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  • 1.
    Chen, Xianhao
    et al.
    Southwest Jiaotong Univ, Chengdu, Sichuan, Peoples R China..
    Liu, Gang
    Southwest Jiaotong Univ, Sch Informat Sci & Technol, SWJTU, Chengdu, Sichuan, Peoples R China.;Southeast Univ, Nanjing, Jiangsu, Peoples R China..
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap. Southwest Jiaotong Univ, Chengdu, Sichuan, Peoples R China.;Southwest Jiaotong Univ, Sch Informat Sci & Technol, Chengdu, Sichuan, Peoples R China..
    Zhang, Xi
    Texas A&M Univ, Networking & Informat Syst Lab, Dept Elect & Comp Engn, College Stn, TX 77843 USA..
    Fan, Pingzhi
    Southwest Jiaotong Univ, Inst Mobile Commun, Chengdu, Sichuan, Peoples R China..
    Chen, Shanzhi
    China Acad Telecommun Technol, Beijing, Peoples R China.;Beijing Univ Posts & Telecommun, Beijing, Peoples R China..
    Yu, F. Richard
    Carleton Univ, Ottawa, ON, Canada..
    WHEN FULL DUPLEX WIRELESS MEETS NON-ORTHOGONAL MULTIPLE ACCESS: OPPORTUNITIES AND CHALLENGES2019Inngår i: IEEE wireless communications, ISSN 1536-1284, E-ISSN 1558-0687, Vol. 26, nr 4, s. 148-155Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    NOMA is a promising radio access technology for 5G wireless systems. The core of NOMA is to support multiple users in the same resource block via power or code domain multiplexing, which provides great enhancement in spectrum efficiency and connectivity. Meanwhile, with the recent advance in self-interference (SI) cancelation techniques, FD wireless communication has become a feasible technology enabling radios to receive and transmit simultaneously. This article aims to investigate the combination of these two emerging technologies. At first, several typical scenarios and protocols are presented to illustrate the application of the FD technique in NOMA systems. Then, a novel NOMA system with FD base stations (BSs) based on C-RAN is proposed. Furthermore, power allocation policies are discussed for the proposed scheme, and simulation results are provided to demonstrate its superiority. Finally, challenges and research opportunities of FD NOMA systems are also identified to stimulate future research.

  • 2.
    Chen, Xianhao
    et al.
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China.;Xidian Univ, State Key Lab Integrated Serv Networks, Xian 710126, Shaanxi, Peoples R China..
    Liu, Gang
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Zhang, Xi
    Texas A&M Univ, Dept Elect & Comp Engn, Networking & Informat Syst Lab, College Stn, TX 77843 USA..
    Xu, Weiqiang
    Zhejiang Sci Tech Univ, Sch Informat Sci & Technol, Hangzhou 310018, Zhejiang, Peoples R China..
    Fan, Pingzhi
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Optimal Power Allocations for Non-Orthogonal Multiple Access Over 5G Full/Half-Duplex Relaying Mobile Wireless Networks2019Inngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 18, nr 1, s. 77-92Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigates the power allocation problems for non-orthogonal multiple access with coordinated direct and relay transmission (CDRT-NOMA), where a base station (BS) communicates with its nearby user directly, while communicating with its far user only through a dedicated relay node (RN). The RN is assumed to operate in either half-duplex relaying (HDR) mode or full-duplex relaying (FDR) mode. Based on instantaneous channel state information (CSI), the dynamic power allocation problems under HDR and FDR schemes are formulated respectively, with the objective of maximizing the minimum user achievable rate. After demonstrating the quasi-concavity of the considered problems, we derive the optimal closed-form power allocation policies under the HDR scheme and the FDR scheme. Then, a hybrid relaying scheme dynamically switching between HDR and FDR schemes is further designed. Moreover, we also study the fixed power allocation problems for the considered CDRT-NOMA systems based on statistical CSI so as to optimize the long-term system performance. The simulations show that our proposed power allocation policies can significantly enhance the performance of CDRT-NOMA systems.

