JP3998631B2 - Wireless communication system, mobile communication terminal apparatus, base station apparatus, and wireless communication method - Google Patents

Description

  The present invention relates to a mobile communication system, and more particularly to a multicarrier radio communication system that performs communication using a multicarrier radio signal composed of a plurality of subcarrier signals.

  In a conventional mobile communication system, a base station transmits a known signal in a wireless communication area (cell), and a mobile communication terminal belonging to the cell measures an adaptive control parameter from the received known signal and obtains a measurement result. What feeds back to the base station is known. As a result, the base station refers to the fed back adaptive control parameter and performs various adaptive controls in order to maintain the optimum communication state according to the state of the wireless communication path (for example, see Non-Patent Document 1). .

In addition, in a multicarrier mobile communication system that performs radio communication using a plurality of subcarriers, quality information in units of subcarriers such as electric field strength (RSSI) and signal-to-interference power ratio (SIR) are measured as adaptive control parameters. In some cases, the measurement result is fed back to the base station (see, for example, Patent Document 1).
JP-A-2001-268050 (page 22, FIG. 4, page 32, FIG. 21) 3GPP Technical Specification TR25.848v4.0.0 (2001-03) chap.6 TS25.214v3.12.0 (2003-03) chap.5, chap.7

  Thus, in the conventional mobile communication system, it is necessary to measure various adaptive control parameters in the mobile communication terminal. In particular, when adaptive control parameters are measured in units of subcarriers as in a multi-carrier mobile communication system, there are problems that increase the circuit scale of mobile communication terminals and increase power consumption. In addition, considering the small size and low power consumption of mobile communication terminals, when measuring adaptive control parameters with the minimum circuit configuration and signal processing amount, the reliability will be affected. As a result, it becomes difficult to maintain an optimal communication state according to the state of the wireless communication path, and there is a problem that the wireless communication performance is deteriorated.

  Accordingly, the present invention has been made in view of the above problems, and is a closed-loop adaptive control that maintains an optimal communication state according to the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal. An object of the present invention is to provide a mobile communication system that enables the above.

  (1) In a wireless communication system that performs communication using a multicarrier signal including a plurality of subcarrier signals between a base station and a terminal, the terminal transmits a data signal transmitted from the base station to the plurality of subcarrier signals. All of the carrier signals or a part of the subcarrier signals are transmitted to the base station, and the base station communicates with the terminal based on the degree of deterioration of the signal power of the data signal returned from the terminal. At least one of the types of modulation schemes used for communication, the coding rate, and the parameter values for adjusting the transmission power is determined.

  In a wireless communication system in which communication is performed using a multicarrier signal including a plurality of subcarrier signals between a base station and a terminal, the terminal transmits a data signal transmitted from the base station to the plurality of subcarrier signals. All or part of the subcarrier signals are transmitted to the base station, and the base station has a plurality of antennas for transmitting and receiving the multicarrier signals, and from the multicarrier signals received by the plurality of antennas Based on the amplitude or phase of the extracted data signal, a transmission weight for each of the plurality of antennas is determined.

  (2) A mobile communication terminal apparatus that communicates with a base station using a multicarrier signal including a plurality of subcarrier signals, the mobile communication terminal apparatus uses the plurality of subcarrier signals of the received radio signal, As a signal for measuring the state of the transmission path between the mobile communication terminal device and the base station and the degree of signal power degradation at the base station. The extracted data signal is transmitted to the base station.

  A mobile communication terminal apparatus that communicates with a base station using a multicarrier signal composed of a plurality of subcarrier signals, the mobile communication terminal and the base station from the plurality of subcarrier signals of the received multicarrier signal A known data signal is extracted with a station, and the signal is received as a signal for measuring the state of the transmission path between the mobile communication terminal apparatus and the base station and the degree of signal power degradation at the base station. Means for transmitting the difference between the data signal extracted from the multi-carrier signal received this time and the data signal extracted from the multi-carrier signal previously received by the receiving means.

  (3) A base station apparatus that communicates with a terminal using a multicarrier signal composed of a plurality of subcarrier signals, the terminal and the base station apparatus transmitted from the base station apparatus and returned from the terminal Of the modulation method used for communication with the terminal, the coding rate, and the parameter value for adjusting the transmission power based on the degree of degradation of the signal power of the known data signal Determine at least one.

  In addition, a base station apparatus that performs communication with a terminal using a multicarrier signal including a plurality of subcarrier signals has a plurality of antennas that transmit and receive the multicarrier signal, and has received the plurality of antennas. A known data signal between the terminal and the base station apparatus, which is transmitted from the base station apparatus and returned from the terminal, is extracted from the multicarrier signal, and based on the amplitude or phase of the extracted data signal. And determining a transmission weight for each of the plurality of antennas.

  According to the present invention, an optimal communication state according to the state of the wireless transmission path between the terminal and the base station and the degree of deterioration of the signal power is maintained without increasing the circuit scale and power consumption on the terminal side. be able to.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 schematically shows a basic configuration example of a mobile communication system according to the present invention, which is roughly composed of a mobile communication terminal 100, a base station 120, and a radio communication path 140. The wireless communication path 140 has a characteristic that its wireless propagation characteristic changes with time according to changes in the surrounding environment.

  The mobile communication terminal 100 includes an antenna 101, a radio processing unit 102, a reception processing unit 103, a decoding processing unit 104, a reception buffer 105, a base signal extraction unit 106, a closed loop control unit 107, a transmission buffer 108, an encoding processing unit 109, a transmission A processing unit 110 and a controller 111 are included.

  The antenna 101 receives a radio signal having a predetermined frequency and outputs it to the radio processing unit 102. The radio processing unit 102 performs band limitation on the input radio signal, further performs predetermined radio processing such as down-conversion, quadrature demodulation, and A / D conversion, and outputs a baseband digital signal to the reception processing unit 103. .

  The reception processing unit 103 performs predetermined reception processing such as synchronization processing and demodulation processing on the input baseband digital signal, and outputs the demodulation results to the known signal extraction unit 106 and the decoding processing unit 104, respectively. The decoding processing unit 104 performs predetermined decoding processing on the input demodulation result, for example, turbo decoding or Viterbi decoding, and outputs the decoding result to the reception buffer 105. The reception buffer 105 outputs the input decoding result to the controller 111 at a predetermined timing.

  The known signal extraction unit 106 extracts a known signal transmitted from the base station 120 from the signal output from the reception processing unit 103. Here, the known signal is a data signal (for example, a pilot signal) uniquely determined in the mobile communication system, and its signal pattern and transmission timing from the base station are known between the base station (system) and the terminal. Signal. The closed loop control unit 107 controls to extract the extracted known signal to the encoding processing unit 109 or the transmission processing unit 110. At this time, the closed loop control unit 107 can perform a reduction process or the like described later on the extracted known signal. The output destination can be arbitrarily selected.

