Enabling co-channel coexistence of 802.22 and 802.11af systems in TV White Spaces

In this paper, we investigate the coexistence problem between the 802.22 and the 802.11af systems in the TV White Spaces (TVWS). We focus on the design of a co-channel coexistence scheme for the 802.22 customer-premises equipments (CPE) and the 802.11af systems. 802.22 and 802.11af are two typical standards envisioned to be widely adopted in the future. However, these two standards are heterogeneous in both power level and PHY/MAC design, making their coexistence challenging. To avoid mutual interference between the two systems, existing solutions have to allocate different channels for the two networks. Due to the city-wide coverage of the 802.22 base station (BS), the spectrum utilization is compromised with existing schemes. In this paper, we first identify the challenges to enable the co-channel coexistence of the 802.22 and the 802.11af systems and then propose a busy-tone based framework. We design a busy-tone for the 802.22 CPEs to exclude the hidden 802.11af terminals. We also show that it is possible for the 802.11af systems to identify the exposed 802.22 CPE transmitters and conduct successful transmissions under interference. We show through extensive simulations that the spectrum utilization can be increased with the proposed co-channel coexistence scheme.