A hybrid channel allocation algorithm to reduce call blocking probability using hot-spot notification

In wireless mobile communication systems, the radio spectrum is limited resource. However, efficient use of such limited spectrum becomes more important when the two, three or more cells in the network become hot-spot. The use of available channels has been shown to improve the system capacity. The role of channel assignment scheme is to allocate channels to cells in such way as to minimize call-blocking probability or call dropping probability and also maximize the quality of service. In this paper attempts are made to reduce call-blocking probability by designing hybrid channel allocation (HCA) which is the combination of fixed channel allocation (FCA) and dynamic channel allocation (DCA). A cell becomes hot-spot when the bandwidth available in that cell is not enough to sustain the users demand and call will be blocked or dropped. A simulation result shows that HCA scheme significantly reduces call-blocking probability in hotspot scenario and compared with cold-spot cell. This hot-spot notification will request more than one channel be assigned to the requesting cell, proportional to the current hot-spot level of the cell. Furthermore, all channels will be placed in a central pool and on demand will be assigned to the base station. That will be helpful to reduce call-blocking probability when cell becomes hot-spot. When a call using such a borrowed channel terminates, the cell may retain the channel depending upon its current hot-spot level therefore HCA has comparatively much smaller number of reallocations than other schemes. It also shows that it behaves similar to the FCA at high traffic and to the DCA at low traffic loads as it is designed to meet the advantages of both.