JP4960230B2 - Radio transmitter and radio communication system - Google Patents

Description

  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 propagation path state on a receiver side, and a radio communication system including the radio transmitter.

  Currently, in high-speed mobile communication, depending on the state of 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”). Control modulation method and coding rate (MCS: Modulation and Code Scheme) to improve transmission efficiency, adaptive modulation method that provides high-throughput communication, and good radio channel condition from radio channel condition for each user Research and development of an OFDMA system in which a high-speed communication is performed by assigning a subcarrier to each user has been conducted.

  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, the base station can Therefore, it is necessary to grasp the status of received power for each subcarrier received by the mobile station in order to change the modulation scheme and coding rate, or to assign subcarriers with good radio channel conditions to users. On the other hand, the mobile station measures radio propagation path conditions such as received SIR (Signal to Interference Power Ratio) and digitizes the received SIR information of all subcarriers measured by the mobile station. Is transmitted to the base station side.

  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 reception SIR of all subcarriers from the known signal (pilot signal) included in the frame, digitizes the calculated reception SIR information of all subcarriers, and periodically transmits it to the base station side. From the received SIR information received by the mobile station, the base station determines the modulation method and coding rate for each subcarrier based on the threshold value set as shown in FIG. 23, for example, and transmits data to the mobile station .

In addition, when the reception SIR information of all subcarriers measured by the mobile station is transmitted to the base station side, in order to reduce the amount of information, as shown in FIG. There has been proposed a method of calculating an average value of received SIRs of subcarriers in each block and notifying the average value of each block to the base station (for example, see Non-Patent Document 1).
Yokomakura Kazunari, Sampei Seiichi, Morinaga Norihiko, “Study on Interference Power Estimation and Notification Technology in 1-cell Repetitive OFDM / TDMA System Using Adaptive Modulation”, IEICE Technical Report RCS2003-240 p. 33-38, 2003

  However, since the information amount of radio propagation path such as conventional reception SIR is allocated several bits per subcarrier, the information amount of reception SIR increases according to the number of subcarriers. There's a problem. At present, many of the communication systems of the adaptive modulation scheme that are considered use hundreds of subcarriers. Therefore, in order to transmit reception SIRs corresponding to the number of subcarriers, a radio of several kilobits is required. The amount of propagation information is required. In addition, since the modulation scheme is periodically changed in the adaptive modulation scheme, the mobile station must periodically notify the base station of the propagation path information in accordance with the cycle of the base station. For this reason, in the uplink, the usage rate of the information amount of the propagation path information is large, and the transmission efficiency is poor. Further, in such a communication system, the transmission rate of the uplink from the mobile station to the base station is assumed to be a communication system having a lower transmission rate than that of the downlink from the base station to the mobile station. It is a cause of further worsening.

  Further, in the method disclosed in Non-Patent Document 1, there are subcarriers with good radio conditions and bad subcarriers within the blocked subcarrier group. For this reason, 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, radio conditions are poor. There is a problem that a modulation scheme having a high modulation degree is selected for a subcarrier and an error increases, and an optimal modulation scheme is not selected for the subcarrier, resulting in a decrease in transmission efficiency.

  The present invention has been made in view of such conventional problems, and is capable of improving transmission efficiency on a link for notifying propagation path information while suppressing the occurrence of errors during communication. It is an object of the present invention to provide a transmitter and a wireless communication system including the transmitter.

  (1) In order to achieve the above object, the present invention has taken 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 a propagation path state, 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 a feature.

  In this way, since the propagation path information creation unit creates propagation path information obtained by thinning out the value indicating the propagation path condition of a specific subcarrier, compared to the case where the value indicating the propagation path condition of all subcarriers is notified. It becomes possible to improve the transmission efficiency on the link for notifying the propagation path information.

  (2) Further, in the wireless transmitter according to the present invention, the propagation path information creation unit includes a value indicating a propagation path condition for a subcarrier selected for each predetermined number and a propagation for the selected adjacent subcarrier. Propagation path information is created only from a value obtained by linear interpolation from a value indicating a path condition, a subcarrier number having a value indicating a propagation path condition having the largest error, and a value indicating the propagation path condition.

  As described above, the propagation path having the largest error between the value indicating the propagation path condition for the subcarrier selected for each predetermined number and the value obtained by linear interpolation from the value indicating the propagation path condition for the selected adjacent subcarrier. Since the propagation path information is created only from the subcarrier number having a value indicating the status and the value indicating the propagation path status, the propagation path information is compared with the case of notifying the value indicating the propagation path status of all the subcarriers. The transmission efficiency on the link that notifies In addition, since the subcarrier number with the largest error and the value indicating the propagation path condition are notified, for example, the modulation scheme and coding rate can be corrected based on such information at the communication partner. 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.

  (3) Further, in the wireless transmitter according to the present invention, the propagation path information creation unit changes a slope of a curve obtained by connecting values indicating propagation path conditions for each subcarrier by a predetermined value or more. In this case, propagation path information is created only from the subcarrier number of the case and the value indicating the propagation path condition.

  In this way, the propagation path is determined only from the subcarrier number and the value indicating the propagation path condition when the slope of the curve obtained by connecting the propagation path value for each subcarrier changes by a predetermined value or more. Since the information is created, the amount of radio channel information can be significantly reduced compared to the case of reporting values indicating the channel conditions of all subcarriers, and the transmission efficiency on the link that reports channel information 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 it is possible to suppress the occurrence of errors during communication.

