JP2003298510A - Method for controlling transmission power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication terminal apparatus for making communication with other base station apparatus by using the technique HDR (High Data Rate) and to suppress interference with the communication terminal apparatus making communication using the HDR with its own base station at the same time. <P>SOLUTION: The base station apparatus of this invention includes: a transmission rate setting means for setting a transmission rate of a transmission signal to the communication terminal apparatus on the basis of actual reception quality of the communication terminal apparatus; a power value setting means for setting a minimum transmission power value at which the characteristic of a received signal of the communication terminal apparatus for receiving the transmission signal at the set transmission rate satisfies desired quality as a transmission power value to the communication terminal apparatus; and a transmission means for transmitting the transmission signal at the set transmission rate to the communication terminal apparatus by using the set transmission power value. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control method used in a cellular communication system.

[0002]

2. Description of the Related Art 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 improve 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 in which communication resources are time-divided and scheduled to be allocated to each communication terminal, and a transmission rate is set for each communication terminal according to communication quality to improve data transmission efficiency.

Hereinafter, communication using HDR will be described with reference to FIG.
2 is used for the explanation. In FIG. 22, the base station 11 is
It is assumed that communication is currently being performed with the communication terminals 12 to 14 existing in the cell area 15 covered by this base station 11. Although the communication terminals 20 to 22 exist within the range of the cell area 15, they communicate with base stations (not shown) other than the base station 11.

First, the base station 11 transmits a pilot signal to the communication terminals 12-14. The communication terminals 12 to 14 use the pilot signal transmitted to the base station 11 to determine the CIR.
The communication quality is estimated by (desired wave-to-interference ratio) and the like, and the communicable transmission rate is obtained. Furthermore, the communication terminals 12 to 1
4 is a packet length based on the communicable transmission rate,
A communication mode indicating a combination of error correction and modulation method is selected, and a signal indicating the communication mode is transmitted 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 allocates communication resources to the communication terminals 12 to 14 through the control channel. The signal shown is notified.

The base station 11 is
Data is transmitted via the data channel only to the corresponding communication terminal. For example, the time t1 is the communication terminal 12
, The base station 11 transmits data only to the communication terminal 12 and does not transmit data to the communication terminals 13 and 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 above-described communication, the base station 11 and the communication terminals 12 to 14 use a band different from the frequency band used for the HDR, and use the normal CDMA. (Code Division Multiple Acces
s) method of communication.

[0009]

However, the above-mentioned conventional communication using HDR has the following problems. That is, referring again to FIG. 22, 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 set to be large so that the reception quality in all the communication terminals existing in the cell area 15 is sufficiently good.

For this reason, among communication terminals performing HDR communication with a base station other than the base station 11 (hereinafter referred to as “other base station”), it exists in the cell area 15 covered by the base station 11. Communication terminal (in FIG. 22, the communication terminal 20
22 to 22) may be interfered by the signal transmitted from the base station 11 to any of the communication terminals 12 to 14. As a result, the reception quality of the communication terminal affected by the interference as described above deteriorates. For example, when the time when the base station 11 transmits data to the communication terminal 12 via the data channel and the time when another base station transmits data to the communication terminal 20 via the data channel match. The communication terminal 20 is interfered by the 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, the communication terminals 12 to 14) at the same time (it is possible that such HDR transmission will be realized in the future). However, since the delayed waves of the signals transmitted to the plurality of communication terminals interfere with each other, the communication quality of the plurality of communication terminals deteriorates.

[0012] As described above, in the conventional communication using HDR, the base station performing the communication using HDR is
There is a problem that it may give interference to a communication terminal that communicates with another base station using HDR, or a communication terminal that communicates with its own station at the same time.

The present invention has been made in view of the above points, and a communication terminal device that performs communication with another base station device using HDR, and a communication using the HDR with its own station at the same time. It is an object of the present invention to provide a transmission power control method that suppresses interference on a communication terminal device that is performing

[0014]

The transmission power control method of the present invention is a transmission power control method for a downlink signal transmitted using any one of the modulation schemes determined from a plurality of modulation schemes having different modulation multi-value numbers. Therefore, with a modulation method other than the modulation method with the maximum modulation multi-valued number, the modulation multi-valued number is increased as the downlink quality is improved with the transmission power kept constant, and the modulation with the maximum modulation multi-valued number is increased. In the scheme, the transmission power is reduced as the downlink quality is improved while the modulation scheme is fixed.

The transmission control method of the present invention is a transmission control method for a downlink signal, and when the downlink quality is worse than a predetermined value, the first modulation number is changed while keeping the transmission power constant. If control is performed and the downlink quality is better than a predetermined value, the transmission power is changed while the modulation method is fixed.
Was controlled.

According to these methods, it is possible to perform transmission with the minimum transmission power that can satisfy the quality at the time of HDR transmission. Therefore, while maintaining the transmission quality for a desired communication terminal device, another base station device It is possible to reduce interference with a communication terminal device that performs HDR communication with and a communication terminal device that communicates with its own station at the same time.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below 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, the signals communicated via the control and data channels are
These 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 including a communication apparatus according to Embodiment 1 of the present invention. In FIG. 1, the allocation unit 101
Is a data rate control (hereinafter referred to as “DRC”) detected by a DRC signal detection unit 116 described later.
The communicable transmission rate of each communication terminal device is grasped based on the signal, the allocation of communication resources to each communication terminal device is determined, and the buffer 102 is instructed to output the downlink transmission data. Here, the DRC signal is a signal indicating a transmission rate at which the communication terminal device can receive with a desired quality.
Details of this DRC signal will be described later.

The allocating unit 101 also instructs the adaptive coding unit 103 on the coding system of downlink transmission data,
The adaptive modulation unit 104 is instructed of the downlink transmission data modulation method, and the adaptive spreading unit 105 is instructed of the spreading code by which the downlink transmission data is to be multiplied.

The buffer 102 holds downlink transmission data, and adaptively encodes the downlink transmission data for a predetermined communication terminal device according to an instruction from the allocating unit 101.
Output to. The adaptive encoding unit 103 includes an allocation unit 101.
In accordance with the instruction of 1., the transmission data from the buffer 102 is encoded, and the encoded transmission data is adaptively modulated by the adaptive modulation unit 10.
Output to 4.

[0021] Adaptive modulation section 104 modulates the transmission data coded by adaptive coding section 103 according to an 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 an instruction from allocation section 101, and outputs the spread transmission data to multiplexing section 108.

On the other hand, modulating 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 it to multiplexing section 108.

Multiplexing section 108 time-multiplexes the spread downlink transmission data and the spread pilot signal to generate a transmission 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 the amplified transmission signal is transmitted by the transmission RF unit 110. Output to.

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

RF receiving section 113 converts the frequency of the received signal from duplexer 111 to baseband, and outputs the received signal converted to baseband to despreading section 114.
The despreading unit 114 despreads the received signal converted into the baseband signal and outputs it to the demodulation unit 115. Demodulation unit 11
Reference numeral 5 demodulates the reception signal despread by the despreading unit 114 to generate a demodulation signal, and outputs the generated demodulation signal to the DRC signal detection unit 116 and the power margin information detection unit 117.

DRC detecting section 116 detects a DRC signal from the demodulated signal generated by demodulating section 115 and outputs the detected DRC signal to allocating section 101. The power margin information detection unit 117 detects 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.

Power setting section 118 sets the transmission power value of the transmission signal of each communication terminal apparatus using the power margin information from power margin information detecting section 117, and outputs the set transmission power value to power control section 109. To do.

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

Further, the required modulation scheme determination unit 201 instructs the adaptive despreading unit 210 to perform a spreading code to multiply the received signal based on the determined transmission rate, and the adaptive demodulation unit 211 receives the received signal. And the adaptive decoding unit 212 is instructed to decode the received signal.

