JP2006287551A - Radio communication deice and adaptive control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adaptive control method capable of determining the optimum number of transmission antennas and spreading factor, which reduce interference caused by space division multiplexing and interference caused by code division multiplexing to be able to suppress the reduction of a transmission rate as much as possible, and to provide a radio communication device using this method. <P>SOLUTION: The transmission device inserts known symbol strings for identifying respective transmission antennas, from which signals are transmitted, to the signals corresponding to the transmission antennas and transmits the signals from the transmission antennas respectively, and a reception device extracts known symbol signals corresponding to respective transmission paths specified by reception antennas and transmission antennas, from reception signals received by respective reception antennas, by addition and and subtraction of respective known symbols of known symbol strings and measures the magnitude of interference between known symbol signals and the magnitude of interference received by each known symbol signal and transmits reception state information including them, and the transmission device determines the number of transmission antennas and a spreading factor for code spreading on the basis of the received reception state information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radio communication system, and more particularly to a radio communication system to which a code division multiplexing (multiple access) scheme and a space division multiplexing (multiple access) scheme are applied.

  Recent wireless communication systems perform code division multiplexing (multiple access) against a strong demand for high speed and large capacity and high frequency utilization efficiency, and have a plurality of antennas in a transmission device and a reception device, and transmit wireless signals in space. A technique called space division multiplexing (multiple access) that achieves high speed by performing multiplexing is applied. Also, in response to fluctuations in the radio propagation path, which is also the greatest feature of radio communication, the receiving apparatus notifies the transmitting apparatus of information related to the radio propagation path, and the transmitting apparatus uses this to each receiving apparatus. For example, a technique called adaptive control for controlling communication speed or the like is applied. In this case, using the received signal demodulated by the receiver, measure the desired signal power to interference power ratio (SIR), etc., and notify the transmitter of this measurement result or control information calculated based on the measurement result Thus, adaptive control is realized.

As a conventional technique related to adaptive control in a wireless communication system in which the transmission apparatus and the reception apparatus as described above have a plurality of antennas and are connected by the code division multiple access scheme, the reception apparatus transmits from each transmission antenna of the transmission apparatus. The desired signal power-to-interference and noise power ratio (SINR) for the received signal is measured based on the result of demodulating the signal received at each receiving antenna, and further summed up to obtain radio propagation path information. There is one in which the transmission device adaptively controls the communication speed by notifying the transmission device (see, for example, Non-Patent Document 1).
3GPP TR25.876 v1.5.0 9 pages

  In a wireless communication system to which a plurality of multiplexing methods such as code division multiplexing and space division multiplexing are applied, interference signals received by a receiving apparatus include interference signals resulting from code division multiplexing and interference signals resulting from space division multiplexing. . However, in the above-described conventional wireless communication system, the receiving apparatus notifies the transmitting apparatus of the wireless propagation path information measured without distinguishing the above-described interference signal. Therefore, the transmission apparatus cannot distinguish the influence of each interference signal in the reception apparatus. Thus, when there are a plurality of interference signals having different properties, such as an interference signal due to code division multiplexing and an interference signal due to space division multiplexing, the transmission apparatus performs coding based on the size of each interference signal. There is a problem that adaptive control in which parameters related to division multiplexing and parameters related to space division multiplexing are made independent cannot be realized.

  Accordingly, the present invention has been made to solve the above-described problems, and is an optimum that can reduce interference caused by space division multiplexing and code division multiplexing and suppress a reduction in transmission rate as much as possible. An object of the present invention is to provide an adaptive control method capable of determining the number of transmission antennas and spreading factor and a wireless communication apparatus using the same.

  (1) In a wireless communication system including a transmission device including a plurality of antennas and a reception device including a plurality of reception antennas, (a) the transmission device code-spreads a modulated signal using a spreading code, and the plurality The number of transmitting antennas used for transmission is divided into the number of transmitting antennas to generate each signal corresponding to each transmitting antenna, and (b) the transmitting apparatus transmits the signal to each signal corresponding to each transmitting antenna. A known symbol sequence for identifying a transmission antenna to be transmitted is transmitted from each transmission antenna, and (c) the reception device receives a signal transmitted from each transmission antenna by each reception antenna; d) A combination of the receiving antenna and the transmitting antenna from each received signal by the receiving apparatus adding and subtracting each known symbol of the known symbol string Each known symbol signal corresponding to each more specific propagation path is extracted. (E) The receiver measures the magnitude of interference between the known symbol signals and the magnitude of interference received by each known symbol signal. (F) The reception apparatus transmits reception state information including the magnitude of interference between the known symbol signals and the magnitude of interference received by each known symbol signal, and (g) the transmission apparatus is received. Based on the reception status information, the number of transmission antennas and a spreading factor for code spreading are determined.

  The transmission device reduces the number of transmission antennas by a predetermined number when the magnitude of interference between the transmission signals included in the reception state information is larger than a predetermined threshold, and accordingly, transmission at each transmission antenna The magnitude of interference received by each transmission signal when the power is increased by a predetermined value is estimated, and the spreading factor is determined based on the magnitude of interference received by each estimated transmission signal.

  (2) In a wireless communication system including a transmission device including a plurality of antennas and a reception device including a plurality of reception antennas, (a) the transmission device code-spreads a modulated signal using a spreading code, and the plurality The number of transmitting antennas used for transmission is divided into the number of transmitting antennas to generate each signal corresponding to each transmitting antenna. (B) The transmitting apparatus transmits the signal to each signal corresponding to each transmitting antenna. A first known symbol sequence for identifying the antenna to be transmitted and a second known symbol sequence orthogonal to the first known symbol sequence are inserted and transmitted from each transmitting antenna; (c) the receiving device Each receiving antenna receives a signal transmitted from each transmitting antenna, and (d) the receiving device adds and subtracts each known symbol of the first known symbol sequence, From each received signal, each first known symbol signal corresponding to each propagation path specified by the receiving antenna and the transmitting antenna is extracted, and (e) the receiving device receives each first known symbol. Measuring the magnitude of interference received by the signal; (f) the receiving device extracting each second known symbol signal corresponding to each transmitting antenna; and (g) the receiving device receiving each second known symbol. Measure the magnitude of interference received by the signal, and (h) measure the magnitude of interference received by each of the first known symbol signals and the magnitude of interference received by each of the second known symbol signals. (I) The transmission apparatus determines the number of transmission antennas and a spreading factor for code spreading based on the received reception state information.

  When the difference between the magnitude of interference received by each transmission signal and the magnitude of interference between the transmission signals is greater than a predetermined threshold, the transmission device reduces the number of transmission antennas by a predetermined number, Accordingly, the magnitude of interference between the transmission signals when the transmission power at each transmission antenna is increased by a predetermined value is estimated, and based on the estimated magnitude of interference between the transmission signals, Determine the spreading factor.

  According to the present invention, it is possible to determine the optimum number of transmission antennas and spreading factor that can reduce interference caused by space division multiplexing and interference caused by code division multiplexing and suppress the reduction of transmission rate as much as possible.

  Hereinafter, this embodiment will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows an example of the configuration of a first wireless communication apparatus constituting the wireless communication system according to the first embodiment, and FIG. 2 shows the configuration of a second wireless communication apparatus constituting the wireless communication system according to the present embodiment. An example is shown.

  In FIG. 1, the first wireless communication apparatus is roughly composed of a transmission unit 1, a control unit 2, and a reception unit 3.

  The transmission unit 1 includes an antenna 101, a radio processing circuit 102, a second code multiplication circuit 103, a pilot insertion circuit 104, a data multiplexing circuit 105, a first code multiplication circuit 106, a modulation circuit 107, an S / P circuit 108, an error A correction encoding circuit 109 and a data distribution circuit 110 are included.

  In FIG. 1, two antennas 101 are provided. Therefore, the maximum value of the space division multiplexing number is “2”. Further, two each of the wireless processing circuit 102, the second code multiplication circuit 103, the pilot insertion circuit 104, and the data multiplexing circuit 105 are provided.

  When distinguishing each of the two antennas 101, they are referred to as antennas 101-1 and 101-2. When distinguishing each of the two wireless processing circuits 102, the wireless processing circuits 102-1 and 102-2 are used. When distinguishing each of the two second code multiplication circuits 103, the second code multiplication circuits 103-1 and 103-2 are used. When the two pilot insertion circuits 104 are distinguished from each other, they are referred to as pilot insertion circuits 104-1 and 104-2. When distinguishing each of the two data multiplexing circuits 105, the data multiplexing circuits 105-1 and 105-2 are used.

  In FIG. 1, the maximum number of multiplexed data series is N. Therefore, there are a maximum of N codes used for code division multiplexing. In addition, N first code multiplication circuits 106, modulation circuits 107, S / P circuits 108, and error correction coding circuits 109 are provided.

  When distinguishing each of the N first code multiplication circuits 106, the first code multiplication circuits 106-1 to 106-N are used. When distinguishing each of the N modulation circuits 107, the modulation circuits 107-1 to 107-N are used. In order to distinguish each of the N S / P circuits 108, the S / P circuits 108-1 to 108-N are used. When distinguishing each of the N error correction encoding circuits 109, the error correction encoding circuits 109-1 to 109-N are used.

  The receiving unit 3 includes an antenna 301, a radio processing circuit 302, a demodulation circuit 303, and an error correction decoding circuit 304.

  In FIG. 2, the second wireless communication apparatus is roughly composed of a transmission unit 4, a control unit 5, and a reception unit 6.

  The transmission unit 4 includes an antenna 401, a radio processing circuit 402, a modulation circuit 403, and an error correction coding circuit 404. The receiving unit 6 includes an antenna 601, a wireless processing circuit 602, a synchronization circuit 603, a code multiplication circuit 604, a transmission path estimation circuit 605, a synthesis circuit 606, a separation circuit 607, a demodulation circuit 608, a P / S circuit 609, and an error correction decoding circuit. 610 includes a reception state measurement circuit 611.

  In FIG. 2, two antennas 601 are provided. Two wireless processing circuits 602, two synchronization circuits 603, two sign multiplication circuits 604, and two transmission path estimation circuits 605 are provided.

  When the two antennas 601 are distinguished from each other, they are referred to as antennas 601-1 and 602-2. When the two wireless processing circuits 602 are distinguished from each other, the wireless processing circuits 602-1 and 602-2 are used. When the two synchronization circuits 603 are distinguished from each other, the synchronization circuits 603-1 and 603-2 are used. When distinguishing each of the two code multiplication circuits 604, they are referred to as code multiplication circuits 604-1 and 604-2. When distinguishing each of the two transmission path estimation circuits 605, the transmission path estimation circuits 605-1 and 605-2 are used.

