JP5315038B2 - Wireless communication terminal and transmission power control method thereof - Google Patents

Description

  The present invention relates to a wireless communication terminal that performs wireless communication with a base station and a transmission power control method thereof.

  In a radio communication system using radio waves, the amount of attenuation of radio waves increases as the distance increases, making it difficult for a mobile station (wireless communication terminal) far away from the base station to communicate with the base station. Therefore, transmission power control is performed for the mobile station to control the transmission power of the mobile station so that the reception power at the base station is the same.

  For this purpose, the base station measures the strength of the signal from the mobile station, transmits a command for specifying the transmission power to be set to the mobile station so that the strength is constant, and sets the transmission power to the command. A technique is known (see Patent Document 1).

There has also been proposed a technique in which a mobile station measures the strength of a signal from a base station and sets the transmission power in inverse proportion to the strength (see Patent Document 2).
JP-A-10-79699 JP-A-10-126283

  Currently, in the mobile phone system, the control of the transmission power level of the mobile station and the base station is performed based on a predetermined standard.

  Control of transmission power on the mobile phone terminal side is generally performed as instructed by a command from the base. However, even within this standard range, strictly speaking, the level required for each base station managed by each operator (communication carrier) differs, and the level of the signal received by the base station from the mobile phone terminal is not necessarily desired. It may not be the level. In other words, there is a range of standards and the control from the base station varies from operator to operator, and optimization for the base station has not been achieved.

  The present invention has been made in such a background, and corrects the transmission power variation of the wireless communication terminal required for each communication carrier, so that the transmission power to the base station can be appropriately adjusted even if the communication carrier changes. It can be maintained.

Radio communications terminal that by the present invention, a wireless communication unit capable of controlling the transmission power, means for detecting a received signal strength from the base station, corrects the detection value of the received signal strength for each communication carrier When determining transmission power based on a correction table to be detected and a detected value of received signal strength from a base station, based on a value obtained by correcting the detected value with reference to the correction table for a communication carrier of the base station Means for determining transmission power and control means for controlling the wireless communication unit so as to obtain the determined transmission power are provided.

  The wireless communication terminal corrects according to the communication carrier when determining the transmission power based on the detected value of the received signal strength without receiving the designated value of the transmission power from the base station.

  The present invention can also be understood as a transmission power control method for a wireless communication terminal.

  According to the present invention, when controlling the transmission power of the wireless communication terminal, the transmission power is corrected in response to the operator. Therefore, even if the operator changes, the transmission power to the base station is appropriately maintained according to the request of each operator. It becomes possible to do.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram for explaining a schematic configuration of the first embodiment of the present invention.

  A mobile phone terminal 20 as a wireless communication terminal is connected to base stations 10a and 10b of different communication carriers, that is, operators (here, two operators A and B) in a plurality of countries (or regions: the same applies hereinafter), and calls are made. And communication services.

  Each base station adaptively controls the increase / decrease of the transmission power of each mobile phone terminal in the area so that the received signal strengths from the plurality of mobile phone terminals received by each base station are all at a desired level. In order to control the transmission power, the mobile phone terminal 20 sequentially receives a transmission power designation command from the base station in any area of the base stations 10a and 10b, and an appropriate transmission power level at that time is designated. .

  As shown in FIG. 1, when an instruction of a power level “5” is received from a certain operator A, the transmission power correction table 30 corresponding to the operator is referred to, and for that operator, the transmission power is increased by one level and the power level “4”. " (Here, it is assumed that the smaller the level value is, the higher the power level is.) On the other hand, when an instruction of the same power level “5” is received from another operator B, the operator corresponding transmission power correction table 30 is referred to. Then, for the operator, the transmission power is lowered by one level to the power level “6”.

  As a result, even if the required transmission power level value is the same, it is possible to correct the actual required transmission power variation by the operator.

  FIG. 2 is a block diagram showing a schematic internal configuration of the mobile phone terminal 20 in the present embodiment.

