People

Students

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XIN Haiyang
shakeel
Shakeel SALAMAT
Mehrdad
Mehrdad TAHERNIA
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DING Tian
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PAN Haoyuan
Saleh
Saleh NIKOOROO
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WANG Zhaorui

Research Staff

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Dr. WANG Taotao
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Dr. HE Jianghao
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CHEN Jian
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ZHANG Minglong
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SHAO Yulin

Research

Physical-Layer Network Coding (PNC)

Our group first put forth the concept of physical-layer network coding (PNC) in a Mobicom 2006 paper. Since then, PNC has developed into a subfield of wireless communications and networking with a wide following. Many papers—by our group as well as other groups—have been published on the topic. In addition, numerous conference/workshop sessions and special journal issues have been dedicated to it.

The key idea of PNC is to exploit the network coding operation that occurs naturally when electromagnetic (EM) waves are superimposed on one another. In contrast to conventional network coding which performs network-coding arithmetic on digital bit streams after reception, PNC makes use of the additive nature of superimposed EM waves for equivalent network coding operation. PNC has the potential to improve network throughput substantially. For example, in a two-way relay channel in which two end nodes communicate via a relay node (e.g., two ground stations communicating via a satellite), application of PNC can boost capacity by 100%.

Our group conducts both theoretical and experimental investigations on PNC. There is a healthy symbiosis between our theoretical and experimental research, with one generating interesting problems for further investigation by the other.

Milestones

  • 2006

    Germination of the concept of PNC

    [1] S. Zhang, S. C. Liew, P. P. Lam, “Physical-Layer Network Coding,” ACM Mobicom 2006, Sept 2006.

  • 2008

    First framework for channel-coded PNC

    [2] S. Zhang, S. C. Liew, “Channel Coding and Decoding in a Relay System Operated with Physical-Layer Network Coding,” IEEE J. on Selected Areas in Commun., vol. 27, no. 5, pp. 788-796, June 2009.

  • 2010

    Frequency-domain PNC implementation project begins

  • 2011

    First demonstration that asynchrony is not a game killer for PNC

    [8] L. Lu, S. C. Liew, “Asynchronous Physical-layer Network Coding,” IEEE Trans. on Wireless Communications, vol. 11, no. 2, pp. 819-831, Feb. 2012.

    [9] L. Lu, S. C. Liew, S. Zhang, “Optimal Decoding Algorithm for Asynchronous Physical-Layer Network Coding,” IEEE ICC, June 2011.

    First PNC prototype

    [10] L. Lu, T. Wang, S. C. Liew, S. Zhang, “Implementation of Physical-layer Network Coding,” Elsevier Phycom, Special Issue of Physical Communication on “Network Coding and Its Applications to Wireless Communications”, vol. 6, pp. 74-87, Mar. 2013.

    [11] L. Lu, T. Wang, S. C. Liew, S. Zhang, “Implementation of Physical-layer Network Coding,” IEEE ICC 2012, June 2012.

  • 2012

    First application of PNC in optical networks

    [12] Z. Liu, M. Li, L. Lu, C. K. Chan, S. C. Liew, L. K. Chen, “Optical Physical-layer Network Coding,” IEEE Photon. Technol. Lett., vol. 24, no. 8, pp. 1424-1427, Aug. 2012.

    [13] Q. Wang, K. H. Tse, L. K. Chen, S. C. Liew, “Physical-layer Network Coding for VPN in TDM-PON,” IEEE Photon. Technol. Lett., vol. 24, no. 23, pp. 2166-2168, Dec. 2012.

    Survey/tutorial on overall research landscape of PNC

    [14] S. C. Liew, S. Zhang, L. Lu, “Physical-layer Network Coding: Tutorial, Survey, and Beyond,” Invited Paper, Elsevier Phycom, Special Issue of Physical Communication on “Network Coding and Its Applications to Wireless Communications”, vol. 6, pp. 4-42, Mar. 2013.

  • 2013

    Joint channel estimation and channel decoding in PNC

    [15] T. Wang, S. C. Liew, “An EM Approach for Joint Channel Estimation and Channel Decoding in Systems Employing Physical-Layer Network Coding,” IEEE ICASSP 2013, May 2013.

    First real-time PNC prototype with exchange of image files between two users via a PNC relay

    [16] L. Lu, L. You, Q. Yang, T. Wang, M. Zhang, S. Zhang, S. Liew, “Real-Time Implementation of Physical-layer Network Coding,” SRIF 2013 (an ACM Sigcomm Workshop), Aug. 2013.

    First put forth the concept of PNC atoms

    [17] J. He, S. C. Liew, “Building Blocks of Physical-layer Network Coding,” IEEE SECON 2013, June 2013.

    First Application of PNC in Fiber-Wireless

    [26] Z. Liu, L. Lu, L. You, C. K. Chan, and S. C. Liew, “Optical Physical-layer Network Coding over Fiber-Wireless,” in Proc. ECOC, 2013.

