WO2006112133A1 - Wireless transmitter and wireless communication system - Google Patents

Abstract

[PROBLEMS] To improve transmission efficiency on a link for informing propagation path information, while suppressing generation of an error during communication. [MEANS FOR SOLVING PROBLEMS] A wireless transmitter is provided with an SIR estimating section (207) for estimating a reception SIR from a wireless signal received from the other party of communication; an SIR information creating section (210) for creating wireless propagation path information wherein a reception SIR value of a specified subcarrier is decimated in accordance with the estimation results of the SIR estimating section (207); and an upstream link transmission processing section (211) for transmitting the wireless propagation path information created by the SIR information creating section (210) to the other party of communication. The SIR information creating section (210) creates the wireless propagation path information only from the reception SIR values for every prescribed number of subcarriers, a number of the subcarrier having the largest error compared with an actual reception SIR value and the reception SIR value.

Description

 Radio transmitter and radio communication system

 Technical field

 [0001] The present invention relates to a radio transmitter that performs high-speed communication by adaptively changing a modulation scheme, a coding rate, and the like for each subcarrier based on a radio channel state on the receiver side, and a radio including the radio transmitter The present invention relates to a communication system.

 Background art

 [0002] Currently, in high-speed mobile communication, a radio propagation path between a radio base station (hereinafter referred to as "base station") and a radio mobile station (hereinafter referred to as "mobile station"). By controlling the modulation method and coding rate (MCS: Modulation and Code Scheme) according to the state, the transmission efficiency is improved, and the adaptive modulation method that provides high-throughput communication and the wireless channel state for each user can be wireless. Research / development of the OFDMA system that performs high-speed communication by assigning subcarriers with good propagation path conditions to each user!

 [0003] In such a communication scheme in which adaptive modulation is performed for each subcarrier according to the radio propagation path state and a communication scheme in which subcarriers are allocated to each user according to the radio propagation path state, Understand the status of received power, etc. for each subcarrier received by the mobile station in order to change the modulation method and code rate for the carrier, or to assign subcarriers with good radio channel conditions to the user There is a need. On the other hand, the mobile station measures the radio propagation path conditions such as the received SIR (Signal to Interference Power Ratio) and digitizes the received SIR information of all subcarriers measured by the mobile station. Periodically transmit to the base station.

[0004] Specifically, as shown in FIG. 21, the base station transmits a signal with constant transmission power for each subcarrier to the mobile station. At the point of the mobile station, the signal transmitted from the base station in this way is attenuated for each subcarrier due to the influence of frequency fading as shown in FIG. The mobile station calculates the received SIR of all subcarriers from the known signal (pilot signal) included in the frame, digitizes the calculated received SIR information of all subcarriers, and periodically transmits it to the base station side. The base station receives the received signal from the mobile station. From the received SIR information, for example, the modulation scheme and coding rate are determined for each subcarrier based on the threshold set as shown in FIG. 23, and the data is transmitted to the mobile station!

[0005] In addition, when the received SIR information of all subcarriers measured by the mobile station is transmitted to the base station side, the amount of information should be reduced, as shown in FIG. A method has been proposed in which the average value of received SIRs of subcarriers in each block is calculated, and the average value of each block is notified to the base station (for example, see Non-Patent Document 1). . Non-patent document 1: Kazunari Yokomakura, Seiichi Sampei, Norihiko Morinaga, “Study on interference power estimation and notification technology in 1-cell repeated OFDMZTDMA system using adaptive modulation”, IEICE Technical Report RCS2003 — 240 p. 33— 38, 2003 Invention Disclosure

 Problems to be solved by the invention

 [0006] However, since the amount of information of the radio propagation path such as the conventional reception SIR is allocated several bits per subcarrier, the reception SIR of the reception SIR depends on the number of subcarriers. There is a problem that the amount of information increases. At present, many of the adaptive modulation communication systems that are considered use hundreds of subcarriers, and several kilobits are required to transmit the corresponding number of received SIRs. The amount of radio propagation information is required. In addition, since the adaptive modulation scheme periodically changes the modulation scheme, the mobile station must periodically notify the base station of the propagation path information in accordance with the base station cycle. For this reason, in the uplink, the usage rate of the amount of channel information is large, and the transmission efficiency is poor. Furthermore, in such a communication system, it is assumed that the transmission rate of the uplink to the mobile station and the transmission rate of the uplink to the base station is lower than that of the downlink to the mobile station. As a result, transmission efficiency is further deteriorated.

[0007] In addition, in the method disclosed in Non-Patent Document 1, there are subcarriers with good radio conditions and bad subcarriers within the blocked subcarrier group. Therefore, when these are averaged, as shown in FIG. 25, a modulation scheme having a high modulation degree is not selected for subcarriers with good radio conditions, and transmission efficiency deteriorates, or conversely, The problem is that a modulation scheme with a high degree of modulation is selected for a bad subcarrier and the number of errors increases, and the optimum modulation scheme is not selected for the subcarrier, resulting in a decrease in transmission efficiency. There is a title.

 The present invention has been made in view of such conventional problems, and improves transmission efficiency on a link that notifies channel information while suppressing the occurrence of errors during communication. An object of the present invention is to provide a wireless transmitter capable of performing the above and a wireless communication system including the same. Means for solving the problem

 (1) In order to achieve the above object, the present invention takes the following measures. That is, a wireless transmitter according to the present invention includes a propagation path state estimation unit that estimates a propagation path state from a radio signal received from a communication partner, and a specific subcarrier according to an estimation result by the propagation path state estimation unit. A propagation path information creation unit that creates propagation path information obtained by decimating a value indicating the propagation path status, and a transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner. It is characterized by.

 [0010] In this way, since the propagation path information creation unit creates propagation path information by thinning out the value indicating the propagation path condition of a specific subcarrier, the value indicating the propagation path condition of all subcarriers is notified. Compared with the case where the transmission is performed, it is possible to improve the transmission efficiency on the link for notifying the propagation path information.

 [0011] (2) Further, in the radio transmitter according to the present invention, the propagation path information creation unit is adjacent to the value indicating the propagation path condition for the subcarriers selected for each predetermined number and the selected neighbor. Produce force propagation path information only from the value obtained by linear interpolation from the value indicating the propagation path condition for the subcarrier and the subcarrier number having the value indicating the propagation path condition with the largest error and the value indicating the propagation path condition. It is characterized by.

[0012] In this way, the value indicating the propagation path condition for the subcarriers selected for each predetermined number and the value linearly interpolated from the value indicating the propagation path condition for the selected adjacent subcarriers are the most error. Since the propagation path information is created only from the subcarrier number having a value indicating a large propagation path condition and the value indicating the propagation path condition, the value indicating the propagation path condition of all the subcarriers is notified. Compared to this, it is possible to improve the transmission efficiency on the link that notifies the propagation path information. Also, since the subcarrier number with the largest error and the value indicating the propagation path status are notified, the communication scheme can correct the coding rate, for example, based on such information. This is not compatible with radio conditions Since it is possible to avoid a situation where communication errors increase due to the selection of a modulation method, etc., it is possible to suppress the occurrence of errors during communication.