  1 and FIG. 2 show a case where the number of space division multiplexing, that is, the number of antennas, and the number of circuits corresponding to the number are two, but the present invention is not limited to this, and is configured with an arbitrary number. Is possible.

  The operation of the transmission unit 1 of the first wireless communication apparatus in FIG. 1 will be described. The data distribution circuit 110 distributes the maximum number N of data series input from the upper I / F to each error correction coding circuit 109 corresponding to each data series. Each of the N error correction encoding circuits 109 performs error correction encoding on the input data sequence with an encoding method and encoding rate corresponding to each data sequence set by the control unit 2, An error correction encoded data sequence is generated. The error correction encoded data series is output to the corresponding S / P circuit 108.

  Each of the N S / P circuits 108 corresponds to the input error correction encoded data sequence corresponding to a predetermined number of spatial division multiplexing set by the control unit 2, that is, the number of antennas 101 used for transmission. It is converted (S / P conversion) into a data series (parallel data) of a number (space division multiplexing number, here, maximum “2”). Each data series is output to the corresponding modulation circuit 107.

  Each of the N modulation circuits 107 modulates each input data series by a modulation scheme corresponding to each data series set by the control unit 2 to generate each modulation signal. Each modulation signal is output to the corresponding first code multiplication circuit 106.

  Different N spreading codes that are orthogonal to each other are assigned to the N first code multiplication circuits 106. Each of the N first code multiplication circuits 106 is based on the spreading factor corresponding to each modulation signal set by the control unit 2 with respect to each input modulation signal. Is multiplied by the code assigned to, each of the input modulated signals is code spread to generate each code spread signal. The number of codes corresponds to the maximum data multiplexing number N. Each code spread signal generated by the first code multiplication circuit 106 is output to a different data multiplexing circuit 105 corresponding to the number of space division multiplexing.

  Each of the number of data multiplexing circuits 105 equal to the number of antennas 101 (two in this case) is multiplexed by adding the maximum number N of code spread signals that have been input to generate a multiplexed signal. The multiplexed signal is output to the corresponding pilot insertion circuit 104.

  Each of the number of pilot insertion circuits 104 equal to the number of antennas 101 (two in this case) adds a known symbol sequence having a predetermined signal pattern to the input multiplexed signal, and adds a corresponding second Output to the sign multiplication circuit 103.

  Each of the number of second code multiplication circuits 103 equal to the number of antennas 101 (two in this case) is scrambled as represented by a pseudo-random sequence with respect to the multiplexed signal in which the input known symbol sequence is inserted. The sign is multiplied and output to the corresponding wireless processing circuit 102.

  Each of the number of radio processing circuits 102 equal to the number of antennas 101 (two in this case) is configured to perform D / A (Digital to Analog) conversion, quadrature modulation, up-conversion, band limitation, A predetermined radio processing such as power amplification is performed to generate a radio signal. The wireless signal is transmitted from the antenna 101 to the wireless communication path.

  The operation of the receiving unit 6 of the second wireless communication apparatus in FIG. 2 will be described. Each of the two antennas 601 outputs a radio signal received from the radio communication path to each radio processing circuit 602 corresponding to each antenna 601.

  Each of the two wireless processing circuits 602 performs predetermined wireless processing such as band limitation, down-conversion, orthogonal demodulation, A / D (Analog to Digital) conversion, etc., on the input wireless signal, The data is output to each synchronization circuit 603, each code multiplication circuit 604, and each transmission path estimation circuit 605 corresponding to the wireless processing circuit 602.

  Radio processing circuit 602-1, synchronization circuit 603-1, code multiplication circuit 604-1, and transmission path estimation circuit 605-1 process a signal received by antenna 601-1. Radio processing circuit 602-2, synchronization circuit 603-2, code multiplication circuit 604-2, and transmission path estimation circuit 605-2 process a signal received by antenna 601-2.

  The synchronization circuit 603-1 uses the known symbol sequence included in the signal output from the radio processing circuit 602-1 and receives signals received via the antenna 601-1 through various paths (multipath). Detect the timing. Similarly, the synchronization circuit 603-2 uses the known symbol sequence included in the signal output from the radio processing circuit 602-2, and receives the signal received via the multipath propagation path received by the antenna 601-2. Detect the timing. Each synchronization circuit 603 outputs the timing (multipath timing) of each incoming signal to the transmission path estimation circuit 605 and the code multiplication circuit 604 corresponding to each synchronization circuit 603.

  The code multiplication circuit 604-1 uses a number of multiplication circuits equal to the number of detected multipaths “L1” (L1 <= M) based on the multipath timing notified from the corresponding synchronization circuit 603-1. Each input signal is multiplied by a scramble code and an orthogonal code, and the result is output to the synthesis circuit 606. Similarly, the sign multiplication circuit 604-2 multiplies a number equal to the number of detected multipaths “L2” (L2 <= M) based on the multipath timing notified from the corresponding synchronization circuit 603-2. The circuit is used to multiply each input signal by a scramble code and an orthogonal code corresponding to the second wireless communication apparatus, and the result is output to the synthesis circuit 606.

  The transmission path estimation circuit 605-1 performs transmission path estimation using the known symbol sequence for each of the detected L1 multipaths based on the multipath timing notified from the corresponding synchronization circuit 603-1. Do. The transmission path estimation result is notified to the synthesis circuit 606 and the separation circuit 607 and also output to the reception state measurement circuit 611. Similarly, the transmission path estimation circuit 605-2 transmits each of the detected L2 multipaths using the known symbol sequence based on the multipath timing notified from the corresponding synchronization circuit 603-2. Perform path estimation. The transmission path estimation result is notified to the synthesis circuit 606 and the separation circuit 607 and also output to the reception state measurement circuit 611.

  The combining circuit 606 combines a plurality of incoming signals received by the antenna 601-1 of the receiving unit 6 of the second wireless communication apparatus based on the input signal and the notified transmission path estimated value, and the antenna 601- 1 generates the signal received. In addition, a plurality of incoming signals received by the antenna 601-2 are combined to generate a signal received by the antenna 601-2. The two generated signals are output to the separation circuit 607.

  The separation circuit 607 is transmitted from the antenna 101-1 of the first wireless communication apparatus, which is spatially multiplexed from the two signals, based on the two input signals and the notified transmission path estimation value. The signal and the signal transmitted from the antenna 101-2 are separated from each other, and these two signals are output to the demodulation circuit 608.

  Demodulation circuit 608 demodulates the two input signals by a demodulation method corresponding to a predetermined modulation method, and outputs two series of demodulated data obtained as a result to P / S circuit 609. . The P / S circuit 609 performs P / S conversion on the input two series of demodulated data, and outputs the resulting one series of data to the error correction decoding circuit 610. The error correction decoding circuit 610 decodes the input data based on a predetermined encoding method and encoding rate, and outputs the data obtained as a result to the upper I / F.

  The reception state measurement circuit 611 uses the received transmission path estimation value as a reception state, as a reception state, a desired signal power-to-interference and noise power ratio (SINR) indicating the magnitude of an interference signal caused by code division multiplexing, a space A spatial correlation indicating the magnitude of the interference signal resulting from the division multiplexing is measured, and reception state information including these measurement results is output to the control unit 5 for transmission to the first wireless communication apparatus.

  Here, the case where there is one orthogonal code assigned to the second wireless communication apparatus (when one series of N series of data multiplexed by the first wireless communication apparatus is received). As shown, when a plurality of orthogonal codes are assigned (when receiving a plurality of sequences of N-sequence data multiplexed by the first wireless communication apparatus), a code multiplication circuit 604, a synthesis circuit This can be easily realized by providing the number 606, the separation circuit 607, and the demodulation circuit 608 as many as the number of assigned orthogonal codes.

  The control unit 5 outputs the reception state information input from the reception state measurement circuit 611 to the transmission unit 4. Note that adaptive control information determined based on the reception state information may be output to the transmission unit 4.

  Next, the transmission unit 4 will be described. The error correction coding circuit 404 performs error correction coding on the transmission data input from the upper I / F with a predetermined coding method and coding rate, and outputs the resulting data to the modulation circuit 403 To do. The modulation circuit 403 modulates the input data by a predetermined modulation method, and outputs a signal obtained as a result to the wireless processing circuit 402. The radio processing circuit 402 performs predetermined radio processing such as D / A conversion, quadrature modulation, up-conversion, band limitation, and power amplification on the input signal to generate a radio signal, and the radio signal is an antenna. 401 is transmitted to the wireless communication path.

  Next, the receiving unit 3 of the first wireless communication apparatus in FIG. 1 will be described. The antenna 301 outputs a radio signal received from the radio communication path to the radio processing circuit 302, and the radio processing circuit 302 performs predetermined limits such as band limitation, down-conversion, orthogonal demodulation, A / D conversion on the input radio signal. Radio processing is performed, and a signal obtained as a result is output to the demodulation circuit 303. The demodulation circuit 303 demodulates the input signal by a demodulation method corresponding to a predetermined modulation method. When the data obtained as a result of demodulation is the reception state information or the adaptive control information determined based on the reception state information, the data is output to the control unit 2. When the data obtained as a result of demodulation is data other than the reception state information or adaptive control information, the data is output to the error correction decoding circuit 304. The error correction decoding circuit 304 decodes the input data based on a predetermined encoding method and encoding rate, and outputs the data obtained as a result to the upper I / F.

  The control unit 2 of the first wireless communication apparatus in FIG. 1 will be described. The control unit 2 controls the transmission unit 1 using the reception state information or adaptive control information input from the demodulation circuit 303, that is, the reception state information or adaptive control information transmitted from the second wireless communication apparatus in FIG. To do. As described above, the reception state information is information (SINR) indicating the magnitude of interference caused by code division multiplexing and the magnitude of interference caused by space division multiplexing, measured by the second wireless communication apparatus. Information (spatial correlation) is included. At this time, the control on the transmission unit 1 is, for example, controlling the modulation scheme, coding rate, number of multiplexed data, spreading factor, number of transmission antennas, transmission power, transmission scheme, and the like.

  When a signal transmitted from the first wireless communication apparatus (hereinafter referred to as a transmission apparatus) in FIG. 1 is received by the second wireless communication apparatus (reception apparatus) in FIG. 2, interference caused by code division multiplexing in the reception apparatus. And the magnitude of interference due to space division multiplexing are measured separately and notified to the transmitter, so that the transmitter can perform adaptive control according to the two types of interference. It becomes.

  FIG. 3 is a diagram for explaining operations of the second code multiplication circuit 103, the pilot insertion circuit 104, the data multiplexing circuit 105, and the first code multiplication circuit 104 in the first wireless communication apparatus of FIG. 1 in more detail. It is.

  Each of the first code multiplication circuits 106-1, 106-2,... 106-N is assigned a code (1), a code (2),. . Each code corresponds to each of N receiving apparatuses (second wireless communication apparatuses).

