Coded Random Access

Abstract

This chapter presents an overview of coded slotted ALOHA (CSA), which is a slotted ALOHA-based random access scheme with iterative interference cancellation. The iterative reception algorithm of CSA is analogous to the iterative belief-propagation erasure-decoding, motivating the use of the tools from codes-on-graphs to design and analyze CSA schemes. The asymptotic performance analysis of CSA for the collision channel model is derived using the and-or tree evaluation and instantiated for the case of frameless ALOHA. The and-or tree evaluation is then adapted to the case of block-fading channels and threshold-based reception criterion, which is another frequently used model in wireless systems. Finally, the performance of CSA is assessed in multi access point scenario for the collision channel model, assuming different variants of cooperation among the access points.