  The transmission buffer 108 outputs the transmission data input from the controller 111 to the encoding processing unit 109 at a predetermined timing. The encoding processing unit 109 performs a predetermined encoding process such as turbo encoding or convolutional encoding on the input transmission data and the extracted known signal, and outputs the result to the transmission processing unit 110.

  The transmission processing unit 110 performs predetermined transmission processing such as modulation processing on the input encoded data and the extracted known signal, and outputs the result to the wireless processing unit 102. The wireless processing unit 102 performs D / A conversion on the input transmission signal, performs predetermined wireless processing such as orthogonal modulation, up-conversion, and band limitation, and outputs the result to the antenna 101. The antenna 101 transmits a radio signal input at a predetermined frequency.

  The base station 120 includes an antenna 121, a radio processing unit 122, a reception processing unit 123, a decoding processing unit 124, a reception buffer 125, a closed loop information extraction unit 126, a measurement unit 127, an adaptive control processing unit 128, a transmission buffer 129, and an encoding process. Section 130, transmission processing section 132, base signal insertion section 131, and controller 133.

  The antenna 121 receives a radio signal having a predetermined frequency and outputs it to the radio processing unit 122. The radio processing unit 122 performs band limitation on the input radio signal, performs predetermined radio processing such as down-conversion, quadrature demodulation, and A / D conversion, and outputs a baseband digital signal to the reception processing unit 123. .

  The reception processing unit 123 performs predetermined reception processing such as synchronization processing and demodulation processing on the input baseband digital signal, and outputs a demodulation result to the decoding processing unit 124. The decoding processing unit 124 performs predetermined decoding processing on the input demodulation result, for example, turbo decoding or Viterbi decoding, and outputs the decoding result to the reception buffer 125. The reception buffer 125 outputs the input decoding result to the controller 133 at a predetermined timing.

  On the other hand, the demodulation result of the baseband digital signal by the reception processing unit 123 is also output to the closed loop information extraction unit 126.

  The closed-loop information extraction unit 126 extracts a known signal returned from the mobile communication terminal 100 from the signal output from the reception processing unit 123 and outputs it to the measurement unit 127. The measuring unit 127 measures the channel characteristics between the base station 120 and the mobile communication terminal 100 and the degree of signal power degradation (quality characteristics) based on the input known signal, and the result is an adaptive control process. To the unit 128.

  The adaptive control processing unit 128 controls the transmission processing unit 132 and the radio processing unit 122 to perform predetermined adaptive control represented by adaptive modulation and transmission power control using the input quality characteristics and channel characteristics. .

  The transmission buffer 129 outputs the transmission data input from the controller 133 to the encoding processing unit 130 at a predetermined timing. The encoding processing unit 130 performs predetermined encoding processing such as turbo encoding or convolutional encoding on the input transmission data, and outputs the result to the transmission processing unit 132. Also, the known signal insertion unit 131 outputs a known signal having a predetermined format to the transmission processing unit 132. The known signal is inserted into, for example, a preamble in a frame of a predetermined format transmitted from the base station 120 to the mobile communication terminal 100.

  The transmission processing unit 132 creates a frame of a predetermined format from the input encoded data and a known signal. The known signal is inserted at a predetermined position in the preamble of the frame, for example. The transmission processing unit 132 performs predetermined transmission processing such as modulation processing on the created frame in accordance with predetermined adaptive control controlled by the adaptive control processing unit 128, and outputs the result to the wireless processing unit 122. The radio processing unit 122 performs D / A conversion on the input transmission signal, performs predetermined radio processing such as orthogonal modulation, up-conversion, and band limitation, and outputs the result to the antenna 121. The antenna 121 transmits a radio signal input at a predetermined frequency.

  With such a configuration, the base station 120 inserts the known signal into a predetermined frame and transmits it to the mobile communication terminal 100, and the mobile communication terminal 100 receives the known signal in the frame. The mobile communication terminal 100 inserts the received known signal into a frame to be transmitted to the base station 120 and transmits the frame to the base station 120. The base station 120 receives the frame transmitted from the mobile communication terminal 100, and based on the known signal returned from the mobile communication terminal 100 in the frame, the channel characteristics (between the mobile communication terminal 100 and the base station 120 ( For example, closed loop adaptive control is performed by measuring amplitude characteristics, phase characteristics, etc.) and reception quality characteristics at the mobile communication terminal 100 (signal to interference power ratio (SIR), interference, noise power ratio (SINR), etc.). . This means that the base station 120 measures the adaptive control parameters (such as channel characteristics and reception quality identification) that have been measured on the mobile communication terminal side, and as a result, the adaptive control parameters of the mobile communication terminal 100 It is possible to provide a mobile communication system that performs various closed-loop adaptive controls that maintain an optimal communication state according to the state of a wireless communication path without increasing the circuit scale and power consumption required for measurement.

  1 is a multicarrier signal (broadband radio signal) composed of a plurality of subcarrier signals such as OFDM (orthogonal frequency division multiplexing) and OFCDM (orthogonal frequency and code division multiplexing). In the case of a multi-carrier mobile communication system using, a plurality of subcarriers or some of them are used for communication between the mobile communication terminal 100 and the base station 120.

  In this case, the base station 120 inserts the known signal into a predetermined frame, puts the known signal on a plurality of subcarrier signals, and transmits it to the mobile communication terminal 100. When the mobile communication terminal 100 receives a wideband radio signal composed of a plurality of subcarrier signals, a known signal in a frame transmitted by each subcarrier signal is extracted. Mobile communication terminal 100 inserts the extracted known signal into a frame to be transmitted to base station 120, places it on a plurality of subcarrier signals, and transmits it to base station 120. The base station 120 extracts a known signal returned from the mobile communication terminal 100 from the subcarrier signal transmitted from the mobile communication terminal 100, and a communication path between the mobile communication terminal 100 and the base station 120 from the known signal. By measuring characteristics (for example, amplitude characteristics, phase characteristics, etc.) and reception quality characteristics (signal-to-interference power ratio (SIR), interference, noise power ratio (SINR), etc.) at mobile communication terminal 100, base station 120 And closed-loop adaptive control between the mobile communication terminal 100 and the mobile communication terminal 100. This means that the base station 120 measures adaptive control parameters (such as channel characteristics and reception quality identification) that are conventionally measured on the mobile communication terminal side. As a result, a plurality of subcarriers in the mobile communication terminal 100 are measured. Provided is a mobile communication system that performs various closed-loop adaptive controls that maintain an optimal communication state according to the state of a wireless communication path without increasing the circuit scale and power consumption required for measuring adaptive control parameters It becomes possible.

  (1) Next, the closed loop adaptive control in the base station 120 will be specifically described.

