Throughput maximization for the secondary user over multi-channel cognitive radio networks (original) (raw)

Effective Capacity and Delay Optimization in Cognitive Radio Networks

In this paper, we study the fundamental trade-off between delay-constrained primary and secondary users in cognitive radio networks. In particular, we characterize and optimize the trade-off between the secondary user (SU) effective capacity and the primary user (PU) average packet delay. Towards this objective, we employ Markov chain models to quantify the SU effective capacity and average packet delay in the PU queue. Afterwards, we formulate two constrained optimization problems to maximize the SU effective capacity subject to an average PU delay constraint. In the first problem, we use the spectrum sensing energy detection threshold as the optimization variable. In the second problem, we extend the problem and optimize also over the transmission powers of the SU. Interestingly, these complex non-linear problems are proven to be quasi-convex and, hence, can be solved efficiently using standard optimization tools. The numerical results reveal interesting insights about the optimal performance compared to the unconstrained PU delay baseline system.

Analysis of Secondary Users with an Opportunistic perspective in Cognitive Radio Networks

2017

This paper analyses opportunistic access of secondary user in cognitive radio network (CRN) using analytical M/D/1 queuing model. Through using spectrum sharing, secondary user opportunistically share primary user spectrum when it empty. Through spectrum sharing primary user generates revenue and secondary user maximizes its satisfaction with spectrum utilization. Number of secondary users and their packet waiting time in the system is calculated. Numerical illustration for the same is presented using utility function upper bound and lower bound of primary arrival was determined. By using upper bound and lower bound the optimal secondary 446 K. Gangadhara Rao, Edwin Marco Kwesigabo, B. Basaveswar Rao & K. Chandan arrival is calculated. Results indicate that optimal secondary arrival increases and decreases depending on reward and state of primary user’s arrivals.

Opportunistic Spectrum Access in Cognitive Radio Networks: A Queueing Analytic Model and Admission Controller Design

2007

Cognitive radio (CR) technology is an innovative radio design philosophy in order to increase the spectrum utilization by exploiting the unused spectrum in dynamically changing environments. Specifically, the CR technology will allow a group of potential users (referred to as secondary users) to access available spectrum resources unused by primary users (PUs) for whom the band has been licensed. The spectrum available for secondary users (SUs) depends on PUs' activity in the licensed spectrum. In this paper, we develop a queuing analytic framework to study important performance measures experienced by SUs in a CR network. We study queuing delay and buffer statistics of SUs' packets by modeling PUs' activity as a two state Markov chain and SUs' channel quality variation as a finite state Markov chain (FSMC). In order to allocate available channels among the SUs, an opportunistic channel allocation scheme is considered. The proposed framework facilitates to design an admission controller for SUs' network in order to maintain a given quality service (QoS) requirement which is specified in the form of statistical delay guarantee.