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Joint Beamforming Optimization and Power Control for Full-Duplex MIMO Two-Way Relay Channel

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2015年第3期63卷 555-566页

作者： Zheng, Gan Univ Essex Sch Comp Sci & Elect Engn Colchester CO4 3SQ Essex England Univ Luxembourg Interdisciplinary Ctr Secur Reliabil & Trust SnT Luxembourg Luxembourg

In this paper, we explore the use of full-duplex radio to improve the spectrum efficiency in a two-way relay channel where two sources exchange information through an multi-antenna relay, and all nodes work in the full-duplex mode. The full-duplex operation can reduce the overall communication to only one phase but suffers from the self-interference. Instead of purely suppressing the self-interference, we aim to maximize the end-to-end performance by jointly optimizing the beamforming matrix at the relay which uses the amplify-and-forward protocol as well as the power control at the sources. To be specific, we propose iterative algorithms and 1-D search to solve two problems: finding the achievable rate region and maximizing the sum rate. At each iteration, either the analytical solution or convex formulation is obtained. We compare the proposed full-duplex two-way relaying with the conventional half-duplex two-way relaying, a full-duplex one-way relaying and a performance upper bound. Numerical results show that the proposed full-duplex scheme significantly improves the achievable data rates over the conventional scheme.

关键词： Beamforming full-duplex radios optimization physical layer network coding two-way relay channel

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Wireless Backhaul networks With Precoding Complex Field network coding

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IEEE COMMUNICATIONS LETTERS 2015年第3期19卷 447-450页

作者： Hoc Phan Zheng, Fu-Chun Fitch, Michael Univ Reading Sch Syst Engn Reading RG6 6AH Berks England British Telecommun PLC Res & Venturing London EC1A 7AJ England

In this paper, we propose a network coding scheme for up-link wireless backhaul networks to increase the throughput while guaranteeing full diversity order. The key advance proposed is the employment of precoding complex fieldmatrices for two user and two base station backhaul networks to achieve throughput of 1 symbol/channel use while guaranteeing full diversity order for this one-way two-hop communications setting. In particular, the throughput of the considered wireless backhaul network using the proposed network coding scheme is 50% higher than that using conventional complex field network coding (CFNC) and 200% higher than that using conventional amplify-and-forward (AF) relay transmission. Importantly, the considered network obtains full diversity order, i.e., the diversity order is the same as that of the respective conventional CFNC and AF relay networks. Numerical results indicate that the simulation results of the pairwise error probability tightly converge to the asymptotic curves in the high signal-to-noise ratio.

关键词： Wireless backhaul relay networks physical layer network coding precoding complex field network coding

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Channel coding and Decoding in a Relay System Operated with physical-layer network coding

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2009年第5期27卷 788-796页

作者： Zhang, Shengli Liew, Soung-Chang Chinese Univ Hong Kong Dept Informat Engn Hong Kong Hong Kong Peoples R China Shenzhen Univ Dept Commun Engn Shenzhen Peoples R China

This paper investigates link-by-link channel-coded PNC (physical layer network coding), in which a critical process at the relay is to transform the superimposed channel-coded packets received from the two end nodes (plus noise), Y-3 = X-1 + X-2+W-3, to the network-coded combination of the source packets, S-1 circle plus S-2. This is in contrast to the traditional multiple-access problem, in which the goal is to obtain both S-1 and S-2 explicitly at the relay node. Trying to obtain S-1 and S-2 explicitly is an overkill if we are only interested in S-1 circle plus S-2. In this paper, we refer to the transformation Y-3 -> S-1 circle plus S-2 as the Channel-decoding-network-coding process (CNC) in that it involves both channel decoding and network coding operations. This paper shows that if we adopt the Repeat Accumulate (RA) channel code at the two end nodes, then there is a compatible decoder at the relay that can perform the transformation Y-3 -> S-1 circle plus S-2 efficiently. Specifically, we redesign the belief propagation decoding algorithm of the RA code for traditional point-to-point channel to suit the need of the PNC multiple-access channel. Simulation results show that our new scheme outperforms the previously proposed schemes significantly in terms of BER without added complexity.

关键词： physical layer network coding channel coding belief propagation repeat accumulate code

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Ergodic Rate Analysis of Power Allocation Schemes in Two-way Decode-and-Forward Relay Systems 82

Ergodic Rate Analysis of Power Allocation Schemes in Two-way...

