"COOPERATIVE SPECTRUM SENSING IN COGNITIVE RADIOS : PERFORMANCE EVALUATION FOR HETEROGENEOUS COOPERATING NODES"

Abstract

The rapid growth in wireless communications has contributed to a huge demand on the deployment of new wireless services .Cognitive Radio (CR) is the promising solution of underutilized licensed spectrum. Thus the two most popular research areas when it comes to CR are spectrum sensing and interference management and resource allocation. Spectrum sensing is the ability to find available frequencies/timeslots to transmit in. The detection of PUs in practical wireless channels with a single CR sensor is challenging due to several issues such as the hidden node problem, path loss, shadowing, multipath fading, and receiver noise/interference uncertainty. In this context, Cooperative Spectrum Sensing (CSS) is considered a promising technique in order to enhance the overall sensing efficiency. Existing CSS methods mostly focus on homogeneous cooperating nodes considering identical node capabilities, equal number of antennas, equal sampling rate and identical Signal to Noise Ratio (SNR). However, in practice, nodes with different capabilities can be deployed at different stages and are very much likely to be heterogeneous in terms of the aforementioned features. In this context, CSS technique for the heterogeneous nodes with different capabilities on the basis of different sensing techniques i.e. energy detection based spectrum sensing technique and eigen value based spectrum sensing technique was analysed. The performance of this CSS technique was evaluated by the use of Receiver Operating Characteristics (ROC) and complementary Receiver Operating Characteristics (ROC) curves over additive white Gaussian noise (AWGN) channel.