A Cournot Game Approach in the Duty Cycle in CSAT Algorithm for WiFi/LTE-U Coexistence

With the rapid development of the information age, the licensed frequency bands used by mobile cellular communications have become more crowded, while unlicensed frequency bands still have more spectrum resources available. Therefore, mobile cellular communication operators hope to provide better services to users by shifting some services to unlicensed bands. The current mechanisms to realize the coexistence of WiFi and LTE mainly include License Assisted Access(LAA) technology based on listening before talk(LBT) and LTE-U system by using Carrier-Sensing Adaptive Transmission(CSAT) algorithm. In general, the CSAT algorithm adjusts the duty cycle by increasing or decreasing a fixed length of time of each cycle, which results in some cases that only one cycle cannot accurately set the duty cycle accurately, requiring multiple long enough periods to adjust the duty cycle, thus making the duty cycle setting more reasonable. In this paper, the duty cycle configuration of CSAT, is optimized by Cournot game model. At the same time, using this model, a dynamic algorithm for solving duty cycle based on Cournot game is proposed, which provides an idea for CSAT technology to configure duty cycle. Compared with the original CSAT technology to adjust the duty cycle, the algorithm can shorten the adjustment period, reduce the time delay of 1-4 transmission cycles, and can better adapt to the dynamic network scenarios.