Subject: Mobile Computing

Difficulty: Medium

Marks: 4 Marks

When a PSTN subscriber calls a mobile station the following sequence of events takes place:

1) The Gateway MSC recevies the call and queries the HLR for the information needed to route the call to the serving MSC/ VLR.

2) The GMSC routes the call to the MSC/VLR

3) The MSC checks the VLR for the location area of the MS.

4) The MSC contacts the MS via the BSC throug a broadcast message i.e. paging request.

5) The MS responds to the page request.

6) The BSC allocates a traffic channel and sends a message to the MS to tune to the channel. The MS generates a ringing singal and the subsriber answers, the Speech connection is established.

7) Handover,if required takes place.