Granted Patent B1

US 7,953,411 · App. 11/150,829 · Granted May 31, 2011

Abstract

Claims (34)

1. A method for implementing a hand over of a mobile subscriber station (MSS) in a wireless communication network, comprising:

operating the MSS that is serviced by a current base station of a plurality of adjacent base stations to monitor air interface messages from the plurality of adjacent base stations;

controlling the MSS to transmit data to and receive data from only the current base station in one or more bursts that are allocated for the MSS in each single frame while simultaneously operating the MSS to monitor air interface messages from the plurality of adjacent base stations including the current base station, wherein the data comprises communication traffic between the MSS and the current base station, wherein the current base station is the only base station of the plurality of adjacent base stations operated to transmit data to the MSS using the one or more bursts that are allocated for the MSS in the each single frame;

operating the MSS to identify a preferred base station of the plurality of adjacent base stations to replace the current base station based on the monitored air interface messages;

receiving a request from the MSS to hand over the MSS from the current base station to the preferred base station for the MSS to transmit data to and receive data from the preferred base station subsequent to the handing over; and

in response to receiving the request, changing the base station that services the MSS from the current base station to the preferred base station,

wherein the MSS is operated to select the preferred base station based on carrier to interference plus noise ratio (CINR) values received from the plurality of adjacent base stations, and

wherein changing the base station that services the MSS from the current base station to the preferred base station further comprises:

transmitting a signal to the current base station identifying the preferred base station;

stopping the MSS from transmitting data to and receiving data from the current base station; and

operating the MSS to exchange transmission of data at a subsequent frame with the preferred base station.

2. The method of claim 1 , the messages include DL_MAP and UL_MAP messages.

3. The method of claim 1 , wherein the signal is transmitted to the current base station by a fast feedback channel.

4. The method of claim 1 , wherein the wireless communication network is an orthogonal frequency division multiplexing (OFDM) wireless communication network.

5. The method of claim 1 , wherein the wireless communication network is an orthogonal frequency division multiple access (OFDMA) wireless communication network.

6. The method of claim 1 , further comprising maintaining, at the current base station, an active set comprising a list of the plurality of adjacent base stations.

7. The method of claim 1 , wherein the current base station and the preferred base station operate at a same frequency channel.

8. The method of claim 1 , wherein the current base station and the preferred base station have synchronized frames.

9. The method of claim 1 , wherein the current base station and the preferred base station share MAC context.

10. A method for implementing a hand over of a mobile subscriber station (MSS) in a wireless communication network, comprising:

maintaining an active set comprising a list of transmitting base stations, each transmitting base station capable of communicating with the MSS, the MSS communicating with only one current transmitting base station in a single frame;

monitoring all transmitting base stations in the active set while transmitting data to and receiving data from the current transmitting base station in one or more bursts that are allocated for the MSS in the single frame, the data representing communication traffic between the MSS and the current transmitting base station, wherein the current transmitting base station is the only base station of the list of transmitting base stations operated to transmit data to the MSS using the one or more bursts that are allocated for the MSS in the single frame;

determining a preferred transmitting base station included in the transmitting base stations based upon the monitoring;

informing the preferred transmitting base station to the current transmitting base station by a fast feedback channel;

stopping the MSS from transmitting data to and receiving data from the current transmitting base station; and

operating the MSS to exchange transmission of data at a subsequent frame with the preferred base station.

11. The method of claim 10 , wherein the active set is maintained in the MSS and the current transmitting base station.

12. The method of claim 10 , wherein determining the preferred transmitting base station is based on received carrier to interference plus noise ratio (CINR) values from the transmitting base stations included in the list.

13. The method of claim 10 , further comprising completing any activated hybrid automatic repeat requests (H-ARQ) prior to switching from the current transmitting base station to the preferred transmitting base station.

14. The method of claim 10 , wherein the wireless communication network is an orthogonal frequency division multiplexing (OFDM) wireless communication network.

15. The method of claim 10 , wherein the wireless communication network is an orthogonal frequency division multiple access (OFDMA) wireless communication network.

16. The method of claim 10 , wherein the current transmitting base station and the preferred transmitting base station operate at a same frequency channel.

17. The method of claim 10 , wherein the current transmitting base station and the preferred transmitting base station have synchronized frames.

18. The method of claim 10 , wherein the current transmitting base station and the preferred transmitting base station share MAC context.

Assignments (8)