiving the signal from the communication device transmitting the signal is selected. If you choose based on, there are.

In each of the following embodiments, although modulation parameters (information on modulation parameters) or channel state estimation results are described as an example of channel quality information, the present invention is not limited thereto.

First Embodiment In the first embodiment, the communication destination is notified using modulation parameter information as channel quality information and using a difference between an interpolated value interpolated based on channel quality information of a part of channels and channel quality information of each channel. Reduces the amount of information, and generates notification information that maintains the accuracy of the channel quality information to be restored based on the difference.

Yes

FIG. 1 is a block diagram showing a configuration example of a base station apparatus 100 according to the first embodiment of the present invention. FIG. 2 is a block diagram showing a configuration example of the terminal device 200 according to the first embodiment of the present invention. In the first embodiment, the base station apparatus 100 notifies of information on modulation parameters used for adaptive modulation of downlink transmission data as downlink notification information, and the terminal apparatus 200 notifies of uplink. An example in the case of notifying information on modulation parameters for next downlink transmission data as information is shown.

The base station apparatus 100 includes an error correction coding unit 101, a modulation unit 102, a multiplex unit 103, an inverse Fourier transform unit 104, a wireless transmission unit (transmission unit) 105, antenna units 106 and 107, and a wireless reception unit. (Receiving Unit) 108, a demultiplexing unit 109, a demodulation unit 110, an error correction decoding unit 111, a notification information restoring unit 300, and an adaptive modulation control unit 112.

Terminal apparatus 200 includes antenna units 201 and 214, wireless reception unit (reception unit) 202, Fourier transform unit 203, demultiplexing unit 204, propagation path estimation unit 205, modulation parameter selection unit 206, notification information generation apparatus 400, notification information recovery unit 300, adaptive demodulation control unit 207, demodulation unit 208, error correction decoding unit 209, error correction coding unit 210, modulation unit 211, multiplex unit 212, and wireless transmission unit (transmission unit) And 213.

First, the downlink transmission procedure in the base station apparatus of FIG. 1 will be described. Error correction coding section 101 receives the downlink transmission data and the adaptive modulation control information output from adaptive modulation control section 112, and performs error correction coding on the downlink transmission data based on the received adaptive modulation control information. , Output an encoded data sequence. The modulation unit 102 receives the coded data sequence output from the error correction coding unit 101 and the adaptive modulation control information output from the adaptive modulation control unit 112, and generates coded data based on the input adaptive modulation control information. Modulate the sequence and output a modulated symbol sequence.

Multiplexing section 103 receives the modulation symbol sequence output from modulation section 102, and demultiplexing. Uplink notification information (notification information notified from the terminal device 200) and pilot signals separated by the Plettuce unit 109 and a pilot signal are input, these are multiplexed, and an OFDM frequency signal is output. Here, the pilot signal is a known signal for terminal 200 to estimate the channel state. It is preferable that the base station apparatus 100 accumulates pilot signals generated in advance in a memory, and input the pilot signals accumulated in the memory to the multi-pretus unit 103. Alternatively, the base station apparatus 100 may be configured to generate pilot signals as needed without storing them in a memory.

The inverse Fourier transform unit 104 receives the OFDM frequency signal output from the multi-pretus unit 103, frequency-time transforms (inverse Fourier transform) the same, and outputs an OFDM time signal. The wireless transmission unit 105 receives the OFDM time signal output from the inverse Fourier transform unit 104, adds a guard period thereto, upconverts it to digital / analog conversion and radio frequency, and converts it to a wireless signal, and the antenna unit Send via 106.

Next, the downlink reception procedure in the terminal apparatus 200 of FIG. 2 will be described. The wireless reception unit 202 receives a downlink radio signal via the antenna unit 201, downconverts from the radio frequency and performs analog-to-digital conversion, removes the guard period, and outputs an OFDM time signal. The Fourier transform unit 203 receives the OFDM time signal output from the wireless reception unit 202, time-frequency transforms it (Fourier transform), and outputs an OFDM frequency signal.

Demultiplexing section 204 receives the OFDM frequency signal output from Fourier transform section 203, and separates the received OFDM frequency signal into a downlink received data signal, downlink notification information, and a pilot signal, Output each. The propagation path estimation unit 205 receives the pilot signal output from the demultiplexer 204, estimates a propagation path condition from the input pilot signal, and outputs a propagation path condition estimation result.

When channel estimation is performed using a downlink received data signal, instead of the pilot signal, the downlink reception data signal, the demodulation result of the downlink reception data signal or the error correction decoding result is channel estimation. Input to the department. In this case, it is not necessary to perform pilot signal multiplexing processing in the multiplexor section 103 in the base station apparatus 100 and separation processing of pilot signals in the demultiplexing section 204 in the terminal apparatus 200. Also, the pilot signal When performing propagation channel estimation using both of the received data signal, in addition to the pilot signal, the downlink reception data signal, the demodulation result of the downlink reception data signal or the error correction decoding result is also input to the channel estimation unit. Ru. The present invention can also be applied to these configurations.

The modulation parameter selection unit 206 receives the channel state estimation result output from the propagation channel estimation unit 205, and the next downlink modulation parameter for each subcarrier block is input based on the input channel state estimation result. Is selected, and information on the selected modulation parameter (modulation parameter information) is output. The modulation parameter selection unit 206 selects a modulation parameter by applying the channel state estimation result to a predetermined correspondence relationship between the modulation parameter and the channel state. For example, the modulation parameter and the corresponding channel state range are held as a table, and the selected modulation parameter can be determined by comparing the table with the channel state estimation result.

The notification information generation apparatus 400 receives the modulation parameter output from the modulation parameter selection unit 206, generates uplink notification information based on the input modulation parameter, and outputs the uplink notification information. The processing in the notification information generating apparatus 400 will be described later with reference to FIGS. 3 and 4.

Notification information restoration section 300 receives the downlink notification information output from demultiplexing section 204, and restores and outputs information on modulation parameters from the input downlink notification information. The processing in the notification information restoration unit 300 will be described later using FIG. 5 and FIG.

The adaptive demodulation control unit 207 receives information (modulation parameter information) on the restored modulation parameter output from the notification information restoring unit 300, and performs demodulation processing based on the information on the input modulation parameter. It generates and outputs adaptive demodulation control information that controls error correction decoding processing.

Demodulation section 208 receives the downlink received data signal output from demultiplexing section 204 and the adaptive demodulation control information output from adaptive demodulation control section 207, and based on the received adaptive demodulation control information. It demodulates the downlink received data signal and outputs a demodulated data sequence.

