Threshold-Based Multichannel Access with Energy Constraint

This paper considers multiaccess control for the uplink in orthogonal-frequency-division-multiple-access (OFDMA) wireless networks. To avoid extensive information exchange with the access point in centralized approaches, we propose a distributed threshold-based scheme, where each user accesses multiple channels simultaneously based on a comparison between measured channel gains and a channel gain threshold. Each user will adapts its channel gain threshold based on local measurements of collision on each channel and the energy consumption for channel contention. The problem is formulated as a constrained non-cooperative game. We show existence and uniqueness of the Nash equilibrium. A gradient-based algorithm is proposed to update the channel gain threshold. Furthermore, the convergence of this algorithm is proved. In addition, for heterogeneous systems, our proposed scheme can maintain multiuser diversity gains considering the time-varying channel gain and energy consumption. Compared with peer distributed OFDMA schemes and random channel selection algorithms, our proposed schemes reduce overhead and achieve a higher throughput.