(First example)
As a first example of closed loop adaptive control, a reception quality characteristic is measured from a known signal returned from the mobile communication terminal 100, and communication between the base station 120 and the mobile communication terminal 100 is performed based on the measurement result. A case where the modulation scheme and coding rate to be used are determined will be described. A configuration example of the base station 120 in this case is shown in FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and only different parts will be described. That is, in FIG. 2, the measurement unit 127 and the adaptive control processing unit 128 of FIG. 1 are a quality measurement unit 201 and an AMC (Adaptive Modulation Coding) determination unit 202, respectively.

  The closed loop information extraction unit 126 extracts a known signal transmitted from the mobile communication terminal 100 from the demodulation result for the baseband digital signal obtained by the reception processing unit 123 and outputs it to the quality measurement unit 201.

  The quality measurement unit 201 uses a signal-to-interference power ratio (SIR), a signal-to-interference ratio, a noise power ratio (SINR), and the like representing the degree of signal degradation as reception quality characteristics at the mobile communication terminal 100 from the input known signal. Measure and output the measurement result to the AMC determination unit 202. The AMC determination unit 202 determines a modulation method, a coding rate, and the like based on the input quality characteristic measurement value, and outputs the result to the coding processing unit 130 and the transmission processing unit 132. The encoding processing unit 130 encodes the transmission data according to the coding rate determined by the AMC determining unit 202, and the transmission processing unit 132 modulates the encoded data according to the modulation scheme determined by the AMC determining unit 202.

  Note that SIR and SINR are substantially synonymous and represent the ratio of signal power to interference power, and therefore SIR will be described as an example here.

A method for calculating SIR in the quality measuring unit 201 will be described. When the known signal returned from the mobile communication terminal 100 is Rn (t) and is calculated based on the time axis, the SIR can be calculated from the following equation (1).

In the above equation (1), n = 1, 2,..., N, N represents the total number of returned known signal symbols applied to SIR measurement, and n is the number of N symbols. It corresponds to any one. In the case of a multicarrier mobile communication system using a plurality of subcarriers such as FDM, OFDM, OFCDM, etc., the SIR is calculated using the above equation (1) for the number of subcarriers. The above equation (1) can also be applied to multicarrier mobile communication systems and other mobile communication systems. Alternatively, the SIR can also be calculated from the following equation (2) based on the frequency axis.

  In the above equation (2), n = 1, 2,..., N, N represents the total number of subcarriers of the returned known signal applied to SIR measurement, and n is the number of N subcarriers. Corresponds to one of them. The above equation (2) is applicable only in a multicarrier mobile communication system.

  In the AMC determination unit 202, the code used when encoding the transmission data in the encoding process 210 based on the SIR measured from the known signal returned from the mobile communication terminal 100 by the quality measurement unit 201 as described above. And a modulation scheme in the transmission processing unit 132 are determined.

  The coding rate R is R = k / j when k information symbols are mapped to j code symbols.

  Specifically, the AMC determination unit 202 stores a management table as shown in FIG. In the management table, the relationship between SIR (SINR), modulation scheme, and coding rate is recorded.

  The AMC determination unit 201 refers to the management table and determines the modulation scheme and coding rate corresponding to the SIR from the measured SIR (SINR) value. FIG. 3 shows an example of the management table. In this management table, for example, when the SIR is measured as “0 dB”, the modulation method is QPSK (quadrature PSK) and the coding rate is “5/6”. To do. When the SIR is “0 dB” as a reference, when the reception quality characteristic deteriorates (ie, when the SIR value decreases), the modulation method remains unchanged (the amount of information transmitted per unit time is changed). In other words, the coding rate includes redundancy that can easily perform error correction in that state. That is, in the management table of FIG. 3, when the SIR is “−3 dB”, the ratio (encoding rate) of the original information amount to the encoded information amount is reduced to “1/3”. On the other hand, on the basis of the case where the SIR is “0 dB”, when the reception quality characteristic becomes better (that is, when the SIR value is improved), a highly efficient modulation method such as 16QAM is used. Increase the amount of information transmitted per unit time. At this time, in the management table of FIG. 3, the higher the SIR value, the higher the coding rate.

  With the configuration shown in FIG. 2, the base station 120 transmits a predetermined known signal, and when the mobile communication terminal 100 receives the known signal, it returns it to the base station 120. The base station 120 can perform closed-loop adaptive modulation and coding control by measuring the reception quality characteristics (for example, SIR and SINR) of the mobile communication terminal 100 based on the returned known signal. Accordingly, it is possible to provide a mobile communication system that performs closed-loop adaptive modulation and coding control that maintains an optimal communication state according to the state of a wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal 100. Is possible. In addition, when applied to a multicarrier mobile communication system including a plurality of subcarriers such as OFDM, particularly when performing adaptive modulation and coding control for each subcarrier, the mobile communication terminal 100 uses each subcarrier. In addition, since it is not necessary to measure SIR or SINR, or to perform closed-loop adaptive modulation and encoding control, the processing load of the mobile communication terminal 100 can be reduced and the size and weight can be reduced.

(Second example)
As a second example of closed-loop adaptive control, quality characteristics (SIR, SINR, etc.) are measured from a known signal returned from mobile communication terminal 100, and base station 120, mobile communication terminal 100, The case where the transmission power used for communication between the two is controlled will be described. A configuration example of the base station 120 in this case is shown in FIG. In FIG. 4, the same parts as those in FIGS. 1 and 2 are given the same reference numerals, and only different parts will be described. That is, in FIG. 4, the measurement unit 127 and the adaptive control processing unit 128 of FIG. 1 are the quality measurement unit 201 and the transmission power control unit 203, respectively.

  The closed loop information extraction unit 126 extracts a known signal transmitted from the mobile communication terminal 100 from the demodulation result for the baseband digital signal obtained by the reception processing unit 123 and outputs it to the quality measurement unit 201.

  The quality measurement unit 201 measures quality characteristics such as signal-to-interference power ratio (SIR), signal-to-interference, and noise power ratio (SINR) of the input known signal, and outputs the measurement result to the transmission power control unit 203. The transmission power control unit 203 determines a gain parameter for the transmission signal based on the input measurement value of the quality characteristic, and outputs it to the transmission processing unit 132 and the wireless processing unit 122. The transmission processing unit 132 and the wireless processing unit 122 control transmission power according to the input gain parameter.

  The quality measuring unit 201 calculates SIR as the reception quality characteristic at the mobile communication terminal 100 from the known signal returned from the mobile communication terminal 100 in the same manner as in the first example.

