Spectrum Sharing of Radar and Wi-Fi Networks: The Sensing/Throughput Tradeoff

The approach to spectrum sharing explored in this paper is based on unilateral action by Wi-Fi networks to prevent unacceptable interference to incumbent search radars (e.g., those operating in S-band). Specifically, we evaluate the ability of a single Wi-Fi network to speedily detect radar operation and to subsequently switch to a clear channel as a means of protecting them. We rely on the opportunistic use of naturally occurring random quiet/idle periods in a Wi-Fi network employing distributed coordination function to detect the presence of a radar using energy detection. We analytically characterize the statistical properties of the idle periods in terms of occurrence and duration in the full buffer and downlink only traffic cases, and verify our analysis using simulations. We then suggest simple modifications to Wi-Fi parameters in order to improve radar detection performance and examine the resulting Wi-Fi throughput costs. The key contribution of this paper is to thoroughly characterize the Wi-Fi throughput versus detection tradeoff implicated by this coexistence mechanism.