Multi-channel management for D2D communications in IEEE 802.22 WRANs

IEEE 802.22 standard is the first worldwide standard using cognitive radio (CR) technology for wireless regional area networks (WRANs). Orthogonal frequency-division multiple access (OFDMA) is employed for point-to-multi-point (P2M) communication between base stations (BS) and customer premises equipments (CPEs) in WRANs. The large coverage of a single cell (up to 100 km of radius) is the unique feature of WRANs. However, channel reuse is not considered, i.e., in one slot the channel can be allocated to only one CPE, and every intra-cell packet needs to be routed through the BS. Therefore, device-to-device WRAN (D2DWRAN) has been proposed to support direct intra-cell CPE-CPE communication. Power control strategies are used to achieve higher reuse of OFDMA slots. In this paper, we take one step further to enhance the network capacity by adopting multichannel management (MCM) with infrastructure support. This enables multiple operating channels to be used simultaneously in D2DWRANs. New channel switching strategies are also studied. We implement a MCM scheme in an OFDMA setting for D2DWRANs, and examine it in the upstream (US). For downstream (DS), there are already many proposals in the literature, which can be adopted directly by D2DWRAN. The simulation results show that MCM scheme significantly improves the network performance compared to single-channel D2DWRANs and WRANs.