What do you understand by non-fixed channel assignment? Describe the corresponding algorithms.

Non Fixed Channel Assignment Algorithms:

1. Fixed Channel Algorithm: The fixed channel assignment (FCA) algorithm is the most common algorithm adopted in many cellular systems. In this algorithm, each cell assigns its own radio channels to the vehicles within its cell.

2. Dynamic Channel Assignment: In dynamic channel assignment (DCA), no fixed channels are assigned to each cell. Therefore, any channel in a composite of N radio channels can be assigned to the mobile unit. This means that a channel is assigned directly to a mobile unit. On the basis of overall system performance, DCA can also be used during a call.

3. Hybrid Channel Assignment: Hybrid channel assignment (HCA) is a combination of FCA and DCA. A portion of the total frequency channels will use FCA and the rest will use DCA.

4. Borrowing Channel Assignment: Borrowing channel assignment (BCA) uses FCA as a normal assignment condition. When all the fixed channels are occupied, then the cell borrows channels from the neighbouring cells.

5. Forcible-Borrowing Channel Assignment: In forcible-borrowing channel assignment (FBCA), if a channel is in operation and the situation warrants it, channels must be borrowed from the neighbouring cells and at the same time, another voice channel will be assigned to continue the call in the neighbouring cell. There are many different ways of implementing FBCA. In a general sense, FBCA can also be applied while accounting for the forcible borrowing of the channels within a fixed channel set to reduce the chance of cochannel assignment in a reuse cell pattern. The FBCA algorithms based on assigning a channel dynamically but obeying the rule of reuse distance. The distance between the two cells is reuse distance, which is the minimum distance at which no cochannel interference would occur. Very infrequently, no channel can be borrowed in the neighbouring cells. Even those channels currently in operation can be forcibly borrowed and will be replaced by a new channel in the neighbouring cell or the neighbouring cell of the neighbouring cell. If all the channels in the neighbouring cells cannot be borrowed because of interference problems, the FBCA stops.