Call Admission Control Jointly with Resource Reservation in Cellular Wireless Networks

Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010, Article ID 740575, 10 pages doi:10.1155/2010/740575 Research Article Call Admission Control Jointly with Resource Reservation in Cellular Wireless Networks Aytül Bozkurt,1 Rafet Akdeniz,2 and Erdem Uçar3 1 Department of Electronics Technology, Namık Kemal University, 59860 Tekirdağ, Turkey 2 Department of Electronics and Telecommunication Engineering, Namık Kemal University, 59860 Tekirdağ, Turkey 3 Department of Computer Engineering, Trakya University, 22100 Edirne, Turkey Correspondence should be addressed to Aytül Bozkurt, Received 9 November 2010; Accepted 25 December 2010 Academic Editor: Nicholas Kolokotronis Copyright © 2010 Aytül Bozkurt et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. To efficiently utilize the total resources and to serve mobile users demanding for different types of service, system resource utilization of these services should be considered, and efficient resource management techniques should be developed. In this paper, we propose a new call admission control (CAC) scheme jointly with resource management by considering the two service types: prioritized calls and nonprioritized calls. Proposed scheme limits the new and handoff prioritized and non-prioritized call arrivals according to call-level quality of service (QoS) requirements. By searching algorithm, admission parameters are obtained optimally and required QoS are guaranteed. Due to high priority of the prioritized calls, the admittance of non-prioritized calls into channel is restricted, while prioritized calls are admitted as long as there is sufficient bandwidth. To evaluate the performance of the proposed CAC scheme, we have compared the numerical results from the analytical model with those of New Call Bounding scheme. It is shown that the proposed CAC scheme uses the resources effectively and improves all the upper-bound QoS requirements with respect to the New Call Bounding scheme for prioritized and non-prioritized users. 1. Introduction In cellular wireless networks, to integrate multiservice with desired QoS, efficient resource management techniques are needed, while specified level of QoS is guaranteed to users belonging to each service class [1]. In a wireless network, maximum packet delay for nondelay tolerant services, error-free transmission for delay-tolerant services must be guaranteed and maximum delay response must be provided for seamless image effect. Mobility, frequent handoffs and limited bandwidth are important constraints for QoS in wireless networks. Service quality can be studied in three different levels as follows. (1) Packet level: in packet level, specified QoS parameters such as dropping probability, maximum packet delay and jitter must be guaranteed to users. (2) Call level: in call level, users expect that both blocking probability of new calls and dropping probability of handoff calls should be at minimum value. Handoff calls dropping is less desired than new calls blocking. For this reason, it is needed to decrease the probability of handoff calls at the expense of increasing the probability of new calls. (3) Class level: class level QoS is related to how bandwidth is shared by various classes of users. Common bandwidth sharing techniques are complete sharing (CS) complete partitioning (CP) and restricted access (RA) [2]. Any class of users can use the entire bandwidth as long as sufficient capacity exists in CS. Bandwidth is partitioned at the beginning as a default value among incoming class of users in CP. Call Admission Control schemes are the most efficient techniques used in the resource management. CAC coupled with resource management provides both maximum utilization in given bandwidth and call-level QoS requirements [3]. When the total bandwidth is shared, higher priority is given to handoff calls to decrease the dropping probability. In the literature, CAC has been studied widely and several CAC schemes were proposed [4–12]. Priority-based CAC schemes have also been proposed to provide the handoff calls with lower dropping probability over the new calls [4–6]. Three call admission schemes known widely have 2 EURASIP Journal on Wireless Communications and Networking been studied for different channel holding times of the new and handoff calls for only one service in [4] and a new approximation approach was proposed to reduce the computational complexity. In [5], exact product-form solution is studied to evaluate the symmetric CAC schemes such as New Call Bounding scheme in multiservice networks where different channel holding times of all the classes of calls are different. In [6], for multiple priorities, elasticthreshold-based CAC was designed and its performance was evaluated in terms of maximum reward obtainable with QoS satisfaction and threshold values were determined by sequentially adjusting the thresholds based on reward and reject rate. CAC scheme proposed in [7] supports multiple admission priority classes. Proposed scheme adopts dynamic guard loading concept in which it adapts the threshold limits based on the current estimates of multiple handoff classes requests derived from current number of ongoing calls in neighboring radio cells and the mobility pattern. Another priority-based scheme is proposed and analyzed for integrated voice and data based on resource preemption [8]. Proposed scheme deploys RA bandwidth sharing technique in which highpriority prioritized calls can all bandwidth unrestrictive way when there is enough capacity. If there is unoccupied bandwidth by prioritized calls upon the arrival of a new or handoff data calls, arriving data calls use the remaining bandwidth from the prioritized calls. This leads to available bandwidth usage of the data calls and better system resource utilization and performance results. In [9, 10], optimal CAC is proposed by adopting the semi-Markov Decision Process (SMDP) to model the call admission scheme and bandwidth reallocation algorithm at the same time for time-varying multimedia traffic. A dynamic priority CAC is proposed in [11] to achieve better balance between CS and CP by computing the dynamic priority level based on predefined load partitions and the current carried load. In [12], two types of traffic are considered and partitioned to four priority classes; bandwidth reservation is made according to priority class. Although proposed scheme reserves different amounts of bandwidth for each prioritized class, bandwidth reservation thresholds are not optimal values. In this paper, we propose a new call admission control scheme with adjusted capacity allocation to utilize the network resources efficiently. The main novelty in the proposed scheme is that maximum K (kbps) amount of adaptable bandwidth is allocated to nonpriori (...truncated)