• Title/Summary/Keyword: Cooperative Networks

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Distance Influence on Performance of Cooperative Communication Schemes in Wireless Networks (협력 통신의 거리에 따른 성능 영향 분석)

  • Xuyen, Tran Thi;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.3
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    • pp.121-129
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    • 2010
  • In this paper, we analyze effects of positions of relays on the performance of cooperative communication networks. From this, the best relays are chosen to assist transmitting the signal to the destination or to replace the source to retransmit the signal to the destination whenever the destination incorrectly receives the signal from the source. As the results, we show the significant improvement on performance of schemes choosing best relays, which is compared to the performance of other cooperative schemes. Moreover, the simulation results that match exactly with the theoretical results prove the correctness of the analysis.

Performance Analysis of Amplify and Forward (AF)-based Cooperative Spectrum Sensing in Cognitive Radio Networks

  • Khan, Muhammad Sajjad;Koo, Insoo
    • Journal of information and communication convergence engineering
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    • v.11 no.4
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    • pp.223-228
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    • 2013
  • Cognitive radio has been recently considered a promising technology to improve spectrum utilization by enabling secondary access to licensed bands that are not used by primary users temporarily or spatially. A prerequisite to this secondary access is the lack of interference to the primary system. This requirement makes spectrum sensing a key process for cognitive radio. In this study, we consider amplify and forward (AF)-based cooperative spectrum sensing for cognitive radio networks where multiple relay nodes are utilized to amplify and forward the primary user signal for better spectrum sensing, and maximum ratio combining is used for fusion detection by a cognitive coordinator. Further, the detection probability and the bit error rate of AF-based cooperative spectrum sensing are analyzed in fading multiple cognitive relay channels. The simulation results show that the AF-based cooperative spectrum sensing scheme outperforms the conventional scheme.

Cooperative MAC Protocol Using Active Relays for Multi-Rate WLANs

  • Oh, Chang-Yeong;Lee, Tae-Jin
    • Journal of Communications and Networks
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    • v.13 no.5
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    • pp.463-471
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    • 2011
  • Cooperative communications using relays in wireless networks have similar effects of multiple-input and multiple-output without the need of multiple antennas at each node. To implement cooperation into a system, efficient protocols are desired. In IEEE 802.11 families such as a/b/g, mobile stations can automatically adjust transmission rates according to channel conditions. However throughput performance degradation is observed by low-rate stations in multi-rate circumstances resulting in so-called performance anomaly. In this paper, we propose active relay-based cooperative medium access control (AR-CMAC) protocol, in which active relays desiring to transmit their own data for cooperation participate in relaying, and it is designed to increase throughput as a solution to performance anomaly. We have analyzed the performance of the simplified AR-CMAC using an embedded Markov chain model to demonstrate the gain of AR-CMAC and to verify it with our simulations. Simulations in an infrastructure network with an IEEE 802.11b/g access point show noticeable improvement than the legacy schemes.

A Chinese Restaurant Game for Distributed Cooperative Caching in Small Cell Networks

  • Chen, Junliang;Wang, Gang;Wang, Fuxiang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.1
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    • pp.222-236
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    • 2019
  • Wireless content caching in small cell networks has recently been considered as a promising way to alleviate the congestion of the backhaul in emerging heterogenous cellular network. However, how to select files which are cached in SBSs and how to make SBSs work together is an important issue for cooperative cache research for the propose of reducing file download time. In this paper, a Cooperative-Greedy strategy (CGS) among cache-enabled small base stations (SBSs) in small cell network is proposed, in order to minimize the download time of files. This problem is formulated as a Chinese restaurant game.Using this game model, we can configure file caching schemes based on file popularity and the spectrum resources allocated to several adjacent SBSs. Both the existence and uniquencess of a Nash equilibrium are proved. In the theoretical analysis section, SBSs cooperate with each other in order to cache popular files as many as possible near UEs. Simulation results show that the CGS scheme outperforms other schemes in terms of the file-download time.

Cooperative Communication Scheme Based on channel Characteristic for Underwater Sensor Networks (수중 센서 네트워크를 위한 채널 특성기반의 협력 통신 기법)

  • Ji, Yong-Joo;Choi, Hak-Hui;Lee, Hye-Min;Kim, Dong-Seong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.6
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    • pp.21-28
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    • 2016
  • This paper presents a cooperative transmission scheme for underwater acoustic sensor networks to improve packet transmission rate and reduce energy consumption. Source node transmits duplicated information relayed by distributed antennas called a virtual antenna array. Destination node combines that information to reduce packet error rate. The suggested cooperative scheme enhances the reliability by providing high diversity gains through intermediate relay nodes to overcome the distinct characteristics of the underwater channel, such as high transmission loss, propagation delay, and ambient noises. It is suggested that the algorithm select destinations and potential relays from a set of neighboring nodes that utilize distance cost, the residual energy of each node and local measurement of the channel conditions into calculation. Simulation results show that the proposed scheme reduces average energy consumption, response time, and increases packet delivery ratio compared with the SPF(Shortest Path First) and non-cooperative scheme using OPNET Moduler.