The error correction decoding unit 209 performs adaptive demodulation and correction on the demodulated data sequence output from the demodulation unit 208. The adaptive demodulation control information output from the tone control unit 207 is input, error correction decoding is performed on the demodulated data sequence based on the input adaptive demodulation control information, and downlink reception data is output. It should be noted that, as pre-processing for demodulation, a configuration for performing channel compensation processing using the channel state estimation result estimated by channel estimation section 205 or a configuration for referring to the channel state estimation result at the time of error correction decoding Well ,.

Next, the uplink transmission procedure in the terminal device 200 of FIG. 2 will be described. The error correction coding unit 210 receives uplink transmission data, performs error correction coding on the uplink transmission data at a predetermined channel coding rate, and outputs a coded data sequence. The modulation unit 211 receives the coded data sequence output from the error correction coding unit 210, modulates the input coded data system 歹 IJ according to a predetermined modulation scheme, and outputs a modulation symbol sequence.

The multiplexor unit 212 receives the modulation symbol sequence output from the modulation unit 211 and the uplink notification information output from the notification information generation apparatus 400, and receives the modulation symbol system 歹 IJ and the uplink notification information. And transmit the transmission signal. The wireless transmission unit 213 receives the transmission signal output from the multi-plaitas unit 212, converts the input transmission signal into a digital signal by analog conversion and radio frequency conversion and converts it into a wireless signal, and transmits the signal via the antenna unit 214. Send.

Next, the uplink reception procedure in base station apparatus 100 in FIG. 1 will be described. The radio reception unit 108 receives an uplink radio signal via the antenna unit 107, performs radio frequency power conversion, analog-to-digital conversion, and outputs a reception signal.

Demultiplexing section 109 receives the reception signal output from radio reception section 108, separates the input reception signal into an uplink reception data signal and uplink notification information, and outputs them. In addition, the pilot signal is multiplexed in advance by multiplex section 212 in terminal apparatus 200, the pilot signal is separated by demultiplex section 109 in base station apparatus 100, and uplink reception is performed using the separated pilot signal. The channel compensation may be performed on the data signal and the uplink notification information.

Demodulation section 110 receives the uplink reception data signal output from demultiplexing section 109, demodulates the input uplink reception data signal according to a predetermined modulation scheme, and outputs a demodulation data sequence. . The error correction decoding unit 1 1 1 outputs the signal output from the demodulation unit 1 10 A tone data sequence is input, the input demodulated data sequence is error correction decoded at a predetermined channel coding rate, and uplink reception data is output.

The notification information restoration unit 300 receives the uplink notification information output from the demultiplexer 109, and restores and outputs information on modulation parameters from the input uplink notification information. The process in the notification information restoring unit 300 will be described later with reference to FIG. The adaptive modulation control unit 112 receives information on the modulation parameter output from the notification information restoring unit 300, and generates and outputs an adaptive modulation control signal for controlling modulation processing and error correction coding processing.

FIG. 3 shows an example of a block diagram of notification information generating apparatus 400 in terminal apparatus 200 of FIG. The notification information generation device 400 includes an interpolation unit 401, a difference calculation unit 402, and a restoration calculation unit (restoration unit) 403. Notification information generating apparatus 400 divides a plurality of subcarrier blocks into two groups (first group and second group), and uses modulation parameters (an example of channel quality information) of subcarrier blocks belonging to the first group. The interpolation value to interpolate (predict) the modulation parameter of the subcarrier block of the second node is calculated, and the notification information is calculated using the difference value indicating the difference between the calculated interpolation value and the modulation parameter actually selected. Generate

Each component of notification information generating apparatus 400 combines information on the selected modulation parameter with a combination of subcarrier block number (channel number) for identifying subcarrier blocks and the modulation parameter for subcarrier block number. It is assumed that the processing is carried out while obtaining the correspondences between subcarrier blocks and modulation parameters by subcarrier block numbers. Also, even for other pieces of information, correspondence between subcarrier blocks and each piece of information can be made correspondence by subcarrier block numbers.

Interpolation section 401 receives modulation parameters in a plurality of subcarrier blocks, divides the plurality of subcarrier blocks into a first group (first channel group) and a second group (second channel group), and An interpolation value for predicting (interpolating) modulation parameters in each subcarrier block belonging to the second group is calculated using modulation parameters (an example of channel quality information) in subcarrier blocks belonging to one group, and It is output to the restoration operation unit 403. The first group uses a plurality of channels according to predetermined rules Among the modulation parameters which are the selected (two or more) subcarrier blocks and which are input to the notification information generating apparatus 400, the subcarrier blocks to which the modulation parameters are notified as notification information belong. The second group is another subcarrier block which is not selected as the first group, and based on a predetermined interpolation method, channel quality information from modulation parameters in each subcarrier block of the first group. Subcarrier block to be interpolated belongs. Specifically, the following operation is performed.

Interpolation section 401 receives the modulation parameter for each subcarrier block selected in modulation parameter selection section 206 in FIG. 2, and extracts (selects) the modulation parameter of the first group from among them. An interpolation value in each subcarrier block of the second group is calculated and output from modulation parameters in each subcarrier block of the first group extracted based on a predetermined interpolation method. That is, the interpolation unit 401 calculates an interpolation value for each subcarrier block belonging to the second group based on a predetermined interpolation method using modulation parameters in each subcarrier block belonging to the first group.

The selection method (extraction method) of the subcarrier block belonging to the first group is determined in advance between the base station apparatus 100 and the terminal apparatus 200 or not. It may be determined in the interpolator 401 so that the interpolation result becomes good according to the size of fluctuation of the selected modulation parameter between subcarrier blocks and the speed of fluctuation in the frequency direction. For example, the interpolator 401 controls the number of subcarrier blocks in the first group to increase as the variation between subcarrier blocks of the selected modulation parameter increases or as the rate of variation in the frequency direction increases. It is preferable to do. As described above, the accuracy of channel quality information restored from notification information can be improved (maintained) by changing the number of channels in the first group and the selection method according to channel conditions. This makes it possible to calculate an interpolation value closer to the actual measured channel quality information.

Specifically, the following operation can be considered as an example. The modulation parameter selected for each of a plurality of subcarrier blocks included in the communication unit is regarded as a function of frequency (function of subcarrier block number), and the fluctuation period of the function (maximum value or minimum value) The interpolation unit 401 determines an interval for selecting the first group sub-carrier block so as to be half or less of the average of the appearance cycle of (1). Further, for each shorter frequency range, the interpolation unit 401 may determine the interval for selecting the subcarrier block of the first group in the same manner as described above according to the fluctuation cycle in that range. Furthermore, subcarrier blocks taking the above-mentioned maximum value and minimum value may be selected as subcarrier blocks of the first group.