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IEEE 82nd Vehicular Technology Conference (VTC Fall)

作者： Chen, Chen Yang, Yehua Bai, Lin Jin, Ye Choi, Jinho Peking Univ State Key Lab Adv Opt Commun Syst & Networks Beijing Peoples R China Beihang Univ Sch Elect & Informat Engn Beijing Peoples R China Gwangju Inst Sci & Technol Sch Informat & Commun Gwangju South Korea

ISBN: (纸本)9781479980918

Most previous researches on the rate analysis of the power allocation (PA) schemes in two-way decode-and-forward (DF) relay systems typically focus on maximizing the instantaneous objective rates. However, the ergodic rate analysis of the optimized rates is not well considered. In this paper, we investigate the ergodic rates of the PA schemes in a two-way DF relay system, where the physical-layer network coding (PNC) protocol is adopted. Specifically, under a total power constraint, we consider three heuristic PA schemes, in which the optimization objectives are: 1) maximizing the sum rate;2) maximizing the sum rate with an additional rate fairness constraint;and 3) maximizing the minor rate of the two directions of the system. The cumulative distribution functions (CDFs) of the equivalent system SNR are approximately obtained and the analytical expressions for the calculations of the ergodic rates are theoretically derived. Numerical results show that the derived analytical rates are converged to the simulated results in high SNR regions.

关键词： Two-way relay system physical layer network coding power allocation ergodic rate

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Relay Antenna Selection for V2V Communications using PLNC over Cascaded Fading Channels 11

Relay Antenna Selection for V2V Communications using PLNC ov...

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11th IEEE International Wireless Communications and Mobile Computing Conference (IEEE IWCMC)

作者： Ata, Serdar Ozgur Altunbas, Ibrahim Istanbul Tech Univ Dept Elect & Commun Engn Istanbul Turkey Sci & Technol Res Council Turkey Informat & Informat Secur Res Ctr Kocaeli Turkey

ISBN: (纸本)9781479953448

This work focuses on the relay antenna selection problem in a Vehicle-to-Vehicle (V2V) communication system employing physical layer network coding (PLNC) with amplifyand-forward (AF) scheme on a multi-antenna relay under doubleNakagami-m fading channel conditions. We obtain lower and upper bounds of end-to-end signal-to-noise ratio (E2E-SNR) and their cumulative density functions (CDF). Employing the CDFs, performance of the system is evaluated in terms of outage probabilities. We analyze asymptotic diversity order of the system and express it as a function of number of relay antennas and channels' parameters. Finally the analytical results are verified by the simulations.

关键词： Vehicle-to-Vehicle Communication physical layer network coding relay antenna selection cascaded Nakagami-m channel

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Two-way OFDM-based Nonlinear Amplify-and-Forward Relaying: Power Allocation

Two-way OFDM-based Nonlinear Amplify-and-Forward Relaying: P...

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European Conference On networks And Communications (EuCNC)

作者： Simmons, David E. Coon, Justin P. Univ Oxford Dept Engn Sci Parks Rd Oxford OX1 3PJ England

ISBN: (纸本)9781467373593

We consider the problem of allocating power among the nodes of a two-way amplify-and-forward OFDM-based relay network employing physical layer network coding. Because of the large peak-to-average power ratios that occur at the relay of such systems, we deem it important to understand the negative effects that nonlinear transmissions might have at the relay. Thus, we assume that the relay is subject to its own independent transmit power constraint, beyond which nonlinear distortion is introduced. We consider two power allocation problems: 1) the transmit power budget of the communicating nodes is independent of the relay's transmit power, 2) the relay's transmit power is included within the total power budget of the network. For the former, a closed form solution is obtained. For the latter, the problem is shown to be non-convex in its standard form. By applying a substitution, we show that it can be converted into a convex problem. Numerical results are provided to demonstrate the efficacy of our methods. Finally, a discussion is included to give further insight into how our power allocation scheme behaves as a function of the network's asynunetry.

关键词： Relay amplify-and-forward performance nonlinear amplifier physical layer network coding PNC power allocation

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DFE FOR FREQUENCY SELECTIVE PNC CHANNELS USING AF 11

DFE FOR FREQUENCY SELECTIVE PNC CHANNELS USING AF

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11th IEEE International Conference on Wireless and Mobile Computing, networking and Communications (WiMob)

作者： Ahmed, Alaa H. Tsimenidis, Charalampos C. Neasham, Jeffrey Sharif, Bayan S. Newcastle Univ Sch Elect & Elect Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England

ISBN: (纸本)9781467377010

High speed transmission of information suffers inevitably by intersymbol interference (ISI) induced by multipath propagation over frequency selective channels. ISI has been a major obstacle preventing the successful implementation of physical layer network coding (PLNC) systems in these environments. Another major obstacle is the high computational complexity of existing algorithms dealing with ISI, which is a determining factor in the design of relay nodes. In this paper, we propose a novel and computationally efficient decision feedback equalizer structure that is utilized at the end node and in conjunction with a simple amplify and forward (AF) technique employed at the relay. We derive the optimal equations for the decision feedback equalizer (DFE) coefficients and evaluate the end-to-end bit error rate performance in frequency selective channels, and provide both analytical and numerical simulation results that demonstrate the feasibility of the proposed approach under realistic channel conditions. The obtained results show that E2E performance is dominated by the channel with most severe frequency selectivity.

