22 March 2018

Channel assignment strategies

The channel assignment strategies can be classified as fixed or dynamic depending on the system performance in managing cell calls when a mobile user is handed off from one cell to another.

Fixed channel assignment : 

In the fixed channel assignment method each cell is assigned a predetermined set of voice channel.

Any effort that is done to call a number within the cell can be serviced by the unused channels in that particular cell.

In case if all the channels in that cell are used, then the cell is blocked. such a situation the subscriber does not  get service.

Borrowing techniques are used from an adjacent cell if all of its channels are occupied. This method is called as borrowing strategies.

Dynamic channel assignment :

In dynamic channel assignment strategy there is no permanent allocation of channels. Every time a call request is done, the BS full form (base station) requests a channel from MSC full form is mobile switching center.

Mobile switching center only allocates the channel after verifying that the channel is not currently in use in the cell or any other cell that comes within the minimum restricted distance of cellular frequency reuse to avoid co channel interference.

Dynamic channel assignment strategy reduces the probability of blocking and increases the trunking capacity of the system. These strategies need MSC to collect real time data.