Distributed Cooperative Transmission with Unreliable and Untrustworthy Relay Channels

Cooperative transmission is an emerging wireless communication technique that improves wireless channel capacity through multiuser cooperation in the physical layer. It is expected to have a profound impact on network performance and design. However, cooperative transmission can be vulnerable to selfish behaviors and malicious attacks, especially in its current design. In this paper, we investigate two fundamental questions Does cooperative transmission provide new opportunities to malicious parties to undermine the network performance? Are there new ways to defend wireless networks through physical layer cooperation? Particularly, we study the security vulnerabilities of the traditional cooperative transmission schemes and show the performance degradation resulting from the misbehaviors of relay nodes. Then, we design a trust-assisted cooperative scheme that can detect attacks and has self-healing capability. The proposed scheme performs much better than the traditional schemes when there are malicious/selfish nodes or severe channel estimation errors. Finally, we investigate the advantage of cooperative transmission in terms of defending against jamming attacks. A reduction in link outage probability is achieved

Game theory for collaboration in future networks

Cooperative strategies have the great potential of improving network performance and spectrum utilization in future networking environments. This new paradigm in terms of network management, however, requires a novel design and analysis framework targeting a highly flexible networking solution with a distributed architecture. Game Theory is very suitable for this task, since it is a comprehensive mathematical tool for modeling the highly complex interactions among distributed and intelligent decision makers. In this way, the more convenient management policies for the diverse players (e.g. content providers, cloud providers, home providers, brokers, network providers or users) should be found to optimize the performance of the overall network infrastructure. The authors discuss in this chapter several Game Theory models/concepts that are highly relevant for enabling collaboration among the diverse players, using different ways to incentivize it, namely through pricing or reputation. In addition, the authors highlight several related open problems, such as the lack of proper models for dynamic and incomplete information games in this area.info:eu-repo/semantics/acceptedVersio

Cooperative retransmission protocols in fading channels : issues, solutions and applications

Future wireless systems are expected to extensively rely on cooperation between terminals, mimicking MIMO scenarios when terminal dimensions limit implementation of multiple antenna technology. On this line, cooperative retransmission protocols are considered as particularly promising technology due to their opportunistic and flexible exploitation of both spatial and time diversity. In this dissertation, some of the major issues that hinder the practical implementation of this technology are identified and pertaining solutions are proposed and analyzed. Potentials of cooperative and cooperative retransmission protocols for a practical implementation of dynamic spectrum access paradigm are also recognized and investigated. Detailed contributions follow. While conventionally regarded as energy efficient communications paradigms, both cooperative and retransmission concepts increase circuitry energy and may lead to energy overconsumption as in, e.g., sensor networks. In this context, advantages of cooperative retransmission protocols are reexamined in this dissertation and their limitation for short transmission ranges observed. An optimization effort is provided for extending an energy- efficient applicability of these protocols. Underlying assumption of altruistic relaying has always been a major stumbling block for implementation of cooperative technologies. In this dissertation, provision is made to alleviate this assumption and opportunistic mechanisms are designed that incentivize relaying via a spectrum leasing approach. Mechanisms are provided for both cooperative and cooperative retransmission protocols, obtaining a meaningful upsurge of spectral efficiency for all involved nodes (source-destination link and the relays). It is further recognized in this dissertation that the proposed relaying-incentivizing schemes have an additional and certainly not less important application, that is in dynamic spectrum access for property-rights cognitive-radio implementation. Provided solutions avoid commons-model cognitive-radio strict sensing requirements and regulatory and taxonomy issues of a property-rights model

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

コグニティブネットワークとヘテロジニアスネットワークの協調によるスペクトルの効率的利用に関する研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 瀬崎 薫, 東京大学教授 浅見 徹, 東京大学教授 江崎 浩, 東京大学准教授 川原 圭博, 東京大学教授 森川 博之, 東京大学教授 相田 仁University of Tokyo(東京大学

Wireless-powered cooperative communications: protocol design, performance analysis and resource allocation

Radio frequency (RF) energy transfer technique has attracted much attention and has recently been regarded as a key enabling technique for wireless-powered communications. However, the high attenuation of RF energy transfer over distance has greatly limited the performance and applications of WPCNs in practical scenarios. To overcome this essential hurdle, in this thesis we propose to combat the propagation attenuation by incorporating cooperative communication techniques in WPCNs. This opens a new paradigm named wireless-powered cooperative communication and raises many new research opportunities with promising applications. In this thesis, we focus on the novel protocol design, performance analysis and resource allocation of wireless-powered cooperative communication networks (WPCCNs). We first propose a harvest-then-cooperate (HTC) protocol for WPCCNs, where the wireless-powered source and relay(s) harvest energy from the AP in the downlink (DL) and work cooperatively in the uplink (UL) for transmitting source information. The average throughput performance of the HTC protocol with two single relay selection schemes is analyzed. We then design two novel protocols and study the optimal resource allocation for another setup of WPCCNs with a hybrid relay that has a constant power supply. Besides cooperating with the source for UL information transmission, the hybrid relay also transmits RF energy concurrently with the AP during the DL energy transfer phase. Subsequently, we adopt the Stackelberg game to model the strategic interactions in power beacon (PB)-assisted WPCCNs, where PBs are deployed to provide wireless charging services to wireless-powered users via RF energy transfer and are installed by different operators with the AP. Finally, we develop a distributed power splitting framework using non-cooperative game theory for a large-scale WPCCN, where multiple source-destination pairs communicate through their dedicated wireless-powered relays