Self-coexistence and spectrum sharing in device-to-device WRANs

IEEE 802.22 wireless regional area network (WRAN) standard employing cognitive radios is gaining much attention recently. The WRAN standard targets reuse of unused TV channels. We propose a device-to-device wireless regional area network (D2DWRAN) to extend the capacity of IEEE 802.22. Network capacity can be increased by supporting direct intra-cell device to device (D2D) communication through channel reuse and also with aggregation of nonadjacent multiple operating channels. Self-coexistence of neighboring IEEE 802.22 cells is a major challenge in WRANs, since the availability of channels varies frequently and channels are reused by every cell as much as possible. Currently, IEEE 802.22 does not consider D2D communication. We propose a two-tier spectrum sharing mechanism for channel allocation in D2DWRANs - both at intra-cell and inter-cell levels. Algorithms and a thorough analysis are presented. We examine our proposal through simulations. Results show significant performance improvement compared to IEEE 802.22. However, there are many hurdles to cross, such as, coexistence with other cognitive radio networks (CRNs), the intra-cell routing, allocation of other network resources, etc. We believe that further work in this domain can lead to increase in capacity not only in WRANs but also in other cellular networks.