The margin calculation unit 202 uses a CIR which will be described later.
The power margin is calculated using the CIR measured by the measurement unit 214 and the transmission rate determined by the required modulation scheme determination unit 201, and information regarding the calculated power margin, that is, power margin information is output to the combining unit 215. The DRC signal creation unit 203 creates a DRC signal indicating the transmission rate calculated by the requested modulation scheme determination unit 201 and outputs the DRC signal to the synthesis unit 215.

The combining unit 215 is a DRC signal creating unit 203.
Generates a combined signal by combining the DRC signal from the power calculation unit 202 and the power margin information from the margin calculation unit 202.
The generated combined signal is output to the modulator 204.

Modulation section 204 modulates the combined signal from combining section 215 and outputs it to spreading section 205. Diffusion unit 205
Outputs the synthesized signal modulated by the modulation unit 204 to the transmission RF unit 206. The transmission RF unit 206 frequency-converts the combined signal spread by the spreading unit 205 into a radio frequency and outputs the radio frequency to the duplexer 207.

The duplexer 207 transmits the combined signal whose frequency is converted by the transmission RF section 206 to the base station apparatus via the antenna 208. Further, duplexer 207 outputs the signal (reception signal) transmitted from the base station apparatus and received by antenna 208 to reception RF section 209.

RF receiving 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 section 210 despreads the received signal from the received RF section 209 in accordance with the instruction of the required modulation method determining section 201, and extracts components other than the pilot signal (components corresponding to data) in the received signal. The extracted component is output to the adaptive demodulation unit 211. Adaptive demodulator 21
1 demodulates the component extracted by the adaptive despreading unit 210 according to the instruction of the required modulation scheme determining unit 201 to generate a demodulated signal. The adaptive decoding unit 212 extracts the received data by decoding the demodulated signal from the adaptive demodulation unit 211 according to the instruction of the required modulation scheme determination unit 201.

On the other hand, the despreading unit 213 has a reception RF unit 20.
The received signal from 9 is despread to extract the pilot signal component in the received signal, and the extracted pilot signal component is output to CIR measurement section 214. CIR measurement unit 2
14 measures the CIR using the component of the pilot signal from despreading section 213 and outputs the measured CIR to requested modulation scheme determining section 201 and margin calculating section 202.

Next, the operation 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, the pilot signal is modulated by the modulation unit 106 in the base station apparatus and spread by the spreading unit 10.
7 spreads and outputs to the multiplexing unit 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 into a radio frequency by the transmission RF unit 110, and is transmitted from the antenna 112 to each communication terminal device via the duplexer 111. This pilot signal is transmitted to each communication terminal device via the control channel.

The pilot signal (control channel signal) transmitted by the base station device is the antenna 2 of the communication terminal device.
08. A signal (reception signal) received by the antenna 208 is received by the reception RF unit 2 via the duplexer 207.
It is output to 09. The reception signal from the duplexer 207 is frequency-converted into the baseband by the reception RF unit 209,
The despreading unit 213 despreads the data. By this means, despreading section 213 extracts the pilot signal from the received signal. The extracted pilot signal is output to CIR measurement section 214.

In the CIR measuring unit 214, the despreading unit 213
The CIR is measured based on the pilot signal output by. The measured CIR is used as the required modulation method determination unit 2
01 and the margin calculation unit 202.

The required modulation scheme determination unit 201 determines the transmission rate at which the communication terminal device can receive the desired quality based on the CIR measured by the CIR measurement unit 214. A method of determining the transmission rate by the required modulation method determining unit 201 will be described with reference to FIG. FIG. 3 is a schematic diagram showing a method of determining the transmission rate by the required modulation scheme determination unit 201 of the communication terminal apparatus including the communication apparatus according to the first embodiment of the present invention.

The required modulation scheme determination unit 201, based on the CIR (reception quality) measured by the CIR measurement unit 214, the characteristic (error rate characteristic) of the received signal of this communication terminal apparatus.
Satisfies the desired quality, and the transmission rate required of the base station apparatus is determined so that the data transmission efficiency becomes the best.

Specifically, for example, the CIR measuring unit 214
When the CIR measured by the above is a value (reception CIR 301) as shown in FIG. 3, the characteristics of the reception signal of the communication terminal device are of desired quality (here, the error rate is 10 ⁻³ ). .) Is one of the transmission rate corresponding to QPSK, the transmission rate corresponding to 16QAM, and the transmission rate corresponding to 64QAM. Among such transmission rates, the transmission rate that maximizes the data transmission efficiency is the transmission rate corresponding to 64QAM. As a result, the CIR as shown in FIG.
Is measured, the transmission rate corresponding to 64QAM is determined as the transmission rate required of the base station apparatus.

As described above, the required modulation method determination unit 20
The transmission rate determined by 1 is the margin calculation unit 20.
2 and the DRC signal generation unit 203. After the transmission rate is determined, the required modulation method determination unit 201
For adaptive despreading section 210, adaptive demodulating section 211, and adaptive decoding section 212, a signal instructing a spreading code to be multiplied by the received signal, a signal instructing a demodulation method of the received signal, and decoding of the received signal are respectively performed. A signal indicating the conversion method is output.

The margin calculating section 202 calculates the power margin using the CIR measured by the CIR measuring section 214 and the transmission rate determined by the required modulation scheme determining section 201. That is, the margin calculation unit 2
In 02, first, the transmission rate determined by the required modulation scheme determination unit 201 is applied, and the reception quality (hereinafter referred to as “first reception quality”) when the base station transmits at the requested transmission rate, and this. In this case, the difference between the characteristic of the received signal and the minimum required reception quality (hereinafter referred to as “second reception quality”) to satisfy the desired quality is calculated. Then, a power margin is calculated as a power value corresponding to the calculated difference. The power margin is the transmission power value (normally transmitted transmission power) in the base station apparatus required for the communication terminal apparatus to obtain the first reception quality, and the transmission power value for the communication terminal apparatus to obtain the second reception quality. This corresponds to the difference from the required transmission power value in the base station device.

Specifically, referring to FIG. 3, first, the CIR vs. BER of the transmission rate (transmission rate corresponding to 64QAM) determined by the required modulation method determination section 201.
The second reception quality (CIR 302) that is the minimum necessary for the characteristics of the received signal to satisfy the desired quality (BER = 10 ⁻³ ) is calculated according to the curve representing the characteristics. Furthermore, the first reception quality (reception CIR 301) and the second reception quality (CIR 30
After the difference with 2) is calculated, the power value corresponding to the calculated difference is calculated as the power margin 303.

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 transmission power value in the base station apparatus to obtain the second reception quality You may make it calculate the difference of each transmission power value, after calculating each required transmission power value in a base station apparatus. The information regarding the power margin calculated as described above is output to the combining unit 215 as the power margin information.

In the DRC signal creating section 203, the DR indicating the transmission rate calculated by the required modulation method determining section 201 is displayed.
A C signal is created. The created DRC signal is used by the synthesizing unit 2
It is output to 15.

In the combining unit 215, the DRC signal creating unit 20
The DRC signal from 3 and the power margin information from the margin calculation unit 202 are combined to generate a combined signal. The generated combined signal is output to the modulator 204.

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

The signal transmitted by the communication terminal apparatus is received by the antenna 112 of the base station apparatus. The signal (received signal) received by the antenna 112 is used by the duplexer 1
It is output to the reception RF unit 113 via 11. Shared device 1
The reception signal from 11 is frequency-converted into a baseband by the reception RF unit 113, despread by the despreading unit 114, and demodulated by the demodulation unit 115. As a result, the demodulation unit 115 generates a demodulation signal. The generated demodulated signal is output to the DRC signal detection unit 116 and the power margin information detection unit 117.

The power margin information detector 117 detects power margin information from the demodulated signal from the demodulator 115. The detected power margin information is used by the power setting unit 11
8 is output.

