Interoperator Opportunistic Spectrum Sharing in LTE-Unlicensed

Abstract

Extending long-term evolution (LTE) to unlicensed bands, termed LTE-unlicensed, is gaining significant interest recently. The coexistence of LTE-unlicensed with the current users of unlicensed bands (such as Wi-Fi) and the interference among LTE-unlicensed users themselves are the two challenges for the success of this new technology. In this paper, we propose a novel distributed online algorithm for opportunistic sharing of unlicensed bands among LTE-unlicensed base stations (BSs) while guaranteeing the quality of service (QoS) of user equipment (UE). We first derive a Lyapunov optimization-based algorithm for BSs to evaluate the true value of unlicensed spectrum, guarantee a maximum delay, and minimize the packet drop rate. We then develop a distributed auction mechanism to maximize the social welfare in each auction and enable optimal spectrum reuse. We prove that BSs bid truthfully with the proposed algorithm, while UEs’ QoS requirements on delay and packet drop rate can be guaranteed with bounded optimality gaps. We also reveal an interesting tradeoff between the delay and packet drop rate. The proposed algorithm is validated with simulations.