As another example, the following operation may be considered. Here, “between adjacent subcarrier blocks” (also referred to as “between adjacent channels or between selected channels”) refers to two adjacent subcarriers (close in frequency band) among the selected first group subcarrier blocks. Indicate between blocks. Interpolation section 401 selects a subcarrier block of the first group according to a predetermined rule, compares modulation parameters in the selected subcarrier block among adjacent subcarrier blocks, and the comparison result has a predetermined size. When the number of adjacent subcarrier blocks exceeds a predetermined number, one or more subcarrier blocks existing between adjacent subcarrier blocks are additionally selected as a first group.

Interpolation unit 401 generates grouping information specifying a selection method of subcarrier blocks belonging to the first group, and notifies difference operation unit 402 and restoration operation unit 403 of the grouping information. The grouping information includes information such as whether the selection is made according to a predetermined rule, or whether a subcarrier block is selected additionally, or an interval (selection interval, extraction interval) for selecting subcarrier blocks. Be

Although it is preferable that the subcarrier blocks of the first group are arranged at equal intervals (in the frequency direction), the present invention is not limited to this. In the case of adaptively determining the subcarrier block of the first group, it is necessary to notify the determination result together with the notification information to the communication apparatus of the other party (here, the base station apparatus 100). If the interval is set adaptively, it is sufficient to notify only the information of the determined interval together with the notification information. For example, when there is an agreement between the terminal device 200 and the base station device 100 to notify the interval for selecting a subcarrier block, the interpolation unit 401 sets the interval (natural number n) of the subcarrier block to be selected. Grouping Information will be generated and notified as information. In addition, when selecting a subcarrier block belonging to the first Gnolae according to a predetermined rule, the interpolation unit 401 performs grouping information. It is not necessary to notify the information to the other components in the notification information generating apparatus 400.

Further, the interpolation method employs a method of calculating by an arithmetic expression using modulation parameters in subcarrier blocks of the first group. For example, (1) linear interpolation for obtaining interpolation values of subcarrier blocks of a second group existing between adjacent subcarrier blocks (adjacent subcarrier blocks) of two adjacent first G 2) Connect the first N groups of subcarrier blocks using a curve of the (N-1) th degree polynomial, and use polynomial interpolation to obtain interpolation values of the second group of subcarrier blocks existing between them, (3 Similarly, spline interpolation using a spline curve can be applied. Although the specific calculation method of the interpolation value is omitted, it is described in Non-Patent Document 8. Further, the above-mentioned interpolation method is an example, and other interpolation methods may be used. Although the case of interpolating between adjacent subcarrier blocks has been described above, the subcarrier blocks belonging to the second group to be interpolated are not limited to between the adjacent subcarrier blocks, and the subcarriers of the first group are not limited. It is also possible to calculate interpolation values using subcarriers for subcarrier blocks belonging to the second group in which there is only one block. In the case of extrapolation, it is possible to use a method such as calculation using an arithmetic expression used between adjacent adjacent subcarrier blocks.

Thus, the interpolation unit 401 creates an interpolation function using modulation parameters in the selected first group of subcarrier blocks, and calculates the interpolation value of the second loop based on the created interpolation function. It will be done. Furthermore, the interpolation unit 401 compares the selected modulation parameter input from the modulation parameter selection unit 206 with the restored modulation parameter input from the restoration operation unit 403 with (restoration information) to evaluate the subcarrier. By changing the block selection interval (number of channels to be selected), selection method, or interpolation method, more appropriate notification information is generated so that the difference between the selected modulation parameter and the restored modulation parameter becomes smaller. Implement feedback processing to For example, the interpolation unit 401! /, Various interpolation intervals and selection methods! /, Generate interpolation values, feed back restoration information based on each, select modulation parameters and respective restoration information The information is compared, the difference is smaller, and the amount of notification information (the number of bits of notification information) is also smaller. Select the selection interval, the interpolation method, or both. When the interpolation method is adaptively selected, the interpolation unit 401 further generates interpolation method information specifying the interpolation method, and notifies the difference calculation unit 402 of the information.

Differential operation section 402 receives modulation parameters in a plurality of subcarrier blocks, interpolation values in each subcarrier block belonging to the second loop, and grouping information as necessary, and belongs to a second group. For each subcarrier block, a difference value indicating the difference between the modulation parameter and the interpolation value is calculated, and the modulation parameter in each subcarrier block belonging to the first group and the difference value in each subcarrier block belonging to the second group Generate notification information based on. The difference calculation unit 402 is premised on obtaining a combination of the subcarrier block number and the interpolation value corresponding to the subcarrier block number as the interpolation value. Specifically, the following operation is performed.

The difference operation unit 402 is a modulation parameter for each subcarrier block selected in the modulation parameter selection unit 206 in FIG. 2, and an interpolation function in each subcarrier block of the second group calculated by the interpolation unit 401, When the first group of subcarrier blocks is determined by the interpolation unit 401, the determined subcarrier block information of the first group (the grouping information generated by the interpolation unit 401) and the interpolation method by the interpolation unit 401 are further determined. When deciding, input information (interpolation method information) specifying the determined interpolation method. The difference calculation unit 402 outputs the selected modulation parameter as notification information for each subcarrier block as it is for each subcarrier block of the first group, and the selected modulation parameter is selected for each subcarrier block of the second group. The difference value between the modulation parameter and the interpolation value is determined, and the difference value is output as notification information for each subcarrier block. The difference value is preferably selected from values that can be represented by a smaller number of bits than the number of bits required to represent modulation parameters, in order to suppress the amount of information of notification information. For example, a difference value is obtained by rounding the difference to a range that can be expressed in 2 bits. Further, the notification information generation apparatus 400 holds several candidate values as a notification information based on the difference value as a table in advance (for example, in the difference calculation unit 402), and the difference calculation unit 402 selects from the table. You may

Difference operation unit 402 generates notification information based on the modulation parameter in the subcarrier block of the first group and the difference value in the subcarrier block of the second group. When the grouping information, the interpolation method information, or both are notified from the force interpolation unit 401, the information is also included in the notification information to be notified to the base station apparatus 100.

The restoration operation unit 403 is configured to receive the notification information generated by the difference operation unit 402, the interpolation value in each subcarrier block of the second group calculated by the interpolation unit 401, and the sub-group of the first group by the interpolation unit 401. When determining a carrier block, subcarrier block information (grouping information generated by the interpolator 401) of the determined first group is input. The restoration calculation unit 403 outputs, for each subcarrier block of the first group, the notification information as it is as a restored modulation parameter (restored channel quality information) for each subcarrier block, and for each subcarrier of the second group. For the block, the notification information and the interpolation value are added, and the added value is output as a reconstructed modulation parameter in each subcarrier block. The restored modulation parameter (restoration information) restored by the restoration calculation unit 403 is output to the interpolation unit 401. The restoration information enables the notification information generation device to determine the accuracy (the accuracy to be restored) of the generated notification information.