The power setting section 118 recognizes the power margin of each communication terminal device based on the detected power margin information. Further, the power setting unit 118 sets the transmission power value of the transmission signal of each communication terminal device in consideration of the recognized power margin of each communication terminal device. In particular,
In the conventional communication using HDR, the transmission power of the transmission signal of each communication terminal device is always a predetermined transmission power value (constant).
However, in the present embodiment, a value obtained by subtracting the power margin of the communication terminal device from the predetermined transmission power value is set as the transmission power value of the transmission signal of this communication terminal device. 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 device. The transmission power value of the transmission signal of each communication terminal device set by the power setting unit 118 in this way is output to the power control unit 109.

On the other hand, the DRC signal detector 116 detects the DRC signal from the demodulated signal generated by the demodulator 115. The detected DRC signal is assigned to the allocation unit 101.
Is output to.

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

The downlink transmission data output from the buffer 102 is coded by the adaptive coding unit 103 by a coding method that can be received by the communication terminal apparatus, and by the adaptive modulation unit 104 by a modulation method that can be received by the communication terminal apparatus. The signal is modulated, spread by the adaptive spreading unit 105 with a spreading code that can be received by the communication terminal apparatus, and output to the multiplexing unit 108. Multiplexing part 10
In 8, the transmission signal is generated 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 into a radio frequency by the transmission RF unit 110, and the antenna 11 is transmitted via the duplexer 111.
2 is transmitted to each communication terminal device.

The signal transmitted by the base station apparatus is received by the antenna 208 of the communication terminal apparatus. The signal (received signal) received by the antenna 208 is shared by the duplexer 2
It is output to the reception RF unit 209 via 07. Shared device 2
The reception signal from 07 is frequency-converted into a baseband by the reception RF unit 209 and despread by the adaptive despreading unit 210. As a result, adaptive despreading section 210 extracts components (components corresponding to data) other than pilot signals in the received signal. The components other than the extracted pilot signal are demodulated by the adaptive demodulation unit 211 and decoded by the adaptive decoding unit 212. As a result, the received data is taken out.

Next, the effect of the communication device according to the present embodiment will be described with reference to FIG. Figure 4
FIG. 3 is a schematic diagram showing a manner in which a communication terminal device including the communication device according to the first embodiment of the present invention and a base station device perform communication using HDR.

In FIG. 4, base station apparatus 401 corresponds to the base station apparatus shown in FIG. 1, and communication terminal apparatuses 402 to 40.
4 and the communication terminal devices 410 to 412 correspond to the communication terminal devices shown in FIG. The base station device 401 is currently
It is assumed that communication is performed with communication terminal devices 402 to 404 existing in a cell area 405 covered by this base station device 401. The communication terminal devices 410 to 412 are
Although it exists within the range of the cell area 405, it is assumed that it is communicating with a base station device other than the base station device 401. Since the cell areas are usually designed to overlap with each other, the communication terminal devices 410 to 412 exist in the overlapping area of the cell area of the base station device 401 and the cell areas of base stations other than the base station device 401. Will be.

As described above, the base station device 401 performs scheduling based on the communication mode selected by the communication terminal devices 402 to 404, sets a transmission rate for each communication terminal device, and communicates through the control channel. Signals indicating allocation of communication resources are broadcast to 402 to 404. Further, the base station device 401 transmits data via the data channel only to the corresponding communication terminal device at the allotted time.

Here, as an example, attention is paid to the time when 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 the reception quality in all communication terminal devices existing in the cell area 405 is sufficiently good. I shall. In this case, as described above, the communication terminal devices 410 to 41
The communication terminal device receiving the data from the other base station device among the two is the base station device 401 to the communication terminal device 402.
Will be interfered by the signal transmitted to.

However, in the present embodiment, base station apparatus 401 does not communicate with communication terminal apparatus 402 in cell area 4.
No data is transmitted using a transmission power value such that the reception quality in all communication terminal devices existing in 05 is sufficiently good. 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 required for the characteristics of the received signal of the communication terminal device 402 to satisfy the desired quality. Terminal device 4
The data is transmitted to 02. This minimum required transmission power value corresponds to the minimum required transmission power value for the reception quality of the communication terminal device existing in area 406 to satisfy the desired quality.

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

In parallel with the above-mentioned communication, the base station device 401 and the communication terminal devices 402 to 404 use a band different from the frequency band used for HDR and use the normal C
It goes without saying that the DMA communication is performed.

Further, in the present embodiment, the base station apparatus is
The case where data is transmitted to only one communication terminal device at the same time has been described, but the present invention is also applied to the case where the base station device transmits data to a plurality of communication terminal devices at the same time. It is possible. In this case, delayed waves of signals transmitted from the base station device to the plurality of communication terminal devices can suppress the possibility of interfering with each other, so that the communication quality of the plurality of communication terminal devices is kept good. be able to.

As described above, in the present embodiment, H
At the time of communication using DR, the base station apparatus uses the transmission power value such that the reception quality of all the communication terminal apparatuses existing in the cell covered by this base station apparatus is sufficiently good. Instead of transmitting data to the communication terminal device, data is transmitted to this communication terminal device using the minimum transmission power value required for the characteristics of the received signal of the communication terminal device to satisfy the desired quality. Thus, while maintaining the quality of the received signal in the communication terminal apparatus at a desired quality, communication using the HDR is performed with another base station apparatus among the communication terminal apparatuses existing in the area covered by the base station apparatus. It is possible to suppress the interference given to the communication terminal device.

In the present embodiment, the communication terminal apparatus determines the transmission rate and the power margin based on the measured reception quality, notifies the base station apparatus of the determined transmission rate and the power margin, and then the base station apparatus ,, by using the notified transmission rate and power margin, an example of setting the transmission power value of the transmission signal of this communication terminal device has been described, but notifies the base station device of the reception quality measured by the communication terminal device, The base station apparatus may set the transmission power value of the transmission signal of this communication terminal apparatus using the transmission rate and the power margin determined based on the notified reception quality. Thereby, the scale and power consumption of the communication terminal device can be suppressed.

The power margin may be transmitted from the communication terminal device only when the DRC having the highest 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 that it is located near the base station. Therefore, the transmission power of the base station can be significantly reduced, and the effect of avoiding interference is great.

(Embodiment 2) In this embodiment, a case will be explained in which even reduction of transmission power is taken into consideration when DRC is selected in a communication terminal apparatus. The present embodiment will be described below.

First, the configuration of the communication terminal apparatus according to this embodiment will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the communication terminal device according to the second exemplary embodiment of the present invention. The first embodiment shown in FIG.
About the same structure as (FIG. 2), the same code | symbol as what is in FIG. 2 is attached | subjected, and detailed description is abbreviate | omitted.

In FIG. 5, the DRC signal generation section 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. Also, DRC
The signal creation unit 501 converts the created DRC signal into the modulation unit 50.
Output to 2. The details of the DRC signal in this embodiment will be described later. Modulation section 502 modulates the DRC signal from DRC signal creation section 501 to spread section 20.
Output to 5.

Next, the configuration of the base station apparatus according to this embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the base station apparatus according to Embodiment 2 of the present invention. In addition, about the structure similar to Embodiment 1 (FIG. 1) in FIG. 6, the same code | symbol as what is in FIG. 1 is attached | subjected, and detailed description is abbreviate | omitted.

In FIG. 6, the power setting unit 601 is
The transmission power value of the transmission signal of each communication terminal device is set using the DRC signal detected by the C signal detection unit 116,
The set transmission power value is output to power control section 602.

The power control section 602 adjusts the adaptive spreading section 1 so that the transmission power value set by the power setting section 601 is reached.
The transmission data spread by 05 is amplified, and the amplified transmission data is output to the multiplexing unit 604.

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

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

Next, the communication terminal device shown in FIG.
The operation performed with the base station apparatus shown in FIG. Detailed description of the same operations as those in the first embodiment will be omitted, and only operations different from those in the first embodiment will be described.

