JP2009284534A - Radio communication device, radio communication method, and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the interference with a communication terminal device which performs communication, using an HDR, with another base station device and a communication terminal device which is performing communication, using the HDR, with its station at the same time. <P>SOLUTION: A radio communication device includes a table wherein a plurality of combinations of modulation systems, transmission power adjustment values, and information corresponding to combinations of the modulation systems and transmission power adjustment values are set, a reception means of receiving a signal from a communication partner, and a transmission means of transmitting the information corresponding to reception quality of a received signal to the communication partner on the basis of the table, the information representing a modulation system of a prescribed modulation multi-value number and prescribed transmission power when the reception quality has a prescribed value, a modulation system of a modulation multi-value number smaller than the prescribed modulation multi-value number and the prescribed transmission power when the reception quality is lower than the prescribed value, and a prescribed modulation system and transmission power smaller than the prescribed transmission power when the reception quality is higher than the prescribed value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus, a wireless communication method, and a wireless communication system used in a cellular communication system.

  In a cellular communication system, one base station performs wireless communication simultaneously with a plurality of communication terminals. In this cellular communication system, it is required to increase transmission efficiency.

  HDR (High Data Rate) has been proposed as a technique for improving the transmission efficiency of a downlink from a base station to a communication terminal. HDR is a method of performing a scheduling for allocating communication resources to each communication terminal in a time division manner, and further setting a transmission rate for each communication terminal according to communication quality to increase data transmission efficiency.

  Hereinafter, communication using HDR will be described with reference to FIG. In FIG. 22, the base station 11 is currently communicating with the communication terminals 12 to 14 existing in the cell area 15 covered by the base station 11. The communication terminals 20 to 22 exist within the cell area 15 but communicate with a base station (not shown) other than the base station 11.

  First, the base station 11 transmits a pilot signal to the communication terminals 12 to 14. Using the pilot signal transmitted to the base station 11, the communication terminals 12 to 14 estimate the communication quality by CIR (desired wave-to-interference wave ratio) or the like, and obtain a transmission rate at which communication is possible. Further, the communication terminals 12 to 14 select a communication mode indicating a combination of packet length, error correction, and modulation method based on a communicable transmission rate, and transmit a signal indicating the communication mode to the base station 11. .

  The base station 11 performs scheduling based on the communication mode selected by the communication terminals 12 to 14, sets a transmission rate for each communication terminal, and transmits a signal indicating communication resource allocation to the communication terminals 12 to 14 through the control channel. Inform.

  The base station 11 transmits data via the data channel only to the corresponding communication terminal at the allocated time. For example, when time t1 is allocated to communication terminal 12, base station 11 transmits data only to communication terminal 12 and does not transmit data to communication terminal 13 and communication terminal 14 at time t1. . Moreover, the transmission power when the base station 11 transmits data to the communication terminals 12 to 14 is always constant.

  In the HDR, in parallel with the communication as described above, the base station 11 and the communication terminals 12 to 14 use a frequency band different from the frequency band used for the HDR, and use a normal CDMA (Code Division). Multiple Access) communication.

  However, the communication using the conventional HDR has the following problems. That is, referring to FIG. 22 again, the base station 11 always transmits data to each communication terminal using constant power regardless of the distance between the communication terminals 12 to 14. The power at this time is large so that the reception quality at all communication terminals existing in the cell area 15 is sufficiently good.

  For this reason, among communication terminals performing communication using base stations other than the base station 11 (hereinafter referred to as “other base stations”) using HDR, communication terminals existing in the cell area 15 covered by the base station 11. (Communication terminals 20 to 22 in FIG. 22) may be interfered by a signal transmitted from the base station 11 to any one of the communication terminals 12 to 14. As a result, the reception quality of the communication terminal that has received interference as described above deteriorates. For example, when the time for the base station 11 to transmit data to the communication terminal 12 via the data channel matches the time for the other base station to transmit data to the communication terminal 20 via the data channel. The communication terminal 20 is interfered by a signal transmitted from the base station 11 to the communication terminal 12.

  Further, when the base station 11 performs HDR transmission to a plurality of communication terminals (for example, communication terminals 12 to 14) at the same time (in the future, such HDR transmission may be realized). ), The delay waves of the signals transmitted to the plurality of communication terminals interfere with each other, so that the communication quality of the plurality of communication terminals deteriorates.

  As described above, in the communication using the conventional HDR, a base station that performs communication using HDR communicates with a communication terminal that performs communication using HDR with another base station, or the local station at the same time. There is a problem that interference can be given to a communication terminal performing communication.

  The present invention has been made in view of such a point, and performs communication using an HDR with another base station device, and communication using the HDR with the own station at the same time. It is an object of the present invention to provide a wireless communication device, a wireless communication method, and a wireless communication system that can suppress interference on a communication terminal device.

  The base station apparatus according to the first aspect of the present invention comprises: transmission rate setting means for setting a transmission rate of a transmission signal for the communication terminal apparatus based on actual reception quality of the communication terminal apparatus; A power value setting unit that sets a minimum transmission power value that satisfies a desired quality of a received signal in the communication terminal apparatus for a transmission signal as a transmission power value for the communication terminal apparatus, and a set transmission power value is used. And a transmission unit configured to transmit a transmission signal having a set transmission rate to the communication terminal device.

  According to this configuration, since it becomes possible to transmit with the minimum transmission power that can satisfy the quality at the time of HDR transmission, while maintaining the transmission quality for the desired communication terminal apparatus, it is possible to communicate with other base station apparatuses. It is possible to reduce interference with a communication terminal apparatus that performs HDR communication and a communication terminal apparatus that performs communication with the local station at the same time.

  In the base station apparatus according to the second aspect of the present invention, the power value setting means is a standard that is at least necessary for the characteristics of the received signal in the communication terminal apparatus to satisfy the desired quality with respect to the transmission signal of the set transmission rate. Reference reception quality detection means for detecting reception quality is provided, and the transmission power value is set using the difference between the actual reception quality and the reference reception quality.

  According to this configuration, since it becomes possible to accurately determine the minimum transmission power that can satisfy the quality in the base station apparatus, it is possible to reduce interference with other communication terminal apparatuses while reliably maintaining the desired quality. Is possible.

  In the base station apparatus according to the third aspect of the present invention, the transmission rate setting means sets the transmission rate notified by the communication terminal apparatus as the transmission rate of the transmission signal to the communication terminal apparatus, and the power value setting means The minimum transmission power value notified by the communication terminal apparatus is set as the transmission power value for the communication terminal apparatus.

  According to this configuration, it is possible to calculate transmission power that can reliably satisfy the reception quality in the communication terminal apparatus and notify the base station apparatus, so that more accurate transmission power control can be performed in the base station apparatus. It becomes possible.

  In the base station apparatus according to the fourth aspect of the present invention, the power value setting means notifies the transmission power value and the normal transmission power value that are notified by the communication terminal apparatus to satisfy the set transmission rate at a minimum. The transmission power value for the communication terminal apparatus is set using the difference between the two.

  According to this configuration, since the amount of information to be transmitted to the base station apparatus is reduced, it is possible to use the wireless line effectively.

  In the base station apparatus according to the fifth aspect of the present invention, the power value setting means sets the transmission power value necessary for satisfying the set transmission rate to a minimum only when a high-speed transmission rate is applied. A configuration is adopted in which the transmission power value for the communication terminal apparatus is set.

  According to this configuration, it is only necessary to change the transmission power when a high-speed transmission rate that can significantly reduce the transmission power is applied, so that the processing in the base station is reduced while maintaining the interference reduction effect. .

  The base station apparatus according to the sixth aspect of the present invention employs a configuration in which the transmission means transmits a control channel signal using a substantially constant transmission power value.

  According to this configuration, the transmission rate can be selected according to the control channel signal that is always transmitted with constant power, and therefore the transmission rate can be easily selected.

  In the base station apparatus according to the seventh aspect of the present invention, the power value setting means sets a transmission power value selected from a plurality of predetermined transmission power value candidates as a transmission power value for the communication terminal apparatus. The structure to do is taken.

  In the base station apparatus according to the eighth aspect of the present invention, a plurality of transmission power value candidates are reported to a communication terminal apparatus, and the power value setting means communicates the communication signal from a plurality of transmission power value candidates. A configuration for selecting a transmission power value designated by the terminal device is adopted.

  According to these configurations, it is possible to reduce the amount of transmission power information transmitted from the communication terminal apparatus to the base station apparatus, and thus it is possible to reduce radio channel resources.

  A base station apparatus according to a ninth aspect of the present invention is set with transmission rate setting means for setting a transmission rate of a data channel signal for the communication terminal apparatus based on reception quality of a control channel signal in the communication terminal apparatus. Selecting means for selecting a communication terminal apparatus to be a transmission destination of the data channel signal based on the transmission rate, and a communication terminal apparatus having a good reception quality of the data channel signal among the communication terminal apparatuses selected as the transmission destination Determining means for determining whether transmission of the data channel signal to the data channel is dominant in the data channel, and using the transmission power value set based on the determination result of the determining means, the control channel signal and And a transmission means for transmitting a data channel signal to the communication terminal apparatus selected as the transmission destination.

  According to this configuration, when communication of a data channel signal to a communication terminal apparatus with good communication quality is dominant in the data channel, transmission using more transmission power than necessary is performed by changing the transmission power. Therefore, it is possible to suppress interference with a communication terminal device existing in the cell of the own station or the cell of another station.

  In the base station apparatus according to the tenth aspect of the present invention, the determination means detects the number of communication terminal apparatuses whose reception quality of the control channel signal exceeds a predetermined value among the communication terminal apparatuses selected as transmission destinations. And determining using the number of communication terminal devices exceeding the predetermined value.

  According to this configuration, it is possible to suppress interference with communication terminal apparatuses existing in the cell of the local station and the cell of another station and improve the total downlink throughput. In particular, even when the total number of communication terminal apparatuses to which data channel signals are transmitted is small, a decrease in the total downlink throughput can be reliably suppressed.

  The base station apparatus according to the eleventh aspect of the present invention comprises a calculating means for calculating a ratio of the number of communication terminal apparatuses exceeding a predetermined value to the number of communication terminal apparatuses selected as a transmission destination, A configuration is adopted in which determination is performed using the calculated ratio.

  According to this configuration, it is possible to suppress interference with communication terminal apparatuses existing in the cell of the local station and the cell of another station and improve the total downlink throughput.

  In the base station apparatus according to the twelfth aspect of the present invention, the determination means includes distribution detection means for detecting the distribution of the reception quality of the control channel signal in the communication terminal apparatus selected as the transmission destination, and the detected distribution The structure which performs determination using is taken.

