WIRELESS COMMUNICATION SYSTEM AND METHOD OF CONTROLLING A TRANSMISSION POWER

• US 20090247211A1
• Filed: 11/02/2006
• Published: 10/01/2009
• Est. Priority Date: 11/04/2005
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kuroda, Nahoko
• Granted Patent: US 8,515,480 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A base station is configured to be able to set appropriate transmission power of an uplink wireless channel used for a plurality of mobile stations to share wireless resources and to transmit data.

The base station notifies each mobile station of transmission power information on an uplink RACH, the mobile station transmits transmission delay estimation information on the RACH to the base station over the RACH at transmission power set based on the transmission power information, and the base station changes the transmission power information on the RACH according to the transmission delay estimation information and notifies the mobile station of the changed transmission delay estimation information. The mobile station retransmits data or a preamble if the mobile station does not receive, over a downlink AICH, an ACK that is a notification that the base station has received the data or the preamble correctly after a predetermined time since the mobile station transmits the data or the preamble over the RACH. The base station transmits the transmission power information over a BCH and a CPICH transmitted to a plurality of mobile stations.

Claims

1. A method of controlling a transmission power, causing a base station to control a transmission power of a mobile station, comprising steps of:

causing the base station to notify of transmission power information on a wireless channel of an uplink;

causing the mobile station to transmit transmission delay estimation information on the wireless channel; and

causing the base station to change the transmission power information on the wireless channel according to the transmission delay estimation information, and to notify the mobile station of the changed transmission power information on the wireless channel.

2. The method of controlling a transmission power according to claim 1, further comprising a step of

causing the mobile station to retransmit data or a preamble after a predetermined time since transmitting the data or the preamble over the wireless channel if the mobile station does not receive, over a downlink control channel, acquisition indicator information on a notification of which the base station has received the transmitted data or preamble correctly.

3. The method of controlling a transmission power according to claim 1,

wherein the base station transmits the transmission power information over a broadcast channel for transmission to a plurality of mobile stations.

4. The method of controlling a transmission power according to claim 1,

wherein the mobile station transmits the transmission delay estimation information over the wireless channel.

5. The method of controlling a transmission power according to claim 2,

wherein the mobile station notifies of number of the transmission or the retransmission of the data or the preamble by the transmission delay estimation information.

6. The method of controlling a transmission power according to claim 2,

wherein the mobile station notifies of a time elapsed since initial transmission of the data or the preamble by the transmission delay estimation information.

7. The method of controlling a transmission power according to claim 2,

wherein the mobile station notifies of a timing of initial transmission of the data or the preamble by the transmission delay estimation information.

8. The method of controlling a transmission power according to claim 2,

wherein the mobile station retransmits the data or the preamble at a transmission power increased by a predetermined increase step if the mobile station does not receive the acquisition indicator information.

9. The method of controlling a transmission power according to claim 1,

wherein the base station increases the transmission power of the wireless channel if a statistic value based on the transmission delay estimation information is greater than a predetermined target value.

10. The method of controlling a transmission power according to claim 1,

wherein the mobile station decides transmission power according to a reception power of a pilot signal transmitted from the base station.

11. The method of controlling a transmission power according to claim 2, further comprising a step of

causing the mobile station to reset the transmission delay estimation information if the mobile station receives the acquisition indicator information.

12. A wireless communication system for causing a base station to control a transmission power of a mobile station, comprising:

a base station including means for notifying of transmission power information on a wireless channel of an uplink, and means for changing the transmission power information on the wireless channel according to transmission delay estimation information received from the mobile station and for notifying the mobile station of the changed transmission power information on the wireless channel; and

a mobile station including means for transmitting the transmission delay estimation information on the wireless channel.

13. The wireless communication system according to claim 12, wherein the mobile station includes means for retransmitting data or a preamble after a predetermined time since transmitting the data or the preamble over the wireless channel if the mobile station does not receive, over a downlink control channel, acquisition indicator information on a notification of which the base station has received the transmitted data or preamble correctly.

14. The wireless communication system according to claim 12,

wherein the base station transmits the transmission power information over a broadcast channel for transmission to a plurality of mobile stations.

15. The wireless communication system according to claim 12,

wherein the mobile station transmits the transmission delay estimation information over the wireless channel.

16. The wireless communication system according to claim 13,

wherein the mobile station notifies of the number of the transmission or the retransmission of the data or the preamble by the transmission delay estimation information.

17. The wireless communication system according to claim 13,

wherein the mobile station notifies of a time elapsed since initial transmission of the data or the preamble by the transmission delay estimation information.

18. The wireless communication system according to claim 13,

wherein the mobile station notifies of a timing of initial transmission of the data or the preamble by the transmission delay estimation information.

19. The wireless communication system according to claim 13,

wherein the mobile station retransmits the data or the preamble at a transmission power increased by a predetermined increase step if the mobile station does not receive the acquisition indicator information.

20. The wireless communication system according to claim 12,

wherein the base station increases the transmission power of the wireless channel if a statistic value based on the transmission delay estimation information is greater than a predetermined target value.

21. The wireless communication system according to claim 13,

wherein the mobile station decides transmission power according to a reception power of a pilot signal transmitted from the base station.

22. The wireless communication system according to claim 13,

wherein the mobile station resets the transmission delay estimation information if the mobile station receives the acquisition indicator information.

