Abstract
We propose a two-level call admission control (CAC) scheme for direct sequence code division multiple access (DS-CDMA) wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls) in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls) based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.
Highlights
Recent years have witnessed a great amount of activity on developing the next-generation wireless networks that are expected to provide a wide range of services, such as voice, data, video, and web traffic at very high data rates
Values of system parameters which are specific to the proposed two-level call admission control (CAC) scheme are selected as follows: noise rise coefficient η = 0.1, standard deviation of log-normal shadowing σ = 8 dB, maximum queue size Qpq = 20 class 1 calls, and the average patience time for calls stored in the queue is 100 seconds
We propose a two-level call admission control scheme for wireless direct sequence code division multiple access (DS-CDMA) networks carrying multimedia traffic
Summary
Recent years have witnessed a great amount of activity on developing the next-generation wireless networks that are expected to provide a wide range of services, such as voice, data, video, and web traffic at very high data rates. The two-level CAC scheme proposed in this paper is similar to the single-level CAC scheme presented in [10] by using the SIR as the metric for call admission, assigns priority to real-time calls over nonreal-time calls, and accounts for traffic and resource asymmetry in the uplink and downlink. The two-level CAC scheme proposed in this paper accounts for the provisioned physical resources (e.g., channel elements at the base station) in DS-CDMA wireless networks and incorporates queuing of nonreal-time calls (to take advantage of their delay-tolerant characteristic) during physical resource shortage.
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