CS+: A novel self-adaptive slot assignment scheme for ATDMA

This paper presents the novel slot assignment scheme CS+. CS+ is a full adaptive strategy based on adaptive learning of slot allocation patterns by means of a modified channel segregation approach. It was developed for future cellular systems working with PRMA++, the potential medium access control mechanism of third generation TDMA proposals like the RACE ATDMA system. The paper focuses on the performance of decentralized adaptive slot assignment strategies in microcellular environments. A major problem in such systems is that frequency preplanning, as it is common in macrocellular systems, is very difficult or can not be afforded at all in a microcell environment. Furthermore the interference situation can change very much in an unpredictable way. A slot assignment scheme has to cope with this situation to exploit the subscriber capacity improvements inherent in microcell systems. System evaluation by means of computer simulation shows that only full adaptive slot assignment strategies are really useful in the investigated scenarios. The best results both in interference reduction and I-slot access performance of PRMA++ was obtained by the self-adaptive CS+