  (4) Further, in the wireless transmitter according to the present invention, the propagation path information creation unit is a subcarrier when the sign of the slope of the curve obtained by connecting the values indicating the propagation path conditions for each subcarrier changes. Propagation path information is created only from a number and a value indicating the propagation path status.

  In this way, propagation path information is created only from the subcarrier number and the value indicating the propagation path condition when the sign of the slope of the curve obtained by linking the value indicating the propagation path condition for each subcarrier changes. Therefore, the amount of radio channel information can be significantly reduced compared to the case of reporting values indicating the channel conditions of all subcarriers, and the transmission efficiency on the link for reporting channel information can be improved. Can do. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope in the 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 it is possible to suppress the occurrence of errors during communication.

  (5) Further, in the radio transmitter according to the present invention, the propagation path information creation unit is a subcarrier when the sign of the slope of the curve obtained by connecting values indicating the propagation path conditions for each subcarrier changes. Propagation path information is created from only a number and a value indicating the propagation path condition, and a value indicating the propagation path condition for a subcarrier arranged in the middle between the subcarrier numbers whose sign of the curve changes. It is said.

  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 and the value indicating the propagation path condition, and the sign of the slope of the curve are Because propagation path information is created only from the value indicating the propagation path condition for the subcarriers arranged in the middle between the changed subcarrier numbers, compared to the case of notifying the value indicating the propagation path condition of all subcarriers The amount of radio propagation path information can be greatly reduced, and the transmission efficiency on the link that notifies the propagation path information can be improved. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope in the 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 it is possible to suppress the occurrence of errors during communication. Further, since a value indicating the propagation path condition of the subcarriers arranged in the middle between the subcarrier numbers whose slopes in the above curve are reversed is notified, for example, the modulation scheme / code at the communication partner based on such information The conversion rate can be corrected. As a result, it is possible to select a modulation method or the like that is more suitable for the wireless state, and thus it is possible to further suppress the occurrence of errors during communication.

  (6) Moreover, in the wireless transmitter according to the present invention, the propagation path information creation unit is a subcarrier when a sign of a slope of a curve obtained by connecting a value indicating a propagation path state for each subcarrier is changed. Propagation path information is created only from a subcarrier number having a value indicating a propagation path condition intermediate between a number and a value indicating the propagation path condition and a subcarrier number whose sign of the curve has changed. Yes.

  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 and the value indicating the propagation path condition, and the sign of the slope of the curve are Since propagation path information is created only from the subcarrier number having a value indicating the intermediate propagation path condition between the changed subcarrier numbers, it is significantly larger than when reporting the propagation path condition values of all subcarriers. In addition, the amount of radio propagation path information can be reduced, and the transmission efficiency on the link for notifying the propagation path information can be improved. In addition, since the subcarrier number and the value indicating the propagation path condition when the slope in the 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 it is possible to suppress the occurrence of errors during communication. Further, since the subcarrier number having a value indicating the intermediate propagation path condition between the values indicating the propagation path condition of the subcarrier number whose slope in the above curve is reversed is notified, the communication partner is based on these information. For example, the modulation scheme / coding rate can be corrected. As a result, it is possible to select a modulation method or the like that is more suitable for the wireless state, and thus it is possible to further suppress the occurrence of errors during communication.

  (7) In the wireless transmitter according to the present invention, 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. .

  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 select the method that can improve the transmission efficiency most. The channel information can be notified to the communication partner.

  (8) Further, in the radio transmitter according to the present invention, the propagation path state estimation unit estimates a received SIR (Signal to Interference Power Ratio) as a propagation path state. .

  (9) Further, in the radio transmitter according to the present invention, the propagation path state estimation unit estimates a received SNR (Signal to Noise Power Ratio) as a propagation path state. .

  (10) In the radio transmitter according to the present invention, the propagation path state estimation unit estimates a reception SINR (Signal to Interference Plus Noise Power Ratio) as a propagation path state. It is a feature.

  As described above, since the propagation path state estimation unit estimates the reception SIR, the reception SNR, and the reception SINR as the propagation path state, the propagation path state can be estimated appropriately.

  (11) Further, a mobile station apparatus according to the present invention includes the wireless transmitter according to any one of claims 1 to 10.

  As described above, since the mobile station apparatus includes the wireless transmitter, the transmission efficiency on the link for notifying the propagation path information is improved as compared with the case of notifying the value indicating the propagation path condition of all subcarriers. In addition, the mobile station apparatus can obtain the effects obtained by the wireless transmitter according to each claim.

  (12) In addition, a base station apparatus according to the present invention includes the wireless transmitter according to any one of claims 1 to 10.

  As described above, since the base station apparatus includes the wireless transmitter, the transmission efficiency on the link for notifying the propagation path information is improved as compared with the case of notifying the value indicating the propagation path condition of all the subcarriers. In addition, the base station apparatus can obtain the effects obtained by the wireless transmitter according to each claim.

  (13) Moreover, the radio communication system according to the present invention provides, 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. And a base station device that determines a modulation scheme and a coding rate.

  As described above, since the wireless communication system includes the mobile station apparatus according to any one of claims 8 to 10, in the wireless communication system, a value indicating a propagation path condition of all subcarriers is notified. In comparison, it is possible to improve the transmission efficiency on the link for notifying the propagation path information.

  According to the wireless transmitter and the wireless communication system according to the present invention, it is possible to improve transmission efficiency on a link for notifying propagation path information while suppressing occurrence of errors during communication.

