DO-Fast: a round-robin opportunistic scheduling protocol for device-to-device communications

In this paper, we consider the distributed opportunistic scheduling problem for the Orthogonal Frequency Division Multiplexing OFDM-based device-to-device (D2D) communications, where D2D links contend for access to the dedicated spectrum with limited assistance from cellular infrastructures. Particularly, a synchronous distributed opportunistic scheduling protocol under fairness constraints (DO-Fast) is prompted. In DO-Fast, a round-robin strategy is integrated with the opportunistic scheduling to tackle the trade-off between system throughput and access fairness. Moreover, without instantaneous channel state information at receivers, we incorporate a priority allocation scheme, where access priorities are assigned randomly in a local fashion. Consequently, DO-Fast is robust against imperfect channel estimates and inaccurate channel state information ordering. In addition, the opportunistic strategy in DO-Fast is distinguished from the existing ones in that efficient spatial reuse is exploited by allowing concurrent transmissions based on the signal-to-interference ratio scheduling criterion. Meanwhile, access opportunities are moderately granted for poor quality links by the round-robin strategy for fairness considerations. We analyze and compare three practical scheduling strategies in terms of the access probability. We also evaluate access fairness through Jain's Index. It is shown via numerical and simulation results that DO-Fast could achieve efficient spectrum utilization and guarantee the short-term fairness. Copyright (c) 2014 John Wiley & Sons, Ltd.