Next, an operation of generating notification information will be described with reference to FIG. FIG. 4 is a flowchart showing an example of an operation of generating notification information in the present embodiment. In the flow chart, the subcarrier block is denoted by "SB", and the s-th subcarrier block is denoted by "SB (s)". The same applies to the subsequent flowcharts.

Interpolation section 401 and difference calculation section 402 receive the selected modulation parameter of each subcarrier block (S11). First, the interpolation unit 401 selects a subcarrier block belonging to the first group (S12). Next, the interpolation unit 401 calculates and outputs the interpolation value in each subcarrier block of the second group using the modulation parameter of each subcarrier block in the first group (S 13). The difference calculation unit 402 determines whether the sth subcarrier block is the first group (S15), and for the first group subcarrier block (Yes in S15), the modulation parameter related to the subcarrier block is determined. Is output as notification information as it is (S16). For the second group of subcarrier blocks (No at S15), the modulation parameters for the subcarrier blocks and the input from the interpolator 401 A difference value with the interpolation value related to the subcarrier block is calculated (S17), and the difference value or a value selected from the difference value is output as notification information (S18). In FIG. 4, the differential operation unit 402 repeats the process for each subcarrier block in order corresponding to each of a plurality of subcarrier blocks included in the communication unit (loop 1 from S14 to S19). .

FIG. 5 shows an example of a block diagram of the notification information restoring unit 300 in the present embodiment. The notification information restoration unit 300 includes an interpolation unit 301 and a restoration operation unit 302. Notification information restoration section 300 receives uplink notification information in base station apparatus 100 and downlink notification information in terminal apparatus 200, and uses modulation parameters in subcarrier blocks belonging to the first group to be notified as notification information. The modulation parameter is restored from the difference value in the subcarrier block belonging to the second group. The base station apparatus 100 and the terminal apparatus 200 include the notification information restoring unit 300 having the same configuration. By providing the notification information restoration unit 300 (the notification information restoration device), it is possible to restore the notification information generated in the notification information generation device 400 and acquire channel quality information (modulation parameter).

Interpolation section 301 receives the notification information, and based on the notification information on each subcarrier block of the first group among them, that is, the modulation parameter, each subcarrier of the second group is determined based on the interpolation method determined in advance. Calculate the interpolation value in the block. This interpolation value calculation method uses the same method as the interpolation unit 401 in the notification information generation apparatus 400. As a result, the interpolation value calculated by the interpolation unit 301 is the same as that of the interpolation unit 401. Among the plurality of subcarrier blocks, subcarrier blocks belonging to the first group are selected in the same manner as the interpolation unit 401 of the notification information generation apparatus 400. In addition, when the grouping information is included in the notification information, the interpolation unit 301 selects subcarrier blocks belonging to the first group by a method defined in the grouping information in addition to a predetermined rule. Further, when the notification information includes interpolation method information, the interpolation unit 301 calculates an interpolation value by a method defined in the interpolation method information in addition to a predetermined interpolation method.

The restoration calculation unit 302 receives notification information and the interpolation value in each subcarrier block of the second group calculated by the interpolation unit 301, and the notification information is input for each subcarrier block of the first group. Recovered modulation in each subcarrier block as it is For each subcarrier block of the second group, the notification information and the interpolation value are added, and the added value is output as a reconstructed modulation parameter for each subcarrier block.

Next, the details of the operation in which the notification information restoring unit 300 restores the notification information will be described using FIG. FIG. 6 is a flowchart showing an example of an operation of restoring notification information in the present embodiment. The interpolation unit 301 and the restoration operation unit 302 receive notification information of each subcarrier block (S21). First, the interpolation unit 301 selects subcarrier blocks belonging to the first group (S22). Next, the interpolation unit 301 calculates and outputs the interpolation value in each subcarrier block of the second group using notification information of each subcarrier block of the first group in the notification information, that is, the modulation parameter (S23). ). The restoration operation unit 302 determines whether the subcarrier block is the first gonolap (S25), and for the first group subcarrier block (Yes in S25), the notification information on the subcarrier block is restored as it is. The modulation parameter is output (S26). For the second group of subcarrier blocks (No in S25), an addition value of notification information on the subcarrier block and an interpolation value on the subcarrier block input from the interpolation unit 301 is calculated (S27), and the addition value is calculated. It is output as the restored modulation parameter (S28). In FIG. 6, the restoration calculation unit 302 sequentially repeats the processing for each subcarrier block in response to each of the plurality of subcarrier blocks included in the communication unit (S24, power, etc. 1) shows an example.

In FIG. 7, the selected modulation parameter which is the input information of the notification information generating apparatus 400 in the present embodiment, and the calculation result of the interpolation value using linear interpolation by the interpolation unit 401, the notification information generating apparatus 400 An example of notification information generation results and restored modulation parameters is shown. The selected modulation parameter is selected by the modulation parameter selection unit 206 and output to the notification information generator 400.

In FIG. 7, base station apparatus 100 and terminal apparatus 200 use MCS (Modulation and Channel Coding Scheme) consisting of a combination of a modulation scheme and a channel coding rate with 16 subcarrier blocks as the modulation parameter. The example used is shown. There are 16 types (4 bits of information) of 0 to 15 for MCS. Also, as notification information, For one group of subcarrier blocks! /, The MCS is directly expressed by 4 bits, and for the second group of subcarrier blocks, 2 bits of 2's complement (one 2, -1, ± 0, and An example in the case of + 1) is shown. Further, an example is shown in which the first group subcarrier pattern has four subcarrier block numbers 1, 6, 11 and 16 and the second group subcarrier block has 12 other than that. That is, FIG. 7 shows an example in which the interpolator 401 selects a subcarrier block of the first group every five subcarrier blocks (a subcarrier block selection interval is 5).

In the example of FIG. 7, the interpolation unit 401 of the notification information generation apparatus 400 selects the modulation parameter “6” selected in each of the first, sixth, eleventh, and sixteenth sub-carrier blocks of the first group, Using “6”, “11” and “6”, linear interpolation is performed by connecting straight lines between the two to calculate interpolation values in each subcarrier block of the second group. For example, the interpolation values in the 15th subcarrier block belonging to the second group are selected modulation parameter "11" of the 11th subcarrier block and selected modulation parameter "6" of the 16th subcarrier block. Connect with a straight line and calculate "7" (= 11 + (6-11) X (15-11) / (16-11)). Thus, the interpolation value in the Xth (X is 12 to 15) subcarrier block belonging to the second group existing between the 11th and 16th is (11 + (6-11) X (X- 11) Calculated by the formula of (16-11). The same calculation formula is used to calculate an interpolation value for subcarriers belonging to the second group existing among other adjacent subcarrier blocks.