In FIG. 5, the required modulation method determination unit 201
Then, as described in the first embodiment, the CIR measuring unit 2
Based on the CIR measured by 14, the transmission rate at which the communication terminal device can receive the desired quality is determined.
The transmission rate determined by the required modulation method determination unit 201 is the margin calculation unit 202 and the DRC signal generation unit 50.
It is output to 1.

In the margin calculation unit 202, the first embodiment
As described above, the power margin is calculated 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 creation unit 501 as power margin information.

In the DRC signal creating section 501, the transmission rate decided by the required modulation scheme deciding section 201, and
A DRC signal is created using 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 the 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. The DRC signal is uniquely determined based on the power margin information from

Here, the DRC signal in the first embodiment is "indicates the transmission rate at which the communication terminal apparatus can receive the desired quality", whereas the DRC signal in the present embodiment is "Transmission rate at which the communication terminal apparatus can receive with desired quality, and power margin when this transmission rate is selected (this power margin is the same as that in the first embodiment)" are shown.

A specific example of the DRC table used by the DRC signal generator 501 will be described with reference to FIG. FIG. 7 is a schematic diagram showing an example of a DRC table used by the communication terminal device according to the second exemplary 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 decided by the required modulation scheme deciding section 201, and the power margin information (0, 5, 10, 15 [dB], etc.), the DRC signal (1
6) are associated.

For example, the required modulation method determination unit 201 selects the transmission rate corresponding to 16QAM, and the margin calculation unit 202 calculates the power margin 5 [dB] (even if the transmission power is lowered by 5 [dB]). , The DRC signal whose signal content is “4” is determined. The DRC signal created by the DRC signal creation unit 501 in this way is transmitted to the modulation unit 5
After being modulated by 02, it is output to spreading section 205.

In FIG. 6, the DRC signal detected by DRC signal detection section 116 is output to allocation section 101 and power setting section 601. The allocation unit 10
In 1, the processing as described in the first embodiment is performed.

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 detecting section 116. Specifically, the power setting unit 601 uses the DRC table used by the communication terminal apparatus shown in FIG.
The power margin corresponding to the DRC signal from 16 is recognized. Further, a value obtained by subtracting the power margin from the predetermined transmission power value is set as the transmission power value of the transmission signal of the communication terminal device.

For example, when the DRC signal of a certain communication terminal device is "4", the power setting unit 601 requests that this communication terminal device lower the transmission power value by 5 [dB]. Is recognized and the transmission power value of the communication terminal device 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 the power control unit 602.

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

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

The transmission data amplified by power control section 602 and the pilot signal amplified by power control section 603 are multiplexed by multiplexing section 604. This allows
Multiple signals are generated. The generated multiple signal is transmitted R
It is output to the F 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 the present embodiment, the communication terminal apparatus individually transmits the information indicating the transmission rate (modulation method) and the information indicating the power margin to the base station apparatus (Embodiment 1) ), The communication terminal apparatus transmits information indicating the combination of the transmission rate (modulation method) and the power margin to the base station apparatus. By this means, it is possible to reduce the amount of information (information regarding the transmission rate and the transmission power value) transmitted from the communication terminal device to the base station device, that is, the amount of information in the wireless channel.

For example, focusing on the amount of information required to transmit the power margin, in the first embodiment, if the power margin to be handled is a two-digit value (0 to 99 [dB]), the power margin alone has at least 7 bits. In contrast to the need for the amount of information, in the second embodiment, the combination of the transmission rate and the power margin is indicated by only the amount of information of 4 bits.
Six types of information can be transmitted.

Further, 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) while keeping the transmission power value substantially constant. As a result, the communication terminal apparatus can accurately measure the communication quality, and thus can accurately perform DRC selection (selection of modulation scheme and power margin).

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

In the embodiment of the present invention, the case where the DRC table in which the combination of the modulation method and the power margin is preset is used is described. However, the contents of this DRC table (for example, the power at the time of 16QAM transmission) If the reduction amount is 5 [dB], 10 [dB], etc.), the base station device may notify the communication terminal device in advance by a broadcast channel or the like before communication is performed.

Further, even during communication, it is possible to select the optimum power reduction amount by adaptively changing the DRC table contents for each communication terminal device according to various conditions such as communication quality. Become.

Further, in the present embodiment, the communication terminal device indicates the combination of the transmission rate and the power margin D.
The case of transmitting the RC signal has been described, but the communication terminal device calculates the transmission power value in the base station device based on the power margin, and transmits the DRC signal indicating the combination of the transmission rate and the calculated transmission power value. However, the base station device may set the transmission power value using the transmission power value in the DRC signal.

(Embodiment 3) In the present embodiment, when the communication of the transmission data to the communication terminal apparatus having good communication quality becomes dominant in the downlink (data channel) of the base station apparatus, A case where the transmission power of signals and transmission data for all communication terminal devices is reduced will be described.

For a communication terminal device having good communication quality, that is, a communication terminal device existing near the base station device (for example, a communication terminal device reporting the DRC signals 4 to 6 in FIG. 7 to the base station device). When the communication of the transmission data is dominant in the downlink in the cell of the base station device, the downlink is a communication terminal device existing at the end of this cell (a communication terminal device existing in a position far from the base station device). ) Is considered to be rarely assigned to. Even in such a case, in the conventional method, the base station device transmits the pilot signal and the transmission data by using constant power so as to reach all the communication terminal devices in the cell.

However, in the above case, first, focusing on the transmission data, the base station device may transmit the transmission data to the communication terminal device located at a position far from the own station. However, the transmission data is transmitted to the communication terminal device existing in the position close to the own station by using the constant power so that the reception quality of the communication terminal device becomes good. That is, the base station device transmits the transmission data to the communication terminal device by using the transmission power that is higher than necessary.

As a result, the base station device gives a large interference to the communication terminal device in the cell covered by another base station device. Further, when the base station device performs HDR communication with a plurality of communication terminal devices at the same time, it gives a large interference to the plurality of communication terminal devices existing in the cell covered by the base station device.

Secondly, in the above case, paying attention to the pilot signal, the base station apparatus transmits the pilot signal by using the electric power that reaches all the communication terminal apparatuses existing in the cell. . Here, the base station device is unlikely to transmit the transmission data to the communication terminal device that is located far from the own station. Therefore, if the communication of the transmission data to the communication terminal device having good communication quality is limited only to the situation in which the downlink of the base station device becomes dominant, the communication of the base station device existing at a position far from the own station. The need to send pilot signals to the terminal equipment is low. Therefore, it can be said that the base station device is transmitting the pilot signal by using an excessive transmission power.

Furthermore, the fact that the base station apparatus transmits the pilot signal using the transmission power that is higher than necessary means that it interferes with the communication terminal apparatus existing in the cell of another base station apparatus. .

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

That is, the base station apparatus reduces the cell radius (since each communication terminal apparatus measures the communication quality using the CIR of the pilot signal, it is not possible for the base station apparatus to reduce the transmission power of the pilot signal. It is equivalent to the station device reducing the size of the cell). In other words, the base station apparatus concentrates on the communication terminal apparatus selected as the transmission destination of the transmission data, using a power smaller than the normal transmission power, with respect to the communication terminal apparatus existing in a position close to the own station. For the communication terminal device that transmits the transmission data and exists at a position far from the own station, the communication terminal device is accommodated in the cell of another base station device or the transmission data of the transmission data to the communication terminal device that exists near the own station is received. The transmission data is transmitted after the transmission is completed.

By this means, the base station apparatus can intensively perform communication of transmission data to a communication terminal apparatus having good communication quality while suppressing interference with other cells.

When the amount of communication of the transmission data to the communication terminal device having good communication quality becomes small, the base station device restores the transmission power of the transmission data and the transmission power of the pilot signal (based on the size of the cell). So that the transmitted data and pilot signals 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 the transmission data transmission destinations are communication terminal apparatuses that are located far from the own station, and the transmission data and pilot Restores the signal transmission power.

