Pre-emptive channel allocation model for heterogeneous cellular networks

The authors present a pre-emptive channel allocation model for heterogeneous cellular networks. A heterogeneous cellular network is defined to operate in various communication protocols, and each protocol may suit for certain service classes with different traffic characteristics. For example, GSM is widely used for conveying real-time, high-quality voice traffic and is operating in circuit-switching mode. On the other hand, GPRS and IMT-2000, operating in packing-switching mode, are suitable for conveying burst video or non-real-time bulk data. One of the innovatory designs presented is correct in that a real-time handoff call, operating in circuit-switching mode, is allowed to pre-empt on-going and non-real-time calls, operating in packet-switching mode. For the purpose of evaluation, a mathematical model with 3-D Markov chains is built to analyse blocking probabilities of handoff and new calls with different traffic characteristics under pre-emption. The analyses have shown that with pre-emption the blocking probability of real-time handoff calls can be reduced significantly, as compared to that without pre-emption. Besides, the average number of active calls, the average call completion rate, and the channel utilisation are substantially improved through the pre-emptive channel allocation model.