Bit error rate of underlay multi-hop cognitive networks in the presence of multipath fading

The bit error rate (BER) performance of underlay multi-hop cognitive networks with arbitrary number of hops in the presence of multi-path fading is thoroughly analyzed in this paper. A novel exact analytic expression under consideration of both interference power constraint and maximum transmit power constraint is derived in closed-form and is extensively corroborated by Monte-Carlo simulations. This expression facilitates in evaluating effectively the network performance behaviour in key operation parameters as well as in optimizing system parameters. A multitude of analytical results expose that underlay multi-hop cognitive networks experience the performance saturation phenomena while their performance considerably depends on the number of hops for the linear network model.