A simulation study of multiple access and adaptive forward error control in multimedia wireless networks

Different strategies for error control are investigated, in conjunction with a MAC-level protocol, operating in a multimedia noisy cellular environment, where a base station coordinates mobile users within each cell. The channel multiplexing structure is based on Time Division (TDM), and the slots in each frame are dynamically assigned to the users and their service classes. The access rights are decided by an algorithm, namely, the Independent Stations Algorithm (ISA), at the cell base station, which broadcasts this information to the users. Each single mobile station is associated a bit error probability, which changes with time in a random fashion. Bit error probabilities are estimated and the protection level of the FEC code is dynamically adapted to the new conditions. The performance of the scheme is analyzed by simulation in the presence of mixed voice and data traffic, and with different error handling techniques (FEC and ARQ).