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On the relay selection for cooperative wireless networks with physical-layer network coding

WIRELESS networkS 2012年第6期18卷 653-665页

作者： Zheng, Zeyu Fu, Shengli Lu, Kejie Wang, Jianping Chen, Biao Univ N Texas Dept Elect Engn Denton TX 76207 USA City Univ Hong Kong Dept Comp Sci Hong Kong Hong Kong Peoples R China Univ Puerto Rico Dept Elect & Comp Engn Mayaguez PR 00681 USA Univ Macau Fac Sci & Technol Dept Comp & Informat Sci Macau Peoples R China

In this paper, we investigate a large cooperative wireless network with relay nodes, in which cooperation is enabled through physical-layer network coding (PLNC). Specifically, we study the impact of the relay selection on the network capacity with power constraints in two scenarios. First, we consider the basic PLNC model (a.k.a., the ARB model), in which one pair of source nodes (A, B) exchange messages via a selected relay node (R). Given the power constraint, we derive the optimal relay selection and power allocation that maximize the sum capacity, defined as the summation of the capacity for two source-destination channels. Based on results obtained above, we then consider a more general scenario with multiple pairs of source nodes. Assuming the constant power constraint, we derive the upper bound of the minimal sum capacity of any source pair. The optimal power allocation among multiple source pairs is also derived. To validate these theoretical results, we also provide two relay selection strategies: a modified optimal relay assignment strategy and a novel middle point strategy for maximizing the minimal sum capacity of any source pair.

关键词： physical-layer network coding The ARB model Relay selection Power constraints Sum capacity

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On Symbol Mapping for Binary physical-layer network coding with PSK Modulation

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2012年第1期11卷 21-26页

作者： Noori, Moslem Ardakani, Masoud Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2M7 Canada

In a system employing physical-layer network coding, the superimposed constellation at the relay may have ambiguity where one received signal is associated with more than one possible combination of users' data. We find the necessary and sufficient condition on a user bit mapping which removes this ambiguity for phase shift keying modulation. Further, we introduce the concept of semi-Gray mapping which improves the system BER performance and achievable rate. The necessary and sufficient condition of having a semi-Gray mapping is also found. Interestingly, the widely used binary reflected Gray mapping does not satisfy the semi-Gray mapping condition resulting in a poorer performance compared to our proposed semi-Gray scheme.

关键词： physical-layer network coding PSK modulation symbol mapping minimum Euclidean distance

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Throughput Gain of Random Wireless networks with physical-layer network coding

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Tsinghua Science and Technology 2012年第2期17卷 161-171页

作者： Xican Yang Jian Li Changliang Xie Li Li Department of Electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Information Mechanical and Electronic EngineeringShanghai Normal UniversityShanghai 200235China

This study analyzes the impact of physical-layer network coding （PNC） on the throughput of a large random wireless network, including one-dimensional and two-dimensional networks. Three different transmission schemes, （1） a traditional flow-based scheme, （2） a network coding scheme, and （3） the PNC scheme are compared to show that the PNC scheme improves wireless network throughput by a constant factor without changing the scaling law compared to the traditional flow-based and network coding schemes. Furthermore, PNC can reduce the effect of interference for the one-dimensional networks, and has a tighter throughput bound for the two-dimensional network.

关键词： physical-layer network coding throughput delay

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Effective capacity of two way relay channels under retransmission schemes

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2020年 124卷 153321-153321页

作者： Bouteggui, Mokhtar Merazka, Fatiha Kurt, Gunes Karabulut USTHB Univ Elect & Comp Engn Fac Dept Telecommun LISIC Lab Algiers 16111 Algeria Istanbul Tech Univ Dept Elect & Commun Engn TR-34469 Istanbul Turkey

The important role provided by relays in communication networks is indisputable as they improve the transmission robustness by the retransmission schemes. In this paper, the effective capacity of two-way relay channels (TWRCs) in presence of retransmission schemes is investigated. We derive the effective capacity for the two phase scheme referred to as complex field network coding (CFNC). Based on the obtained results, we propose a hybrid scheme combining the traditional scheme (TS) and the CFNC, denoted by JTCNC. Automatic repeat request (ARQ) is used as the retransmission scheme, while the recent framework of the recurrence relation approach is adopted for the effective capacity. The asymmetric scenario, in which users may have different average signal to noise ratios (SNR) at the relay in the uplink and the downlink, is considered. Results obtained in this paper show that CFNC achieves the maximum value of 92 b/Hz/s at high SNR. However, it suffers from performance degradation when the uplink channel has low SNR. This problem is addressed in our proposed JTCNC scheme. The effective capacity for each user has also been derived and the impact of each source by the other sources is also investigated. (C) 2020 Elsevier GmbH. All rights reserved.

