Multiple access communications in future-generation wireless networks (editorial)

The ALOHA System Research project began in September 1968, with the purpose of defining those situations where radio communications are preferable to conventional wire communications. The 802.11 WiFi wireless standard modified the CD part of the Ethernet standard to Collision Avoidance (CA) to define the CSMA/CA protocols adopted in 1997 for WiFi. Ironically, recent chatter on the web dealing with full duplex WiFi hints at further development of WiFi in the direction of the original ALOHA architecture. The complexity of the proposed algorithm increases only linearly with the number of users. In this algorithm, the different CFOs from different users destroy the orthogonality among training sequences and introduce multiple access interference (MAI). To reduce the effect of the MAI, the authors find the CAZAC sequence that maximizes the signal-to-interference ratio.