关键词： physical layer network coding frequency selective channels amplify and forward decision feedback equalizer

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A New Channel coding network coding Scheme for Two-Way Relay

A New Channel Coding Network Coding Scheme for Two-Way Relay

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Science and Information Conference (SAI)

作者： Liu, William Imperial Coll London Dept Elect & Elect Engn London England

ISBN: (纸本)9781479985470

In this paper, after a brief review of all the channel coded physical layer network coding (PNC) schemes, we introduce the definition of compatibility of channel code and lattice code, and provide a methodology with which the standard joint channel coding lattice coding (JCCNC) scheme can be applied to general types of pulse amplitude modulation (PAM) and quadrature amplitude modulation (QAM) modulation systems. We also propose a new scheme for two-way relay systems called lattice decoding joint channel coding network coding scheme (LDJCCNC). Compared with the existing schemes, this new scheme has the advantage of less complexity, not requiring the channel information, and being able to be conveniently applied to general types of PAM and QAM modulation systems. Simulation results show that this new channel coded PNC scheme has good performance and its performance is better than the standard channel coded network coding scheme when the channel information is unknown or misestimated.

关键词： channel coding Compute-and-Forward lattice decoding LDPC code physical layer network coding two-way relay

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Low-complexity LDPC Decoder for physical layer network Coded Multi-way Wireless Relay Systems 10

Low-complexity LDPC Decoder for Physical Layer Network Coded...

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10th IEEE International Conference on Industrial and Information Systems (ICIIS)

作者： Balasuriya, Nuwan Wavegedara, Chandika B. Univ Moratuwa Dept Elect & Telecommun Engn Moratuwa Sri Lanka

ISBN: (纸本)9781479918768

Recently, in multi-way relay systems employing physical-layer network coding (PNC), channel condition-based pair selection for pairwise information exchange has drawn increased attention as it provides improved performance over the alternative approaches such as round-robin scheduling of node pairs. With pairwise information exchange, there is additional time diversity available due to transmission of the same coded information block of most of the nodes twice in two adjacent time slots. This additional time diversity can be exploited to further enhance the system performance by means of joint channel decoding-network coding. To this end, a joint belief propagation (BP)-based channel decoding-network coding algorithm was proposed by us in [9] for the relay node of low density parity check (LDPC)-coded multi-way relay systems. Even though the algorithm of [9] offers much superior performance over separate channel decoding, it is highly computational expensive and may not be suitable for applications in wireless sensor networks. Alternatively, bit-flipping (BF)-based LDPC decoding can be adopted at much lower computational complexity. In this paper, we develop a low complexity joint bit-flipping (BF) based channel decoding and network coding algorithm for LDPCbased multi-way relay systems. The BER performance of the proposed algorithm is investigated using computer simulation for two commonly used LDPC codes. The simulation results demonstrate that superior BER performance can be achieved using the proposed joint decoding algorithm over separate and independent bit-flipping-based LDPC channel decoding at the relay. The simulation results also verify that our proposed algorithm is capable of harnessing the aforesaid additional time diversity available. Though the performance of the proposed joint decoding algorithm is inferior to the BP-based algorithm of [9], due to its low computationally complexity, this algorithm may be appealing for applications in relay nodes wit

关键词： Multi-way relay channel physical layer network coding low density parity check codes (LDPC) bit-flipping decoder

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Performance of physical layer network coding in a Frequency-selective Fading Channel

Performance of Physical Layer Network Coding in a Frequency-...

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20th IEEE Symposium on Personal, Indoor and Mobile Radio Communications

作者： Gacanin, Haris Adachi, Fumiyuki Tohoku Univ Grad Sch Engn Dept Elect & Commun Engn Sendai Miyagi 980 Japan

ISBN: (纸本)9781424451234

Wireless communications are characterized by a multipath propagation that is suitable for application of network coding (NC) to improve the network performance. In particular, a physical layer network coding (PNC) is a promising technique to further improve network capacity for bi-directional information exchange between pairs of end users assisted by a relay terminal. In this paper, we present the performance of bi-directional transmission with PNC in a multipath channel. We introduce the use of frequency domain equalization (FDE) with orthogonal frequency division multiplexing (OFDM) and single carrier (SC) transmission to cope with the channel distortion. The equalization weights based on minimum mean square error (MMSE) criteria required for SC-FDE signaling are derived.

关键词： physical layer network coding frequency-selective fading OFDM SC-FDE

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