Optimum Utilization of Spectrum Holes in Cognitive Radio Networks using Opportunistic Spectrum Band Allocation Policy for Handoff Prioritization (original) (raw)
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Spectrum Handoff Strategies in Cognitive Radio Networks
2014
Today, Cognitive Radio (CR) have a promising solution to both spectrum inefficiency and spectrum scarcity issues by enabling secondary users (SUs) to exploit the idle frequency bands temporarily in opportunistic manner as long as the primary users (PUs) do not occupy their spectrum. The SUs must vacate these frequency bands when the PUs come back and reuse them. This is one of challenge in CR technology. In this case, the communication links of the SUs must be finding another idle frequency bands to resume their communication links. This is called spectrum handoff which is affecting to the performance of system by main factors such as: link maintenance probability, the number of spectrum handoff, switching delay. Spectrum handoff may be happen more than once for a wide range of the spectrum available in CR. This switching change the characteristics of propagation transmission loss which is affects the overall system performance. Thus, in this thesis, the path loss and coverage area ...
Novel Hybrid Spectrum Handoff for Cognitive Radio Networks
International Journal of Wireless and Microwave Technologies, 2013
Cognitive radio (CR) is pro jected as a technology (or solution) that will raise the spectrum utilizat ion considerably by allowing low-priority or secondary user (SU) to utilize the spectrum of high-priority or primary user (PU) opportunistically. Spectru m handoff is a different type of handoff necessitated by the reappearance of the primary user on the frequency channels occupied by the secondary user at that time and location. In this paper, a hybrid type of spectrum handoff algorith m is proposed where proactive decision and reactive decision approaches are combined. Depending on the arrival rate o f primary user (i.e. PU activ ity), the algorith m switches fro m reactive decision mode to proactive decision mode and vice versa. The switching fro m one mode to another mode depends on threshold value of PU activity and we evaluated the threshold value through analysis for switching of the algorithm to be 0.37. Simu lated results show that the proposed hybrid spectrum handoff algorith m reduces the total service t ime of secondary user considerably compared to conventional proactive decision or reactive decision handoff approaches.
A Study on Quantitative Parameters of Spectrum Handoff in Cognitive Radio Networks
The innovation of wireless technologies requires dynamic allocation of spectrum band in an efficient manner. This has been achieved by Cognitive Radio (CR) networks which allow unlicensed users to make use of free licensed spectrum, when the licensed users are kept away from that spectrum. The cognitive radio makes decision, switching from primary user to secondary user and vice-versa, based on its built-in interference engine. It allows secondary users to makes use of a channel based on its availability i.e. on the absence of the primary user and they should vacate the channel once the primary user re-enters and continue their communication on another available channel and this process in the cognitive radio is known as spectrum mobility. The main objective of spectrum mobility is that, there is no interruption caused due to the channel occupied by secondary users and maintains a good quality of service. In order to achieve better spectrum mobility, it is mandatory to choose an eff...
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Wireless Personal Communications, 2019
Cognitive radio networks can achieve high spectrum efficiency through dynamic spectrum allocation to the secondary users (SU) by way of using primary user (PU) spectrum. An efficient handoff scheme for cognitive radio networks using hybrid priority queuing model has been proposed using discretion rule. This method is divided into two parts: (1) hybrid priority queuing model with discretion rule is proposed by prioritizing the secondary users in the channel and then calculate the waiting time during the spectrum handoff and (2) to obtain better efficiency by reducing the waiting time, the learning rate of the secondary users from the other users should be increased. This can be done with multi teacher apprentice learning (MAL) along with sparse regression by considering multiple users into consideration at a time instead of a single user for better efficiency of the spectrum. The normalized load, arrival rate and the service time of the proposed model is compared to the existing models with respect to the average data delivery time of the users.
Spectrum Handoff in Cognitive Radio Networks: A Survey
Oriental journal of computer science and technology, 2017
Cognitive radio (CR) is a promising solution to improve the spectrum utilization by enabling unlicensed users to exploit the spectrum in an opportunistic manner. Spectrum handoff is a different type of handoff in CR necessitated by the reappearance of primary user (PU) in the licensed band presently occupied by the secondary users (SUs). Spectrum handoff procedures aim to help the SUs to vacate the occupied licensed spectrum and find suitable target channel to resume the unfinished transmission. The purpose of spectrum mobility management in cognitive radio networks is to make sure that the transitions are made smoothly and rapidly such that the applications running on a cognitive user perceive minimum performance degradation during a spectrum handoff. In this paper, we will survey the literature on spectrum handoff in cognitive radio networks.
