PhD position in wireless Communications at CITI Lab

Leave a comment
logo-citi
Title

Combination of Spatial Modulation and Full-Duplex for future Wireless transceivers

Laboratory

CITI Lab. Centre of Innovation in Telecommunications and Integration of Service (www.citilab.fr)

Contact

Guillaume Villemaud

guillaume.villemaud@insa-lyon.fr

Context and background

Usually in wireless communications, the wireless medium is a shared and limited resource. Current wireless standards always share the medium with Half-Duplex principle: the transmission and reception of signals are done in two separate time slots or two different frequency bands. Besides, the transceiver can only transmit and receive one signal at the same time at the same frequency.

More recent research works [1-3] are focusing on an alternate approach: instead of sharing the medium with Half-Duplex principle, the entire licensed frequency band is shared for simultaneous transmission and reception, what is called Full-Duplex. The major drawback of this kind of Full-Duplex system is therefore that a very high level of interference is created by the transceiver itself while trying to receive a distant signal (known as the self-interference). Besides, the concept of MIMO communications is widely used, but supposes a large increase in the complexity, cost and energy consumption of multi-antenna transceivers. Using Spatial Modulation is a very promising way of developing simpler MIMO transceivers [18], and could be particularly relevant in combination with Full-Duplex.

Our laboratory has already a strong and recognized background on Full-Duplex communications [4-9]. A first thesis was dedicated to this subject, paving the way for more realistic developments and applications. Besides, another thesis has started last year, to study the theoretical bounds of physical layer secrecy by using FD.

Therefore, we have already proposed an architecture enabling FD communications. To approach this goal, we use an active analog radio frequency self-interference cancellation (AARFSIC) method or a combination scheme of the AARFSIC and active digital self-interference cancellation in time domain (ADSICT) to cancel the strong self-interference (SI) induced by the Full-Duplex principle. Based on the Full-Duplex radio, we proposed a flexible Full-Duplex Dual-Band (FDDB) OFDM radio transceiver by combining the Dual-Band RF front-end with Full-Duplex.

These proposed architectures have been studied in theory and in simulations, thus one goal of this thesis will be to develop some practical experimentations of Full-Duplex communications, based on Vector Signal Generators and Vector Signal Analyzers, in connection with simulated parts for digital processing purpose. Furthermore, some experiments in the Cortexlab facility is also an objective of this work (www.cortexlab.fr).

Keywords

Wireless communications, RF architecture, digital processing, full-duplex, MIMO, Spatial modulation.

Main objectives

In the past years, considerable efforts have been devoted to prove the potential of using in-band full-duplex for future wireless communications, both from the hardware side and the networking side. The major difficulty of IBFD being the large amount of self-interference (SI), this interference is mitigated at three levels in the transceiver: antenna cancellation, analog cancellation, and digital cancellation. However, most of the proposed structures are inherently limited to fixed narrowband operations and almost no system-level demonstrations exist that prove the value of IBFD beyond a straightforward bi-directional link. Moreover, most of existing studies are based on theoretical analyses, simulations, or simple experimental testbeds.

Therefore, the goal of this thesis is threefold:

–      To propose and develop some wideband and/or flexible radio architectures dedicated to full-duplex communications, using Spatial Modulation, from the antenna to the digital compensation implementation;

–      To develop a complete study and optimization of this kind of architecture, starting from theoretical performance, going to simulation frameworks, and developing a proof of concept;

–      To establish some reference scenarios to be tested with this proof of concept, for specific applications in practice beyond the usual toy-example of a straightforward bi-directional. In particular, we plan to explore and demonstrate applications such as secure communications through self-jamming, or the use of primary-user detection in Cognitive Radios.

Bottlenecks

As stated above, the main problem of Full-Duplex is to mitigate the strong Self-Interference created in the structure. Using Spatial Modulation enable to switch between several antennas to emit the signal of interest. Then, the challenge will be to receive a distant signal on unused antennas during this emission time, cancelling the Self-Interference and reconstructing the distant signal while switching at a high rate between the antennas.

Expected contributions

To the best of our knowledge, it exists no actual combination of Spatial modulation and Full-Duplex. Only some theoretical bounds of potential performance of such a combination was proposed in [17] but without taking into account any realistic RF architecture. Thus an actual and functional architecture combining Full-Duplex and Spatial Modulation would be a great breakthrough.