By controlling the transmission power as described above, all base station apparatuses can reduce interference power with other base station apparatuses. This allows
Since all base station devices can reduce power consumption, it is possible to utilize radio resources more effectively.

Next, the configuration of the base station apparatus described above will be explained with reference to FIG. FIG. 8 is a block diagram showing the configuration of the base station apparatus according to Embodiment 3 of the present invention. Here, the base station device shown in FIG.
A case of performing communication with the communication terminal device shown in FIG. 5 using the DRC table shown in FIG. 7 will be described as an example. However, as the communication terminal device communicating with the base station device shown in FIG.
Any configuration may be used as long as it has a configuration for reporting the C signal to the base station device. It should be noted that the same components in FIG. 8 as those in FIG. 1 or 6 are denoted by the same reference numerals as those in FIG. 1 or 6, and detailed description thereof will be omitted.

As in Embodiment 1, allocation section 101 determines allocation of communication resources to each communication terminal apparatus based on the DRC signal (transmission to a communication terminal apparatus that has reported a high DRC signal). Prioritize data transmission).

Downlink quality estimating section 801 uses the DRC signal from DRC signal detecting section 116 to establish a communication terminal apparatus located near the own station, that is, a communication terminal apparatus having a good communication quality (of the pilot signal). It recognizes how many communication terminal devices have a CIR larger than a predetermined value, generates information indicating the transmission power based on the recognition result, and outputs the information to the power setting unit 802.

Power setting section 802 sets the transmission power value of the pilot signal and the transmission data based on the information from downlink quality estimation section 801, 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 explained with reference to FIG. 9 in addition to FIG. FIG. 9 is a flowchart showing the operation of the base station apparatus according to Embodiment 3 of the present invention. Note that operations similar to those in Embodiment 1 or Embodiment 2 of the present 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 communication within the cell of the own station. When the ratio of the communication terminal devices that have reported the DRC value 6 in all the communication terminal devices that perform the above (hereinafter simply referred to as “the number or ratio of the communication terminal devices having the DRC value 6”) exceeds a predetermined value, ST90
As shown in FIG. 2, 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 contrary, when the number or the ratio of the communication terminal devices having the DRC value 6 is less than or equal to the predetermined value, the process proceeds to ST903.

In ST903, if the number or ratio of the communication terminal devices having the DRC value of 5 or more exceeds the predetermined value, the ST
As shown in 904, the transmission power value is set to 10 [d
B] Information instructing the lowering is output to the power setting unit 802. On the contrary, if the number or ratio of the communication terminal devices having the DRC value of 5 or more is less than or equal to the predetermined value, the process proceeds to ST90
Go to 5.

In ST905, if the number or ratio of the communication terminal devices having the DRC value of 4 or more exceeds the predetermined value, the ST
As shown in 906, the transmission power value is 5 [dB] higher than usual.
Information instructing the lowering is output to the power setting unit 802. On the contrary, when the number or ratio of the communication terminal devices having the DRC value of 4 or more is less than or equal to the predetermined value, the process proceeds to ST907.

[0118] In ST907, it is recognized that the communication of the transmission data to the communication terminal apparatus having the good communication quality is not dominant in the downlink of the base station apparatus, and the transmission power value is made normal. Is output to the power setting unit 802.

Thereafter, power setting section 802 sets the transmission power values of the pilot signal and transmission data based on the information instructed by downlink quality estimating section 801. That is, based on the information from the downlink quality estimation unit 801, the normal transmission power value is changed to 15 [dB] (ST
902), 10 [dB] (ST904), 5 [dB]
By subtracting either (ST906) or 0 [dB] (ST907), the transmission power value of the pilot signal and the transmission data is set. It goes without saying that the normal transmission power value here corresponds to a transmission power value that allows all communication terminal devices existing in the cell of the own station to receive with sufficient quality.

A value subtracted from the normal transmission power value is set according to the magnitude of the DRC value (ST902, ST904, ST906 and ST90 in FIG. 9).
7) considers that the optimum value of the transmission power value for this communication terminal device differs depending on the magnitude of the DRC value reported by the communication terminal device, that is, the distance of the communication terminal device from its own station. Because. By this means, it is possible to reliably maintain good reception quality in the communication terminal device that receives the transmission data.

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

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

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

As described above, in the present embodiment, the communication quality is good (there is a position close to the base station device).
According to the ratio of the communication of the transmission data to the communication terminal device in the downlink, that is, in accordance with the ratio of the communication to the transmission data to the communication terminal device with good communication quality for the downlink, the base station device, By determining the transmission power value of the pilot signal and the transmission data for all communication terminal devices, interference with the communication terminal devices existing in the cell of the own station and the cells of other stations is suppressed, and the total downlink throughput (communication terminal The total amount of transmission data transmitted to the device) can be improved.

[0125] Specifically, when the ratio of communication of transmission data to a communication terminal device having good communication quality to the downlink is large, the distance of the communication terminal device having good communication quality to its own station is set. Based on the same, by uniformly lowering the transmission power value of the transmission data for the pilot signal and all communication terminal devices, while maintaining good reception quality in the communication terminal device having good communication quality, the cell of the own station and other stations It is possible to suppress interference with communication terminal devices existing in the cell.

On the contrary, when the ratio of the transmission data communication to the communication terminal device having good communication quality to the downlink is small, the transmission power values of the pilot signal and the transmission data to all the communication terminal devices are kept low. Then, since the reception quality in many communication terminal devices located far from the base station device deteriorates, the total downlink throughput decreases, so the transmission power of the transmission data for the pilot signal and all communication terminal devices is reduced. Set the value to a normal value. As a result, the total downlink throughput can be increased, that is, the transmission efficiency can be improved.

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

In the above-mentioned third embodiment, the transmission power values of the pilot signal and the transmission data are lowered according to the ratio of the transmission data communication to the communication terminal apparatus having good communication quality to the downlink. However, when the transmission power value of the transmission data is reduced, a large number of packets that are not correctly received by the communication terminal device may occur, and the total downlink throughput may be reduced. As a result, inefficient transmission is performed.

Therefore, in this embodiment, it is monitored whether or not the total downlink throughput is maintained, and if the downlink total throughput drops after the transmission power value of the transmission data is lowered, The transmission power value of the transmission data should be close to the normal value.

The configuration of the base station apparatus according to this embodiment will be described below with reference to FIG. Figure 10
FIG. 6 is a block diagram showing a configuration of a base station device according to Embodiment 4 of the present invention. The third embodiment shown in FIG.
About the same structure as (FIG. 8), the same code | symbol as what is in FIG. 8 is attached | subjected, and detailed description is abbreviate | omitted.

In FIG. 10, allocation section 1001 has the same configuration as allocation section 101 in the third embodiment, except for the following points. That is, the allocation unit 1
001 outputs, to the downlink quality estimation unit 1002, the result of communication resource allocation to each communication terminal device determined based on the DRC signal (which communication terminal device is transmitted at what transmission rate). To do.

Downlink quality estimating section 1002 has the following characteristics except for the following points.
It has the same configuration as that of No. 1. That is, downlink quality estimation section 1002 monitors the change in the total throughput of the downlink using the allocation result from allocation section 1001, and based on the recognition result and the change in this total throughput described in the third embodiment. The power setting unit 802 generates information indicating the transmission power and outputs the information to the power setting unit 802.

Next, the operation of the base station apparatus having the above configuration will be explained with reference to FIG. 11 in addition to FIG. FIG. 11 is a flowchart showing the operation of the base station apparatus according to Embodiment 4 of the present invention. Detailed description of the same operation in FIG. 11 as that in FIG. 9 is omitted.

After the transmission power value is lowered by 15 [dB] from the normal level in ST902, downlink channel quality estimation section 1002 assigns allocation section 10 as shown in ST1101.
The total downlink throughput is monitored based on the allocation result from 01, and it is determined whether the total throughput is lower than before the transmission power was reduced. If the total throughput has not decreased, the process proceeds to ST described above.
The process moves to 901. If the total throughput has decreased, the process proceeds to ST904 described above.

