COMMUNICATION SYSTEM, METHOD FOR THE SAME AND MOBILE STATION AND BASE STATION USED FOR THE SAME

• US 20070293230A1
• Filed: 05/25/2007
• Published: 12/20/2007
• Est. Priority Date: 06/14/2006
• Status: Active Grant

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Lee, Jinsock
• Granted Patent: US 9,008,679 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

The present invention enables a high load to a mobile station and an uplink overhead to be reduced when a CQI measurement of a PRB needed for scheduling or adaptive modulation is informed of. At a base station, a set of PRBs (an active set) for which the measurements of CQIs are to be informed of is decided for each mobile station. Each mobile station measures only CQIs of the PRBs that form the active set designated by the base station and informs the base station of the measurements. That can reduce the load on the mobile station and also reduce the amount of information for informing the CQIs, thus, the uplink overhead can be also reduced.

Claims

1. A communication system in which a mobile station measures a communication channel quality of a band obtained by dividing a downlink communication band into a plurality of bands and informs a base station of the measurement via an uplink, wherein said base station comprises:

set managing means for allocating a set of bands for requiring information on the communication channel quality to said mobile station.

2. The communication system according to claim 1, wherein

said mobile station comprises:

means for measuring a communication channel quality of each band that forms said set and informs said base station of the measurement.

3. The communication system according to claim 1, wherein

said set managing means manages a band that forms said set based on predetermined frequency planning between adjacent base stations.

4. The communication system according to claim 3, wherein

said set managing means changes a band that forms said set based on a request to change said set from said mobile station.

5. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to add a band other than that forms the current set to said current set, if an interference level of the band is an interference level lower than an average interference level in said current set.

6. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to add a band other than that forms the current set to said current set, if an interference level of the band is lower than a level lower than a maximum interference level or an average interference level in the current set by a predetermined level.

7. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to add a band other than that forms the current set to said current set, if a SIR level of the band is higher than a level lower than a maximum SIR level or an average SIR level in said current set by a predetermined level.

8. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to add a band other than that forms the current set to said current set, if an interference level (or a SIR level) of the band is lower (or higher) than a predetermined interference level (or a predetermined SIR level).

9. The communication system according to claim 5, wherein

a band that can be requested to be added to said set is a band within a predetermined range.

10. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to delete a band in the current set from said current set, if an interference level of the band is higher than the interference level other than said current set.

11. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to delete a band in the current set from said current set, if an interference level of the band is higher than a level lower than a maximum interference level or an average interference level in said current set by a predetermined level.

12. The communication system according to claim 4, wherein

said mobile station comprises:

means for requesting to delete a band in the current set from said current set, if a SIR level of the band is lower than a level lower than a maximum SIR level or an average SIR level in said current set by a predetermined level.

13. The communication system according to claim 4, wherein

the mobile station comprises:

means for requesting to delete a band in the current set from said current set, if an interference level (or a SIR level) of the band is higher (or lower) than a predetermined interference level (or a predetermined SIR level).

14. The communication system according to claim 4, wherein

said set managing means deletes a band in the current set from said current set, if a pilot signal of the band is at a lower level than the level lower than the maximum pilot signal in said current set by a predetermined level.

15. A communication method in which a mobile station measures a communication channel quality of a band obtained by dividing a downlink communication band into a plurality of bands and informs a base station of the measurement via an uplink, comprising:

in said base station,

a set managing step of allocating a set of bands for requiring information on the communication channel quality to said mobile station.

16. The communication method according to claim 15, further comprising:

in said mobile station,

a step of measuring a communication channel quality of each band that forms said set and informing said base station on the measurement.

17. The communication method according to claim 15, wherein

said set managing step manages a band that forms said set based on predetermined frequency planning between adjacent base stations.

18. The communication method according to claim 17, wherein

said set managing step changes a band that forms said set based on a request to change said set from said mobile station.

19. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to add a band other than that forms the current set to said current set, if an interference level of the band is an interference level lower than an average interference level in said current set.

20. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to add a band other than that forms the current set to said current set, if an interference level of the band is lower than a level lower than a maximum interference level or an average interference level in said current set by a predetermined level.

21. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to add a band other than that forms the current set to said current set, if a SIR level of the band is higher than a level lower than a maximum SIR level or an average SIR level in said current set by a predetermined level.

22. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to add a band other than that forms the current set to said current set, if an interference level (or a SIR level) of the band is lower (or higher) than a predetermined interference level (or a predetermined SIR level).

