BASE STATION, MOBILE STATION, AND POWER CONTROL METHOD

• US 20100048236A1
• Filed: 06/13/2006
• Published: 02/25/2010
• Est. Priority Date: 06/14/2005
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Sawahashi, Mamoru, Higuchi, Kenichi, Atarashi, Hiroyuki
• Granted Patent: US 8,290,528 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/362 Aspects of the step size

Abstract

A base station includes: means that derives a transmission power of a mobile station based on receive quality of an uplink pilot channel; means that reports the derived transmission power to the mobile station; and means that receives a control channel transmitted by the mobile station according to the reported information. Accordingly, irrespective of transmission power history over a past continuous time, the mobile station receives an instruction on the transmission power from the base station each time when transmitting a packet so as to be able to adjust the transmission power.

Claims

1. A base station comprising:

means that derives a transmission power of a mobile station based on receive quality of an uplink pilot channel;

means that reports the derived transmission power to the mobile station; and

means that receives a control channel transmitted by the mobile station according to the reported information.

2. The base station as claimed in claim 1, wherein the base station derives a relative power amount by which the mobile station needs to change a transmission power based on relationship between the receive quality of the uplink pilot channel and receive quality that the control channel needs to satisfy.

3. The base station as claimed in claim 1, wherein the base station derives an absolute power amount to which the mobile station needs to change a transmission power based on relationship between the receive quality of the uplink pilot channel and a transmission power value of the pilot channel.

4. The base station as claimed in claim 1, wherein the base station reports a pilot channel and the transmission power using a downlink, and

receives the uplink pilot channel that is transmitted with a power derived by the mobile station based on an average propagation loss between the mobile station and the base station.

5. The base station as claimed in claim 4, wherein the propagation loss is derived from the receive quality and the transmission power value of the pilot channel of the downlink.

6. The base station as claimed in claim 1, wherein the base station receives both or one of a first pilot channel in which a symbol mapping pattern is constant and a second pilot channel in which a symbol mapping pattern is variable.

7. The base station as claimed in claim 4, wherein the base station causes the mobile station that is transmitting traffic data to transmit the control channel using a power derived based on the uplink pilot channel, and

causes the mobile station that is not yet transmitting traffic data to transmit the control channel using a power derived based on the average propagation loss.

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

means that determines a frequency chunk usable for the mobile station to transmit traffic data and determines a transmission power of the mobile station.

9. The base station as claimed in claim 8, wherein the transmission power and the frequency chunk are determined such that the transmission power exceeds a predetermined threshold and that more chunks are used.

10. A base station comprising:

means that transmits a common pilot channel;

means that derives a plurality of transmission powers of a shared control channel based on receive quality of a plurality of common pilot channels reported by an uplink; and

means that reports the shared control channel to a plurality of mobile stations using the derived transmission powers.

11. The base station as claimed in claim 10, wherein the base station reports the derived transmission powers separately to the mobile stations receiving traffic data.

12. The base station as claimed in claim 10, wherein the base station reports one of the derived transmission powers to the mobile stations that are receiving traffic data.

13. The base station as claimed in claim 10, wherein the base station reports the shared control channel, using a predetermined transmission power, to a mobile station that is not receiving traffic data.

14. The base station as claimed in claim 10, the base station comprising a coder for coding data for one or more mobile station as a unit, wherein the data for one or more mobile station is transmitted using a same transmission power.

15. A mobile station comprising:

means that receives a transmission power using a downlink when a base station derives the transmission power by which the mobile station needs to change based on receive quality of an uplink pilot channel; and

means that changes its transmission power based on reported information to transmit a control channel.

16. The mobile station as claimed in claim 15, wherein the mobile station receives a pilot channel and the transmission power value using the downlink;

derives a transmission power based on an average propagation loss between the mobile station and the base station; and

transmits the uplink pilot channel using the derived transmission power.

17. The mobile station as claimed in claim 15, wherein the mobile station transmits both or one of a first pilot channel in which a symbol mapping pattern is constant and a second pilot channel in which a symbol mapping pattern is variable.

18. A power control method, wherein:

a base station derives a transmission power by which a mobile station needs to change based on receive quality of an uplink pilot channel,

reports the derived transmission power to the mobile station, and

the mobile station changes its transmission power according to the reported information to transmit a control channel.