Accommodating LAA Within IEEE 802.11ax WiFi Networks for Enhanced Coexistence

Given the abundance of unlicensed spectrum in 5 GHz band, licensed-assisted-access (LAA) technology presents an efficient and simple approach to alleviate the spectrum crunch in wireless networks. The recent proposal of IEEE 802.11ax as an advanced WiFi standard to accommodate more high rate connections motivates the investigation with respect to the feasibility and benefits of LAA in coexistence with unlicensed user access under this new WiFi protocol. In this article, we first introduce an enhanced LAA and WiFi coexistence mechanism based on spatial multi-stream transmission within IEEE 802.11ax access. We then derive a stream selection and user replacement strategy based on the proposed synchronous coexistence scheme to improve LAA performance without sacrificing WiFi throughput. We further present a Lyapunov algorithm to optimize the LAA access intensity level with rapid convergence and low-complexity. Numerical results demonstrate the effectiveness of the proposed algorithms, and the mutual benefits of the proposed coexistence framework to both LAA and WiFi users.