  According to this configuration, it is possible to reliably detect whether transmission of transmission data to a communication terminal apparatus with good communication quality is dominant in the downlink.

  In the base station apparatus according to the thirteenth aspect of the present invention, the transmission means includes a change width setting means for setting a change width of the transmission power based on the distribution detected by the distribution detection means, and the set change width Is used to transmit a control channel signal and a data channel signal to a communication terminal device selected as a transmission destination using the transmission power value set based on the above.

  According to this configuration, it is possible to reduce interference with communication terminals in other cells and improve total throughput at high speed and with high accuracy.

  The base station apparatus according to the fourteenth aspect of the present invention provides an estimation means for estimating a change in throughput of a data channel signal based on a transmission rate corresponding to a communication terminal apparatus selected as a transmission destination of the data channel signal. And a transmission means transmits a control channel signal and a data channel signal to a communication terminal device selected as a transmission destination using a transmission power value set based on the estimated change in throughput.

  According to this configuration, it is possible to realize efficient transmission of transmission data by preventing a decrease in downlink throughput caused by lowering transmission data.

  A communication terminal apparatus according to the fifteenth aspect of the present invention is characterized in that it performs radio communication with any of the base station apparatuses described above.

  According to this configuration, it is possible to provide a communication terminal device that can perform good communication.

  The communication terminal apparatus according to the sixteenth aspect of the present invention provides a transmission rate and a minimum transmission power value or a set transmission rate to the base station apparatus only when a high-speed transmission rate is applied. A configuration is adopted in which the difference between the transmission power value necessary for satisfying the minimum and the normal transmission power value is notified.

  According to this configuration, transmission power information or power margin information only needs to be sent to the base station apparatus when a high transmission rate is requested. Therefore, processing in the communication terminal apparatus is reduced, and reduction in power consumption and size reduction can be realized.

  A communication method according to a seventeenth aspect of the present invention includes a transmission rate setting step of setting a transmission rate of a transmission signal to the communication terminal apparatus based on actual reception quality of the communication terminal apparatus, and transmission of the set transmission rate A power value setting step of setting a minimum transmission power value that satisfies a desired quality as a characteristic of a received signal in the communication terminal apparatus for a signal as a transmission power value for the communication terminal apparatus, and using the set transmission power value And a transmission step of transmitting a transmission signal having a set transmission rate to the communication terminal device.

  According to this method, since it becomes possible to transmit with the minimum transmission power that can satisfy the quality at the time of HDR transmission, while maintaining the transmission quality for the desired communication terminal apparatus, It is possible to reduce interference with a communication terminal apparatus that performs HDR communication and a communication terminal apparatus that performs communication with the local station at the same time.

  Advantageous Effects of Invention According to the present invention, it is possible to suppress interference on a communication terminal device that performs communication using HDR with another base station device, and a communication terminal device that performs communication using HDR with the own station at the same time. be able to.

1 is a block diagram showing a configuration of a base station apparatus provided with a communication apparatus according to a first embodiment of the present invention. 1 is a block diagram showing a configuration of a communication terminal apparatus including a communication apparatus according to a first embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a transmission rate determination method by a request modulation scheme determination unit of a communication terminal apparatus including the communication apparatus according to the first embodiment of the present invention. 1 is a schematic diagram showing a state in which a communication terminal device including a communication device according to a first embodiment of the present invention and a base station device perform communication using HDR. FIG. 3 is a block diagram showing a configuration of a communication terminal apparatus according to a second embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a base station apparatus according to a second embodiment of the present invention. Schematic diagram showing an example of a DRC table used by the communication terminal apparatus according to the second embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of a base station apparatus according to a third embodiment of the present invention. The flowchart which shows operation | movement of the base station apparatus concerning Embodiment 3 of this invention. Block diagram showing the configuration of a base station apparatus according to a fourth embodiment of the present invention. The flowchart which shows operation | movement of the base station apparatus concerning Embodiment 4 of this invention. Block diagram showing a configuration of a communication terminal device according to a fifth embodiment of the present invention. Schematic diagram showing an example of a DRC signal used by the communication terminal apparatus according to the fifth embodiment of the present invention. Block diagram showing the configuration of a base station apparatus according to a fifth embodiment of the present invention. The flowchart which shows operation | movement of the base station apparatus concerning Embodiment 5 of this invention. Block diagram showing the configuration of a base station apparatus according to a sixth embodiment of the present invention. The flowchart which shows operation | movement of the base station apparatus concerning Embodiment 6 of this invention. Schematic diagram conceptually showing an example of the distribution of DRC values reported by the communication terminal apparatus according to the seventh embodiment of the present invention. The flowchart which shows operation | movement of the base station apparatus concerning Embodiment 7 of this invention. The schematic diagram which shows an example of the relationship between the average value and dispersion | distribution of DRC value, and transmission power value in the base station apparatus concerning Embodiment 8 of this invention. The flowchart which shows operation | movement of the base station apparatus concerning Embodiment 8 of this invention. Schematic diagram showing how communication is performed using conventional HDR

  The first essence of the present invention is that the transmission rate of the communication terminal apparatus is set based on the reception quality of the communication terminal apparatus, and the characteristics of the received signal in the communication terminal apparatus regarding the transmission signal of the set transmission rate are desired. Transmission is performed to the communication terminal apparatus using a minimum transmission power value that satisfies the quality.

  The second essence of the present invention is that the transmission of data channel signals to communication terminal devices with good reception quality of data channel signals out of the communication terminal devices selected as data channel signal transmission destinations dominates in the data channels. The transmission power value set based on the result of the determination is used to transmit the control channel signal and the data channel signal to the communication terminal device selected as the transmission destination. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the pilot signal is transmitted from the base station apparatus to the communication terminal apparatus via the control channel, and the data (voice, packet, etc.) is transmitted from the base station apparatus to the communication terminal apparatus via the data channel. Sent to. In addition, signals communicated through the control channel and the data channel are referred to as “control channel signal” and “data channel signal”, respectively.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a base station apparatus provided with a communication apparatus according to Embodiment 1 of the present invention. In FIG. 1, the allocation unit 101 grasps the transmission rate at which each communication terminal apparatus can communicate based on a data rate control (hereinafter referred to as “DRC”) signal detected by a DRC signal detection unit 116 described later. The allocation of communication resources to the communication terminal apparatus is determined, and the buffer 102 is instructed to output downlink transmission data. Here, the DRC signal is a signal indicating a transmission rate at which the communication terminal apparatus can receive with a desired quality. Details of the DRC signal will be described later.

  Also, allocating section 101 instructs downlink coding data encoding method to adaptive coding section 103, instructs modulation modulation section 104 to modulate the downlink transmission data, and transmits to adaptive spreading section 105. Instructs a spreading code to multiply the downlink transmission data.

  Buffer 102 holds downlink transmission data, and outputs downlink transmission data for a predetermined communication terminal apparatus to adaptive encoding section 103 in accordance with an instruction from allocation section 101. Adaptive encoding section 103 encodes the transmission data from buffer 102 in accordance with the instruction from allocation section 101 and outputs the encoded transmission data to adaptive modulation section 104.

  Adaptive modulation section 104 modulates the transmission data encoded by adaptive encoding section 103 in accordance with the instruction from allocation section 101 and outputs the modulated transmission data to adaptive spreading section 105. Adaptive spreading section 105 spreads the transmission data modulated by adaptive modulation section 104 according to the instruction from allocating section 101 and outputs the spread transmission data to multiplexing section 108.

  On the other hand, modulation section 106 modulates the pilot signal and outputs it to spreading section 107. Spreading section 107 spreads the pilot signal modulated by modulating section 106 and outputs the result to multiplexing section 108.

  Multiplexing section 108 generates a transmission signal by time-multiplexing the spread downlink transmission data and the spread pilot signal, and outputs the generated transmission signal to power control section 109. At the start of communication, only the pilot signal is output from multiplexing section 108 to power control section 109.

  The power control unit 109 amplifies the transmission signal generated by the multiplexing unit 108 so that the transmission power value set by the power setting unit 118 described later is obtained, and outputs the amplified transmission signal to the transmission RF unit 110. .

  The transmission RF unit 110 converts the frequency of the transmission signal amplified by the power control unit 109 into a radio frequency and outputs the radio frequency to the duplexer 111. The duplexer 111 transmits the transmission signal converted into the radio frequency by the transmission RF unit 110 to the communication terminal device via the antenna 112. The duplexer 111 outputs a signal (reception signal) transmitted from each communication terminal apparatus and received via the antenna 112 to the reception RF unit 113.

  The reception RF unit 113 converts the frequency of the reception signal from the duplexer 111 into baseband, and outputs the reception signal converted into the baseband to the despreading unit 114. Despreading section 114 despreads the received signal converted into the baseband signal and outputs the result to demodulation section 115. Demodulation section 115 demodulates the reception signal despread by despreading section 114 to generate a demodulated signal, and outputs the generated demodulated signal to DRC signal detection section 116 and power margin information detection section 117.

  The DRC detection unit 116 detects a DRC signal from the demodulated signal generated by the demodulation unit 115 and outputs the detected DRC signal to the allocation unit 101. The power margin information detection unit 117 detects the power margin information from the demodulated signal generated by the demodulation unit 115 and outputs the detected power margin information to the power setting unit 118.

  The power setting unit 118 uses the power margin information from the power margin information detection unit 117 to set the transmission power value of the transmission signal of each communication terminal apparatus, and outputs the set transmission power value to the power control unit 109.

  FIG. 2 is a block diagram illustrating a configuration of a communication terminal apparatus including the communication apparatus according to the first embodiment of the present invention. In FIG. 2, a required modulation scheme determination unit 201 determines a transmission rate at which the communication terminal apparatus can receive with a desired quality based on CIR measured by a CIR measurement unit 214, which will be described later, and determines the determined transmission rate. The data is output to the margin calculation unit 202 and the DRC signal creation unit 203.

  Further, the required modulation scheme determining unit 201 instructs the adaptive despreading unit 210 on a spreading code to multiply the received signal based on the determined transmission rate, and the adaptive demodulating unit 211 demodulates the received signal. And the decoding method of the received signal is instructed to the adaptive decoding unit 212.

  The margin calculating unit 202 calculates a power margin by using the CIR measured by the CIR measuring unit 214 (to be described later) and the transmission rate determined by the required modulation scheme determining unit 201, and obtains information on the calculated power margin, that is, power margin information. The data is output to the combining unit 215.