  The first code multiplication circuits 106-1, 106-2,... 106-N respectively output predetermined space division multiplexing numbers (for example, “ 2 ”) is multiplied by codes (1), (2),... (N) to generate code spread signals.

  The two code spread signals generated by each first code multiplication circuit 106 are output to data multiplexing circuits 105-1 and 105-2, respectively. Therefore, each of a plurality of N data series to be space-division multiplexed input to the data distribution circuit 110 is spread by the same code. Note that the codes (1), (2),... (N) are different codes that are orthogonal to each other.

  The data multiplexing circuit 105-1 generates a multiplexed signal to be transmitted by the antenna 101-1, by adding the input N code spread signals. The generated multiplexed signal is output to pilot insertion circuit 104-1. The data multiplexing circuit 105-2 adds the input N code spread signals to generate a multiplexed signal to be transmitted by the antenna 101-2. The generated multiplexed signal is output to pilot insertion circuit 104-2.

  In each of pilot insertion circuits 104-1 and 104-2, a known symbol string (pilot signal) having a predetermined pattern is stored in advance. The pilot insertion circuit 104-1 adds the known symbol sequence stored in advance to the input multiplexed signal to insert the known symbol sequence, and sends it to the second code multiplication circuit 103-1. Output. The pilot insertion circuit 104-2 inserts the known symbol sequence by adding the previously stored known symbol sequence to the input multiplexed signal, and sends it to the second code multiplication circuit 103-2. Output.

  Each of the second code multiplication circuits 103-1 and 103-2 multiplies an input multiplexed signal (added (inserted) a known symbol string) by a scramble code such as a pseudo-random sequence. To the wireless processing circuits 102-1 and 102-2, respectively.

  Each known symbol sequence added by the pilot insertion circuits 104-1 and 104-2 is transmitted from the signal received by any one antenna of the second wireless communication device on the reception side to the first wireless communication device on the transmission side. It has a pattern that can separate the signals transmitted by each antenna. That is, the known symbol sequences added by pilot insertion circuits 104-1 and 104-2 are such that the signals received by the second wireless communication device are the antennas 101-1 and 101-2 of the first wireless communication device. Is used to identify the antenna from which the signal is transmitted.

  For example, A is an arbitrary symbol, and a symbol orthogonal to the symbol A is -A. The known symbol sequence inserted by pilot insertion circuit 104-1 has a pattern (A, A), and the known symbol sequence inserted by pilot insertion circuit 104-2 has a pattern (A, -A). Have.

  The pattern of the known symbol sequence is not limited to this. For example, the pilot insertion circuit 104-1 inserts a known symbol sequence having a pattern (A, A, A, A), and the pilot insertion circuit 104-2 (A, A, A). A known symbol sequence of A, -A, -A) may be inserted.

  Next, the transmission path estimation circuit 605 of the second wireless communication apparatus described above will be described with reference to FIG. Here, pilot insertion circuit 104-1 of the first wireless communication apparatus described above inserts a known symbol string having a symbol pattern (A, A), and pilot insertion circuit 104-2 becomes (A, -A). A case where a known symbol string having a symbol pattern is inserted will be described as an example.

  The transmission path estimation circuit 605 performs transmission path estimation for each detected multipath using the known symbol sequence based on the multipath timing notified from the synchronization circuit 603. When L ((L1 = L2 = L <= M)) multipaths are detected by the synchronization circuit 603, transmission path estimation is performed for each of them. This means that L transmission path estimation circuits 605 operate simultaneously.

  The transmission path estimation circuit 605 includes all multipaths for each antenna used for transmission by the first wireless communication device (transmitting device) and for each antenna used for reception by the second wireless communication device (receiving device). Then, transmission path estimation is performed to obtain a transmission path estimation result. Therefore, the total number of “the number of antennas used for transmission by the first wireless communication device” × “the number of antennas used for reception by the second wireless communication device” × “the number of detected multipaths” Thus, the transmission path estimation result is obtained.

  Here, assuming that the antenna of the transmitting apparatus is T and the antenna of the receiving apparatus is S, the propagation path rTS corresponding to the u (u <= M) -th multipath transmitted from the antenna T and received by the antenna S. The transmission path estimation result of (u) is represented as hTS (u). For example, the propagation path corresponding to the first multipath transmitted by the first transmission antenna 101-1 and received by the first reception antenna 601-1 is r11 (1), and the transmission path estimation result is h11 (1 ), The propagation path corresponding to the first multipath transmitted by the second transmission antenna 101-2 and received by the second reception antenna 601-2 is r22 (1), and the transmission path estimation result is h22. (1), the propagation path corresponding to the third multipath transmitted by the first transmission antenna 101-1 and received by the second reception antenna 601-2 is r12 (3), and the transmission path estimation result Is represented as h12 (3).

  In addition, in order to distinguish between the average hTS (u) _AV of the channel estimation result hTS (u) of the channel rTS (u), which will be described later, and the hTS (u), hTS (u) is used as the channel rTS (u). ), The first transmission path estimation result hTS (u) _AV is referred to as the second transmission path estimation result of the propagation path rTS (u).

  Here, referring to FIG. 4, transmission path estimation circuits 605-1 and 605-2 for the first incoming signal among the L incoming signals received by antenna 601-1 and antenna 601-2, respectively. A case where the channel estimation is performed will be described.

  Also, since the configurations of the transmission path estimation circuits 605-1 and 605-2 are the same, here, first, the transmission path estimation circuit that performs transmission path estimation for the first incoming signal received by the antenna 601-1. Reference will be made to 605-1.

  The transmission line estimation circuit 605-1 first performs a first wireless communication with the multiplication circuit 701 on the signal input from the wireless processing circuit 602-1 in synchronization with the multipath timing notified from the synchronization circuit 603. The same code as the scramble code multiplied by the second code multiplication circuit 103 of the apparatus is multiplied. Here, the unit of the multiplication result is referred to as a chip.

  Subsequently, in the adder circuit 702, the multiplication result output from the multiplier circuit 701 is inserted into a predetermined PSF (Pilot Spreading Factor) chip, that is, the rate of the scramble code and the known insertion inserted by the pilot insertion circuit 104 of the first wireless communication apparatus. The number of chips corresponding to the rate ratio of the symbol sequence is added. Here, the unit of the addition result output from the addition circuit 702 is referred to as a symbol. That is, 1 symbol = PSF chip.

  The amplitude adjustment circuit 703 adjusts the amplitude of the addition result output from the addition circuit 702. This amplitude adjustment is realized, for example, by dividing the addition result by PSF. Each symbol output from the amplitude adjustment circuit 703 is input to the addition circuit 704a and the subtraction circuit 704b.

  The adder circuit 704a adds the two symbols when two symbols are continuously input. In addition, when two symbols are continuously input, the subtraction circuit 704b performs subtraction between the two symbols.

  In the amplitude adjustment circuit 705a, the amplitude is adjusted with respect to the addition result output from the addition circuit 704a, and the first transmission path estimation result h11 (1) of the propagation path r11 (1) obtained as a result is received state measurement. It outputs to the circuit 611 and the averaging circuit 706a. The amplitude adjustment circuit 705b performs amplitude adjustment on the subtraction result output from the subtraction circuit 704b, and receives the first transmission path estimation result h21 (1) of the propagation path r21 (1) obtained as a result of the reception state measurement. Output to the circuit 611 and the averaging circuit 706b.

  Since the amplitude adjustment circuit 705a adds two symbols, the amplitude is adjusted by dividing the addition result by “2”, for example. Similarly, since the amplitude adjustment circuit 705b performs subtraction between two symbols, for example, the amplitude is adjusted by dividing the subtraction result by “2”.

  A known symbol sequence having two symbols (A, A) is transmitted from the first antenna 101-1 of the first wireless communication apparatus, and two (A, -A) are transmitted from the second antenna 101-2. In the case where a known symbol sequence having symbols is transmitted, as described above, when 2 symbols are added by the adder circuit 704a, the known symbol sequence in which the known symbol sequence transmitted by the first antenna 101-1 is “2A”. However, the known symbol sequence transmitted by the second antenna 101-2 is “0” and is not detected. On the other hand, as described above, when 2 symbols are subtracted by the subtracting circuit 704b, the known symbol sequence transmitted by the second antenna 101-2 is detected as a known symbol signal “2A”. The known symbol sequence transmitted at 101-1 is "0" and is not detected.

  That is, what is output from the amplitude adjustment circuit 705a is transmitted from the first antenna 101-1 of the first wireless communication apparatus and received by the first antenna 601-1 of the second wireless communication apparatus. This is a known symbol signal “A” of the symbol string. Also, what is output from the amplitude adjustment circuit 705b is transmitted from the first antenna 101-2 of the first wireless communication apparatus and received by the second antenna 601-2 of the second wireless communication apparatus. This is a known symbol signal “A” of the symbol string.

  As described above, the transmission path estimation circuit 705a uses the known symbol signal “A” extracted from each incoming signal received by the first antenna 601-1 and the second antenna 602-2 of the second wireless communication apparatus. Is output as the first transmission path estimation result of each propagation path.

  In the averaging circuit 706a, when a predetermined number of addition results (that is, known symbol signals “A”) subjected to amplitude adjustment are obtained, the addition average is calculated. The addition average of the known symbol signal “A” is the second transmission path estimation result h11 (1) _AV of the propagation path r11 (1). The second transmission path estimation result is notified to the synthesis circuit 606 and the separation circuit 607 and further output to the reception state measurement circuit 611. Similarly, the averaging circuit 706b calculates the addition average when a predetermined number of addition results (that is, known symbol signal “A”) subjected to amplitude adjustment are obtained, and the propagation path r21 (1 ) Second transmission path estimation result h21 (1) _AV. The second transmission path estimation result is notified to the synthesis circuit 606 and the separation circuit 607 and further output to the reception state measurement circuit 611.

  The transmission path estimation circuit 605-2 uses the first transmission path of the propagation path r12 (1) for the first incoming signal received by the antenna 601-2 in the same manner as the transmission path estimation circuit 605-1. Estimation result h12 (1) and second transmission path estimation result h12 (1) _AV, first transmission path estimation result h22 (1) of propagation path r22 (1), and second transmission path estimation result h22 (1) _AV is calculated.

  In the above-described operation example, addition and subtraction are performed in units of two symbols, so that the amplitude adjustment for both results is realized by dividing by “2”. However, for example, the pilot insertion circuits 104-1 and 104-2 in the first wireless communication apparatus have known symbols having symbol patterns of (A, A, A, A) and (A, A, -A, -A). When columns are respectively inserted, the addition circuit 704a and the subtraction circuit 704b perform addition and subtraction in units of 4 symbols. The amplitude adjustment circuits 705a and 705b adjust the amplitude by dividing the addition result by the addition circuit 704a and the subtraction result by the subtraction circuit 704 by “4”.

