Performance of Multi-Carrier LBT Mechanism for LTE-LAA
Jian-Guo Liu, Gang Shen · 2016
In Rel-13, Licensed-Assisted Access (LAA) to unlicensed spectrum has been approved as a new work item to meet the increasing traffic demands for operators. For LAA, the listen-before-talk (LBT) is an efficient way to ensure fair and friendly coexistence in unlicensed band with other operators and radio access technologies (RATs). To use more bandwidth, multiple unlicensed carriers could be aggregated and activated independently for LAA. However, the general LBT mechanism is unfeasible for multi-carrier operation due to the RF leakage at transmitter side, which would result in the saturation of the channel sensing in neighbouring carrier and thereby a low probability of simultaneous data transmission over multiple carriers. In this paper, we first analyze the coexistence mechanism for Wi-Fi and LAA. After that, we propose an effective LBT mechanism for LAA multi- carrier operation so as to provide better coexistence fairness with other technologies (e.g. Wi-Fi) and to increase bandwidth utilization. Furthermore, the simulation results show that the proposed solution could provide better fairness and performance in comparison with other solutions when LAA coexists with Wi-Fi.