The difference calculation unit 402 uses the selected modulation parameter as notification information as it is for each subcarrier block of the first group, and calculates the selected modulation parameter and the interpolation unit 401 for each subcarrier block of the second group. Calculate the difference value with the interpolated value and use it as notification information. For example, since the selected modulation parameter in the 15th subcarrier block is “8” and the interpolation value is “7”, the difference value is “+1”, and the notification information is “+1”. Be done. For example, as in the 12th subcarrier block, the selected modulation parameter is “12” and the interpolation value is “10”, so that the difference value is “+2”, and the notification information of the second group is obtained. The value set as a candidate (candidate value, in the example of Fig. 7, 2 bits of 2's complement in the example shown in Fig. 7) Cases can happen. This In such a case, select from among the values set as candidates for notification information, the one closest to the difference value, or the largest one whose sum with the interpolation value does not exceed the selected modulation parameter, etc. It is information.

The difference calculation unit 402 may hold values other than the above as candidate values of notification information! /. Further, candidate values are not limited to candidate values of difference values, and may be absolute values of difference values or non-difference values representing a modulation parameter. For example, the candidate value of the difference value accompanied by the sign may be notified by combining the absolute value or the non-difference value of the difference value! / ,.

[0091] For each subcarrier block in the first group, restoration operation unit 403 outputs the notification information output from difference operation unit 402 as it is as a restored modulation parameter in each subcarrier block, and For each subcarrier block, the notification information and the interpolation value output from the interpolation unit 401 are added, and the addition value is output as a reconstructed modulation parameter in each subcarrier block. For example, since the 11th subcarrier block is the first group, the notification information "11" is output as it is as a reconstructed modulation parameter, and the 12th subcarrier is the second group, and the notification information "+1" is output. And interpolation value "10" are added to output "11" as a restored modulation parameter.

[0092] FIG. 8 is a graph showing selected modulation parameters, direct spring for interpolation (interpolation line), interpolation values, notification information and restored modulation parameters shown in the example of FIG. 7 It is. The horizontal axis is a subcarrier block number, and the vertical axis is a modulation parameter. Black circles indicate selected modulation parameters of each subcarrier block input to the notification information generation device, alternate long and short dashed lines indicate interpolation straight lines, open diamonds indicate interpolation values, and open triangles are shown. Indicates the reconstructed modulation parameters. In addition, numerical values shown near triangles or diamonds indicate actual notification information values. The arrow of the dotted line connecting the open rhombus and the open triangle represents the situation where the interpolation value is restored by the notification information, where the open triangle and the black circle overlap. Indicates that the selected modulation parameter matches the restored modulation parameter! /.

In FIG. 9, the selected modulation parameter which is the input information of the notification information generating apparatus 400 in the present embodiment, and the result of calculation of the interpolation value using spline interpolation by the interpolation unit 401, the notification information generating apparatus 400 , Notification information generation result and restored modulation parameters Another example of

In FIG. 9, under the same conditions as the subcarrier block configuration of the example of FIG. 7, the selected modulation parameter, and the expression of notification information, an example of the case where the interpolation value is calculated using the spline curve in the interpolation unit 401 Show me! A method of calculating an interpolation value using a spline curve is omitted here (see Non-Patent Document 8).

Details of the procedure of notification information generation in FIG. 9 are basically the same as the example in FIG. The different part is a part that uses spline interpolation with a spline curve instead of linear interpolation with a straight line in calculating the interpolation value in the interpolation unit 401.

Further, FIG. 10 is a graph showing the selected modulation parameters, spline curves for interpolation (spline interpolation curves), interpolation values, notification information and restored modulation parameters shown in the example of FIG. It is shown. The horizontal axis is subcarrier block number, the vertical axis is modulation parameter, and symbols in the figure are the same as in FIG. In FIG. 10, there are interpolation values that do not match the values of the spline interpolation curve in each subcarrier block of the second group, but this is a value that the modulation parameter can actually take. This is because a value obtained by rounding the spline interpolation value to the nearest integer value is calculated as the interpolation value so as to be matched with the integer value of 15. It should be noted that as a method of this correction, a method of rounding to the maximum integer value, which does not exceed the value of spline interpolation, may be used.

When a correction method is selected from a plurality of methods, an interpolation unit 401 generates interpolation values according to various selection intervals and interpolation methods, feeds back restoration information based on each, and is selected. It is preferable to compare the modulation parameters with the respective restoration information and select an interpolation method that reduces the difference. For example, when the number of bits used for notification information and the number of subcarriers in the first group are considered to be the same, the interpolation method by linear interpolation illustrated in FIG. 7 is compared with the interpolation method by spline interpolation illustrated in FIG. Then, the difference between each selected modulation parameter and the restored parameter is smaller! /, It is preferable to select an interpolation method by spline interpolation.

As described above, according to the present embodiment, when the modulation parameter is notified to the communication destination as channel quality information, in the first group, the modulation parameter is directly used as the notification information, and in the second group, the modulation in the first group is performed. Interpolated value and modulation parameter determined from parameters By notifying the difference value with the data as notification information, it is possible to improve (maintain) the accuracy of the channel quality information to be restored while reducing the amount of notification information.

Although FIG. 3 illustrates the configuration example in which the notification information generation device 400 includes the restoration calculation unit 403, the notification information generation apparatus 400 may not include the restoration calculation unit 403 as illustrated in FIG. . FIG. 12 is a diagram showing another example of functional blocks of the notification information generating apparatus in the terminal apparatus of FIG. When the interpolation unit 401 performs grouping according to a predetermined rule, and calculates an interpolation value according to a predetermined interpolation method, the grouping rule and the interpolation method are again performed using the restored modulation parameters. Since it is not necessary to perform feedback processing on interpolation to change the interpolation value to a more appropriate value, the restoration operation unit 403 is not required.

Second Embodiment

In the second embodiment, communication is performed using a channel state estimation result as channel quality information, and using a difference between an interpolated value interpolated based on channel quality information of a part of channels and channel quality information of each channel. In addition to reducing the amount of information by notifying earlier, it generates notification information that maintains the accuracy of the channel quality information to be restored based on the difference.

FIG. 12 is a block diagram showing a configuration example of a base station apparatus 190 according to the second embodiment of the present invention. Further, FIG. 13 is a block diagram showing a configuration example of a terminal device 290 in the second embodiment according to the present invention. In the second embodiment, information on a modulation parameter used for adaptive modulation of downlink transmission data is notified as downlink notification information, and a channel state estimated from a downlink reception signal as uplink notification information. An example of notifying is shown.

