Performance of an Improved Energy Detector in Multihop Cognitive Radio Networks.

Cooperative spectrum sensing in a multihop cognitive radio (CR) network based on multiple antennas using an improved energy detector is studied in this paper. The improved energy detector uses the $p$th power of the absolute value of samples of primary user's (PU's) signals. We replace the conventional energy detector by an improved energy detector to enhance the performance of CR. Analytical expressions of the probability of false alarm and missed detection in each CR are derived. Furthermore, we extend our study to a multihop cooperative <bold>diversity</bold> system containing <bold>multiple</bold> multihop secondary transmission paths between the PU and the fusion center. Performance analysis of multihop cooperative diversity is discussed using an improved energy detector. We introduce a framework to derive a closed-form expression of the optimal number of multihop cooperative diversity branches by minimizing the total error rate. An efficient quick spectrum sensing algorithm is proposed, which requires fewer than the total number of cooperative multihop diversity branches. It is shown, through various numerical examples, that by using the optimal number of secondary transmission paths, it is possible to perform quick spectrum sensing while satisfying an upper bound on the total error rate. [ABSTRACT FROM PUBLISHER]