An Entropy-based Cooperative-Aided Routing Protocol for Mobile Ad-hoc Wireless Sensor Networks (모바일 Ad-hoc 무선 센서 네트워크를 위한 엔트로피기반 협력도움 라우팅 프로토콜)

  • An, Beong-Ku;Lee, Joo-Sang
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.6
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    • pp.106-113
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    • 2008
  • In this paper, we propose an Entropy-based Cooperative-Aided Routing Protocol (ECARP) in Mobile Ad-hoc fireless Sensor Networks (MAWSN). The main contributions and features of this paper are as follows. First, the entropy-based cooperative routing protocol which is based on node mobility is proposed for supporting stable routing route construction. Second, cooperative data transmission method is used for improving data transmission ratio with the improved SNR. Third, we consider a realistic approach, in the points of view of the MAWSN, based on mobile sensor nodes as well as fixed sensor nodes in sensor fields while the conventional research for sensor networks focus on mainly fixed sensor nodes. The performance evaluation of the proposed routing protocol is performed via simulation and analysis.

A Cross-Layer Cooperative Routing Architecture for Mobile Wireless Sensor Networks (모바일 무선 센서 네트워크를 위한 Cross-Layer 협력도움 라우팅 구조)

  • Lee, Joo-Sang;An, Beong-Ku
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.1
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    • pp.141-150
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    • 2011
  • In this paper, we propose a Cross-Layer Cooperative Routing(CLCR) architecture to support transmission efficiency in mobile wireless sensor networks. The main features and contributions of the proposed architecture and method are as follows. First, the clustering which uses the location information of nodes is utilized as infrastructure. Second, a cross-layer strategy which uses the technologies of network layer, MAC layer, physical layer together to support transmission efficiency and channel efficiency for cooperative-aided routing and transmission. Third, we consider realistic approach in the view points of the mobile ad-hoc wireless sensor networks while conventional methods just consider fixed sensor network environments. The performance evaluation of the proposed method is performed via simulation using OPNET and theoretical analysis. The results of performance evaluation of the proposed CLCR show improvement of transmission efficiency by the proposed CLCR.

Cooperative Routing of Wireless Ad-hoc Networks in Rayleigh Fading Channel (레일레이 페이딩 채널에서 무선 애드 혹 네트워크의 협동라우팅)

  • Kim, Nam-Soo;An, Beong-Ku;Kim, Do-Hyeon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.3A
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    • pp.290-296
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    • 2007
  • We propose new routing scheme, Cooperative Diversity-based Routing (CDR) which utilizes the cooperative space diversity for power saving and performance enhancement of wireless ad-hoc networks. The improved performance is compared with Multi-hop Relay Routing (NRR) by analytical methods. When the required outage probability is $1\times10^{-3}$ at the destination node in ad-hoc networks with 7 nodes, we noticed that each node can save power consumption by 15.5 dB in average, by using our proposed CDR compared to MRR.

Throughput-efficient Online Relay Selection for Dual-hop Cooperative Networks

  • Lin, Yuan;Li, Bowen;Yin, Hao;He, Yuanzhi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.6
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    • pp.2095-2110
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    • 2015
  • This paper presents a design for a throughput-efficient online relay selection scheme for dual-hop multi-relay cooperative networks. Problems arise with these networks due to unpredictability of the relaying link quality and high time-consumption to probe the dual-hop link. In this paper, we firstly propose a novel probing and relaying protocol, which greatly reduces the overhead of the dual-hop link estimation by leveraging the wireless broadcasting nature of the network. We then formulate an opportunistic relay selection process for the online decision-making, which uses a tradeoff between obtaining more link information to establish better cooperative relaying and minimizing the time cost for dual-hop link estimation to achieve higher throughput. Dynamic programming is used to construct the throughput-optimal control policy for a typically heterogeneous Rayleigh fading environment, and determines which relay to probe and when to transmit the data. Additionally, we extend the main results to mixed Rayleigh/Rician link scenarios, i.e., where one side of the relaying link experiences Rayleigh fading while the other has Rician distribution. Numerical results validate the effectiveness and superiority of our proposed relaying scheme, e.g., it achieves at least 107% throughput gain compared with the state of the art solution.

Exact and Approximate Symbol Error Probability of cooperative systems with best relay selection and all participating relaying using Amplify and Forward or Decode and Forward Relaying over Nakagami-m fading channels

  • Halima, Nadhir Ben;Boujemaa, Hatem
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.1
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    • pp.81-108
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    • 2018
  • In this paper, we derive the theoretical Symbol Error Probability (SEP) of cooperative systems with best relay selection for Nakagami-m fading channels. For Amplify and Forward (AF) relaying, the selected relay offers the best instantaneous Signal to Noise Ratio (SNR) of the relaying link (source-relay-destination). In cooperative networks using Decode and Forward (DF), the selected relay offers the best instantaneous SNR of the link between the relay and the destination among the relays that have correctly decoded the transmitted information by the source. In the second part of the paper, we derive the SEP when all participating AF and DF relaying is performed. In the last part of the paper, we extend our results to cognitive radio networks where there is interference constraints : only relays that generate interference to primary receiver lower than a predefined threshold T can transmit. Both AF and DF relaying with and without relay selection are considered.