Method and apparatus to control handoff between different wireless systems

• US 20020067707A1
• Filed: 09/21/2001
• Published: 06/06/2002
• Est. Priority Date: 12/04/2000
• Status: Active Grant

• Current Assignee: Ericsson AB (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson AB (Telefonaktiebolaget LM Ericsson)
• Inventors: Higashi, Yusuke, Wu, Geng, Vasudevan, Mini, Ahmad, Azeem, Morales, Linda, Paranchych, David W.
• Granted Patent: US 7,843,878 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 36/38 by fixed network equipment

Abstract

A wireless communications network includes a first base station system that performs wireless communications according to a first protocol (e.g., 1xEV-DO protocol) and a second base station system that performs wireless communications according to a second, different protocol (e.g., IS-2000). A link is provided between the first and second base station systems to enable a network-initiated handoff procedure. If a source base station system detects that a handoff of a mobile station to a target base station system is required, the source base station system exchanges messaging over the link with the target base station system to perform the handoff. In one example, the handoff is a hard handoff.

Claims

1. A method of performing wireless communications, comprising:

communicating bearer traffic for a packet-switched communications session between a mobile station and a first base station associated with a first type of wireless system;

determining if handoff is required from the first base station to a second base station associated with a second, different type of wireless system; and

exchanging messages between the first and second base stations to perform the handoff in response to determining that the handoff is required.

2. The method of claim 1, further comprising initiating the handoff by one of the first and second base stations.

3. The method of claim 1, wherein the first base station comprises an IS-2000 base station, and wherein communicating the bearer traffic comprises communicating the bearer traffic between the mobile station and the IS-2000 base station.

4. The method of claim 3, wherein determining if handoff is required from the first base station to the second base station comprises determining if handoff is required from the IS-2000 base station to a 1xEV access network.

5. The method of claim 3, wherein determining if handoff is required from the first base station to the second base station comprises determining if handoff is required from the IS-2000 base station to a High Data Rate (HDR) access network.

6. The method of claim 1, wherein the first base station comprises a High Data Rate access network, and wherein communicating the bearer traffic comprises communicating the bearer traffic between the mobile station and the High Data Rate access network.

7. The method of claim 6, wherein determining if handoff is required from the first base station to the second base station comprises determining if handoff is required from the High Data Rate access network to an IS-2000 base station.

8. The method of claim 1, wherein the first base station comprises a 1xEV access network, and wherein communicating the bearer traffic comprises communicating the bearer traffic between the mobile station and the 1xEV access network.

9. The method of claim 8, wherein determining if handoff is required from the first base station to the second base station comprises determining if handoff is required from the 1xEV access network to an IS-2000 base station.

10. The method of claim 1, wherein exchanging the messages comprises exchanging a message indicating that a handoff is required.

11. The method of claim 1, wherein exchanging the messages comprises sending a message from the first base station to the second base station indicating that a handoff is required.

12. The method of claim 11, wherein exchanging the messages further comprises sending another message from the second base station to the first base station to initiate a handoff procedure.

13. The method of claim 12, wherein exchanging the messages further comprises sending a further message from the first base station to the second base station to indicate that the mobile station has been directed to hand off to the second base station.

14. The method of claim 1, wherein exchanging the messages comprises exchanging the messages over a link between the first base station and the second base station.

15. The method of claim 1, wherein performing the handoff comprises performing a hard handoff between the first base station and the second base station.

17. The apparatus of claim 16, wherein the controller is adapted to perform the handoff by performing a hard handoff.

18. The apparatus of claim 16, wherein the controller is adapted to communicate bearer traffic according to IS-2000 format with the mobile station.

19. The apparatus of claim 18, wherein the second base station system comprises a High Data Rate base station, and wherein the controller is adapted to exchange the messaging with the High Data Rate base station.

20. The apparatus of claim 18, wherein the second base station system comprises a 1xEV base station, and wherein the controller is adapted to exchange the messaging with the 1xEV base station.

21. The apparatus of claim 16, wherein the controller is adapted to exchange the messaging by sending a message indicating that a handoff is required.

22. The apparatus of claim 21, wherein the controller is adapted to exchange the messaging by receiving a message initiating the handoff procedure.

23. The apparatus of claim 22, wherein the controller is adapted to send a further message from the first base station system to the second base station system to indicate that the mobile station has been directed to hand off to the second base station system.

25. The article of claim 24, wherein the first base station comprises an IS-2000 base station, and wherein the instructions when executed cause the first base station system to exchange IS-2000 signaling with the mobile station.

26. The article of claim 25, wherein the instructions when executed cause the first base station system to determine if handoff is required by determining if handoff is required from the IS-2000 base station to one of a 1xEV access network and a High Data Rate (HDR) access network.

27. The article of claim 24, wherein the first base station comprises one of a High Data Rate (HDR) access network and a 1xEV access network, and wherein the instructions when executed cause the first base station system to exchange one of High Data Rate (HDR) signaling and 1xEV signaling with the mobile station.

28. The article of claim 27, wherein the instructions when executed cause the first base station system to determine if handoff is required by determining if handoff is required from the one of a High Data Rate (HDR) access network and 1xEV access network to a IS-2000 base station.

29. The article of claim 24, wherein the instructions when executed cause the first base station system to exchange the messaging by sending a message indicating that a handoff is required.

16. An apparatus associated with a first base station system that performs wireless communications according to a first protocol, the apparatus comprising:

an interface to a second base station system that performs wireless communications according to a second, different protocol; and

a controller adapted to communicate bearer traffic for a packet-switched communications session with a mobile station,

the controller adapted to further exchange messaging with the second base station system through the interface to perform a handoff of the packet-switched communications session from the first base station system to the second base station system.

24. An article comprising at least one storage medium containing instructions that when executed cause a first base station system to:

exchange signaling according to a first protocol with a mobile station to establish a packet-switched communications session between the mobile station and another endpoint;

determine if a handoff is required to a second base station system that performs wireless communications according to a second, different protocol; and

exchange messaging with the second base station system through a link between the first and second base station systems to perform the handoff.