Opportunistic Resource Scheduling for LTE-Unlicensed With Hybrid Communications Modes

The rapidly increasing amounts of mobile traffic have brought new challenges on the limited spectrum resource. LTE on the unlicensed band, namely, LTE-U, under the carrier aggregation technology has been considered as a potential solution to handle the increasing demand for high data rate that could provide a higher transmission data rate, spectrum efficiency, as well as seamless mobile user experience. To ensure the fairness access between LTE-U BSs in unlicensed bands, in this paper, we consider the multiple LTE-U base stations (BSs) in the same interference region sharing unlicensed bands. We first analyze the hybrid full-duplex/half-duplex transmission mode of LTE-U BSs based on the network status. Although there is throughput gain from the full-duplex transmission, it cannot always provide a superior performance than the half-duplex transmission mode due to the influence of the self-interference. In addition, we further extensively investigate the opportunistic multiple LTE-U BSs access scheme on the unlicensed band based on the channel bidding mechanism to guarantee the opportunistic harmonious sharing on unlicensed bands among LTE-U BSs. Third, a bidding-based dual-band resource allocation scheme is proposed with dynamic hybrid transmission mode to achieve the maximum network utility while guaranteeing the packet delay constraint and minimizing the packet drop rate under the Lyapunov optimization. Finally, various simulation results demonstrate that the algorithm we proposed could achieve a considerable performance improvement with respect to the schemes in the literature.