A Distributed Opportunistic Access Scheme for OFDMA Systems

Abstract— In this paper, we propose a distributed opportunistic access scheme for uplink OFDMA systems. The sub-carriers are grouped into several sub-channels. Users access these subchannels through a distributed access scheme without requiring extensive information exchange with the access point. Our scheme allows several parallel contention sub-channels to exploit the multiuser diversity. Using knowledge of all the sub-channels obtained through a periodically transmitted beacon signal from the access point, all users contend on their strongest sub-channel(s). The proposed scheme applies a novel backoff mechanism utilizing this sub-channel knowledge to yield further throughput improvement in addition to the throughput gain obtained by the collision reduction design. To a user, the better the sub-channel gain is, the smaller the backoff time on that sub-channel, and hence, the higher the access priority of the user on that sub-channel. Compared with the traditional centralized OFDMA ...

• Type: Conference
• Year: 2006
• Where: GLOBECOM
• Authors: Dandan Wang, Hlaing Minn, Naofal Al-Dhahir
• Keywords: Access Point, Access Scheme, GLOBECOM 2006, Opportunistic Access Scheme, Telecommunications