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Secure Transmission in Cooperative networks with Weak Eavesdroppers

IEEE SIGNAL PROCESSING LETTERS 2015年第10期22卷 1693-1697页

作者： Sunny, Albert Sarma, Siddhartha Kuri, Joy Indian Inst Sci Dept Elect Syst Engn Bangalore 560012 Karnataka India

In this letter, we propose a scheme to improve the secrecy rate of cooperative networks using analog network coding (ANC). ANC mixes the signals in the air;the desired signal is then separated out, from the mixed signals, at the legitimate receiver using techniques like self interference subtraction and signal nulling, thereby achieving better secrecy rates. Assuming global channel state information, memoryless adversaries and the decode-and-forward strategy, we seek to maximize the average secrecy rate between the source and the destination, subject to an overall power budget. Then, exploiting the structure of the optimization problem, we compute its optimal solution. Finally, we use numerical evaluations to compare our scheme with the conventional approaches.

关键词： analog network coding cooperative networks physical layer security power allocation weak adversaries

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Coordinated Direct and Relay Transmission with Interference Cancelation in Wireless Systems

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IEEE COMMUNICATIONS LETTERS 2011年第4期15卷 416-418页

作者： Chan Dai Truyen Thai Popovski, Petar Aalborg Univ Dept Elect Syst Aalborg Denmark

Two-way relaying schemes in wireless systems obtain throughput gain by utilizing two features (1) jointly serve two communication flows, thus implementing network coding and (2) use of information that is a priori known to cancel interference and obtain the desired signal. Based on these principles, we propose other schemes that bring throughput gains in wireless cellular systems, where relayed and direct transmissions are carried out in coordinated way. The results show that the coordinated transmission exhibit throughput improvement similar to the two-way relaying schemes.

关键词： Cooperative communications relaying analog network coding interference cancelation

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Improving the Performance of Overlapped Transmission in Wireless Ad Hoc networks

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2011年第10期29卷 1981-1990页

作者： Boppana, Surendra Shea, John M. Univ Florida Dept Elect & Comp Engn Gainesville FL USA

Multi-packet reception (MPR) has recently received attention for use in military wireless ad hoc networks because of the potential to greatly improve spatial reuse. However, MPR typically requires complicated hardware that makes it prohibitive to implement in many current military platforms. An alternative, cross-layer approach is to use an overlapped transmission technique, in which multiple transmissions can occur in the same geographical area because the communicators can use their knowledge of some of the interfering packets to recover the desired information. Examples of overlapped transmission techniques include overlapped carrier-sense multiple-access (OCSMA), physical-layer network coding, analog network coding, and Katti et al.'s COPE protocol. These techniques have much lower signal processing demands than MPR techniques and have also stimulated a lot of interest for use in military networks. Much of the previous research on overlapped transmission focuses on the physical-layer: how transmissions should be allowed to overlap, how the signals should be designed and detected, and the error probabilities under different conditions. These works tend to make optimistic assumptions about the availability of packets to perform overlapped transmission: often performance is evaluated for a simple three-node network under the assumption that traffic is always available at each of the edge nodes. In this paper, we explain why these protocols may suffer under real-world traffic conditions because of directional traffic flows and congestion control at the transport layer. We focus on how transmission control affects the performance of the OCSMA protocol. We propose modifications to the TCP parameters and the OCSMA protocol to improve the performance. We also show that OCSMA offers better fairness over the IEEE 802.11 MAC protocol in several scenarios.

关键词： overlapped transmission analog network coding cross-layer interaction multi-packet reception

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Resource Allocation for Two-Way AF Relaying with Receive Channel Knowledge

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2012年第6期11卷 2002-2007页

作者： Bagheri, Hossein Ardakani, Masoud Tellambura, Chintha Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2M7 Canada

The resource allocation problem for two sources communicating via an amplify-forward relay is studied from an outage perspective. analog network coding is considered for half-duplex nodes with perfect receiver-side channel knowledge. Under a sum power constraint, an optimal power allocation that minimizes an approximate outage probability is derived and shown to improve the performance upto 4.77 dB. A cut-set bound is also optimized to serve as a comparison reference. When such a power allocation is not feasible, two novel resource-optimized schemes, which exploit conventional one-way relaying, are proposed to reduce the outage at low multiplexing gains(1).

