Primary User Traffic Pattern Based Opportunistic Spectrum Handoff in Cognitive Radio Networks (original) (raw)

Traffic Pattern Based Adaptive Spectrum Handoff Strategy for Cognitive Radio Networks

Increase in number of commodity devices using network connection raised the spectrum demand largely. The present static spectrum allocation policy gave birth to the so called spectrum scarcity problem. Cognitive Radio enhances the bandwidth usage through Dynamic Spectrum Access without affecting the allocated spectrum, therefore offers a feasible solution to the problem of spectrum scarcity. Enhancing the spectrum usage efficiently, cognitive radio technology allows secondary users to acquire underutilized licensed spectrum band. Smooth spectrum mobility in cognitive radio networks is extremely necessary to ensure the continuity and quality of service. This work aims to develop a dynamic horizontal handoff strategy that adopts according to the traffic pattern of PU. Proposed model keeps track of mobility patterns on certain primary spectrum and classifies these spectrum channels based on primary user's arrival on them. Handoff strategy decision is based on these classified patterns, which can be either proactive or reactive strategy. Analytical results demonstrate that proposed model optimizes channel utilization, minimize handoff delays while maximizing overall network capacity. Keywords—cognitive radio network (CRN); dynaic spectrum access (DSA); handoff stretegies;

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.

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.

An effective spectrum handoff scheme for Cognitive Radio Ad hoc Networks

2017

Cognitive Radio Networks (CRNs) is the key technology to overcome the disadvantages of static spectrum allocation and enhance spectrum utilization through Dynamic Spectrum Access (DSA) techniques. One important topic of the development of CRNs is spectrum handoff, which ensures the uninterrupted communication of Secondary Users (SUs). Two types of spectrum handoff approaches exist, namely the proactive and the reactive spectrum handoff. When the Primary User (PU) traffic is high the proactive spectrum handoff approach is more suitable whereas the reactive handoff on light PU traffic achieves better performance. In this paper we evaluate the use of proactive and reactive spectrum handoff policies in CRNs. Simulations are conducted using NS-3 simulator. To the extent of our knowledge, an extensive CRN simulation regarding spectrum handoff on NS-3 simulator has not been carried out. Furthermore, we implemented a hybrid spectrum handoff scheme that selectively uses either reactive or pr...

Challenges of Spectrum Handoff in Cognitive Radio Networks

akamaiuniversity.us

Cognitive Radio (CR) with Dynamic Spectrum Access (DSA) could alleviate the shortage of radio resources. Secondary Users (SUs) (unlicensed users) could access the spectrum when Primary Users (PUs) (licensed users) are inactive. The service interruption loss arises as secondary users try to handoff the channel to the legitimate users of the channels, the primary user. This new type of loss is different from losses as a result of network congestion and channel errors, experienced also by conventional wireless networks. Transport layer protocols' performance of an SU could be degraded significantly as it tries to handoff channel due to the arrival of a PU. The need to investigate SU's TCP performance during this period of sensing, hand-off, and looking for an alternative channel to continue transmitting is a challenging one. This paper presents a study of the challenges of spectrum handoff as PUs in CR networks appear in the course of an ongoing transmission by the SUs. A TCP rate adapting algorithm that ensures seamless spectrum handoff as PUs appear is proposed.

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...

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 ...

Efficient Spectrum Handoff Using Hybrid Priority Queuing Model in Cognitive Radio Networks

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.

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...