A Spectrum Selection Framework for Mobility Handoff in Cognitive Radio Cellular Network
2012
Cognitive radio (CR) offer solution by utilizing the spectrum holes in space without introducing an unacceptable fear of harmful interference for the primary user. And also solve the spectrum inefficiency and spectrum scarcity problem. That are represented the potential opportunities for non-interfering use of spectrum which requires three main tasks Spectrum Sensing, Spectrum Analysis and Spectrum Allocation. In this paper, A spectrum selection framework for mobility handoff in cognitive radio cellular network, First introduced the Spectrum decision making is to determine a set of spectrum bands by considering the application requirement as well as the dynamic nature of spectrum band and user handoff process each spectrum is characterized by jointly considering primary user activity and spectrum sensing operations. Based on this, dynamic resource management scheme is developed to coordinate the spectrum decision adaptively dependent on the time-varying cognitive radio network capac...
“Study of Spectrum Allocation Techniques for Primary and Secondary User in Cognitive Radio Networks”
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Cognitive network in an effective technique for utilization of spectrum. In wireless communication one of the most recent advancement is leading to flexibility of spectrum usage. According to licensed spectrum policy, a large part of spectrum remains useless and it is leading to wastage of spectrum. In recent wireless communication, a major demand for this technology is for fair spectrum assignment to unlicensed (secondary) users. This led to the technological development of cognitive radio. Which optimize the spectrum usage. For effective usage of radio frequency spectrum, cognitive radio networks have been proposed and allowing the secondary user to occupy the spectrum whenever the primary user is not using it. To avoid interference with the primary user, secondary user should constantly check the usage of spectrum.Current networking scenario is facing the great scarcity of spectrum and cognitive networks is promising to solve the problem of spectrum.
MODELLING OF COGNITIVE RADIO SYSTEM FOR THE IMPROVEMENT OF SPECTRUM UTILIZATION
Cognitive radio is a capable technology, which has provided a different way to increase the efficiency of the electromagnetic spectrum utilization. CR allows unlicensed users or secondary users (SUs) to use the licensed spectrum through dynamic channel assignment strategies or spectrum access when the primary users (PUs) are in a dormant state to improve the spectrum utilization and hence avoid spectrum scarcity. For this we need intelligent spectrum sensing techniques which can detect the presence of spectrum holes and allocate them to the secondary users without interfering with the activities of the primary users.The model of interaction among users in CR networks consisting of a single PU and SU. This scheme is less computationally complex while at the same time being fair. It was found that at its best from a throughput optimization and less delivery loss perspective. This ability to provide fair throughput allocation among secondary users was found to improve.
Primary User Traffic Pattern Based Opportunistic Spectrum Handoff in Cognitive Radio Networks
Applied Sciences
Through the expeditious expansion of the wireless network, the unlicensed bandwidth-based devices are growing substantially as compared to the present vacant bandwidth. Cognitive radio networks present a proficient solution to the spectrum shortage diminution hitch by allowing the usage of the vacant part of the spectrum that is not currently in use of the Primary User licensed bandwidth to the secondary user or cognitive radio user. Spectrum management procedure in cognitive radio network comprises of spectrum sharing, sensing and handoff. Spectrum handoff plays a vital role in spectrum management and primarily focuses on single handoff strategies. This paper presents a primary user traffic pattern-based opportunistic spectrum handoff (PUTPOSH) approach to use in the cognitive radio networks. PUTPOSH permits a secondary user to sense the arrival of a primary user and use an opportunistic handoff scheme. The opportunistic handoff scheme firstly detects the arrival of the primary use...
J. Inf. Sci. Eng., 2018
Spectrum handoff probability, spectrum handoff rate or average number of spectrum handoffs are important parameters in the evaluation of performance metrics of Cognitive Radio Networks. Due to the mobility of spectrum holes, a Cognitive Radio user needs to perform spectrum handoff successfully to complete its data transmission. This paper scrupulously investigates and analyzes the probability of spectrum handoff under diverse realistic primary and cognitive user traffic models. A theoretical analysis of spectrum handoff probability and average number of spectrum handoffs is presented here under the assumption that the residual time of spectrum holes are exponential, Erlangian and Weibull distributed. We also present impact of departure rate of cognitive users (μ) and spectrum holes (λ) on the probability of spectrum handoff and rate of spectrum handoffs. The accuracy of the derived distribution is validated by simulation results for the Weibull (k=3) distribution function and a deta...