  The transmission power control unit 203 determines and manages a reference SIR for each user in advance. This reference SIR is determined by the service content provided to the user. Specifically, a relatively large standard SIR is determined for services that require high reliability such as voice communication, and a relatively small standard SIR is determined for services that do not require high reliability such as Web data download. To do. Also, a relatively large reference SIR may be determined for high-speed communication, and a relatively small reference SIR may be determined for low-speed communication. Further, the reference SIR may be dynamically changed according to the communication state at that time.

  The transmission power control unit 203 compares the measured SIR (SINR) with the reference SIR, and transmits transmission data to the mobile communication terminal 100 when the measured SIR <reference SIR, that is, when the measured SIR is smaller than the reference SIR. The gain parameter is determined so that the transmission power at that time is increased by a predetermined value (for example, 1 dB) from the current state. Conversely, when measured SIR> = reference SIR, that is, when the measured SIR is greater than or equal to the reference SIR, the transmission power when transmitting transmission data to mobile communication terminal 100 is reduced by a predetermined value (for example, 1 dB) from the current state. Determine the gain parameter.

  With the configuration shown in FIG. 4, the base station 120 transmits a predetermined known signal, and when the mobile communication terminal 100 receives the known signal, it returns it to the base station 120. The base station 120 can perform closed-loop transmission power control by measuring the reception quality characteristics (for example, SIR and SINR) of the mobile communication terminal 100 based on the returned known signal. Accordingly, it is possible to provide a mobile communication system that performs closed-loop control control that maintains an optimal communication state according to the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal. In addition, when applied to a multicarrier mobile communication system including a plurality of subcarriers such as OFDM, particularly when performing transmission power control for each subcarrier, the mobile communication terminal 100 performs SIR or Since there is no need to perform SINR measurement or transmission power control, the processing load of the mobile communication terminal 100 can be reduced and the size and weight can be reduced.

(Third example)
As a third example of the closed-loop adaptive control, for example, when the base station 120 performs transmission / reception with the mobile communication terminal 100 using a plurality of antennas such as an adaptive array antenna, the base station 120 receives more information from the mobile communication terminal 100. The transmission weight for each antenna for controlling the directivity based on the measurement result by measuring the channel characteristic from the returned known signal (for example, using a plurality of subcarrier signals (multicarrier signals)) The case of determining will be described. A configuration example of the base station 120 in this case is shown in FIG. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals, and only different parts will be described. That is, in FIG. 2, the wireless processing unit 122, the measurement unit 127, and the adaptive control processing unit 128 of FIG. 1 are a wireless processing unit 204, a channel characteristic calculation unit 205, and a weight calculation unit 206, respectively. In addition, the base station 120 includes at least two antennas 401-1 to 401-n (for example, n in FIG. 5), and the radio processing unit 204 includes antennas 401-1 to 401-n. The received radio signal is input, and the transmission signal output from the transmission processing unit 132 is transmitted using each of the antennas 401-1 to 401-n. At this time, the wireless processing unit 204 controls the directivity of the antennas 401-1 to 401-n according to the transmission weight calculated by the weight calculation unit 206.

  The closed loop information extraction unit 126 extracts a known signal transmitted from the mobile communication terminal 100 from the demodulation result for the baseband digital signal obtained by the reception processing unit 123, and outputs it to the channel characteristic calculation unit 205. .

  The channel characteristic calculation unit 205 calculates the channel characteristic between the mobile communication terminal 100 and the base station 120 from the input known signal (for example, the amplitude characteristic appearing in the amplitude of the known signal and the phase of the known signal). The phase characteristics that appear) are obtained and output to the weight calculation unit 206.

  The weight calculation unit 206 determines the transmission weight for each of the antennas 401-1 to 401-n using the input channel characteristics and outputs it to the radio processing unit 402. The radio processing unit 402 multiplies the transmission signals transmitted from the antennas 401-1 to 401-n by the transmission weight according to the input transmission weights, and determines the directivity of the antennas 401-1 to 401-n and the antenna 401. Controls the channel characteristics between -1 to 401-n and the antenna 101 of the mobile communication terminal.

That is, the weight calculation unit 206 acquires the channel characteristic Hn (t) for each of the antennas 401-1 to 401-n. Here, n is a subscript corresponding to each of the antennas 401-1 to 401-n. For example, by transmitting known signals that are orthogonal to each antenna, the channel characteristics can be obtained for each antenna. The transmission weight is a complex conjugate of the channel characteristics (for example, the amplitude or phase corresponding to the time t of the known signal) acquired for each of the antennas 401-1 to 401-n. Specifically, the transmission weight for the antenna 401-1 is a complex conjugate H1 ^* (t) of the channel characteristic H1 (t), which is the amplitude or phase corresponding to the time t of the known signal received by the antenna 401-1. The transmission weight for the transmission antenna 401-2 is the complex conjugate H2 ^* (t) of the channel characteristic H2 (t), which is the amplitude or phase corresponding to the time t of the known signal received by the antenna 401-2. This weight calculation method is the most basic.

  With the configuration shown in FIG. 5, the base station 120 transmits a predetermined known signal (for example, a multicarrier signal (broadband radio signal) including a plurality of subcarrier signals), and the mobile communication terminal 100 receives the wideband radio signal. Then, a known signal is extracted from each subcarrier signal and returned to the base station 120. The base station 120 measures the channel characteristics of the mobile communication terminal 100 (for example, the amplitude or phase of the known signal received by the base station 120) based on the returned known signal, thereby performing closed loop antenna weight control. Can be done. As a result, it is possible to provide a mobile communication system that performs closed-loop antenna weight control that maintains an optimal communication state according to the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal 100. Become.

(Fourth example)
As a fourth example of closed-loop adaptive control, closed-loop adaptive control in a wireless communication system (for example, VSF-OFCDM) in which the spreading factor can be changed by combining features of a multicarrier scheme and CDMA (code division multiple access) The base station 120 measures the channel characteristics (for example, the amplitude and phase of the known signal at time t) H (t) from the known signal returned from the mobile communication terminal 100, and based on this measurement result A case where the signal spreading factor SF (spreading factor) is determined will be described. A configuration example of the base station 120 in this case is shown in FIG. In FIG. 6, the same parts as those in FIG. 1 are denoted by the same reference numerals and only different parts will be described. That is, in FIG. 6, the measurement unit 127 and the adaptive control processing unit 128 in FIG. 1 serve as a channel characteristic calculation unit 205 and a spreading factor determination unit 209, respectively. Further, a despreading processing unit 207 and a diffusion processing unit 210 are newly added.

  A baseband digital signal is output from radio processing section 122 to despreading processing section 207. The despreading processing unit 207 performs a despreading process that multiplies the input baseband digital signal by a synchronization process or a spread code replica, and outputs the result to the reception processing unit 123. Similarly to the case of FIG. 1, the reception processing unit 123 performs predetermined reception processing such as demodulation processing and outputs the demodulation result to the decoding processing unit 124 and also to the closed loop information extraction unit 126.