  The DRC signal creation unit 203 creates a DRC signal indicating the transmission rate calculated by the required modulation scheme determination unit 201 and outputs the DRC signal to the synthesis unit 215.

  The combining unit 215 generates a combined signal by combining the DRC signal from the DRC signal generating unit 203 and the power margin information from the margin calculating unit 202, and outputs the generated combined signal to the modulating unit 204.

  Modulating section 204 modulates the combined signal from combining section 215 and outputs the result to spreading section 205. Spreading section 205 spreads the combined signal modulated by modulating section 204 and outputs the resultant signal to transmission RF section 206. The transmission RF unit 206 frequency-converts the combined signal spread by the spreading unit 205 to a radio frequency and outputs the resultant signal to the duplexer 207.

  The duplexer 207 transmits the combined signal frequency-converted by the transmission RF unit 206 to the base station apparatus via the antenna 208. The duplexer 207 outputs a signal (received signal) transmitted from the base station apparatus and received by the antenna 208 to the reception RF unit 209.

  Reception RF section 209 converts the frequency of the received signal from duplexer 207 to baseband, and outputs the received signal converted to baseband to adaptive despreading section 210 and despreading section 213.

  The adaptive despreading unit 210 despreads the received signal from the reception RF unit 209 in accordance with an instruction from the required modulation scheme determining unit 201 to extract a component other than the pilot signal (component corresponding to data) in the received signal, The extracted component is output to adaptive demodulation section 211. The adaptive demodulation unit 211 demodulates the component extracted by the adaptive despreading unit 210 in accordance with an instruction from the required modulation scheme determination unit 201 to generate a demodulated signal. The adaptive decoding unit 212 extracts received data by decoding the demodulated signal from the adaptive demodulation unit 211 in accordance with an instruction from the required modulation scheme determination unit 201.

  On the other hand, despreading section 213 despreads the received signal from reception RF section 209, extracts the pilot signal component in the received signal, and outputs the extracted pilot signal component to CIR measurement section 214. CIR measurement section 214 measures CIR using the component of the pilot signal from despreading section 213 and outputs the measured CIR to request modulation scheme determination section 201 and margin calculation section 202.

  Next, operations performed between the base station apparatus shown in FIG. 1 and the communication terminal apparatus shown in FIG. 2 will be described.

  First, at the start of communication, a pilot signal is modulated by modulation section 106 in the base station apparatus, spread by spreading section 107, and output to multiplexing section 108. Only the spread pilot signal is output from multiplexing section 108 to power control section 109. The pilot signal from multiplexing section 108 is amplified by power control section 109 so as to have a predetermined transmission power value. The amplified pilot signal is frequency-converted to a radio frequency by the transmission RF unit 110 and transmitted from the antenna 112 to each communication terminal device via the duplexer 111. This pilot signal is transmitted to each communication terminal apparatus via the control channel.

  The pilot signal (control channel signal) transmitted by the base station apparatus is received by the antenna 208 of the communication terminal apparatus. A signal (reception signal) received by the antenna 208 is output to the reception RF unit 209 via the duplexer 207. The reception signal from the duplexer 207 is frequency-converted to baseband by the reception RF unit 209 and despread by the despreading unit 213. Thereby, despreading section 213 extracts a pilot signal from the received signal. The extracted pilot signal is output to CIR measurement section 214.

  The CIR measurement unit 214 measures CIR based on the pilot signal output from the despreading unit 213. The measured CIR is sent to the required modulation method determination unit 201 and the margin calculation unit 202.

  Based on the CIR measured by the CIR measuring unit 214, the required modulation scheme determining unit 201 determines a transmission rate that can be received by the communication terminal apparatus with desired quality. A method of determining the transmission rate by the required modulation method determination unit 201 will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating a transmission rate determination method by the request modulation scheme determination unit 201 of the communication terminal apparatus including the communication apparatus according to the first embodiment of the present invention.

  Based on the CIR (reception quality) measured by the CIR measurement unit 214, the required modulation method determination unit 201 satisfies the desired quality of the received signal (acknowledgment rate characteristic) of the communication terminal apparatus, and transmits data. The transmission rate required for the base station apparatus is determined so that the efficiency is the best.

Specifically, for example, when the CIR measured by the CIR measurement unit 214 is a value (reception CIR 301) as shown in FIG. In this case, a transmission rate that satisfies the apologization rate is 10 ⁻³ ) is any one of a transmission rate corresponding to QPSK, a transmission rate corresponding to 16QAM, and a transmission rate corresponding to 64QAM. Among such transmission rates, the transmission rate that provides the best data transmission efficiency is a transmission rate corresponding to 64QAM. As a result, when the CIR as shown in FIG. 3 is measured, a transmission rate corresponding to 64QAM is determined as a transmission rate required for the base station apparatus.

  The transmission rate determined by the required modulation scheme determination unit 201 as described above is output to the margin calculation unit 202 and the DRC signal creation unit 203. After the transmission rate is determined, the requested modulation scheme determining unit 201 instructs the adaptive despreading unit 210, the adaptive demodulation unit 211, and the adaptive decoding unit 212 to each specify a spreading code to be multiplied with the received signal, A signal instructing the demodulation method of the received signal and a signal instructing the decoding method of the received signal are output.

  The margin calculating unit 202 calculates a power margin using the CIR measured by the CIR measuring unit 214 and the transmission rate determined by the required modulation scheme determining unit 201. That is, the margin calculation unit 202 first applies the transmission rate determined by the required modulation scheme determination unit 201 and receives the reception quality (hereinafter referred to as “first reception quality”) when transmitted from the base station at the requested transmission rate. And the difference between the minimum received quality (hereinafter referred to as “second received quality”) required for the characteristics of the received signal to satisfy the desired quality in this case. Thereafter, a power margin is calculated as a power value corresponding to the calculated difference. This power margin means a transmission power value (normally transmitted transmission power) in the base station apparatus necessary for the communication terminal apparatus to obtain the first reception quality and a communication terminal apparatus for obtaining the second reception quality. This corresponds to the difference from the required transmission power value in the base station apparatus.

Specifically, referring to FIG. 3, first, according to a curve representing the CIR vs. BER characteristic of the transmission rate (transmission rate corresponding to 64QAM) determined by the required modulation scheme determination unit 201, the characteristics of the received signal are desired. The second reception quality (CIR 302) that is the minimum required to satisfy the quality (BER = 10 ⁻³ ) is calculated. Furthermore, after the difference between the first reception quality (reception CIR 301) and the second reception quality (CIR 302) is calculated, a power value corresponding to the calculated difference is calculated as a power margin 303.

  Note that in order to calculate the power margin, the transmission power value in the base station apparatus necessary for the communication terminal apparatus to obtain the first reception quality and the base necessary for the communication terminal apparatus to obtain the second reception quality. After calculating the transmission power value in the station apparatus, the difference between the transmission power values may be calculated.

  Information regarding the power margin calculated as described above is output to the combining unit 215 as power margin information.

  The DRC signal creation unit 203 creates a DRC signal indicating the transmission rate calculated by the required modulation scheme determination unit 201. The created DRC signal is output to the synthesis unit 215.

  The combining unit 215 generates a combined signal by combining the DRC signal from the DRC signal generating unit 203 and the power margin information from the margin calculating unit 202. The generated combined signal is output to modulation section 204.

  The combined signal is modulated by modulation section 204, spread by spreading section 205, frequency-converted to a radio frequency by transmission RF section 206, and transmitted to base station apparatus by antenna 208 via duplexer 207.

  The signal transmitted by the communication terminal apparatus is received by the antenna 112 of the base station apparatus. A signal (reception signal) received by the antenna 112 is output to the reception RF unit 113 via the duplexer 111. The reception signal from the duplexer 111 is frequency-converted to baseband by the reception RF unit 113, despread by the despreading unit 114, and demodulated by the demodulation unit 115. As a result, the demodulating unit 115 generates a demodulated signal. The generated demodulated signal is output to DRC signal detection section 116 and power margin information detection section 117.

  The power margin information detection unit 117 detects power margin information from the demodulated signal from the demodulation unit 115. The detected power margin information is output to the power setting unit 118.

  The power setting unit 118 recognizes the power margin of each communication terminal device from the detected power margin information. Further, power setting section 118 sets the transmission power value of the transmission signal of each communication terminal apparatus in consideration of the recognized power margin of each communication terminal apparatus. Specifically, in communication using conventional HDR, the transmission power of the transmission signal of each communication terminal apparatus is always set to a predetermined transmission power value (constant), but in this embodiment, predetermined transmission power is used. A value obtained by subtracting the power margin of the communication terminal apparatus from the power value is set as the transmission power value of the transmission signal of this communication terminal apparatus. The transmission power value of the transmission signal of the communication terminal device set in this way is necessary for the communication terminal device to obtain the second reception quality when the transmission rate requested by the communication terminal device is applied. This corresponds to the transmission power value of the base station apparatus.

  Thus, the transmission power value of the transmission signal of each communication terminal device set by the power setting unit 118 is output to the power control unit 109.

  On the other hand, DRC signal detection section 116 detects a DRC signal from the demodulated signal generated by demodulation section 115. The detected DRC signal is output to allocation section 101.

  The allocation unit 101 allocates communication resources to each communication terminal apparatus based on the DRC signal transmitted by each communication terminal apparatus. Downlink transmission data transmitted from the base station apparatus to the communication terminal apparatus is stored in the buffer 102 until communication resources are allocated.

  Downlink transmission data output from the buffer 102 is encoded by an encoding method that can be received by the communication terminal device by the adaptive encoding unit 103, modulated by a modulation method that can be received by the communication terminal device by the adaptive modulation unit 104, The signal is spread by a spreading code that can be received by the communication terminal apparatus by adaptive spreading section 105 and output to multiplexing section 108. Multiplexing section 108 generates a transmission signal by time-multiplexing the spread pilot signal with the spread downlink transmission data.

  The transmission signal generated by multiplexing section 108 is amplified by power control section 109 so as to have the transmission power value set by power setting section 118. The amplified transmission signal is frequency-converted to a radio frequency by the transmission RF unit 110 and transmitted to each communication terminal apparatus by the antenna 112 via the duplexer 111.

  The signal transmitted by the base station apparatus is received by the antenna 208 of the communication terminal apparatus. A signal (reception signal) received by the antenna 208 is output to the reception RF unit 209 via the duplexer 207. The reception signal from the duplexer 207 is frequency-converted to baseband by the reception RF unit 209 and despread by the adaptive despreading unit 210. As a result, adaptive despreading section 210 extracts components other than pilot signals (components corresponding to data) in the received signals. Components other than the extracted pilot signal are demodulated by the adaptive demodulator 211 and decoded by the adaptive decoder 212. As a result, the received data is extracted.