  Also in this case, what is output from the amplitude adjustment circuit 705a is transmitted from the first antenna 101-1 of the first wireless communication apparatus and received by the first antenna 601-1 of the second wireless communication apparatus. The known symbol signal “A” in the known symbol string, which is output from the amplitude adjustment circuit 705b, is transmitted from the first antenna 101-2 of the first wireless communication apparatus, and is transmitted from the second wireless communication apparatus. A known symbol signal “A” of a known symbol sequence received by the second antenna 601-2 of the apparatus.

  Next, the reception state measurement circuit 611 in the second wireless communication apparatus described above will be described with reference to FIG. The reception state measurement circuit 611 includes the first transmission path estimation result hTS (u) and the second transmission of each transmission path rTS (u) calculated by the transmission path measurement circuits 605-1 and 605-2 in FIG. The path estimation result hTS (u) _AV is input. Note that u = 1 to L.

  The first synthesis circuit 801a of the reception state measurement circuit 611 is transmitted by the first antenna 101-1 of the first wireless communication apparatus and received by the first antenna 601-1 of the second wireless communication apparatus. The first transmission path estimation results h11 (1) to h11 (L) of the propagation paths r11 (1) to r11 (L) are converted into the second transmission path estimation results h11 (1) _AV to h11 (L). Using _AV, synthesis is performed in the same manner as the synthesis circuit 606. That is, the signal has been propagated via the propagation paths r11 (1) to r11 (L) from the first antenna 101-1 of the first wireless communication apparatus to the first antenna 601-1 of the second wireless communication apparatus. A known symbol signal “A” is synthesized from each known symbol string.

  Similarly, the second combining circuit 801b transmits each propagation path transmitted by the first antenna 101-1 of the first wireless communication apparatus and received by the second antenna 601-2 of the second wireless communication apparatus. The first transmission path estimation results h12 (1) to h12 (L) of r12 (1) to r12 (L) are used as the second transmission path estimation results h12 (1) _AV to h12 (L) _AV. Then, they are synthesized by the same method as the synthesis circuit 606. That is, the signal has been propagated via the propagation paths r12 (1) to r12 (L) from the first antenna 101-1 of the first wireless communication apparatus to the second antenna 601-2 of the second wireless communication apparatus. A known symbol signal “A” is synthesized from each known symbol string.

  The third synthesis circuit 801c transmits each propagation path r21 (1) transmitted from the second antenna 101-2 of the first wireless communication apparatus and received by the first antenna 601-1 of the second wireless communication apparatus. ) To r21 (L), the first transmission path estimation values h21 (1) to h21 (L) are combined using the second transmission path estimation values h21 (1) _AV to h21 (L) _AV. Synthesis is performed in the same manner as the circuit 606. That is, the signal has been propagated via the propagation paths r21 (1) to r21 (L) from the second antenna 101-2 of the first wireless communication apparatus to the first antenna 601-1 of the second wireless communication apparatus. A known symbol signal “A” is synthesized from each known symbol string.

  The fourth combining circuit 801d transmits each propagation path r22 (1) transmitted by the second antenna 101-2 of the first wireless communication apparatus and received by the second antenna 601-2 of the second wireless communication apparatus. ) To r22 (L), the first transmission path estimation results h22 (1) to h22 (L) are combined using the second transmission path estimation results h22 (1) _AV to h22 (L) _AV. Synthesis is performed in the same manner as the circuit 606. That is, the signal has been propagated via the propagation paths r22 (1) to r22 (L) from the second antenna 101-2 of the first wireless communication apparatus to the second antenna 601-2 of the second wireless communication apparatus. A signal of a known symbol signal “A” is synthesized from each known symbol string.

  The first SINR measurement circuit 802a is transmitted by the first antenna 101-1 of the first wireless communication apparatus based on the combination result of the known symbol signal “A” output from the first combination circuit 801a. Calculate a desired signal power to interference and noise power ratio (SINR) of a signal received by the first antenna 601-1 of the second wireless communication device.

  The second SINR measurement circuit 802b is transmitted by the first antenna 101-1 of the first wireless communication apparatus based on the synthesis result of the known symbol signal “A” output from the second synthesis circuit 801b. The SINR of the signal received by the second antenna 601-2 of the second wireless communication apparatus is calculated.

  The third SINR measurement circuit 802c is transmitted by the second antenna 101-2 of the first wireless communication apparatus based on the synthesis result of the known symbol signal “A” output from the third synthesis circuit 801c. The SINR of the signal received by the first antenna 601-1 of the second wireless communication apparatus is calculated.

  The fourth SINR measurement circuit 802d is transmitted by the second antenna 101-2 of the second wireless communication apparatus based on the synthesis result of the known symbol signal “A” output from the fourteenth synthesis circuit 801d, The SINR of the signal received by the second antenna 601-2 of the second wireless communication apparatus is calculated.

  The correlation measurement circuit 803 calculates a spatial correlation (ρ) based on the synthesis result of the known symbol signal “A” output from the first synthesis circuit 801a to the fourth synthesis circuit 801d.

In the first SINR measurement circuit 802a to the fourth SINR measurement circuit 802d, the transmission is performed from the mth transmission antenna of the first wireless communication apparatus and the nth of the second wireless communication apparatus from the following equation (1). The SINR _mn of the signal received by the receiving antenna is calculated. Here, the first transmission antenna of the first wireless communication apparatus is the antenna 101-1, the second transmission antenna is the antenna 101-2, and the first reception antenna of the second wireless communication apparatus is the antenna. The first and second receiving antennas 601-1 are the antenna 601-2.

In Equation (1), P _mn is transmitted from the m-th transmission antenna of the first wireless communication apparatus and is received by the n-th reception antenna of the second wireless communication apparatus. , N is an arbitrary integer, and is the number of synthesis results of the known symbol “A” used to calculate SINR _mn . Here, n = 1, 2, and m = 1, 2.

In the first SINR measurement circuit 802a to the fourth SINR measurement circuit 802a, SINR ₁₁ , SINR ₁₂ , SINR ₂₁ , and SINR ₂₂ are respectively calculated using Expression (1).

In correlation measurement circuit 802, from the following equation (2), a signal sequence transmitted from the xth transmission antenna of the first wireless communication device and a signal sequence transmitted from the yth transmission antenna of the first wireless communication device. The spatial correlation ρ _xy with is calculated. Note that n is the number of antennas included in the second wireless communication apparatus. Here, the spatial correlation ρ ₁₂ between the signal transmitted from the first antenna 101-1 of the first wireless communication apparatus and the signal transmitted from the second antenna 101-1 is calculated.

The average circuit 804 is a transmission path (propagation) between the first antenna 101-1 and the first antenna 601-1 calculated by each of the first SINR measurement circuit 802a to the fourth SINR measurement circuit 802d. SINR ₁₁ in the path), SINR ₁₂ in the transmission path (propagation path) between the first antenna 101-1 and the second antenna 601-2, the second antenna 101-2 and the first antenna 601-1. SINR ₂₁ in the transmission path (propagation path) between the second antenna 101-2 and the SINR ₂₂ in the transmission path (propagation path) between the second antenna 101-2 and the first antenna 601-2, that is, the first SINR of a transmission path (propagation path) between the wireless communication apparatus and the second wireless communication apparatus is calculated.

The reception state information including the SINR of the transmission path between the first wireless communication device and the second wireless communication device calculated by the average circuit 804 and the spatial correlation ρ ₁₂ calculated by the correlation measurement circuit 803 is the control unit. 5 is output. The reception status information is calculated by each of the first SINR measurement circuit 802a to the fourth SINR 802d in place of the SINR calculated by the average circuit 804 or together with the SINR calculated by the average circuit 804. SINR ₁₁ , SINR ₁₂ , SINR ₂₁ , SINR ₂₂ may be included.

  As shown in FIG. 16, a first wireless communication device (hereinafter simply referred to as a base station) BS1 and first and second wireless communication devices (hereinafter simply referred to as terminals) TE1 and TE2 communicate with each other. Suppose you are going. The terminal TE2 exists in an area where the respective communication areas of the base stations BS1 and BS2 overlap. At this time, if the signal transmitted from the base station BS2 and the signal transmitted from the base station BS1 are in the same frequency band, the signal transmitted from the base station BS2 is transmitted from the base station BS1 to the terminal TE2. The signal is an interference signal resulting from code division multiplexing. The influence of the interference signal appears in the SINR value. The greater the influence of the interference signal, the smaller the SINR value. The smaller the influence of the interference signal, the larger the SINR value.

  In addition, when the first wireless communication apparatus performs transmission using a plurality of transmission antennas, a signal transmitted from another transmission antenna interferes with a signal transmitted from one of the plurality of transmission antennas. Signal. The influence of the interference signal appears in the value of the spatial correlation. The greater the influence of the interference signal, the larger the spatial correlation. The smaller the influence of the interference signal, the smaller the spatial correlation.

In this way, from the SINR ₁₁ , SINR ₁₂ , SINR ₂₁ , SINR ₂₂ , and SINR calculated by the average circuit 804 measured by the first SINR measurement circuit 802a to the fourth SINR measurement circuit 802d, The magnitude of interference received by each transmitted signal, that is, the magnitude of the interference signal resulting from code division multiplexing can be specified. Further, from the spatial correlation measured by the correlation measurement circuit 803, the magnitude of interference between signals transmitted from the respective transmission antennas, that is, the magnitude of interference signals resulting from space division multiplexing can be specified.

  Therefore, the control unit 5 notifies the first wireless communication device of the reception state information including the above-described two measurement results output from the reception state measurement circuit 611, so that the first wireless communication device Using the two measurement results, adaptive control can be performed according to the magnitude of interference caused by different factors.

  That is, as the spatial correlation is larger, the second wireless communication apparatus is in a reception state in which the interference due to the number of antennas used for transmission (number of transmission antennas) in the first wireless communication apparatus is larger. Is preferred. By reducing the number of transmission antennas, the transmission power at each antenna can be increased. As a result, the SINR value can be expected to increase, but the transmission rate from the first wireless communication apparatus to the second wireless communication apparatus decreases as the number of transmission antennas decreases.

  When the spatial correlation is less than or equal to a predetermined threshold (Sth), the second wireless communication apparatus can almost ignore the influence of interference due to the number of antennas (number of transmission antennas) used for transmission in the first wireless communication apparatus. In order to increase the transmission rate, it is preferable that the number of transmission antennas be as large as possible. It is necessary to reduce the transmission power allocated to each antenna by increasing the number of transmission antennas. As a result, the SINR value may be reduced.

