Optimal sensing period in cooperative relay cognitive radio networks

( Shibing Zhang ),( Xin Guo ),( Xiaoge Zhang ),( Gongan Qiu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

Cognitive radio is an efficient technique to improve spectrum efficiency and relieve the pressure of spectrum resources. In this paper, we investigate the spectrum sensing period in cooperative relay cognitive radio networks; analyze the relationship between the available capacity and the signal-to-noise ratio of the received signal of second users, the target probability of detection and the active probability of primary users. Finally, we derive the closed form expression of the optimal spectrum sensing period in terms of maximum throughput. We simulate the probability of false alarm and available capacity of cognitive radio networks and compare optimal spectrum sensing period scheme with fixed sensing period one in these performance. Simulation results show that the optimal sensing period makes the cognitive networks achieve the higher throughput and better spectrum sensing performance than the fixed sensing period does. Cooperative relay cognitive radio networks with optimal spectrum sensing period can achieve the high capacity and steady probability of false alarm in different target probability of detection. It provides a valuable reference for choosing the optimal spectrum sensing period in cooperative relay cognitive radio networks.

Optimal sensing period in cooperative relay cognitive radio networks

Zhang, Shibing,Guo, Xin,Zhang, Xiaoge,Qiu, Gongan Korean Society for Internet Information 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

Cognitive radio is an efficient technique to improve spectrum efficiency and relieve the pressure of spectrum resources. In this paper, we investigate the spectrum sensing period in cooperative relay cognitive radio networks; analyze the relationship between the available capacity and the signal-to-noise ratio of the received signal of second users, the target probability of detection and the active probability of primary users. Finally, we derive the closed form expression of the optimal spectrum sensing period in terms of maximum throughput. We simulate the probability of false alarm and available capacity of cognitive radio networks and compare optimal spectrum sensing period scheme with fixed sensing period one in these performance. Simulation results show that the optimal sensing period makes the cognitive networks achieve the higher throughput and better spectrum sensing performance than the fixed sensing period does. Cooperative relay cognitive radio networks with optimal spectrum sensing period can achieve the high capacity and steady probability of false alarm in different target probability of detection. It provides a valuable reference for choosing the optimal spectrum sensing period in cooperative relay cognitive radio networks.

Localization and Privacy Preservation in Cognitive Radio Networks

Xu Zhang,Xia Ying,Hongrui Mao,Hae Young Bae 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1

Cognitive Radio Networks (CRNs) has been considered as a key technology for future wireless communications and mobile computing. Localization of primary user is crucial in enabling several key capabilities in CRNs. In this paper, we present a survey of representative methods dealing with user localization and location privacy preservation issues and propose a taxonomy that summarizes the state-of-the-art. The objective is to provide a comprehensive analysis and guide of existing efforts around localization and location privacy preservation in cognitive radio network. This survey is intended to help researchers in quickly understanding existing works and challenges, and possible improvements to bring.

Performance Analysis of Cognitive Relay Networks with Simple Relay Selection

Jemin Lee,Gosan Noh,Hano Wang,Sungmook Lim,Eunho Choi,Daesik Hong 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

This paper evaluates the outage probability of cognitive relay networks while adhering to the interference constraint on the primary user, the limited amount of interference which the primary user can tolerate. In the relaying transmission, the relay selection critically affects the performance of relaying transmission and the conventional relay selection criteria are not suitable in cognitive relay networks because of the interference constraint. Hence, the relay selection criterion for cognitive relay networks is proposed and using it, we derive the outage probability. Based on the analysis, we also define the conditions that the relaying transmission achieves better performance in outage probability than the direct transmission. Finally, it is verified that the distance ratio of interfering link to relaying link, the interference threshold as well as the target data rate affect the superiority to relaying transmission compared to the direct transmission in cognitive relay networks.

무선 인지 셀룰러 망에서 자원예측에 의한 가드채널 할당기법의 성능개선

이진이 ( Jin Yi Lee ) 한국항행학회 2012 韓國航行學會論文誌 Vol.16 No.5

본 논문에서는 셀룰러 기반 무선 인지망에서 핸드오프 호를 위한 가드채널할당기법(guard channel scheme)의 자원이용률의 저하를 개선하기 위해 무선인지 기술을 사용하여 자원 이용률을 향상시키면서, 무선 인지망의 부 사용자(cognitive radio user) 손실률을 줄이는 방법을 제안한다. 제안한 방법에서는 핸드오프 호의 전용채널(guard channel)을 부 사용자가 이용하도록 하고, MMOSPRED(Multi-Media One Step Prediction)기법으로 핸드오프 호의 발생을 예측한 다음, 핸드오프 호가 발생하면 핸드오프 호의 전용채널을 넘겨주고, 부 사용자는 예약된 자원으로 스펙트럼 핸드오프를 하여 서비스를 완료 하도록 한다. 시뮬레이션을 통하여, 제안한 기법의 자원 이용률과 부 사용자의 손실률에 대한 성능이 기존의 가드채널 할당기법과 모바일의 이동성을 예측하지 않은 채널할당기법 보다 우수함을 보인다. In this paper, we propose a scheme for improving not only the utilization of frequency bands in the guard channel scheme but also the dropping rate of cognitive radio user in the wireless cognitive radio-based cellular network. The proposed scheme enables cognitive radio users to utilize the guard channel for servicing only handoff calls in normal times, but cognitive radio users must vacate the frequency channel when handoff call appearing. At this time our scheme ensures their seamless services for cognitive radio users, by predicting handoff call`s appearance by MMOSPRED (Multi-Media One Step Prediction) method and then reserving the demanded channels for spectrum handoff calls. Our simulations show that our scheme performs better than other schemes; GCS(Guard Channel Scheme) and a scheme without prediction in terms of cognitive users call`s dropping rate and resource utilization efficiency.

