JP2001345757A - Transmission power control method and device, and mobile communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unnecessary increase of transmission power when the state of a circuit is deteriorated and transmission power control information from a base station is erroneously recognized to be a command for increasing transmission power on the mobile communication terminal side. SOLUTION: In this transmission power control device of a mobile communication, radio waves are transmitted to and received from the radio wave base station, and the transmission power is adjusted on the basis of the transmission power control information sent from the radio base station. The optimum transmission power under present environment is obtained by a control part 9. When the transmission power based on the transmission power control information exceeds the optimum transmission power, a limiting part 12 limits the transmission power to be the optimum transmission power. Thereby the transmission power can be prevented from increasing up to the maximum power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CDMA (Code Div.)
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control method and apparatus that performs radio communication using an ision multiple access (Ision Multiple Access) method, receives transmission power control information transmitted from a radio base station, and controls transmission power to optimal power, and a mobile communication terminal.

[0002]

2. Description of the Related Art Conventionally, in a mobile communication terminal such as a mobile phone using the CDMA system, it is necessary to minimize the transmission power transmitted from the mobile communication terminal to a base station. This is to prevent radio waves transmitted from the own terminal to the base station from becoming an interference wave in wireless communication between another mobile communication terminal and the base station.

[0003] Conventionally, transmission power control information for controlling the transmission power of each mobile communication terminal is transmitted from the base station to each mobile communication terminal, and the transmission power control information addressed to the terminal increases the transmission power. If the instruction, the terminal adds the relative power value specific to the system to the current transmission power to perform transmission, and if the transmission power control information indicates that the transmission power is to be reduced, the terminal uses the system-specific relative power value. The operation of subtracting the relative power value from the current transmission power and performing transmission is repeated, and the transmission power of each mobile communication terminal is sequentially controlled.

[0004]

However, conventionally, when the radio wave transmitted from the base station to the mobile communication terminal cannot be received by the terminal due to some external factor, the user information is interrupted at the same time. In addition, the transmission power control information transmitted from the base station to the terminal cannot be received at the same time.

[0005] When it is impossible to receive accurate transmission power control information, the terminal accidentally transmits the information at that time.
When interpreted as an instruction to increase the transmission power, the mobile communication terminal continuously increases the transmission power based on this information, and increases the transmission power to the maximum transmission power of the mobile communication terminal.

[0006] The base station controls transmission power of each mobile communication terminal by transmitting transmission power control information so that the reception power from each mobile communication terminal becomes equal and optimal.
I try to keep a balance. However, one terminal
As described above, if the transmission is performed at the maximum transmission power ignoring this balance, the communication radio wave due to the maximum transmission power becomes an interference wave to the communication of another user, and the call connection of the other user is disconnected. This causes a problem of causing the error.

[0007] The present invention has been made in view of the above-described circumstances, and even when a situation occurs in which transmission power control information cannot be received, transmission power does not increase to the maximum transmission power without limit. A power control method and device, and a mobile communication terminal.

[0008]

A transmission power control method according to the present invention transmits and receives radio waves to and from a radio base station and adjusts transmission power based on transmission power control information sent from the radio base station. In the transmission power control method of the mobile communication terminal to determine the optimal transmission power under the current environment on the mobile communication terminal side, if the transmission power adjusted based on the transmission power control information exceeds the optimal transmission power, The transmission power is limited to the optimum transmission power.

A transmission power control method according to a second aspect is characterized in that a margin of transmission power that can follow an instantaneous variation such as fading is added to the optimum transmission power.

[0010] A transmission power control method according to a third aspect is characterized in that the optimum transmission power is obtained from desired wave reception power and broadcast information sent from a radio base station.

A transmission power control apparatus according to the present invention transmits and receives radio waves to and from a radio base station and adjusts transmission power based on transmission power control information sent from the radio base station. A control unit for obtaining an optimum transmission power under the current environment; and a limiter for limiting the transmission power to the optimum transmission power when the transmission power adjusted based on the transmission power control information exceeds the optimum transmission power. , Is provided.

In the transmission power control apparatus according to a fifth aspect, the limiting means limits the transmission power to a value obtained by adding a margin of the transmission power capable of following an instantaneous variation such as fading to the optimum transmission power. I do.

According to a sixth aspect of the present invention, in the transmission power control apparatus, the control unit may determine the optimum transmission power as a desired wave reception power,
It is obtained from the broadcast information sent from the wireless base station.

