Understanding the impact of RADAR interference on IEEE 802.11 MAC in spectrum sharing environments

Electromagnetic spectrum congestion is a serious problem. The majority of the desirable spectrum lie below 6 GHz, and is consumed by communication and RADAR systems. DARPA's Shared Spectrum Access for Radar and Communications (SSPARC) program seeks to improve efficient use of spectrum by allowing RADAR and communication systems to share spectrum in the 3.5 GHz S-band. In this paper, we present some results on the MAC layer performance of the IEEE 802.11 protocol in the presence of RADAR interference. We propose a simple model for the carrier sense multiple access mechanism and use it to gain insight into some important performance metrics such as MAC layer throughput, and packet service time. Finally, we provide some numerical examples to demonstrate the usefulness of the results in designing spectrum sharing strategies in real systems.