On dynamic channel assignment in cellular mobile radio systems

There are two types of strategies to assign the channels to a cell: fixed channel assignment (FCA) and dynamic channel assignment (DCA). The basic characteristics of DCA are presented in comparison with FCA. The authors introduce various DCA strategies and discuss some of most important DCA research topics currently being pursued. In particular, the authors focus on microcellular systems, including a proposed MD (moving direction) strategy. It uses the information a mobile station´s (MS´s) moving direction with the DCA strategy. A channel is selected among those occupied by MSs moving in the same direction with the concerned MS. In this manner, the MS can still use the same channel at the handover with high probability. DCA requires more radio equipment at each base station than FCA, and it requires elaborate channel assignment control. However, it exploits the limited frequency spectrum efficiently and has a lower forced call-termination rate than FCA when the blocking rates are equal