Queuing-Based Dynamic Multi-Guard Channel Scheme for Voice/Data Integrated Cellular Wireless Networks

ABSTRACT: In voice/data integrated cellular wireless networks where handoffs occur more often than earlier mobile networks, it’s important to introduce a scheme that gives priority to handoff calls over new calls. From the user’s perspective dropping a handoff call is less desirable than blocking a new one. Furthermore, from the service provider’s point of view the objective is to improve the utilization of the wireless channel. Motivated with these arguments, a new scheme named as (QDCRS) is proposed which combines the features of Dynamic Channel Reservation Scheme (DCRS) and Handoff Queuing Scheme (HQS). The design goal is to maintain a low dropping probability while decreasing the blocking probability and improving the system performance. Traffic is divided into four classes and priority is given in the following order: (1. handoff voice calls, 2. handoff data calls, 3. new voice calls, 4. new data calls). The boundary between traffic classes is dynamically adjusted according to the mobility of calls and status of the network. Moreover, there is a queue (Q) with capacity (K) for handoff data calls. There is no similar queue for other classes of traffic. The proposed scheme is modeled by a two-dimensional Markov chain in order to obtain the steady state probabilities of the system. Performance of the proposed scheme is investigated in terms of blocking/dropping probabilities and channel utilization. Results obtained analytically and through simulation indicate that the proposed scheme exhibits the best Grade of Service (GoS) cost function and performance/cost (Z) function values, compared to the well-known Fully Shared Scheme (FSS) and the Guard Channel Scheme (GCS) and it maintains its superiority under heavy load and variant mobility. Keywords: Voice/data integrated cellular networks, Dynamic channel reservation, Handoff queuing, Quality of Service (QoS). ……………………………………………………………………………………………………………………………………………………………………………………………………………………