4 research outputs found
Joint Sensing and Reception Design of SIMO Hybrid Cognitive Radio Systems
In this paper, the problem of joint design of Spectrum Sensing (SS) and
receive beamforming (BF), with reference to a Cognitive Radio (CR) system, is
considered. The aim of the proposed design is the maximization of the
achievable average uplink rate of a Secondary User (SU), subject to an
outage-based Quality-of-Service (QoS) constraint for primary communication. A
hybrid CR system approach is studied, according to which, the system either
operates as an interweave (i.e., opportunistic) or as an underlay (i.e.,
spectrum sharing) CR system, based on SS results. A realistic Channel State
Information (CSI) framework is assumed, according to which, the direct channel
links are known by the multiple antenna receivers (RXs), while, merely
statistical (covariance) information is available for the interference links. A
new, closed form approximation is derived for the outage probability of primary
communication, and the problem of rate-optimal selection of SS parameters and
receive beamformers is addressed for hybrid, interweave and underlay CR
systems. It is proven that our proposed system design outperforms both underlay
and interweave CR systems for a range of system scenarios
Outage Probability Analysis of Dual Hop Relay Networks in Presence of Interference
Cooperative relaying improves the performance of wireless networks by forming a network of multiple independent virtual sources transmitting the same information as the source node. However, interference induced in the network reduces the performance of cooperative communications. In this work the statistical properties, the cumulative distribution function (CDF) and the probability density function (PDF) for a basic dual hop cooperative relay network with an arbitrary number of interferers over Rayleigh fading channels are derived. Two system models are considered: in the first system model, the interferers are only at the relay node; and in the second system model, interferers are both at the relay and the destination. This work is further extended to Nakagami-m faded interfering channels. Simulation results are presented on outage probability performance to verify the theoretical analysis