  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 a radio communication system according to an 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 at a coding rate instructed from an MCS allocation section described later. Encode data. The data modulation unit 102 performs modulation processing on the encoded data from the encoding unit 101 according to a modulation scheme instructed by an MCS allocation unit described later. A serial / parallel conversion unit (S / P conversion unit) 103 performs serial / parallel conversion on the modulation data from the data modulation unit 102 and converts it into modulation data that has been processed in parallel according to the number of subcarriers.

  Multiplexing section (Mux section) 104 uses modulated data converted in parallel to the number of subcarriers, a pilot signal for mobile station 200 to estimate the received SIR, and a modulation scheme for each subcarrier from MLI generation section 111 described later. Then, it is multiplexed with modulation / coding information (MLI: Multilevel Information) in which the coding rate is described. A pilot signal used for multiplexing is delivered from pilot generation section 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 to convert it into an OFDM signal. The radio transmission unit 107 up-converts the OFDM signal to a radio frequency band, and transmits the sub-carrier to each mobile station with a constant transmission power.

  The uplink reception processing unit 108 receives data from the mobile station 200 and separates the received data from the 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 the base station 100 does not necessarily have to have adaptive modulation reception capability.

  The SIR information extraction unit 109 extracts the thinning information including the subcarrier number and SIR value transmitted from the mobile station 200 from the reception SIR information received from the uplink reception processing unit 108. Further, the SIR value of the subcarrier thinned out on the mobile station 200 side is calculated by linearly interpolating between specific received SIR values from the thinning information. Further, the reception SIR values of all subcarriers are sent to MCS allocation section 110.

  The MCS allocating unit 110 determines the MCS of each subcarrier from the calculated SIR value of each subcarrier, and instructs the coding unit 101 and the data modulation unit 102 to specify the coding rate and the modulation scheme, respectively. 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 with a modulation scheme and a coding rate that the mobile station 200 can receive in any environment, and passes the generated MLI to the Mux unit 104.

  The modulation scheme and coding rate performed by MLI generation section 111 are determined in advance between base station 100 and mobile station 200, and the scheme and the like are fixed. Also, since the MLI must be able to be received under any environment, it is desirable that the modulation multi-level number is as low as possible (such as BPSK or QPSK) and the coding rate is low.

  On the other hand, in the mobile station 200 shown in FIG. 2, the radio reception unit 201 receives a radio signal from the 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 a Fourier transform and returns the OFDM signal to modulated data. The DeMux unit 203 separates the multiplexed modulation data, and sends the modulation data to the parallel / serial conversion unit (P / S conversion unit) 204, the MLI to the MLI extraction unit 206, and the pilot signal to the SIR estimation unit 207.

  A parallel / serial conversion unit (P / S conversion unit) 204 performs parallel / serial conversion on the modulation data processed in parallel to the number of subcarriers, returns the modulation data to one column, and sends the data to the data demodulation unit 205. The data demodulating unit 205 demodulates the modulated data according to a demodulation method instructed according to an instruction from the MCS control unit 209 described later, and returns the encoded data to encoded data. The decoding unit 208 decodes the encoded data by a method instructed according to an instruction from the MCS control unit 209 described later, and restores the original data.

  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 controls the data demodulation unit 205 and the decoding unit 208.

  SIR estimation section 207 estimates the reception SIR of each subcarrier from the pilot signal. At this time, the estimated received SIR is a 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 using a thinning algorithm described later, and passes it to the uplink transmission processing unit 211. The uplink transmission processing unit 211 multiplexes the SIR information and the transmission data, and transmits them to the base station 100 as a radio signal.

  Note that, regarding the uplink 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.

  In the communication system according to the present embodiment, when receiving SIR information of all subcarriers measured by mobile station 100 is transmitted to base station 100, the amount of information is obtained by thinning out the received SIR values of specific subcarriers. And avoiding a decrease in transmission efficiency and an increase in errors during communication, which may occur by notifying the reception SIR values of all subcarriers. Hereinafter, an algorithm (hereinafter referred to as a “thinning algorithm”) used when thinning received SIR values in a specific subcarrier will be described.

  The thinning algorithm described above is used when the SIR information creation unit 210 in the mobile station 200 creates SIR information that is transmitted to the base station 100. The SIR information creation unit 210 can use the thinning algorithm shown below alone, or can use it by switching depending on the situation such as an error in the radio propagation path. Hereinafter, first to fifth thinning algorithms used in the SIR information creation unit 210 will be described.

  First, the first thinning algorithm will be described. The first decimation algorithm calculates the subcarrier number and received SIR value having 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 to detect. Only the received SIR values of the detected subcarrier number subcarriers and every m subcarriers are notified to the base station 100, and the received SIR values of the 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. Furthermore, FIG. 5 is a diagram illustrating an example of a frame format used for notifying the base station 100 of the reception SIR value of the subcarrier specified using the first thinning algorithm.

  In the first thinning algorithm, as shown in FIG. 3, after extracting the reception SIR values of every m carriers (every 10 in FIG. 3), linear interpolation is performed between the reception SIR values (linear interpolation). Values are shown as 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.

  In the frame format used for notification to the base station 100, a reception SIR value of each of m subcarriers, a subcarrier number and a reception SIR value that are the maximum error between m, are described. If the example shown in FIG. 3 is used, between the 1st and 11th subcarriers, the 5th subcarrier number and its subcarrier number and its received SIR value have the largest error from the actual received SIR value. The received SIR value is notified.

