Methods and apparatus for inter-BSC soft handoff
A method for performing a soft handoff, including establishing a first control channel via a network between a first BSC and a first BTS. The method also includes establishing a second control channel via the network between a second BSC and a second BTS. A call between a mobile station (MS) and the first BTS is established, and while the call continues an indication is sent to the first BSC that the MS has received a signal from the second BTS. In response to the indication, a trigger is conveyed from the first BSC to the second BTS, and, in response to receiving the trigger at the second BTS, further traffic associated with the call is directed between the MS, the second BTS, and the first BSC, without conveying the further traffic through the second BSC.
1. A method for performing a soft handoff, comprising:
establishing a first control channel link via a network between a first base station controller (BSC) and a first base transceiver station (BTS), the first control channel link enabling the first BSC to control operation of the first BTS;
establishing a second control channel link via the network between a second BSC and a second BTS, the second control channel link enabling the second BSC to control operation of the second BTS;
establishing a call in the system under control of the first BSC;
while continuing to conduct the call, conveying an indication to the first BSC that a mobile station (MS) has received a signal from the second BTS;
in response to the indication, conveying a call transfer control trigger from the first BSC to the second BTS via the network; and
in response to receiving the call transfer control trigger at the second BTS, directing further traffic associated with the call between the MS, the second BTS, and the first BSC, without conveying the further traffic through the second BSC.
2. The method according to claim 1 , wherein establishing the first control channel link comprises establishing a first reliable connection between the first BSC and the first BTS, and using the first reliable connection for the first control link, and wherein establishing the second control channel link comprises establishing a second reliable connection between the second BSC and the second BTS, and using the second reliable connection for the second control link.
3. The method according to claim 1 , wherein the signal received from the second BTS comprises a pilot signal.
4. The method according to claim 1 , and comprising establishing a connection in the network between the first BSC and the second BTS, and wherein conveying the call transfer control trigger comprises conveying the trigger via the connection.
5. The method according to claim 4 , wherein the connection comprises a reliable connection.
6. The method according to claim 1 , wherein the network comprises a packet switching network operating under an Internet Protocol.
7. The method according to claim 1 , and comprising generating an optimum signal for the call from the further traffic and from traffic associated with the call that is conveyed between the MS, the first BTS, and the first BSC.
8. The method according to claim 1 , and comprising: establishing a third control channel link via the network between the first BSC and a third BTS, the third control channel link enabling the first BSC to control operation of the third BTS; establishing a further call in the system between the MS and the first BTS; while continuing to conduct the further call, conveying a further indication to the first BSC that the MS has received a signal from the third BTS; and in response to the further indication, directing further traffic associated with the further call between the MS, the third BTS, and the first BSC.
9. The method according to claim 1 , wherein establishing the call comprises conveying traffic and the further traffic associated with the call using a connectionless protocol.
10. Apparatus for performing a soft handoff, comprising:
a first base transceiver station (BTS);
a first base station controller (BSC) which is adapted to establish a first control channel link via a network between the first BTS and the first BSC, the first control channel link enabling the first BSC to control operation of the first BTS;
a second BTS;
a second BSC which is adapted to establish a second control channel link via the network between the second BTS and the second BSC, the second control channel link enabling the second BSC to control operation of the second BTS;
wherein the first BSC, in response to an indication to the first BSC that a mobile station (MS) has received a signal from the second BTS, is adapted to convey a call transfer control trigger from the first BSC to the second BTS via the network, and wherein the second BTS, in response to receiving the call transfer control trigger, is adapted to direct further traffic associated with the call between the MS, the second BTS, and the first BSC, without conveying the farther traffic through the second BSC.
11. The apparatus according to claim 10 , wherein establishing the first control channel link comprises establishing a first reliable connection between the first BSC and the first BTS, and using the first reliable connection for the first control link, and wherein establishing the second control channel link comprises establishing a second reliable connection between the second BSC and the second BTS, and using the second reliable connection for the second control link.
12. The apparatus according to claim 10 , wherein the signal received from the second BTS comprises a pilot signal.
13. The apparatus according to claim 10 , wherein the first BSC is adapted to establish a connection in the network between the first BSC and the second BTS, and wherein conveying the call transfer control trigger comprises conveying the trigger via the connection.
14. The apparatus according to claim 13 , wherein the connection comprises a reliable connection.
15. The apparatus according to claim 10 , wherein the network comprises a packet switching network operating under an Internet Protocol.
16. The apparatus according to claim 10 , wherein the first BSC is adapted to generate an optimum signal for the call from the further traffic and from traffic associated with the call that is conveyed between the MS, the first BTS, and the first BSC.
17. The apparatus according to claim 10 , wherein the first BSC is adapted to establish a third control channel link via the network between the first BSC and a third BTS, the third control channel link enabling the first BSC to control operation of the third BTS, and wherein the MS is adapted to establish a further call in the system between the MS and the first BTS, and, while continuing to conduct the further call, to convey a further indication to the first BSC that the MS has received a signal from the third BTS, and wherein the first BSC, in response to the further indication, is adapted to direct further traffic associated with the further call between the MS, the third BTS and the first BSC.
18. The apparatus according to claim 10 , wherein establishing the call comprises conveying traffic and the further traffic associated with the call using a connectionless protocol.
19. An apparatus for performing a soft handoff, comprising:
means for establishing a first control channel link via a network between a first base station controller (BSC) and a first base transceiver station (BTS), the first control channel link enabling the first BSC to control operation of the first BTS;
means for establishing a second control channel link via the network between a second BSC and a second BTS, the second control channel link enabling the second BSC to control operation of the second BTS; means for establishing a call in the system under control of the first BSC;
while continuing to conduct the call, means for conveying an indication to the first BSC that a mobile station (MS) has received a signal from the second BTS;
in response to the indication, means for conveying a call transfer control trigger from the first BSC to the second BTS via the network; and
in response to receiving the call transfer control trigger at the second BTS, means for directing further traffic associated with the call between the MS, the second BTS, and the first BSC, without conveying the further traffic through the second BSC.
20. The apparatus according to claim 19 , wherein means for establishing the first control channel link comprises means for establishing a first reliable connection between the first BSC and the first BTS, and using the first reliable connection for the first control link, and wherein means for establishing the second control channel link comprises means for establishing a second reliable connection between the second BSC and the second BTS, and means for using the second reliable connection for the second control link.
21. The apparatus according to claim 19 , wherein the signal received from the second BTS comprises a pilot signal.
22. The apparatus according to claim 19 , and comprising means for establishing a connection in the network between the first BSC and the second BTS, and wherein means for conveying the call transfer control trigger comprises means for conveying the trigger via the connection.
23. The apparatus according to claim 22 , wherein the connection comprises a reliable connection.
24. The apparatus according to claim 19 , wherein the network comprises a packet switching network operating under an Internet Protocol.
25. The apparatus according to claim 19 , and comprising means for generating an optimum signal for the call from the further traffic and from traffic associated with the call that is conveyed between the MS, the first BTS, and the first BSC.
26. The apparatus according to claim 19 , and comprising: means for establishing a third control channel link via the network between the first BSC and a third BTS, the third control channel link enabling the first BSC to control operation of the third BTS; means for establishing a further call in the system between the MS and the first BTS; while continuing to conduct the further call, means for conveying a further indication to the first BSC that the MS has received a signal from the third BTS; and in response to the further indication, means for directing further traffic associated with the further call between the MS, the third BTS, and the first BSC.
27. The apparatus according to claim 19 , wherein means for establishing the call comprises means for conveying traffic and the further traffic associated with the call using a connectionless protocol.