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Performance Analysis <strong>of</strong> Spillover-Partitioning Call Admission Control<strong>Author</strong> Pro<strong>of</strong>162163164165166167168169170171<strong>Here</strong>, we note that <strong>the</strong> class priority <strong>of</strong> a service class is inherently associated with <strong>the</strong>service class and is not related to traffic demand. A high-priority class call has a high rewardrate associated to it and typically requires more channels for service (such as a multimediacall). It could be that a low-priority class has a high traffic demand and thus <strong>the</strong> system willreserve more channels to <strong>the</strong> class to satisfy <strong>the</strong> QoS requirement and to maximize <strong>the</strong> rewardrate obtainable. However, <strong>the</strong> priority or importance <strong>of</strong> a class remains <strong>the</strong> same and will notbe changed with increasing traffic demands.The total revenue R T generated by each cell per unit time is <strong>the</strong> sum <strong>of</strong> <strong>the</strong> revenuegenerated from each service class:R T = R 1 h + R1 n + R2 h + R2 n (1)<strong>Here</strong>, R i 172 hrepresents revenue earned from servicing class i hand<strong>of</strong>f calls per unit time, andR i 173 n represents revenue earned from servicing class i new calls per unit time.The QoS constraints <strong>are</strong> expressed in terms <strong>of</strong> blocking probability thresholds, Bt 1 174 h , Bt1 n ,Bt 2 175 h ,andBt2 n , for class 1 hand<strong>of</strong>f, class 1 new, class 2 hand<strong>of</strong>f, and class 2 new calls, respec-176 tively. Suppose that <strong>the</strong> hand<strong>of</strong>f dropping probability and new call blocking probability <strong>of</strong>class i generated by a CAC algorithm <strong>are</strong> B i 177 h and Bi n . Then <strong>the</strong> imposed QoS constraints <strong>are</strong>178 satisfied when:179 B 1 h < Bt1 h ; B1 n < Bt1 n ; B2 h < Bt2 h ; B2 n < Bt2 n . (2)180 The optimization problem that, we <strong>are</strong> solving is to maximize R T in Eq. 1 subject to <strong>the</strong>181 constraints specified in Eq. 2.1823 Spillover-Partitioning Call Admission Control185183 For ease <strong>of</strong> disposition, we assume that two service classes exist with class 1 being <strong>the</strong> high-184 priority class. The algorithm <strong>can</strong> be easily extended to <strong>the</strong> case in which more classes exist.Let c_min i n/hdenote <strong>the</strong> minimum number <strong>of</strong> channels needed to satisfy <strong>the</strong> new/hand<strong>of</strong>f186 QoS constraints for class i alone. We first sort all service calls by c_min i n/hto determine <strong>the</strong>service order. For example if <strong>the</strong> order is c_min 1 h ≥ c_min1 n ≥ c_min2 h ≥ c_min2 n , <strong>the</strong>n our188 service order would be class 1 hand<strong>of</strong>f calls, class 1 new calls, class 2 hand<strong>of</strong>f calls, and189 class 2 new calls. We <strong>the</strong>n divide channels into partitions to serve calls in this service order.190 The number <strong>of</strong> partitions doubles <strong>the</strong> number <strong>of</strong> service classes in order to service both new191 and hand<strong>of</strong>f calls. When two classes exist, <strong>the</strong>re <strong>are</strong> four partitions P 1 , P 2 , P 3 ,andP 4 .The192 first partition is reserved for class 1 hand<strong>of</strong>f calls only; <strong>the</strong> second partition is reserved for193 class 1 calls including both hand<strong>of</strong>f and new calls; <strong>the</strong> third partition is reserved for class 1194 calls and class 2 hand<strong>of</strong>f calls; and <strong>the</strong> last partition is open to all call types.195 The algorithm is “spillover” in <strong>the</strong> sense that if a service call <strong>can</strong>not be admitted into P i196 <strong>the</strong>n it will overflow to P i+1 and so on, as long as P i is a partition that <strong>can</strong> accept it.197 Figure 1 illustrates <strong>the</strong>se four partitions allocated by <strong>the</strong> spillover-partitioning CAC algo-198 rithm. When a call is received, <strong>the</strong> partition with <strong>the</strong> lowest index which <strong>can</strong> accept this call199 is used. If this partition does not have enough channels to accommodate <strong>the</strong> call, <strong>the</strong>n <strong>the</strong>200 next partition is used. As an example, when a high priority (class 1) hand<strong>of</strong>f call is received,201 P 1 is used unless this partition is full. If this partition is full <strong>the</strong>n P 2 is used and so on. Similar202 rules will apply for o<strong>the</strong>r service calls. For example, if a high priority new call comes, P 2203 would be used unless this partition is full. Spillover-partitioning, by <strong>the</strong> virtue <strong>of</strong> allocating204 several partitions to high-priority classes, <strong>can</strong> satisfy stringent constraints <strong>of</strong> high-priorityuncorrected pro<strong>of</strong>123Journal: 11277 MS: WIRE823 CMS: 11277_2009_9673_Article TYPESET DISK LE CP Disp.:2009/2/19 Pages: 21 Layout: Small

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