In base station apparatus 190 shown in FIG. 12, modulation parameter selection section 191 and notification information generation apparatus 500 are added to base station apparatus 100 shown in FIG. 1, and notification information restoration section 390 serves as uplink notification information. The difference is that the channel state estimation result is restored. Other components are the same as in FIG.

Modulation parameter selection section 191 is a modulation parameter selection section in terminal apparatus 200 shown in FIG.

It can be realized with the same circuit configuration as the circuit 206. The notification information restoration unit 390 is shown in FIG. Although the amount of information input to and output from the knowledge information restoration unit 300 is different, it can be realized by a circuit that performs the same process. The notification information generation apparatus 500 receives the modulation parameter output from the modulation parameter selection unit 191, and generates and outputs downlink notification information based on the input modulation parameter. The processing in the notification information generating apparatus 500 will be described later with reference to FIG.

The terminal device 290 shown in FIG. 13 has substantially the same configuration as the terminal device 200 shown in FIG. 2. The terminal device 290 has a modulation parameter between the channel estimation unit 205 and the notification information generation device 490. The notification information generation device 490 uses the channel state estimation result output from the channel estimation unit 205 as an input signal, and the notification related to the channel state estimation result as uplink notification information. The point of generating information is different.

The downlink transmission procedure in base station apparatus 190 in FIG. 12 is the same as the downlink transmission procedure in base station apparatus 100 in FIG.

Next, the downlink reception procedure in the terminal device 290 of FIG. 13 will be described. The operations of the radio reception unit 202, the Fourier transform unit 203, the demultiplexing unit 204, the propagation path estimation unit 205, the adaptive demodulation control unit 207, the demodulation unit 208, the error correction decoding unit 209, and the notification information restoration unit 300 It is the same as the downlink reception procedure in the terminal device 200 of FIG.

The notification information generation unit 490 receives the channel state estimation result output from the channel estimation unit 205, and generates and outputs uplink notification information based on the input channel state estimation result. The processing in the notification information generation apparatus 490 will be described later with reference to FIG. Further, the uplink transmission procedure in the terminal apparatus 290 in FIG. 13 is the same as the uplink transmission procedure in the terminal apparatus 200 in FIG.

Next, the uplink reception procedure in base station apparatus 190 in FIG. 12 will be described. The operations of the radio reception unit 108, the demultiplexing unit 109, the demodulation unit 110, the error correction decoding unit 111, and the adaptive modulation control unit 112 are the same as the uplink reception procedure in the base station apparatus 100 of FIG. The notification information recovery unit 390 receives uplink link notification information output from the demultiplexer 204, and restores and outputs information on the downlink channel state estimation result also for the input uplink notification information. The process in the notification information restoring unit 390 will be described later with reference to FIG. Modulation parameter selection section 191 receives the downlink channel state estimation result output from notification information recovery section 390, and based on the input channel state estimation result, performs the next downlink for each subcarrier block. Select the link modulation parameter and output the selected modulation parameter. The selection of the modulation parameter is performed by applying the channel state estimation result to the predetermined correspondence relationship between the modulation parameter and the channel state. For example, the modulation parameter and the corresponding channel state range are held as a table, and the modulation parameter to be selected can be determined by comparing the table with the channel state estimation result.

Notification information generation apparatus 500 receives the information on the modulation parameter output from modulation parameter selection section 191, generates downlink link notification information based on the information on the input modulation parameter, and outputs the downlink link notification information. Information on modulation parameters is restored and output based on downlink notification information. Further, the processing in the notification information generating apparatus 500 will be described later with reference to FIG.

FIG. 14 shows a block diagram of the notification information generation device 490 in the terminal device 290 of FIG. The notification information generation unit 490 uses a channel state estimation result as an example of channel quality information, which is different from the notification information generation unit 400 shown in FIG. 3 Basically, the notification information generation unit 400 shown in FIG. And perform similar operations. In the present embodiment, among the channel state estimation results input to notification information generating apparatus 490, the first group reports a plurality of (two or more) subcarrier blocks that directly notify the channel state estimation results as notification information. It is. The second group is a subcarrier block which does not belong to the first group, that is, a subcarrier block that interpolates channel state information in each subcarrier block of the first group based on a predetermined interpolation method. is there. Specifically, each component performs the following operation.

Interpolation unit 491 receives the channel state estimation result for each sub carrier block generated in channel estimation unit 205 in FIG. 13, and estimates the channel state of the first group sub carrier block from among them. The result is extracted, and the interpolation value in each subcarrier block of the second group is calculated and output from the channel state estimation result in each subcarrier block of the first group extracted based on a predetermined interpolation method.

[0113] Which subcarrier block is to be a subcarrier block belonging to the first group is The interpolation unit may be determined in advance so that the interpolation result becomes good according to the magnitude of the fluctuation of the channel state estimation result between subcarrier blocks and the speed of the fluctuation in the frequency subcarrier (frequency) direction. It may be determined at 491. In addition, although it is preferable to arrange the subcarrier blocks of the first group at equal intervals (in frequency), it is not limited to this! The grouping of subcarrier blocks or the interpolation method! /, And the like are the same as in the first embodiment, and therefore the description thereof is omitted.

Difference operation unit 492 is a channel state estimation result for each subcarrier block generated in channel estimation unit 205 in FIG. 13, and an interpolation value in each subcarrier block of the second group calculated by interpolation unit 491. If the first group sub-carrier block is determined by the interpolator 491, the determined first group sub-carrier block information (grouping information generated by the interpolator 491), and the interpolator 401 interpolate method When deciding the information, input information (interpolation method information) specifying the determined interpolation method. For each subcarrier block of the first group, the difference operation unit 492 outputs the channel state estimation result as it is as notification information for each subcarrier block as it is, and for each subcarrier block of the second group,! A difference value between the channel state estimation result and the interpolation value is obtained, and the difference value is output as notification information for each subcarrier block. In order to suppress the information amount of notification information, it is preferable to select the difference value from a value that can be expressed by the number of bits smaller than the number of bits necessary to express the propagation path state estimation result. Further, the notification information generation device 490 holds several candidate values as a notification information based on difference values in advance as a table (for example, in the difference calculation unit 492), and the difference calculation unit 492 selects from the table. You may do so.

The difference operation unit 492 generates grouping information from the force interpolation unit 491 that generates notification information based on the channel estimation result in the first group subcarrier block and the difference value in the second group subcarrier block, When interpolation method information or both are notified, the information is also included in the notification information to notify the base station apparatus 100.

