Dynamic specrum leasing for beamforming cogniive radio neworks using nework coding

In this paper, we propose dynamic spectrum leasing (DSL) for cognitive radio (CR) networks as an efficient alternative to two way direct communication for legacy/primary networks. We show that using physical layer network coding (PNC) and distributed beamforming, the CR nodes can relay the primary network data for some duration while the spectrum is leased to them. We demonstrate that in DSL operational mode, up to 20 times more data can be successfully exchanged between two primary sources as compared to direct two way communication. Also in DSL, as a reimbursement, the otherwise silent CR nodes that help in relaying can get a fraction of time during which they can carry out their own communication thereby increasing the spectral utilization.