关键词： Automatic repeat request Effective capacity Effective bandwidth network coding physical-layer network coding Recurrence relation approach Retransmissions

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Transmit power minimisation for full-duplex two-way relaying systems with asymmetric packet-rates and quality-of-service requirements

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IET COMMUNICATIONS 2020年第13期14卷 2098-2109页

作者： Qian, Chong Ji, Xiaodong Cao, Zhanghua Li, Wenhua Nantong Univ Sch Informat Sci & Technol Nantong 226019 Peoples R China Wenluo Corp Elect Sci & Technol Jiangsu Nantong 226019 Peoples R China

This study solves the transmit power minimisation problem subject to a target quality-of-service constraint of a full-duplex (FD) two-way decode-and-forward relaying system with asymmetric packet-rates, where the two-way relaying system can operate in two different styles, i.e. half-duplex sources with full-duplex relaying (HDS-FDR) and full-duplex sources with full-duplex relaying (FDS-FDR) styles. For the FDS-FDR style, the relay node can use two strategies to handle the received signals from the sources, namely, physical-layer network coding (PNC) and physical-layer superposition coding (PSC), both of which are referred to as FDS-FDR-PNC and FDS-FDR-PSC styles, respectively. By transforming the transmit power minimisation problem into a two-stage problem, optimum power control (OPC) techniques are developed for the HDS-FDR, FDS-FDR-PNC and FDS-FDR-PSC styles, respectively, giving closed-form solutions for individual transmit power at the relay and the sources. Computer simulations are conducted and the results validate the proposed OPC techniques. It is shown that the FDS-FDR-PNC style performs best in terms of energy saving when the two sources' packet-rates are moderately asymmetric or symmetric. For the case that the packet-rates are strongly asymmetric, the FDS-FDR-PSC style can save more energy than the other two styles.

关键词： relay networks (telecommunication) power control network coding quality of service telecommunication control decode and forward communication HDS-FDR FDS-FDR-PSC style individual transmit power FDS-FDR-PNC style asymmetric packet-rates quality-of-service requirements transmit power minimisation problem subject target quality-of-service constraint half-duplex sources full-duplex sources full-duplex relaying styles FDS-FDR style relay node physical-layer superposition coding optimum power control techniques full-duplex two-way decode-and-forward relaying system physical-layer network coding

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Cooperative Communication with physical-layer network coding in Cognitive Radio network

Cooperative Communication with Physical-layer Network Coding...

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2nd International Conference on Instrumentation and Measurement, Computer, Communication and Control (IMCCC)

作者： Xu, Zhongwei Hou, Xiaoyun Wei, Hao Nanjing Univ Posts & Telecommun Inst Signal Proc & Transmiss Nanjing 210003 Jiangsu Peoples R China

ISBN: (纸本)9780769549354

Cognitive radio technology is a promising technology to solve the inefficiency problem of the usage of spectrum, and with the help of the cooperative communication technology, the system can obtain more performance. This paper proposes a cooperative communication strategy based on physical-layer network coding (PNC) to work out the difficulty that the primary cannot communicate, which the secondary user can also access the spectrum. Meanwhile, we also discuss the power allocation scheme and relay selection strategy to maximum the system capacity. With amplify forward (AF), the secondary forwards the signal after orthogonal zing the single of the primary user and the secondary user. Simulation results showed that, with the cooperation of the secondary user, the primary user can communicates efficiently;the secondary user transmits availably as well. The system achieves the best performance by the power allocation scheme and relay selection strategy.

关键词： cognitive radio physical-layer network coding cooperative communication

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Joint LDPC and physical-layer network coding for Two-way Relay Channels with Different Carrier Frequency Offsets

Joint LDPC and Physical-Layer Network Coding for Two-way Rel...

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4th International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Liang Wenwen Chen Yande Xu Kui Tian Hua Xu Youyun PLA Univ Sci & Technol Inst Commun Engn Nanjing 210007 Jiangsu Peoples R China

ISBN: (纸本)9781467358293;9781467358309

In practical two-way relay channels, different carrier frequency offsets of physical-layer network coding is a very common situation, which can bring serious performance loss of wireless communication systems. Most of the existing joint channel code and PNC schemes are carried out under the assumption of perfect synchronization. This paper we propose a new joint scheme of Low-Density Parity-Check (LDPC)-coded and physical-layer network coding, and different carrier frequency offsets is considered. Simulation results highlight that the proposed joint design of LDPC and physical-layer network coding scheme outperforms traditional method for in practical two-way relay channels when different carrier frequency offsets is considered.

