Throughput analysis of cooperative multi-hop underlay CRNs with incremental relaying

To increase the communication range of multi-hop cognitive radio networks (CRNs) while avoiding the implied loss in throughput, use of incremental relaying has been suggested. In this paper, we discuss an incremental relaying (IR) protocol for cooperative multi-hop CRNs (CMHCRNs). A CMHCRN with multiple decode-and-forward relays in each hop is considered. In each hop, the relays whose received signal-to-noise-ratio (SNR) values are greater than a predefined threshold constitute a qualified relay set (QRS). The performance of an IR protocol that selects a relay from the QRS that has the highest SNR to the destination at each hop of the CMHCRN is analyzed. Both peak transmit power and peak interference power constraints are taken into account. The end-to-end outage probability and throughput expressions are derived for the considered network over Rayleigh fading channels. Closed-form expressions for floor values of outage probability and throughput are also derived. Based on the derived expressions, we demonstrate that with increase in number of hops, throughput first increases and then decreases.