  Next, the effect of the communication apparatus according to the present embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating a state in which the communication terminal apparatus including the communication apparatus according to the first embodiment of the present invention and the base station apparatus perform communication using HDR.

  4, base station apparatus 401 corresponds to the base station apparatus shown in FIG. 1, and communication terminal apparatuses 402 to 404 and communication terminal apparatuses 410 to 412 correspond to the communication terminal apparatus shown in FIG. It is assumed that the base station device 401 is currently communicating with the communication terminal devices 402 to 404 existing in the cell area 405 covered by the base station device 401. Note that the communication terminal apparatuses 410 to 412 exist in the range of the cell area 405 but are communicating with a base station apparatus other than the base station apparatus 401. Since the cell areas are normally designed to overlap, the communication terminal apparatuses 410 to 412 exist in an overlapping area between the cell area of the base station apparatus 401 and the cell area of a base station other than the base station apparatus 401. Will be.

  As described above, the base station apparatus 401 performs scheduling based on the communication mode selected by the communication terminal apparatuses 402 to 404, sets a transmission rate for each communication terminal apparatus, and communicates with the communication terminal apparatuses 402 to 404 through the control channel. A signal indicating the allocation of communication resources is notified. Furthermore, the base station apparatus 401 transmits data only to the corresponding communication terminal apparatus via the data channel at the allocated time.

  Here, as an example, attention is paid to the time during which the base station device 401 transmits data to the communication terminal device 402. According to the conventional method, when transmitting data to a predetermined communication terminal device, the base station device 401 is large so that reception quality in all communication terminal devices existing in the cell area 405 is sufficiently good. Shall. In this case, as described above, the communication terminal device receiving data from other base station devices among the communication terminal devices 410 to 412 is transmitted from the base station device 401 to the communication terminal device 402. The signal will cause interference.

  However, in the present embodiment, the base station apparatus 401 uses the transmission power value such that reception quality in all communication terminal apparatuses existing in the cell area 405 is sufficiently good with respect to the communication terminal apparatus 402. Do not send. That is, when the transmission rate requested by the communication terminal device 402 is applied, the base station device 401 performs communication with the minimum transmission power value necessary for the received signal characteristics of the communication terminal device 402 to satisfy the desired quality. Data is transmitted to the terminal device 402. This minimum required transmission power value corresponds to the minimum transmission power value required for the reception quality of the communication terminal apparatus existing in the area 406 to satisfy the desired quality.

  If the base station apparatus 401 transmits data to the communication terminal apparatus 402 using such a transmission power value, the base station apparatus 401 receives data from other base station apparatuses by the signal transmitted to the communication terminal apparatus 402. Interference received by the communication terminal devices 410 to 412 is suppressed. At this time, the communication terminal apparatus 402 can obtain a received signal that satisfies the desired quality.

  In parallel with the communication described above, the base station device 401 and the communication terminal devices 402 to 404 perform normal CDMA communication using a band different from the frequency band used for HDR. Needless to say.

  Further, in the present embodiment, the case where the base station apparatus transmits data to only one communication terminal apparatus at the same time has been described. However, in the present invention, the base station apparatus performs a plurality of communications at the same time. The present invention is also applicable when data is transmitted to the terminal device. In this case, it is possible to suppress the possibility that delayed waves of signals transmitted from the base station apparatus to the plurality of communication terminal apparatuses interfere with each other, so that the communication quality of the plurality of communication terminal apparatuses is kept good. be able to.

  As described above, in the present embodiment, during communication using HDR, the base station apparatus ensures that the reception quality of all communication terminal apparatuses existing in the cell covered by the base station apparatus is sufficiently good. Rather than transmitting data to the communication terminal apparatus using a simple transmission power value, the communication terminal apparatus uses the minimum transmission power value required for the received signal characteristics of the communication terminal apparatus to satisfy the desired quality. Send data to. Thereby, while maintaining the quality of the received signal in the communication terminal device at a desired quality, communication using other base station devices among the communication terminal devices existing in the area covered by the base station device is performed. Interference applied to the communication terminal device can be suppressed.

  In the present embodiment, the communication terminal apparatus determines the transmission rate and power margin based on the measured reception quality, and after the determined transmission rate and power margin are reported to the base station apparatus, the base station apparatus is notified. The case where the transmission power value of the transmission signal of this communication terminal apparatus is set using the transmission rate and the power margin described as an example, but the reception quality measured by the communication terminal apparatus is notified to the base station apparatus, and the base station apparatus However, the transmission power value of the transmission signal of this communication terminal apparatus may be set using the transmission rate and power margin determined based on the notified reception quality. Thereby, the scale and power consumption of the communication terminal device can be suppressed.

  Further, the power margin may be transmitted from the communication terminal device only when a DRC with the fastest transmission rate is requested. Thereby, the scale and power consumption of the communication terminal device can be suppressed. In this case, the fact that a high transmission rate can be requested means that the CIR is good, so there is a high possibility of being located near the base station. Therefore, the transmission power of the base station can be greatly reduced, and the effect of avoiding interference is great.

(Embodiment 2)
In the present embodiment, a case will be described in which a reduction in transmission power is considered in advance when DRC is selected in a communication terminal apparatus. Hereinafter, this embodiment will be described.

  First, the configuration of the communication terminal apparatus according to the present embodiment will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of the communication terminal apparatus according to the second embodiment of the present invention. 5 that are the same as those in the first embodiment (FIG. 2) are denoted by the same reference numerals as those in FIG. 2 and will not be described in detail.

  In FIG. 5, a DRC signal creation unit 501 creates a DRC signal using the transmission rate determined by the required modulation scheme determination unit 201 and the power margin information from the margin calculation unit 202. In addition, DRC signal creation section 501 outputs the created DRC signal to modulation section 502. Details of the DRC signal in this embodiment will be described later.

  Modulating section 502 modulates the DRC signal from DRC signal creating section 501 and outputs the modulated DRC signal to spreading section 205.

  Next, the configuration of the base station apparatus according to the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of the base station apparatus according to the second embodiment of the present invention. 6 that are the same as those in the first embodiment (FIG. 1) are denoted by the same reference numerals as those in FIG. 1 and will not be described in detail.

  In FIG. 6, the power setting unit 601 uses the DRC signal detected by the DRC signal detection unit 116 to set the transmission power value of the transmission signal of each communication terminal device, and sets the set transmission power value to the power control unit. To 602.

  The power control unit 602 amplifies the transmission data spread by the adaptive spreading unit 105 so that the transmission power value set by the power setting unit 601 is obtained, and outputs the amplified transmission data to the multiplexing unit 604.

  Power control section 603 amplifies the pilot signal spread by spreading section 107 so as to have a predetermined (constant) transmission power value, and outputs the amplified pilot signal to multiplexing section 604.

  The multiplexing unit 604 generates a multiplexed signal by multiplexing the transmission data amplified by the power control unit 602 and the pilot signal amplified by the power control unit 603, and transmits the generated multiplexed signal to the transmission RF unit 110. Output to.

  Next, operations performed between the communication terminal apparatus shown in FIG. 5 and the base station apparatus shown in FIG. 6 will be described. Detailed description of operations similar to those of the first embodiment in the present embodiment will be omitted, and only operations different from the first embodiment in the present embodiment will be described.

  In FIG. 5, as described in Embodiment 1, the required modulation method determination unit 201 determines a transmission rate that can be received by the communication terminal apparatus with a desired quality based on the CIR measured by the CIR measurement unit 214. It is determined. The transmission rate determined by the required modulation scheme determination unit 201 is output to the margin calculation unit 202 and the DRC signal creation unit 501.

  As described in the first embodiment, the margin calculating unit 202 calculates a power margin using the CIR measured by the CIR measuring unit 214 and the transmission rate determined by the required modulation scheme determining unit 201. Information on the calculated power margin is output to the DRC signal generation unit 501 as power margin information.

  The DRC signal creation unit 501 creates a DRC signal using the transmission rate determined by the required modulation scheme determination unit 201 and the power margin information from the margin calculation unit 202. Specifically, in the DRC signal creation unit 501, a DRC table indicating a DRC signal corresponding to the transmission rate and power margin information is prepared in advance, and the transmission rate from the required modulation scheme determination unit 201 and the margin calculation unit 202 are prepared. The DRC signal is uniquely determined based on the power margin information.

  Here, the DRC signal in the first embodiment is “indicating a transmission rate at which the communication terminal apparatus can receive with a desired quality”, whereas the DRC signal in the present embodiment is “(1 ) A transmission rate at which the communication terminal apparatus can receive with a desired quality, and (2) a power margin when this transmission rate is selected (this power margin is the same as that in the first embodiment) It is.

  A specific example of the DRC table used by the DRC signal creation unit 501 will be described with reference to FIG. FIG. 7 is a schematic diagram illustrating an example of a DRC table used by the communication terminal apparatus according to the second embodiment of the present invention.

  In the DRC table shown in FIG. 7, the modulation scheme (BPSK, QPSK, 16QAM, etc.) corresponding to the transmission rate determined by the required modulation scheme determination section 201, and the power margin information (0, 5, 10) from the margin calculation section 202. , 15 [dB], etc.) are associated with DRC signals (1 to 6).

  For example, a transmission rate corresponding to 16QAM is selected by the required modulation method determination unit 201 and a power margin of 5 [dB] is calculated by the margin calculation unit 202 (the desired quality can be obtained even if the transmission power is reduced by 5 [dB]). If it can be satisfied), a DRC signal having a signal content of “4” is determined.

  The DRC signal created by the DRC signal creation unit 501 in this way is modulated by the modulation unit 502 and then output to the spreading unit 205.

  In FIG. 6, the DRC signal detected by the DRC signal detection unit 116 is output to the allocation unit 101 and the power setting unit 601. Note that the assignment unit 101 performs processing as described in the first embodiment.

  In power setting section 601, the transmission power value of the transmission signal of each communication terminal apparatus is set based on the DRC signal from DRC signal detection section 116. Specifically, the power setting unit 601 recognizes a power margin corresponding to the DRC signal from the DRC signal detection unit 116 using the DRC table used by the communication terminal apparatus shown in FIG. Further, a value obtained by subtracting this power margin from a predetermined transmission power value is set as the transmission power value of the transmission signal of this communication terminal apparatus.

  For example, when the DRC signal of a certain communication terminal device is “4”, the power setting unit 601 recognizes that this communication terminal device has requested that the transmission power value be reduced by 5 [dB]. Thus, the transmission power value of the communication terminal apparatus is set to a value obtained by subtracting 5 [dB] from the predetermined transmission power value. The transmission power value set in this way is output to power control section 602.

