79 research outputs found
Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks
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- 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
Outage performance of underlay cognitive radio networks over mix fading environment
In this paper, the underlay cognitive radio network over mix fading environment is presented and investigated. A cooperative cognitive system with a secondary source node S, a secondary destination node D, secondary relay node Relay, and a primary node P are considered. In this model system, we consider the mix fading environment in two scenarios as Rayleigh/Nakagami-m and Nakagami-m/Rayleigh Fading channels. For system performance analysis, the closed-form expression of the system outage probability (OP) and the integral-formed expression of the ergodic capacity (EC) are derived in connection with the system's primary parameters. Finally, we proposed the Monte Carlo simulation for convincing the correctness of the system performance
Wireless-Powered Communication Assisted by Two-Way Relay with Interference Alignment Underlaying Cognitive Radio Network
This study investigates the outage performance of an under-laying
wireless-powered secondary system that reuses the primary users (PU) spectrum
in a multiple-input multiple-output (MIMO) cognitive radio (CR) network. Each
secondary user (SU) harvests energy and receives information simultaneously by
applying power splitting (PS) protocol. The communication between SUs is aided
by a two-way (TW) decode and forward (DF) relay. We formulate a problem to
design the PS ratios at SUs, the power control factor at the secondary relay,
and beamforming matrices at all nodes to minimize the secondary network's
outage probability. To address this problem, we propose a two-step solution.
The first step establishes closedform expressions for the PS ratios at each SU
and secondary relay's power control factor. Furthermore, in the second step,
interference alignment (IA) is used to design proper precoding and decoding
matrices for managing the interference between secondary and primary networks.
We choose IA matrices based on the minimum mean square error (MMSE) iterative
algorithm. The simulation results demonstrate a significant decrease in the
outage probability for the proposed scheme compared to the benchmark schemes,
with an average reduction of more than two orders of magnitude achieved
Outage analysis of the power splitting based underlay cooperative cognitive radio networks
In the present paper, we investigate the performance of the simultaneous wireless information and power transfer (SWIPT) based cooperative cognitive radio networks (CCRNs). In particular, the outage probability is derived in the closed-form expressions under the opportunistic partial relay selection. Different from the conventional CRNs in which the transmit power of the secondary transmitters count merely on the aggregate interference measured on the primary networks, the transmit power of the SWIPT-enabled transmitters is also constrained by the harvested energy. As a result, the mathematical framework involves more correlated random variables and, thus, is of higher complexity. Monte Carlo simulations are given to corroborate the accuracy of the mathematical analysis and to shed light on the behavior of the OP with respect to several important parameters, e.g., the transmit power and the number of relays. Our findings illustrate that increasing the transmit power and/or the number of relays is beneficial for the outage probability.Web of Science2122art. no. 765
- …