Scientific program and schedule

The overall schedule of the thesis is quite simple. The first six months will be dedicated to an exhaustive state-of-the-art not only on Full-Duplex systems and Spatial Modulation, but also on all progress on wideband and flexible radio systems and on interference cancellation algorithms. The remaining of the first year will focus on building the framework of theoretical studies and the associated simulation tools.

The second year will be devoted to extensive theoretical and simulation investigations, as long as choice of the required equipment for experimentations. By the end of this second year, everything should be fixed in order to be able to begin experimentations in the third year.

The third and final year of the thesis will see the production of scientific results via publications of the most significant works, extensive experimentations with feedback on theoretical and simulation studies and global drawing of the potentialities of exploitation of the proposed techniques. A large dissemination to the community is planned in order to encourage the use of these approaches in future communication networks. Finally the thesis manuscript will be written and the thesis will be defended.

Apart from the material part, the proposed tools are the Matlab and the Keysight’s ADS software. The thesis will take place within the Inria Socrate team of the CITI laboratory (http://www.citi-lab.fr/).

Supervisors

Guillaume Villemaud (HDR, 50%), Florin Hutu (50%)

Dissemination

Of course, a large dissemination of the proposed works will be ensured in international conferences, high quality journals and potentially via patents. Our goal is also to collaborate in COST actions, particularly we are strongly involved in the new IRACON action (merge of the NEWCOM# and COST IC1004) and therefore this will offer a good place of interaction with other European partners. We also expect that this project will be a first step to build a larger consortium for future H2020 calls and to participate in the definition of new standards, particularly to encourage the integration of Full-Duplex in the 5G networks.

Moreover, this work could be naturally applied to IoT scenarios, therefore the context of the SPIE IoT Chair hosted at the CITI laboratory could be a rich place of interaction and collaboration.

Expected profile of the candidate

Master of Sciences or Engineering degree in Telecommunications or Electrical Engineering with a strong background in radiocommunications, RF architectures and signal processing.

References

[1]       A. Sabharwal, P. Schniter, D. Guo, D.W. Bliss, S. Rangarajan, R. Wichman, ‘In-band Full-duplex Wireless: Challenges and Opportunities’, IEEE Journal on Selected Areas in Communications (JSAC), 2014.

[2]        B. Debaillie, D. J. van den Broek, C. Lavin, B. van Liempd, E. A. M. Klumperink, C. Palacios, J. Craninckx, B. Nauta, and A. Parssinen, “Analog/RF solutions enabling compact full-duplex radios,” IEEE Journal on Selected Areas in Communications (JSAC), 2014.

[3]        H. Alves, C. Lima, P. Nardelli, R. Demo Souza, M. Latva-aho: “On the Average Spectral Efficiency of Interference-Limited Full-Duplex Networks”, CrownCom 2014, Oulu, Finland, June 2014.

[4]        Z. Zhan and G. Villemaud, “Combination of Digital Self-Interference Cancellation and AARFSIC for Full-Duplex OFDM Wireless,” IEEE/CIC International Conference on Communications in China (ICCC), Shanghai, China, 13-15 Oct. 2014.

[5]        Z. Zhan, G. Villemaud, F. Hutu and J-M. Gorce, “Digital Estimation and compensation of I/Q imbalance in Full-Duplex Dual-Band OFDM Radio,” The 25th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Washington, DC, USA, 2-5 Sep. 2014.

[6]        Z. Zhan, G. Villemaud, F. Hutu and J-M. Gorce, “Digital I/Q Imbalance Correction for Full-Duplex Dual-Band OFDM Radio Transceivers”, International Journal of Microwave and Wireless Technologies, 2015.

[7]        Z. Zhan, G. Villemaud, J-M. Gorce, “Analysis and Reduction of the Impact of Thermal Noise on the Full-Duplex OFDM Radio”, IEEE Radio and Wireless Symposium (RWS) 2014, Newport Beach, Jan. 2014.

[8]        Z. Zhan, G. Villemaud, J-M. Gorce, “Design and Evaluation of a Wideband Full-Duplex OFDM System Based on AASIC”, IEEE Personal, Indoor and Mobile Radio Communications Symposium,  PIMRC2013, London, September 2013.

[9]        Z. Wei, G. Villemaud, T. Risset, “Full Duplex Prototype of OFDM on GNURadio and USRPs”, IEEE Radio and Wireless Symposium (RWS) 2014, Newport Beach, Jan. 2014.

[10]      Balatsoukas-Stimming, Alexios, et al. “On self-interference suppression methods for low-complexity full-duplex MIMO.” Signals, Systems and Computers, 2013 Asilomar Conference on. IEEE, 2013.

