# Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks

## TL;DR

This paper analyzes the performance of dual-hop cognitive radio networks with cooperative diversity under Nakagami-m fading, deriving new analytical bounds and expressions for outage capacity and error probability in different relay scenarios.

## Contribution

It provides novel closed-form bounds and expressions for outage capacity and error probability in two-way cognitive radio networks with cooperative relays under Nakagami-m fading.

## Key findings

- Derived tight lower bounds on outage capacity and ASEP.
- Obtained closed-form expressions for end-to-end outage capacity.
- Validated analytical results with Monte Carlo simulations.

## Abstract

In this paper, we investigate the performance of a dual-hop block fading cognitive radio network with underlay spectrum sharing over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-$m$ fading channels. The primary network consists of a source and a destination. Depending on whether the secondary network which consists of two source nodes have a single relay for cooperation or multiple relays thereby employs opportunistic relay selection for cooperation and whether the two source nodes suffer from the primary users' (PU) interference, two cases are considered in this paper, which are referred to as Scenario (a) and Scenario (b), respectively. For the considered underlay spectrum sharing, the transmit power constraint of the proposed system is adjusted by interference limit on the primary network and the interference imposed by primary user (PU). The developed new analysis obtains new analytical results for the outage capacity (OC) and average symbol error probability (ASEP). In particular, for Scenario (a), tight lower bounds on the OC and ASEP of the secondary network are derived in closed-form. In addition, a closed from expression for the end-to-end OC of Scenario (a) is achieved. With regards to Scenario (b), a tight lower bound on the OC of the secondary network is derived in closed-form. All analytical results are corroborated using Monte Carlo simulation method.