关键词： Two-way Relay Channels Different Carrier Frequency Offsets physical-layer network coding LDPC

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OFDM Modulated PNC in V2X Communication: An ICI-Aware Approach Against CFOs and Time-Frequency-Selective Channels

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IEEE ACCESS 2019年 7卷 4880-4897页

作者： Situ, Zhenhui Ho, Ivan Wang-Hei Wang, Taotao Liew, Soung Chang Chau, Sid Chi-Kin Hong Kong Polytech Univ Dept Elect & Informat Engn Hong Kong Peoples R China Hong Kong Polytech Univ Res Inst Sustainable Urban Dev Hong Kong Peoples R China Shenzhen Univ Coll Informat Engn Shenzhen 518060 Peoples R China Chinese Univ Hong Kong Dept Informat Engn Hong Kong Peoples R China Australian Natl Univ Res Sch Comp Sci Canberra ACT 0200 Australia

This paper studies the application of physical-layer network coding (PNC) in vehicleto-everything communications to accommodate the time-critical nature of vehicular ad-hoc networks (VANETs). The idea can theoretically reduce the transmission latency by 50%, thus alleviating the short contact time issues caused by high-speed vehicle motion. Conventional studies of PNC primarily considered static networks. In highly mobile networks like VANETs, the carrier frequency offsets (CFOs) due to high-speed motion will lead to inter-carrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) systems. Moreover, the vehicular environment with time-frequency-selective channels further undermines accurate channel estimation for multiple users. It is also worth noting that the CFO that exists in OFDM modulated PNC cannot be completely eliminated through CFO tracking and equalization as in conventional point-to-point transmissions. These critical issues can significantly increase the bit error rate at the receiver. To address these challenges, this paper proposes an ICI-aware approach that jointly achieves accurate channel estimation, signal detection, and channel decoding. We express the channel estimation and detection and decoding as two optimization problems and resolve them with the expectation-maximization algorithm and the belief propagation algorithm, respectively. The proposed approach can efficiently mitigate the negative effect of ICI by exploiting both pilot and data tones in channel estimation, detection, and decoding. Both simulation and experiment are conducted to evaluate the proposed approach, and the results reveal that the proposed algorithm outperforms the benchmark that simply treats ICI as Gaussian noise.

关键词： V2X communication physical-layer network coding time-frequency-selective channel inter-carrier interference

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Signal technique for friend or foe detection of intelligent malicious user in cognitive radio network

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INTERNATIONAL JOURNAL OF AD HOC AND UBIQUITOUS COMPUTING 2019年第1期32卷 29-42页

作者： Sabuj, Saifur Rahman Hamamura, Masanori BRAC Univ Dept Elect & Elect Engn Dhaka 1212 Bangladesh Kochi Univ Technol Grad Sch Engn Kami 7828502 Japan

In cognitive radio networks, security issues arise when intelligent malicious users can attack and decrease the permitted channel for unlicensed users (secondary users). In this paper, we propose a novel scheme, based on friend or foe (FoF) detection technique with physical layer network coding, to enable discrimination between secondary users and intelligent malicious users. Theoretical expressions are derived for probabilities of detection of secondary user, miss detection, and false alarm. In addition, the effectiveness of the proposed approach is evaluated by theoretical analysis and Monte Carlo simulation. Furthermore, an algorithm is proposed for distinguishing between secondary user and intelligent malicious user. Finally, based on the outcome of simulation of probabilities and normalised cross-correlation, it is determined that the proposed scheme outperforms in terms of orthogonal frequency-division multiplexing (OFDM) signal compared with quadrature phase-shift keying (QPSK) signal over cognitive radio network.

关键词： cognitive radio network friend or foe detection physical-layer network coding cross-correlation

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Joint decoder for network and channel coded multi-way relay systems with MPSK modulation

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IET COMMUNICATIONS 2019年第15期13卷 2273-2279页

作者： Balasuriya, Nuwan Wavegedara, Chandika B. Univ Moratuwa Dept Elect & Telecommun Engn Moratuwa Sri Lanka HCT Abu Dhabi U Arab Emirates

In wireless sensor networks, multi-way relaying is a very common network configuration, where multiple nodes exchange information via a single relay over uncorrelated fading channels. In such configuration, node pair-wise communication together with physical-layer network coding (PNC) at the relay node provides a good trade-off between spectral efficiency and error performance. A joint channel decoding-PNC algorithm employed at the relay can further improve the bit error rate performance. This study proposes an improved joint channel decoding-PNC algorithm for M-ary phase shift keying modulated multi-way wireless relay systems. The proposed algorithm can achieve an additional diversity gain by exchanging bit-level or symbol-level soft information between the constitute decoders decoding different information pairs. Moreover, several schemes are proposed for exchange of the soft information between the parallely operating channel decoders. Simulation results demonstrate improved error and convergence performance of the proposed algorithm over the existing algorithms at the expense of non-significant increase in computational complexity.

关键词： fading channels network coding channel coding computational complexity phase shift keying wireless sensor networks diversity reception error statistics decoding relay networks (telecommunication) joint decoder MPSK modulation wireless sensor networks multiway relaying common network configuration uncorrelated fading channels node pair-wise communication physical-layer network coding relay node bit error rate performance improved joint channel decoding-PNC algorithm symbol-level soft information constitute decoders parallely operating channel decoders convergence performance information pairs bit-level soft-information M-ary phase shift keying modulated multiway wireless relay systems

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