An adaptive access control mechanism for LAA and Wi-Fi coexistence in unlicensed band

In this paper, an adaptive access control mechanism is proposed for License Assisted Access (LAA) and Wi-Fi coexistence in unlicensed band. In the proposed mechanism, an adaptive adjustment mechanism for Clear Channel Assessment (CCA) is introduced based on the channel usage efficiency for Wi-Fi system and cellular system. When the access priority of Wi-Fi is guaranteed, the backoff window size of both Wi-Fi access points (APs) and cellular base stations (BSs) can be adjusted adaptively according to the quality-of-service (QoS) of different nodes. With the proposed mechanism, the delay and access success rate performance of coexisting system can be improved, while the normalized throughput can be guaranteed in the high density scenarios. Markov models are used for theoretical analysis. System level simulation results validate the advantages of the proposed mechanism compared with the existing mechanisms.