 [0013] (3) Further, in the radio transmitter according to the present invention, the propagation path information creation unit has a slope of a curve obtained by connecting a value indicating a propagation path condition for each subcarrier in advance. It is characterized in that the propagation path information is created only from the subcarrier number and the value indicating the propagation path status when it changes by more than a fixed value.

 [0014] Thus, only the subcarrier number and the value indicating the propagation path condition when the slope of the curve obtained by linking the value indicating the propagation path condition for each subcarrier changes by a predetermined value or more. Since the propagation path information is created from the network, the amount of wireless propagation path information can be significantly reduced compared to the case where a value indicating the propagation path status of all subcarriers is notified, and the link information for reporting the propagation path information can be reduced. The transmission efficiency can be improved. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope of the curve changes by a certain value or more are notified, the value indicating the actual propagation path condition and the value indicating the propagation path condition significantly deviated. Can be prevented from being notified. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the radio state is selected and communication errors increase, and thus it is possible to suppress the occurrence of errors during communication.

 [0015] (4) In the radio transmitter according to the present invention, the propagation path information creation unit includes a sign of a slope of a curve obtained by connecting a value indicating a propagation path condition for each subcarrier. It is characterized in that force propagation path information is created only with a subcarrier number and a value indicating the propagation path state when the value changes.

[0016] In this way, only the subcarrier number and the value indicating the propagation path condition when the sign of the slope of the curve obtained by connecting the value indicating the propagation path condition for each subcarrier is changed. Therefore, the amount of radio channel information can be significantly reduced compared to the case where a value indicating the channel status of all subcarriers is reported, and the transmission efficiency on the link that reports channel information is improved. Can be improved. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope in the above curve is reversed are notified, the value indicating the actual propagation path condition and the value indicating the propagation path condition significantly deviated are notified. Can be prevented. As a result, a modulation method that does not match the radio conditions is selected. As a result, it is possible to avoid an increase in communication errors, and it is possible to suppress the occurrence of errors during communication.

 [0017] (5) Also, in the radio transmitter according to the present invention, the propagation path information creation unit includes a sign of a slope of a curve obtained by connecting a value indicating a propagation path condition for each subcarrier. Propagation is based only on the value indicating the subcarrier number and the propagation path condition when the signal changes, and the value indicating the propagation path condition for the subcarrier arranged in the middle between the subcarrier numbers where the sign of the curve changes. It is characterized by creating road information.

 [0018] Thus, when the sign of the slope of the curve obtained by connecting the values indicating the propagation path conditions for each subcarrier changes, the subcarrier number, the value indicating the propagation path condition, and the slope of the curve Because the channel information is created only from the values indicating the channel conditions for the subcarriers placed in the middle between the subcarrier numbers whose codes have changed, when notifying the values indicating the channel conditions of all subcarriers Compared to the above, it is possible to significantly reduce the amount of radio channel information, and to improve the transmission efficiency on the link that notifies the channel information. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope in the above curve is reversed are notified, the value indicating the actual propagation path condition and the value indicating the propagation path condition significantly deviated are notified. Can be prevented. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the wireless state is selected and a communication error increases, and thus it is possible to suppress the occurrence of an error during communication. Further, since a value indicating the propagation path status of the subcarriers arranged in the middle between the subcarrier numbers whose slopes in the above curve are reversed is notified, for example, at the communication partner, for example, the modulation method ' The coding rate can be modified. As a result, it is possible to select a modulation method or the like that is more suitable for the wireless state, and it is possible to further suppress the occurrence of errors during communication.

 [0019] (6) In the radio transmitter according to the present invention, the propagation path information creation unit is a sign of a slope of a curve obtained by connecting a value indicating a propagation path condition for each subcarrier. Only when the subcarrier number has a value indicating the propagation path condition between the subcarrier number and the propagation path condition when the value of the curve changes, and the intermediate propagation path condition between the subcarrier numbers where the sign of the slope of the curve has changed. It is characterized by creating information.

[0020] Thus, a curve obtained by connecting values indicating propagation path conditions for each subcarrier. Only a subcarrier number having a value indicating a subcarrier number and a propagation path condition when the sign of the slope of the curve changes, and a value indicating an intermediate propagation path condition between subcarrier numbers where the sign of the slope of the curve is changed Since the propagation path information is created, the amount of wireless propagation path information can be significantly reduced compared to the case where the values indicating the propagation path conditions of all subcarriers are notified, and the link that notifies the propagation path information. The above transmission efficiency can be improved. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope in the above curve is reversed are notified, the value indicating the actual propagation path condition and the value indicating the propagation path condition significantly deviated are notified. Can be prevented. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the radio state is selected and communication errors increase, and thus it is possible to suppress the occurrence of errors during communication. Further, since the subcarrier number having a value indicating the intermediate channel condition between the values indicating the channel condition of the subcarrier number whose slope in the above curve is reversed is notified, the communication is performed based on the information. At the other end, for example, the modulation scheme 'coding rate can be modified. As a result, it is possible to select a modulation method or the like that is more suitable for the radio state, and it is possible to further suppress the occurrence of errors during communication.

 (7) Further, in the radio transmitter according to the present invention, the propagation path information creation unit selects the method with the smallest data amount of the propagation path information and selects the propagation path information. It is characterized by creating.

 In this way, the propagation path information creation unit creates the propagation path information by selecting the method with the smallest data amount of the propagation path information, so that the transmission efficiency can be improved most. It is possible to notify the communication partner of the propagation path information by selecting a method.

 [0023] (8) In the radio transmitter according to the present invention, the propagation path state estimation unit uses a received SIR (Signal to Interference Power Ratio) as a propagation path state. It is characterized by estimation.

 [0024] (9) Further, in the radio transmitter according to the present invention, the propagation path condition estimation unit uses a received SNR (Signal to Noise Power Ratio) as a propagation path condition. It is characterized by estimating.

[0025] (10) In the wireless transmitter according to the present invention, the propagation path condition estimation unit may Received as SINR (Signal to Interference Plus Noise Power Ratio

: Signal power to interference noise power ratio).

[0026] As described above, the propagation path condition estimation unit estimates the reception SIR, the reception SNR, and the reception SINR as the propagation path condition, so that the propagation path condition can be estimated appropriately.

[0027] (11) Further, the mobile station apparatus according to the present invention is characterized by including the radio transmitter according to any one of claims 1 to 10.

[0028] Thus, since the mobile station apparatus includes the above-described radio transmitter, the mobile station apparatus is on the link that notifies the channel information compared to the case where the values indicating the channel conditions of all the subcarriers are notified. The transmission efficiency can be improved, and the effects obtained by the radio transmitter according to each claim can be obtained also by the mobile station apparatus.

[0029] (12) Further, a base station apparatus according to the present invention is characterized by including the radio transmitter according to any one of claims 1 to 10.

[0030] In this way, since the base station apparatus includes the above-described wireless transmitter, it is on the link that notifies the propagation path information compared to the case where the values indicating the propagation path conditions of all subcarriers are notified. The transmission efficiency can be improved, and the effects obtained by the radio transmitter according to each claim can also be obtained by the base station apparatus.