  Further, the SINR value increases as the spreading factor increases, but the transmission rate decreases as the spreading factor increases. The lower the spreading factor, the more susceptible to interference signals resulting from code spread multiplexing, the smaller the SINR value, but the lower the spreading factor, the higher the transmission rate.

  Therefore, when the number of transmission antennas is reduced, it is desirable to reduce the spreading factor by the amount of transmission antennas reduced (increase in the SINR value) in order to reduce the transmission rate as much as possible. However, the lower the spreading factor, the more susceptible to interference signals resulting from code spread multiplexing.

  In addition, when the number of transmission antennas is increased, the transmission power allocated to each antenna is reduced, so that the SINR value may be reduced.

  Therefore, as shown in FIGS. 6 and 8, the control unit 5 of the second wireless communication apparatus reduces the number of transmission antennas and increases the SINR value correspondingly to reduce interference caused by the number of transmission antennas. Based on the above, the diffusion rate is determined. As the SINR increases, the spreading factor can be lowered, so that a higher transmission rate can be ensured. In addition, when the interference due to the transmission antenna is small, the number of transmission antennas is increased. When interference due to code division multiplexing is large (when SINR is less than a predetermined first threshold value (Cthmin)), the spreading factor is increased until SINR is equal to or higher than the first threshold value, resulting from code division multiplexing. Reduce interference. Further, when there is almost no interference due to code division multiplexing (when SINR is sufficiently large), the spreading factor is lowered.

  With reference to FIGS. 6 to 8, the operation of the control unit 2 of the first wireless communication apparatus will be described in detail. Here, a case where the number of antennas of the transmission unit 1 of the first wireless communication apparatus is “2” and the PSF is “256” will be described as an example.

  FIG. 6 is a flowchart for explaining an outline of the operation of the control unit 2. When the control unit 2 starts communication with the second wireless communication device, the control unit 2 determines the spreading factor (SF) and the data multiplexing number from the communication quality requested by the second wireless communication device (step S2). S1). Then, in consideration of the determined spreading factor and the number of multiplexed data, in order to determine the modulation scheme and coding rate from the SINR notified from the second wireless communication terminal, optimal SINR, modulation scheme (Mod), A table M as shown in FIG. 7 showing the combination of coding rates (R) is created (step S2).

  In the table M shown in FIG. 7, each combination including SINR, modulation scheme (Mod), and coding rate (R) is indicated with an index number (No). Here, a case where the spreading factor is determined to be “16” and the data multiplexing number is determined to be “1” will be described as an example.

  Thereafter, the control unit 2 periodically checks whether the reception state information is notified from the second wireless communication device (step S3).

  When the reception state information is notified, the number of antennas to be transmitted is determined using the spatial correlation included in the reception state information (step S4). Specifically, when the spatial correlation is greater than a predetermined threshold (Sth), it is determined that the interference due to space division multiplexing is large, and the process proceeds to step S5.

  In step S5, the number of antennas used for transmission is set to “1”. Accordingly, the transmission power is increased by the amount that the number of antennas used for transmission is reduced. For example, here, assuming that transmission power of each antenna when transmitting using two antennas is P, it is 2P when transmitting using one antenna.

  On the other hand, if the spatial correlation is equal to or less than the predetermined threshold (Sth) in step S4, the process proceeds to step S8, and the number of antennas used for transmission is set to “2”. Accordingly, the transmission power at each antenna is set to P, and the process proceeds to step S9.

If it is determined in step S5 that the number of antennas used for transmission is “1”, the process proceeds to step S6, and antennas used for transmission are selected. In this case, the reception state information notified from the second wireless communication apparatus includes SINRs (SINR ₁₁ , SINR ₁₂ , SINR ₂₁ , SINR ₂₂ ) corresponding to each of the four propagation paths for each transmission antenna and reception antenna. In this case, among the antennas 101-1 and 1010-2, the SINRs for both are compared, and the antenna having the larger SINR is selected.

  As the transmission power at each antenna is increased in step S5, the subsequent SINR is expected to increase. Therefore, the process proceeds to step S7, the SINR value notified by the reception state information is increased by the amount corresponding to the increase in transmission power, and the process proceeds to step S9.

  In step S9, when the SINR included in the reception state information or the SINR is corrected in step S7, a spreading factor determination process as shown in FIG. 8 is performed using the corrected SINR.

  In FIG. 8, first, in step S21, when the SINR included in the reception state information or the SINR is corrected in step S7, the corrected SINR is compared with a predetermined threshold value Cthmin, and the SINR is equal to the threshold value Cthmin. Is smaller than that, it is determined that the interference due to code division multiplexing is large, and the process proceeds to step S22.

  In step S22, the diffusion rate is increased. In general, the higher the spreading factor, the greater the SINR. Therefore, the SINR value is increased by the amount corresponding to the increase in the spreading factor. For example, the spreading factor (SF) is doubled and the SINR is corrected to be increased by “3 dB”. And it returns to step S21 again and repeats the process of step S22 until this corrected SINR becomes more than threshold value Cthmin.

  Here, the threshold value Cthmin is set smaller than the minimum SINR on the table M in FIG. That is, when the SINR becomes small enough to deviate from a predetermined range, the reception state is improved by increasing the spreading factor and increasing the gain by spreading. At this time, the maximum value of the spreading factor is PSF.

  If the SINR is greater than or equal to the threshold value Cthmin in step S21, the process proceeds to step S23. In step S23, the SINR is compared with a predetermined threshold Cthmax. If the SINR is larger than the threshold Cthmax, the process proceeds to step S24.

  In step S24, the spreading factor (SF) is lowered, and the SINR value is reduced by the amount that the spreading factor is lowered. For example, the spreading factor is halved and the SINR is decreased by “3 dB”. And it returns to step S23 again and repeats the process of step S24 until this corrected SINR becomes smaller than the threshold value Cthmax.

  Here, the threshold value Cthmax is set larger than the maximum SINR on the table M in FIG. That is, when the SINR increases to the extent that it deviates from the predetermined range, the transmission rate is improved by reducing the spreading factor. At this time, the minimum value of the spreading factor is arbitrarily determined.

  Returning to the description of FIG. As described above, the SINR notified by the reception state information is corrected by the process (FIGS. 6 and 8) for determining the number of transmission antennas and the spreading factor. In step S10, the optimum modulation scheme and coding rate corresponding to the corrected SINR value are determined with reference to the table M in FIG. In addition, the process of the said step S3-step S10 is performed continuously while the 1st radio | wireless communication apparatus and the 2nd radio | wireless communication apparatus are communicating (step S11).

  The control unit 2 of the first wireless communication apparatus performs the processing shown in FIGS. 6 and 8 on the basis of the reception state information transmitted from the second wireless communication apparatus, and sends the second wireless communication apparatus to the second wireless communication apparatus. On the other hand, parameters such as the coding rate in the error correction coding circuit 109, the modulation method in the modulation circuit 107, the spreading factor in the first code multiplication circuit 106, the number of transmission antennas, the transmission power, etc. are determined, Are controlled (adaptive control) to operate according to the determined parameters.

  In the above description, the control unit 2 of the first wireless communication device performs adaptive control based on the reception state information notified from the second wireless communication device. The control unit 5 performs the processing shown in FIGS. 6 and 8 based on the reception state information, and the parameters obtained as a result (the coding rate in the error correction coding circuit 109, the modulation scheme in the modulation circuit 107, the first The first wireless communication apparatus may be notified of adaptive control information including parameters such as spreading factor, number of transmission antennas, and transmission power in the code multiplication circuit 106. In this case, the control unit 2 of the first wireless communication device adaptively controls the above-described units of the transmission unit 1 according to the adaptive control information notified from the second wireless communication device.

  As described above, according to the first embodiment, in the receiving unit 6 of the second wireless communication apparatus, a plurality of transmission antennas for the first wireless communication apparatus and a plurality of reception antennas for the second wireless communication apparatus are provided. A known symbol signal is extracted from each received signal propagated through (for example, four) propagation paths. Then, using the known symbol signal corresponding to each extracted propagation path, the magnitude of interference received by each signal transmitted from each transmitting antenna (the magnitude of interference caused by code division multiplexing (SINR)), And the magnitude of interference between signals transmitted from the respective transmitting antennas (the magnitude of interference caused by space division multiplexing (spatial correlation)) are respectively measured, and the control unit 2 of the first wireless communication apparatus or the second Notify the control unit 5 of the wireless communication apparatus. The control unit 2 or the control unit 5 uses the notified interference magnitude (SINR) due to code division multiplexing and interference magnitude (spatial correlation) due to space division multiplexing to cause the spatial division multiplexing. When the interference is large, the number of transmission antennas is reduced, the SINR value that is increased correspondingly is estimated, and the spreading factor is determined based on the estimated SINR. When the interference due to space division multiplexing is small, the number of transmission antennas is increased and the spreading factor is determined based on the notified SINR value.

  As a result, the first radio communication apparatus determines the optimum number of transmission antennas and spreading factor that can reduce interference caused by space division multiplexing and interference caused by code division multiplexing and suppress the reduction in transmission rate as much as possible. can do. Further, the magnitude of interference received by each transmission signal code-spread with the determined spreading factor and transmitted by the determined number of transmission antennas is estimated, and based on the estimated magnitude of interference (FIG. 7). Modulation scheme and coding rate can be determined.

(Second Embodiment)
Next, a second embodiment will be described.

  FIG. 9 shows another configuration example of the first wireless communication apparatus, and FIG. 10 shows another configuration example of the second wireless communication apparatus.

  In FIG. 9, the first wireless communication apparatus includes a transmission unit 7, a control unit 8, and a reception unit 9. In addition, in the transmission part 7 of FIG. 9, the same code | symbol is attached | subjected to the same part as the transmission part 1 of FIG. In the transmission unit 7 of FIG. 9, the pilot insertion circuit 104 of the transmission unit 1 of FIG. 1 is replaced with a pilot insertion circuit 904. The configuration of the receiving unit 9 in FIG. 9 is the same as that of the receiving unit 3 in FIG. 9 is different from the processing operation of the control unit 2 in FIG.

  In FIG. 10, the second wireless communication apparatus includes a transmission unit 10, a control unit 11, and a reception unit 12. In the receiving unit 12 in FIG. 10, the same parts as those in the receiving unit 6 in FIG. 10, the transmission path estimation circuit 605, the separation circuit 607, and the reception state measurement circuit 611 of the reception section 6 in FIG. 2 include a transmission path estimation circuit 1205, a separation circuit 1207, and a first reception state measurement circuit 1211. In the receiving unit 12 of FIG. 10, a second reception state measuring circuit 1212 is further added. The configuration of the transmission unit 10 in FIG. 10 is the same as that of the transmission unit 4 in FIG. Further, the processing operation of the control unit 11 in FIG. 10 is different from the processing operation of the control unit 5 in FIG.