  In the power control unit 602, the transmission data spread by the adaptive spreading unit 105 is amplified so as to have the transmission power value set by the power setting unit 601. The amplified transmission data is output to multiplexing section 604.

  In power control section 603, the pilot signal spread by spreading section 107 is amplified so as to always have a predetermined (substantially constant) transmission power value. The amplified pilot signal is output to multiplexing section 604.

  The transmission data amplified by the power control unit 602 and the pilot signal amplified by the power control unit 603 are multiplexed by the multiplexing unit 604. Thereby, a multiplexed signal is generated. The generated multiplexed signal is output to transmission RF section 110. The above is the operation performed between the communication terminal apparatus shown in FIG. 5 and the base station apparatus shown in FIG.

  As described above, in this embodiment, the communication terminal apparatus individually transmits information indicating the transmission rate (modulation scheme) and information indicating the power margin to the base station apparatus (Embodiment 1). Rather, the communication terminal device transmits information indicating a combination of a transmission rate (modulation method) and a power margin to the base station device. Thereby, it is possible to reduce the amount of information (information relating to the transmission rate and transmission power value) transmitted from the communication terminal device to the base station device, that is, the amount of information on the radio channel.

  For example, paying attention to the amount of information necessary for transmission of the power margin, in the first embodiment, if the power margin to be handled is a two-digit value (0 to 99 [dB]), the information amount of at least 7 bits can be obtained even with only the power margin. In contrast, in the second embodiment, 16 types of information indicating combinations of transmission rates and power margins can be transmitted with only a 4-bit information amount.

  In the present embodiment, the base station apparatus transmits a pilot signal (a signal used as a reference when measuring communication quality in a communication terminal apparatus: a reference signal) with a transmission power value being substantially constant. Since the terminal device can accurately measure the communication quality, it is possible to accurately perform DRC selection (selection of modulation scheme and power margin).

  Further, even when the base station apparatus transmits the pilot signal with the transmission power value kept substantially constant, the same effect as in the second embodiment can be obtained.

  In the embodiment of the present invention, a case has been described in which a DRC table in which a combination of a modulation scheme and a power margin is set in advance is used. However, the content of this DRC table (for example, the amount of power reduction during 16QAM transmission is reduced). 5 [dB], 10 [dB], etc.) may be broadcast from the base station apparatus to the communication terminal apparatus in advance through a broadcast channel or the like before communication is performed.

  Further, even during communication, it is possible to select an optimal power reduction amount by adaptively changing the contents of the DRC table for each communication terminal apparatus in accordance with various conditions such as communication quality.

  Further, in the present embodiment, a case has been described in which the communication terminal apparatus transmits a DRC signal indicating a combination of a transmission rate and a power margin. However, the communication terminal apparatus determines the transmission power value in the base station apparatus based on the power margin. The base station apparatus may calculate and transmit a DRC signal indicating a combination of the transmission rate and the calculated transmission power value, and the base station apparatus may set the transmission power value using the transmission power value in the DRC signal. .

(Embodiment 3)
In the present embodiment, when communication of transmission data to a communication terminal apparatus with good communication quality becomes dominant in the downlink (data channel) of the base station apparatus, transmission to the pilot signal and all communication terminal apparatuses A case where the data transmission power is lowered will be described.

  Transmission data for a communication terminal apparatus having good communication quality, that is, a communication terminal apparatus that is located near the base station apparatus (for example, a communication terminal apparatus that reports the DRC signals 4 to 6 in FIG. 7 to the base station apparatus). When communication is dominant in the downlink in the cell of the base station apparatus, the downlink is assigned to a communication terminal apparatus (communication terminal apparatus existing far from the base station apparatus) located at the end of this cell. It is thought that there is little being done. Even in such a case, in the conventional system, the base station apparatus transmits a pilot signal and transmission data using a constant power that reaches all the communication terminal apparatuses in the cell.

  However, in the above case, first of all, focusing attention on transmission data, the base station device is less likely to transmit the transmission data to a communication terminal device located far from the own station. Nevertheless, the transmission data is transmitted to the communication terminal apparatus existing at a position close to the own station by using a certain power so that the reception quality of the communication terminal apparatus is good. That is, the base station apparatus transmits transmission data to the communication terminal apparatus using transmission power more than necessary.

  As a result, the base station apparatus gives large interference to the communication terminal apparatus in a cell covered by another base station apparatus. In addition, when the base station apparatus performs HDR communication with respect to a plurality of communication terminal apparatuses at the same time, the base station apparatus greatly interferes with a plurality of communication terminal apparatuses existing in a cell covered by the base station apparatus.

  Secondly, in the above case, focusing on the pilot signal, the base station apparatus transmits the pilot signal using power that reaches all communication terminal apparatuses existing in the cell. Here, the base station apparatus is unlikely to transmit transmission data to a communication terminal apparatus that is located far from the own station. Therefore, if communication of transmission data to a communication terminal apparatus with good communication quality is limited only to the situation where it is dominant in the downlink of the base station apparatus, communication in which the base station apparatus exists at a position far from its own station. The need to transmit a pilot signal to the terminal device is low. Therefore, it can be said that the base station apparatus transmits a pilot signal using transmission power more than necessary.

  Furthermore, the fact that a base station apparatus transmits a pilot signal using transmission power more than necessary corresponds to interference with communication terminal apparatuses existing in cells of other base station apparatuses.

  Therefore, in the present embodiment, in order to prevent the above-described problem, when transmission of transmission data to a communication terminal apparatus with good communication quality becomes dominant in the downlink of the base station apparatus (that is, When the downlink has excessive quality), the base station apparatus not only lowers the transmission power of the transmission data to the communication terminal apparatus with good communication quality but also transmits the transmission power of the transmission data to other communication terminal apparatuses and The transmission power of the pilot signal is reduced by the same level as the transmission power of transmission data for a good communication terminal apparatus.

  That is, the base station apparatus reduces the cell radius (each communication terminal apparatus measures communication quality using the CIR of the pilot signal, so that the base station apparatus reduces the transmission power of the pilot signal Equivalent to reducing the cell size). In other words, the base station apparatus concentrates on the communication terminal apparatus that is selected as the transmission destination of the transmission data at a position close to the own station using power smaller than the normal transmission power. For communication terminal devices that transmit transmission data and are located at a position far from the own station, they are accommodated in a cell of another base station device, or transmission data to a communication terminal device located at a position close to the own station After the transmission is completed, transmission data is transmitted.

  Thereby, the base station apparatus can concentrate transmission data transmission to a communication terminal apparatus with good communication quality while suppressing interference with other cells.

  When the transmission of transmission data to the communication terminal apparatus with good communication quality decreases, the base station apparatus restores the transmission power of the transmission data and the transmission power of the pilot signal (returns the cell size to the original). The transmission data and the pilot signal are made to reach all communication terminals in the cell with sufficient quality. That is, at this time, the base station apparatus pays attention to the fact that most of the communication terminal apparatuses selected as transmission data transmission destinations are communication terminal apparatuses that are located far from the own station, and thus the transmission data and pilot Restore the signal transmission power.

  All base station apparatuses can control interference power with other base station apparatuses by controlling the transmission power as described above. Thereby, since all the base station apparatuses can reduce power consumption, radio resources can be utilized more effectively.

  Next, the configuration of the base station apparatus described above will be described with reference to FIG. FIG. 8 is a block diagram showing a configuration of the base station apparatus according to the third embodiment of the present invention. Here, as an example, the base station apparatus shown in FIG. 8 will be described in the case of communicating with the communication terminal apparatus shown in FIG. 5 using the DRC table shown in FIG. 7, but the base station apparatus shown in FIG. Any communication terminal apparatus that performs communication may be used as long as it has a configuration for reporting a DRC signal to the base station apparatus. 8 that are the same as those in FIG. 1 or FIG. 6 are denoted by the same reference numerals as those in FIG. 1 or FIG.

  Allocation section 101 decides allocation of communication resources to each communication terminal apparatus based on the DRC signal as in Embodiment 1 (transmission of transmission data to the communication terminal apparatus that has reported a high DRC signal) Are given priority).

  The downlink quality estimation section 801 uses the DRC signal from the DRC signal detection section 116 to communicate with a communication terminal apparatus that is located near the own station, that is, a communication terminal apparatus with good communication quality (the CIR of the pilot signal is predetermined). It recognizes how many communication terminal devices are larger than the value, generates information indicating transmission power based on the recognition result, and outputs the information to power setting section 802.

  Based on information from downlink quality estimation section 801, power setting section 802 sets a transmission power value for pilot signals and transmission data, and outputs the set transmission power value to power control section 109.

  Next, the operation of the base station apparatus having the above configuration will be described with reference to FIG. 9 in addition to FIG. FIG. 9 is a flowchart showing the operation of the base station apparatus according to the third embodiment of the present invention. Note that operations similar to those in the first embodiment or the second embodiment in this embodiment are omitted.

  In downlink quality estimation section 801, first, as shown in step (hereinafter referred to as “ST”) 901, the number of communication terminal apparatuses that have reported DRC value 6, or all communication in the cell of the own station. When the ratio of the communication terminal apparatus that has reported the DRC value 6 in the communication terminal apparatus (hereinafter simply referred to as “the number or ratio of the communication terminal apparatuses having the DRC value 6”) exceeds a predetermined value, it is shown in ST902. As described above, information instructing to lower the transmission power value by 15 [dB] from the normal value is output to the power setting unit 802. On the other hand, when the number or ratio of the communication terminal apparatuses with DRC value 6 is equal to or smaller than the predetermined value, the process proceeds to ST903.

  In ST903, when the number or ratio of communication terminal apparatuses having a DRC value of 5 or more exceeds a predetermined value, as shown in ST904, information indicating that the transmission power value is reduced by 10 [dB] from the normal power The data is output to the setting unit 802. On the other hand, when the number or ratio of the communication terminal devices having a DRC value of 5 or more is equal to or less than the predetermined value, the process proceeds to ST905.

  In ST905, when the number or ratio of communication terminal apparatuses having a DRC value of 4 or more exceeds a predetermined value, as shown in ST906, information instructing to lower the transmission power value by 5 [dB] from the normal level is included. The data is output to the setting unit 802. On the other hand, when the number or ratio of the communication terminal devices having the DRC value of 4 or more is equal to or less than the predetermined value, the process proceeds to ST907.

  In ST907, it is recognized that transmission data transmission to a communication terminal apparatus with good communication quality is not dominant in the downlink of the base station apparatus, and information indicating that the transmission power value is normal Is output to the power setting unit 802.