  The command and data from the base station received by the antenna 25 are demodulated and decoded by the receiving unit 22 and input to the control unit 21 as received data Rxdata. The control unit 21 is configured by a CPU or the like, and performs predetermined processing and control. The storage unit 24 includes a memory (ROM, RAM, flash memory, etc.) for storing various data in addition to a program executed by the CPU. The above-mentioned transmission power correction table 30 corresponding to the operator is also stored in the storage unit 24. Data Txdata to be transmitted is encoded and modulated by a transmission unit (wireless communication unit) 23, amplified by a power amplifier at a transmission power level according to a gain control signal from the control unit 21, and output as a radio wave from an antenna 25. The

  3A and 3B show examples of contents of two types of operator-corresponding transmission power correction tables 30a and 30b stored in the storage unit 24 as the operator-corresponding transmission power correction table 30 shown in FIG. ing. The transmission power correction table 30a corresponding to the operator preferably has a value (specified value) designated as the transmission power level requested by the operator for the mobile phone terminal and is actually set for each operator corresponding to each value. It is a data table which defined correspondence with the value (desired value) of a power level.

  The operator-corresponding transmission power correction table 30b is substantially the same as the operator-corresponding transmission power correction table 30a, but the value of the difference between the specified value and the desired value is defined as the value of the transmission power level corresponding to each operator. . Conventionally, the cellular phone terminal 20 performs transmission at the transmission power level specified by the transmission power designation command. In the present invention, when a transmission power designation command is received, the transmission power is determined by correcting the value of the transmission power according to the operator.

  FIG. 4 is a flowchart showing a schematic procedure of processing relating to transmission power determination of the mobile phone terminal according to the present embodiment.

  After connecting to the base station (S11), the mobile phone terminal 20 sequentially receives a transmission power designation command from the base station (S12). The mobile phone terminal can identify the operator through communication with the base station. Therefore, the transmission power correction table 30 stored in advance in the terminal is referred to, the transmission power corresponding to the operator is confirmed, and the transmission power is corrected according to the correction value (S13). Thereafter, the cellular phone terminal 20 controls the power amplifier in the transmission unit 23 so as to obtain the corrected transmission power.

  FIG. 5 is a conceptual diagram for explaining a schematic configuration of the second embodiment of the present invention. In the embodiment of FIG. 1, the mobile phone terminal determines the transmission power in accordance with an instruction from the base station, but in this embodiment, the mobile phone terminal autonomously determines the transmission power. However, as in the first embodiment, the transmission power is corrected according to the operator. In this example, when determining the transmission power based on the detection value of the received signal strength level (reception level) from the base station, the transmission power is indirectly corrected by correcting the detection value of the reception level to correspond to the operator. Correct. For example, a received signal strength indicator (RSSI) value can be used as the received signal strength.

  In the example of FIG. 5, for example, even if the reception level of the operator A from the base station 10a and the reception level of the operator B from the base station 10b are the same, the reception level is corrected corresponding to the operator, The determined desired transmission power can vary.

  FIG. 6 is a block diagram showing a schematic internal configuration of the mobile phone terminal 20 according to the second embodiment. The configuration is basically the same as that of the first embodiment. The difference is that the table in the storage unit 24 replaces the operator-corresponding reception level correction table 40 instead of the operator-corresponding transmission power correction table 30, and the reception level is changed (level off-set) in the control unit 21. It is.

  FIGS. 7A and 7B show examples of contents of two types of operator-corresponding reception level correction tables 40a and 40b stored in the storage unit 24 as the operator-corresponding reception level correction table 40 shown in FIG. ing. The operator corresponding reception level correction table 40a includes a reception level value (detection value) detected by the terminal, and a reception level value (desired value) corresponding to a transmission power level value that is preferably set for each operator. It is a data table that defines the correspondence.