  As for a specific algorithm, as shown in FIG. 4, first, the reference number i is initialized (i = 0) (step S1), and the received SIR value of the first subcarrier is added to the frame format (step S1). Step S2).

  Next, it is determined whether (m * (i + 1) +1) exceeds the total number n of subcarriers (step S3). If it is lower, the reference number i is incremented (step S4), and steps S2 to S2 are performed. The process of S4 is 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 subcarrier when the reference number i indicates “2”. The SIR value of the carrier is added to the format. Similarly, every m SIR values up to the nth subcarrier are added to the format.

  On the other hand, if the result of determination in step S3 is greater, after the reference number i is initialized (i = 0) (step S5), the received SIR value of the (m * i + 1) th subcarrier is , A slope d with the received SIR value of the (m * (i + 1) +1) th subcarrier is calculated (step S6).

  Then, after initializing the reference number j (j = 1) and initializing the maximum error h (h = 0) (step S7), the slope d and the received SIR value of the (m * i + 1) th subcarrier And an error g is calculated using the received SIR value of the (m * i + j + 1) th subcarrier (step S8). Here, the SIR value of the second subcarrier interpolated from the reception SIR value of the first subcarrier and the reception SIR value of the second subcarrier is obtained, and the SIR value of the second subcarrier obtained by interpolation is calculated. The error g of the actual reception SIR value is calculated.

  It is determined whether the error g calculated in step S8 is larger than the maximum error h (step S9). If it is large, the error g calculated in step S8 is substituted for the maximum error h (h = g), and the target subcarrier is determined. The 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.

  Then, it is determined whether 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 exceeds m (step S11). If the determination result in step S11 does not exceed, the reference number j is incremented (j = j + 1) (step S12), and then the processes in steps S7 to S12 are repeated.

  By repeating the processes in steps S7 to 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. On the other hand, if the error g is smaller than the maximum error h, the error g of the fourth subcarrier is calculated. Compare with The above processing is repeated up to the m-th subcarrier, and the subcarrier number and SIR value that are 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 subcarrier total number n (step S15).

  If not, the process returns to step S7, and this time 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. Then, the above processing is repeated until the nth subcarrier, and the subcarrier number and the received SIR value that are the maximum error h in each section are detected and described in the frame format shown in FIG.

  As described above, when the first thinning algorithm is used, the reception SIR value of the subcarrier for each predetermined number (m) and the subcarrier number having the largest error from the actual reception SIR value and the reception thereof. The SIR value is detected and notified to the base station 100 as radio propagation path information. For this reason, it is possible to improve the transmission efficiency on the link for notifying the propagation path information as compared with the case of notifying the reception SIR values of all subcarriers. Further, since the subcarrier number having the largest error from the actual received SIR value and the received SIR value are notified, the base station 100 can correct the modulation scheme and coding rate based on such information. 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 second thinning algorithm will be described. The second thinning algorithm detects a subcarrier number and its received SIR value when the slope of a curve obtained by connecting received SIR values (hereinafter referred to as “received SIR curve”) changes by a certain value or more. To do. Only the subcarrier of the detected subcarrier number and its received SIR value are notified to the base station 100, and 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. Furthermore, FIG. 8 is a diagram illustrating an example of a frame format used for notifying the base station 100 of the reception SIR value of the subcarrier specified using the second thinning algorithm.

  In the second decimation algorithm, as shown in FIG. 6, in the reception SIR curve, the slope of the reception SIR value between the subcarriers is calculated, and the slope between the subcarriers to be calculated is between the reference subcarriers. A subcarrier number and a received SIR value when the inclination changes by a certain value or more are extracted.

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

  As for a 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 are converted into a frame format. It adds (step S22). After the reference number j is initialized (j = 1) (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, the threshold value (lower threshold value Pmin, upper threshold value Pmax) corresponding to the calculated slope A is searched from the preset threshold value table shown in FIG. 9 (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.

  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 reception SIR value of the (t + j−1) th subcarrier and the reception SIR value of the (t + j) th subcarrier is calculated (step S30). Then, it is determined whether any 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).

  If both the slope B and the slope C are values between the threshold value Pmin and the threshold value 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 steps S27 to S31 are performed. Repeat the process. On the other hand, when one of the slope B and the slope C is a value other than the value between the threshold value Pmin and the threshold value Pmax, it is determined that there is a large change in the reception SIR curve, and the subcarrier number t is set to (t + j−1). ) Is substituted (step S32), and the process returns to step S22. And the process of step S22-step S32 is repeated.

  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 subcarrier total number n, the subcarrier number (t + j) th subcarrier number and its reception SIR The value is added to the frame format (step S33), and the second thinning algorithm is terminated.

  Here, a specific example when 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 received SIR value of the first subcarrier and the received SIR value of the second subcarrier, in step S26, a threshold value corresponding to the slope A (lower threshold Pmin, The upper limit threshold value Pmax) is searched. Then, after calculating the slope B between the reception SIR value of the first subcarrier and the reception SIR value of the third subcarrier in step S29, in step S30, the reception SIR value of the second subcarrier, A slope C with respect to the reception SIR value of the third subcarrier is calculated. In step S31, it is determined whether the slope B or C is a value other than the value between the lower threshold Pmin and the upper threshold Pmax, thereby determining the slope change point. That is, when 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, the change point of the slope 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.