[0031] (13) Further, a radio communication system according to the present invention uses the mobile station device according to any one of claims 8 to 10 and the propagation path information received from the mobile station device to And a base station apparatus that determines a modulation scheme and a code rate for each carrier.

 [0032] Thus, since the wireless communication system includes the mobile station apparatus according to any one of claims 8 to 10, the wireless communication system includes values indicating propagation path conditions of all subcarriers. Compared with the case of notification, it is possible to improve the transmission efficiency on the link for notifying the propagation path information.

 The invention's effect

[0033] According to the wireless transmitter and the wireless communication system of the present invention, it is possible to improve the transmission efficiency on the link that notifies the propagation path information while suppressing the occurrence of errors during communication. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of a wireless communication system according to the present invention will be specifically described with reference to the drawings.

 FIG. 1 is a block diagram showing a configuration of a base station apparatus (hereinafter referred to as “base station”) 100 constituting the radio communication system according to the embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of mobile station apparatus (hereinafter referred to as “mobile station”) 200 constituting the communication system according to the embodiment of the present invention.

 In base station 100 shown in FIG. 1, coding section 101 uses a coding scheme such as turbo coding for transmission data generated by an external device, and instructs it from an MCS allocation section described later. Data is encoded at the encoded rate. The data modulation unit 102 performs modulation processing on the code data from the encoding unit 101 according to a modulation scheme instructed by the MCS allocation unit described later. A serial Z parallel conversion unit (SZP conversion unit) 103 performs serial Z parallel conversion on the modulation data from the data modulation unit 102 and converts it into modulated data that has been processed in parallel according to the number of subcarriers.

 [0037] Multiplexing section (Mux section) 104 is a pilot signal for mobile station 200 to estimate the received SIR of the modulated data converted in parallel to the number of subcarriers, and each sub-line from MLI generating section 111 described later. It is multiplexed with modulation / code information (MLI: Multi-vel information) that describes the carrier modulation method and code rate. Note that a pilot signal used for multiplexing is delivered from the pilot generation unit 105 at a predetermined timing. The inverse fast Fourier transform unit (IFFT unit) 106 performs inverse Fourier transform on the multiplexed data from the Mux unit 104 and converts it into an OFDM signal. Radio transmitting section 107 up-converts the OFDM signal to the radio frequency band, and transmits the sub-carrier to the mobile station with a constant transmission power.

 [0038] Uplink reception processing section 108 receives data from mobile station 200, and separates the received data from received SIR information estimated by the mobile station. The received data is sent to the external device, and the received SIR information is sent to the SIR information extraction unit 109. Note that the reception form of the demodulation unit in base station 100 is not necessarily provided with the capability of adaptive modulation reception.

[0039] From the received SIR information received from uplink reception processing section 108, SIR information extraction section 109 extracts decimation information including the subcarrier number and SIR value transmitted from mobile station 200. Put out. In addition, the thinned information power also calculates the SIR value of the subcarrier thinned out on the mobile station 200 side by linearly interpolating between specific received SIR values. Further, the reception SIR values of all subcarriers are sent to MCS allocation section 110.

 [0040] MCS allocating section 110 determines MCS of each subcarrier from the calculated SIR value of each subcarrier, and provides code rate and code modulation ratio to code key section 101 and data modulation section 102, respectively. Indicates the modulation method. Also, the MCS information in each subcarrier this time is passed to the MLI generation unit 111. The MLI generation unit 111 assembles MCS information of each subcarrier, performs modulation and encoding at a modulation scheme and coding rate that the mobile station 200 can receive in any environment, and passes the generated MLI to the Mux unit 104 .

 [0041] It should be noted that the modulation scheme and code rate performed by MLI generating section 111 are determined in advance between base station 100 and mobile station 200, and the scheme and the like are fixed. In addition, since MLI must be able to be received by mobile station 200 under any circumstances, it is desirable that the number of modulation multi-values is as low as possible (such as BPSK and QPSK) and that the code rate is low.

 On the other hand, in mobile station 200 shown in FIG. 2, radio reception section 201 receives the radio signal from base station 100 and down-converts the radio signal in the radio frequency band to the IF frequency band. A fast Fourier transform unit (FFT unit) 202 performs Fourier transform and returns the OFDM signal to modulation data. The DeMux unit 203 separates the multiplexed modulation data, and sends the modulation data to the parallel Z-serial conversion unit (PZS conversion unit) 204, the MLI to the MLI extraction unit 206, and the pilot signal to the SIR estimation unit 207.

 A parallel Z-serial conversion unit (PZS conversion unit) 204 performs parallel Z-serial conversion on the modulated data processed in parallel to the number of subcarriers, returns the modulated data to one column, and sends the data to the data demodulation unit 205. The data demodulating unit 205 demodulates the modulated data by the demodulation method instructed according to the instruction of the MCS control unit 209, which will be described later, and returns it to the encoded data. Decoding section 208 decodes the encoded data by a method instructed in accordance with an instruction from MCS control section 209 described later, and restores the original data.

[0044] The MLI extraction unit 206 performs demodulation and decoding processing for returning the modulation and coding scheme performed on the MLI in the base station 100, and sends the MLI data to the MCS control unit 209. The MCS control unit 209 determines the MCS of each subcarrier from the MLI data, and the data demodulation unit 205 And the decoding key unit 208 is controlled.

 [0045] SIR estimation section 207 also estimates the received SIR of each subcarrier in terms of pilot signal power. At this time, the estimated received SIR is the SIR smoothed between the subcarriers. The SIR information creation unit 210 creates SIR information to be sent to the base station 100 from the received SIR value in each subcarrier from the SIR estimation unit 207 by using the below-described I-bow algorithm, and the uplink transmission processing unit Pass to 211. Uplink transmission processing section 211 multiplexes this SIR information and transmission data, and transmits them to base station 100 as radio signals.

 [0046] Note that regarding the uplink side communication control on the receiving side in the base station 100 and on the transmitting side in the mobile station 200, the adaptive modulation control may not be particularly used.

 [0047] In the communication system according to the present embodiment, when receiving SIR information on all subcarriers measured by mobile station 100 is transmitted to base station 100, the received SIR value of a specific subcarrier is thinned out. This reduces the amount of information and avoids a decrease in transmission efficiency and an increase in errors during communication that can occur by not reporting the received SIR values of all subcarriers. Hereinafter, an algorithm (hereinafter referred to as “decimation algorithm”) used when thinning the received SIR value in a specific subcarrier will be described.

 [0048] The thinning algorithm described above is used when the SIR information creation unit 210 in the mobile station 200 creates SIR information to be transmitted to the base station 100. The SIR information creation unit 210 can use the following thinning algorithm alone or can be switched depending on the situation such as an error in the radio propagation path. Hereinafter, the first to fifth decimation algorithms used in the SIR information creation unit 210 will be described.

 [0049] First, the first thinning algorithm will be described. The first decimation algorithm calculates the subcarrier number and received SIR value with the largest error from the actual received SIR value from the value indicated by the straight line connecting the received SIR value and the received SIR value of every m subcarriers. It is something to detect. By notifying base station 100 only of the received SIR values of the detected subcarrier number subcarriers and every m subcarriers, the received SIR values of other subcarriers are thinned out as a result.