  Hereinafter, a different part from 1st Embodiment is demonstrated.

  9 and 10 exemplify a case where the number of space division multiplexing (that is, the number of antennas) is “2” and there are two circuits corresponding to each antenna. However, the present invention is not limited to this case. Any number can be used.

  First, the pilot insertion circuit 904 of the transmission unit 7 in FIG. 9 will be described. Each of the two pilot insertion circuits 904 (904-1, 904-2) corresponding to each antenna, for the input multiplexed signal, a first known symbol sequence having a predetermined signal pattern and a second The known symbol strings are added and output to the corresponding second code multiplication circuit 103.

  FIG. 11 is a diagram for explaining operations of the second code multiplication circuit 103, the pilot insertion circuit 904, the data multiplexing circuit 105, and the first code multiplication circuit 106 in the first wireless communication apparatus of FIG. 9 in more detail. It is.

  In each of pilot insertion circuits 904-1 and 904-2, first and second known symbol sequences (pilot signals) having a pattern as shown in FIG. 11 are stored in advance.

  For example, A is an arbitrary symbol, and a symbol orthogonal to the symbol A is represented as -A. The pilot insertion circuit 904-1 receives the first known symbol sequence having the pattern “A, A, A, A” and “A, −A, A, −A” for the input multiplexed signal. By adding the second known symbol sequence having the pattern, the first and second known symbol sequences are inserted and output to the second code multiplication circuit 103-1. The pilot insertion circuit 904-2 performs a first known symbol sequence having a pattern of “A, A, −A, −A” and “A, −A, A, −A” on the input multiplexed signal. Are added to the second known symbol sequence, and the first and second known symbol sequences are inserted and output to the second code multiplication circuit 103-1.

  The first known symbol sequence added by the pilot insertion circuit 904-1 and the first known symbol sequence added by the pilot insertion circuit 904-2 are any one of the second radio communication apparatuses on the receiving side. It has a pattern that can separate a signal transmitted from each antenna of the second wireless communication apparatus on the transmission side from a signal received by the antenna. That is, the first known symbol sequences added by the pilot insertion circuits 904-1 and 904-2 are such that the signal received by the second wireless communication device is the antenna 101-1 of the first wireless communication device, It is used for identifying which antenna of 101-2 is a signal transmitted.

  The symbol pattern of the second known symbol sequence added by pilot insertion circuit 904-1 is the same as the symbol pattern of the second known symbol sequence added by pilot insertion circuit 904-2. In addition, the symbol pattern of the second known symbol sequence includes the symbol pattern of the first known symbol sequence added by the pilot insertion circuit 904-1 and the first known symbol sequence added by the pilot insertion circuit 904-2. The symbol patterns are orthogonal to each other.

  The first known symbol sequence is used for measurement of desired signal power-to-interference and noise power ratio (SINR) for specifying the magnitude of the interference signal resulting from transmission path estimation and code division multiplexing, and the second known symbol sequence. The symbol string is used for measurement of desired signal power-to-interference and noise power ratio (SINR) for specifying the magnitude of an interference signal caused by space division multiplexing.

  Adding the second known symbol sequence corresponds to the case where there are a plurality of orthogonal codes to be received as described above. Therefore, each of the code multiplication circuit 604, the synthesis circuit 606, and the separation circuit 1207 of the reception unit 12 of FIG. 10 includes the code multiplication circuit 604, the synthesis circuit 606, and the separation circuit 1207 corresponding to the second known symbol sequence.

  Next, the transmission path estimation circuit 1205 of the receiving unit 12 in FIG. 10 will be described. The configuration of the two transmission path estimation circuits 1205-1 and 1205-2 is the same as that of the transmission path estimation circuits 605-1 and 605-2 in FIG.

  Each of the two transmission path estimation circuits 1205 (1205-1, 1205-2) was detected based on the multipath timing notified from each of the two synchronization circuits 603 (603-1, 603-2). For each multipath, transmission path estimation is performed in the same manner as in the first embodiment using the first known symbol sequence (see FIG. 4). When each synchronization circuit 603 detects L multipaths, each transmission path estimation circuit 1205 performs transmission path estimation for each. Each transmission path estimation circuit 1205 outputs the first transmission path estimation result hTS (u) of the transmission path rTS (u) to the first reception state measurement circuit 1211, and the second transmission path estimation result hTS ( u) _AV is output to the synthesis circuit 606, the separation circuit 1207, and the first reception state measurement circuit 1211.

  Here, the operation of the transmission path estimation circuit 1205-1 (605-1 in FIG. 3) that performs transmission path estimation on the signal received by the first antenna 601-1 in FIG. 4 will be described as an example. The pilot insertion circuit 904-1 in the first wireless communication apparatus inserts a known symbol string having a symbol pattern of (A, A, A, A), and the pilot insertion circuit 904-2 (A, A, -A, A known symbol sequence having a symbol pattern of -A) is inserted. Therefore, the addition circuit 704a and the subtraction circuit 704b of the transmission line estimation circuit 1205-1 (605-1 in FIG. 3) in FIG. 4 perform addition and subtraction in units of four symbols. The amplitude adjustment circuits 705a and 705b adjust the amplitude by dividing the addition result by the addition circuit 704a and the subtraction result by the subtraction circuit 704 by “4”.

  That is, when 4 symbols are added by the adder circuit 704a of FIG. 4, the first known symbol sequence transmitted by the first antenna 101-1 is detected as "4A", but the second antenna 101-2 The transmitted first known symbol string is “0” and is not detected. On the other hand, when 4 symbols are subtracted by the subtraction circuit 704b, the first known symbol sequence transmitted by the second antenna 101-2 is detected as “4A”, but transmitted by the first antenna 101-1. The first known symbol string is “0” and is not detected.

  What is output from the amplitude adjustment circuit 705a is transmitted from the first antenna 101-1 of the first wireless communication apparatus and received by the first antenna 601-1 of the second wireless communication apparatus. This is the known symbol signal “A” of the known symbol string. Also, what is output from the amplitude adjustment circuit 705b is transmitted from the first antenna 101-2 of the first wireless communication apparatus and received by the second antenna 601-2 of the second wireless communication apparatus. This is a known symbol signal “A” of one known symbol string.

  As described above, the transmission path estimation circuit 1205a uses the first known symbol sequence extracted from each incoming signal received by the first antenna 601-1 and the second antenna 602-2 of the second wireless communication apparatus. The known symbol signal “A” is output as the first transmission path estimation result of each propagation path.

  In the averaging circuit 706a, when a predetermined number of addition results that have been subjected to amplitude adjustment (that is, the signal of the symbol “A”) are obtained, the addition average is calculated. The addition average of the known symbol signal “A” is the second transmission path estimation result h11 (u) _AV of the propagation path r11 (u). Similarly, the averaging circuit 706b calculates the addition average when a predetermined number of addition results (ie, known symbol signal “A”) that have been subjected to amplitude adjustment are obtained, and the propagation path r21 (u ) Second transmission path estimation result h21 (u) _AV.

  The transmission path estimation circuit 1205-2 uses the first transmission path of the propagation path r12 (u) for the u-th incoming signal received by the antenna 601-2 in the same manner as the transmission path estimation circuit 1205-2. Estimation result h12 (u) and second transmission path estimation result h12 (u) _AV, first transmission path estimation result h22 (u) of propagation path r22 (u), and second transmission path estimation result h22 (u) _AV is calculated.

  Next, the separation circuit 1207 of the receiving unit 12 in FIG. 10 will be described. The separation circuit 1207 receives the signal received by the antenna 601-1 and the signal received by the antenna 601-2 from the synthesis circuit 606, and the second known symbol sequence and the antenna of the signal received by the antenna 601-1. The second known symbol sequence of the signal received at 601-2 is input.

  Based on the input signal received by the antenna 601-1, the signal received by the antenna 601-2, and the notified transmission path estimation value, the separation circuit 1207 spatially The multiplexed signal transmitted from the antenna 101-1 of the first wireless communication apparatus and the signal transmitted from the antenna 101-2 are each separated, and these two signals are output to the demodulation circuit 608.

  The separation circuit 1207 also receives the second known symbol sequence of the signal received by the antenna 601-1 and the second known symbol sequence of the signal received by the antenna 601-2, and the notified transmission path. Based on the estimated values, the signal having the second known symbol sequence transmitted from the antenna 101-1 of the first wireless communication apparatus, which is spatially multiplexed from the two signals, and the antenna 101-2 Are separated from each other, and the two signals are output to the second reception state measuring circuit 1212.

  The first reception state measurement circuit 1211 of the reception unit 12 in FIG. 10 will be described. As shown in FIG. 12, the configuration of the first reception state measurement circuit 1211 is the same as that of FIG. 5 except that the correlation measurement circuit 803 is excluded from the configuration of FIG. The first reception state measurement circuit 1211 outputs the first transmission path estimation result hTS (u) and the second transmission path estimation result hTS (u) of the propagation path rTS (u) output from the transmission path estimation circuit 1205. ) _AV is input.

The first reception state measurement circuit 1211 calculates a desired signal power-to-interference and noise power ratio (SINR_C) indicating the magnitude of an interference signal resulting from code division multiplexing. That is, in the first SINR measurement circuit 802a to the fourth SINR measurement circuit 802a, the transmission path (propagation) between the first antenna 101-1 and the first antenna 601-1 is expressed by using Expression (1). SINR_C ₁₁ in the path), SINR_C ₁₂ in the transmission path (propagation path) between the first antenna 101-1 and the second antenna 601-2, the second antenna 101-2 and the first antenna 601-1 SINR_C ₂₁ in the transmission path (propagation path) between the second antenna 101-2 and SINR_C ₂₂ in the transmission path (propagation path) between the second antenna 101-2 and the second antenna 601-2.

  The averaging circuit 804 calculates the average of these interference signals, that is, the magnitude of the interference signal resulting from code division multiplexing of the transmission path (propagation path) between the first wireless communication apparatus and the second wireless communication apparatus. The indicated SINR_C is calculated.

SINR_C ₁₁ , SINR_C ₁₂ , SINR_C ₂₁ , and SINR_C ₂₂ are output to the control unit 11 together with SINR_C calculated by the averaging circuit 804 or SINR_C.

  Next, the second reception state measurement circuit 1212 of the reception unit 12 in FIG. 10 will be described. The second reception state measurement circuit 1212 receives the second known signal extracted from the antenna 101-1 of the first wireless communication device (received by the second wireless communication device) extracted by the separation circuit 1207. A signal p (1) having a symbol string and a signal p (2) having a second known symbol string transmitted from the antenna 101-2 are input. The second reception state measurement circuit 1212 uses these two signals p (1) and p (p) to measure desired signal power versus interference and noise for measuring the magnitude of the interference signal caused by space division multiplexing. The power ratio (SINR_S) is measured, and the obtained SINR_S is output to the control unit 11.