  Thereafter, power setting section 802 sets the transmission power value of the pilot signal and transmission data based on the information instructed by downlink quality estimation section 801. That is, based on information from downlink quality estimation section 801, 15 [dB] (ST902), 10 [dB] (ST904), 5 [dB] (ST906) and 0 [dB] are calculated from the normal transmission power value. By subtracting one of (ST907), the transmission power value of the pilot signal and transmission data is set. It goes without saying that the normal transmission power value here corresponds to a transmission power value that can be received with sufficient quality by all the communication terminal apparatuses existing in the cell of the own station.

  Note that the value to be subtracted from the normal transmission power value is set according to the size of the DRC value (ST902, ST904, ST906 and ST907 in FIG. 9) is the size of the DRC value reported by the communication terminal apparatus. That is, it is considered that the optimum value of the transmission power value for this communication terminal apparatus differs depending on the distance of the communication terminal apparatus from its own station. Thereby, the reception quality in the communication terminal device that receives the transmission data can be reliably kept good.

  Thereafter, the transmission signal generated by multiplexing section 108 (the signal in which the pilot signal and transmission data for each communication terminal apparatus are multiplexed) becomes the transmission power value set by power setting section 802 in power control section 109. As described above, the signal is uniformly amplified and output to the transmission RF unit 110.

  Next, the reason why not only the transmission power value of transmission data for all communication terminal apparatuses but also the transmission power value of pilot signals is reduced will be described. When the transmission power of the pilot signal is reduced to the normal value by reducing the transmission power value of the transmission data, the communication terminal device existing in the cell of another base station device receives the reception quality when the pilot signal is received. However, it may be lower than the reception quality when the transmission data is actually received. Therefore, these communication terminal apparatuses report to the base station apparatus a transmission rate that is lower than a transmission rate that is originally sufficient to satisfy predetermined reception quality. As a result, the total downlink throughput (total amount of transmission data transmitted to the communication terminal apparatus) in the other base station apparatus decreases.

  Therefore, in the present embodiment, transmission power values of transmission data and pilot signals for all communication terminal apparatuses are lowered by the same level. Thereby, it is possible to prevent a decrease in total throughput in other base station apparatuses.

  As described above, according to the present embodiment, the transmission data communication to the communication terminal apparatus with good communication quality (located near the base station apparatus) occupies the downlink, that is, the downlink. The base station apparatus determines the transmission power value of the transmission data for the pilot signal and all the communication terminal apparatuses according to the ratio of the communication to the transmission data to the communication terminal apparatus with good communication quality for In addition, it is possible to suppress interference with communication terminal apparatuses existing in the other cell and other station cells, and to improve the total downlink throughput (total amount of transmission data transmitted to the communication terminal apparatus).

  Specifically, when the ratio of the transmission data to the communication terminal device with good communication quality in the downlink is large, based on the distance from the own station of the communication terminal device with good communication quality, By reducing the transmission power value of the transmission data for the pilot signal and all communication terminal devices uniformly, the reception quality at the communication terminal device with the above good communication quality is kept good, and it exists in the cell of its own station and other stations Interference with the communication terminal device can be suppressed.

  On the other hand, when the ratio of transmission data to the communication terminal device with good communication quality in the downlink is small, the base station can reduce the transmission power value of the transmission data for the pilot signal and all communication terminal devices. Since the reception quality in many communication terminal devices located far from the station device is deteriorated, the total throughput of the downlink is reduced. Therefore, the transmission power value of the transmission data for the pilot signal and all communication terminal devices is normally set. To the value of. Thereby, the total throughput of the downlink can be increased, that is, the transmission efficiency can be improved.

(Embodiment 4)
In the present embodiment, a case will be described in Embodiment 3 where the transmission power values of the pilot signal and transmission data are made close to normal transmission power values in accordance with changes in the total throughput in the downlink.

  In Embodiment 3 described above, the transmission power values of the pilot signal and transmission data are lowered according to the ratio of transmission data communication to communication terminal apparatuses with good communication quality in the downlink. However, by reducing the transmission power value of transmission data, a large number of packets that are not correctly received may be generated in the communication terminal apparatus, which may reduce the total downlink throughput. As a result, inefficient transmission is performed.

  Therefore, in the present embodiment, whether or not the total throughput of the downlink can be maintained is monitored, and when the total throughput of the downlink decreases after the transmission power value of the transmission data is decreased, the transmission data The transmission power value is brought close to a normal value.

  Hereinafter, the configuration of the base station apparatus according to the present embodiment will be described with reference to FIG. FIG. 10 is a block diagram showing a configuration of a base station apparatus according to Embodiment 4 of the present invention. 10 that are the same as those in the third embodiment (FIG. 8) are denoted by the same reference numerals as those in FIG. 8, and detailed descriptions thereof are omitted.

  In FIG. 10, the allocating unit 1001 has the same configuration as the allocating unit 101 in the third embodiment except for the following points. That is, allocating section 1001 uses the transmission resource allocation result (which communication terminal apparatus performs transmission at which transmission rate) determined based on the DRC signal to estimate the downlink quality. Output to the unit 1002.

  Downlink quality estimation section 1002 has the same configuration as downlink quality estimation section 801 in Embodiment 3 except for the following points. That is, downlink quality estimation section 1002 uses the allocation result from allocation section 1001 to monitor the change in total throughput of the entire downlink, and based on the recognition result described in Embodiment 3 and the change in total throughput. Information for instructing transmission power is generated and output to the power setting unit 802.

  Next, the operation of the base station apparatus having the above configuration will be described with reference to FIG. 11 in addition to FIG. FIG. 11 is a flowchart showing the operation of the base station apparatus according to the fourth embodiment of the present invention. Detailed description of the same operations in FIG. 11 as those in FIG. 9 will be omitted.

  After the transmission power value is reduced by 15 [dB] from ST902 in ST902, as shown in ST1101, downlink quality estimation section 1002 monitors the total downlink throughput based on the allocation result from allocation section 1001. Then, it is determined whether or not the total throughput is lower than before the transmission power is reduced. If the total throughput has not decreased, the process moves to ST901 described above. If the total throughput has decreased, the process moves to ST904 described above.

  Similarly, after the transmission power value is reduced by 10 [dB] from normal in ST904, as shown in ST1102, downlink quality estimation section 1002 determines whether or not the total throughput is lower than before the transmission power is reduced. Is determined. If the total throughput has not decreased, the process moves to ST901 described above. If the total throughput has decreased, the process moves to ST906 described above.

  Similarly, after the transmission power value is decreased by 5 [dB] from normal in ST906, as shown in ST1103, downlink quality estimation section 1002 determines whether or not the total throughput is lower than before the transmission power is decreased. Is determined. If the total throughput has not decreased, the process moves to ST901 described above. If the total throughput has decreased, the process moves to ST907 described above.

  In this embodiment, when the total throughput after the transmission power value is lowered cannot be maintained at the total throughput before the transmission power value is lowered, the transmission power is gradually approached to a normal value (steps). However, the transmission power value may be directly returned to a normal value.

  As described above, according to the present embodiment, in accordance with the change in the total downlink throughput, the transmission power value of the pilot signal and transmission data is brought close to a normal value, thereby reducing the transmission data due to lowering the transmission data. A decrease in the total throughput of the line can be prevented. Thereby, efficient transmission of transmission data can be realized.

(Embodiment 5)
In the present embodiment, based on the number of communication terminal devices from which the base station device has reported a predetermined DRC signal, communication terminal devices with good communication quality (communication terminal devices that are close to the own station) It is detected whether communication of transmission data is dominant in the downlink (that is, whether the downlink is excessive quality), and further, based on the detection result, the pilot signal and all communication terminals A case where the transmission power of transmission data to the apparatus is changed will be described.

  In Embodiment 3 described above, whether or not transmission data communication with a communication terminal apparatus with good communication quality is dominant in the downlink in the cell of the base station apparatus is a communication terminal that is a transmission destination of the transmission data Detection is performed using the ratio between the total number of devices and the number of communication terminal devices that have reported a predetermined DRC signal.

  However, for example, when the total number of communication terminal devices to which transmission data is transmitted is small, when the transmission power of the transmission data for the pilot signal and all communication terminal devices is reduced due to the above ratio exceeding the threshold, Total throughput may be reduced.

  Therefore, in the present embodiment, based on the number of communication terminal apparatuses that have reported a predetermined DRC signal, it is detected whether communication to a communication terminal apparatus with good communication quality is dominant in the downlink. Then, the transmission power of the transmission data for the pilot signal and all communication terminal apparatuses is changed based on the detection result.

  Specifically, for example, when the number of communication terminal devices that have reported a predetermined DRC signal is equal to or greater than a threshold value, communication to a communication terminal device with good communication quality is dominant in the downlink. In order to recognize this and prevent transmission using more transmission power than necessary, the transmission power is reduced. Conversely, when the number of communication terminal devices that have reported a predetermined DRC signal is below the threshold, many of the communication terminal devices that are transmission destinations of transmission data exist at positions far from the own station. And the transmission power is returned to the normal power value.

  As a result, it is possible to suppress interference with communication terminal apparatuses existing in the cell of the local station and the cell of other stations and improve the total downlink throughput.

  Next, configurations of the communication terminal apparatus and the base station apparatus according to the present embodiment will be described using FIG. 12 to FIG. 14. FIG. 12 is a block diagram showing a configuration of a communication terminal apparatus according to Embodiment 5 of the present invention. FIG. 13 is a schematic diagram illustrating an example of a DRC signal used by the communication terminal apparatus according to the fifth embodiment of the present invention. FIG. 14 is a block diagram showing a configuration of a base station apparatus according to the fifth embodiment of the present invention.

  First, the configuration of the communication terminal apparatus will be described with reference to FIG. 12, the same reference numerals as those in FIG. 5 are given, and detailed description thereof is omitted.

  The DRC signal creation unit 1201 creates a DRC signal using the transmission rate determined by the required modulation scheme determination unit 201. Specifically, the DRC signal creation unit 1201 has a DRC table (for example, the DRC table shown in FIG. 13) indicating the DRC signal corresponding to the transmission rate, and the transmission rate determined by the required modulation scheme determination unit 201. A DRC signal corresponding to is created. The DRC signal creation unit 1201 outputs the created DRC signal to the modulation unit 502.

  Next, the configuration of the base station apparatus will be described with reference to FIG. In FIG. 14, the same components as those in FIG. 8 are denoted by the same reference numerals as those in FIG.