[11]      Belanovic, Pavle, Alexios Balatsoukas-Stimming, and Andreas Burg. “A multipurpose testbed for full-duplex wireless communications.” Electronics, Circuits, and Systems (ICECS), 2013 IEEE 20th International Conference on. IEEE, 2013.

[12]      Alexandris, K.; Balatsoukas-Stimming, A.; Burg, A., “Measurement-based characterization of residual self-interference on a full-duplex MIMO testbed,” Sensor Array and Multichannel Signal Processing Workshop (SAM), 2014 IEEE 8th , vol., no., pp.329,332, 22-25 June 2014.

[13]      G. Villemaud, “Study of a Full-Duplex Dual-Band OFDM Transceiver”, DUPLO workshop, Crowncom 2014, Oulu, June 2014.

[14]      Shanzhi Chen; Jian Zhao, “The requirements, challenges, and technologies for 5G of terrestrial mobile telecommunication,” Communications Magazine, IEEE , vol.52, no.5, pp.36,43, May 2014.

[15]      Hossain, E., & Hasan, M. (2015). “5G Cellular: Key Enabling Technologies and Research Challenges”. arXiv preprint arXiv:1503.00674.

[16]      G.  Zheng,  I.  Krikidis,  J.  Li,  A.  P.  Petropulu,  and  B.  Ottersten,  “Improving  physical  layer  secrecy  using  full-duplex  jamming  receivers,” IEEE Trans. Signal Process., vol. 61, no. 20, pp. 4962–4974,  2013.

[17]     B. Jiao, M. Wen, M. Ma and H. V. Poor, “Spatial Modulated Full Duplex,” in IEEE Wireless Communications Letters, vol. 3, no. 6, pp. 641-644, Dec. 2014.

[18]      M. Di Renzo and H. Haas, “Performance analysis of Spatial Modulation,” 2010 5th International ICST Conference on Communications and Networking in China, Beijing, 2010

 

 


PhD Defense: “High-performance Coarse Operators for FPGA-based Computing”, by Matei Istoan, on 6th April

Leave a comment
matei

The defense will take place on Thursday 6th April at 14:00 in the Chappe Amphitheater, Claude Chappe building, INSA Lyon.
The presentation will be held in English with slides in English.

Jury

Reviewers

Paolo IENNE, EPFL Lausanne
Roselyne CHOTIN-AVOT, UPMC Paris

Examiners

David THOMAS, Imperial College London
Frédéric PETROT, ENSIMAG, Saint Martin d’Hères
Olivier SENTIEYS, ENSSAT, Lannion

Advisors

Florent DE DINECHIN, INSA Lyon

Abstract

Field-Programmable Gate Arrays (FPGAs) have been shown to sometimes outperform mainstream microprocessors.
The circuit paradigm enables efficient application-specific parallel computations.
FPGAs also enable arithmetic efficiency: a bit is only computed if it is useful to the final result.
To achieve this, FPGA arithmetic shouldn’t be limited to basic arithmetic operations offered by microprocessors.This thesis studies the implementation of coarser operations on FPGAs, in three main directions.New FPGA-specific approaches for evaluating the sine, cosine and the arctangent have been developed.
Each function is tuned for its context and is as versatile and flexible as possible.
Arithmetic efficiency requires error analysis and parameter tuning, and a fine understanding of the algorithms used.

Digital filters are an important family of coarse operators resembling elementary functions: they can be specified at a high level as a transfer function with constraints on the signal/noise ratio, and then be implemented as an arithmetic datapath based on additions and multiplications.
The main result is a method which transforms a high-level specification into a filter in an automated way.
The first step is building an efficient method for computing sums of products by constants.
Based on this, FIR and IIR filter generators are constructed.

For arithmetic operators to achieve maximum performance, context-specific pipelining is required.
Even if the designer’s knowledge is of great help when building and pipelining an arithmetic datapath, this remains complex and error-prone.
A user-directed, automated method for pipelining has been developed.

This thesis provides a generator of high-quality, ready-made operators for coarse computing cores, which brings FPGA-based computing a step closer to mainstream adoption.
The cores are part of an open-ended generator, where functions are described as high-level objects such as mathematical expressions.


CITI Talk: “Two Channels with Almost No Benefit from CSI”, by Ligong Wang, on 27th March

Leave a comment
wlg10

The next CITI talk will take place on 27th March at 3 pm in room TD-C.

