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7th International Conference on Wireless Communications, networking and Mobile Computing (WiCOM)

作者： Du, Haiming Liang, Wanyong Cui, Guangzhao Zhengzhou Univ Light Ind Coll Elect & Informat Engn Zhengzhou Peoples R China

ISBN: (纸本)9781424462520

Two-way relaying is an efficient way to improve the network capacity significantly. Making use of the broadcast nature of the wireless network, physical-layer network coding (PLNC) has been evidently shown to improve the spectral efficiency further. However it has a poor performance at low SNR. In this paper, the three-node cooperative transmission is considered, where PLNC is used at the relay node. An adaptive transmission strategy is proposed to solve the issue. The transmission strategy, which is based on instantaneous channel quality, is selected to offer maximum total system capacity. The efficiency of the proposed solution is demonstrated by both analytical performance and simulations.

关键词： two-way relaying physical-layer network coding cooperative communication resouce alloaction

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NO-V2X: Non-orthogonal Multiple Access with Side Information for V2X Communications 1

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European-Alliance-for-Innovation (EAI) International Conference on Smart Grid and Innovative Frontiers in Telecommunications (SmartGIFT)

作者： Situ, Zhenhui Ho, Ivan Wang-Hei Hong Kong Polytech Univ Dept Elect & Informat Engn Hung Hom Hong Kong Peoples R China Hong Kong Polytech Univ Shenzhen Res Inst Shenzhen Peoples R China

ISBN: (数字)9783319949659

ISBN: (纸本)9783319949659;9783319949642

We study a vehicle-to-everything (V2X) communication scenario where multiple vehicles coming from different road segments converge at a road junction and exchange their information via a road side unit. The high-mobility of vehicles determines that the communication is time-critical. If conventional orthogonal multiple access (OMA) is applied, not only the orthogonal resource allocation but also the scheduling overheads will incur significant delay. In addition, orthogonal domain may not be identified within short contact time among vehicles and the road-side unit. In contrast, non-orthogonal multiple access (NOMA) can provide low-delay and reliable communication by exploiting the overlapped or collided signals. In this paper, we investigate the application of NOMA with side information in V2X communications as the Non-orthogonal V2X (NO-V2X) scheme. NO-V2X takes the advantage of side information and physical-layer network coding (PNC) to increase the decoding success rate in the uplink phase and to reduce the required transmission power in the downlink phase. Our simulation results show that NO-V2X outperforms OMA and the conventional NOMA with successive interference cancellation (SIC).

关键词： Non-orthogonal multiple access V2X communication Side information physical-layer network coding network-coded multiple access

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physical layer Implementation of network coding in Two-Way Relay networks

Physical Layer Implementation of Network Coding in Two-Way R...

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IEEE International Conference on Communications

作者： Hongjuan Yang Weixiao Meng Bo Li Gang Wang Communication Research Center Harbin Institute of Technology

ISBN: (纸本)9781457720529

network coding, which works in the network layer, is an effective technology to improve the throughput of two-way relay networks. In this paper, we compare the existing network coding schemes: traditional network coding (NC) scheme, physical-layer network coding (PNC) scheme and soft network coding (SNC) scheme, and propose a new physical layer scheme which can be seen as the implementation of network coding in two-way relay networks. Relay nodes combine the received signals from two source nodes before demodulation and channel decoding. The computational complexity and BER performance of the proposed scheme are analyzed compared with the previous schemes. Theoretical analysis show that the proposed scheme can save 50% computational cost of demodulation and channel decoding processes compared with NC scheme, meanwhile increase the power efficiency of the relay nodes in two-way relay networks significantly. Future works with the proposed scheme are also discussed.

