Analytical Modeling of a Dynamic Handoff Scheme in Mobile Wireless Networks

In wireless networks, terminating handoff calls is generally more objectionable than blocking new calls. The Guard Channel Scheme (GCS) and Handoff Queueing Scheme (HQS) are the popular and practical strategies to prioritize handoff calls. A key issue when giving handoff calls the higher priority is how to achieve a tradeoff among the handoff call blocking probability, new call blocking probability and handoff delay. This paper proposes a new handoff scheme based on GCS and HQS that dynamically manages the channels reserved for handoff calls depending on the current status of the handoff queue. A threedimensional analytic model is developed to analyze this scheme in order to achieve the desirable performance tradeoff. The Poisson process and Markov-Modulated-Poisson-Process (MMPP) are employed to model the new and handoff call arrivals in order to capture their arrival properties, respectively. The accuracy of this model is evaluated through the extensive comparison of the analytical results to those obtained from discrete-event simulation experiments. Performance measures in terms of the mean number of calls in the system, aggregate response time, aggregate call blocking probability, handoff call blocking probability, new call blocking probability and handoff delay are evaluated. The analytical model is used to investigate the impacts of the threshold for managing the handoff call queue on the performance of this new handoff scheme.