Similarly, after the transmission power value is reduced by 10 [dB] from the normal level in ST904, ST1102 is set.
As shown in, the downlink quality estimation unit 1002 determines whether or not the total throughput is lower than that before the transmission power is reduced. If the total throughput has not decreased, the process proceeds to ST901 described above. If the total throughput is decreasing, the process proceeds to S described above.
Move to T906.

Similarly, in ST906, after the transmission power value is reduced by 5 [dB] from the normal value, in downlink quality estimating section 1002, the total throughput is lower than that before the transmission power is reduced, as shown in ST1103. Is determined. If the total throughput has not decreased, the process proceeds to ST901 described above. If the total throughput is decreasing, the processing is performed in ST described above.
Move to 907.

In this embodiment, when the total throughput after lowering the transmission power value cannot be maintained at the total throughput before lowering the transmission power value, the transmission power is gradually approached to the normal value. Although the case where the transmission power value is increased (the transmission power value is gradually increased) has been described, the transmission power value may be directly returned to the normal value.

As described above, according to the present embodiment, the transmission power value of the pilot signal and the transmission data is brought close to the normal value according to the change in the total throughput of the downlink, so that the transmission data is lowered. It is possible to prevent a decrease in the total downlink throughput due to the reduction. As a result, efficient transmission of transmission data can be realized.

(Embodiment 5) In the present embodiment, a base station apparatus is a communication terminal apparatus with good communication quality (close to itself) based on the number of communication terminal apparatuses that have reported a predetermined DRC signal. It is detected whether the communication of the transmission data to the communication terminal device existing in the position) is dominant in the downlink (that is, whether the downlink has excessive quality), and further based on the detection result. Then, the case of changing the transmission power of the pilot signal and the transmission data for all communication terminal apparatuses will be described.

In the third embodiment, whether transmission data communication to a communication terminal device having good communication quality is dominant in the downlink in the cell of the base station device is determined as the transmission data transmission destination. And the total number of communication terminals
The detection is performed using the ratio with 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 the transmission data is transmitted is small, the transmission power of the pilot signal and the transmission data to all the communication terminal devices is lowered because the above ratio exceeds the threshold value. When this happens, the total throughput may decrease.

Therefore, in the present embodiment, the predetermined DRC
Based on the number of communication terminal devices that have reported the signal, it is detected whether or not communication to the communication terminal device with good communication quality is dominant in the downlink, and based on this detection result, a pilot signal and The transmission power of transmission data for all communication terminal devices is changed.

Specifically, for example, when the number of communication terminal devices that have reported a predetermined DRC signal is greater than or equal to a threshold value, communication to communication terminal devices with good communication quality is dominant in the downlink. The transmission power is reduced to recognize that the transmission power has been exceeded and to prevent the transmission with an excessive transmission power. On the other hand, if the number of communication terminal devices that have reported the predetermined DRC signal is below the threshold, most of the communication terminal devices that are the destinations of the transmission data are located far from the own station. Is recognized and the transmission power is returned to the normal power value. By this means, it is possible to suppress interference with communication terminal devices existing in the cell of the own station and the cells of other stations and improve the total downlink throughput.

Next, the configurations of the communication terminal apparatus and base station apparatus according to the present embodiment will be described with reference to FIGS.
Will be explained. FIG. 12 is a block diagram showing the configuration of the communication terminal device according to the fifth embodiment of the present invention. FIG. 13 is a schematic diagram showing 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 the configuration of the base station apparatus according to Embodiment 5 of the present invention.

First, the configuration of the communication terminal device is shown in FIG.
Will be described with reference to. Note that the same components in FIG. 12 as those in FIG. 5 are designated by the same reference numerals as those in FIG. 5, and detailed description thereof will be omitted.

The DRC signal generating section 1201 uses the transmission rate determined by the required modulation method determining section 201 to perform D
Create an RC signal. Specifically, the DRC signal creation unit 1
201 is a DR indicating a DRC signal corresponding to the transmission rate
It has a C table (for example, the DRC table shown in FIG. 13) and creates a DRC signal corresponding to the transmission rate determined by the required modulation scheme determination unit 201. This DR
The C 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 addition, about the structure similar to FIG. 8 in FIG. 14, the same code | symbol as the thing in FIG. 8 is attached | subjected, and detailed description is abbreviate | omitted.

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

Next, the operations of the communication terminal apparatus and base station apparatus having the above configurations will be explained with reference to FIG. FIG. 15 is a flowchart showing the operation of the base station apparatus according to Embodiment 5 of the present invention. Note that the same operations as those in Embodiments 1 to 4 in this embodiment will be omitted.

In the communication terminal device shown in FIG. 12, DR
The C signal generation unit 1201 generates a DRC signal corresponding to the transmission rate determined by the requested modulation scheme determination unit 201 according to the DRC table shown in FIG. The generated DRC signal is output to the modulator 502.

The operation of the base station apparatus shown in FIG. 14 is as follows. That is, downlink quality estimation section 1401
Then, first, as shown in ST1501, the number of communication terminal apparatuses that have reported the DRC value 3 is recognized using the DRC signal from DRC signal detection section 116, and then the recognized number is compared with a threshold value. Is done.

As a result of this comparison, when the number of communication terminal devices that have reported the DRC value 3 is equal to or greater than the threshold value, the communication terminal device with good communication quality (the communication terminal device that has reported the DRC value 3) is selected. It is recognized that the communication of the transmission data of 1 is predominant in the downlink, and, as shown in ST1502, information for instructing to reduce the transmission power by 1 [dB] is generated. On the contrary, when the number of communication terminal devices reporting the DRC value 3 is less than the threshold value,
It is recognized that most of the communication terminal devices that are the destinations of the transmission data are communication terminal devices that are located far from the own station, and the process proceeds to ST1503.

In ST1503, it is determined whether or not the transmission power value at the present time is the normal transmission power value (maximum value). When the transmission power value at the present time is smaller than the normal transmission power value, as shown in ST1504, information instructing to increase the transmission power by 1 [dB] is generated. On the contrary, when the transmission power value at the present time is the normal transmission power value, information instructing not to change the transmission power is generated, and the process proceeds to ST1501.

As described above, the downlink quality estimation unit 14
The information generated by 01 is output to the power setting unit 802. In the power setting unit 802, the downlink quality estimation unit 1
The transmission power values of the pilot signal and the transmission data are set based on the information designated by 401.

As described above, in this embodiment, the communication quality is good (there is a position close to the base station apparatus).
According to the number of communication terminal devices, the base station device determines the transmission power value of the pilot signal and the transmission data to all the communication terminal devices, so that the communication terminals existing in the cell of the own station and the cells of other stations It is possible to suppress interference with the device and improve the total downlink throughput.

Specifically, when the number of communication terminal devices having good communication quality is equal to or greater than the threshold value, the transmission power values of the pilot signal and the transmission data to all the communication terminal devices are uniformly reduced to make the above communication. It is possible to suppress interference with communication terminal apparatuses existing in the cell of the own station and the cells of other stations while maintaining good reception quality in the communication terminal apparatus having good quality.

On the contrary, when the number of communication terminal devices having good communication quality is lower than the threshold value, if the transmission power values of the pilot signal and the transmission data for all the communication terminal devices are kept low, the position far from the base station device is reached. As the reception quality in many communication terminal devices existing in the above deteriorates, the total downlink throughput decreases, so the transmission power value of the pilot signal and the transmission data for all the communication terminal devices is set to the normal transmission power value. Get closer. This increases the total downlink throughput, that is,
The transmission efficiency can be improved.

Further, according to the present embodiment, when the total number of communication terminal devices to which the transmission data is transmitted is small, the transmission power is changed based on the number of communication terminal devices having good communication quality. As compared with the third embodiment, it is possible to suppress a decrease in the total downlink throughput.