    First use of PNC for broadcasting

    [18] S. Feng, S. C. Liew, “Wireless Broadcast with Physical-Layer Network Coding,” IEEE Globecom 2013, Dec. 2013.

    FMIMO PNC and PNC for multi-way relay networks

    [3] S. Zhang, S. C. Liew, “Physical Layer Network Coding with Multiple Antennas,” IEEE WCNC 2010, Apr 2010.

    [4] F. Wang, S. C. Liew, D. Guo, “Wireless MIMO Switching with Zero-forcing Relaying,” Allerton 2011, Sep. 2011.

    [5] F. Wang, S. C. Liew, D. Guo, “Wireless MIMO Switching with Zero Forcing and Network Coding,” IEEE J. on Selected Areas in Commun., vol. 30, no. 8, pp. 1452-1463, Sep. 2012.

    [6] F. Wang, X. Yuan, S. C. Liew, D. Guo, “Wireless MIMO Switching: Weighted Sum Mean Square Error and Sum Rate Optimization,” IEEE Trans. on Info. Theory, vol. 59, no. 9, pp. 5297-5312, Sep. 2013.

    [7] F. Wang, X. Yuan, S. C. Liew, Y. Li, “Bidirectional Cellular Relay Network with Distributed Relaying,” IEEE J. on Selected Areas in Commun., vol. 31, no. 10, pp. 2082-2098, Oct. 2013.

    [20] H. Xin, X. Yuan, S. C. Liew, “Space-Division Approach for Multi-pair MIMO Two Way Relaying: A Principal-Angle Perspective,” IEEE Globecom 2013, Dec. 2013.

  • 2014

    First Comprehensive Analysis of PNC with Higher-order Modulations (e.g., PAM)

    [24] L. Shi, S. C. Liew, and L. Lu, “On the Subtleties of q-PAM Linear Physical-layer Network Coding,” arXiv:1411.1161, 2014.

    First Application of PNC in Vehicular Network

    [26] I. W.-H. Ho, S. C. Liew, and L. Lu, “Feasibility Study of Physical-Layer Network Coding in 802.11p VANETs,” in Proc. IEEE ISIT, 2014.

  • 2015

    First Optimal Multipath PNC Framework

    [25] M. Zhang, L. Lu, and S. C. Liew, “An Optimal Decoding Strategy for Physical-layer Network Coding over Multipath Fading Channels,” to appear in IEEE Trans. Veh. Technol., 2015.

    First Convolutional-Coded Asynchronous PNC

    [27] Q. Yang and S. C. Liew, “Asynchronous Convolutional-Coded Physical-Layer Network Coding,” IEEE Trans. Wireless Commun., 2015.

    PNC Monograph

    [28] S. C. Liew, L. Lu, and S. Zhang, “A Primer on Physical-Layer Network Coding, Synthesis Lectures on Communication Networks (Series Editor J. Walrand)” Morgan & Claypool, 2015.

  • future

    Second generation of PNC prototype supporting high bandwidth and high data rate

Network Coding Multiple Access (NCMA)

In an offshoot investigation from “conventional PNC”, we are now beginning to explore the role of PNC decoding in multiple access networks.

Prior studies of PNC focused on its use in relay networks. This is not surprising given that network coding is grounded on the idea of intermediate nodes (i.e., relays) mixing and forwarding information from several sources. Our recent experiments, however, point to a new frontier for PNC. Specifically, we found that PNC could also play a role in non-relay networks.

NCMA, another means of making use of interference, combines PNC together with conventional multiuser decoding (MUD) to boost system throughput, by allowing multiple users to transmit simultaneously to the same AP. A demo about NCMA prototype with two end users can be found in (https://youtu.be/DgMeck1B9O8).

Milestones

  • 2012

    First demonstration the PNC decoding can play a role In multiple-access networks

    [19] L. Lu, L. You, S. C. Liew, “Network-Coded Multiple Access,” IEEE Trans. on Mobile Computing, 2014.

  • 2014

    Real-time NCMA prototype and theoretical analysis of NCMA

    [21] L. You, S. C. Liew, L. Lu, “Network-Coded Multiple Access II: Toward Real-Time Operation with Improved Performance,” IEEE J. on Selected Areas in Commun., Dec. 2014.

    [23] S. Yang, S. C. Liew, L. You, Y. Chen, “Linearly-Coupled Fountain Codes for Network-Coded Multiple Access,” IEEE ITW, Nov. 2014.

  • 2015

    Theoretical Analysis for NCMA

    [29] S. Yang, Y. Chen, S. C. Liew, and L. You, “Coding for Network-Coded Slotted ALOHA,” arXiv:1502.03903, 2015.

    First Higher-order Modulated NCMA System (Beyond BPSK)

    [30] H. Pan, L. Lu, and S. C. Liew, “Network-Coded Multiple Access with Higher-order Modulations,” arXiv:1504.03426, 2015.

Other Research Topics


Contact

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Phone: (+852) 3943-8382