23. A base station comprising:

means for notifying of transmission power information on a wireless channel of an uplink;

means for receiving transmission delay estimation information, transmitted from a mobile station, on the wireless channel; and

means for changing the transmission power information on the wireless channel according to the transmission delay estimation information and for notifying the mobile station of the changed transmission power information on the wireless channel.

24. The base station according to claim 23,

wherein the base station transmits the transmission power information over a broadcast channel for transmission to a plurality of mobile stations.

25. The base station according to claim 23,

wherein the base station increases the transmission power of the wireless channel if a statistic value based on the transmission delay estimation information is greater than a predetermined target value.

26. A mobile station comprising:

means for receiving transmission power information, transmitted from a base station, on a wireless channel of an uplink; and

means for transmitting transmission delay estimation information on the wireless channel.

27. The mobile station according to claim 26, further comprises means for retransmitting data or a preamble after a predetermined time since transmitting the data or the preamble over the wireless channel if the mobile station does not receive, over a downlink control channel, acquisition indicator information on a notification of which the base station has received the transmitted data or preamble correctly.

28. The mobile station according to claim 26,

wherein the mobile station transmits the transmission delay estimation information over the wireless channel.

29. The mobile station according to claim 26,

wherein the mobile station notifies of the number of the transmission or the retransmission of the data or the preamble by the transmission delay estimation information.

30. The mobile station according to claim 26,

wherein the mobile station notifies of a time elapsed since initial transmission of the data or the preamble by the transmission delay estimation information.

31. The mobile station according to claim 26,

wherein the mobile station notifies of a timing of initial transmission of the data or the preamble by the transmission delay estimation information.

32. The mobile station according to claim 27,

wherein the mobile station retransmits the data or the preamble at a transmission power increased by a predetermined increase step if the mobile station does not receive the acquisition indicator information.

33. The mobile station according to claim 26,

wherein the mobile station decides transmission power according to a reception power of a pilot signal transmitted from the base station.

34. The mobile station according to claim 27,

wherein the mobile station resets the transmission delay estimation information if the mobile station receives the acquisition indicator information.

35. A method of controlling a transmission power of a mobile station by a base station, comprising the steps of:

notifying of transmission power information on a wireless channel of an uplink;

receiving transmission delay estimation information, transmitted from the mobile station, on the wireless channel; and

changing the transmission power information on the wireless channel according to the transmission delay estimation information, and notifying the mobile station of the changed transmission power information on the wireless channel.

36. The method of controlling a transmission power of a mobile station according to claim 35,

wherein the transmission power information is transmitted over a broadcast channel for transmission to a plurality of mobile stations.

37. The method of controlling a transmission power of a mobile station according to claim 35,

wherein the transmission power of the wireless channel is increased if a statistic value based on the transmission delay estimation information is greater than a predetermined target value.

38. A method of controlling a transmission power of a mobile station, comprising the steps of:

causing the mobile station to receive transmission power information, transmitted from a base station, on a wireless channel of an uplink; and

causing the mobile station to transmit transmission delay estimation information on the wireless channel.

39. The method of controlling a transmission power of a mobile station according to claim 38,

causing the mobile station to retransmit data or a preamble after a predetermined time since transmitting the data or the preamble over the wireless channel if the mobile station does not receive, over a downlink control channel, acquisition indicator information on a notification of which the base station has received the transmitted data or preamble correctly.

40. The method of controlling a transmission power of a mobile station according to claim 38,

wherein the mobile station transmits the transmission delay estimation information over the wireless channel.

41. The method of controlling a transmission power of a mobile station according to claim 38,

wherein the mobile station notifies of the number of the transmission or the retransmission of the data or the preamble by the transmission delay estimation information.

42. The method of controlling a transmission power of a mobile station according to claim 38,

wherein the mobile station notifies of a time elapsed since initial transmission of the data or the preamble by the transmission delay estimation information.

43. The method of controlling a transmission power of a mobile station according to claim 38,

wherein the mobile station notifies of a timing of initial transmission of the data or the preamble by the transmission delay estimation information.

44. The method of controlling a transmission power of a mobile station according to claim 39,

wherein the mobile station retransmits the data or the preamble at a transmission power increased by a predetermined increase step if the mobile station does not receive the acquisition indicator information.

45. The method of controlling a transmission power of a mobile station according to claim 38,

wherein the mobile station decides transmission power according to a reception power of a pilot signal transmitted from the base station.

46. The method of controlling a transmission power of a mobile station according to claim 39, further comprising a step of

causing the mobile station to reset the transmission delay estimation information if the mobile station receives the acquisition indicator information.

47. A computer-readable medium having stored therein a program for controlling a base station, causing a computer to execute functions of:

notifying of transmission power information on a wireless channel of an uplink;

receiving transmission delay estimation information, transmitted from a mobile station, on the wireless channel; and

hanging the transmission power information on the wireless channel according to the transmission delay estimation information and of notifying the mobile station of the changed transmission power information on the wireless channel.

48. A computer-readable medium having stored therein a program for controlling a mobile station, causing a computer to execute functions of:

receiving transmission power information, transmitted from a base station, on a wireless channel of an uplink; and

transmitting transmission delay estimation information on the wireless channel.

49. The computer-readable medium according to claim 48,

wherein the transmission delay estimation information is transmitted over the wireless channel.