关键词： physical layer implementation network coding Two-way relay networks physical-layer network coding Soft network coding Relay networks network coding Demodulation Bidirectional network network layer physical layer dynamic efficiency Bidirectional Scheme Trunk Node Channel Decoder received signal

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Efficient message exchange protocols exploiting state-of-the-art PHY layer

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND networkING 2017年第1期2017卷 NIL0001-NIL0014页

作者： Lemos, Joao S. Monteiro, Francisco A. Sousa, Ivo Ferreira, Filipe E. Inst Telecomunicacoes Lisbon Portugal Univ Lisbon Inst Super Tecn Lisbon Portugal ISCTE Inst Univ Lisboa Lisbon Portugal

The paper focuses on the two-way relay channel (TWRC) and the multi-way wireless network with three terminals, where all three want to exchange or share data and have to do that with the help of a relay. This paper shows how it is possible to significantly decrease the number of time slots required to exchange messages between terminals in networks based on time-division multiple access (TDMA), by taking into consideration new techniques at the physical (PHY) layer. The paper considers a PHY layer where physical-layer network coding (PLNC), multiple-input multiple-output (MIMO), and in-band "full-duplex" (IBFD) with loopback interference cancellation are all integrated, so that it is possible to significantly increase the overall throughput of the network. This is entirely attained by transferring the burden from the time domain to the spatial domain, via spatial multiplexing and by simultaneously resorting to non-orthogonal multiple access, which is the consequence of using both PLCN and IBFD. For the TWRC, it is shown that, if a massive MIMO relay is used, a simple lattice-based PLNC can be directly applied and, with typical IBFD interference cancellation amounts, a TWRC can effectively use only one time slot instead of the four needed when adopting the traditional TDMA exchange. In the case of the Y-network (i.e., with three terminals), a technique is presented that allows all the information exchange between terminals to be cut from the six time slots required in TDMA to only one time slot, provided that the information packets are not too short. The error performance of these systems is measured by means of simulation using MIMO Rayleigh fading channels.

关键词： Y-network Two-way relay channel MIMO Massive MIMO Full-duplex physical-layer network coding Packets exchange Interference suppression

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network-Coded Multiple Access with High-Order Modulations

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2017年第11期66卷 9776-9792页

作者： Pan, Haoyuan Lu, Lu Liew, Soung Chang Chinese Univ Hong Kong Dept Informat Engn Hong Kong Hong Kong Peoples R China Chinese Univ Hong Kong Inst Network Coding Hong Kong Hong Kong Peoples R China

This paper presents the first network-coded multiple access (NCMA) system prototype operated on high-order modulations up to 16-QAM. NCMA jointly exploits physical-layer network coding (PNC) and multiuser decoding (MUD) to boost throughput of multipacket reception systems. Direct generalization of the existing NCMA decoding algorithm, originally designed for BPSK, to high-order modulations, will lead to huge performance degradation. The throughput degradation is caused by the relative phase offset between received signals from different nodes. To circumvent the phase offset problem, this paper investigates an NCMA system with multiple receive antennas at the access point, referred to as MIMO-NCMA. We put forth a low-complexity symbol-level NCMA decoder that, together with MIMO, can substantially alleviate the performance degradation induced by relative phase offset. To demonstrate the feasibility and advantage of MIMO-NCMA for high-order modulations, we implemented our designs on software-defined radio. Our experimental results show that the throughput of QPSK MIMO-NCMA is double that of both BPSK NCMA and QPSK MUD at SNR = 10 dB. For higher signal-to-noise ratios at which 16-QAM can be supported, the throughput of MIMO-NCMA can be as high as 3.5 times that of BPSK NCMA. Overall, this paper provides an implementable framework for high-order modulated NCMA.