In this embodiment, the case has been described as an example where the communication terminal apparatus reports the DRC signal designating only the modulation method to the base station apparatus. However, the present invention is not limited to this. It goes without saying that the present invention is also applicable to the case of reporting a DRC signal as described in the first to fourth embodiments.

Further, in the present embodiment, in order to prevent a decrease in the total throughput of the downlink due to the small number of the communication terminal devices that are the destinations of the transmission data, communication with good communication quality is performed. Based on the number of terminals
Although the case where the transmission power is changed has been described, similar to the third embodiment, based on the ratio between the number of communication terminal devices having good communication quality and the total number of communication terminal devices to which transmission data is transmitted, It goes without saying that it is also possible to change the transmission power.

(Embodiment 6) In the present embodiment, in the case where the transmission power value of the pilot signal and the transmission data is brought close to the normal transmission power value in accordance with the change in the total throughput in the downlink in Embodiment 5. Will be described.

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

Therefore, in the present embodiment, the fourth embodiment will be described.
Similarly, monitor whether the total downlink throughput is maintained, and if the downlink total throughput drops after lowering the transmission power value of the transmission data, set the transmission power value of the transmission data to the normal value. Try to get close to the value.

The configuration of the base station apparatus according to this embodiment will be described below with reference to FIG. 16
FIG. 9 is a block diagram showing a configuration of a base station device according to Embodiment 6 of the present invention. Note that the same components as those in FIGS. 10 and 14 in FIG. 16 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 16
01 has the same configuration as downlink quality estimating section 1401 in Embodiment 5 except for the following points. That is, downlink quality estimating section 1601 monitors the change in total throughput of the downlink using the allocation result from allocating section 1001, and based on the comparison result and the change in total throughput described in the fifth embodiment. And power generation unit 802 that generates information instructing the transmission power.
Output to. The configuration of the communication terminal device according to the present embodiment is similar to that of the fifth embodiment (FIG. 12), and detailed description thereof will be omitted.

Next, the operation of the base station apparatus having the above configuration will be further explained with reference to FIG. FIG. 17
[Fig. 8] is a flow chart showing an operation of a base station apparatus according to Embodiment 6 of the present invention. Note that detailed description of operations in FIG. 17 similar to those in FIG. 15 is omitted.

In ST1502, the transmission power value is 1 [d
B] After being lowered, as shown in ST1701, downlink quality estimating section 1601 monitors the total downlink throughput based on the allocation result from allocating section 1001, and compares the total throughput before the transmission power is lowered. Is determined. If the total throughput has not decreased, the process proceeds to ST1501 described above.
Move to. If the total throughput is decreasing,
The process moves to ST1504 described above.

In this embodiment, when the total throughput after lowering the transmission power value cannot be maintained at the total throughput before lowering the transmission power value, the transmission power is gradually approached to the normal value. Although the case where the transmission power value is increased (the transmission power value is gradually increased) has been described, the transmission power value may be directly returned to the normal value.

As described above, according to the present embodiment, the transmission data can be lowered by bringing the transmission power values of the pilot signal and the transmission data closer to the normal values according to the change in the total throughput of the downlink. It is possible to prevent a decrease in the total downlink throughput due to the reduction. As a result, efficient transmission of transmission data can be realized.

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

FIG. 18A is a schematic diagram conceptually showing 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 shows
It is a schematic diagram which shows notionally the 2nd example of distribution of the DRC value reported by the communication terminal device concerning Embodiment 7 of this invention. 18A and 18B, for each DRC value shown on the horizontal axis, the vertical axis shows the number of communication terminal devices that have reported the DRC value.

As shown in FIG. 18 (a), when the distribution of DRC values is extremely biased toward the higher side (the higher transmission rate), the downlink of the cell has excessive quality. Can be guessed. That is, the base station device is
Since the transmission is performed by using the transmission power more than necessary, it causes a great interference to the communication terminal devices existing in the cell of the own station and the cell of the other station.

Therefore, in such a case, by reducing the transmission power of the pilot signal and the transmission data,
As shown in FIG. 18 (b), the distribution of the DRC values should not be extremely biased to the higher side (that is, the communication of the transmission data to the communication terminal device with good communication quality should not be dominant in the downlink). ) Do. By this means, it is possible to suppress interference with communication terminal devices existing in the cell of its own station and the cells of other stations.

The configuration of the base station apparatus according to this embodiment will be explained below. The configuration of the base station apparatus according to this embodiment is the same as that shown in FIG. 14 except that the downlink quality estimation section has the following configuration.

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

Next, the operation of the base station apparatus according to this embodiment will be further explained with reference to FIG. Figure 1
FIG. 9 is a flowchart showing the operation of the base station apparatus according to Embodiment 7 of the present invention. The description of the same operation as that of the fifth embodiment in this embodiment will be omitted.

In the downlink quality estimation section, first, the average value and variance of 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 more than the threshold value. If the calculated average value is equal to or more than the threshold value, the process proceeds to ST1902, and if the calculated average value is less than the threshold value, the process is performed. Moves to ST1904.

In ST1902, it is determined whether the calculated variance of the DRC values is less than or equal to the threshold value. If the calculated variance is less than or equal to the threshold value, the process proceeds to ST1903.
If it is larger than the threshold, the process proceeds to ST1904.
Move to.

In ST1903, it is recognized that the distribution of DRC is extremely biased to the higher side because 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. Therefore, the transmission power is, for example, 1 [d
B] Information for instructing lowering is generated.

On the other hand, in ST1904, when the calculated average value is less than the threshold value or the calculated variance is greater than the threshold value, it is recognized that the distribution of DRC is not extremely biased to the higher side. It Further, it is determined whether or not the current transmission power value is the normal transmission power value (maximum value). If the current transmission power value is the normal transmission power value, the process proceeds to ST1901, and if it is less than the normal transmission power value, the process proceeds to ST1905. In ST1905, the transmission power is set to, for example, 1 [dB].
Information is generated to instruct the raising. The 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 the DRC values reported by the communication terminal apparatus, whether or not the downlink has excessive quality, that is, the communication with good communication quality is performed. Whether communication of transmission data to the terminal device is dominant in the downlink,
Can be reliably detected.

(Embodiment 8) In this embodiment, a case will be described in which, in Embodiment 7, the transmission power value is controlled according to the average value of DRC values and the magnitude of variance.

In the seventh embodiment, the distribution state of the DRC values is detected using the average value and the variance of the DRC values, and the distribution state of the detected DRC values is extremely biased toward the higher side. In this case, the transmission power is lowered by 1 [db], and when the DRC distribution is not extremely biased to the higher side, the transmission power is raised 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 side, in some cases, the DRC distribution is biased toward a higher DRC value, and in some cases, the DRC distribution is smaller than in the first case. There is also a second case where the DRC value is biased. The optimum reduction range of the transmission power value is different when the distribution state of the DRC is in the first case and when it is in the second case. That is, the optimum reduction range in the second case is
From the viewpoint of interference with communication terminal devices in other cells and total throughput, it is preferable that the reduction range is smaller than the optimum reduction range in the first case.

Similarly, even in a situation where the DRC distribution is biased to the lower side, in some cases the DRC distribution is biased to a lower DRC value, the DRC distribution is more biased than in the third case. There is also a fourth case, which is biased towards higher DRC values.
The optimum increase range of the transmission power value is different when the distribution state of the DRC is in the third case and when it is in the fourth case. That is, it is preferable that the optimum increase range in the third case is larger than the increase range in the fourth case from the viewpoint of interference with communication terminal devices in other cells and total throughput.

Therefore, in the present embodiment, the DRC
After determining which DRC value is extremely biased based on the distribution state of the DRC values detected using the average value and the variance of the values, control of the transmission power value according to the determination result (that is, , Control the increase or decrease width).

