Handover in a radio communication system

• US 8,213,384 B2
• Filed: 04/26/2007
• Issued: 07/03/2012
• Est. Priority Date: 05/10/2006
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks GmbH & Co. KG (Nokia Corporation)
• Original Assignee: Nokia Siemens Networks GmbH & Company KG (Nokia Corporation)
• Inventors: Breuer, Volker, Lamprecht, Frank
• Primary Examiner(s): Abelson, Ronald
• Application Number:
  US12/227,177
• Publication Number:
  US 20100027505A1
• Time in Patent Office: 1,895 Days
• Field of Search: 370/331, 455438-443
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

In a method for communication by radio a first network radio station allocates radio resources to a subscriber station and communicates with the subscriber station using a portion of the radio resources. A second network radio station uses another portion of the radio resources to send a signaling signal which is intended exclusively for the subscriber station. The first network radio station and/or the second network radio station receives a message from the subscriber station, acknowledging receipt of the signaling signal. In response to the message from the subscriber station, the communication of the subscriber station is handed over from the first network radio station to the second network radio station.

Claims

1. A method of communication by radio, the method comprising:

allocating radio resources to a subscriber station from a first network-based radio station and communicating with the subscriber station using a portion of the allocated radio resources; and

sending a signalling signal intended exclusively for the subscriber station from a second network-based radio station using another portion of the radio resources, the another portion of the allocated radio resources being allocated by the first network-based radio station,

wherein the first network-based radio station and/or the second network-based radio station receives a message from the subscriber station confirming receipt of the signalling signal, the message from the subscriber station prompting a communication of the subscriber station to be handed over from the first network-based radio station to the second network-based radio station, wherein the second network-based radio station stops sending the signalling signal after the subscriber station had been handed over from the first network-based radio station to the second network-based radio station.

2. The method as claimed in claim 1, wherein the communication between the subscriber station and the first network-based radio station takes place at a same time as when the signalling signal is sent by the second network-based radio station.

3. The method as claimed in claim 1, wherein

the radio resources are a plurality of sub-bands of a frequency band.

4. The method as claimed in claim 1, wherein the signalling signal from the second network-based radio station is a synchronization signal.

5. The method as claimed in claim 4, wherein the subscriber station uses the synchronization signal to perform synchronization, thereby allowing communication between the subscriber station and the second network-based radio station.

6. The method as claimed in claim 1, wherein the handover of the subscriber station from the first network-based radio station to the second network-based radio station is immediately followed by the communication between the subscriber station and the second network-based radio station using the other portion of the radio resources.

7. The method as claimed in claim 1, wherein prior to the sending of the signalling signal, the first network-based radio station sends the second network-based radio station information concerning the other portion of the radio resources.

8. The method as claimed in claim 7, wherein the second network-based radio station starts to send the signalling signal after the second network -based radio station has received the information concerning the other portion of the radio resources.

9. The method as claimed in claim 1, wherein after the handover of the subscriber station from the first network-based radio station to the second network-based radio station, the second network-based radio station allocates to the subscriber station radio resources different than the radio resources allocated to the subscriber station from the first network-based radio station.

10. The method as claimed in claim 1, wherein prior to the allocation of the radio resources from the first network-based radio station to the subscriber station, the first network-based radio station receives a message from the subscriber station concerning the handover of the communication of the subscriber station from the first network-based radio station to the second network-based radio station.

11. The method as claimed in claim 1, wherein prior to the allocation of the radio resources from the first network-based radio station to the subscriber station, the first network-based radio station and the subscriber station communicate with one another using radio resources which are different than the radio resources allocated to the subscriber station from the first network-based radio station.

12. The method as claimed in claim 1, wherein the first network-based radio station receives the message from the subscriber station confirming receipt of the signal and sends the second network-based radio station an instruction to perform the handover.

13. The method as claimed in claim 1, wherein the second network-based radio station receives the message from the subscriber station confirming receipt of the signal and sends the first network-based radio station an instruction to perform the handover.