FIG. 3 is a diagram for explaining the outline of the first thinning algorithm. FIG. 4 is a flowchart for explaining the first thinning algorithm. In addition, Figure 5 FIG. 3 is a diagram showing an example of a frame format used for notifying a base station 100 of a reception SIR value of a subcarrier specified by using a thinning algorithm of 1.

 [0051] In the first decimation algorithm, as shown in Fig. 3, after extracting the received SIR values of every m subcarriers (every 10 in Fig. 3), linear interpolation is performed between the received SIR values. (Linear interpolated values are indicated by dotted lines). Then, the difference between the linearly interpolated value and the actual received SIR value is calculated, and the subcarrier number and received SIR value with the largest error are extracted.

 [0052] The frame format used for notification to base station 100 describes the reception SIR value of each of m subcarriers, and the subcarrier number and reception SIR value that are the maximum error between m. . Using the example shown in FIG. 3, between the first and eleventh subcarriers, the subcarrier number with the largest error from the actual received SIR value and the received SIR value are the fifth subcarrier number and The received SIR value will be notified.

 For the specific algorithm, as shown in FIG. 4, first, after initializing the reference number i (i = 0) (step SI), the received SIR value of the first subcarrier is converted into a frame format. Add (step S2).

 Next, it is determined whether (m * (i + 1) +1) exceeds the total number of subcarriers n (step S3), and if it is lower, the reference number i is incremented (step S4). , Step S2 to Step S4 are repeated. By repeating this process, the SIR value of the (m + 1) th subcarrier is added to the frame format when the reference number i indicates “1”, and the (2m + 1) th when the reference number i indicates “2”. SIR values of subcarriers are added to the format. Similarly, SIR values for every m subcarriers are added to the format up to the nth subcarrier.

 [0055] On the other hand, if the determination result exceeds the determination in step S3, after initializing the reference number i (i = 0) (step S5), (m * i + 1) A slope d between the reception SIR value of the th subcarrier and the reception SIR value of (m * (i + 1) +1) th subcarrier is calculated (step S6).

[0056] Then, after initializing the reference number j (j = l) and initializing the maximum error h (h = 0) (step S7), the slope d and the (m * i + 1) -th sub The error g is calculated using the received SIR value of the carrier and the received SIR value of the (m * i + j + 1) th subcarrier (step S8). Here, the received SIR value of the first subcarrier is interpolated with the received SIR value of the second subcarrier. Obtain the SIR value of the second subcarrier, and calculate the error g between the SIR value of the second subcarrier obtained by interpolation and the actual received SIR value.

 [0057] Determine whether the error g calculated in step S8 is larger than the maximum error h (step S9). If it is larger, substitute the error g calculated in step S8 for the maximum error h (h = g) The subcarrier number t is incremented by the reference number j (t = m * i + j) (step S10). Here, since the error g is calculated first, this error g is substituted as the maximum error h.

 [0058] Then, it is determined whether or not the reference number j + 1 exceeds m (step S11). On the other hand, if the determination in step S9 is smaller, the process of step S10 is skipped and it is directly determined whether the reference number j + 1 is greater than m (step S11). If the judgment result of step S11 exceeds! /, NA! /, After incrementing the reference number j (j = j + 1) (step S1 2), repeat the processing from step S7 to step S12 .

 [0059] By repeating the processing from step S7 to step S12, the error g of the third subcarrier is calculated, and then the error g is compared with the maximum error h. If the error g is larger than the maximum error h, the error g is registered as the maximum error h. If the error g is smaller than the maximum error h, the error g of the fourth subcarrier is calculated and similarly Compare with error h. The above processing is repeated until the m-th subcarrier, and the subcarrier number and SIR value with the maximum error h between the first subcarrier and the (m + 1) th subcarrier are detected.

 On the other hand, if the result of determination in step S11 exceeds the determination result, the subcarrier number t and its received SIR value are added to the frame format (step S13). Then, after incrementing the reference number i (i = i + 1) (step S14), it is determined whether (m * i + 1) exceeds the total number of subcarriers n (step S15).

 [0061] If not, in this case, the process returns to step S7, and the process of steps S7 to S12 is repeated with the reference number i incremented. As a result, the subcarrier number and the received SIR value that are the maximum error h between the (m + 1) th subcarrier and the (2m + 1) th subcarrier are detected. The above processing is repeated until the n-th subcarrier, and the subcarrier number and the received SIR value with the maximum error h in each section are detected and described in the frame format shown in FIG.

[0062] In this way, when the first thinning algorithm is used, sub-units for each predetermined number (m) are used. The subcarrier number having the largest error from the received SIR value of the carrier and the actual received SIR value and the received SIR value are detected and reported to the base station 100 as radio propagation path information. For this reason, the transmission efficiency on the link for notifying the propagation path information can be improved as compared with the case of notifying the reception SIR values of all subcarriers. In addition, since the subcarrier number having the largest error with the actual received SIR value and the received SIR value are notified, the base station 100 must correct the modulation scheme code rate based on such information. Can do. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the radio state is selected and a communication error increases, and it is possible to suppress the occurrence of an error during communication.

[0063] Next, the second thinning algorithm will be described. The second decimation algorithm detects the subcarrier number and the received SIR value when the slope of the curve obtained by connecting the received SIR values (hereinafter referred to as the “received SIR curve”) changes by more than a certain value. To do. By notifying base station 100 of only the subcarrier of the detected subcarrier number and its received SIR value, the received SIR values of other subcarriers are thinned out as a result.

 FIG. 6 is a diagram for explaining the outline of the second thinning algorithm. FIG. 7 is a flowchart for explaining the second thinning algorithm. Further, FIG. 8 is a diagram showing an example of a frame format used for notifying the base station 100 of the reception SIR value of the subcarrier specified by using the second algorithm.

 [0065] In the second decimation algorithm, as shown in Fig. 6, in the received SIR curve, the slope of the received SIR value between each subcarrier is calculated, and the slope between the subcarriers to be calculated is the reference subcarrier. Inclination force between carriers Extracts the subcarrier number and received SIR value when it changes by more than a certain value.

 [0066] In the frame format used for notification to base station 100, the subcarrier number extracted as described above and its received SIR value are described. If the example shown in FIG. 6 is used, the first, fourth, eighth, etc. subcarrier numbers and their received SIR values are described and notified to base station 100.

As for the specific algorithm, as shown in FIG. 7, first, after subcarrier number t is initialized (t = 1) (step S21), the t-th subcarrier number and its received SIR value The Add to frame format (step S22). After the reference number j is initialized (j = l) (step S23), it is determined whether the number of subcarriers indicated by (t + j) is the same as the total number of subcarriers n (step S24). If they are the same, the process proceeds to step S33, and the subcarrier number (t + j) -th subcarrier number and its received SIR value are added to the frame format.

