Enhanced LBT algorithm for LTE-LAA in unlicensed band

In this paper, we focus on the deployment of LTE technologies coexisting with Wi-Fi technologies in the unlicensed spectrum 5 GHz. Listen before talk (LBT) functionality is required in unlicensed band in order to ensure the fair coexistence among different operators. We propose a LBT enhancement algorithm with contention window size adaptation for LTE with Licensed-Assisted Access (LTE-LAA) in order to achieve not only channel access fairness but also the QoS fairness. Simulation results show that LTE-LAA with LBT mechanism does not impact Wi-Fi services more than an additional Wi-Fi network. Compared with the fixed LBT mechanism, our proposed LBT algorithm could achieve around 4% and 6% LTE-LAA performance gain in user perceived throughput (UPT) and transmission latency, respectively. And, more than 25% Wi-Fi transmission latency gain can be also achieved. Furthermore, the simulation result shows the advantage of proposed LBT algorithm over original LBT procedure in the case of two LTE operators coexistence.