The configuration of the base station apparatus according to this embodiment will be described below. The configuration of the base station apparatus according to this embodiment is the same as that shown in FIG. 14 except that the downlink quality estimation section has the following configuration.

That is, the downlink channel quality estimation section uses the DRC.
An average value and variance of DRC values (in other words, reception quality of pilot signals in each communication terminal apparatus) are calculated using the DRC signal from the signal detection unit 116, and the distribution state of the DRC values (specifically Which DRC
Is there a bias in the values?). The downlink quality estimation unit generates information indicating the transmission power based on the distribution state determination result, and outputs the information to the power setting unit 802.

Next, the operation of the base station apparatus according to this embodiment will be described with reference to FIGS. 20 and 21. FIG. 20 is a schematic diagram showing an example of the relationship between the average and variance of DRC values and the transmission power value in the base station apparatus according to Embodiment 8 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. The detailed description of the same operation as that of the seventh embodiment in this embodiment will be omitted.

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

Specifically, in ST2101, it is determined whether or not the average value and variance of 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), the transmission power is set to 10 [d] in ST2102.
B] After the information for lowering is generated, the processing is ST210.
Return to 1. On the contrary, when the average value and the variance are not in the area 6, the process proceeds to ST2103.

In ST2103, it is determined whether or not the average value and variance of DRC values are in region 5. If the mean and variance are in region 5 (ie, the DRC values are biased lower than in region 6), then S
After the information to reduce the transmission power by 6 [dB] is generated in T2104, the process returns to ST2101. vice versa,
If the average value and variance are not in region 5, the process proceeds to ST.
The process proceeds to 2105.

In ST2105, it is determined whether or not the average value and variance of DRC values are in region 4. If the mean and variance are in region 4 (ie, the DRC values are biased lower than in region 5), then S
After the information to reduce the transmission power by 3 [dB] is generated in T2106, the process proceeds to ST2101. On the contrary, if the average value and the variance are not in the region 4, the process proceeds to ST2107.

In ST2107, it is determined whether or not the average value and variance of DRC values are in region 3. If the mean and variance are in region 3 (ie, which D
In the most preferable case where the RC value is not biased), no information is generated to instruct whether to increase or decrease the transmission power, and the process proceeds to ST2101. vice versa,
If the average value and variance are not in region 3, the process proceeds to ST.
Moving to 2108.

In ST2108, it is determined whether or not the average value and variance of DRC values are in region 2. If the mean and variance are in Region 2 (ie low DRC
(If the values are biased), it is determined in ST2109 whether the current transmission power value is the normal transmission power value. If the current transmission power value is the 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 the normal transmission power value, ST
After the information instructing to increase the transmission power by 3 [dB] is generated in 2110, the process returns to ST2101.
On the contrary, in ST2108, the average value and the variance are in the region 2
If not, the process moves to ST2111.

In ST2111, it is determined whether or not the average value and variance of DRC values are in region 1. If the mean and variance are in Region 1 (ie, the DRC values are biased lower than in Region 2), then S
At T2112, it is determined whether the current transmission power value is the normal transmission power value. When the current transmission power value is the normal transmission power value, the information indicating that the transmission power is changed is not generated, and the process proceeds to ST2101.
Return to. If the current transmission power value is not the normal transmission power value, the transmission power value is set to 6 [d
B] After the information for instructing to raise is generated, the processing is S
Transition to T2101.

As described above, in the present embodiment, D
After determining which DRC value is extremely biased using the average value and variance of the RC values, the transmission power is controlled based on the result of the determination, thereby interfering with communication terminal devices in other cells. Can be reduced and the total throughput can be improved at high speed and with high accuracy.

When all the base station apparatuses carry out the control described in the above-mentioned Embodiments 1 to 8, it is possible to reduce the area where the areas of the base station apparatuses overlap. Therefore, the throughput may decrease for a moment when the transmission power is lowered, but in the long term, the throughput of the entire system can be maximized. Moreover, the base station apparatus and the communication terminal apparatus described in Embodiments 1 to 8 above can be used in combination.

[0199]

As described above, according to the present invention,
To provide a communication terminal device that performs communication using HDR with another base station device, and a communication device that suppresses interference exerted on the communication terminal device that communicates using the HDR with itself at the same time. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a base station device including a communication device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a communication terminal device including the communication device according to the first exemplary embodiment of the present invention.

FIG. 3 is a schematic diagram showing a method of determining a transmission rate by a required modulation scheme determination unit of a communication terminal apparatus including the communication apparatus according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a state in which a communication terminal apparatus including the communication apparatus according to the first exemplary embodiment of the present invention and a base station apparatus perform communication using HDR.

FIG. 5 is a block diagram showing a configuration of a communication terminal device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a base station device according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram showing an example of a DRC table used by the communication terminal device according to the second exemplary embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a base station device according to a third embodiment of the present invention.

FIG. 9 is a flowchart showing an operation of the base station apparatus according to the third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a base station apparatus according to Embodiment 4 of the present invention.

FIG. 11 is a flowchart showing the operation of the base station apparatus according to Embodiment 4 of the present invention.

FIG. 12 is a block diagram showing a configuration of a communication terminal device according to a fifth embodiment of the present invention.

FIG. 13 is a schematic diagram showing an example of a DRC signal used by the communication terminal device 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 Embodiment 5 of the present invention.

FIG. 15 is a flowchart showing an operation of the base station device according to the fifth embodiment of the present invention.

FIG. 16 is a block diagram showing the configuration of a base station apparatus according to Embodiment 6 of the present invention.

FIG. 17 is a flowchart showing the operation of the base station apparatus according to Embodiment 6 of the present invention.

FIG. 18 (a) is a schematic diagram conceptually showing a first example of the distribution of DRC values reported by the communication terminal device according to the seventh embodiment of the present invention. (B) According to the seventh embodiment of the present invention The schematic diagram which shows notionally the 2nd example of distribution of DRC value reported by the communication terminal device.

FIG. 19 is a flowchart showing an operation of the base station apparatus according to Embodiment 7 of the present invention.

FIG. 20 is a schematic diagram showing an example of the relationship between the average and variance of DRC values and the transmission power value in the base station apparatus according to Embodiment 8 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.

FIG. 22 is a schematic diagram showing how communication is performed using conventional HDR.

[Explanation of symbols]

101, 1001 Allocation unit 102 Buffer 103 Adaptive coding 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 Requested modulation method determination unit 202 Margin calculation unit 203 DRC signal creation unit 213 Despreading unit 214 CIR measurement unit 801, 1002, 1401, 1601 Downlink channel quality estimation unit

Continued front page    (72) Inventor Takahisa Aoyama             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. (72) Inventor Toyoki Kami             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. (72) Inventor Osamu Kato             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. (72) Inventor Katsuhiko Hiramatsu             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. (72) Inventor Jun Sumasu             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. (72) Inventor Junichi Aizawa             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. (72) Inventor Toshiyuki Uehara             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             No. Panasonic Mobile Communicator             Within Chonz Co., Ltd. F term (reference) 5K022 EE02 EE14 EE21 EE31                 5K067 AA21 BB21 CC10 DD11 DD51                       EE02 EE10 GG08 HH22

Claims (2)

[Claims] 1. A transmission power control method for a downlink signal transmitted using any one of the modulation schemes determined from a plurality of modulation schemes having different modulation multi-level numbers, other than the modulation scheme having the maximum modulation multi-level number. In this modulation method, with the transmission power kept constant, the better the downlink quality, the larger the modulation multi-value number.In the modulation method with the maximum modulation multi-value number, the modulation method is fixed and The transmission power control method is characterized in that the transmission power is reduced as the value is better. 2. A downlink signal transmission control method, wherein when the downlink quality is worse than a predetermined value, the first control is performed to change the modulation multi-value number while keeping the transmission power constant. When the quality is better than a predetermined value, a second control for changing the transmission power is performed while the modulation method is fixed, and the transmission control method is characterized.