Systems and methods for wireless communication

• US 20070274256A1
• Filed: 05/02/2007
• Published: 11/29/2007
• Est. Priority Date: 05/29/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hayase, Shigenori, Yano, Takashi, Shida, Masaaki, Ishifuji, Tomoaki, Murai, Shinji
• Granted Patent: US 8,310,995 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.

Claims

1. A wireless communication apparatus for communicating with a plurality of stations using a Space Division Multiple Access (SDMA), comprising:

a channel state information collecting unit which collects channel state information of channels between the wireless communication apparatus and the plurality of stations;

a wireless resource allocating unit which generates a plurality of SDMA group candidates as candidates for SDMA groups formed by conducting the SDMA for the plurality of stations, estimates communication performance of each of the stations belonging to the SDMA group candidates by using the channel state information, selects an SDMA group from the plurality of SDMA groups according to the communication performance estimated for each station, and determines a period of time to be allocated to the selected SDMA group to thereby allocate wireless resources to the plurality of stations; and

a signal processing unit which communicates with the plurality of stations using the wireless resources thus allocated.

2. A wireless communication apparatus according to claim 1, further comprising a require information unit which manages information of the communication performance required for each of the stations or information of communication performance required for an application provided to the station, wherein

the wireless resource allocating unit selects the SDMA groups and determines the allocation of a period of time to the SDMA group by use of the communication performance thus required.

3. A wireless communication apparatus according to claim 1, wherein the channel state information collecting unit collects, as the channel state information, a Signal to Noise power Ratio (SNR) or a Signal to Interference power Ratio (SIR).

4. A wireless communication apparatus according to claim 2, wherein the communication performance thus required includes information of channel capacity required for the station or the application or information of delay allowed therefor.

5. A wireless communication apparatus according to claim 1, wherein the wireless resource allocating unit determines the SDMA group candidates according to a correlation of the channel state information.

6. A wireless communication apparatus according to claim 1, wherein the wireless resource allocating unit selects the SDMA groups and determines the allocation of a period of time to the SDMA group by conducting an optimizing calculation in which an evaluation index is minimization of a period of time required for data communication with the plurality of stations.

7. A wireless communication apparatus according to claim 1, wherein the wireless resource allocating unit selects the SDMA groups and determines the allocation of a period of time to the SDMA group by conducting an optimizing calculation in which an evaluation index is maximization of a total of channel capacity for the plurality of stations.

8. A wireless communication apparatus according to claim 1, wherein the wireless resource allocating unit selects the SDMA groups and determines the allocation of a period of time to the SDMA group by conducting an optimizing calculation in which an evaluation index is an operation to equally allocate the channel capacity to the respective stations.

9. A wireless communication apparatus according to claim 2, wherein the wireless resource allocating unit selects the SDMA groups and determines the allocation of a period of time to the SDMA group by conducting an optimizing calculation in which if the communication performance thus required includes transmission data of absolute guarantee type and transmission data of relative guarantee type, an evaluation index is maximization of a total of channel capacity for communication of the transmission data of the relative guarantee type while satisfying a requirement of the communication performance for the transmission data of the absolute guarantee type.

10. A wireless communication apparatus according to claim 2, wherein the wireless resource allocating unit selects the SDMA groups and determines the allocation of a period of time to the SDMA group by conducting an optimizing calculation in which if the communication performance thus required includes transmission data of absolute guarantee type and transmission data of relative guarantee type, an evaluation index is an operation to equally allocate channel capacity of the transmission data of the relative guarantee type to the respective stations while satisfying a requirement of the communication performance for the transmission data of the absolute guarantee type.

11. A wireless resource allocation method for use in a wireless communication apparatus for communicating with a plurality of stations using a Space Division Multiple Access (SDMA), comprising:

a first steps of collecting channel state information of channels between the wireless communication apparatus and the plurality of stations;

a second step of generating a plurality of SDMA group candidates as candidates for SDMA groups formed by conducting the SDMA for the plurality of stations;

a third step of estimating communication performance of each of the stations belonging to the SDMA group candidates by using the channel state information, selecting an SDMA group from the plural SDMA groups according to the communication performance estimated for each of the stations, determining a period of time to be allocated to the SDMA group thus selected to thereby allocate wireless resources to the plurality of stations; and

a fourth step of communicating with the plural stations using the allocated wireless resources.

12. A wireless resource allocation method according to claim 11, further comprising a step of managing information of the communication performance required for each of the stations or information of communication performance required for an application provided to the station, wherein

the third step further comprises selecting the SDMA groups and determining the allocation of a period of time to the SDMA group by use of the communication performance thus required.

13. A wireless resource allocation method according to claim 12, further comprising a step of collecting, as the channel state information, a Signal to Noise power Ratio (SNR) or a Signal to Interference power Ratio (SIR).

14. A wireless resource allocation method according to claim 12, wherein the communication performance thus required includes information of channel capacity required for the station or the application or information of delay allowed therefor.

15. A wireless resource allocation method according to claim 12, wherein the second step further comprises determining the SDMA group candidates according to a correlation of the channel state information.

16. A wireless resource allocation method according to claim 11, wherein the third step further comprises selecting the SDMA groups and determining the allocation of a period of time to the SDMA group through an optimizing calculation in which an evaluation index is minimization of a period of time required for data communication with the plurality of stations.

17. A wireless resource allocation method according to claim 11, the third step further comprises selecting the SDMA groups and determining the allocation of a period of time to the SDMA group through an optimizing calculation in which an evaluation index is maximization of a total of channel capacity for the plurality of stations.

18. A wireless resource allocation method according to claim 11, the third step further comprises selecting the SDMA groups and determining the allocation of a period of time to the SDMA group through an optimizing calculation in which an evaluation index is an operation to equally allocate the channel capacity to the respective stations.

19. A wireless resource allocation method according to claim 12, wherein the third step further comprises selecting the SDMA groups and determining the allocation of a period of time to the SDMA group through an optimizing calculation in which if the communication performance thus required includes transmission data of absolute guarantee type and transmission data of relative guarantee type, an evaluation index is maximization of a total of channel capacity for communication of the transmission data of the relative guarantee type while satisfying a requirement of the communication performance for the transmission data of the absolute guarantee type.

20. A wireless resource allocation method according to claim 12, the third step further comprises selecting the SDMA groups and determining the allocation of a period of time to the SDMA group through an optimizing calculation in which if the communication performance thus required includes transmission data of absolute guarantee type and transmission data of relative guarantee type, an evaluation index is an operation to equally allocate channel capacity of the transmission data of the relative guarantee type to the respective stations while satisfying a requirement of the communication performance for the transmission data of the absolute guarantee type.