  As described above, 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 100 receives the radio propagation path information as radio propagation path information. Notice. For this reason, compared with the case where the reception SIR values of all subcarriers are notified, the amount of radio propagation path information can be significantly reduced, and the transmission efficiency on the link for reporting the propagation path information can be improved. Further, 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 notified, it is possible to prevent the received SIR value from being significantly deviated 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 radio state is selected and communication errors increase, and it is possible to suppress the occurrence of errors during communication.

  Next, the third thinning algorithm will be described. The third decimation algorithm detects the subcarrier number and the received SIR value when the slope in the received SIR curve is reversed (decrease from increase or increase from decrease). Notifying only the detected subcarrier number and its received SIR value to the base station 100 results in thinning out the other subcarrier numbers and its received SIR value 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. Furthermore, FIG. 12 is a diagram illustrating an example of a frame format used for notifying the base station 100 of the reception SIR value of the subcarrier specified using the third thinning algorithm.

  In the third thinning 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 the reception SIR value when the slope in the reception SIR curve is reversed are obtained. Extract.

  The frame format used for notification to the base station 100 describes the subcarrier number extracted as described above and its received SIR value. If the example shown in FIG. 10 is used, the 1st, 5th, 10th... Subcarrier numbers and the received SIR values are described and notified to the 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 converted into a frame format. It adds (step S42). Then, after initializing the reference number j (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.

  On the other hand, if the determination in step S44 is not the same, the difference α 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 determined again whether the number of subcarriers indicated by (t + j) is the same as the total number of subcarriers n (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, a difference β 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 α is 0 or more and α is larger than β, or whether the difference α is less than 0 and α is smaller than β (step S49). If none of these are true, it is determined that there is no reversal of the slope in the received SIR curve, and after substituting the difference β into the difference α (α = β) (step S50), the process returns to step S46. And the process of step S46-step S50 is repeated.

  On the other hand, if applicable, it is determined that there is a reversal of the slope in the received SIR curve, and (t + j-1) is substituted for subcarrier number t (step S51), and then the process returns to step S42. And the process of step S42-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 and its reception SIR The value is added to the frame format (step S52), and the third thinning algorithm is terminated.

  Here, a specific example when 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 α 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 β between the reception SIR value of the first subcarrier and the reception SIR value of the third subcarrier is calculated. In step S49, reception is performed by determining the magnitude relationship between the difference α and the difference β when the difference α is 0 or more, or the magnitude relationship between the difference α and the difference β when the difference α is less than 0. A change point at which the slope in the SIR curve reverses (hereinafter referred to as “reverse change point”) is determined. That is, when the difference α is greater than or equal to 0 and the difference α is greater than the difference β, it is determined that the second subcarrier is the reverse change point, whereas when the difference α is less than 0, the difference α is the difference β. If smaller, the second subcarrier 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 subcarrier number and the received SIR value when the slope in the received SIR curve is reversed are detected and described in the frame format shown in FIG.

  As described above, when the third thinning algorithm is used, the subcarrier number and the reception SIR value when the slope in the reception SIR curve is reversed are detected and notified to the base station 100 as radio propagation path information. For this reason, compared with the case where the reception SIR values of all subcarriers are notified, the amount of radio propagation path information can be significantly reduced, and the transmission efficiency on the link for reporting the propagation path information can be improved. Further, since the subcarrier number and the reception SIR value when the slope in the reception SIR curve is reversed are notified, it is possible to prevent the reception SIR value that is significantly different from the actual reception SIR value 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 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 the received SIR value when the slope in the received SIR curve is reversed (decrease from increase or increase from decrease), and is intermediate between the subcarrier numbers whose slope is reversed. The reception SIR value of the subcarrier arranged in the is detected. Notifying only the detected subcarrier number and its received SIR value to the base station 100 results in thinning out the other subcarrier numbers and its received SIR value 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 illustrating an example of a frame format used for notifying the base station 100 of the subcarrier number specified using the fourth thinning algorithm and the received SIR value. 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. To do.

  In the fourth thinning algorithm, as shown in FIG. 13, in the reception SIR curve, the reception SIR values between adjacent subcarriers are compared, and the subcarrier number and the reception SIR value when the slope in the reception SIR curve is reversed. And the reception SIR value of the subcarrier arranged in the middle of the extracted subcarrier number is extracted.

  The frame format used for notification to the base station 100 includes the subcarrier number extracted as described above and its reception SIR value, and the reception SIR of the subcarrier arranged between these subcarrier numbers. A value is described. If the example shown in FIG. 13 is used, it is arrange | positioned in the middle of the 1st, 5th, 18th, 27th ... subcarrier number and its received SIR value, and the 5th subcarrier and the 18th subcarrier. 11th subcarrier number and its received SIR value, 22nd subcarrier number arranged between the 18th subcarrier and 27th subcarrier, and its received SIR value are described. You will be notified.

  As 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). Then, after the number of reverse change points s is initialized (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).

  If the number of subcarriers is γ or more, a 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).

  Thereafter, after the number of reverse change points s is incremented (s = s + 1) (step S67), it is determined whether (s + 1) is larger than the total number k of reverse change points (step S68). If larger, the fourth algorithm is terminated. 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 in steps S63 to 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.

  If it is determined in step S63 that the number of subcarriers is less than γ, the process proceeds to step S67, and the processes in steps S63 to S68 are performed again for the reverse rotation change point (s + 1). 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, calculation of subcarriers arranged in the middle is not performed.

