IJERT-Spectrum Mobility in Cognitive Radio (original) (raw)
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Spectrum Mobility in Cognitive Radio
International Journal of Engineering Research and, 2020
Cognitive radio networks gives a powerful solution for spectrum shortage problem using powerful spectrum access. So in highly powerful network, the user other than primary communication is mostly break, spectrum mobility is a powerful tool for enabling continuous Secondary User data transfer. Namely, Secondary User performs spectrum handoff by transmission ongoing communication to a void channel. This paper provide some important points of spectrum mobility in Cognitive radio networks. Comparing of various handoff policy is considered concerning handoff latency. And important designs and related research challenges are also discussed.In this we discussed some policy of transmission their advantages and disadvantages. We also discussed current issues in spectrum mobility.And at the application and further use is discusses. We have therefore created a user interface (UI) for the successful transmission of secondary user frequency to black holes or empty holes.
A Survey on Spectrum Mobility in Cognitive Radio Network
International Journal of Computer Applications, 2015
Cognitive radio technology is an emerging technology which would enable a set of secondary users (SU) to opportunistically use the spectrum allocated to a primary user (PU) and has potential to serve as a solution to spectrum inefficiency and spectrum shortage problems. However, SUs face number of challenges based on the fluctuating nature of the available spectrum. When PU arrives on a specific frequency band, any SU occupying this band should free the channel for PUs which is referred as Spectrum Mobility. It is an important but unexplored event in cognitive radio network. This paper is a brief overview on the reason, mechanism, challenges and their solutions in spectrum mobility.
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 Review on Spectrum Mobility for Cognitive Radio Networks
2015
Cognitive radio is one of the technologies which has the potential to improve the spectrum utilization and network performance. Spectrum Mobility is an indispensable component in cognitive radio network that not only guarantees desired QoS of primary users but also grants resilient service for secondary users. Spectrum Mobility occurs when the primary user appears in the licensed band occupied by secondary user and it is used to avoid interference between primary and secondary users. This paper provides a systematic current overview of spectrum mobility process, various performance metrics and challenges regarding spectrum mobility are pointed out and finally a number of promising concepts and schemes are briefly presented.
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...
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 ...
2013
Two main problems in wireless communications are, limited available spectrum and inefficiency in the spectrum allocation policy. These problems lead to the blocking of both initial and hand-off calls. Cognitive radio (CR) offers solution by utilizing the spectrum holes in space without introducing an unacceptable fear of harmful interference for the primary user and also solves the spectrum inefficiency and spectrum scarcity problem. Spectrum allocation scheme is proposed in two phases. In the first phase, a collision between two calls for spectral band allocation is resolved. In second phase, spectral band allocation among a number of calls is considered. The main objective is to minimize the forced termination of hand-off calls and to achieve opportunistic spectrum channel allocation by assigning different priority levels to
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.
AEU - International Journal of Electronics and Communications, 2018
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.
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.