A dynamic channel assignment scheme for voice/data integration in GPRS networks

In GPRS multiple channels can be allocated to a user and hence GPRS provides users data connection with variable data rates and high bandwidth efficiency. In this paper, we propose a dynamic channel assignment scheme for voice and data integration in GPRS networks. Channel re-allocation scheme (RAS) and de-allocation scheme (DAS), as well as a buffer strategy for voice calls, are adopted to efficiently utilize the available bandwidth. Different from previous work, that usually assumes that one or two channels are required for a GPRS data packet, we generalize the GPRS data channel requirement as M channels (M≥2). Furthermore, we adopt a multi-dimensional Markov model to analyze the performance in terms of the voice call blocking probability, the GPRS packet blocking probability, the average GPRS packet transmission time and the channel utilization. Then we perform an extensive numerical study on the proposed scheme based upon a fixed-point algorithm, and investigate the tradeoff under different system configurations and mobility patterns. Numerical results show that RAS not only significantly decreases the voice call blocking probability and the average GPRS packet transmission time, but also slightly increases the channel utilization, with a negligible degradation on the GPRS packet blocking probability. The conventional assumption for small M (e.g. M=2) underestimates the improvements obtained by RAS. The buffer mechanism helps to further improve the performance, and an optimum buffer length is able to provide a good balance among different performance metrics.