  Here, the subcarrier number of the first reverse change point is “A”, the subcarrier number of the second reverse change point is “B”, the subcarrier number of the third reverse change point is “C”, etc. A specific example in the case where the subcarrier number of the reverse change point is “N” will be described. In this case, as shown in FIG. 15, the subcarrier number of each inversion change point and the received SIR value are described in the frame format. In step S64, a subcarrier number arranged between the Ath subcarrier and the Bth subcarrier is calculated. Thereby, {(A + B) / 2} is calculated as the subcarrier number. In step S65, the reception SIR value of the {(A + B) / 2} -th subcarrier is extracted and added to the frame format in step S66. 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 reception SIR value of the subcarrier arranged in the middle is detected and described in the frame format shown in FIG.

  As described above, when the fourth thinning algorithm is used, the subcarrier number and the received SIR value when the slope in the reception SIR curve is reversed are detected, and the intermediate between the subcarrier numbers whose slope is reversed is detected. The reception SIR values of the subcarriers arranged in are detected and notified to the base station 100 as radio propagation path information. For this reason, compared with the case where the reception SIR values of all subcarriers are notified, the amount of radio propagation path information can be significantly reduced, and the transmission efficiency on the link for reporting the propagation path information can be improved. Further, since the subcarrier number and the reception SIR value when the slope in the reception SIR curve is reversed are notified, it is possible to prevent the reception SIR value that is significantly different from the actual reception SIR value 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 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 corrects the modulation scheme and coding rate based on such information can do. As a result, it is possible to select a modulation method or the like that is more suitable for the wireless state, and thus 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 the reception SIR value when the slope in the reception SIR curve is reversed (decrease from increase or increase from decrease), and the reception SIR of the subcarrier number whose slope is reversed. A subcarrier number having an intermediate received SIR value between values is detected. Notifying only the detected subcarrier number and its received SIR value to the base station 100 results in thinning out the other subcarrier numbers and its received SIR value 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 for notifying the base station 100 of the subcarrier number specified using the fifth thinning algorithm 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. To do.

  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 and the reception SIR value when the slope in the reception SIR curve is reversed. And a subcarrier number having a reception SIR value that is an intermediate value of the extracted reception SIR values.

  The frame format used for notification to base station 100 has 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. A subcarrier number is described. If the example shown in FIG. 16 is used, the 1st, 5th, 18th, 27th ... subcarrier number and its reception SIR value, and the reception SIR value of the 5th subcarrier and reception of the 18th subcarrier will be described. 14th subcarrier number having a reception SIR value that is an intermediate value between the SIR values, and a reception SIR value that is an intermediate value between the reception SIR value of the 18th subcarrier and the reception SIR value of the 27th subcarrier. The 21st subcarrier number is described and notified to the 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). Then, after the number of reverse change points s is initialized (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).

  When the number of subcarriers is γ or more, an intermediate between the reception SIR value of the subcarrier corresponding to the sth reverse change point and the reception SIR value of the subcarrier corresponding to the (s + 1) th reverse change point A value (becoming reception SIR value) 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).

  Thereafter, after the number of reverse change points s is incremented (s = s + 1) (step S77), it is determined whether (s + 1) is larger than the total number k of reverse change points (step S78). If larger, the fifth algorithm is terminated. 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.

  If it is determined in step S73 that the number of subcarriers is less than γ, the process proceeds to step S77, and the processes in steps S73 to S78 are performed again for the reverse change point (s + 1). 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 intermediate value of the reception SIR value of the corresponding subcarrier is not calculated.

  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 subcarrier reception at the third reverse change point is received. A specific example in which the SIR value is “C”... And the received SIR value of the subcarrier at the last reverse change point is “N” will be described. 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. Thereby, {(A + B) / 2} is calculated as an intermediate value. In step S75, the subcarrier number of the subcarrier having the reception SIR value closest to the intermediate value of {(A + B) / 2} 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 SIR values of the subcarrier numbers is detected and described in the frame format shown in FIG.

  Thus, when the fifth decimation algorithm is used, the subcarrier number and the received SIR value when the slope in the reception SIR curve is reversed are detected, and the reception SIR of the subcarrier number whose slope is reversed is detected. A subcarrier number having an intermediate reception SIR value between the values is detected and notified to base station 100 as radio propagation path information. For this reason, compared with the case where the reception SIR values of all subcarriers are notified, the amount of radio propagation path information can be significantly reduced, and the transmission efficiency on the link for reporting the propagation path information can be improved. Further, since the subcarrier number and the reception SIR value when the slope in the reception SIR curve is reversed are notified, it is possible to prevent the reception SIR value that is significantly different from the actual reception SIR value 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 it is possible to suppress the occurrence of errors during communication. Further, since the subcarrier number having a reception SIR value intermediate between the reception SIR values of the subcarrier numbers whose slopes in the reception SIR curve are reversed is notified, the base station 100 modulates and encodes the modulation scheme and coding based on such information. The rate can be corrected. As a result, it is possible to select a modulation method or the like that is more suitable for the wireless state, and thus it is possible to further suppress the occurrence of errors during communication.

  As described above, the first to fifth decimation algorithms described above can be switched and used in accordance with, for example, the error situation in the radio propagation path. When the decimation algorithm is switched and used, it is necessary for the base station 100 and the mobile station 200 to recognize the selected decimation algorithm in common. Hereinafter, a case where the reception SIR information is notified by switching the thinning algorithm will be described.