The restoration calculation unit 493 calculates the notification information generated by the difference calculation unit 492, the interpolation value in each subcarrier block of the second group calculated by the interpolation unit 491, and the interpolation unit. When the subcarrier block of the first group is determined in 491, the subcarrier block information of the determined first group is input, and the notification information of each subcarrier block of the first group is used as it is. The channel state information is output as a reconstructed channel state estimation result (reconstructed channel quality information) in each subcarrier block, and for each subcarrier block of the second group, the notification information and the interpolation value are added, and the sum value Is output as the restored channel state estimation result in each subcarrier block

The processing of each component of the notification information generating device 490 other than the above is the same as that of the first embodiment.

FIG. 15 shows an example of a block diagram of the notification information restoration unit 390 in the present embodiment. The notification information restoration unit 390 includes an interpolation unit 391 and a restoration calculation unit 392. The restoration operation unit 302 shown in FIG. 5 outputs the restored modulation parameter, but the difference is that the restoration operation unit 392 outputs the restored channel state estimation result. The other parts are the same as in FIG. Interpolation section 391 receives the notification information, and notifies information on each subcarrier block of the first group among them, that is, from the channel state estimation result, based on the interpolation method determined in advance, each subcarrier of the second group. Calculate the interpolation value in the block. The calculation method of this interpolation value is the same as that of the interpolation unit 491 in the notification information generation device 490.

The restoration calculation unit 392 receives the notification information and the interpolation value in each subcarrier block of the second group calculated by the interpolation unit 391, and the notification information is input for each subcarrier block of the first group. The channel state estimation result is output as a reconstructed channel state estimation result for each subcarrier block as it is, and for each subcarrier block of the second group, the notification information and the interpolation value are added, and the addition value is restored for each subcarrier block. Output as the estimated propagation path state. The other points are the same as in FIG.

FIG. 16 shows an example of a block diagram of notification information generating apparatus 500 in base station apparatus 190 in FIG. The notification information generation device 500 includes an interpolation unit 501, a difference calculation unit 502, and a restoration calculation unit 503. The interpolation unit 501 receives the modulation nomometer (selected modulation parameter) selected by the modulation parameter selection unit 191, and performs the same processing as that of the interpolation unit 401 in FIG. The interpolation value is calculated, and the calculated interpolation value is output to the difference calculation unit 502 and the restoration calculation unit 503. The difference calculation unit 502 inputs the selected modulation parameter and the interpolation value, performs the same process as the difference calculation unit 402 in FIG. 3 to generate notification information, and generates the notification information generated. And the multi-pretus unit 103. The restoration calculation unit 503 inputs the interpolation value and the notification information, performs the same process as the restoration calculation unit 403 in FIG. 3 to calculate a restored modulation nomometer, and calculates the calculated restoration modulation parameter. It outputs to the interpolation unit 501 and the adaptive modulation control unit 112. As described with reference to FIG. 11, in the case where the interpolation unit 501 does not perform feedback processing regarding interpolation, the restoration operation unit 503 does not have to output the restored modulation parameters to the interpolation unit 501. Therefore, the output from the restoration operation unit 503 shown by the dotted line in FIG.

The specific example of the notification information shown in FIGS. 7 to 10 and the restoration thereof in the first embodiment is the same as the downlink notification information. Also, for uplink notification information, although the “modulation parameter” changes to the “channel state estimation result” and the range of possible values (such as the number of bits) changes, the procedure is the same.

Thus, according to the present embodiment, when the channel state estimation result is notified to the communication destination as channel quality information, in the first group, the channel state estimation result is used as notification information as it is, and the second group is used. In the first group, the difference value between the interpolated value obtained from the channel state estimation result in the first group and the channel state estimation result is notified as notification information, and the accuracy of the channel quality information restored while reducing the amount of notification information. Force S to improve.

Third Embodiment

In the first embodiment, the modulation parameter restored based on the uplink notification information notified from the terminal device 200 is used, but in the present embodiment, the modulation parameter is changed in the base station device. The base station apparatus of this embodiment can be realized by changing the base station apparatus 190 shown in FIG. 12 as follows. First, in place of the notification information restoring unit 390, the notification information restoring unit 300 shown in FIG. 5 is disposed so that the notification information generated based on the modulation parameter can be restored as channel quality information. Next, instead of the modulation parameter selection unit 191, based on the modulation parameters already selected instead of the channel state estimation result, a new one is generated. A modulation parameter change unit (modulation parameter selection unit) that enables selection of various modulation parameters is arranged. Furthermore, the modulation parameter change unit to be newly arranged has a function of receiving an input of information serving as a reference for changing the already selected modulation parameter, and selecting a new modulation parameter based on the received information. The modulation parameters may be selected (changed) based on predetermined rules. In addition, the notification information generation device 500 has the same function as in FIG. 16! /!

Even when a function of changing the modulation parameter is added to the base station apparatus, notification information is generated based on the changed modulation parameter by providing the notification information generation apparatus 500, and the restored modulation parameter is It can be output. The adaptive modulation control unit 112 controls the modulation of the downlink data signal using the restored modulation parameter calculated by the notification information generating apparatus 500 based on the newly selected modulation parameter. Also, the multiplexer unit 103 multiplexes the notification information generated by the notification information generation apparatus 500 using the newly selected modulation parameter. In this way, since it is possible to notify the terminal apparatus 200 and 290 of the changed modulation parameter, the present invention can be applied to the case where the modulation parameter is changed in the base station apparatus, and notification information The accuracy of channel quality information to be restored can be improved (maintained) while suppressing the amount of information.

Further, the notification information generation apparatus of each of the above embodiments can be realized by hardware such as a circuit or software. When implemented by software, it can be implemented by a notification information generation program related to the operation of a computer. The notification information generation program is loaded into the memory in the computer (in the communication device) and executed under control of the central processing unit (CPU). The notification information generation program calculates and calculates an interpolation value to interpolate the selected channel quality information in the other channels based on the channel quality information in two or more channels selected from the plurality of channels. A program that implements a function of generating notification information based on a difference value indicating a difference between an interpolation value and channel quality information in the other channel, and channel quality information in the two or more selected channels. Basically, it has a function to make a computer (communication device) execute the following procedure.

Procedure for inputting channel quality information in a plurality of channels, and from a plurality of channels A procedure of dividing two or more channels into a first selected group and a second group including other channels not selected as the first group, and the second based on channel quality information in the first group of channels. A procedure for calculating the interpolation value in the channels of the group, a procedure for generating channel quality information in each channel as notification information for the channels in the first group, and a procedure for the second group of channels! A procedure of generating the difference value in the channel and generating the generated difference value as notification information. Furthermore, the above procedure is an example, and further includes a procedure for realizing the functions described in each of the above embodiments.

