Method for cell switching in wireless communication systems

• US 20030169705A1
• Filed: 03/05/2002
• Published: 09/11/2003
• Est. Priority Date: 03/05/2002
• Status: Active Grant

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Zhang, Wenfeng, Yang, Yunsong, Vasudevan, Subramanian, Knisely, Douglas N.
• Granted Patent: US 7,251,228 B2
• Time in Patent Office: Days
• US Class Current: 370/332
• CPC Class Codes: H04W 36/0085 Hand-off measurements

Abstract

A method for switching cells by a mobile equipment of a communication system. The mobile transmits a signal coded with a spreading code indicating the mobile'"'"'s intent to switch cells and the coded information also identifies to which cell the mobile wants to switch. The coded information contains channel measurement adjustment information that is continuously transmitted to the cell which is currently serving the mobile. The flow of channel measurement adjustment information is therefore not disturbed by the application of the method of the present invention. Because the coded information identifies the target cell and indicates the mobile'"'"'s intent to perform a cell switching procedure, the amount of processing done by the cells is significantly reduced thus increasing the likelihood of a successful switching procedure.

Claims

1. A method of cell switching by system equipment of a wireless communication system, the method comprising the step of:

determining, by the system equipment, whether received information is coded information indicating a mobile'"'"'s intent to switch from a serving system equipment to a particular target system equipment identified by the received information that contains channel measurement update information for the serving system equipment.

2. The method of claim 1 where the information is received over a reverse link signaling channel of a cell in which the system equipment is located.

3. The method of claim 1 further comprising the steps of:

confirming that the received information is coded information; and

transmitting, upon confirmation of the coded information, an acknowledgement signal to the mobile when the system equipment is currently serving the mobile, or

when the system equipment is a target system equipment, serving the mobile in accordance with a protocol being followed by the communication system thus allowing the mobile, the serving system equipment and the target system equipment to complete the cell switching.

4. The method of claim 1 where the coded information is a signal to which a spreading code is applied which signal contains formatted information having channel measurement adjustment information for the serving system equipment where either the spreading code or at least a portion of the formatted information identifies the particular target system equipment.

5. The method of claim 4 where the spreading code is a null code.

6. The method of claim 5 where the null code is a cover code defined by a 1×

-EVDV CDMA system and where the formatted information is a 20 millisecond framed divided into 16 substantially equal time slots one of which contains C/I information of a forward channel of the serving system equipment, three of which contain information identifying the target system equipment and twelve of which contain channel measurement adjustment information for the serving system equipment.

7. The method of claim 4 where the spreading code is a cover code.

8. The method of claim 7 where the cover code identifies the target system equipment and the formatted information is a 20 millisecond frame divided into 16 substantially equal time slots 15 of which contain channel measurement adjustment information for the serving system equipment and one of which contains C/I information for the serving system equipment.

9. The method of claim 1 where the coded information is a signal containing formatted information that identify the particular target system equipment and said formatted information also contains channel measurement adjustment information for the serving system equipment.

10. The method of claim 9 where the formatted information is a 20 millisecond framed divided into 16 substantially equal slots three of which contain information identifying the target system equipment, one of which contains C/I information for the serving system equipment and 12 of which contain channel measurement adjustment information for the serving system equipment.

20. The method of claim 9 where the formatted information is a 20 millisecond framed divided into 16 substantially equal slots three of which contain information identifying the target system equipment, one of which contains C/I information for the serving system equipment and 12 of which contain channel measurement adjustment information for the serving system equipment.

11. A method of cell switching by mobile equipment of a wireless communication system, the method comprising the step of:

transmitting, by the mobile, coded information that indicate the mobile'"'"'s intent to switch from its serving system equipment to a target system equipment identified by the coded information that contains channel measurement adjustment information for the serving system equipment.

12. The method of claim 11 where the information is transmitted over a reverse link signaling channel of a cell in which the system equipment is located.

13. The method of claim 11 further comprising the steps of:

waiting for an acknowledgement signal from the serving system equipment; and

completing the cell switching with the serving system equipment and the target system equipment.

14. The method of claim 11 where the coded information is a signal to which a spreading code is applied which signal contains formatted information having channel measurement adjustment information for the serving system equipment where either the spreading code or at least a portion of the formatted information identifies the particular target system equipment.

15. The method of claim 14 where the spreading code is a null code.

16. The method of claim 15 where the null code is a cover code defined by a 1×

-EVDV CDMA system and where the formatted information is a 20 millisecond framed divided into 16 substantially equal time slots one of which contains C/I information of a forward channel of the serving system equipment, three of which contain information identifying the target system equipment and twelve of which contain channel measurement adjustment information for the serving system equipment.

17. The method of claim 14 where the spreading code is a cover code.

18. The method of claim 17 where the cover code identifies the target system equipment and the formatted information is a 20 millisecond frame divided into 16 substantially equal time slots 15 of which contain channel measurement adjustment information for the serving system equipment and one of which contains C/I information for the serving system equipment.

19. The method of claim 11 where the coded information is a signal containing formatted information that identify the particular target system equipment and said formatted information also contains channel measurement adjustment information for the serving system equipment.