  In this case, it can be realized by holding a common table in which each thinning algorithm is registered in advance between the base station 100 and the mobile station 200 and determining the timing for notifying the selected thinning algorithm. is there. As timing for notifying the selected thinning algorithm, for example, timing before starting data communication is assumed.

  FIG. 19 is a diagram illustrating 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 thinning algorithms are registered. Such a table is held by the base station 100 and the mobile station 200, and the selected thinning algorithm is described in a frame format as shown in FIG. 20 and transmitted to the base station 100. Recognition is possible.

  The frame format shown in FIG. 20 includes a frame that describes the number of the thinning algorithm (algorithm number) and a frame that describes the received SIR information shown in FIGS. 5, 8, 12, 15, and 18. ing. The base station 100 can recognize the thinning algorithm selected by the mobile station 200 by reading the algorithm number described in such a frame format and reading the received SIR information.

  In the communication system according to the present embodiment, a thinning algorithm is selected according to the error situation in the radio propagation path. An error determination method in the radio propagation path is not particularly limited. For example, by comparing the actual received SIR value for each m measured by the mobile station 200 and the received SIR value for each m subcarriers calculated by each decimation algorithm, the decimation algorithm with the smallest error is selected. Alternatively, the reception SIR value of the subcarrier randomly selected by the mobile station 200 and the reception SIR value of the corresponding subcarrier calculated by each thinning algorithm are compared, and the thinning algorithm with the smallest error is selected. You may do it. Note that 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 when the same error is detected in different thinning algorithms.

  As described above, when the first to fifth decimation algorithms are switched and used, the most appropriate decimation algorithm is selected according to the state of the radio propagation path and the radio propagation path information is notified to the base station 100. Is possible. In particular, when radio channel information is notified by selecting a decimation algorithm according to the error situation in the radio channel, the selection of the modulation method and coding rate can be performed while reducing the amount of radio channel information. It can be performed at the same level as the system, and transmission efficiency can be improved.

  As described above, according to the radio communication system according to the present embodiment, radio propagation path information in which the reception SIR value of a specific subcarrier is thinned out by SIR 210 of mobile station 200 is created. The transmission efficiency on the link for notifying the propagation path information can be improved as compared with the case of notifying the base station 100 of the received SIR value.

  In the above description, the case where the radio propagation path information is generated based on the received SIR has been described. However, the present invention is not limited to this, and the received SNR (signal power to noise power ratio) is not limited to this. Radio channel information may be generated on the basis of: Signal to Noise Power Ratio (Signal to Noise Power Ratio) or SINR (Signal Power to Interference Plus Noise Power Ratio).

  Further, in the above description, the embodiment in the downlink from the base station 100 to the mobile station 200 has been described. However, the present invention is not limited to this, and the mobile pole 200 to the base station 100 is described. It is possible to adapt even in the uplink. Also in this case, it is possible to obtain the same effect as in the present embodiment.

  Furthermore, in the above description, the radio communication system that performs high-speed communication by adaptively changing the modulation scheme, the coding rate, etc. for each subcarrier based on the radio channel state on the receiver side has been described. The present invention is not limited to this, and 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 the radio channel conditions.

It is a block diagram which shows the structure of the base station which comprises the radio | wireless communications system which concerns on this invention. It is a block diagram which shows the structure of the mobile station which comprises the radio | wireless communications system which concerns on this invention. It is a figure for demonstrating the outline | summary of a 1st thinning-out algorithm. It is a flowchart for demonstrating a 1st thinning-out algorithm. It is a figure which shows an example of the frame format used in order to notify the reception SIR value of the subcarrier specified using the 1st thinning | decimation algorithm to a base station. It is a figure for demonstrating the outline | summary of the 2nd thinning-out algorithm. It is a flowchart for demonstrating a 2nd thinning-out algorithm. It is a figure which shows an example of the frame format used in order to notify the reception SIR value of the subcarrier specified using the 2nd thinning | decimation algorithm to a base station. It is a figure which shows the example of a table of the threshold value with respect to the inclination of a reception SIR curve in the 2nd thinning-out algorithm. It is a figure for demonstrating the outline | summary of the 3rd thinning-out algorithm. It is a flowchart for demonstrating the 3rd thinning_out | decimation algorithm. It is a figure which shows an example of the frame format used in order to notify the reception SIR value of the subcarrier specified using the 3rd thinning-out algorithm to a base station. It is a figure for demonstrating the outline | summary of the 4th thinning_out | decimation algorithm. It is a flowchart for demonstrating a 4th thinning_out | decimation algorithm. It is a figure which shows an example of the frame format used in order to notify the reception SIR value of the subcarrier specified using the 4th thinning-out algorithm to a base station. It is a figure for demonstrating the outline | summary of the 5th thinning_out | decimation algorithm. It is a flowchart for demonstrating the 5th thinning_out | decimation algorithm. It is a figure which shows an example of the frame format used in order to notify the reception SIR value of the subcarrier specified using the 5th thinning-out algorithm to a base station. It is a figure which shows an example of the common table previously hold | maintained by the base station and the mobile station. It is a figure which shows an example of the frame format for notifying the thinning-out algorithm selected in the mobile station to a base station. It is a figure which shows the example of the transmission power at the time of transmission from a base station. It is a figure which shows the example of the received signal of the mobile station at the time of receiving the influence of frequency fading. It is a figure which shows the example of a communication system which determines a modulation system and a coding rate based on the reception SIR of a mobile station. It is a figure for demonstrating the notification method of the propagation path information of a conventional system. It is a figure for demonstrating the example of a modulation system selected from the notification method of the propagation path information of a conventional system.