A mobile communication terminal according to the present invention transmits and receives radio waves to and from a radio base station and adjusts transmission power based on transmission power control information sent from the radio base station. Item 7 is characterized in that the transmission power control device according to any one of Items 4 to 6 is mounted.

According to the above configuration, the transmission power is limited even if the transmission power control information from the base station is erroneously recognized as an instruction to increase the transmission power on the mobile communication terminal side even if the line condition is deteriorated due to some external factor. So it does not rise to its maximum capacity.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a mobile communication terminal according to one embodiment of the present invention. The mobile communication terminal includes a receiving antenna 1, a transmitting antenna 2, a radio unit 3 to which the antennas 1 and 2 are connected, and a receiver 3 of the radio unit 3.
A demodulation unit 4 for demodulating a signal received from the receiving antenna 1; a desired wave reception power measurement unit 5 receiving a demodulated signal from the demodulation unit 4 as an input signal; a broadcast information decoding unit 6 and a transmission power control information decoding unit 7 And a transmission unit 8 for generating a transmission signal to be transmitted from the mobile communication terminal to the radio base station and transmitting the transmission signal from the transmission antenna 2 through the gain control amplifier 321 in the transmitter 32 of the radio unit 3.

Further, the mobile communication terminal reads the information from the desired wave reception power measuring section 5 and the information from the broadcast information decoding section 6, extracts necessary parameters from the information, and determines the optimum transmission power value as described later. Main control unit 9 to calculate
And a margin adding unit 10 for adding, as a margin, an increase in transmission power for following an instantaneous variation such as fading to the value calculated by the main control unit 9 to determine an upper limit value of transmission power; and transmission power control information. A gain control unit 11 that takes in the transmission power information obtained by the decoding unit 7 and determines a gain, and restricts a gain command signal output from the gain control unit 11 and outputs the signal to a gain control amplifier 321 of the transmitter 32. And a limit value obtained by adding the margin to the optimum transmission power value is given to the limiter unit 12 as a limit value.

FIG. 2 is a flowchart showing an operation procedure of the main control unit 9 which performs a transmission power control operation in a communication state. First, the main control unit 9 sets the desired wave reception power measurement unit 5
Extracts the information measured by Rbcch (dB
m) (S1). Next, information from the broadcast information decoding unit 6 is taken out, and the base station (BTS: Base
The transmission power of the Trasceiver Station is held as Tbcch (dBm) (S2).

Thereafter, the base station reception target [Eb / Io] (dB) obtained from the decode information of the broadcast information decoding unit 6 is held (S3), and the base station uplink target similarly obtained from the decode information of the broadcast information decode unit 6 is held. The interference amount is held as Ibs (dBm / Hz) (S4), and a preset adjustment parameter α is read (S5). The parameter α is a value adjusted according to the characteristics of the used channel.

Next, the optimum transmission power Tms is calculated from the above values.
Tms = [Eb / Io] + Tbcch−Rbcch + Ibs
+ Α (S6), and outputs the optimum transmission power Tms (dBm) as a limiter value used in the limiter 12 (S6).
7).

The main controller 9 outputs the value of the optimum transmission power calculated as described above,
2 is a gain control unit 1 using the optimum transmission power value as a limit value.
Limit the output command of 1. For this reason, the transmission power control information decoding unit 7 misidentifies and outputs unknown information as “transmission power increase command” information, and the gain control unit 11 sequentially
In the present embodiment, the upper limit value of the transmission power increase command is set to the optimum transmission power value by the limiter unit 12 even if the gain command to increase the transmission power and eventually increase to the maximum power determined by the system is output. The gain control amplifier 321 is controlled by the limited command. Therefore, it is possible to prevent the transmission power from rising to the maximum power without limitation. Further, in the present embodiment, FIG.
As described above, since the margin adding unit 10 is provided to further add a margin to the value of the optimum transmission power as the limit value, it is possible to cope with the adverse effect of instantaneous fluctuation such as fading.

FIG. 3 shows the gain controller 11 and the limiter 1
6 is a flowchart showing an operation procedure of the second embodiment. The gain control unit 11, which has received the information from the transmission power control information decoding unit 7, determines whether or not this information is an "instruction to increase the transmission power" (S10). The transmission power control information is T
It is included in the transmission signal from the base station as a PC bit, and by looking at the TPC bit, it is possible to determine whether the instruction is an up (power up) instruction or a down (power down) instruction.