 On the other hand, if it is determined in step S24 that they are not the same, a slope A between the reception SIR value of the t-th subcarrier and the reception SIR value of the (t + j) -th subcarrier is calculated (step S25). Then, a threshold table force shown in FIG. 9 in which thresholds (lower threshold Pmin, upper threshold Pmax) corresponding to the calculated slope A are preset is also searched (step S26). Then, after incrementing the reference number j (j = j + 1) (step S27), it is determined again whether the number of subcarriers indicated by (t + j) is the same as the total number of subcarriers n (step S28). If they are the same, the process proceeds to step S33, and the subcarrier number (t + j) th subcarrier number and its received SIR value are added to the frame format.

 [0069] On the other hand, if it is determined in step S28 that they are not the same, a slope B between the reception SIR value of the t-th subcarrier and the reception SIR value of the (t + j) -th subcarrier is calculated (step S29). Further, a slope C between the received SIR value of the (t + j−1) th subcarrier and the received SIR value of the (t + j) th subcarrier is calculated (step S30). Then, it is determined whether one of the calculated slope B and slope C is a value other than the value between the threshold value Pmin and the threshold value Pmax (step S31).

 [0070] If both slope B and slope C are values between threshold Pmin and threshold Pmax, it is determined that there is no significant change in the received SIR value curve, and the process returns to step S27, and then step S Repeat steps 27 to S31. On the other hand, if either slope B or slope C is a value other than the value between threshold P min and threshold Pmax, it is determined that there is a large change in the received SIR curve, and subcarrier number t is set to (t After substituting + j-1) (step S32), the process returns to step S22. Then, the processing from step S22 to step S32 is repeated.

[0071] Then, while repeating the processing of step S22 to step S32, if it is determined in step S24 or step S28 that it is the same as the total number of subcarriers n, the subcarrier number (t + j) -th sub Carrier number and its received SIR value in frame format Carry out additional charge (step S33) and end the second thinning algorithm.

Here, a specific example in which the subcarrier number t is “1” will be described. In this case, first, in step S22, the first subcarrier number and its received SIR value are added to the frame format. In step S25, after calculating the slope A between the reception SIR value of the first subcarrier and the reception SIR value of the second subcarrier, in step S26, a threshold value corresponding to the slope A (lower threshold Pmin, Search for the upper threshold (Pmax). After that, in step S29, after calculating the slope B between the reception SIR value of the first subcarrier and the reception SIR value of the third subcarrier, the reception of the second subcarrier is performed in step S30. The slope C between the SIR value and the received SIR value of the third subcarrier is calculated. In step S31, the change point of the slope is determined by determining whether one of the slopes B and C is a value other than the value between the lower limit threshold value Pmin and the upper limit threshold value Pmax. That is, if either of the slopes B and C is a value other than the value between the lower threshold Pmin and the upper threshold Pmax, the slope change point is determined as the previous subcarrier, and the second subcarrier number and its Add the received SIR value to the format. By performing such processing up to the nth subcarrier, the subcarrier number and the received SIR value when the slope of the received SIR curve changes by a certain value or more are detected and described in the frame format shown in FIG. .

[0073] In this way, when the second thinning algorithm is used, the subcarrier number and the received SIR value when the slope of the received SIR curve changes by a certain value or more are detected, and the base station is used as radio propagation path information. Notify station 100. For this reason, it is possible to significantly reduce the amount of radio propagation path information compared to notifying the reception SIR values of all subcarriers, and to improve the transmission efficiency on the link that notifies the propagation path information. . Also, since the subcarrier number and the received SIR value when the slope of the received SIR curve changes by a certain value or more are reported, it is possible to prevent the received SIR value from being significantly different from the actual received SIR value. be able to. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the wireless state is selected and communication errors increase, and it is possible to suppress the occurrence of errors during communication.

[0074] Next, the third thinning algorithm will be described. The third decimation algorithm detects the subcarrier number and its received SIR value when the slope in the received SIR curve is reversed (decrease from increased calorie or increase in decremental power). This detected subcarrier number By notifying base station 100 of only the number and its received SIR value, the other subcarrier number and its received SIR value are thinned out as a result.

 FIG. 10 is a diagram for explaining the outline of the third thinning algorithm. FIG. 11 is a flowchart for explaining the third thinning algorithm. Further, FIG. 12 is a diagram showing an example of a frame format used for notifying the base station 100 of the reception SIR value of the subcarrier specified by using the third thinning algorithm V.

 In the third decimation algorithm, as shown in FIG. 10, in the reception SIR curve, the reception SIR value between adjacent subcarriers is compared, and the subcarrier number and reception when the slope in the reception SIR curve is reversed. Extract SIR values.

 [0077] In the frame format used for notification to base station 100, the subcarrier number extracted as described above and its received SIR value are described. If the example shown in FIG. 10 is used, the first, fifth, tenth... Subcarrier numbers and their received SIR values are described and notified to base station 100.

 As for a specific algorithm, as shown in FIG. 11, first, after subcarrier number t is initialized (t = 1) (step S41), the t-th subcarrier number and its received SIR value are set. Add to frame format (step S42). After the reference number j is initialized (j = 1) (step S43), it is determined whether the number of subcarriers indicated by (t + j) is the same as the total number of subcarriers n (step S44). If they are the same, the process proceeds to step S52, and the subcarrier number (t + j) -th subcarrier number and its received SIR value are added to the frame format.

 [0079] On the other hand, if it is determined in step S44 that they are not the same, the difference oc between the reception SIR value of the t-th subcarrier and the reception SIR value of the (t + j) -th subcarrier is calculated (step S45). Then, after incrementing the reference number j (j = j + 1) (step S46), it is again determined whether the number of subcarriers indicated by (t + j) is the same as the total number n of subcarriers (step S47). If they are the same, the process proceeds to step S52, and the subcarrier number (t + j) -th subcarrier number and its received SIR value are added to the frame format.

On the other hand, if it is determined in step S47 that they are not the same, the difference 13 between the reception SIR value of the t-th subcarrier and the reception SIR value of the (t + j) -th subcarrier is calculated (step S48). Then, it is determined whether the difference a is 0 or more and a is larger than | 8, or whether the difference a is less than 0 and a is smaller than β (step S49). If the deviation does not apply, it is determined that there is no reversal of the slope in the received SIR curve, and after substituting the difference j8 for the difference a (a = β) (step S50), the process returns to step S46. Then, the processing from step S46 to step S50 is repeated.

 [0081] On the other hand, if applicable, it is determined that there is an inversion of the slope in the received SIR curve, and (t + j-1) is substituted for subcarrier number t (step S51), and then the process goes to step S42. Return. Then, the processing from step S42 to step S51 is repeated. Then, while repeating the processing of step S42 to step S51, if it is determined in step S44 or step S47 that it is the same as the total number of subcarriers n, the subcarrier number (t + j) th subcarrier number The received SIR value is added to the frame format (step S52), and the third decimation algorithm is terminated.

