Subject: Mobile Computing

Difficulty: Medium

Marks: 4 Marks

Types of Channel Assignment strategies:

1) Fixed channel assignment

2) Dynamic channel assignment

Fixed channel assignment

• Each cell is allocated a predetermined set of voice channel
• Any new call attempt can only be served by the unused channels in the cell.
• The call will be blocked if all channels in that cell are occupied
• Borrowing strategy is a type of fixed channel assignment strategy.
• In this the cell is allowed to borrow channels from neighboring cell if all of its own channels are already occupied.
• The MSC (Mobile switching center) supervises such borrowing procedures and ensures that borrowing of a channel does not disrupt or interfere with any of the calls in progress in the donor cell

Dynamic channel assignment

• Channels are not allocated to cells permanently.
• Mobile Switching center (MSC) allocates channels based on request.
• Reduce the likelihood of blocking, increase capacity.
• This requires the MSC to collect real time data on channel occupancy, traffic distribution &Radio Signal strength Indications (RSSI) of all channels on a continuous basis.