23. The communication method according to claim 18, wherein

a band that can be requested to be added to said set is a band within a predetermined range.

24. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to delete a band in the current set from said current set, if an interference level of the band is higher than the interference level other than said current set.

25. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to delete a band in the current set from said current set, if an interference level of the band is higher than a level lower than a maximum interference level or an average interference level in said current set by a predetermined level.

26. The communication method according to claim 18, further comprising:

in said mobile station,

a step of requesting to delete a band in the current set from said current set, if a SIR level of the band is lower than a level lower than a maximum SIR level or an average SIR level in said current set by a predetermined level.

27. The communication method according to claim 18, further comprising:

in the mobile station,

a step of requesting to delete a band in the current set from said current set, if an interference level (or a SIR level) of the band is higher (or lower) than a predetermined interference level (or a predetermined SIR level).

28. The communication method according to claim 18, wherein

said set managing step deletes a band in the current set from said current set, if a pilot signal of the band is at a lower level than the level lower than the maximum pilot signal in said current set by a predetermined level.

29. A base station which is used in a mobile communication system in which a mobile station measures a communication channel quality of a band obtained by dividing a downlink communication band into a plurality of bands and informs said base station of the measurement via an uplink, comprising:

receiving means for receiving said measurement, and

set managing means for allocating a set of bands for requiring information on the communication channel quality to the mobile station.

30. The base station according to claim 29, wherein

said set managing means manages a band that forms said set based on predetermined frequency planning between adjacent base stations.

31. The base station according to claim 30, wherein

said set managing means changes a band that forms said set based on a request to change said set from said mobile station.

32. The base station according to claim 29, wherein

said set managing means deletes a band in the current set from said current set, if a pilot signal of said current band is at a lower level than the level lower than the maximum pilot signal in said current set by a predetermined level.

33. A mobile station for measuring a communication channel quality of a band obtained by dividing a downlink communication band into a plurality of bands and informing a base station of the measurement via an uplink, comprising:

means for measuring the communication channel quality of each band that forms a set of bands which is allocated by said base station and required to inform on the communication channel quality and informing said base station of the measurement.

34. The mobile station according to claim 33, comprising:

means for requesting the base station to add a band other than that forms the current set to said current set, if an interference level of the band has an interference level lower than an average interference level in said current set.

35. The mobile station according to claim 33, comprising:

means for requesting the base station to add a band other than that forms the current set to said current set, if an interference level of the band is lower than a level lower than a maximum interference level or an average interference level in said current set by a predetermined level.

36. The mobile station according to claim 33, comprising:

means for requesting the base station to add a band other than that forms the current set to said current set, if a SIR level of the band is higher than a level lower than a maximum SIR level or an average SIR level in said current set by a predetermined level.

37. The mobile station according to claim 33, comprising:

means for requesting the base station to add a band other than that forms the current set to said current set, if an interference level (or a SIR level) of the band is lower (or higher) than a predetermined interference level (or a predetermined SIR level).

38. The mobile station according to claim 34, wherein

a band that can be requested to be added to said current set is a band within a predetermined range.

39. The mobile station according to claim 33, comprising:

means for requesting the base station to delete a band in the current set from said current set, if an interference level of the band is higher than the interference level other than said current set.

40. The mobile station according to claim 33, comprising:

means for requesting the base station to delete a band in the current set from said current set, if an interference level of the band is higher than a level lower than a maximum interference level or an average interference level in said current set by a predetermined level.

41. The mobile station according to claim 33, comprising:

means for requesting the base station to delete a band in the current set from said current set, if a SIR level of the band is lower than a level lower than a maximum SIR level or an average SIR level in said current set by a predetermined level.

42. The mobile station according to claim 33, comprising:

means for requesting to delete a band in the current set from said current set, if an interference level (or a SIR level) of the band is higher (or lower) than a predetermined interference level (or a predetermined SIR level).

43. A program for causing a computer to execute operations of a base station which is used in a mobile communication system in which a mobile station measures a communication channel quality of a band obtained by dividing a downlink communication band into a plurality of bands and informs said base station of the measurement via an uplink, comprising:

process of receiving said measurement, and

process of allocating a set of bands for requiring information on the communication channel quality to said mobile station.

44. A program for causing a computer to execute mobile station'"'"'s operations of measuring a communication channel quality of a band obtained by dividing a downlink communication band into a plurality of bands and informing a base station on the measurement via an uplink, comprising:

process of measuring the communication channel quality of each band that forms a set of the bands which is allocated by the base station and is required to be informed on the communication channel quality and informing said base station of the measurement.