Enhanced listen-before-talk scheme for LTE in unlicensed band

Extending LTE technology to unlicensed band 5GHz is a research focus to alleviate the problem of scarce spectrum resource. Listen-before-talk (LBT) scheme is necessary in unlicensed band to ensure the fair utilization of spectrum resource among different radio access technologies (RATs). Aiming at overcoming the drawbacks that there are limited opportunities and fixed location for clear channel assessment (CCA) to sense channel in LBT scheme, we propose an enhanced LBT scheme with performing random back-off process and adjusting the times of sensing channel according to the state of channel for LTE with Licensed-Assisted Access (LTE-LAA) to achieve the fairness of channel access. Moreover, we also propose a model in which applies enhanced LBT scheme to calculate the throughput for APs and LTE small cells in the coexistence of WIFI and LTE. Simulation results show that enhanced LBT scheme can solve the problem that the throughput of WIFI is constrained by LTE which uses original LBT scheme in the WIFI-LTE coexistence scenario. Moreover, compared to original LBT scheme, our enhanced LBT scheme can also solve the problem that only one operator can transmit in the coexistence of LTE and LTE deployed by different operators.