  A configuration example of the second reception state measurement circuit 1212 is shown in FIG.

  In FIG. 13, the first SINR measurement circuit 1212a receives the signal p (1) having the second known symbol sequence transmitted from the antenna 101-1 of the first wireless communication apparatus, and this signal p ( From 1), the desired signal power to interference and noise power ratio SINR_Sp (1) is calculated.

  The second SINR measurement circuit 1212b receives a signal p (2) having a second known symbol sequence transmitted from the antenna 101-2 of the first wireless communication apparatus. From this signal p (2), Calculate desired signal power versus interference and noise power ratio SINR_Sp (2).

  The averaging circuit 1212c calculates the addition average of SINR_Sp (1) and SINR_Sp (2), and outputs the obtained SINR_S to the control unit 11.

  The control unit 11 outputs the SINR_Sp (1) and the SINR_Sp (2) obtained by the first and second SINR measurement circuits 1212a and 1212b to the control unit 11 together with the SINR_S output from the averaging circuit 1212c. Also good.

  The SINR_C calculated by the first reception state measurement circuit 1211 can be used to specify the magnitude of an interference signal caused by code division multiplexing, and the SINR_S calculated by the second reception state measurement circuit 1212 Can be used to specify the magnitude of the interference signal resulting from space division multiplexing. Therefore, the control unit 11 notifies the first wireless communication device of the reception state information including SINR_C and SINR_S notified from the first and second reception state measurement circuits 1211 and 1212, so that the first wireless communication device Then, even when there are interference signals of different factors, adaptive control can be performed according to the respective sizes.

  The greater the difference between SINR_C and SINR_S, the greater the interference is due to space division multiplexing in the second wireless communication apparatus. The smaller the difference between SINR_C and SINR_S, the more This is a reception state in which interference caused by multiplexing is small. In addition, the smaller the SINR_C value, the larger the interference caused by code division multiplexing in the second wireless communication apparatus, and the larger the SINR_C value, the more the second wireless communication apparatus performs code division multiplexing. This is a reception state in which the resulting interference is small.

  Further, in order to reduce interference caused by space division multiplexing, the number of transmission antennas is reduced, and in order to reduce interference caused by code division multiplexing, the spreading factor may be increased.

  With reference to the flowcharts shown in FIGS. 14 and 15, the operation of the control unit 8 in the first wireless communication apparatus in FIG. 9 will be described in detail. Here, a case where the number of antennas in the transmission unit 7 of the first wireless communication apparatus is “2” and the PSF is “256” will be described as an example.

  FIG. 14 is a flowchart for explaining the outline of the operation of the control unit 8. When the control unit 8 starts communication with the second wireless communication apparatus, the control unit 8 determines the spreading factor (SF) and the number of multiplexed data from the communication quality requested by the second wireless communication apparatus (Step S8). S101). Then, taking into account the relationship between the determined spreading factor and the number of multiplexed data, in order to determine the modulation scheme and coding rate from the SINR notified from the second wireless communication terminal, the optimum SINR, modulation scheme (Mod ), A table M as shown in FIG. 7 showing the combination of coding rates (R) is created (step S102). In the case of the second embodiment, the item “SINR” in FIG. 7 is “SINR_S”. Here, a case where the spreading factor is determined to be “16” and the data multiplexing number is determined to be “1” will be described as an example.

  Thereafter, the control unit 8 periodically checks whether the reception state information is notified from the second wireless communication device (step S103).

  When the reception state information is notified, the number of antennas to be transmitted is determined using SINR_C and SINR_S included in the reception state information (step S4).

  Specifically, when the difference between SINR_C and SINR_S is larger than a predetermined threshold (Dth), the process proceeds to step S105, and the number of antennas to be transmitted is set to “1”. Accordingly, the transmission power is increased by the amount that the number of antennas used for transmission is reduced. For example, here, assuming that transmission power of each antenna when transmitting using two antennas is P, it is 2P when transmitting using one antenna.

  On the other hand, if the difference between SINR_C and SINR_S is equal to or smaller than the predetermined threshold (Dth) in step S104, the process proceeds to step S108, and the number of antennas used for transmission is set to “2”. Accordingly, the transmission power at each antenna is set to P, and the process proceeds to step S109.

  If it is determined in step S105 that the number of antennas used for transmission is “1”, the process proceeds to step S106, and antennas used for transmission are selected. In this case, in this case, when the reception state information notified from the second wireless communication device includes SINR_S (SINR_Sp (1), SINR_Sp (2)) obtained for each transmission antenna, antennas 101-1 and 1010-2 are used. Of these, the antenna with the larger SINR_S is selected.

  As the transmission power at each antenna is increased in step S105, the subsequent SINR_S is expected to increase. Accordingly, the process proceeds to step S107, and the value of SINR_S notified by the reception state information is increased by increasing the transmission power, and the process proceeds to step S109.

  In step S109, when SINR_S included in the reception state information or SINR_S is corrected in step S107, a spreading factor determination process as shown in FIG. 15 is performed using the corrected SINR_S.

  In FIG. 15, first, when the SINR_S included in the reception state information is corrected in step S121 or the SINR_S is corrected in step S107, the corrected SINR_S is compared with a predetermined threshold Cthmin, and the SINR_S is compared with the threshold Cthmin. Is smaller than that, it is determined that interference due to code division multiplexing is large, and the process proceeds to step S122.

  In step S122, the spreading factor is increased, and the value of SINR_S is increased by the amount corresponding to the increased spreading factor. For example, the spreading factor (SF) is doubled and the SINR_S is corrected to be increased by “3 dB”. And it returns to step S121 again and repeats the process of step S122 until this corrected SINR_S becomes more than threshold value Cthmin.

  Here, the threshold value Cthmin is set smaller than the minimum SINR_S on the table M in FIG. That is, when SINR_S becomes small enough to deviate from a predetermined range, the reception state is improved by increasing the spreading factor and increasing the gain by spreading. At this time, the maximum value of the spreading factor is PSF.

  If SINR_S is greater than or equal to the threshold value Cthmin in step S121, the process proceeds to step S123. In step S123, SINR_S is compared with a predetermined threshold Cthmax. If SINR_S is larger than threshold Cthmax, the process proceeds to step S124.

  In step S124, the spreading factor (SF) is lowered, and the SINR value is reduced by the amount that the spreading factor is lowered. For example, the spreading factor is ½ and SINR_S is reduced by “3 dB”. And it returns to step S123 again and repeats the process of step S124 until this corrected SINR_S becomes smaller than the threshold value Cthmax.

  Here, the threshold value Cthmax is set larger than the maximum SINR on the table M in FIG. That is, when the SINR increases to the extent that it deviates from the predetermined range, the transmission rate is improved by reducing the spreading factor. At this time, the minimum value of the spreading factor is arbitrarily determined.

  Returning to the description of FIG. As described above, the SINR_S notified by the reception state information is corrected by the process (FIGS. 14 and 15) for determining the number of transmission antennas and the spreading factor. Therefore, in step S110, the optimal modulation scheme and coding rate corresponding to the corrected (estimated) SINR_S value are determined with reference to the table M in FIG. Note that the processes in steps S103 to S110 are continuously performed while the first wireless communication device and the second wireless communication device are communicating (step S111).

  The control unit 2 of the first wireless communication apparatus performs the processing shown in FIGS. 14 and 15 on the basis of the reception state information transmitted from the second wireless communication apparatus, so that the second wireless communication apparatus On the other hand, parameters such as a coding rate in the error correction coding circuit 109, a modulation scheme in the modulation circuit 107, a spreading factor in the first code multiplication circuit 106, the number of transmission antennas, transmission power, etc. are determined, Are controlled (adaptive control) to operate according to the determined parameters.

  In the above description, the control unit 8 of the first wireless communication device performs adaptive control based on the reception state information notified from the second wireless communication device. The control unit 11 performs the processing shown in FIGS. 14 and 15 based on the reception state information, and the parameters obtained as a result (the coding rate in the error correction coding circuit 109, the modulation scheme in the modulation circuit 107, the first The first wireless communication apparatus may be notified of adaptive control information including parameters such as spreading factor, number of transmission antennas, and transmission power in the code multiplication circuit 106. In this case, the control unit 8 of the first wireless communication device adaptively controls the above-described units of the transmission unit 7 according to the adaptive control information notified from the second wireless communication device.

  As described above, according to the second embodiment, in the receiving unit 12 of the second wireless communication apparatus, the magnitude of interference (SINR_C) caused by code division multiplexing and the interference caused by space division multiplexing are obtained. Each size (SINR_S) is measured and notified to the control unit 8 of the first wireless communication apparatus or the control unit 11 of the second wireless communication apparatus. In the control unit 8 or the control unit 11, the difference between the notified interference magnitude (SINR_C) caused by code division multiplexing and the interference magnitude (SINR_S) caused by space division multiplexing is determined based on a predetermined threshold Dth. If larger, the number of transmission antennas is reduced, the SINR_S value that is increased by that amount is estimated, and the spreading factor is determined based on the estimated SINR_S. When the difference is equal to or smaller than the threshold value Dth, the number of transmission antennas is increased (or the maximum number of transmission antennas is determined), and the spreading factor is determined based on the notified SINR value.

  As a result, the first radio communication apparatus determines the optimum number of transmission antennas and spreading factor that can reduce interference caused by space division multiplexing and interference caused by code division multiplexing and suppress the reduction in transmission rate as much as possible. can do. Further, the magnitude of interference received by each transmission signal code-spread with the determined spreading factor and transmitted by the determined number of transmission antennas is estimated, and based on the estimated magnitude of interference (FIG. 7). Modulation scheme and coding rate can be determined.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure which shows the structural example of the 1st radio | wireless communication apparatus which concerns on 1st Embodiment. The figure which shows the structural example of the 2nd radio | wireless communication apparatus which concerns on 1st Embodiment. The figure for demonstrating operation | movement of the principal part of a 1st radio | wireless communication apparatus. The figure which shows the structural example of the transmission-line estimation circuit of a 2nd radio | wireless communication apparatus. The figure which shows the structural example of the receiving condition measuring circuit of a 2nd radio | wireless communication apparatus. The flowchart for demonstrating operation | movement of the control part of a 1st radio | wireless communication apparatus. The figure which shows an example of the table for determining a modulation system and a code rate from SINR. The flowchart for demonstrating the spreading factor determination process of the control part of a 1st radio | wireless communication apparatus. The figure which shows the structural example of the 1st radio | wireless communication apparatus which concerns on 2nd Embodiment. The figure which shows the structural example of the 2nd radio | wireless communication apparatus which concerns on 2nd Embodiment. The figure for demonstrating operation | movement of the principal part of a 1st radio | wireless communication apparatus. The figure which shows the structural example of the 1st receiving condition measuring circuit of a 2nd radio | wireless communication apparatus. The figure which shows the structural example of the 2nd receiving condition measuring circuit of a 2nd radio | wireless communication apparatus. The flowchart for demonstrating operation | movement of the control part of a 1st radio | wireless communication apparatus. The flowchart for demonstrating the spreading factor determination process of the control part of a 1st radio | wireless communication apparatus. The figure for demonstrating the interference resulting from code division multiplexing, and the interference resulting from space division multiplexing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmission part, 2 ... Control part, 3 ... Reception part, 101 ... Antenna, 102 ... Radio processing circuit, 103 ... 2nd code multiplication circuit 103, 104 ... Pilot insertion circuit, 105 ... Data multiplexing circuit, 106 ... 1st DESCRIPTION OF SYMBOLS 1 code multiplication circuit, 107 ... Modulation circuit, 108 ... S / P circuit, 109 ... Error correction coding circuit, 110 ... Data distribution circuit, 4 ... Transmission part, 5 ... Control part, 6 ... Reception part, 601 ... Antenna , 602 ... Wireless processing circuit, 603 ... Synchronization circuit, 604 ... Sign multiplication circuit, 605 ... Transmission path estimation circuit, 606 ... Synthesis circuit, 607 ... Separation circuit, 608 ... Demodulation circuit, 609 ... P / S circuit, 610 ... Error Correction decoding circuit, 611... Reception state measuring circuit.

