Abstract:
Cognitive Radio is a promising technology that enables simultaneous sharing of spectrum via multiple users (i.e., primary and secondary users) through opportunistic access mechanism. This technology heavily relies on specific spectrum sensing algorithm which enables it to uniquely identify spectrum holes (i.e., vacant portions of spectrum) and thus allocating better spectrum portion to secondary users. Initially, the researchers developed spectrum sensing techniques for single spectrum band. However, recently multiband spectrum sensing schemes got significant popularity. In this thesis, we focused on multi-band spectrum sensing schemes in centralized cognitive radio network to cater interference that occurs due to the sudden appearance of primary users and increases overall system throughput as compared single spectrum sensing scheme. We have utilized diversity combining scheme to improve the detection capability of our proposed algorithm. Furthermore, we used a double threshold energy detection algorithm which reduced the probability of collision between primary and secondary users. Independent and randomly placed relays are used as observing units to analyze system‟s performance, whereas simulations are carried out using energy detection in rician fading environment. At the end we show all the important results of our proposed multi-band spectrum sensing which improves the system‟s performance as compared to single-band spectrum sensing.