关键词： analog network coding convex optimization multiplexing gain resource allocation two-way relay

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Beamforming in Traffic-Aware Two-Way Relay Systems With Channel Estimation Error and Feedback Delay

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2017年第10期66卷 8807-8820页

作者： Gurjar, Devendra Singh Upadhyay, Prabhat Kumar da Costa, Daniel Benevides de Sousa, Rafael Timoteo, Jr. Indian Inst Technol Indore Discipline Elect Engn Indore 453552 Madhya Pradesh India Univ Fed Ceara Dept Comp Engn BR-60020180 Sobral CE Brazil Univ Brasilia Dept Elect Engn Cybersecur INCT Unit 6 BR-70910900 Brasilia DF Brazil

This paper presents a comprehensive performance analysis of a multi-antenna-based traffic-aware two-way relay system with unavoidable imperfections in channel state information (CSI) under Nakagami-m fading. Herein, we employ transmit/receive beamforming at source nodes and analog network coding (ANC) at the relay node in the presence of CSI imperfections due to channel estimation errors (CEE) and feedback delay. With such a practical setup, we first deduce the pertinent instantaneous end-to-end signal-to-noise ratios (SNRs) after performing partial self-interference cancellation. Then, by imposing asymmetric traffic requirements in two opposite directions, we conduct an accurate analysis of overall outage probability (OOP) of the considered system. We further derive a tight lower bound on OOP that has a simple and compact closed-form representation. Moreover, based on the asymptotic OOP expression at high SNR, we examine the achievable diversity order of the system. In addition, we acquire an upper bound expression of ergodic sum-rate (ESR) and simplify it further in useful compact form for high SNR regime. Besides, we investigate the optimization problems of relay position to minimize the OOP and to maximize the ESR. Numerical and simulation results validate our theoretical analysis and highlight the impact of CEE and feedback delay under various traffic patterns on the overall system performance.

关键词： analog network coding asymmetric traffic pattern beamforming channel estimation error feedback delay Nakagami-m fading two-way relaying

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Relay Selection for Two-Way Relaying With Amplify-and-Forward Protocols

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2011年第4期60卷 1954-1959页

作者： Song, Lingyang Peking Univ State Key Lab Adv Opt Commun Syst & Networks Sch Elect Engn & Comp Sci Beijing 100871 Peoples R China

In this paper, we propose a relay selection amplify-and-forward (RS-AF) protocol in general bidirectional relay networks with two sources and N relays. In the proposed scheme, the two sources first simultaneously transmit to all the relays, and then, a single relay with a minimum sum symbol error rate (SER) will be selected to broadcast the received signals back to both sources. To facilitate the selection process, we propose a simple suboptimal min-max criterion for relay selection, where a single relay that minimizes the maximum SER of two source nodes will be selected. Simulation results show that the proposed min-max selection has almost the same performance as the optimal selection with lower complexity. We also present a simple asymptotic SER expression and make a comparison with the conventional all-participate AF relaying scheme. The analytical results are verified through simulations. To improve the system performance, optimal power allocation (OPA) between the sources and the relay is determined based on the asymptotic SER. Simulation results indicate that the proposed RS-AF scheme with OPA yields considerable performance improvement over an equal-power-allocation scheme, particularly with a large number of relay nodes.

关键词： Amplify-and-forward (AF) protocol analog network coding relay selection two-way relaying

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Joint impact of nodes-mobility and channel estimation error on the performance of two-way relay systems

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PHYSICAL COMMUNICATION 2017年 23卷 103-113页

作者： Meshram, Ashish K. Gurjar, Devendra S. Upadhyay, Prabhat K. Indian Inst Technol Indore Discipline Elect Engn Indore 453552 Madhya Pradesh India

This paper presents the performance analysis of a two-way relay system with nodes-mobility (NM) and channel estimation errors (CEE) under time-varying Rayleigh fading. Herein, analog network coding protocol is employed at the relay node. All the participating nodes are half-duplex and equipped with single-antenna devices. Specifically, we utilize first-order Markovian model to characterize the impact of NM in the channel. Along with the NM, we also consider that the CEE may exist in practical scenarios, where nodes require to estimate the channel state information. By incorporating these factors, we first derive the instantaneous end-to-end (e2e) signal-to-noise ratios (SNRs) at two source nodes. Then, we obtain the exact closed-form expressions for distribution and density functions of the two e2e SNRs. After that, we derive the accurate expressions of various performance metrics, viz., sum-bit error rate, overall outage probability, and ergodic sum-rate. Further, to attain more insights into the considered system, we deduce the asymptotic behavior of these performance metrics. Finally, numerical and Monte-Carlo simulation results are provided to validate our theoretical analysis and to illustrate the impact of NM and CEE on the performance measures of the considered system. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Two-way relaying analog network coding Time-varying channel Nodes-mobility Imperfect channel state information

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Distributed Beamforming for Physical-Layer Security of Two-Way Relay networks