  The closed loop information extraction unit 126 extracts a known signal returned from the mobile communication terminal 100 from the signal output from the reception processing unit 123 and outputs it to the channel characteristic calculation unit 205.

  The channel characteristic calculation unit 205 measures the amplitude and phase of the known signal at the time t as the channel characteristic from the known signal returned from the mobile communication terminal 100, as in the third example. .

  The spreading factor determining unit 209 determines a spreading factor, that is, a spreading gain, based on the channel characteristic calculated by the channel characteristic calculating unit 205, and outputs it to the spreading processing unit 210. Spreading processing section 210 performs spreading processing on the encoded data and the known signal using the spreading code corresponding to the input spreading gain, and outputs the result to transmission processing section 132.

  The spreading factor determining unit 209 observes a change in the amplitude characteristic with time from the communication path characteristic H (t). As a result, a diffusion rate in a range not exceeding the change period is selected. Also, in the case of a multicarrier mobile communication system, spreading factor determination section 209 has amplitude characteristics of each subcarrier output from communication path characteristic calculation section 205 as channel characteristics H (t) (extracted from each subcarrier) Observe the amplitude of the known signal over time). As a result, a spreading factor in a range in which a large change in amplitude characteristics is not observed on the frequency axis is selected.

  With the configuration shown in FIG. 6, when the base station 120 transmits a predetermined known signal and the mobile communication terminal 100 receives the known signal, it returns it to the known station 120. The base station 120 measures the channel characteristics (for example, the amplitude or phase of the known signal received by the base station 120) of the mobile communication terminal 100 based on the returned known signal, thereby performing closed loop spreading gain control. Can be done. As a result, it is possible to provide a mobile communication system that performs closed-loop spreading gain control that maintains an optimal communication state in accordance with the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal 100. Become.

  (2) Next, the known signal extraction unit and the closed loop control unit of the mobile communication terminal will be described. Here, in a mobile communication system called a multi-carrier mobile communication system having a frequency spectrum shown in FIG. 7 and performing communication using a plurality of carrier waves orthogonal to each other, a frame of the format shown in FIG. A case where data is transmitted / received between the station 120 and the mobile communication terminal 100 will be described. As shown in FIG. 7, the multicarrier mobile communication system according to the present embodiment is, for example, an OFDM multicarrier mobile communication system, and uses N subcarrier signals (carrier waves) in total, and sets the frequency between subcarriers. Some overlap. For example, it is assumed that the known signal shown in FIG. 8 is transmitted by N subcarriers as shown in FIG. The known signal transmitted by the base station is determined depending on the system, and is, for example, a binary digital signal of “1”. In a mobile communication terminal that receives the signal, N is used from the viewpoint of ensuring the reliability of the received signal. Treated as a digital signal of value. For example, when N is assumed to be “8”, the received known signal is, for example, symbol data “1E08180D. Shall be transmitted respectively. One octet of data of 2 octets of known signal allocated to one subcarrier is transmitted in the in-phase component (in-phase channel) of the subcarrier, and the other 1 octet of data is transmitted in the subcarrier. It is assumed that transmission is performed using the orthogonal component (orthogonal channel) of the carrier. Further, according to the frame configuration shown in FIG. 8, the known signal is transmitted from the base station 120 every time interval Tp, that is, periodically.

  (2-1) FIG. 9 is a diagram for explaining a first operation of the known signal extraction unit 106 and the closed loop control unit 107 of the mobile communication terminal 100.

  The known signal extraction unit 106 extracts a known signal separated into an in-phase component and a quadrature component from each of the N subcarrier signals, and stores it in a predetermined storage area of the known signal extraction unit 106 as shown in FIG. Store. As a result, (2 × N) × 8-bit known signal data transmitted from the base station 120 through N subcarriers is temporarily stored in the storage area.

  In FIG. 9, the known signal is represented by a digital signal in units of 8 bits. However, the signal is not limited to this and may be in units of any number of bits.

  Subsequently, the closed-loop control unit 107 encodes the data of the known signals stored in the storage area in accordance with the stored order (in order from the first 8-bit data) based on a predetermined timing. 109 or the transmission processing unit 110.

  The transmission processing unit 110 performs predetermined processing such as modulation processing on the encoded data to be transmitted to the base station 120 (output from the encoding processing unit 109) and the known signal output from the base signal extraction unit 106. A transmission process is performed, and the result is output to the radio processing unit 102. From the radio processing unit 102, a known signal is returned to the base station 120 by N subcarriers.

  In this manner, the mobile communication terminal 100 can return the known signal transmitted from the base station 120 to the base station 120 by performing the above-described operation. This has an effect of enabling the base station 120 to perform the measurement of the adaptive control parameter that is conventionally performed in the mobile communication terminal 100. This makes it possible to provide a mobile communication system that performs closed-loop adaptive control that maintains an optimal communication state according to the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal 100. .

  (2-2) Next, other operations of the known signal extraction unit 106 and the closed loop control unit 107 of the mobile communication terminal 100 will be described. FIG. 10 is a diagram for explaining a second operation of the known signal extraction unit 106 and the closed loop control unit 107 of the mobile communication terminal 100.

  Similar to the first operation, the known signal extraction unit 106 separates the known signal separated into the in-phase component and the quadrature component from each of the signals corresponding to each of the N subcarriers output from the reception processing unit 103. 9 is extracted and stored in a predetermined storage area of the known signal extraction unit 106 as shown in FIG. As a result, (2 × N) × 8-bit known signal data transmitted from the base station 120 through N subcarriers (subcarriers 1 to N) is temporarily stored in the storage area.

  In the second operation, all data of the known signals stored in the storage area are not returned to the base station 120, but only a part of the data is returned. The process of reducing the data amount of the known signal to be returned by selecting the data of the known signal to be returned to the base station 120 in the closed loop control unit 107 is referred to as a reduction process here. Usually, there is a correlation between the quality characteristics and channel characteristics of a plurality of adjacent subcarriers. By utilizing this correlation, even when only a part of the data of the known signal is returned, the closed loop adaptive control can be performed without impairing the reliability.

  In FIG. 10, the closed loop control unit 107 stores only the data of known signals extracted from the subcarriers of odd numbers 1, 3, 5,... N among the subcarriers 1 to N based on a predetermined timing. The data is read out in the order stored in the area and output to the encoding processing unit 109 or the transmission processing unit 110. In this case, the data amount of the known signal to be returned is ½.

  In the above reduction processing, the subcarriers that do not return the known signal or the data that is not returned (reduced) among the data of the known signal may be variable at a predetermined timing, that is, every known signal period Tp. Is possible.

  Further, how much the data amount of the known signal is reduced according to the reception environment of the mobile communication terminal 100 (for example, not to return the data of the known signal in the subcarriers out of the N subcarriers in total) The number of subcarriers to be performed) can be determined each time. This will be described with reference to FIG.

