Dynamic code assignment in hybrid MC-CDMA/TDMA systems

1 This study was conducted when the authors were with Graduate Institute of Communication Engineering, National Taiwan University, Taipei, Taiwan 10617. Presentation of this paper is made possible by a grant from the National Science Council, Taiwan (NSC-90-2213-E-260-011). ABSTRACT In the past decade, the market of wireless mobile communications has been growing at a rapid pace. A future wireless mobile network is desired to support integrated type of services including voice, data, video, and etc. A well-designed multiple access control (MAC) protocol is crucial in supplying satisfactory level of performance such as delay or throughput. A dynamic code assignment in hybrid Multi-Code CDMA/TDMA is proposed in this paper. The code assignment scheme is designed to follow the time-varying traffic characteristics of the mobile users. The base station (BS) assigns more codes to the mobiles during congestion but releases them when congestion subsides. Congestion is estimated from the queue lengths of the mobiles. A queueing model is established for performance analysis, in which the traffic source is taken to be a Markov-Modulated Poisson Process (MMPP). The analysis is started from a single connection and extended to multiple connections.