A Study on Quantitative Parameters of Spectrum Handoff in Cognitive Radio Networks (original) (raw)
Related papers
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 ...
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...
A B S T R A C T 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.
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.
Performance of Cognitive Radio Spectrum Access with Intra- and Inter-Handoff
Opportunistic spectrum access (OSA) is a technology that allows unlicensed users to access spectrum holes and to provide so efficient use of radio resources. Most studies done on OSA focus on the situation when the unlicensed user performs the spectrum handoff only within a single cognitive radio network (so-called intra-handoff). In this paper, we consider the users (licensed or unlicensed) to be able to do inter-handoff among different cognitive radio cells as well. The cells provide priority to inter-handoff users. By considering multiple cells being in steady-state and showing identical statistics, the arrival rates of inter-handoff users are determined. We study the OSA performance of unlicensed users under both intra- and inter-handoff schemes, with respect to the blocking and forced-termination probabilities of unlicensed users as well as the unlicensed user service-completion and inter-handoff throughputs. Our Markov chain based numerical analysis is validated by simulation ...
Analysis of secondary user performance in cognitive radio networks with reactive spectrum handoff
Telecommunication Systems, 2016
Cognitive radio networks use dynamic spectrum access of secondary users (SUs) to deal with the problem of radio spectrum scarcity. In this paper, we investigate the SU performance in cognitive radio networks with reactive-decision spectrum handoff. During transmission, a SU may get interrupted several times due to the arrival of primary (licensed) users. After each interruption in the reactive spectrum handoff, the SU performs spectrum sensing to determine an idle channel for retransmission. We develop two continuous-time Markov chain models with and without an absorbing state to study the impact of system parameters such as sensing time and sensing room size on several SU performance measures. These measures include the mean delay of a SU, the variance of the SU delay, the SU interruption probability, the average number of interruptions that a SU experiences, the probability of a SU getting discarded from the system after an interruption and the SU blocking probability upon arrival.
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...
Dedicated Radio Utilization for Spectrum Handoff and Efficiency in Cognitive Radio Networks
IEEE Transactions on Wireless Communications, 2015
To perform spectrum handoff, cognitive radio (CR) nodes communicating with each other need to exchange licensed user detection information, i.e., perform spectrum coordination, over a common control channel. The spectrum coordination can be fulfilled either via existing cognitive radio interface with time division or via a separate dedicated radio, i.e., a common control interface (CCI), continuously. CR nodes with CCI can instantly exchange licensed user detection information and cease frame transmission, while spectrum coordination can only be performed after the frame transmission period without CCI. Nevertheless, the impact of CCI incorporation into CR nodes in terms of common performance metrics must be thoroughly assessed to evaluate the worthiness of additional radio cost. In this paper, an analytical framework is presented to assess the impact of CCI incorporation into CR nodes for spectrum handoff. The developed framework enables analyzing potential benefits and disadvantages of employing CCI for spectrum handoff, in terms of achievable delay, energy consumption, spectrum utilization and event estimation performance. Extensive performance evaluations are presented to illustrate the impact of CCI utilization on efficiency of spectrum handoff. The network and communication regimes that would yield having CCI favorable are characterized in terms of spectrum conditions and CR parameters.
International Journal of Trend in Scientific Research and Development, 2018
In modern society wireless communication plays a very important role with huge increase of users, services and standards. Although there are pros of using cognitive radio networks, for example increasing the spectrum utilization of wireless networks, but still there exist some challenges which need to be discussed in detail: First, since cognitive radio networks are planned to operate heterogeneous spectrum environment, which comprises of both licensed and unlicensed spectrum bands, most of the research has been done in only the licensed band of the spectrum and only some research has been carried out in such an environment as merging licensed and unlicensed spectrum bands for transmission increases the spectrum utilization of cognitive radio wireless networks. There is need to develop new spectrum handoff schemes to improve the performance of the secondary users in terms of their handoff delay.