On the Stability of Contention Resolution Diversity Slotted ALOHA (CRDSA)

Abstract

In this paper a Time Division Multiple Access (TDMA) based Random Access (RA)\nchannel with Successive Interference Cancellation (SIC) is considered for a\nfinite user population and reliable retransmission mechanism on the basis of\nContention Resolution Diversity Slotted ALOHA (CRDSA). A general mathematical\nmodel based on Markov Chains is derived which makes it possible to predict the\nstability regions of SIC-RA channels, the expected delays in equilibrium and\nthe selection of parameters for a stable channel configuration. Furthermore the\nmodel enables the estimation of the average time before reaching instability.\nThe presented model is verified against simulations and numerical results are\nprovided for comparison of the stability of CRDSA versus the stability of\ntraditional Slotted ALOHA (SA). The presented results show that CRDSA has not\nonly a high gain over SA in terms of throughput but also in its stability.\n