  Downlink quality estimation section 1401 uses a DRC signal from DRC signal detection section 116 to establish a communication terminal apparatus that is close to its own station, that is, a communication terminal apparatus with good communication quality (CIR of the pilot signal is predetermined). The number of communication terminal devices) larger than the value is recognized, and the recognized number is compared with a threshold value. This downlink quality estimation section 1401 generates information indicating transmission power based on the comparison result, and outputs the generated information to the power setting section 802.

  Next, operations of the communication terminal apparatus and the base station apparatus having the above configurations will be further described with reference to FIG. FIG. 15 is a flowchart showing the operation of the base station apparatus according to the fifth embodiment of the present invention. In addition, about the operation | movement similar to Embodiment 1-Embodiment 4 in this Embodiment, it abbreviate | omits.

  In the communication terminal apparatus shown in FIG. 12, DRC signal creation section 1201 generates a DRC signal corresponding to the transmission rate determined by required modulation scheme determination section 201 in accordance with the DRC table shown in FIG. The generated DRC signal is output to modulation section 502.

  The operation in the base station apparatus shown in FIG. 14 is as follows. That is, downlink quality estimation section 1401 first recognizes the number of communication terminal apparatuses that have reported DRC value 3 using the DRC signal from DRC signal detection section 116, as shown in ST1501. A comparison is made between the number obtained and the threshold.

  As a result of this comparison, if the number of communication terminal devices that have reported DRC value 3 is equal to or greater than the threshold value, transmission data to a communication terminal device with good communication quality (communication terminal device that has reported DRC value 3) As shown in ST1502, information indicating that the transmission power is to be reduced by 1 [dB], for example, is generated. Conversely, when the number of communication terminal devices that have reported the DRC value 3 is below the threshold value, most of the communication terminal devices that are transmission destinations of transmission data exist at positions far from the own station. The apparatus is recognized as an apparatus, and the process moves to ST1503.

  In ST1503, it is determined whether or not the current transmission power value is a normal transmission power value (maximum value). If the current transmission power value is smaller than the normal transmission power value, information indicating that the transmission power is to be increased by 1 [dB], for example, is generated as shown in ST1504. Conversely, if the current transmission power value is a normal transmission power value, information indicating that the transmission power is not changed is generated, and the process moves to ST1501.

  Information generated by downlink quality estimation section 1401 as described above is output to power setting section 802. Power setting section 802 sets pilot signal and transmission data transmission power values based on information instructed by downlink quality estimation section 1401.

  As described above, in the present embodiment, the base station device transmits the pilot signal and all the communication terminal devices according to the number of communication terminal devices having good communication quality (located at a position close to the base station device). By determining the transmission power value of this transmission data, it is possible to suppress interference with communication terminal apparatuses existing in the cell of the local station and the cells of other stations and improve the total throughput of the downlink.

  Specifically, when the number of communication terminal devices with good communication quality is equal to or greater than the threshold, the communication quality is good by uniformly reducing the transmission power value of transmission data for pilot signals and all communication terminal devices. It is possible to suppress interference with the communication terminal apparatus existing in the cell of the local station and the cell of the other station while maintaining good reception quality in a simple communication terminal apparatus.

  Conversely, when the number of communication terminal devices with good communication quality is below the threshold, the transmission power value of the transmission data for the pilot signal and all communication terminal devices is kept low, and the communication terminal device exists at a position far from the base station device. Since the reception quality in many communication terminal apparatuses deteriorates, the total downlink throughput decreases, so the transmission power value of transmission data for pilot signals and all communication terminal apparatuses is brought closer to the normal transmission power value. . Thereby, the total throughput of the downlink can be increased, that is, the transmission efficiency can be improved.

  Furthermore, according to the present embodiment, when the total number of communication terminal devices that are transmission destinations of transmission data is small, the transmission power is changed based on the number of communication terminal devices with good communication quality. Compared to mode 3, it is possible to suppress a decrease in the total downlink throughput.

  In the present embodiment, the case where the communication terminal apparatus reports a DRC signal designating only the modulation scheme to the base station apparatus has been described as an example. However, the present invention is not limited to the communication terminal apparatus. Needless to say, the present invention can also be applied to the case of reporting a DRC signal as described in the first to fourth embodiments.

  Further, in this embodiment, in order to prevent a decrease in the total throughput of the downlink due to a small total number of communication terminal apparatuses that are transmission data transmission destinations, Although the case where the transmission power is changed based on the number has been described, as in the third embodiment, the number of communication terminal apparatuses having good communication quality and the total number of communication terminal apparatuses serving as transmission destinations of transmission data It goes without saying that the transmission power can be changed based on the ratio.

(Embodiment 6)
In the present embodiment, a case will be described in Embodiment 5 where the transmission power values of the pilot signal and transmission data are made close to normal transmission power values in accordance with changes in the total throughput in the downlink.

  In the fifth embodiment, the transmission power values of the pilot signal and transmission data are lowered according to the number of communication terminal apparatuses with good communication quality. However, as described in the fourth embodiment, by reducing the transmission power value of the transmission data, a large number of packets that are not correctly received may be generated in the communication terminal apparatus, and the total downlink throughput may be reduced. As a result, inefficient transmission is performed.

  Therefore, in the present embodiment, as in the case of Embodiment 4, it is monitored whether the total downlink throughput is maintained, and the total downlink throughput decreases after the transmission power value of transmission data is lowered In this case, the transmission power value of the transmission data is brought close to a normal value.

  Hereinafter, the configuration of the base station apparatus according to the present embodiment will be described with reference to FIG. FIG. 16 is a block diagram showing a configuration of a base station apparatus according to Embodiment 6 of the present invention. In FIG. 16, the same components as those in FIGS. 10 and 14 are denoted by the same reference numerals as those in FIGS. 10 and 14, and detailed description thereof is omitted.

  In FIG. 16, downlink quality estimation section 1601 has the same configuration as downlink quality estimation section 1401 in Embodiment 5 except for the following points. That is, downlink quality estimation section 1601 uses the allocation result from allocation section 1001 to monitor the change in total throughput of the entire downlink, and based on the comparison result described in Embodiment 5 and the change in this total throughput. Information for instructing transmission power is generated and output to the power setting unit 802.

  The configuration of the communication terminal apparatus according to the present embodiment is the same as that of the fifth embodiment (FIG. 12), and thus detailed description thereof is omitted.

  Next, the operation of the base station apparatus having the above configuration will be further described with reference to FIG. FIG. 17 is a flowchart showing the operation of the base station apparatus according to the sixth embodiment of the present invention. Note that detailed description of operations similar to those in FIG. 15 in FIG. 17 is omitted.

  After the transmission power value is reduced by 1 [dB] in ST1502, as shown in ST1701, downlink quality estimation section 1601 monitors the total downlink throughput based on the allocation result from allocating section 1001, and transmits It is determined whether the total throughput is lower than before the power is reduced. If the total throughput has not decreased, the process moves to ST1501 described above. If the total throughput has decreased, the process moves to ST1504 described above.

  In this embodiment, when the total throughput after the transmission power value is lowered cannot be maintained at the total throughput before the transmission power value is lowered, the transmission power is gradually approached to a normal value (steps). However, the transmission power value may be directly returned to a normal value.

  As described above, according to the present embodiment, in accordance with the change in the total downlink throughput, the transmission power value of the pilot signal and transmission data is brought close to a normal value, thereby reducing the transmission data due to lowering the transmission data. A decrease in the total throughput of the line can be prevented. Thereby, efficient transmission of transmission data can be realized.

(Embodiment 7)
In the present embodiment, as an index for detecting whether or not the downlink (data channel) has an excessive quality, in addition to using only the number or ratio of communication terminal apparatuses that report the highest DRC value, The case where the distribution of DRC values reported by the terminal device is used will be described.

  FIG. 18A is a schematic diagram conceptually illustrating a first example of the distribution of DRC values reported by the communication terminal apparatus according to Embodiment 7 of the present invention. FIG. 18B is a schematic diagram conceptually illustrating a second example of the distribution of DRC values reported by the communication terminal apparatus according to Embodiment 7 of the present invention. In FIG. 18A and FIG. 18B, for each DRC value shown on the horizontal axis, the number of communication terminal apparatuses that have reported the DRC value is shown on the vertical axis.

  As shown in FIG. 18 (a), when the distribution of DRC values is extremely biased toward the higher one (higher transmission rate), it is estimated that the downlink of the cell is of excessive quality. be able to. That is, since the base station apparatus performs transmission using transmission power more than necessary, the base station apparatus gives large interference to communication terminal apparatuses existing in the cell of the local station and the cells of other stations.

  Therefore, in such a case, by reducing the transmission power of the pilot signal and transmission data, as shown in FIG. 18B, the DRC value distribution is not extremely biased toward the higher one (that is, communication). The communication of transmission data to a communication terminal apparatus with good quality is not dominant in the downlink). Thereby, the interference with respect to the communication terminal apparatus which exists in the cell of an own station and the cell of another station can be suppressed.

  Hereinafter, the structure of the base station apparatus concerning this Embodiment is demonstrated. The configuration of the base station apparatus according to the present embodiment is the same as that shown in FIG. 14 except that the downlink quality estimation unit has the following configuration.

  That is, the downlink quality estimation unit uses the DRC signal from the DRC signal detection unit 116 to calculate the average value and variance of the DRC value (in other words, the reception quality of the pilot signal in each communication terminal apparatus), and the calculation result Based on the above, the distribution state of the DRC value is determined. The downlink quality estimation unit generates information indicating transmission power based on the distribution state determination result, and outputs the generated information to power setting unit 802.

  Next, the operation of the base station apparatus according to this embodiment will be further described with reference to FIG. FIG. 19 is a flowchart showing the operation of the base station apparatus according to Embodiment 7 of the present invention. Note that the description of the same operation as that of the fifth embodiment in this embodiment is omitted.

  In the downlink quality estimation unit, first, the average value and variance of the DRC values reported by each communication terminal apparatus are calculated. In ST1901, it is determined whether or not the calculated average value is equal to or greater than a threshold value. If the calculated average value is equal to or greater than the threshold value, the process proceeds to ST1902, and if it is less than the threshold value, the process is performed. Moves to ST1904.

  In ST1902, it is determined whether or not the variance of the calculated DRC value is less than or equal to a threshold value. If the calculated variance is less than or equal to the threshold value, the process proceeds to ST1903, and if greater than the threshold value, the process is performed. Moves to ST1904.

  In ST1903, it is recognized that the calculated average value is greater than or equal to the threshold value and the calculated variance is less than or equal to the threshold value, so that the DRC distribution is extremely biased toward the higher side. For this reason, information instructing to reduce the transmission power by 1 [dB], for example, is generated.