Explanation of symbols

100 Base station equipment (base station)
108 uplink reception processing section 109 SIR information extraction section 200 mobile station apparatus (mobile station)
207 SIR estimation unit 210 SIR information creation unit

Claims (12)

A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner;
Based on the estimation result by the propagation path state estimation unit, a propagation path information creation unit for creating propagation path information including subcarrier numbers of subcarriers identified from all subcarriers using a thinning algorithm and the estimation result;
A transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner,
The propagation path information creation unit is based on an estimation result from the propagation path condition estimation unit for subcarriers selected for each predetermined number and an estimation result from the propagation path condition estimation unit for the selected subcarriers. A radio transmitter characterized in that propagation path information is created from a linearly interpolated value, a subcarrier number having an estimation result with the largest error, and the estimation result. A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner;
Based on the estimation result by the propagation path state estimation unit, a propagation path information creation unit for creating propagation path information including subcarrier numbers of subcarriers identified from all subcarriers using a thinning algorithm and the estimation result;
A transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner,
The propagation path information creation unit includes a subcarrier number when the slope of a straight line obtained by connecting the estimation results from the propagation path state estimation unit for adjacent subcarriers changes by a predetermined value or more, and the estimation result A radio transmitter characterized by creating propagation path information from A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner;
Based on the estimation result by the propagation path state estimation unit, a propagation path information creation unit for creating propagation path information including subcarrier numbers of subcarriers identified from all subcarriers using a thinning algorithm and the estimation result;
A transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner,
The propagation path information creation unit determines the propagation path information from the subcarrier number when the sign of the slope of the straight line obtained by connecting the estimation results from the propagation path state estimation unit for adjacent subcarriers changes and the estimation result. A wireless transmitter characterized by creating a. A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner;
Based on the estimation result by the propagation path state estimation unit, a propagation path information creation unit for creating propagation path information including subcarrier numbers of subcarriers identified from all subcarriers using a thinning algorithm and the estimation result;
A transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner,
The propagation path information creation unit includes a subcarrier number when the sign of the slope of a straight line obtained by connecting the estimation results from the propagation path state estimation unit for adjacent subcarriers, the estimation result, and the straight line A radio transmitter characterized in that propagation path information is created from an estimation result for subcarriers arranged in the middle between subcarrier numbers whose slopes have changed in sign. A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner;
Based on the estimation result by the propagation path state estimation unit, a propagation path information creation unit for creating propagation path information including subcarrier numbers of subcarriers identified from all subcarriers using a thinning algorithm and the estimation result;
A transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner,
The propagation path information creation unit includes a subcarrier number when the sign of the slope of a straight line obtained by connecting the estimation results from the propagation path state estimation unit for adjacent subcarriers, the estimation result, and the straight line A radio transmitter characterized in that propagation path information is created from subcarrier numbers having an intermediate estimation result between subcarrier numbers in which the sign of the slope changes. A propagation path condition estimation unit that estimates a propagation path condition from a radio signal received from a communication partner;
Based on the estimation result by the propagation path state estimation unit, a propagation path information creation unit for creating propagation path information including subcarrier numbers of subcarriers identified from all subcarriers using a thinning algorithm and the estimation result;
A transmission processing unit that transmits the propagation path information created by the propagation path information creation unit to a communication partner,
The propagation path information creation unit
The estimation result from the propagation path condition estimation unit for the subcarriers selected for each predetermined number, and the value that is linearly interpolated based on the estimation result from the propagation path condition estimation unit for the selected subcarriers and the most error A method of creating propagation path information from a subcarrier number having a large estimation result and the estimation result,
A method of creating propagation path information from subcarrier numbers and estimation results when the slope of a straight line obtained by connecting the estimation results from the propagation path condition estimation unit for adjacent subcarriers changes by a predetermined value or more ,
A method of creating propagation path information from a subcarrier number when the sign of the slope of a straight line obtained by linking estimation results from the propagation path condition estimation unit for adjacent subcarriers and its estimation result,
The subcarrier number when the sign of the slope of the straight line obtained by connecting the estimation results from the propagation path state estimation unit for the adjacent subcarriers and the estimation result thereof, and the sub with the sign of the slope of the straight line changed. A method of creating propagation path information from an estimation result for subcarriers arranged in the middle between carrier numbers, or
The subcarrier number when the sign of the slope of the straight line obtained by connecting the estimation results from the propagation path state estimation unit for the adjacent subcarriers and the estimation result thereof, and the sub with the sign of the slope of the straight line changed. Among methods for creating propagation path information from subcarrier numbers having intermediate estimation results between carrier numbers,
A radio transmitter characterized in that the propagation path information is created by selecting a method that minimizes the data amount of the propagation path information.   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.   The radio transmitter according to claim 1, wherein the propagation path state estimation unit estimates a signal power to noise power ratio as a propagation path state.   The radio transmitter according to claim 1, wherein the propagation path state estimation unit estimates a signal power to interference noise power ratio as a propagation path state.   A mobile station apparatus comprising the radio transmitter according to any one of claims 1 to 9.   A base station apparatus comprising the wireless transmitter according to claim 1.   A mobile station apparatus comprising the radio transmitter according to any one of claims 7 to 9, and a modulation scheme and a coding rate are determined for each subcarrier using propagation path information received from the mobile station apparatus. A wireless communication system comprising: a base station device.

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