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

The stability of Random Access protocols is of high importance to ensure an efficient usage of resources and good service perception by the users. In this paper the stability region for the recently proposed Contention Resolution Diversity Slotted ALOHA random access protocol is discussed for finite user populations. The system dynamics of a CRDSA Random Access channel are described and a mathematical model is formulated, which allows predicting the stability of the system. From the derived model quantitative approximations of the stability regions and parameter selection for stable operation are provided. Numerical results are derived by means of simulations for validating the mathematical model and the quantitative approximations of the stability region.