Analysis of Channel Access Delay in CR-MAC Protocol for Ad Hoc Cognitive Radio Wireless Sensor Networks without a Common Control Channel

( Gyanendra Prasad Joshi ),( Seung Yeob Nam ),( Srijana Acharya ),( Sung Won Kim ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.3

Ad hoc cognitive radio wireless sensor networks allow secondary wireless sensor nodes to recognize spectrum opportunities and transmit data. Most existing protocols proposed for ad hoc cognitive radio wireless sensor networks require a dedicated common control channel. Allocating one channel just for control packet exchange is a waste of resources for channel-constrained networks. There are very few protocols that do not rely on a common control channel and that exchange channel-negotiation control packets during a pre-allocated time on the data channels. This, however, can require a substantial amount of time to access the channel when an incumbent is present on the channel, where the nodes are intended to negotiate for the data channel. This study examined channel access delay on cognitive radio wireless sensor networks that have no dedicated common control channel.

Connectivity Analysis of Cognitive Radio Ad-hoc Networks with Shadow Fading

( Le The Dung ),( Beongku An ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.9

In this paper, we analyze the connectivity of cognitive radio ad-hoc networks in a log-normal shadow fading environment. Considering secondary user and primary user`s locations and primary user`s active state are randomly distributed according to a homogeneous Poisson process and taking into account the spectrum sensing efficiency of secondary user, we derive mathematical models to investigate the connectivity of cognitive radio ad-hoc networks in three aspects and compare with the connectivity of ad-hoc networks. First, from the viewpoint of a secondary user, we study the communication probability of that secondary user. Second, we examine the possibility that two secondary users can establish a direct communication link between them. Finally, we extend to the case of finding the probability that two arbitrary secondary users can communicate via multi-hop path. We verify the correctness of our analytical approach by comparing with simulations. The numerical results show that in cognitive radio ad-hoc networks, high fading variance helps to remarkably improve connectivity behavior in the same condition of secondary user`s density and primary user`s average active rate. Furthermore, the impact of shadowing on wireless connection probability dominates that of primary user`s average active rate. Finally, the spectrum sensing efficiency of secondary user significantly impacts the connectivity features. The analysis in this paper provides an efficient way for system designers to characterize and optimize the connectivity of cognitive radio ad-hoc networks in practical wireless environment.

Complexity based Sensing Strategy for Spectrum Sensing in Cognitive Radio Networks

( Kewen Huang ),( Yimin Liu ),( Yuanquan Hong ),( Junsheng Mu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.9

Spectrum sensing has attracted much attention due to its significant contribution to idle spectrum detection in Cognitive Radio Networks. However, specialized discussion is on complexity-based sensing strategy for spectrum sensing seldom considered. Motivated by this, this paper is devoted to complexity-based sensing strategy for spectrum sensing. Firstly, three efficiency functions are defined to estimate sensing efficiency of a spectrum scheme. Then a novel sensing strategy is proposed given sensing performance and computational complexity. After that, the proposed sensing strategy is extended to energy detector, Cyclostationary feature detector, covariance matrix detector and cooperative spectrum detector. The proposed sensing strategy provides a novel insight into sensing performance estimation for its consideration of both sensing capacity and sensing complexity. Simulations analyze three efficiency functions and optimal sensing strategy of energy detector, Cyclostationary feature detector and covariance matrix detector.

Transport Protocols in Cognitive Radio Networks: A Survey

( Xiaoxiong Zhong ),( Yang Qin ),( Li Li ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

Cognitive radio networks (CRNs) have emerged as a promising solution to enhance spectrum utilization by using unused or less used spectrum in radio environments. The basic idea of CRNs is to allow secondary users (SUs) access to licensed spectrum, under the condition that the interference perceived by the primary users (PUs) is minimal. In CRNs, the channel availability is uncertainty due to the existence of PUs, resulting in intermittent communication. Transmission control protocol (TCP) performance may significantly degrade in such conditions. To address the challenges, some transport protocols have been proposed for reliable transmission in CRNs. In this paper we survey the state-of-the-art transport protocols for CRNs. We firstly highlight the unique aspects of CRNs, and describe the challenges of transport protocols in terms of PU behavior, spectrum sensing, spectrum changing and TCP mechanism itself over CRNs. Then, we provide a summary and comparison of existing transport protocols for CRNs. Finally, we discuss several open issues and research challenges. To the best of our knowledge, our work is the first survey on transport protocols for CRNs.

A Sensing Node Selection Scheme for Energy-Efficient Cooperative Spectrum Sensing in Cognitive Radio Sensor Networks

Fanhua Kong(공판화),Zilong Jin(김자룡),Jinsung Cho(조진성) Korean Institute of Information Scientists and Eng 2016 정보과학회논문지 Vol.43 No.1

Cognitive radio technology can allow secondary users (SUs) to access unused licensed spectrums in an opportunistic manner without interfering with primary users (PUs). Spectrum sensing is a key technology for cognitive radio (CR). However, few studies have examined energy-efficient spectrum sensing in cognitive radio sensor networks (CRSNs). In this paper, we propose an energy-efficient cooperative spectrum sensing nodes selection scheme for cluster-based cognitive radio sensor networks. In our proposed scheme, false alarm probability and energy consumption are considered to minimize the number of spectrum sensing nodes in a cluster. Simulation results show that by applying the proposed scheme, spectrum sensing efficiency is improved with a decreased number of spectrum sensing nodes. Furthermore, network energy efficiency is guaranteed and network lifetime is substantially prolonged.