14. The method as claimed in claim 1, wherein the communication of the subscriber station is communication in a downlink.

15. A method of communication by radio, comprising:

receiving, at a subscriber station, information concerning an allocation of radio resources to the subscriber station from a first network-based radio station and communicating with the first network-based radio station using a portion of the radio resources;

receiving, at the subscriber station, a signalling signal intended exclusively for the subscriber station from a second network-based radio station using another portion of the allocated radio resources, the another portion of the allocated radio resources being allocated by the first network-based radio station; and

sending a message confirming receipt of the signalling signal to the first network-based radio station and/or the second network-based radio station from the subscriber station,

wherein a communication of the subscriber station is handed over from the first network-based radio station to the second network-based radio station when the signalling signal is confirmed to have been received, wherein the second network-based radio station stops sending the signalling signal after the subscriber station has been handed over from the first network-based radio station to the second network-based radio station.

16. The method as claimed in claim 15, wherein the communication between the subscriber station and the first network-based radio station takes place at a same time as when the signalling signal is sent by the second network-based radio station.

17. The method as claimed in claim 15, wherein the radio resources are a plurality of sub-bands of a frequency band.

18. The method as claimed in claim 15, wherein the signalling signal from the second network-based radio station is a synchronization signal.

19. The method as claimed in claim 18, wherein the subscriber station uses the synchronization signal to perform synchronization, thereby allowing communication between the subscriber station and the second network-based radio station.

20. The method as claimed in claim 15, wherein the handover of the subscriber station from the first network-based radio station to the second network-based radio station is immediately followed by the communication between the subscriber station and the second network-based radio station using the other portion of the radio resources.

21. The method as claimed in claim 15, wherein prior to the sending of the signalling signal, the first network-based radio station sends the second network-based radio station information concerning the other portion of the radio resources.

22. The method as claimed in claim 21, wherein the second network-based radio station starts to send the signalling signal after the second network -based radio station has received the information concerning the other portion of the radio resources.

23. The method as claimed in claim 15, wherein after the handover of the subscriber station from the first network-based radio station to the second network-based radio station, the second network-based radio station allocates to the subscriber station radio resources different than the radio resources allocated to the subscriber station from the first network-based radio station.

24. The method as claimed in claim 15, wherein prior to the allocation of the radio resources from the first network-based radio station to the subscriber station, the first network-based radio station receives a message from the subscriber station concerning the handover of the communication of the subscriber station from the first network-based radio station to the second network-based radio station.

25. The method as claimed in claim 15, wherein prior to the allocation of the radio resources from the first network-based radio station to the subscriber station, the first network-based radio station and the subscriber station communicate with one another using radio resources which are different than the radio resources allocated to the subscriber station from the first network-based radio station.

26. The method as claimed in claim 15, wherein the first network-based radio station receives the message from the subscriber station confirming receipt of the signal and sends the second network-based radio station an instruction to perform the handover.

27. The method as claimed in claim 15, wherein the second network-based radio station receives the message from the subscriber station confirming receipt of the signal and sends the first network-based radio station an instruction to perform the handover.

28. The method as claimed in claim 15, wherein the communication of the subscriber station is communication in a downlink.

29. A radio communication system having a subscriber station, comprising:

a first network-based radio station allocating radio resources to the subscriber station and communicating with the subscriber station using a portion of the radio resources;

a second network-based radio station sending a signalling signal intended exclusively for the subscriber station using another portion of the allocated radio resources, the another portion of the allocated radio resources being allocated by the first network-based radio station;

wherein the first network-based radio station and/or the second network-based radio station receive a message from the subscriber station confirming receipt of the signalling signal, the first network-based radio station and the second network-based radio station handing over a communication of the subscriber station from the first network-based radio station to the second network-based radio station upon receipt of the message from the subscriber station, wherein the second network-based radio station stops sending the signalling signal after the subscriber station has been handed over from the first network-based radio station to the second network-based radio station.