RESOURCE RESERVATION SCHEME WITH RETRIAL FOR IMPROVED GSM NETWORK PERFORMANCE
The need to increase the number of channels in a limited radio spectrum while covering a large area in a mobile cellular network has lead to the use of various cell design techniques. With an increased number of channels, handover calls can be dropped while moving from one cell to another in the search of a better signal or as a result of user mobility. New calls are also blocked when the traffic channels are fully occupied. However, new calls should be treated fairly and not to be entirely blocked from gaining access to the network as a result of the lack of free channels when the handover requests are absolutely comfortable. In this project, the challenges associated with blocked new calls and dropped handover calls, which are the most important determinants of Quality of Service (QoS) in a cellular network have been carefully examined. First, service optimization is achieved by employing a reservation scheme and a retrial queueing scheme. Secondly, an analytical model that employs the phase merging technique has been formulated. A two dimensional continuous time markov chain (CTMC) was also introduced to provide a complete description of the system states and their transitions. The simulation results show that the reservation scheme with retrial has improved the system performance by minimizing to a large extent the blocking probability and the handover dropping probability. These results have also been recommended to the network operator for service optimization of the cellular network even under high load conditions.