  • 3. Dai, B.
    et al.
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Luo, Y.
    Liu, X.
    Zhuang, Z.
    Xiao, Ming
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Enhancing Physical Layer Security in Internet of Things via Feedback: A General Framework2020Inngår i: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 7, nr 1, s. 99-115, artikkel-id 8856252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, a general framework for enhancing the physical layer security (PLS) in the Internet of Things (IoT) systems via channel feedback is established. To be specific, first, we study the compound wiretap channel (WTC) with feedback, which can be viewed as an ideal model for enhancing the PLS in the downlink transmission of IoT systems via feedback. A novel feedback strategy is proposed and a corresponding lower bound on the secrecy capacity is constructed for this ideal model. Next, we generalize the ideal model (i.e., the compound WTC with feedback) by considering channel states and feedback delay, and this generalized model is called the finite state compound WTC with delayed feedback. The lower bounds on the secrecy capacities of this generalized model with or without delayed channel output feedback are provided, and they are constructed according to variations of the previously proposed feedback scheme for the ideal model. Finally, from a Gaussian fading example, we show that the delayed channel output feedback enhances the achievable secrecy rate of the finite state compound WTC with only delayed state feedback, which implies that feedback helps to enhance the PLS in the downlink transmission of the IoT systems.

  • 4.
    Dai, Bin
    et al.
    Southwest Jiaotong Univ, Sch Informat Sci & Technol, Chengdu 610031, Sichuan, Peoples R China..
    Yu, Liman
    Chengdu Text Coll, Sch Econ & Management, Chengdu 611731, Sichuan, Peoples R China..
    Liu, Xuxun
    South China Univ Technol, Sch Elect & Informat Engn, Guangzhou 510641, Guangdong, Peoples R China..
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap. Southwest Jiaotong Univ, Sch Informat Sci & Technol, Chengdu 610031, Sichuan, Peoples R China..
    Feedback Coding Schemes for the Broadcast Channel With Mutual Secrecy Requirement at the Receivers2019Inngår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 67, nr 9, s. 6039-6052Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The broadcast channel with mutual secrecy requirement at the receivers (BC-MSR-R) is a basic model characterizing the physical layer security (PLS) in the down-link of the wireless communication systems, where one transmitter sends two independent messages to two receivers via a broadcast channel, and each receiver can successfully decode his/her intended message and wishes to overhear the other one's message. This paper studies how to enhance the already existing secrecy rate region of the BC-MSR-R via receivers' feedback. Specifically, we propose two feedback strategies for the BC-MSR-R, where one uses the feedback to generate pure secret keys protecting the transmitted messages, and the other uses the feedback to generate not only keys but also cooperative messages helping the receivers to improve their decoding performance. Different inner bounds on the secrecy capacity region of the BC-MSR-R with noiseless feedback are constructed according to different feedback strategies, and these bounds are further illustrated by a Dueck-type example.

  • 5. Liu, G.
    et al.
    Chen, X.
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap. Southwest Jiaotong University, Chengdu, 610031, China.
    Zhang, X.
    Xiao, Ming
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Fan, P.
    Full-Duplex and C-RAN Based Multi-Cell Non-Orthogonal Multiple Access over 5G Wireless Networks2019Inngår i: ICC 2019 - 2019 IEEE International Conference on Communications (ICC), Institute of Electrical and Electronics Engineers (IEEE), 2019, artikkel-id 8761250Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we propose the full-duplex and cloud radio access network (C-RAN) based multi-cell non-orthogonal multiple access schemes over 5G mobile wireless networks. To cope with the severe intra-cell and inter-cell interferences as well as perform the centralized optimization, we adopt the C-RAN architecture, where the baseband processing and resource management are conducted at a central unit (CU). With the goal of maximizing the weighted sum achievable rate, we formulate the sum rate maximization power allocation problem as a non-convex problem. Thanks to the hidden monotonicity structure of the considered problem, the optimal power allocation algorithm is developed by the monotonic optimization method. Besides, we propose another suboptimal algorithm by employing successive convex approximation method to obtain the close-to-optimal solution with a significantly reduced computational complexity. Extensive simulations are conducted to verify the effectiveness of our proposed power allocation schemes, and confirm the superiority of our proposed C-RAN architecture.

  • 6.
    Liu, Heng
    et al.
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Lu, Jiayi
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Liu, Tianjun
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Hao, Li
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Generalized Interference Alignment for Multi-cell Cooperative Transmission over Doubly Selective Channels2019Inngår i: 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING), IEEE , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper studies the multi-cell cooperation scheme under the time and frequency doubly selective channels, in which the multi-cell co-channel interference are jointly eliminated with the inter-symbol interference to enhance the transmission reception. The basic idea of interference alignment is exploited, with which the link-level interference and network-level interference are aligned to the same dimension before canceled. Instead of assuming the perfect channel information is available at the receivers, an embedded pilot framework is also proposed to track and update the channel state information every short time period, making the proposed scheme more feasible for practical application. Additionally, the pilot design is also discussed and an optimal embedded pilot scheme is derived.