  Some of the signals received by the mobile communication terminal 100 directly receive the signal transmitted from the base station 120 (direct wave), while others are reflected by a nearby building or a distant building (delayed wave) There is also. The reception environment in the mobile communication terminal 100 is represented by the degree of dispersion of multipath generated when the radio signal transmitted from the base station 120 arrives at the mobile communication terminal 100 through a plurality of paths (multipath). be able to. That is, when multipath dispersion (that is, dispersion of delay wave reception (arrival) timing) is large, the correlation between adjacent subcarriers is small, and when the dispersion is small, the correlation between adjacent subcarriers is small. The relationship grows.

  FIG. 11 shows a distribution of delay wave arrival timing, that is, multipath arrival timing (Path Timing). This can usually be acquired at the time of synchronization processing performed by the reception processing unit 103 of the mobile communication terminal 100. Here, σ represents the magnitude of multipath dispersion, and Dth represents an arbitrarily set threshold.

  As shown in FIG. 11A, the closed-loop control unit 107 determines that the correlation between adjacent subcarriers is small when the relationship of σ> Dth is established, and does not perform reduction. As shown in b), when the relationship of σ <= Dth is established, it is determined that the correlation between adjacent subcarriers is large, and control is performed to perform reduction. It should be noted that a plurality of arbitrarily set threshold values Dth are set, and the amount of data that is not returned according to the number of threshold values (hereinafter, in the meaning of the number of subcarriers that do not return data of known signals among N subcarriers in total) , Called the number of reductions).

  Here, a specific calculation method of σ and the value of the threshold value Dth will be described.

11 (a) and 11 (b), it is assumed that the reception timing of each delayed wave of the reception signal of the mobile communication terminal 100 is Tn and the reception power is Pn. Further, N is the number of delayed waves that arrive (number of multipaths). In the example of FIGS. 11A and 11B, N = 5. In this case, σ can be obtained from the following equation (3).

  The threshold value Dth is, for example, an arbitrary integer equal to or less than the number of subcarriers, and is determined depending on the system.

When the subcarrier frequency interval of the system is Δf, Dth is compared with 1 / (Δf × σ). The comparison method when three types of Dth are defined is:
When 1 / (Δf × σ) <Dth1, there is no reduction. When Dth1 <= 1 / (Δf × σ) <Dth2, the number of reductions = Dth1.
When Dth2 <= 1 / (Δf × σ) <Dth3, the number of reductions = Dth2
When Dth3 <= 1 / (Δf × σ), the number of reductions = Dth3
And Or
If 1 / (Δf × σ) <Dth1, there is no reduction. If Dth1 <= 1 / (Δf × σ) <Dth2, the number of reductions = Dth1 / 2.
When Dth2 <= 1 / (Δf × σ) <Dth3, the number of reductions = Dth2 / 2
When Dth3 <= 1 / (Δf × σ), the number of reductions = Dth3 / 2
The number of reductions may be determined as follows. The former is called the first comparison method, and the latter is called the second comparison method. Note that 1 / (Δf × σ) is a value serving as a reference for the number of subcarriers having a correlation with quality characteristics and channel characteristics.

  Assuming that Δf = 100 kHz, Dth1 = 5, Dth2 = 10, Dth3 = 20 and σ = 1 μs, 1 / (Δf × σ) = 10. Therefore, according to the first comparison method, the reduction number is determined to be “10”, and according to the second comparison method, the reduction number is determined to be “5”. Dth depends on the number of subcarriers in the system, but about several tens is sufficient.

  In the second operation described with reference to FIGS. 10 and 11, the reduction is performed based on the frequency axis, but the same reduction can be easily applied to the time axis direction. This is suitable for a mobile communication system in which a known signal is continuously transmitted from a base station as shown in FIG. 12, which is different from the frame format shown in FIG. When the received wireless signal is received by the mobile communication terminal, the second operation is applied in the case where the mobile communication terminal is moved or the peripheral object is moved, and is accompanied by periodic power fluctuations. Can do.

  Here, a case will be described in which mobile communication terminal 100 and base station 120 are mobile communication terminals and base stations in such a mobile communication system. FIG. 13 shows power fluctuations of radio signals received by the mobile communication terminal 100. The fluctuation of the received power as shown in FIG. 13 can be acquired by observing the power change of the received signal during the synchronization process in the reception processing unit 103. Here, t represents a power fluctuation period, and Fth represents a threshold value that is arbitrarily set.

  As shown in FIG. 13A, the closed-loop control unit 107 determines that the time variation period is small when the relationship of t <Fth is established, and does not perform reduction in the time domain. That is, the closed loop control unit 107 returns all received known signals. As shown in FIG. 13B, when the relationship of t> = Fth is established, it is determined that the time variation period is large, and the time domain reduction is performed on a part of the known signal that is temporally continuous. Control to do. That is, the closed loop control unit 17 sets a time during which the received known signal is not returned. It is also possible to set a plurality of arbitrarily set threshold values Fth and determine the reduction time interval according to the number of threshold values.

The threshold value Fth will be described. Fth is an arbitrary integer and is determined depending on the system. If the symbol period of the system (time interval for transmitting a known signal) is Tsym and the fluctuation period of the received power measured by the mobile communication terminal 100 is Tf, Fth is compared with Tf / Tsym. The specific comparison method when three types of Fth are defined is:
If Tf / Tsym <Fth1, no reduction. If Fth1 <= Tf / Tsym <Fth2, the number of reductions = Fth1.
When Fth2 <= Tf / Tsym <Fth3, the number of reductions = Fth2
When Fth3 <= Tf / Tsym, the number of reductions = Fth3
And Or
If Tf / Tsym <Fth1, no reduction is performed. If Fth1 <= Tf / Tsym <Fth2, the number of reductions = Fth1 / 2.
When Fth2 <= Tf / Tsym <Fth3, the number of reductions = Fth2 / 2
When Fth3 <= Tf / Tsym, the number of reductions = Fth3 / 2
The number of reductions may be determined as follows. The former is called the third comparison method, and the latter is called the fourth comparison method. Tf / Tsym is a reference value for the number of symbols in the time axis direction having a correlation with the quality characteristic and the channel characteristic.

  Assuming that Tsym = 10 μs, Fth1 = 5, Fth2 = 10, Fth3 = 20, and Tf = 5 ms, Tf / Tsym = 500. Therefore, according to the third comparison method, the reduction number is determined to be “20”, and according to the fourth comparison method, the reduction number is determined to be “10”. Thus, Tf / Tsym is expected to be a very large value. However, considering a sudden change in channel characteristics, Fth should be about several tens.