This talk entitled “Two Channels with Almost No Benefit from CSI” will be presented by Ligong Wang.

Abstract

For many communication channels, causal or noncausal channel-state information (CSI) at the transmitter can help to significantly increase their communication capacity. In this talk we discuss two channels for which this is not the case. The first is the very noisy channel. We show that noncausal CSI at the transmitter provides little additional capacity improvement over causal CSI. The second channel is the Poisson channel with random, time-varying dark current. On this channel, capacity improvement from both causal and noncausal CSI is shown to be negligible.

Speaker biography

Ligong Wang received the B.E. degree in electronic engineering from Tsinghua University, Beijing, China, in 2004 and the M.Sc. and Ph.D. degrees in electrical engineering from ETH Zurich, Switzerland, in 2006 and 2011 respectively. In the years 2011-2014, he was a Postdoctoral Associate at the Department of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology, Cambridge, MA, USA . He is now a researcher (chargé de recherche) with CNRS, France, and is affiliated with ETIS laboratory in Cergy-Pontoise. His research interests include classical and quantum information theory, and digital, in particular optical communications.


CITI Talk: “Broadcasting with delayed CSIT: finite SNR analysis and heterogeneous feedback”, by Chao HE, on 15th March

Leave a comment
384_htmlarea_perso_9520_0

The next CITI talk will take place on 15th March at 11 am in Amphi Chappe.

This talk entitled “Broadcasting with delayed CSIT: finite SNR analysis and heterogeneous feedback” will be presented by Chao HE.

Abstract

One of the key techniques for future wireless networks, namely state-feedback enabled interference mitigation, is explored with information theoretical tools under some realistic settings. In order to verify the usefulness of delayed CSIT in harsh situations, we investigate it with finite SNR and/or feedback heterogeneity in a broadcast communication setup. In the first part of this talk, we are mainly interested in showing the finite SNR performance of delayed CSIT and the similarity between the results in Gaussian and erasure channels. Several relatively simple schemes are proposed in multi-user broadcast channels when states are assumed to be fully known at the destinations but only strictly causally at the transmitter. Enhancement in terms of higher symmetric rates and more input alphabet options are then characterized when analyzing the corresponding regions in Gaussian/erasure cases. In the second part of this talk, algorithms adapted to heterogeneous feedback are targeted as only part of communication nodes are involved in the feedback process. In particular, we concentrate on 1) broadcast channel with feedback from partial receivers, 2) broadcast relay channel with feedback at the relay. Improvements on achievable rates are justified in either cases via analysis and some examples.

Speaker biography

Chao He received his B.E. degree in Electrical Engineering from Southeast University in 2012, and the M.Sc. degree in SAR from Supélec in 2013. He obtained the Ph.D. degree from CentraleSupélec of Université Paris Saclay in 2016. His current research interests lie in the areas of multi-user information theory and limited feedback.


PhD Defense: “How to operate IoT networks with contracts of quality of service (Service Level Agreements)”, by Guillaume Gaillard, on 19th December

Leave a comment
g-gaillard

The defense will take place on Monday 19th December at 10:00 in the Chappe Amphitheater, Claude Chappe building, INSA Lyon.
The presentation will be held in French with slides in English.

Jury

Reviewers

Thierry TURLETTI, Inria- Sophia Antipolis
Pascale MINET, Inria- Paris

Examiners

Pascal THUBERT, Cisco Systems
Philippe OWEZARSKI, CNRS- Toulouse
Isabelle GUÉRIN-LASSOUS, Lyon 1 University

Advisors

Dominique BARTHEL, Orange Labs- Meylan
Fabrice VALOIS, INSA Lyon
Fabrice Theoleyre, CNRS- ICube

This thesis work has been done in collaboration between Orange Labs, INSA Lyon, ICube, and Inria UrbaNet in the CITI Lab.

