New call and handoff call management scheme for reuse partitioning based cellular systems

In cellular networks, blocking occurs when a Base Station has no free channel to allocate to a mobile user. There are two kinds of blocking. New call blocking refers to blocking of newly originated calls and the handoff dropping refers to blocking of ongoing calls due to the mobility of the users. From the user's point of view, the service of a handoff request is more important, as the forced termination of an ongoing call is more annoying than the blocking of new calls. In this paper, an adaptive guard channel based call admission control scheme is proposed which also deals with the problem of non-uniform traffic demand in different cells of the cellular network. A common set of channels are determined dynamically which can be used simultaneously in all the cells. Cell tiers with different radii are used to cope with the interference introduced by using same set of channels simultaneously in all cells. The adaptive guard channels alleviate the considerable amount of increase in the new call blocking probability due to guard channels while it can still protect handoff calls. The performance of the proposed scheme is presented in terms of call blocking probability, call dropping probability and channel utilization. Simulation results show that the proposed scheme can reduce the call blocking as well as call dropping significantly in highly congested cell.