1. A method comprising:
- a serving cell receiving a request for neighbour cell system information;
- in response to the request, the serving cell transmitting neighbour cell system information.
2. The method of claim 1 wherein:
- receiving a request for neighbour cell information comprises receiving the request on an uplink control channel available to a mobile station in CS (circuit switched)-only mode; and
- transmitting neighbour cell system information comprises transmitting the neighbour cell information on a downlink control channel available to a mobile station in CS (circuit switched)-only mode.
3. The method of claim 2 wherein each control channel is a control channel that may steal speech frames to send control information.
4. The method of claim 2 wherein each control channel is a FACCH (fast associated control channel).
5. The method of claim 3 further comprising transmitting neighbour cell system information during a downlink discontinuous transmission period.
6. The method of claim 2 wherein each control channel is a SACCH (slow associated control channel).
7. The method of claim 1 wherein:
- receiving a request for neighbour cell information comprises receiving the request on an uplink packet switched control channel available to a mobile station having a packet switched connection;
- transmitting neighbour cell system information comprises transmitting the neighbour cell information on a downlink packet switched control channel available to a mobile station having a PS connection.
8. The method of claim 7 wherein each control channel is a PACCH (packet associated control channel).
9. The method of claim 1 wherein:
- the request contains an identification of at least one neighbour cell.
10. The method of claim 1 wherein the request contains an indication of which system information is being requested.
11. The method of claim 1 wherein:
- a request for neighbour cell information that does not contain an identification of at least one neighbour cell is treated as a request for system information for all of the neighbour cells.
12. The method of claim 1 wherein:
- a request for neighbour cell information that does not contain an indication of any specific system information is treated as a request for all of a predefined set of system information.
13. The method of claim 9 wherein the indication of which system information is being requested comprises a bitmap in respect of a set of defined SI blocks.
14. The method of claim 1 further comprising:
- prioritizing the neighbour cell system information transmission by transmitting system information taking into account prioritization.
15. The method of claim 1 further comprising:
- transmitting a “no change” message to indicate there is no change to previously transmitted neighbour cell system information.
16. The method of claim 1 further comprising:
- configuring a system information validity that is longer than 30 seconds at least for the transmitted neighbour cell system information.
17. The method of claim 1 further comprising:
- transmitting an indication of support for responding to the request for neighbour cell system information.
18. A method in a mobile station, the method comprising:
- transmitting a request for neighbour cell system information;
- in response to the request, receiving neighbour cell system information.
19. The method of claim 18 wherein:
- transmitting a request for neighbour cell information comprises transmitting the request on an uplink control channel available to the mobile station in CS (circuit switched)-only mode; and
- receiving neighbour cell system information comprises receiving the neighbour cell information on a downlink control channel available to the mobile station in CS (circuit switched)-only mode.
20. The method of claim 19 wherein each control channel is a control channel that steals speech frames to send control information.
