Stabilized multi-channel ALOHA for wireless OFDM networks

Multiple access based on orthogonal frequency division multiplexing (OFDM), or OFDMA, enables multiple users to simultaneously access the media by using different subcarriers. This leads to the convenient realization of multi-channel ALOHA, in which each user transmits with a group of subcarriers. In this paper, we first introduce the multi-channel slotted ALOHA algorithm to OFDM, which is called OFDMA-based multi-channel ALOHA (OMC-ALOHA). Since ALOHA is an unstable algorithm, we show OMC-ALOHA is also unstable. To solve this stability problem, we extend the pseudo-Bayesian algorithm to achieve stabilized OMC-ALOHA.