Performance analysis of LAA / Wi-Fi coexistence: Stochastic geometry model

To fulfill the exponential growth of traffic data demand, 3GPP extends the deployment of LTE/LTE-A (Long Term Evolution-Advanced) over the unlicensed band called LAA (Licensed Assisted Access) in released 13. The unlicensed band is a shared spectrum between different radio access terminals (e.g., Wi-Fi, Radar system) and the critical challenge is to maintain a fair coexistence with these technologies when LTE/LTE-A is deployed over the same spectrum. In this paper, we propose a new framework to model and evaluate the performance of LAA/Wi-Fi coexistence based on stochastic geometry to provide a more explicit form of the metric evaluation in LAA/Wi-Fi coexistence scenarios. The analytical and numerical results show that for a given transmission distance and network activity exists an optimal energy detection threshold that would maintain high transmission capacity and fair coexistence in LAA/Wi-Fi random deployment. A variable energy detection threshold based on the transmitter density as provided in this paper would improve both the channel access opportunity and the coverage probability compared to the constant energy detection threshold used in 802.11 and LAA.