Receiver-Aided Spectrum Sensing Scheme with Spatial Differentiation in OFDM Based Cognitive Radio Networks

In this paper, a novel spectrum sensing scheme, called receiver-aided spectrum sensing scheme with spatial differentiation (RaSSSD), is proposed for orthogonal frequency division multiplexing (OFDM) based cognitive radio networks. In RaSSSD, the deployed area of secondary users (SUs) is divided into two sub-areas. By determining which sub-area secondary user transmitter (SUT) and secondary user receiver (SUR) are located through measuring the received signal-to-noise radio (SNR) of primary signal, RaSSSD applies different strategies for channel sensing with the aid of SUR if feasible. Such aid from SUR is implemented through feeding back a state indicator, whose short length would not introduce high overhead and interference. In addition, the theory of partially observable Markov process (POMDP) is used to determine the optimal sub-channel for sensing and access. Numerical results demonstrate that with the proposed RaSSSD, the throughput of SUs can be significantly improved under the limitation of interference to the primary users.