Optimal Power Allocation for Relay Assisted Cognitive Radio Networks.
ABSTRACT In this paper, we study the optimal power allocation of wireless relay nodes which are used in the secondary user (SU) communication of a cognitive radio (CR) network. We consider the behavior of transmitting powers of SUs where those powers are limited to the tolerable interference as seen by the primary user (PU) communication. To improve the performance of the secondary communication based on minimizing the outage probability, we re-formulate the power allocation problem with a new set of constraints. These are obtained by considering the co-channel interference generated by the SU communication to the PU communication. The power allocation problem is solved for both regenerative and non regenerative relay models under Rayleigh fading conditions. SU communication with N number of relays is discussed and compared. The outage probability of SU communication is limited by the interference power threshold (IPT) constraints of PUs and is affected significantly by the IPT levels of PUs.
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ABSTRACT: In this paper, we present two optimal resource allocation schemes that maximize throughput and symbol correct rate (SCR). The throughput and SCR are derived. The derived throughput and SCR are optimized with respect to the sensing time, the source transmission power and the relay transmission power. Numerical results show that the optimal sensing time is dependent on the primary user's signal-to-noise-ratio (SNR). They also show that SCR increases with increase in the number of relays.01/2012;
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ABSTRACT: This paper considers optimal resource allocation in integrated framework of cognitive radio and ad hoc network. The design problem looks for an optimal solution in power and channel allocation in multihop cognitive radio network (CRN) with linear topology. The overall goal is to minimize outage probability and enhancement in network lifetime, while meeting the limits of total transmit power and interference threshold to primary user (PU) simultaneously. The problem has been solved using standard technique of solving convex optimization problem and weighted bipartite matching. Simulation results show that the proposed scheme not only minimizes outage probability better compared to existing (only) power allocation strategies but also reduces interference to PU and saves sum transmission power of secondary users (SUs). Furthermore, in view of the energy constraints of the nodes in cognitive radio ad hoc networks, the solution is extended to address the issue of the network lifetime improvement. Simulation results confirm that our extended solution offers better network lifetime, although it shows slightly inferior performance in terms of minimizing outage probability compared to our initial solution.Communication Systems and Networks (COMSNETS), 2013 Fifth International Conference on; 01/2013
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ABSTRACT: This paper proposes an optimal strategy for power allocation algorithm for source and relay nodes in multihop cognitive radio network that minimizes the outage probability of data transmission while meeting the constraints of interference to primary user and total transmit power of cognitive radio users. Overall objective is to enhance the network lifetime along with an increase in sum (total) transmission capacity. Extensive simulations are done for both energy aware (EA) and non-energy aware (NEA) power allocation schemes. Simulation results show that EA based power allocation not only enhances network lifetime but also reduces interference to primary user at the cost of slight decrease in sum transmission capacity compared to NEA based scheme.Wireless Communication Systems (ISWCS), 2012 International Symposium on; 01/2012