Research on Outage Performance Optimization of Cognitive Relay Network with Cooperative Sensing

In this work, cooperative spectrum sensing technology is applied to optimize the outage probability of cognitive relay networks. The outage performance optimization problem of cognitive relay networks is resolved by designing the sensing time and fusion rule threshold appropriately. The outage probability by high signal to noise ratio (SNR) approximation under Rayleigh fading channels is derived theoretically, and the solution of optimal fusion rule threshold is given. Theoretical analysis and simulation results illustrate that the optimal sensing time and fusion rule threshold exist to minimize the outage probability. The outage performance of cognitive relay networks is significantly improved under the assistance of cooperative sensing compared with that of non-cooperative sensing scheme

ARQ Protocols in Cognitive Decode-and-Forward Relay Networks: Opportunities Gain

In this paper, two novel automatic-repeat-request (ARQ) based protocols were proposed, which exploit coop- eration opportunity inherent in secondary retransmission to create access opportunities. If the signal was not decoded correctly in destination, another user can be acted as a relay to reduce retransmission rounds by relaying the signal. For comparison, we also propose a Direct ARQ Protocol. Specif- ically, we derive the exact closed-form outage probability of three protocols, which provides an effective means to evalu- ate the effects of several parameters. Moreover, we propose a new metric to evaluate the performance improvement for cognitive networks. Finally, Monte Carlo simulations were presented to validate the theory analysis, and a comparison is made among the three protocols

Cognitive Multihop Wireless Sensor Networks over Nakagami-m Fading Channels

This work is supported by the National Science Foundation of China (NSFC) under Grant 61372114, by the National 973 Program of China under Grant 2012CB316005, by the Joint Funds of NSFC-Guangdong under Grant U1035001, and by Beijing Higher Education Young Elite Teacher Project (no. YETP0434)