Mobile communication system

• US 6,243,591 B1
• Filed: 09/30/1997
• Issued: 06/05/2001
• Est. Priority Date: 10/08/1996
• Status: Expired due to Fees

• Current Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Original Assignee: NEC Corporation
• Inventors: Takemura, Narihira
• Primary Examiner(s): BANKS HAROLD, MARSHA DENISE
• Application Number:
  US08/940,293
• Time in Patent Office: 1,344 Days
• Field of Search: 455/69, 455/522, 455/70, 455/67.1, 455/68, 455/88, 455/115, 455/127, 455/226.1, 455/226.2
• US Class Current: 455/522
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/18 TPC being performed according to specific parameters

Abstract

A mobile communication system includes a base station and a mobile station. The base station transmits base station information containing transmission power information. The mobile station can control the transmission power thereof in accordance with the transmission power information in the received base station information and a reception electric field strength.

Claims

1. A mobile communication system comprising:

a base station for transmitting base station information containing transmission power information on the power level with which the base station is transmitting signals to a mobile station, and a code specifying the particular base station itself;

a mobile station which controls its own transmission power in accordance with (i) the transmission power information in the received base station information on the power level with which the base station is transmitting signals to the mobile station, and (ii) a reception electric field strength of the signals received from the base station by the mobile station as measured by the mobile station;

wherein the mobile station stores an array of data comprised of (i) a plurality of base station transmission power levels and (ii) a plurality of reception electric field strengths for each of the plurality of base station transmission power levels, and wherein a particular base station transmission power level and a particular reception electric field strength indicate a particular mobile station transmission power level, from which a selected transmission power with which the mobile station is to perform transmission is selected from the array of data on the basis of (i) the transmission power information received from the base station, and (ii) the reception electric field strength measured by the mobile station; and

the mobile station performs a transmission to the base station at said selected transmission power.

2. A mobile communication system comprising:

a base station for transmitting base station information containing transmission power information on the power level with which the base station is transmitting signals to a mobile station, and a code specifying the particular base station itself, and

a mobile station which controls its own transmission power in accordance with (i) the transmission power information in the received base station information on the power level with which the base station is transmitting signals to the mobile station, and (ii) a reception electric field strength of the signals received from the base station by the mobile station as measured by the mobile station,

wherein the mobile station stores an array of data comprised of (i) a plurality of base station transmission power levels and (ii) a plurality of reception electric field strengths for each of the plurality of base station transmission power levels, and wherein a particular base station transmission power level and a particular reception electric field strength indicate a particular mobile station transmission power level,

wherein the mobile station stores a function for calculating a transmission power with which the mobile station is to perform transmission on the basis of (i) the transmission power information received from the base station, and (ii) the reception electric field strength measured by the mobile station and determines a calculated transmission power by performing a calculation using the stored function; and

the mobile station performs a transmission to the base station at said calculated transmission power.

3. A mobile communication system comprising:

a mobile communication station including an antenna, a transmitting section, a receiving section, an electric field strength measuring section for measuring an electric field strength of a reception signal from a base station, and a control section for controlling operations of the respective sections to communicate with a predetermined one of a plurality of base stations in a communication service area having the plurality of base stations;

each of the pluralitiy of base stations transmits base station information containing a transmission power value on the power level with which the base station is transmitting signals to the mobile station;

the mobile communication station including,

(a) base station transmission power detecting means for detecting the transmission power value of a predetermined one of the base stations from the base station information contained in a reception signal from the base station on the power level with which the base station is transmitting signals to the mobile station,

(b) a transmission power control section for controlling the mobile communication station transmission power output from said transmitting section on the basis of,

(i) the base station transmission power value transmitted by the base station and detected by the base station transmission power detecting means, and

(ii) the electric field strength of the reception signal measured by said electric field strength measuring section of the mobile communication station,

wherein the mobile communication station stores an array of data table comprised of (i) a plurality of base station transmission power levels and (ii) a plurality of reception electric field strengths for each of the plurality of base station transmission power levels, and wherein a particular base station transmission power level and a particular reception electric field strength indicate a particular mobile station transmission power level with which the mobile communication station is to perform transmission to the base station with which communication is currently performed.

4. A system according to claim 3, wherein said transmission power control section of the mobile communication station receives outputs from (i) said base station transmission power detection means and (ii) said electric field strength measuring section, and controls said transmitting section to ensure proper communication with the base station and perform transmission with a transmission power which minimizes power consumption in accordance with (i) the transmission power value of the base station with which communication is currently being performed and (ii) the reception electric field strength which is currently measured.

5. A system according to claim 3, wherein the mobile communication station stores a function for calculating a transmission power with which the mobile communication station is to perform transmission with respect to the base station with which communication is currently being performed, on the basis of (i) the transmission power value transmitted from said base station, and (ii) the electric field strength of the reception signal which is measured by said electric field measuring section, and determines a calculated transmission power for the mobile communication station by performing a calculation using the stored function.

6. A transmission power control method for a mobile communication station comprising:

a first step of receiving base station information transmitted from a base station and containing transmission power information on the transmission power value with which the base station is transmitting signals to a mobile station,

a second step of obtaining the transmission power value of the base station from the transmission power information of the base station information,

a third step of measuring a reception electric field strength at the mobile station of a signal transmitted from the base station,

a fourth step of determining a transmission power with which transmission by the mobile station is to be performed with respect to the base station with which communication is currently being performed on the basis of (i) the transmission power value of the base station, and (ii) the reception electric field strength, using a table of array data comprised of (i) a plurality of base station transmission power levels and (ii) a plurality of reception electric field strengths for each of the plurality of base station transmission power levels, and wherein a particular base station transmission power level and a particular reception electric field strength indicate a particular mobile station transmission power level with which transmission is to be performed,

a fifth step of determining on the basis of the result obtained in the fourth step whether the transmission power used by the mobile station for the current transmission is to be changed, and

a sixth step of changing the transmission power used by the mobile station when it is determined as a result of the fifth step that the currently used transmission power is to be changed.

7. A method according to claim 6, wherein:

the mobile station stores a function for calculating a transmission power with which the mobile station is to perform transmission on the basis of (i) the transmission power information received from the base station, and (ii) the reception electric field strength measured by the mobile station, and determines a calculated transmission power by performing a calculation using the stored function; and

the mobile station performs a transmission to the base station at said calculated transmission power.