System and method for reallocating a traffic channel in soft handoff state

• US 7,299,052 B2
• Filed: 09/22/2003
• Issued: 11/20/2007
• Est. Priority Date: 11/09/1998
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lovette, Steven E., Ji, Li
• Primary Examiner(s): Feild; Joseph
• Assistant Examiner(s): DOAN, PHUOC HUU
• Application Number:
  US10/667,052
• Publication Number:
  US 20040081080A1
• Time in Patent Office: 1,520 Days
• Field of Search: 455/452.1, 455/512, 455/450, 455/442, 455/439, 455/436, 455/451
• US Class Current: 455/452.1
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 76/30 Connection release

Abstract

There is disclosed, for use in a CDMA wireless network, a channel resource allocator for reallocating a data traffic channel in a soft handoff state to handle incoming calls from new mobile stations. The channel resource allocator includes an overhead channel controller for reconfiguring a data traffic channel as an overhead channel upon failure of an overhead channel element in a base transceiver station (BTS). The channel resource allocator determines if all data traffic channels of the BTS are in use. If so, the channel resource allocator determines whether any of the existing calls being serviced by the data traffic channels are in a soft handoff state in which the call is connected simultaneously to two or more base transceiver stations. If so, the channel resource allocator drops the connection to the BTS in which the overhead channel failure occurred, thereby freeing up the data traffic channel. The overhead channel controller may then reconfigure the dropped data traffic channel as an overhead channel, or the channel resource allocator may reallocate the dropped data traffic channel to handle a new incoming call from a mobile station.

Claims

1. For use in a wireless network comprising a first base transceiver station capable of establishing and maintaining communication links with a plurality of mobile stations by means of a plurality of data traffic channels, an apparatus for allocating said plurality of data traffic channels comprising:

an access request detection circuit capable of detecting an access request message received from an accessing one of said plurality of mobile stations and generating an access request notification; and

a channel allocator capable of receiving said access request notification and, in response thereto;

     1) terminating a first communication link between said first base transceiver station and a first selected one of said plurality of mobile stations, wherein said first selected mobile station maintains at least a second communication link with at least a second base transceiver station of said wireless network, and

     2) allocating a first data traffic channel associated with said terminated first communication link to establish a communication link with said accessing mobile station.

2. The apparatus as set forth in claim 1 wherein said channel allocator is capable of determining if one of said plurality of data traffic channels associated with said first base transceiver station is unused prior to terminating said first communication link between said first base transceiver station and said first selected mobile station.

3. The apparatus as set forth in claim 2 wherein said channel allocator allocates an unused one of said plurality of data traffic channels associated with said first base transceiver station to establish a communication link with said accessing mobile station in lieu of terminating said first communication link and allocating said first data traffic channel associated with said terminated first communication link to establish a communication link with said accessing mobile station.

4. The apparatus as set forth in claim 1 further comprising a memory coupled to said channel allocator, wherein said memory is capable of storing status data associated with said plurality of communication links maintained by said first base transceiver station with said plurality of a mobile stations.

5. The apparatus as set forth in claim 4 wherein said status data comprises a received signal strength indicator associated with each of said plurality of communication links.

6. The apparatus as set forth in claim 5 wherein said status data comprises handoff state data indicating whether each mobile station associated with each of said communication links maintains communication links with at least two base transceiver stations.

7. The apparatus as set forth in claim 6 wherein said channel allocator determines a weakest received signal strength indicator associated with one of said plurality of mobile stations maintaining communication links with at least two base transceiver stations.

8. The apparatus as set forth in claim 7 wherein said channel allocator selects said communication link associated with said weakest received signal strength indicator to be said terminated first communication link.

9. A wireless network comprising:

a plurality of base transceiver stations, wherein each of said plurality of base transceiver stations is capable of establishing and maintaining a plurality of communication links with a plurality of mobile stations by means of a plurality of data traffic channels; and

an apparatus associated with a first one of said base transceiver station for allocating said plurality of data traffic channels associated with said first base transceiver station, said apparatus comprising;

an access request detection circuit capable of detecting an access request message received from an accessing one of said plurality of mobile stations and generating an access request notification; and

a channel allocator capable of receiving said access request notification and, in response thereto;

     1) terminating a first communication link between said first base transceiver station and a first selected one of said plurality of mobile stations, wherein said first selected mobile station maintains at least a second communication link with at least a second base transceiver station of said wireless network, and

     2) allocating a first data traffic channel associated with said terminated first communication link to establish a communication link with said accessing mobile station.

10. The wireless network as set forth in claim 9 wherein said channel allocator is capable of determining if one of said plurality of data traffic channels associated with said first base transceiver station is unused prior to terminating said first communication link between said first base transceiver station and said first selected mobile station.

11. The wireless network as set forth in claim 10 wherein said channel allocator allocates an unused one of said plurality of data traffic channels associated with said first base transceiver station to establish a communication link with said accessing mobile station in lieu of terminating said first communication link and allocating said first data traffic channel associated with said terminated first communication link to establish a communication link with said accessing mobile station.

12. The wireless network as set forth in claim 9 further comprising a memory coupled to said channel allocator, wherein said memory is capable of storing status data associated with said plurality of communication links maintained by said first base transceiver station with said plurality of a mobile stations.

13. The wireless network as set forth in claim 12 wherein said status data comprises a received signal strength indicator associated with each of said plurality of communication links.

14. The wireless network as set forth in claim 13 wherein said status data comprises handoff state data indicating whether each mobile station associated with each of said communication links maintains communication links with at least two base transceiver stations.

15. The wireless network as set forth in claim 14 wherein said channel allocator determines a weakest received signal strength indicator associated with one of said plurality of mobile stations maintaining communication links with at least two base transceiver stations.

16. The wireless network as set forth in claim 15 wherein said channel allocator selects said communication link associated with said weakest received signal strength indicator to be said terminated first communication link.

17. For use in a wireless network comprising a first base transceiver station capable of establishing and maintaining a plurality of communication links with a plurality of mobile stations by means of a plurality of data traffic channels, a method for allocating the plurality of data traffic channels comprising the steps of:

detecting an access request message received from an accessing one of said plurality of mobile stations;

in response to the access request message detection, terminating a first communication link between the first base transceiver station and a first selected one of the plurality of mobile stations, wherein the first selected mobile station maintains at least a second communication link with at least a second base transceiver station; and

allocating a first data traffic channel associated with the terminated first communication link to establish a communication link with the accessing mobile station.

18. The method set forth in claim 17 further comprising the step of determining if one of the plurality of data traffic channels associated with the first base transceiver station is unused prior to terminating the first communication link between the first base transceiver station and the first selected mobile station.

19. The method set forth in claim 18 further comprising the step of allocating an unused one of the plurality of data traffic channels associated with the first base transceiver station to establish a communication link with the accessing mobile station in lieu of terminating the first communication link and allocating the first data traffic channel associated with the terminated first communication link to establish a communication link with the accessing mobile station.

20. The method as set forth in claim 17 further comprising the steps of:

determining a weakest received signal strength indicator associated with one of a plurality of mobile stations maintaining communication links with the first base transceiver station and at least one other base transceiver station; and

selecting the communication link associated with the weakest received signal strength indicator to be the terminated first communication link.