Numerical Approach to Performance Analysis of Multi-Parametric CAC in Multi-Service Wireless Networks
Agassi Z. Melikov, Mehriban Fattakhov · InTech eBooks · 2011
Reliability 170from different cells several times during call duration, which means that channel occupation period is not the same as call duration.Mathematical models of call handling processes in multi-service CWN can be developed adequately enough based on theory of networks of queue with different type of calls and random topology.Such models are researched poorly in literature, e.g.see [4]-[6].This is explained by the fact, that despite elegance of those models, in practice they are useful only for small dimensional networks and with some limiting simplifying assumptions that are contrary to fact in real functioning wireless networks.In connection with that, in majority of research works models of an isolated cell are analyzed.In the overwhelming majority of available works one-dimensional (1-D) queuing models of call handling processes in an isolated cell of mono-service CWN are proposed.However these models can not describe studying processes in multi-service CWN since in such networks calls of heterogeneous traffics are quite differ with respect to their bandwidth requirement and arrival rate and channel occupancy time.In connection with that in the given paper two-dimensional (2-D) queuing models of multi-service networks are developed.In order to be specific we consider integrated voice/data CWN.In such networks real time voice calls (v-calls) are more susceptible to possible losses and delays than non-real time data (original or handover) call (d-calls).That is why a number of different CAC strategies for prioritization of v-calls are suggested in various works, mostly implying use of guard channels (or cutoff strategy) for high priority calls [7], [8] and/or threshold strategies [9] which restrict the number of low priority calls in channels.In this paper we introduce a unified approach to approximate performance analysis of two multi-parametric CAC in a single cell of un-buffered integrated voice/data CWN which differs from known works in this area.Our approach is based on the principles of theory of phase merging of stochastic systems [10].The proposed approach allows overcoming an assumption made in almost all of the known papers about equality of handling intensities of heterogeneous calls.Due to this assumption the functioning of the CWN is described with one-dimensional Markov chain (1-D MC) and authors managed simple formulas for calculating the QoS metrics of the system.However as it was mentioned in [11] (pages 267-268) and [12] the assumption of the same mean channel occupancy time even for both original and handover calls of the same class traffic is unrealistic.The presented models are more general in terms of handling intensities and the equality is no longer required.This paper is organized as follows.In Section 2, we provide a simple algorithm to calculate approximate values of desired QoS metrics of the model of integrated voice/data networks under CAC based on guard channels strategy.Similar algorithm is suggested in Section 3 for the same model under CAC based on threshold strategy.In Section 4, we give results of numerical experiments which indicate high accuracy of proposed approximate algorithms as well as comparison of QoS metrics in different CAC strategies.In Section 5 we provide some conclusion remarks. The CAC based on guard channels strategyIt is undisguised that in an integrating voice/data CWN voice calls of any type (original or handover) have high priority over data calls and within of each flow handover calls have high priority over original calls. www.intechopen.com Numerical Approach to Performance Analysis of Multi-Parametric CAC in Multi-Service Wireless Networks How to referenceIn order to correctly reference this scholarly work, feel free to copy and paste the following: Agassi Melikov and Mehriban Fattakhova (2011).Numerical Approach to Performance Analysis of Multi-Parametric CAC in Multi-Service Wireless Networks, Cellular Networks -Positioning, Performance Analysis, Reliability, Dr.