Call Admission Control in Cellular Networks

The service area of a cellular network is divided into cells. Users are connected to base stations in the cells via radio links. Channel frequencies are reused in cells that are sufficiently separated in distance so that mutual interference is below tolerable levels. When a new call is originated in a cell, one of the channels assigned to the base station of the cell is used for communication between the mobile user and the base station (if any channel is available for the call). If all the channels assigned to this base station are in use, the call attempt is assumed to be blocked and cleared from the system (blocked calls cleared). When a new call gets a channel, it keeps the channel until either the call is completed inside the cell or the mobile station (user) moves out of the cell. When the call is completed, the channel is released and becomes available to serve another call.