Computationally Efficient Dynamic Code Assignment Schemes With Call Admission Control (DCA-CAC) for OVSF-CDMA Systems

This paper investigates computationally efficient suboptimal dynamic code assignment (DCA) schemes with call admission control (CAC) for orthogonal variable spreading factor code-division multiple-access systems. We examine two different approaches. The first approach reduces the complexity of the DCA scheme by partitioning the total resource (either capacity or service class) into several mutually exclusive subsets and assigns each subset of resource to a group of users in proportion to the corresponding traffic load. The second approach reduces the complexity of the optimal CAC scheme with the Markov decision process over an infinite time horizon by a suboptimal CAC policy, which is designed by observing the behavior of system dynamics over only two consecutive stages upon the arrival of a call. It is demonstrated by numerical evaluation that the proposed schemes achieve an average data throughput close to that of the optimal DCA-CAC performance while demanding a much lower computational complexity in their design and implementation.