Performance evaluation and comparison of the R-ISA multiaccess protocol for packet radio

The R-ISA (radio-net-independent stations algorithm) access protocol has been developed and used to support effectively the interconnection of several PCs or workstations to a service station on a local area network through a shared radio channel. The basic characteristics are the alternate use of the channel by the central station and the peripheral population, the use of binary channel feedback, and the distributed calculation of the access rights for the peripheral stations on the basis of a vector of individual presence probabilities of packets, under an independence assumption. Explicit use is made of the a priori information on the packet generation rate σ at each peripheral station (in practice, an estimate of this quantity is periodically constructed); disconnected stations are assigned a default value σ_d. Extensive simulation results are provided and used to assess the dependence of performance on σ_d and other parameters and to compare the protocol with other protocols