When power-up is instructed, the gain controller 11 adds the transmission power previously transmitted to the transmission power increase ΔP (dB) determined by the system (the system including the base station and the communication terminal) to the transmission power. ) Is output as a gain command. Limiter unit 1 receiving this gain command
2 reads a value obtained by adding a margin to the output value of the main control unit 9 as a limit value (S11).

The limiter 12 determines whether the command value from the gain controller 11 exceeds the limit value (S1).
2). If it has exceeded, do nothing (output the same gain command as the previous transmission power gain command to the gain control amplifier 321. That is, leave it as it is), and return to S10.

If the command value from the gain control unit 11 does not exceed the limit value, the limiter unit 12 outputs the command value from the gain control unit 11, that is, the gain command value for increasing ΔP to the gain control amplifier 321. The control voltage of the amplifier 321 is controlled (S13).

On the other hand, when it is determined that the power is not up, the gain control section 11 determines whether or not a power down instruction is made (S14). If it is not power down, the process returns to S10 and does nothing. That is, the transmission power is not changed as it is.

If it is determined that the instruction is a power down instruction, the gain control section 11 outputs a gain instruction to decrease ΔP, and outputs an instruction to decrease the gain corresponding to ΔP to the gain control amplifier 321 (S15). It returns to S10.

According to such an operation procedure, even if the line condition is deteriorated due to some external factor and the transmission power control information from the base station is erroneously recognized as “instruction to increase transmission power”, the output of gain control section 11 Is limited by the limiter unit 12, the value of the transmission power actually output from the mobile communication terminal is limited to the optimum transmission power under the environment or the transmission power obtained by adding a margin thereto. Generation of an interference wave / interference wave for the terminal is avoided.

[0029]

According to the present invention, even if the transmission power control information from the base station is erroneously recognized as an instruction to increase the transmission power on the mobile communication terminal side, the optimal transmission under the current environment is performed even if the line condition deteriorates. Since the upper limit of the transmission power is limited to the power or a value obtained by adding a margin to the power, it is possible to suppress the transmission power from being increased more than necessary.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile communication terminal according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of a main control unit shown in FIG.

FIG. 3 is a flowchart illustrating an operation procedure of a gain control unit and a limiter unit illustrated in FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reception antenna 2 transmission antenna 3 reception unit 4 demodulation unit 5 desired wave reception power measurement unit 6 broadcast information decoding unit 7 transmission power control information decoding unit 8 transmission unit 9 main control unit 10 margin addition unit 11 gain control unit 12 limiter Part 31 Receiver 32 Transmitter 321 Gain control amplifier

Claims (7)

[Claims] 1. A transmission power control method for a mobile communication terminal that transmits and receives radio waves to and from a radio base station and adjusts transmission power based on transmission power control information sent from the radio base station. On the communication terminal side, determine the optimum transmission power under the current environment, and when the transmission power adjusted based on the transmission power control information exceeds the optimum transmission power, limit the transmission power to the optimum transmission power. Characteristic transmission power control method. 2. The transmission power control method according to claim 1, wherein a margin of transmission power capable of following an instantaneous variation such as fading is added to the optimum transmission power. 3. The transmission power control method according to claim 1, wherein said optimum transmission power is obtained from desired signal reception power and broadcast information sent from a radio base station. 4. A transmission power control apparatus for transmitting and receiving radio waves to and from a radio base station and adjusting transmission power based on transmission power control information sent from the radio base station, comprising: A control unit that obtains power, and a limiter that limits the transmission power to the optimum transmission power when the transmission power adjusted based on the transmission power control information exceeds the optimum transmission power. Transmission power control device. 5. The transmission power control device according to claim 4, wherein the limit means limits the transmission power to a value obtained by adding a margin of transmission power capable of following an instantaneous variation such as fading to the optimum transmission power. . 6. The transmission power control according to claim 4, wherein the control unit obtains the optimum transmission power from a desired wave reception power and broadcast information sent from a radio base station. apparatus. 7. A mobile communication terminal that transmits and receives radio waves to and from a wireless base station and adjusts transmission power based on transmission power control information sent from the wireless base station. A mobile communication terminal comprising the transmission power control device according to claim 1.