关键词： High-order modulation implementation multiple access multi-user detection network-coded multiple access physical-layer network coding

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Optimal DoF Region for the Asymmetric Two-Pair MIMO Two-Way Relay Channel

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2017年第7期65卷 1700-1711页

作者： Liu, Kangqi Tao, Meixia Yuan, Xiaojun Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China ShanghaiTech Univ Sch Informat Sci & Technol Shanghai 201210 Peoples R China

In this paper, we study the optimal degrees of freedom (DoF) region for the two-pair MIMO two-way relay channel (TWRC) with asymmetric antenna setting, where two pairs of users exchange information with the help of a common relay. Each user i is equipped with M-i antennas, for i = 1, 2, 3, 4, and the relay is equipped with N antennas. First, we prove the converse of the DoF region by using the cut-set theoremand the genie-message approach. Then, we present new transmission schemes to achieve the optimal DoF region at different antenna configurations. Due to the asymmetric data exchange, where the two users in each pair can communicate a different number of data streams, we not only need to form the network-coded symbols but also need to process the additional asymmetric data streams at the relay. This is realized through the joint design of relay compression matrix and source precoding matrices. After obtaining the optimal DoF region, we study the optimal sum DoF by solving a linear programing problem. Our DoF analysis reveals that in the asymmetric antenna setting, some antennas at certain source nodes are redundant and cannot contribute to enlarge the DoF region. It is also found that there is no loss of optimality in terms of the sum DoF by enforcing symmetric data exchange within each user pair.

关键词： Multiple-input multiple-output two-way relay channel interference alignment physical-layer network coding signal alignment degrees of freedom

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Practical Power-Balanced Non-Orthogonal Multiple Access

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2017年第10期35卷 2312-2327页

作者： Pan, Haoyuan Lu, Lu Liew, Soung Chang Chinese Univ Hong Kong Dept Informat Engn Hong Kong Hong Kong Peoples R China Chinese Acad Sci Technol & Engn Ctr Space Utilizat Beijing 100864 Peoples R China Chinese Univ Hong Kong Inst Network Coding Hong Kong Hong Kong Peoples R China

This paper is a theoretical-plus-experimental investigation of practical 5G strategies for power-balanced non-orthogonal multiple access (NOMA). By allowing multiple users to share the same time and frequency, NOMA can scale up the number of served users and increase spectral efficiency compared with existing OMA. Conventional NOMA schemes with successive interference cancellation (SIC) do not work well when users with comparable received powers transmit together. To allow power-balanced NOMA (more exactly, near power-balanced NOMA), this paper investigates a new NOMA architecture, named network-coded multiple access (NCMA). A distinguishing feature of NCMA is the joint use of physical-layer network coding (PNC) and multiuser decoding to boost NOMA throughputs. We first show that a simple NCMA architecture in which all users use the same modulation, referred to as rate-homogeneous NCMA, can achieve substantial throughput improvement over SIC-based NOMA under near power-balanced scenarios. Then, we put forth a new NCMA architecture, referred to as rate-diverse NCMA, in which different users may adopt different modulations commensurate with their relative SNRs. A challenge for rate-diverse NCMA is the design of a channel-coded PNC system. This paper is the first attempt to design channel-coded rate-diverse PNC. Experimental results on our software-defined radio prototype show that the throughput of rate-diverse NCMA can outperform the state-of-the-art rate-homogeneous NCMA by 80%. Overall, rate-diverse NCMA is a practical solution for near power-balanced NOMA.

关键词： Non-orthogonal multiple access physical-layer network coding network-coded multiple access 5G systems edge users implementation

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The Dirty MIMO Multiple-Access Channel

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IEEE TRANSACTIONS ON INFORMATION THEORY 2017年第9期63卷 6031-6040页

作者： Khina, Anatoly Kochman, Yuval Erez, Uri Tel Aviv Univ Dept Elect Engn Syst IL-69978 Tel Aviv Israel CALTECH Dept Elect Engn Pasadena CA 91125 USA Hebrew Univ Jerusalem Rachel & Selim Benin Sch Comp Sci & Engn IL-91904 Jerusalem Israel

