Performance estimation of call admission control schemes based voice/data integrated wireless cellular network with customer retrials

The impact of customer retrial phenomenon due to impatient users in call admission control (existing and proposed) based voice/data integrated system has been modelled, analyzed, and explored. The main aim of this research work is to find the actual situation of system performance in the presence of retrial phenomena and to show unambiguously that the retrial phenomena due to impatient users do degrade the performance, i.e., QoS (quality-of-service) of the system and this paper quantitatively measures and shows/presents this degradation mainly using plots/graphs. Previously the retrial phenomenon was investigated by other researchers using very simplified models with almost no call admission control schemes (CACS). The novelty of this paper is that it has done the work by integrating almost all the major and effective tools and techniques together with two state-of-the-art or cutting edge CACSs, namely - DTBR (Dual Threshold Bandwidth Reservation) scheme, and DP (Dynamic Partition) scheme that can deal with multidimensional traffic in voice/data integrated cellular networks. Retrial phenomenon is incorporated in DTBR and DTBRRCD (DTBR with Reserved Channel for Data) schemes. DTBRRCD is a DP-like DTBR scheme which is proposed to extend or modify DTBR to give data priority. CACS are used to ensure maximum user support with minimum bandwidth, i.e., much improved channel efficiency and at the same time to give QoS (quality-of-service) assurance for each type of traffic. This paper integrated queuing model and approximate continuous time Markov chain (CTMC). Approximate CTMC was used to prevent "state-space explosion" in the case of large user populations.