  The operator-corresponding reception level correction table 40b is substantially the same as the operator-corresponding reception level correction table 40a, but defines the difference between the detected value and the desired value as the value of the reception level corresponding to each operator.

  FIG. 8 is a flowchart showing a schematic procedure of processing relating to transmission power determination of the mobile phone terminal according to the second embodiment.

  After connecting with the base station (S21), the mobile phone terminal 20 detects the reception level sequentially based on the signal received from the base station (S22). Next, with reference to the operator corresponding reception level correction table 40, the reception level correction value corresponding to the operator for the detected value is obtained (S23). Therefore, the transmission power is determined based on the corrected reception level (S24). The method of determining the transmission power based on the reception level is to set the transmission power to be larger as the reception level is lower, and may be an existing method based on a predetermined standard. Thereafter, the cellular phone terminal 20 controls the power amplifier in the transmission unit 23 so as to obtain the corrected transmission power.

  As described above, according to the first and second embodiments, the mobile phone terminal adaptively controls increase / decrease of its own transmission power by identifying the operator, so that the control in a short cycle within several hundred msec is possible. It becomes possible, and the level of the transmission power from the mobile phone terminal received by the base station is always appropriate.

  The preferred embodiments of the present invention have been described above, but various modifications and changes other than those mentioned above can be made. For example, although a mobile phone system has been described, the present invention can be applied to an arbitrary wireless communication system using a base station. Further, the correction table corresponding to the operator may be a correction table corresponding to the country (or region) identified by the country code instead of the operator. Therefore, in this specification, “operator correspondence” includes “country (or region) correspondence” in a broad sense.

It is a conceptual diagram for demonstrating schematic structure of the 1st Embodiment of this invention. It is the block diagram which showed the schematic internal structure of the mobile telephone terminal in 1st Embodiment. It is the figure which showed the example of the transmission power correction table corresponding to operators shown in FIG. It is the flowchart which showed the general | schematic procedure of the process regarding the transmission power determination of the mobile telephone terminal in 1st Embodiment. It is a conceptual diagram for demonstrating schematic structure of the 2nd Embodiment of this invention. It is the block diagram which showed the schematic internal structure of the mobile telephone terminal in 2nd Embodiment. It is the figure which showed the example of the operator corresponding | compatible reception level correction | amendment table shown in FIG. It is the flowchart which showed the schematic procedure of the process regarding the transmission power determination of the mobile telephone terminal in 2nd Embodiment.

Explanation of symbols

10a, 10b ... base station, 20 ... mobile phone terminal, 21 ... control unit, 22 ... reception unit, 23 ... transmission unit, 24 ... storage unit, 25 ... antenna, 30, 30a, 30b ... operator-compatible transmission power correction table, 40, 40a, 40b ... Reception level correction table for operator

Claims (4)

A wireless communication unit capable of controlling transmission power;
Means for detecting received signal strength from the base station;
A correction table for correcting the detected value of the received signal strength for each carrier,
When determining the transmission power based on the detected value of the received signal strength from the base station, the transmission power is determined based on a value obtained by correcting the detected value with reference to the correction table for the communication carrier of the base station. Means,
A wireless communication terminal comprising: control means for controlling the wireless communication unit so that the determined transmission power can be obtained. Wherein the correction table, the wireless communication terminal according to claim 1 wherein "operators each" a cash forte, a correction table for correcting the detection value for each country or region. A method of controlling transmission power of a wireless communication terminal that performs wireless communication with a base station,
Detecting received signal strength from the base station;
When determining the transmission power based on the detection value of the received signal strength from the base station, a correction table for correcting the detection value of the received signal strength for each communication carrier is used to set the detected value to the communication business of the base station. Correcting for each person,
Determining transmission power based on the corrected value;
A transmission power control method for a radio communication terminal, comprising: controlling transmission power so that the determined transmission power is obtained. Wherein instead of "every telecommunications carrier", transmission power control method of a wireless communication terminal according to claim 3 for correcting the detection value for each country or region.

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