 Here, a specific example in which the subcarrier number t is “1” will be described. In this case, first, in step S42, the first subcarrier number and its received SIR value are added to the frame format. In step S45, a difference a between the reception SIR value of the first subcarrier and the reception SIR value of the second subcarrier is calculated. Thereafter, in step S48, a difference j8 between the reception SIR value of the first subcarrier and the reception SIR value of the third subcarrier is calculated. Then, in step S49, the difference (difference between X and difference β or the difference between difference a and difference ι8 when X is less than 0 is determined when difference a is 0 or more. Thus, a change point at which the slope in the received SIR curve reverses (hereinafter referred to as “reverse change point”) is determined, that is, when the difference a is 0 or more, the difference oc is greater than the difference β. Is larger, the second subcarrier is determined to be the reverse change point, while the difference (if the difference a is smaller than the difference β when X is less than 0, the second subcarrier is The carrier is determined to be the reverse change point, and the second subcarrier number and its received SIR value are added to the format.By performing such processing up to the nth subcarrier, the slope in the received SIR curve is reversed. Subcarrier number and receipt The detected SIR value is detected and described in the frame format shown in Fig. 12.

[0083] Thus, when the third decimation algorithm is used, the slope in the received SIR curve is The subcarrier number and the received SIR value are detected and the base station 100 is notified as radio propagation path information. For this reason, the amount of radio propagation path information can be greatly reduced compared to the case of notifying the reception SIR values of all subcarriers, and the transmission efficiency on the link for notifying the propagation path information can be improved. . In addition, since the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are reported, it is possible to prevent the received SIR value from being significantly different from the actual received SIR value. it can. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the radio state is selected and communication errors increase, and it is possible to suppress the occurrence of errors during communication.

 Next, the fourth thinning algorithm will be described. The fourth decimation algorithm detects the subcarrier number and its received SIR value when the slope in the received SIR curve is reversed (decreased from increased calorie or increased decremental power), and between the subcarrier numbers whose slope is reversed. This is to detect the reception SIR value of the subcarriers arranged in the middle of. By notifying base station 100 of only the detected subcarrier number and its received SIR value, other subcarrier numbers and its received SIR values are thinned out as a result.

 FIG. 13 is a diagram for explaining the outline of the fourth thinning algorithm. FIG. 14 is a flowchart for explaining the fourth thinning algorithm. Further, FIG. 15 is a diagram showing an example of a frame format used for notifying the base station 100 of the subcarrier number specified by using the fourth interleaved algorithm V and its received SIR value. is there. In the fourth decimation algorithm, the flow for detecting the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed is the same as the flow shown in FIG. Description is omitted.

 [0086] In the fourth decimation algorithm, as shown in Fig. 13, in the reception SIR curve, the reception SIR value between adjacent subcarriers is compared, and the subcarrier number when the slope in the reception SIR curve is reversed and its subcarrier number. The received SIR value is extracted, and the received SIR value of the subcarrier arranged in the middle of the extracted subcarrier number is extracted.

[0087] The frame format used for notification to base station 100 includes the subcarrier number extracted as described above, its received SIR value, and subcarriers arranged between these subcarrier numbers. The received SIR value is described. Using the example shown in Figure 13 For example, the 1st, 5th, 18th, 27th ... subcarrier number and its received SIR value, and the 11th subcarrier number arranged between the 5th subcarrier and the 18th subcarrier And the received SIR value, the 22nd subcarrier number arranged between the 18th subcarrier and the 27th subcarrier, and the received SIR value are described and notified to the base station 100. .

 For a specific algorithm, as shown in FIG. 14, the total number k of reverse change points detected in the flow shown in FIG. 11 is calculated (step S61). After initializing the reverse change point s (s = 1) (step S62), it is determined whether the number of subcarriers between the sth reverse change point and the (s + 1) th reverse change point is γ or more. (Step S63).

 [0089] When the number of subcarriers is γ or more, the subcarrier number arranged in the middle of the subcarriers between the sth reverse change point and the (s + 1) th reverse change point is calculated. (Step S64). Then, after extracting the calculated reception SIR value of the intermediate subcarrier (step S65), the reception SIR value is added to the frame format (step S66).

 [0090] Thereafter, after the number of reverse change points s is incremented (s = s + l) (step S67), it is determined whether (s + 1) is larger than the total number k of reverse change points (step S68). If so, exit the fourth algorithm. On the other hand, if it is smaller, the process returns to step S63, and the processes of steps S63 to S68 are repeated. While the processes of step S63 to step S68 are repeated, if it is determined in step S68 that (s + 1) is larger than the total number k of reverse change points, the fourth algorithm ends.

 [0091] If it is determined in step S63 that the number of subcarriers is less than γ, the process proceeds to step S67, and the process of steps S63 to S68 is performed again for the reverse change point (s + 1). To do. That is, when the number of subcarriers between the sth reverse change point and the (s + 1) th reverse change point is less than γ, the subcarriers arranged in the middle are not calculated.

[0092] Here, the subcarrier number of the first reverse change point is “Α”, the subcarrier number of the second reverse change point is “Β”, and the subcarrier number of the third reverse change point is “C”. · · · · Last reversal A specific example when the subcarrier number of the change point is “N” is shown. In this case, as shown in Fig. 15, the subcarrier number at each inversion change point and its received SIR value are Described in the format. Then, in step S64, a subcarrier number arranged between the Ath subcarrier and the Bth subcarrier is calculated. Thereby, {(A + B) Z2} is calculated as the subcarrier number. In step S65, the received SIR value of the {(A + B) Z2} -th subcarrier is extracted, and in step S66, it is added to the frame format. By performing such processing up to the subcarrier at the Nth reverse change point, the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are detected, and the subcarrier number whose slope is reversed. The received SIR value of the subcarrier placed in between is detected and described in the frame format shown in Fig. 15.

 [0093] Thus, when the fourth decimation algorithm is used, the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are detected, and the subcarrier whose slope is reversed is detected. The reception SIR value of the subcarrier arranged in the middle between the numbers is detected and notified to the base station 100 as radio propagation path information. For this reason, it is possible to significantly reduce the amount of radio propagation path information compared to the case of notifying the reception SIR values of all subcarriers, and to improve the transmission efficiency on the link for notifying the propagation path information. In addition, since the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are notified, it is possible to prevent notification of a received SIR value that is significantly different from the actual received SIR value. it can. As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the radio state is selected and communication errors increase, and it is possible to suppress the occurrence of errors during communication. Furthermore, since the reception SIR value of the subcarrier arranged in the middle between the subcarrier numbers whose slopes in the reception SIR curve are reversed is notified, the base station 100 based on this information sets the modulation method 'coding rate. It can be corrected. As a result, it is possible to select a modulation method or the like that is more suitable for the radio state, and it is possible to further suppress the occurrence of errors during communication.

Next, the fifth thinning algorithm will be described. The fifth decimation algorithm detects the subcarrier number and its received SIR value when the slope in the received SIR curve is reversed (decreased from increased calorie or increased decremental power), and the subcarrier number of which the slope is reversed. Detects subcarrier number having received SIR value in the middle between received SIR values It is. By notifying only the detected subcarrier number and its received SIR value to base station 100, the other subcarrier numbers and its received SIR values are thinned out as a result.

 FIG. 16 is a diagram for explaining the outline of the fifth thinning-out algorithm. FIG. 17 is a flowchart for explaining the fifth thinning algorithm. Further, FIG. 18 is a diagram showing an example of a frame format used to notify base station 100 of the subcarrier number specified by using the fifth decimation algorithm V and the received SIR value. In the fifth decimation algorithm, the flow for detecting the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed is the same as the flow shown in FIG. Description is omitted.