  On the other hand, in ST1904, when the calculated average value is less than the threshold value or the calculated variance is larger than the threshold value, it is recognized that the DRC distribution is not extremely biased toward the higher one. Furthermore, it is determined whether or not the current transmission power value is a normal transmission power value (maximum value). If the current transmission power value is a normal transmission power value, the process moves to ST1901, and if it is less than the normal transmission power value, the process moves to ST1905. In ST1905, information instructing to increase the transmission power by 1 [dB], for example, is generated.

  Information generated in ST1903 or ST1905 is output to power setting section 802.

  As described above, in the present embodiment, by using the distribution of DRC values reported by the communication terminal device, whether or not the downlink has excessive quality, that is, to the communication terminal device having good communication quality. It is possible to reliably detect whether or not transmission data transmission is dominant in the downlink.

(Embodiment 8)
In the present embodiment, a case will be described in Embodiment 7 where the transmission power value is controlled in accordance with the average value of DRC values and the magnitude of dispersion.

  In the seventh embodiment, when the distribution state of the DRC value is detected using the average value and the variance of the DRC value, and the distribution state of the DRC is extremely biased to the higher side using the detected distribution state, When the transmission power is lowered by 1 [db] and the DRC distribution is not extremely biased toward the higher one, the transmission power is increased by 1 [dB] so as to approach the normal transmission power value.

  However, even in a situation where the DRC distribution is biased toward the higher one, there is a first case where the DRC distribution is biased toward a higher DRC value, or a DRC distribution that is smaller than the first case. There is a second case where it is biased. The optimum reduction amount of the transmission power value differs depending on whether the DRC distribution state is in the first case or in the second case. That is, it is preferable that the optimal reduction width in the second case is smaller than the optimal reduction width in the first case from the viewpoint of interference with communication terminals in other cells and the total throughput.

  Similarly, in situations where the DRC distribution is biased toward the lower side, the DRC distribution may be biased toward a lower DRC value, and in some cases, the DRC distribution is higher than in the third case. There is also a fourth case that is biased toward. The optimum increase in the transmission power value differs depending on whether the DRC distribution state is in the third case or the fourth case. That is, it is preferable that the optimum increase amount in the third case is larger than the increase amount in the fourth case from the viewpoint of interference with the communication terminal apparatus in other cells and the total throughput.

  Therefore, in the present embodiment, after determining which DRC value is extremely biased based on the distribution state of DRC values detected using the average value and variance of DRC values, the determination result The transmission power value is controlled in accordance with the control (that is, the increase or decrease range is controlled).

  Hereinafter, the structure of the base station apparatus concerning this Embodiment is demonstrated. The configuration of the base station apparatus according to the present embodiment is the same as that shown in FIG. 14 except that the downlink quality estimation unit has the following configuration.

  That is, the downlink quality estimation unit uses the DRC signal from the DRC signal detection unit 116 to calculate the average value and variance of the DRC value (in other words, the reception quality of the pilot signal in each communication terminal apparatus), and the calculation result Based on the above, the distribution state of DRC values (specifically, which DRC value is biased) is determined. The downlink quality estimation unit generates information indicating transmission power based on the distribution state determination result, and outputs the generated information to power setting unit 802.

  Next, the operation of the base station apparatus according to this embodiment will be described with reference to FIG. 20 and FIG. FIG. 20 is a schematic diagram illustrating an example of a relationship between an average value and variance of DRC values and a transmission power value in the base station apparatus according to the eighth embodiment of the present invention. FIG. 21 is a flowchart showing the operation of the base station apparatus according to Embodiment 8 of the present invention. Detailed description of the same operations as those of the seventh embodiment in the present embodiment is omitted.

  In the downlink quality estimation unit, first, the average value and variance of the DRC values reported by each communication terminal apparatus are calculated. Further, information indicating transmission power is generated according to the relationship shown in FIG. 20 using the calculated average value and variance.

  Specifically, in ST2101, it is determined whether or not the average value and variance of the DRC values are in region 6 shown in FIG. When the average value and the variance are in region 6 (that is, when the highest DRC value is biased), after the information that the transmission power is reduced by 10 [dB] is generated in ST2102, the process proceeds to ST2101. Return to. Conversely, if the average value and the variance are not in region 6, the process moves to ST2103.

  In ST2103, it is determined whether the average value and variance of the DRC values are in region 5. When the average value and the variance are in region 5 (that is, when the DRC value is biased lower than that in region 6), information indicating that the transmission power is reduced by 6 [dB] is generated in ST2104. The process returns to ST2101. Conversely, if the average value and variance are not in region 5, the process moves to ST2105.

  In ST2105, it is determined whether or not the average value and variance of the DRC values are in region 4. When the average value and the variance are in the region 4 (that is, when a bias is generated in the DRC value lower than that in the region 5), after the information to reduce the transmission power by 3 [dB] is generated, Moves to ST2101. Conversely, if the average value and the variance are not in region 4, the process proceeds to ST2107.

  In ST2107, it is determined whether or not the average value and variance of the DRC values are in region 3. If the average value and variance are in region 3 (ie most preferred when none of the DRC values are biased), no information is generated to indicate whether to increase or decrease the transmit power, and the process Move on to ST2101. Conversely, if the average value and the variance are not in region 3, the process moves to ST2108.

  In ST2108, it is determined whether the average value and variance of the DRC values are in region 2. When the average value and the variance are in region 2 (that is, when the low DRC value is biased), in ST2109, it is determined whether or not the current transmission power value is a normal transmission power value. The When the current transmission power value is a normal transmission power value, information indicating that the transmission power is changed is not generated, and the process returns to ST2101. If the current transmission power value is not a normal transmission power value, information instructing to increase the transmission power by 3 [dB] is generated in ST2110, and then the process returns to ST2101.

  On the other hand, when the average value and the variance are not in region 2 in ST2108, the process proceeds to ST2111.

  In ST2111, it is determined whether the average value and variance of DRC values are in region 1. If the average value and the variance are in region 1 (that is, if the DRC value is lower than in region 2), whether or not the current transmission power value is a normal transmission power value in ST2112 Is determined. When the current transmission power value is a normal transmission power value, information indicating that the transmission power is changed is not generated, and the process returns to ST2101. If the current transmission power value is not a normal transmission power value, information instructing to increase the transmission power value by 6 [dB] is generated in ST2113, and then the process proceeds to ST2101.

  Thus, in this embodiment, after determining which DRC value is extremely biased using the average value and variance of DRC values, transmission power is controlled based on the determination result. As a result, it is possible to reduce interference with communication terminals in other cells and improve total throughput at high speed and with high accuracy.

  In addition, when all the base station apparatuses perform the control described in the first to eighth embodiments, the area where the areas of the base station apparatuses overlap can be reduced. Although the throughput may be reduced for a moment when the transmission power is reduced, the throughput of the entire system can be maximized in the long run.

  Further, the base station apparatus and communication terminal apparatus described in Embodiments 1 to 8 can be used in combination.

101, 1001 Allocation unit 102 Buffer 103 Adaptive encoding unit 104 Adaptive modulation unit 105 Adaptive spreading unit 108 Multiplexing unit 109 Power control unit 110 Transmission RF unit 115 Demodulation unit 116 DRC signal detection unit 117 Power margin information detection unit 118, 802 Power setting unit 201 Request Modulation Method Determination Unit 202 Margin Calculation Unit 203 DRC Signal Creation Unit 213 Despreading Unit 214 CIR Measurement Units 801, 1002, 1401, 1601 Downlink Quality Estimation Unit

Claims (7)

A table in which a plurality of combinations of modulation schemes, transmission power adjustment values, and information corresponding to combinations of modulation schemes and transmission power adjustment values are set;
Receiving means for receiving a signal from a communication partner;
Transmission means for transmitting the information corresponding to the reception quality of the received signal to the communication partner based on the table;
The information is
When the reception quality is a predetermined value, it indicates a predetermined modulation multi-level modulation scheme and a predetermined transmission power,
When the received quality is lower than the predetermined value, the modulation scheme of the modulation multi-value number smaller than the predetermined modulation multi-value number and the predetermined transmission power,
When the reception quality is higher than the predetermined value, the transmission power is smaller than the predetermined modulation scheme and the predetermined transmission power,
Wireless communication device. When the reception quality is lower than the predetermined value, the information indicates a modulation scheme in which the modulation multi-value number is smaller as the reception quality is lower.
The wireless communication apparatus according to claim 1. When the reception quality is higher than the predetermined value, the information indicates smaller transmission power as the reception quality is higher.
The wireless communication apparatus according to claim 1. A receiving step for receiving a signal from a communication partner;
Based on a table in which a plurality of combinations of modulation schemes, transmission power adjustment values, and information corresponding to combinations of modulation schemes and transmission power adjustment values are set, the information corresponding to the reception quality of the received signal is stored in the communication partner. A transmission step of transmitting to
The information is
When the reception quality is a predetermined value, it indicates a predetermined modulation multi-level modulation scheme and a predetermined transmission power,
When the received quality is lower than the predetermined value, the modulation scheme of the modulation multi-value number smaller than the predetermined modulation multi-value number and the predetermined transmission power,
When the reception quality is higher than the predetermined value, the transmission power is smaller than the predetermined modulation scheme and the predetermined transmission power,
Wireless communication method. When the reception quality is lower than the predetermined value, the information indicates a modulation scheme in which the modulation multi-value number is smaller as the reception quality is lower.
The wireless communication method according to claim 4. When the reception quality is higher than the predetermined value, the information indicates smaller transmission power as the reception quality is higher.
The wireless communication method according to claim 4. A wireless communication system comprising a base station device and a communication terminal device,
The communication terminal device
A table in which a plurality of combinations of modulation schemes, transmission power adjustment values, and information corresponding to combinations of modulation schemes and transmission power adjustment values are set;
Receiving means for receiving a signal from the base station apparatus;
Transmission means for transmitting the information corresponding to the reception quality of the received signal to the base station apparatus based on the table,
The base station apparatus includes a control unit that controls a modulation scheme and transmission power based on the information from the communication terminal apparatus,
The information is
When the reception quality is a predetermined value, it indicates a predetermined modulation multi-level modulation scheme and a predetermined transmission power,
When the received quality is lower than the predetermined value, the modulation scheme of the modulation multi-value number smaller than the predetermined modulation multi-value number and the predetermined transmission power,
When the reception quality is higher than the predetermined value, the transmission power is smaller than the predetermined modulation scheme and the predetermined transmission power,
Wireless communication system.

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