In the scalar dirty multiple-access channel, in addition to Gaussian noise, two additive interference signals are present, each known non-causally to a single transmitter. It was shown by Philosof et al. that for strong interferences, an independent identically distributed ensemble of codes does not achieve the capacity region. Rather, a structured-codes approach was presented that was shown to be optimal in the limit of high signal-to-noise ratios, where the sum capacity is dictated by the minimal ("bottleneck") channel gain. In this paper, we consider the multiple-input multiple-output (MIMO) variant of this setting. In order to incorporate structured codes in this case, one can utilize matrix decompositions that transform the channel into effective parallel scalar dirty multiple-access channels. This approach, however, suffers from a "bottleneck" effect for each effective scalar channel and, therefore, the achievable rates strongly depend on the chosen decomposition. It is shown that a recently proposed decomposition, where the diagonals of the effective channel matrices are equal up to a scaling factor, is optimal at high signal-to-noise ratios, under an equal rank assumption. This approach is then extended to any number of transmitters. Finally, an application to physical-layer network coding for the MIMO two-way relay channel is presented.

关键词： Multiple-access channel dirty-paper coding multiple-input multiple-output channel matrix decomposition physical-layer network coding two-way relay channel

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Distributed MIMO Broadcasting: Reverse Compute-and-Forward and Signal-Space Alignment

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第1期16卷 581-593页

作者： Yang, Tao Univ Technol Sydney Global Big Data Technol Ctr Ultimo NSW 2007 Australia

We study a downlink distributed MIMO system where a central unit (CU) broadcasts messages to K' users through K distributed BSs. The CU is connected to the BSs via K independent rate-constrained fronthaul (FH) links. The distributed BSs collectively serve the users through the air. We propose a new network coding based distributed MIMO broadcasting scheme, using reverse compute-and-forward and signal-space alignment. At the CU, a network coding generator matrix is employed for pre network coding of the users' messages. The network coded messages are forwarded to the BSs, where the FH rate-constraint determines the actual number of network-coded messages forwarded to the BSs. At the BSs, linear precoding matrices are designed to create a number of bins, each containing a bunch of spatial streams with aligned signal-spaces. At each user, post physical-layer network coding is employed to compute linear combinations over the NC messages with respect to the bins, which reverses the prenetwork coding and recovers the desired messages. We derive an achievable rate of the proposed scheme based on the existence of NC generator matrix, signal-space alignment precoding matrices, and nested lattice codes. Improved rate and degrees of freedom over existing interference alignment and compress-and-forward schemes are shown. Numerical results demonstrate the performance improvement, e.g., by as much as 70% increase in throughput over benchmark schemes.

关键词： Cloud RAN CoMP MIMO distributed MIMO broadcast channel physical-layer network coding compute-and-forward interference alignment

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Joint Design of LDPC and physical-layer network coding for Bi-directional Relay System in the Presence of Insufficient Timing Synchronization

Joint Design of LDPC and Physical-Layer Network Coding for B...

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2011年无线通信与信号处理国际会议(WCSP 2011)

作者： Youyun XU Hua TIAN Wenwen LIANG Kui XU Institute of Communications Engineering PLA University of Science and TechnologyNanjing 210007 Chi Institute of Communications Engineering PLA University of Science and Technology Nanjing 210007 Ch

physical-layer network coding (PNC) has shown its power for improving the throughput effectively of the bi-directional relay system. Most of the existing PNC schemes are carried out under the assumption of perfect synchronization. In this paper, we provide some new insights into the joint design of Low-Density Parity-Check (LDPC)-coded and PNC for asynchronous bi-directional relay system with BPSK signaling. In particular, a novel LDPC and PNC joint design method is proposed for mitigating the performance degradation caused by the different timing offsets between relay and two source nodes. Simulation results show that the proposed joint design of LDPC and PNC scheme outperforms traditional method for bi-directional relay system in the presence of insufficient timing synchronization.

关键词： physical-layer network coding LDPC Bi-directional Relaying Timing Offset

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