 [0096] In the fifth decimation algorithm, as shown in FIG. 16, in the reception SIR curve, the reception SIR values between adjacent subcarriers are compared, and the subcarrier number when the slope in the reception SIR curve is reversed and its subcarrier number. The received SIR value is extracted, and further, the subcarrier number having the received SIR value that is an intermediate value of the extracted received SIR value is extracted.

 [0097] The frame format used for notification to base station 100 includes a subcarrier number extracted as described above, its received SIR value, and a received SIR value that is an intermediate value of these received SIR values. Is described. If the example shown in FIG. 16 is used, the 1st, 5th, 18th, 27th, etc. subcarrier numbers and their received SIR values, as well as the 5th subcarrier received SIR value and the 18th subcarrier received It has a received SIR value that is the intermediate value between the SIR value and the received SIR value that is the intermediate value between the received SIR value of the 18th subcarrier and the received SIR value of the 27th subcarrier. The 21st subcarrier number is described and reported to base station 100

As for a specific algorithm, as shown in FIG. 17, the total number k of reverse change points detected in the flow shown in FIG. 11 is calculated (step S71). After initializing the number of reverse change points s (s = 1) (step S72), it is determined whether the number of subcarriers between the sth reverse change point and the (s + 1) th reverse change point is γ or more. (Step S73).

[0099] When the number of subcarriers is γ or more, the subkey corresponding to the sth reverse change point An intermediate value (becoming reception SIR value) between the reception SIR value of the carrier and the reception SIR value of the subcarrier corresponding to the (s + 1) th reverse change point is calculated (step S74). Then, after extracting the subcarrier number having the calculated intermediate value (step S75), the subcarrier number is added to the frame format (step S76).

 [0100] After that, after the number of reverse change points s is incremented (s = s + l) (step S77), it is determined whether (s + 1) is larger than the total number k of reverse change points (step S78). If so, exit the fifth algorithm. On the other hand, if it is smaller, the process returns to step S73, and the processes of steps S73 to S78 are repeated. While the processes in steps S73 to S78 are repeated, if it is determined in step S78 that (s + 1) is larger than the total number k of reverse change points, the fifth algorithm ends.

 [0101] If it is determined in step S73 that the number of subcarriers is less than γ, the process proceeds to step S77, and the reverse change point (s + 1) is repeated again in steps S73 to S73. Process S78. That is, if the number of subcarriers between the sth reverse change point and the (s + 1) th reverse change point is less than γ, the intermediate value of the received SIR value of the corresponding subcarrier should not be calculated! /.

[0102] Here, the reception SIR value of the subcarrier at the first reverse change point is “A”, the reception SIR value of the subcarrier at the second reverse change point is “B”, and the third reverse change point The subcarrier reception SIR value is “C”, and a specific example in which the reception SIR value of the subcarrier at the last reverse change point is “N” is shown. In this case, as shown in FIG. 18, the subcarrier number of each inversion change point and the received SIR value are described in the frame format. In step S74, an intermediate value between the received SIR value A and the received SIR value B is calculated. As a result, {(A + B) Z2} is calculated as the intermediate value. In step S75, the subcarrier number of the subcarrier having the reception SIR value closest to the intermediate value of {(A + B) Z2} is extracted and added to the frame format in step S76. By performing such processing up to the reception SIR value of the subcarrier at the last reverse change point, the subcarrier number and the reception SIR value when the inclination in the reception SIR curve is reversed are detected, and the inclination is reversed. An intermediate received SIR value between the received subcarrier number received SIR values is detected and described in the frame format shown in Fig.18. [0103] Thus, when the fifth decimation algorithm is used, the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are detected, and the subcarrier whose slope is reversed is detected. The subcarrier number having an intermediate received SIR value between the received SIR values of the number is detected and notified to the base station 100 as radio propagation path information. For this reason, the amount of radio propagation path information can be significantly reduced compared to the case of notifying the reception SIR values of all subcarriers, and the transmission efficiency on the link for notifying the propagation path information can be improved. . In addition, since the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are notified, it is possible to prevent the received SIR value from being significantly different from the actual received SIR value. . As a result, it is possible to avoid a situation in which a modulation scheme or the like that does not conform to the radio state is selected and communication errors increase, and it is possible to suppress the occurrence of errors during communication. Furthermore, since the subcarrier number having the reception SIR value intermediate between the reception SIR values of the subcarrier numbers whose slope in the reception SIR curve is reversed is notified, the base station 100 uses this information to modulate the modulation scheme. The sign rate can be modified. As a result, it is possible to select a modulation method or the like that is more suitable for the radio state, and it is possible to further suppress the occurrence of errors during communication.

 [0104] As described above, the first to fifth decimation algorithms described above can be used by switching according to, for example, the state of error in the radio propagation path. When the decimation algorithm is used by switching, it is necessary for the base station 100 and the mobile station 200 to recognize the selected decimation algorithm in common. The following describes the case where the received SIR information is reported by switching the thinning algorithm.

 [0105] In this case, a common table in which each thinning algorithm is registered in advance is maintained between the base station 100 and the mobile station 200, and a timing for notifying the selected thinning algorithm is negotiated. It is possible to realize it. As the timing for notifying the selected thinning algorithm, for example, timing before starting data communication is assumed.

FIG. 19 is a diagram showing an example of a common table held in advance by the base station 100 and the mobile station 200. In the table shown in FIG. 19, notification numbers corresponding to the first to fifth decimation algorithms are registered. Such a table is held in the base station 100 and the mobile station 200, and the selected thinning algorithm is shown in a frame format as shown in FIG. It is possible to share the common recognition algorithm selected by transmitting it to the base station 100 by describing it in the network.

 [0107] In the frame format shown in Fig. 20, a frame describing the number of the thinning algorithm (algorithm number) and the received SIR information shown in Figs. 5, 8, 12, 15, and 18 are described. And a frame. The base station 100 can recognize the thinning algorithm selected by the mobile station 200 by reading out the algorithm number described in such a frame format and reading out the received SIR information.

 [0108] In the communication system according to the present embodiment, a thinning algorithm is selected according to the error situation in the radio propagation path. The method for determining the error in the radio propagation path is not particularly limited. For example, the actual received SIR value measured by the mobile station 200 for each m and the received SIR value of each m subcarrier calculated by each decimation algorithm are compared, and the decimation algorithm is the smallest. The received SIR value of the subcarrier randomly selected by the mobile station 200 may be compared with the received SIR value of the corresponding subcarrier calculated by each decimation algorithm, and the thinning out with the smallest error. An algorithm may be selected. It should be noted that, when the same error is detected in different thinning algorithms, it is preferable as an embodiment to select a thinning algorithm with a small amount of radio propagation information to be notified to the base station 100.

 [0109] As described above, when the first to fifth decimation algorithms are switched and used, the most appropriate interleaving algorithm is selected according to the state of the radio propagation path to obtain the radio propagation path information as a base. The station 100 can be notified. In particular, when notifying the radio propagation path information by selecting a decimation algorithm according to the error situation in the radio propagation path, the selection of the modulation method and coding rate is conventionally performed while reducing the amount of radio transmission path information. Therefore, it is possible to improve the transmission efficiency.