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2012年第7期60卷 3532-3545页

作者： Wang, Hui-Ming Yin, Qinye Xia, Xiang-Gen Xi An Jiao Tong Univ Sch Elect & Informat Engn Minist Educ Key Lab Intelligent Networks & Network Secur Xian 710049 Peoples R China Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA Chonbuk Natl Univ Jeonju South Korea

In this paper, we address the security of a two-way relay network in the presence of an eavesdropper, where each node is only equipped with single antenna. We propose two-phase distributed analog network coding, or distributed beamforming and power allocation to enhance the secrecy sum rate of the data exchange. In the first phase, the two terminals broadcast their information data simultaneously to all the relay nodes. In the second phase, three different security schemes are proposed: optimal beamforming, null-space beamforming, and artificial noise beamforming. In the first scheme, the objective is to achieve the maximum secrecy sum rate of the two terminals. Mathematically, the objective function is difficult to optimize. In the second scheme, we maximize the total information exchanged while we eliminate the information leakage completely, subject to the total transmission power constraint. We show that the problem has a unique and global optimum, which can be solved using bisection method. When the instantaneous channel state information of the eavesdropper is not available, we propose an artificial noise beamforming in the third scheme. We minimize the information transmission power so that the artificial noise power is maximized to eliminate information leakage, under the constraints of quality of service (QoS) required by terminals. It is a second-order convex cone programming (SOCP) problem, thus can be efficiently solved using interior point methods. Numerical results are provided and analyzed to show the properties and efficiency of the proposed designs.

关键词： analog network coding distributed beamforming physical layer security second-order cone programming secrecy rate two-way relay networks

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Performance Evaluation of In-Band Full-Duplex System Using One-Time-Slot Two-Way Relay

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IEEE SYSTEMS JOURNAL 2020年第1期14卷 510-519页

作者： Chang, Kapseok Choi, Yonghoon Elect & Telecommun Res Inst Daejeon 34129 South Korea Univ Sci & Technol Daejeon 34129 South Korea Chonnam Natl Univ Dept Elect Engn Gwangju 61186 South Korea

In-band full-duplex (IFD) two-way relay (TWR) system becomes one among the major concern for maximizing system capacity in wireless network, where one relay node and two source nodes using analog network coding (ANC) are deployed. This paper compares one-time-slot ANC (1TA) TWR, in which each node operates in IFD mode, with two-time-slot ANC (2TA) TWR, where each node is in in-band half-duplex mode. In addition, achievable sum rate of the 1TA-TWR is derived with adverse factors such as direct link interference as well as self-interference (SI), which is induced by IFD signaling. This paper proposes an iterative optimal power allocation (OPA) method to maximize the derived end-to-end sum rate, which is based on Lagrangian and Newton-Raphson algorithm under total power constraint. Numerical results elucidate the efficiency of the 1TA-TWR over the 2TA-TWR as the following: the 1TA-TWR based on the OPA becomes more and more viable than the 2TA-TWR based on existing OPA, as the relay node goes into the center of two source nodes, the link channel gain of mutual source nodes increases, and the SI channel gain approaches noise floor level.

关键词： analog network coding in-band full-duplex optimization power allocation self-interference two-way relay

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Generalized Wireless network coding Schemes for Multihop Two-Way Relay Channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第9期13卷 5132-5147页

作者： Wang, Gengkun Xiang, Wei Yuan, Jinhong Univ So Queensland Fac Hlth Engn & Sci Sch Mech & Elect Engn Toowoomba Qld 4350 Australia Univ New S Wales Fac Engn Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

Due to the overwhelming complexity of multihop transmission and intermessage interference, only a limited amount of research has been carried out in the implementation of wireless network coding (WNC) for generalized multihop two-way relay channels (MH-TRCs), let alone the generalization of multihop WNC (MH-WNC) schemes. Our recent paper has showed that the MH-WNC scheme with fixed two transmission time intervals (TTIs) was unable to always outperform conventional non-NC schemes in outage performance for the MH-TRC with an arbitrary number of nodes. In view of this fact, a generalized MH-WNC scheme with multiple TTIs is designed for the L-node K-message MH-TRC in this paper. Closed-form expressions for the upper bound of the outage probability for two prominent relaying network coding strategies (i.e., analog network coding and compute-and-forward network coding) are derived. Moreover, by investigating the relationships between the outage probability and the numbers of nodes, messages, and TTIs, we obtain an optimal MH-WNC scheme that can achieve the best outage probability and always outperform non-NC in the MH-TRC with an arbitrary number of nodes.

关键词： Multi-hop wireless network coding multi-hop two-way relay channels outage probability analog network coding compute-and-forward network coding

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