Joint Detection and User Selection Algorithms inCognitive Wireless Communication System

Abstract

Cognitive wireless networks usually utilize large numbers of cognitive nodes to collect cognitive information of the authorized frequency bands and do automatic configuration to finish spectrum sharing processes. How to realize joint detection and choose appropriate cognitive nodes to achieve opportunity type spectrum access should be considered in a cognitive wireless communication system. In this paper, we present a joint detection algorithm to finish cognitive information collection and one user selection scheme to minimize co-channel interference for the downlink of a cognitive mesh network with the coexistence of many primary nodes and cognitive nodes. In the joint detection strategy, the central node controls more than one cognitive user to jointly detect the primary channel. While the effective user selection algorithm is proposed to choose a group of cognitive nodes while maximizing the sum rate of primary nodes and satisfying the co-channel interference constraint from the cognitive nodes to primary nodes, meanwhile, the total transmitted power constraint for primary access point (PAP) as well as the Signal to Interference and Noise Ratio of the cognitive nodes is bigger than a given threshold γ . Simulation results show that our suboptimal algorithm is able to achieve high sum rate throughput with low complexity.