  • 7.
    Pan, Gaofeng
    et al.
    Southwest Univ, Chongqing Key Lab Nonlinear Circuits & Intelligen, Chongqing 400715, Peoples R China. iamantoulakis, Panagiotis D.; Ma, Zheng; Karagiannidis, George K..
    Diamantoulakis, Panagiotis D.
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap. Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece.
    Ding, Zhiguo
    Karagiannidis, George K.
    Simultaneous Lightwave Information and Power Transfer: Policies, chniques and Future Directions2019Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 28250-28257, artikkel-id 8653294Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Harvesting energy from the surrounding environment is an important and practical solution to prolong the life of the energy-constrained Internet-of-Things (IoT) devices, e.g., wireless sensors. Visible light communications (VLC) has been proved able to provide high-speed data links while meeting the illumination requirement. Thereby, the energy of VLC signals may be harvested by the energy-constrained IoT terminals, such as indoor sensors and portable/wearable devices. This paper presents the concept of simultaneous lightwave information and power transfer (SLIPT) with a particular focus on the design of the receiver and the practical methods to realize SLIPT in the domains of time, signal components, and photoelectric converters. Furthermore, this paper also introduces the applications of SLIPT to various network topologies and communication technologies, e.g., multiple input multiple output, hybrid VLC-radio frequency, and secure communications. Finally, a detailed discussion of future research directions and challenges for the design of SLIPT systems is also presented.

  • 8.
    Shen, Zhou
    et al.
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China.;Xidian Univ, State Key Lab Integrated Serv Networks, Xian, Shaanxi, Peoples R China..
    Liu, Gang
    Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China.;Southeast Univ, Natl Mobile Commun Res Lab, Nanjing, Jiangsu, Peoples R China..
    Ding, Zhiguo
    Univ Manchester, Sch Elect & Elect Engn, Manchester, Lancs, England..
    Xiao, Ming
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Yu, F. Richard
    Carleton Univ, Dept Syst & Comp Engn, Ottawa, ON, Canada..
    Optimal Power Allocations for 5G Non-Orthogonal Multiple Access with Half/Full Duplex Relaying2019Inngår i: ICC 2019 - 2019 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recently, power allocation has attracted more and more attention in order to optimize the performance of nonorthogonal multiple access (NOMA) systems. Different from existing works, the power allocation problems are investigated for cooperative NOMA systems with dedicated amplify-and-forward half-duplex relay (NOMA-HDR) and full-duplex relay (NOMA-FDR). From the fairness standpoint, the power allocation problems are formulated to maximize the minimum achievable user rate in the considered systems. The problems for both NOMA-HDR and NOMA-FDR systems with two-user and M-user are addressed. The closed-form power allocation policy of two-user NOMA-HDR system is obtained. Also, the optimal numerical power allocation policies for two-user NOMA-FDR and M-user NOMA-HDR systems are obtained. In addition, the problem for M-user NOMA-FDR systems is solved in noise-limited environment. Simulation results show that the proposed NOMA-HDR or NOMA-FDR scheme with power adaption clearly outperforms the NOMA-HDR or NOMA-FDR scheme with fixed power allocation. Besides, when the residual self-interference channel gain is small, the performance of NOMA-FDR system is better than the NOMA-HDR system.

  • 9.
    Zhai, Kai
    et al.
    Southwest Jiaotong Univ, Prov Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Ma, Zheng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Lei, Xianfu
    Southwest Jiaotong Univ, Prov Key Lab Informat Coding & Transmiss, Chengdu 610031, Sichuan, Peoples R China..
    Closed-formed distribution for the SINR of MMSE-detected MIMO systems and performance analysis2018Inngår i: AEU - International Journal of Electronics and Communications, ISSN 1434-8411, E-ISSN 1618-0399, Vol. 97, s. 16-24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we investigate the error performance of multiple-input multiple-output (MIMO) wireless communications systems using minimum mean-square error (MMSE) detection. Particularly, a new closed-form statistical distribution for the output signal-to-interference-plus-noise ratio (SINR) of MMSE receiver is derived, for independent Rayleigh fading channels. The expression for the distribution of SINR is shown to be a linear combination of gamma distributions and polynomial of where xis the SINR. Base on the derived distribution for the SINR, closed-form and approximated expressions for the symbol error probability (SEP) of quadrature amplitude modulation (QAM) and phase shift keying (PSK) signaling are obtained, respectively. The derived SINR density and SEP are valid for arbitrary number of transmit and receive antennas. Furthermore, a reduced complexity approximation is introduced to obtain the SINR distribution and SEP performance of MMSE-Detected MIMO Systems with a large number of antennas. The provided simulation results confirm the validity of our theoretical analysis for both the SINR and SEP. All rights reserved.

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