Teletraffic issues related to channel allocation in digital mobile cellular networks

In this paper, the performance of channel allocation schemes for TDMA type Digital Mobile Cellular systems are studied. We study by simulation the effect of traffic loading and characteristics, including new call arrivals and inter-cell handovers, on blocking and drop out probabilities. The channel allocation schemes under examination includes: (1) Fixed Channel Allocation (FCA) where the number of frequency carriers in each cell is fixed, (2) Dynamic Channel Allocation where the number of frequency carriers in each cell is adaptive and dependent on the load, and (3) Dynamic Frequency/Time Channel Allocation where the number of channels is adaptive (based on the load), allowing two different time division channels of the same frequency carrier to be used in two neighbouring cells. We also study the possible benefit of a simple channel reservation scheme on these systems. We demonstrate that the effects of arrival rate on blocking and drop out probabilities are as expected. As the arrival rate increases, the blocking as well as the drop out probabilities increases. We demonstrate that the implementation of channel reservation is suitable for FCA but not suitable with schemes that is capable of dynamic channel allocation as it may actually worsen drop out rates in such schemes. We also demonstrate that under overload situation, there is no significant benefit in the dynamic schemes and in certain situation they may even performance worse than FCA.