  When the mobile communication terminal 100 performs the second operation described above, the known signal transmitted from the base station 120 can be returned to the base station 120. This has the effect of enabling the base station 120 to perform the measurement of the adaptive control parameter that has been conventionally performed in the mobile communication terminal. Furthermore, even when the data amount of the known signal returned by the mobile communication terminal 100 is reduced, the reliability of the closed loop adaptive control is maintained. As a result, the optimal communication state is maintained according to the state of the wireless communication path without increasing the circuit size and power consumption of the mobile communication terminal 100 and suppressing the amount of data and the number of signals transmitted by the mobile communication terminal 100. It is possible to provide a mobile communication system that performs closed-loop adaptive control.

  (2-3) Next, the third operation of the known signal extraction unit 106 and the closed loop control unit 107 of the mobile communication terminal 100 will be described.

  Similar to the first to second operations, the known signal extraction unit 106 extracts the known signal separated into the in-phase component and the quadrature component by the reception processing unit 103, and as shown in FIG. Stored in a predetermined storage area. As a result, (2 × N) × 8-bit known signal data transmitted from the base station 120 through N subcarriers (subcarriers 1 to N) is temporarily stored in the storage area.

  In the third operation, the closed-loop control unit 107 extracts the known signal data extracted for each subcarrier according to the order in which the known signal data stored in the storage area is stored based on a predetermined timing. Extract the differences between them. Specifically, the in-phase component and the quadrature component of the subcarrier 1 are left as they are, and the difference between the in-phase component of the subcarrier 1 and the in-phase component of the subcarrier 2 is subsequently determined. The difference between the quadrature component and the difference between the in-phase component of the subcarrier 2 and the in-phase component of the subcarrier 3 are continued, and the coding processing unit is a digital signal of K bits (K is an arbitrary integer and K <N). 109 or the transmission processing unit 110.

  This is an application of the fact that the difference in quality characteristics and communication path characteristics is usually small in adjacent subcarriers. That is, even when the number of bits to be returned is reduced by returning the difference, it means that the closed loop adaptive control can be performed without greatly impairing the reliability.

  When the mobile communication terminal 100 performs the third operation described above, the known signal transmitted from the base station 120 can be returned to the base station 120. This has the effect of making it possible for the base station to perform the measurement of adaptive control parameters, which has been conventionally performed in mobile communication terminals. Furthermore, even when the data amount of the known signal returned by the mobile communication terminal 100 is reduced, the reliability of the closed loop adaptive control is maintained. As a result, the closed loop adaptation that maintains the optimum communication state according to the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal 100 and suppressing the number of signals transmitted by the mobile communication terminal 100 It is possible to provide a mobile communication system that performs control.

  (2-4) Next, the fourth operation of the known signal extraction unit 106 and the closed loop control unit 107 of the mobile communication terminal 100 will be described.

  Similar to the first to third operations, the known signal extraction unit 106 extracts the known signal separated into the in-phase component and the quadrature component in the reception processing unit 103, and as shown in FIG. Stored in a predetermined storage area. As a result, (2 × N) × 8-bit known signal data transmitted from the base station 120 through N subcarriers (subcarriers 1 to N) is temporarily stored in the storage area.

  As described above, the known signal extraction unit 106 stores the data of the known signal extracted from the radio signal received this time, but in the fourth operation, the data of the known signal extracted from the previously received radio signal is also Keep it in the storage area. In the fourth operation, the closed-loop control unit 107 performs, for each subcarrier, according to the order in which the data (symbols) of the known signals stored in the storage area are stored based on a predetermined timing. A difference from the previously extracted symbol of the known signal is obtained and output to the encoding processing unit 109 or the transmission processing unit 110 as a K-bit (K is an arbitrary integer and K <N) digital signal.

  This is an application of small variations in quality characteristics and channel characteristics in the transmission cycle Tp of symbols of generally known signals. In other words, even when the number of bits to be returned is reduced by returning the difference between the previously received known signal symbol and the currently received symbol symbol, the closed loop adaptive control can be performed without impairing reliability. Is possible.

  When the mobile communication terminal 100 performs the above-described fourth operation, the known signal transmitted from the base station 120 can be returned to the base station 120. This has the effect of making it possible for the base station to perform the measurement of adaptive control parameters, which has been conventionally performed in mobile communication terminals. Furthermore, even when the number of signals transmitted by the mobile communication terminal 100 is reduced, there is an effect of maintaining the reliability of the closed loop adaptive control. As a result, the closed loop adaptation that maintains the optimum communication state according to the state of the wireless communication path without increasing the circuit scale and power consumption of the mobile communication terminal 100 and suppressing the number of signals transmitted by the mobile communication terminal 100 It is possible to provide a mobile communication system that performs control.

  The above description is applicable to multi-carrier communication systems such as OFDM and OFCDM unless otherwise specified.

  In the above description, the base station 120 transmits a signal (known signal) that already knows the bit string, and the mobile communication terminal 100 receives and returns the signal. is not limited to this case, between the base station 120 and the mobile communication terminal 100, (set in advance at the time or system construction) previously negotiated leave whether to send a signal in advance what kind of bit string, both The mobile communication terminal 100 may transmit a bit string defined between the mobile stations (at least a bit string already known by the base station 120). Even in this case, all the operations at the base station 120 are applicable.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components 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 showed the basic structural example of the mobile communication system concerning embodiment of this invention. The figure which showed the structural example of the base station concerning the 1st example of the closed loop adaptive control in a base station. The figure which showed an example of the management table for determining a modulation system and a coding rate based on SIR measured from the known signal. The figure which showed the structural example of the base station concerning the 2nd example of the closed loop adaptive control in a base station. The figure which showed the structural example of the base station concerning the 3rd example of the closed loop adaptive control in a base station. The figure which showed the structural example of the base station concerning the 4th example of the closed loop adaptive control in a base station. The figure which showed the frequency spectrum of each subcarrier in an OFDM multicarrier mobile communication system. The figure which showed an example of the transmission timing of the known signal transmitted from a base station. The figure for demonstrating the 1st operation | movement of a mobile communication terminal. The figure for demonstrating the 2nd operation | movement of a mobile communication terminal. The figure for demonstrating the reception timing of the delay wave in a mobile communication terminal. The figure which showed the other example of the transmission timing of the known signal transmitted from a base station. The figure for demonstrating the 2nd operation | movement of a mobile communication terminal, and the figure for demonstrating the reduction method of the known signal returned based on the period of the electric power fluctuation | variation of the radio signal which a mobile communication terminal receives. The figure for demonstrating the 3rd operation | movement of a mobile communication terminal. The figure for demonstrating the 4th operation | movement of a mobile communication terminal.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Mobile communication terminal, 101 ... Antenna, 102 ... Radio processing part, 103 ... Reception processing part, 104 ... Decoding processing part, 105 ... Reception buffer, 106 ... Known signal extraction part, 107 ... Closed loop control part, 108 ... Transmission buffer 109: Encoding processing unit, 110: Transmission processing unit, 111 ... Controller, 120 ... Base station apparatus, 121 ... Antenna, 122 ... Radio processing unit, 123 ... Reception processing unit, 124 ... Decoding processing unit, 125 ... Reception buffer , 126 ..., closed loop information extraction unit, 127 ... measurement unit, 128 ... adaptive control processing unit, 129 ... transmission buffer, 130 ... encoding processing unit, 131 ... base signal insertion unit, 132 ... transmission processing unit, 133 ... controller.

