Probability Of Spectrum Handoff Research Articles

Analysis of spectrum handoff schemes for cognitive radio networks considering secondary user mobility

Cognitive radio has been proposed as an intelligent wireless communication system towards the usage of dynamic spectrum access in next generation networks, where the primary users (PU) and secondary users (SU) can share the spectrum, while causing minimum interference to each other. Spectrum mobility is the main element for the effective execution of cognitive radio networks. Spectrum mobility can be achieved by means of spectrum handoff (SHO). Initially, SUs continuously sense the channels to identify an idle channel. Error in sensing channel is possible. A detection theory is put forth to analyse the spectrum-sensing errors with the receiver operating characteristic (ROC) considering false alarm probability, missed detection and detection probability. Also, we meticulously investigate and analyse the probability of spectrum handoff (PSHO) with lognormal-3 and Hyper-Erlang distribution models considering SU call duration and residual time of spectrum holes availability designed for tele-traffic analysis.

Impact of residual time distributions of spectrum holes on spectrum handoff performance with finite switching delay in cognitive radio networks

Cognitive radio technology ascends as a mean to improve the overall spectrum efficiency by exploring the spectrum opportunity and sharing the available channels with secondary users or cognitive users without causing harmful interference to either of the networks. Spectrum handoff is appeared to be a key strategy in order to ensure the required QoS of the primary user network and increase the overall performance of Cognitive Radio Network (CRN). In this paper, we investigate the effect of finite handoff or switching delay on the performance of spectrum mobility in a cognitive radio network. We establish an analytical model for the probability of spectrum handoff and develop an analytical formula of average spectrum handoff of a cognitive user for general residual time distributions of spectrum holes considering finite switching delay. The impact of switching delay and residual time distributions of spectrum holes on performance measuring metrics are investigated. This paper also presents a detailed comparison of results between the proposed time relationship model of spectrum handoff with and without finite switching delay in cognitive radio networks. A close proximity of the simulation result with the analytical one validates the accuracy of the proposed model.

Impact of secondary user mobility on spectrum handoff under generalized residual time distributions in cognitive radio networks

Cognitive Radio is an emerging technology to accommodate the growing demand for wireless technology via dynamic spectrum access to enhance spectrum efficiency. Spectrum handoff is an important component of Cognitive Radio technology for practical implementation of radio frequency access strategy and better utilization of spectrum in both primary and secondary networks. The probability of spectrum handoff and expected number of spectrum handoffs are key parameters in performance analysis and design of the cognitive radio network. This work presents an analytical model to evaluate the impact of secondary users’ mobility on intra-cell spectrum handoff considering primary users’ activity model in a cognitive radio network. A standard form of intra-cell spectrum handoff probability and expected number of intra-cell spectrum handoffs are derived for complete call duration of a non-stationary secondary user. The probability and expected number of intra-cell spectrum handoffs of a post inter-cell handoff call are also derived for generalized residual time distributions of call holding time and spectrum holes. A detailed analysis of these performance measuring metrics is presented under the impact of departure rate and cell crossing rate of secondary users. The accuracy of the derived analytical result is validated by Monte-Carlo simulation of the model.

Performance analysis of cognitive radio networks with generalized call holding time distribution of secondary user

In cognitive radio networks (CRNs), spectrum handoff probability and expected number of spectrum handoffs are important parameters in the evaluation of network performance and design. This paper presents an analytical model for spectrum handoff probability and spectrum handoff rate for CRNs under general distribution of call holding time of secondary users (SUs). The standardized analytical forms of spectrum handoff probability and handoff rate of secondary network under negotiated scenario are derived for a complete service call duration. The effect of mobility parameters: departure rate of SUs ($$\upmu )$$μ) and departure rate of spectrum holes ($$\uplambda )$$ź) on spectrum handoff are also reported in this paper. Extensive results for all the proposed analytical models are obtained and presented in this paper. Analytical results show that exponential and Erlangian distribution functions are not suitable for call holding time of SU in the analysis of spectrum handoff in CRNs. Moreover, the superiority of lognormal distribution function ascertains its use for call holding time of SU in spectrum handoff estimation for better CRN performances. The Monte-Carlo simulation is also performed for spectrum handoff probability to validate the analytical model.

A Comprehensive Analysis of Spectrum Handoff Under Different Distribution Models for Cognitive Radio Networks

The static frequency allocation in wireless communication became a major concern for efficient spectrum utilization. Also due to spatio-temporal variation, some of the frequency channels are not utilized efficiently. The prologue of open spectrum and dynamic spectrum access (DSA) methodology provides the secondary (unlicensed) users, supported by cognitive radios (CRs) to opportunistically utilize the unused spectrum bands. When a primary user returns to the engaged spectrum band, secondary users should release it immediately through proper handing off to another spectrum band available to the network satisfying the quality of service (QoS) of both the network. Hence the focus of the new spectrum management policies is DSA technology based on CR. Spectrum mobility is considered to be the subsequent big challenge in CR technology. Spectrum mobility is associated with spectrum handoff which is directly associated with link maintenance and QoS. In this paper, we scrupulously investigate and analyze the probability of spectrum handoff under diverse realistic primary and secondary user traffic models. We have established a state of the art standard generalized form of probability of spectrum handoff without switching delay considering secondary user call duration and residual time of availability of spectrum holes as measurement metrics for diverse distribution functions designed for tele-traffic analysis. We thoroughly investigate different distribution models for the residual time under both zero switching delay and finite switching delay conditions. The switching delay (tr) between spectrum holes comprises of spectrum sensing time and transition delay for realizing all the related parameters. A comprehensive simulation results are presented to validate the generalized theory established in this paper.

Spectrum handoff in cognitive radio with fuzzy logic control

The secondary usage of spectrum has been investigated in Cognitive Radio (CR) network to resolving the spectrum scarcity issue in wireless communication. When Primary Users (PU) who own the spectrum appear, spectrum handoff is needed to maintain the communications of Secondary Users. But the decision making of spectrum handoff is a challenge issue for CR network, because the input of decision making, which obtain through spectrum sensing, is heterogeneous and inexact. In this paper we will use fuzzy logic control theory to solve this issue and make use of new information for handoff operation: the probability of PU’s occupancy at a certain channel. Our new algorithm can make more intelligent decision compared to simple traditional spectrum handoff decision making and reduce the probability of spectrum handoff, also the performance of SU’s communication can be enhanced.