Base station and transmission power control method

• US 20060111137A1
• Filed: 11/02/2005
• Published: 05/25/2006
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Okajima, Ichiro, Mori, Shinichi, Umeda, Narumi
• Granted Patent: US 7,483,713 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

A base station is disclosed. The base station includes: a service area status determination unit configured to determine status of a service area of the base station based on received signals from mobile stations; a total transmission power determination unit configured to determine status of total transmission power of the base station based on total transmission power of surrounding base stations; a transmission power determination unit configured to determine transmission power of a common control channel of the base station based on the status of the service area and the status of the total transmission power; and a transmission power setting unit configured to set the transmission power determined by the transmission power determination unit.

Claims

1. A base station comprising:

a service area status determination unit configured to determine status of a service area of the base station based on received signals from a plurality of mobile stations;

a total transmission power determination unit configured to determine status of total transmission power of the base station based on total transmission power of surrounding base stations;

a transmission power determination unit configured to determine transmission power of a common control channel of the base station based on the status of the service area and the status of the total transmission power; and

a transmission power setting unit configured to set the transmission power determined by the transmission power determination unit.

2. The base station as claimed in claim 1, the base station further comprising:

an interference amount measurement unit configured to measure an uplink interference amount based on the received signals from the mobile stations; and

a line status determination unit configured to determine line status of the base station based on the uplink interference amount and transmission power in the surrounding base stations;

wherein the transmission power determination unit determines the transmission power of the common control channel of the base station based on the line status.

3. The base station as claimed in claim 2, the base station further comprising a wireless resource exchanging unit configured to exchange at least one of the status of the service area, the total transmission power, the uplink interference amount and the transmission power with a surrounding base station that forms an adjacent cell adjacent to a cell formed by the base station.

4. The base station as claimed in any one of claims 1-3, wherein the service area status determination unit accumulates received quality of the received signals to obtain a cumulative value and determines the status of the service area of the base station based on comparison between the cumulative value and a predetermined reference value of received quality.

5. The base station as claimed in any one of claims 1-3, wherein the total transmission power determination unit determines the status of the total transmission power of the base station based on an average of total transmission power values of the surrounding base stations.

6. The base station as claimed in claim 2, wherein the line status determination unit determines the line status of the base station based on a sum of the uplink interference amount and the transmission power in the surrounding base stations.

7. The base station as claimed in any one of claims 1-3, wherein the transmission power determination unit increases the transmission power of the common control channel when the status of the total transmission power of the base station is less than a predetermined threshold.

8. A transmission power control method for use in a base station, the transmission power control method comprising:

a receiving step of receiving signals from a plurality of mobile stations;

a service area status determination step of determining status of a service area of the base station based on the received signals from the mobile stations;

a total transmission power determination step of determining status of total transmission power of the base station based on total transmission power of surrounding base stations;

a transmission power determination step of determining transmission power of a common control channel of the base station based on the status of the service area and the status of the total transmission power; and

a transmission power setting step of setting the transmission power determined in the transmission power determination step.

9. The transmission power control method as claimed in claim 8, the transmission power control method further comprising:

an interference amount measurement step of measuring an uplink interference amount based on the received signals from the mobile stations;

a receiving step of receiving the uplink interference amount and transmission power in the surrounding base stations; and

a line status determination step of determining line status of the base station based on the uplink interference amount and the transmission power in the surrounding base stations;

wherein, in the transmission power determination step, the base station determines the transmission power of the common control channel of the base station based on the line status.