This book constitutes the refereed proceedings of the 4th International Workshop on Multiple Access Communications, MACOM 2011, held in Trento, Italy, in September 2011. The 21 full papers presented were carefully reviewed and selected from more than 40 submissions. They are divided in topical sections on cognitive radio; MAC protocols; communications theory; special session on MAC protocols for WSNs; system analysis and scheduling; and, queuing systems.

This book constitutes the refereed proceedings of the 5th International Workshop on Multiple Access Communications, MACOM 2012, held in Maynooth, Ireland, in November 2012. The 13 full papers and 5 demo and poster papers presented were carefully reviewed and selected from various submissions. The papers are organized in topical sections on network coding, handling interference and localization techniques at PHY/MAC layers, wireless access networks, and medium access control.