 [0110] As described above, according to the radio communication system according to the present embodiment, radio propagation path information in which the received SIR value of a specific subcarrier is thinned out by SIR 210 of mobile station 200 is created. Compared with the case where the received SIR value of the subcarrier is notified to the base station 100, it is possible to improve the transmission efficiency on the link for notifying the propagation path information.

[0111] In the above description, the case where the radio propagation path information is generated based on the received SIR. The present invention is not limited to this, but is not limited to reception SNR (signal power to noise power ratio) or reception SINR (signal power to interference noise power ratio: signal to noise power ratio). Based on the Interference Plus Noise Power Ratio), radio propagation path information may be generated.

 [0112] In the above description, the power describing the embodiment in the downlink from the base station 100 to the mobile station 200. The present invention is not limited to this. It is also possible to adapt to the uplink to Also in this case, it is possible to obtain the same effect as in the present embodiment.

 [0113] Further, in the above description, a radio communication system that performs high-speed communication by adaptively changing the modulation scheme, coding rate, etc. for each subcarrier based on the radio propagation path state on the receiver side. The Power Explained The present invention is not limited to this, but can also be applied to a radio communication system that performs high-speed communication by allocating subcarriers with good radio channel conditions to users based on radio channel conditions. It is.

 Brief Description of Drawings

 FIG. 1 is a block diagram showing a configuration of a base station constituting a radio communication system according to the present invention.

 FIG. 2 is a block diagram showing a configuration of a mobile station constituting the wireless communication system according to the present invention.

 FIG. 3 is a diagram for explaining an outline of a first thinning algorithm.

 FIG. 4 is a flowchart for explaining a first thinning-out algorithm.

 FIG. 5 is a diagram showing an example of a frame format used for notifying a base station of a reception SIR value of a subcarrier identified using a first thinning algorithm.

 FIG. 6 is a diagram for explaining an outline of a second thinning algorithm.

 FIG. 7 is a flowchart for explaining a second thinning algorithm.

 FIG. 8 is a diagram showing an example of a frame format used for notifying a base station of a reception SIR value of a subcarrier specified using a second thinning algorithm.

FIG. 9 is a diagram showing an example of a table of threshold values with respect to the slope of the received SIR curve in the second thinning algorithm. FIG. 10 is a diagram for explaining an outline of a third thinning algorithm.

 FIG. 11 is a flowchart for explaining a third thinning algorithm.

 FIG. 12 is a diagram showing an example of a frame format used for notifying a base station of a reception SIR value of a subcarrier specified using a third thinning algorithm.

 FIG. 13 is a diagram for explaining an outline of a fourth inter-bow I-cut algorithm.

 FIG. 14 is a flowchart for explaining a fourth thinning algorithm.

 FIG. 15 is a diagram showing an example of a frame format used for notifying a base station of a reception SIR value of a subcarrier specified using a fourth thinning algorithm.

 FIG. 16 is a diagram for explaining the outline of a fifth thinning algorithm.

 FIG. 17 is a flowchart for explaining a fifth thinning-out algorithm.

 FIG. 18 is a diagram showing an example of a frame format used for notifying a base station of a reception SIR value of a subcarrier specified using a fifth thinning algorithm.

 FIG. 19 is a diagram showing an example of a common table held in advance by the base station and the mobile station.

 FIG. 20 is a diagram showing an example of a frame format for notifying the base station of the thinning algorithm selected by the mobile station.

 FIG. 21 is a diagram illustrating an example of transmission power at the time of transmission with a base station power.

 FIG. 22 is a diagram showing an example of a received signal of a mobile station when affected by frequency forging.

 FIG. 23 is a diagram showing an example of a communication scheme for determining a modulation scheme 'code rate based on a reception SIR of a mobile station.

 FIG. 24 is a diagram for explaining a conventional method of notifying propagation path information.

 FIG. 25 is a diagram for explaining an example of a modulation scheme selected from a conventional method of notifying propagation path information.

Explanation of symbols

100 Base station equipment (Base station)

108 Uplink reception processor

109 SIR information extraction unit 200 Mobile station equipment (mobile station) 207 SIR estimation unit

210 SIR Information Creation Department

Claims

The scope of the claims  [1] A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner,  A propagation path information creation section for creating propagation path information with a value indicating a propagation path situation of a specific subcarrier according to an estimation result by the propagation path situation estimation section;  A wireless transmitter comprising: a transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner.  [2] The propagation path information creation unit is linearly interpolated from a value indicating a propagation path condition for a subcarrier selected for each predetermined number and a value value indicating a propagation path condition for the selected adjacent subcarrier. 2. The radio transmitter according to claim 1, wherein propagation path information is created only from a subcarrier number having a value indicating the propagation path condition having the largest error and a value indicating the propagation path condition.  [3] The propagation path information creation unit determines the subcarrier number when the slope of the curve obtained by connecting the values indicating the propagation path condition for each subcarrier changes by a predetermined value or more and the propagation path condition. 3. The radio transmitter according to claim 1, wherein propagation path information is created only from a value indicating  [4] The propagation path information creation unit includes a subcarrier number and a value indicating the propagation path condition when the sign of the slope of the curve obtained by connecting the value indicating the propagation path condition for each subcarrier is changed. The radio transmitter according to any one of claims 1 to 3, wherein the propagation path information is created only from the above.  [5] The propagation path information creation unit includes a subcarrier number and a value indicating the propagation path condition when the sign of the slope of the curve obtained by connecting a value indicating the propagation path condition for each subcarrier is changed. 5. The propagation path information is created only from values indicating propagation path conditions for subcarriers arranged in the middle between the subcarrier numbers in which the sign of the slope of the curve has changed. The wireless transmitter according to any one of the above. [6] The propagation path information creation unit includes a subcarrier number and a value indicating the propagation path condition when the sign of the slope of the curve obtained by connecting a value indicating the propagation path condition for each subcarrier is changed. , Between the subcarrier numbers where the sign of the slope of the curve has changed 6. The radio transmitter according to claim 1, wherein the propagation path information is created only from a subcarrier number having a value indicating a propagation path condition. 7. The radio transmitter according to claim 6, wherein the propagation path information creating unit creates the propagation path information by selecting a method with the smallest data amount of the propagation path information. 8. The radio transmitter according to claim 1, wherein the propagation path state estimation unit estimates a signal power to interference power ratio as a propagation path state. [9] The radio transmitter according to any one of claims 1 to 7, wherein the propagation path state estimation unit estimates a signal power to noise power ratio as a propagation path state. 10. The radio transmitter according to claim 1, wherein the propagation path condition estimation unit estimates a signal power to interference noise power ratio as a propagation path condition. [11] A mobile station apparatus comprising the radio transmitter according to any one of claims 1 to 10.  [12] A base station apparatus comprising the radio transmitter according to any one of claims 1 to 10.  [13] A modulation scheme and a code rate are determined for each subcarrier using the mobile station apparatus according to any one of claims 8 to 10 and propagation path information received from the mobile station apparatus. A wireless communication system comprising: a base station device.