Cell Cooperation Based Channel Access Mechanism for LAA and WiFi Coexistence

In 2014, the 3rd Generation Partnership Project (3GPP) proposed the ‘‘Licensed-Assisted Access using LTE’’ (LAA) research project, with the intention to further improve LTE network capacity by deploying LTE system in 5GHz unlicensed frequency band. But deploying LAA in unlicensed band will inevitably affect other existing wireless systems such as WiFi and increase the risk of data collision. Therefore, the research of coexistence between LAA and WiFi is of great significance to facilitate the fair sharing and efficient utilization of unlicensed spectrum sources. However, the existing studies consider the relationship between LAA and WiFi in the coexistence scenario from the perspective of contention. In this paper, we proposed a cell cooperation based channel access mechanism. The basic idea of the proposed scheme is let an LAA cell and a WiFi cell establish a pair of cooperative relationship. Once LAA node accesses the channel, it will notify its cooperated pair WiFi node to share the transmission opportunity, and vice versa. After the transmission of the LAA node, the WiFi node can access the channel without performing backoff again. Simulation results manifest that the proposed cell cooperation based channel access mechanism improves the communication performances of both LAA and WiFi as well as the spectrum efficiency in the coexistence scenarios with high channel resources demand.