A fair listen-before-talk mechanism for LTE-U using a coalition formation approach

摘要

LTE on unlicensed bands (LTE-U), which is a promising way to meet the increasing mobile data demand, has attracted world-wide interests. However, the fair coexistence of LTE-U and WLAN is a critical issue to be solved. In this paper, we devise a semi-distributed channel access approach for LTE-U in dense deployed scenario to improve its capacity and achieve fair coexistence with WLAN. Specifically, the basic listen-before-talk (LBT) mechanism is employed to guarantee the fairness for WLAN, which is similar with the medium control access (MAC) protocol of WLAN. However, in order to decrease the high collision probability at heavy traffic load, a coalition strategy is introduced, in which the LTE-U base stations (BSs) would form into groups, and each group would contend for accessing the channel as one entity. This will effectively reduce the number of stations contending for accessing the channel and the collision probability as a result. In particular, in order to obtain the coalition solution, the cooperative game theory is introduced, and a low-complexity coalition formation algorithm is proposed based on the concept of recursive core in cooperative game. Simulation results verify the effectiveness of the proposed channel access approach, especially improving the LTE-U capacity and ensuring the fairness between LTE-U and WLAN.