Claims (11)

A wireless communication system that performs communication between a base station and a terminal using a multicarrier signal including a plurality of subcarrier signals,
The terminal
First receiving means for receiving the multicarrier signal including a known signal transmitted from the base station;
Before extracting the multicarrier signal received by the first receiving means, first extracting means for extracting the known signal separated from the multicarrier signal into an in-phase component and a quadrature component;
In order to measure the adaptive control parameters including the amplitude and phase characteristics of the known signal extracted by the first extracting means at the base station, all or one of the known signals extracted by the first extracting means. Transmitting means for transmitting the multicarrier signal including a section;
Including
The base station
Second receiving means for receiving the multicarrier signal transmitted by the transmitting means;
Second extracting means for extracting the known signal from the multicarrier signal before decoding the multicarrier signal received by the second receiving means;
Measuring means for measuring the adaptive control parameter from the known signal extracted by the second extracting means;
Based on the adaptive control parameter measured by the measuring means, at least one of a modulation scheme used for communication with the terminal, a coding rate, and a parameter value for adjusting transmission power, Means to determine ,
Wireless communication system comprising a. The base station
A plurality of antennas for transmitting and receiving the multicarrier signal;
Means for determining a transmission weight for each of the plurality of antennas based on the adaptive control parameter measured by the measuring means ;
The wireless communication system according to claim 1 , further comprising: The wireless communication system according to claim 1 , wherein the known signal is a pilot signal known between the terminal and the base station, which is determined uniquely for the wireless communication system. A mobile communication terminal apparatus that communicates with a base station using a multicarrier signal composed of a plurality of subcarrier signals,
Receiving means for receiving the multicarrier signal including a known signal transmitted from the base station;
Extraction means for extracting the known signal separated into an in-phase component and a quadrature component from the multi-carrier signal before decoding the multi-carrier signal received by the receiving means;
The multi-carrier including all or part of the known signal extracted by the extracting means for measuring, at the base station, an adaptive control parameter including amplitude and phase characteristics of the known signal extracted by the extracting means. Transmitting means for transmitting a signal to the base station;
Comprising
The adaptive control parameter is measured from the known signal extracted from the multicarrier signal before decoding the multicarrier signal by the base station that has received the multicarrier signal transmitted by the transmission means, Based on an adaptive control parameter, at least one of a modulation scheme used for communication between the base station and the mobile communication terminal apparatus, a coding rate, and a parameter value for adjusting transmission power is determined. A mobile communication terminal device. The transmission unit, based on the reception timing of a delay wave of the multi-carrier signal transmitted from the base station, according to claim 4, wherein reducing the data amount of said known signal to be transmitted to the base station Mobile communication terminal device. A mobile communication terminal apparatus that communicates with a base station using a multicarrier signal composed of a plurality of subcarrier signals,
Receiving means for receiving the multicarrier signal including a known signal transmitted from the base station;
Extraction means for extracting the known signal separated into an in-phase component and a quadrature component from the multi-carrier signal before decoding the multi-carrier signal received by the receiving means;
In order to measure the adaptive control parameters including the amplitude and phase characteristics of the known signal extracted by the extracting means at the base station, the extracting means extracts from the multicarrier signal currently received by the receiving means. Transmitting means for transmitting to the base station the multicarrier signal including a difference between the known signal and the known signal extracted from the multicarrier signal previously received by the receiving means by the extracting means;
A mobile communication terminal apparatus comprising: A base station apparatus that communicates with a terminal using a multicarrier signal composed of a plurality of subcarrier signals,
Transmitting means for transmitting the multicarrier signal including a known signal;
Before receiving the multicarrier signal transmitted by the transmission means and decoding the multicarrier signal, the known signal separated into in-phase and quadrature components is extracted from the multicarrier signal and the known In order to measure the adaptive control parameters including the amplitude and phase characteristics of the signal in the base station apparatus, the base station apparatus transmits the multicarrier signal including all or part of the known signal transmitted from the terminal. Receiving means for receiving a multicarrier signal including all or part of the known signal extracted from the multicarrier signal;
Extracting means for extracting the known signal from the multicarrier signal before decoding the multicarrier signal received by the receiving means;
Measuring means for measuring the adaptive control parameter from the known signal extracted by the extracting means;
Based on the adaptive control parameter measured by the measuring means, at least one of a modulation scheme used for communication with the terminal, a coding rate, and a parameter value for adjusting transmission power, Means to determine ,
A base station apparatus comprising: A plurality of antennas for transmitting and receiving the multi-carrier signal;
Means for determining a transmission weight for each of the plurality of antennas based on the adaptive control parameter measured by the measuring means ;
The base station apparatus according to claim 7 , further comprising: A wireless communication method between a base station and a terminal using a multicarrier signal composed of a plurality of subcarrier signals,
A first transmission step in which the base station transmits the multicarrier signal including a known signal;
A first reception step in which the terminal receives the multicarrier signal transmitted in the first transmission step;
A first extraction step of extracting, from the multicarrier signal, the known signal separated into an in-phase component and a quadrature component before the terminal decodes the multicarrier signal received in the first reception step; ,
A second transmission step in which the terminal transmits the multicarrier signal including all or part of the known signal extracted in the first extraction step;
A second receiving step in which the base station receives the multicarrier signal transmitted in the second transmitting step;
A second extraction step in which the base station extracts the known signal from the multicarrier signal before decoding the multicarrier signal received in the second reception step;
A measuring step in which the base station measures an adaptive control parameter including amplitude and phase characteristics of the known signal extracted by the terminal in the first extraction step from the known signal extracted in the second extraction step; ,
Based on the adaptive control parameter measured in the measurement step by the base station , out of parameter values for adjusting the type of modulation scheme used for communication with the terminal, the coding rate, and the transmission power Determining at least one ;
A wireless communication method comprising: The base station comprises a plurality of antennas for transmitting and receiving the multicarrier signal,
The base station determining a transmission weight for each of the plurality of antennas based on the adaptive control parameter measured in the measurement step;
The wireless communication method according to claim 9 , further comprising : The wireless communication method according to claim 9 , wherein the known signal is a known pilot signal between the terminal and the base station.

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