Claims (19)

Multiple antennas,
Encoding means for error-correcting encoded transmission data to generate error correction encoded data;
Modulating means for modulating the error correction encoded data to generate a modulated signal;
Spreading means for code spreading the modulated signal using a spreading code to generate a code spread signal;
Means for dividing the code spread signal into the number of transmission antennas used for transmission among the plurality of antennas, and generating each signal corresponding to each transmission antenna;
Means for inserting a known symbol sequence for identifying a transmission antenna to which the signal is transmitted into each signal corresponding to each transmission antenna, and generating each transmission signal corresponding to each transmission antenna;
Transmission means for transmitting each transmission signal from each transmission antenna;
Receiving means for receiving reception state information including the magnitude of interference between each transmission signal transmitted from each transmission antenna and the magnitude of interference received by each transmission signal;
Control means for determining an adaptive control parameter including the number of transmission antennas and a spreading factor when code spreading is performed by the spreading means based on the reception state information;
A wireless communication apparatus comprising:   The radio communication apparatus according to claim 1, wherein the magnitude of interference between the transmission signals and the magnitude of interference received by the transmission signals are measured based on the known symbol sequence. The adaptive control parameter further includes a coding rate in the coding unit, a modulation scheme in the modulation unit,
The control means estimates the magnitude of interference received by each transmission signal code-spread with the determined spreading factor and transmitted by the determined number of transmitting antennas, and based on the estimated magnitude of interference. The wireless communication apparatus according to claim 1, wherein the coding rate and the modulation method are determined.   2. The wireless communication apparatus according to claim 1, wherein the known symbol sequences inserted in the signals corresponding to the transmission antennas are orthogonal to each other. The control means includes
When the magnitude of interference between the transmission signals is greater than a predetermined threshold, the number of transmission antennas is reduced by a predetermined number, and accordingly, the transmission power at each transmission antenna is increased by a predetermined value 2. The wireless communication according to claim 1, wherein a magnitude of interference received by each transmission signal is estimated, and the spreading factor is determined based on the estimated magnitude of interference received by each transmission signal. apparatus. Multiple antennas,
Encoding means for error-correcting encoded transmission data to generate error correction encoded data;
Modulating means for modulating the error correction encoded data to generate a modulated signal;
Spreading means for code spreading the modulated signal using a spreading code to generate a code spread signal;
Means for dividing the code spread signal into the number of transmission antennas out of the plurality of antennas to generate a signal corresponding to each transmission antenna;
Inserting in each signal corresponding to each transmission antenna a first known symbol sequence for identifying the antenna to which the signal is transmitted and a second known symbol sequence orthogonal to the first known symbol sequence Means for generating each transmission signal corresponding to each transmission antenna;
Transmission means for transmitting each transmission signal from each transmission antenna;
Receiving means for receiving reception state information including the magnitude of interference between transmission signals transmitted from each transmission antenna and the magnitude of interference received by each transmission signal;
Control means for determining an adaptive control parameter including the number of transmission antennas and a spreading factor when code spreading is performed by the spreading means based on the reception state information;
A wireless communication apparatus comprising:   7. The radio communication apparatus according to claim 6, wherein the magnitude of interference between each transmission signal and the magnitude of interference received by each transmission signal are measured based on the first and second known symbol sequences. . The adaptive control parameter includes a coding rate in the coding unit, a modulation scheme in the modulation unit,
The control means estimates the magnitude of interference received by each transmission signal code-spread with the determined spreading factor and transmitted by the determined number of transmitting antennas, and based on the estimated magnitude of interference. The wireless communication apparatus according to claim 6, wherein the coding rate and the modulation scheme are determined.   7. The wireless communication apparatus according to claim 6, wherein the first known symbol sequences inserted in the signals corresponding to the transmission antennas are orthogonal to each other.   The radio communication apparatus according to claim 9, wherein the second known symbol sequence inserted in each signal corresponding to each transmission antenna is orthogonal to each of the first known symbol sequences. The control means includes
When the difference between the magnitude of interference received by each transmission signal and the magnitude of interference between the transmission signals is larger than a predetermined threshold, the number of transmission antennas is reduced by a predetermined number, and accordingly, Estimate the magnitude of interference between the transmission signals when the transmission power is increased by a predetermined value, and determine the spreading factor based on the estimated magnitude of interference between the transmission signals. The wireless communication apparatus according to claim 6. Multiple receive antennas;
Receiving means for receiving each radio signal including a known symbol sequence for identifying a plurality of transmitting antennas at each receiving antenna;
Extraction means for extracting each known symbol signal corresponding to each propagation path specified by the reception antenna and the transmission antenna from each radio signal based on the known symbol sequence;
Measuring means for measuring the magnitude of interference between each known symbol signal and the magnitude of interference received by each known symbol signal;
Transmitting means for transmitting reception state information including the magnitude of interference between each known symbol signal and the magnitude of interference received by each known symbol signal;
A wireless communication apparatus comprising:   13. The wireless communication according to claim 12, wherein the extraction unit extracts each known symbol signal corresponding to each propagation path by adding and subtracting each known symbol of the known symbol sequence of the radio signal. apparatus. The measuring means includes
Means for obtaining a correlation coefficient between the respective known symbol signals indicating the magnitude of interference between the respective known symbol signals;
Means for determining the SINR (Signal-to-interference and Noise power Ratio) of each known symbol signal indicating the magnitude of interference received by each known symbol signal;
The wireless communication apparatus according to claim 12, further comprising: Multiple receive antennas;
Receiving means for receiving, at each receiving antenna, a radio signal including a first known symbol sequence for identifying a plurality of transmitting antennas and a second known symbol sequence orthogonal to the first known symbol sequence;
First extraction means for extracting each first known symbol signal corresponding to each propagation path specified by the reception antenna and the transmission antenna from each radio signal based on the first known symbol sequence;
First measuring means for measuring the magnitude of interference experienced by each first known symbol signal;
Second extraction means for extracting each second known symbol signal corresponding to each transmission antenna based on the second known symbol sequence;
Second measuring means for measuring the magnitude of interference experienced by each second known symbol signal;
Transmitting means for transmitting reception state information including a magnitude of interference received by each of the first known symbol signals and a magnitude of interference received by each of the second known symbol signals;
A wireless communication apparatus comprising:   The first extraction means extracts each known symbol signal corresponding to each propagation path by adding and subtracting each known symbol of the first known symbol sequence of the radio signal. Item 15. A wireless communication device according to Item 15. The first measuring means obtains an SINR (Signal-to-interference and Noise power Ratio) of each of the first known symbol signals,
16. The wireless communication apparatus according to claim 15, wherein the second measuring unit obtains SINR of each of the second known symbol signals. In an adaptive control method for performing communication between a transmission device including a plurality of antennas and a reception device including a plurality of reception antennas,
The transmitting apparatus code-spreads the modulated signal using a spreading code, divides the number into the number of transmitting antennas used for transmission among the plurality of antennas, and generates each signal corresponding to each transmitting antenna;
The transmitter inserts a known symbol sequence for identifying a transmission antenna to which the signal is transmitted into each signal corresponding to each transmission antenna;
The transmitting device transmitting a signal with a known symbol inserted from each transmitting antenna;
Receiving the signal transmitted from each transmitting antenna by each receiving antenna;
The receiving apparatus adds and subtracts each known symbol of the known symbol sequence, thereby causing each known signal corresponding to each propagation path specified by the combination of the receiving antenna and the transmitting antenna from each received signal. An extraction step for extracting a symbol signal;
A measuring step in which the receiver measures the magnitude of interference between the known symbol signals and the magnitude of interference received by each known symbol signal;
A transmission step in which the receiving apparatus transmits reception state information including the magnitude of interference between the known symbol signals and the magnitude of interference received by the known symbol signals;
The transmitting device receiving the reception status information;
The transmitter determines, based on the reception state information, the number of the transmission antennas and a spreading factor for code spreading;
An adaptive control method comprising: In an adaptive control method for performing communication between a transmission device including a plurality of antennas and a reception device including a plurality of reception antennas,
The transmitting apparatus code-spreads the modulated signal using a spreading code, divides the number into the number of transmitting antennas used for transmission among the plurality of antennas, and generates each signal corresponding to each transmitting antenna;
A first known symbol sequence for identifying the antenna to which the signal is transmitted, and a second known symbol orthogonal to the first known symbol sequence for each signal corresponding to each transmission antenna Inserting a column;
The transmitting apparatus transmitting the signal in which the first and second known symbols are inserted from each transmitting antenna;
Receiving the signal transmitted from each transmitting antenna by each receiving antenna;
The receiving apparatus adds and subtracts each known symbol of the first known symbol string, thereby each corresponding to each propagation path specified from the receiving antenna and the transmitting antenna from each received signal. Extracting a first known symbol signal;
Measuring the magnitude of interference received by each first known symbol signal by the receiving device;
The receiving device extracting each second known symbol signal corresponding to each transmitting antenna;
The receiver measures the magnitude of interference experienced by each second known symbol signal;
The receiving apparatus transmitting reception state information including a magnitude of interference received by each of the first known symbol signals and a magnitude of interference received by each of the second known symbol signals;
The transmitting device receiving the reception status information;
The transmitter determines, based on the reception state information, the number of the transmission antennas and a spreading factor for code spreading;
An adaptive control method comprising:

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