As described above, according to the preferred embodiment of the present invention, when channel quality information is notified using differences, channel quality information is used as notification information in the channels of the first group. In the second group of channels, the channel quality information is reduced while the amount of notification information is reduced by notifying the difference value between the interpolation value obtained from the channel quality information in the first group and the channel quality information as notification information. Ability to improve (maintain) information accuracy. In addition, by reducing the amount of information to be notified, it is possible to improve system throughput and reduce power consumption.

Brief description of the drawings

FIG. 1 is a block diagram showing a configuration example of a base station apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an example of the configuration of a terminal according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of functional blocks of a notification information generation apparatus in the terminal device of FIG. 2;

FIG. 4 is a flowchart showing an example of an operation of generating notification information in the first embodiment.

FIG. 5 is a view showing an example of a functional block of a notification information restoration unit in the first embodiment.

FIG. 6 is a flowchart showing an example of an operation of restoring notification information in the first embodiment. [FIG. 7] shows an example of a selected modulation parameter which is an input of the notification information generating apparatus in the first embodiment, and an interpolation value, a generation result of notification information, and a restored modulation parameter by the notification information generating apparatus. FIG.

FIG. 8 is a graph showing selected modulation parameters, interpolation values, notification information and restored modulation parameters shown in the example of FIG. 7 and interpolation straight lines.

[FIG. 9] Another example of the selected modulation parameter which is the input of the notification information generating apparatus in the first embodiment, and the interpolation value, the generation result of the notification information, and the restored modulation parameter by the notification information generating apparatus Indicates

FIG. 10 is a graph showing selected modulation parameters, interpolation values, notification information, restored modulation parameters, and spline interpolation curves shown in the example of FIG. 9;

[FIG. 11] A diagram showing another example of functional blocks of a notification information generating device in the terminal device of FIG.

FIG. 12 is a block diagram showing a configuration example of a base station apparatus in the second embodiment according to the present invention.

FIG. 13 is a block diagram showing an example of the configuration of a terminal according to a second embodiment of the present invention.

14 is a diagram showing an example of functional blocks of a notification information generation apparatus in the terminal apparatus of FIG. 13;

FIG. 15 is a diagram showing an example of a functional block of a notification information restoring unit in the second embodiment.

16 is a diagram showing an example of functional blocks of a notification information generating apparatus in the base station apparatus of FIG. 12;

FIG. 17 is a block diagram showing an example of a configuration of a notification information generating apparatus for generating conventional notification information.

Explanation of sign

100, 190 base station equipment

101, 210 error correction coding unit

102, 211 modulation unit 103, 212 multi-pretus part

104 Inverse free transform unit

105, 213 wireless transmitter

106, 107, 201, 214 ante

108, 202 wireless receiver

109, 204 Demultiplexing section

110, 208 demodulator

11 1, 209 Error correction decoding unit

112 Adaptive modulation control unit

191, 206 Modulation parameter selector

200, 290 terminal equipment

203 Fourier Transform Unit

05 Channel estimation unit

07 Adaptive demodulation control unit

00, 390 Notification information restorer

01, 391, 401, 491, 501 Interpolation unit 02, 392, 403, 493, 503 Restoration operation unit 00, 410, 490, 500 Notification information generation device 02, 492, 502 Difference operation unit

Claims

The scope of the claims

[1] A notification information generation apparatus that generates notification information based on channel quality information obtained from the reception state of each channel in a communication method in which communication is performed using a plurality of channels.

Based on channel quality information in two or more channels selected from the plurality of channels, an interpolation value for interpolating channel quality information in other channels not selected is calculated, and the calculated interpolation value and the channel in the other channel are calculated. A notification information generating apparatus characterized by generating notification information based on a difference value indicating a difference with quality information and channel quality information in the two or more selected channels.

[2] A second group including channel quality information of the plurality of channels, a first group in which two or more channels are selected from the plurality of channels, and other channels not selected as the first group. An interpolation unit for calculating the interpolation value in the second group of channels based on channel quality information in the first group of channels;

Channel quality information in each channel is generated as notification information for the first group of channels, the difference value in each channel is generated for the second group of channels, and the generated difference value is used as notification information. The notification information generation apparatus according to claim 1, comprising: a difference calculation unit to generate.

[3] The interpolation value and the notification information are input, and channel quality information in each channel of the notification information is restored as restoration information for the channels of the first group, and the channels of the second group are added! The notification information generation according to claim 2, further comprising a restoration operation unit that restores channel quality information in each channel as restoration information based on the interpolation value and the difference value indicated by the notification information. apparatus.

[4] The interpolation unit determines the number of channels to be selected as the first group and the selection method of the channels based on channel quality information in the plurality of channels, and determines the selection method. 4. The notification information generating apparatus according to claim 2 or 3, wherein the determined number of channels is selected.

[5] The difference calculation unit is configured to determine whether the second group of channels is in each channel. The difference between the interpolation value and the channel quality information is calculated, and a difference value indicating the calculated difference is generated using a preset value, and the difference value is generated according to any one of claims 2 to 4. Notification information generator of.

[6] The interpolation unit inputs the restoration information restored by the restoration calculation unit, and the interpolation method calculates the interpolation value based on the channel quality information and the restoration information, and is selected as the first group 4. The notification information generation apparatus according to claim 3, wherein at least one of the number of channels to be selected or the selection method of channels to be selected as the first group is changed.

[7] A communication device for performing communication using a plurality of channels,

A notification information generation apparatus according to any one of claims 1 to 6,

A transmitter configured to transmit the notification information generated by the notification information generator to the other party of communication.

[8] A notification information generation method for generating notification information based on channel quality information obtained from the reception state of each channel in a communication method in which communication is performed using a plurality of channels.

Based on channel quality information in two or more channels selected from the plurality of channels, an interpolation value to interpolate channel quality information in other channels not selected is calculated.

Notification information generation characterized by generating notification information based on a difference value indicating a difference between the calculated interpolation value and channel quality information in the other channel, and channel quality information in the two or more selected channels. Method.

[9] A notification information generation program for causing a computer to execute a procedure for generating notification information based on channel quality information obtained from the state of reception of each channel in a communication method in which communication is performed using a plurality of channels. ,

Inputting channel quality information in the plurality of channels;

A step of dividing two or more channels from the plurality of channels into a first group and a second group including other channels not selected as the first group, and channels in the channels of the first group The second nig based on the quality information Calculating said interpolated value in the channel of the loop;

Generating channel quality information in each channel as notification information for the first group of channels;

A notification information generation program for causing a computer to execute a procedure of generating the difference value of each channel and generating the generated difference value as notification information for the channels of the second group.