Abstract

With the growing use of distributed wireless technologies for modern services, the deployments of dedicated radio infrastructures do not enable to ensure large-scale, low-cost and reliable communications. This PhD research work aims at enabling an operator to deploy a radio network infrastructure for several client applications, hence forming the Internet of Things (IoT).
We evaluate the benefits earned by sharing an architecture among different traffic flows, in order to reduce the costs of deployment, obtaining a wide coverage through efficient use of the capacity on the network nodes. We thus need to ensure a differentiated Quality of Service (QoS) for the flows of each application.
We propose to specify QoS contracts, namely Service Level Agreements (SLAs), in the context of the IoT. SLAs include specific Key Performance Indicators (KPIs), such as the transit time and the delivery ratio, concerning connected devices that are geographically distributed in the environment. The operator agrees with each client on the sources and amount of traffic for which the performance is guaranteed. Secondly, we describe the features needed to implement SLAs on the operated network, and we organize them into an SLA management architecture.
We consider the admission of new flows, the analysis of current performance and the configuration of the operator’s relays.
Based on a robust, multi-hop technology, IEEE Std 802.15.4-2015 on TSCH mode, we provide two essential elements to implement the SLAs: a mechanism for the monitoring of the KPIs, and KAUSA, a resource allocation algorithm with multi-flow QoS constraints. The former uses existing data frames as a transport medium to reduce the overhead in terms of communication resources. We compare different piggybacking strategies to find a tradeoff between the performance and the efficiency of the monitoring. With the latter, KAUSA, we dedicate adjusted time-frequency resources for each message, hop by hop. KAUSA takes into account the interference, the reliability of radio links and the expected load to improve the distribution of allocated resources and prolong the network lifetime. We show the gains and the validity of our contributions with a simulation based on realistic traffic scenarios and requirements.
Keywords: Quality of Service, Wireless Sensor Networks, Multi-hop, Internet of Things, Service Level Agreement, Key Performance Indicators, Reliability, Network Management, Network Monitoring, Scheduling, 6TiSCH

 


HDR Defense: “Complexity of Ambient Software: from Composition to Distributed, Contextual, Autonomous, Large-scale Execution”, by Frédéric Le Mouël, on 28th November

Leave a comment
flm

The defense will take place on Monday 28th November at 10:00 in the Chappe amphitheatre, Chappe Building, INSA Lyon.

Jury

Reviewers

Pr Thierry DELOT, Valenciennes University
Pr Daniel HAGIMONT, ENSEEIHT
Pr Michel RIVEILL, Nice Sophia Antipolis University

Examiners

Pr Isabelle GUÉRIN LASSOUS, Claude Bernard Lyon 1 University
Pr Fabrice VALOIS, INSA de Lyon
MCF Philippe ROOSE, Pau et Pays de l’Adour University

Abstract

Combined with the development of middleware in the 1990-2000, the Ambient Intelligence has shaped the 2020 scenarios. With a growing number of devices, smartphones, sensors, connected watches, glasses, etc., these scenarios however suffer. With increasing constraints of energy consumption, size and mobility, the deployment, management and programming of these environments have become greatly complex. Middleware present good properties of abstraction – allowing modularity and an efficient reuse – and interconnection – allowing openness and safety of systems. Hence, they play a paramount role in the current deployment of the Internet of Things.

During last years, my contributions have focused on studying, finding solutions to three middleware issues in this context: dynamism, scalability and autonomy. Several platforms have been developed to validate the scientific and technologic choices performed. Jooflux and ConGolo are JVM-based approaches integrating dynamism in-application, either explicitly with ConGolo contextual programming, or implicitly with transparent aspect weaving of Jooflux. AxSeL, ACOMMA and MySIM are service-oriented approaches capturing the dynamism with dynamic and contextual service loading/unloading, collaborative execution, and semantic QoS-based service composition. CANDS allows to manipulate and manage very important information flow on very large service graphs while preserving millisecond-response time. Pri-REIN improves it with quality of service.

An important result has been to show that the autonomy property is strongly correlated with the middleware application domains, and was particularly tested in smart cities with guidance application, in-street parking management and traffic optimisation.

These works have strongly been supported by five defended thesis.

For future works, I will consider specific IoT issues to reduce the human intervention: large-scale initial deployment, safe and secure management, and distributed au autonomous decision-making inferring locally a global behaviour – i.e. Small Data.

 


Best Paper Award for Dynamid!

Leave a comment
best-paper-award

Dynamid Team members Roya Golchay, Frédéric Le Mouël, Julien Ponge and Nicolas Stouls won the Best Paper Award at CollaborateCom 2016!

The 12th EAI International Conference on Collaborative Computing: Networking, Applications and Worksharing took place on 12th and 13th November 2016 in Beijing, China.

Read the article “Spontaneous Proximity Cloud: Making Mobile Devices to Collaborate for Resource and Data Sharing” here

dsc_0128


CITI Talk: “​​Challenges of a Reflective Platform”, by Stéphane Ducasse, on 24th November

Leave a comment
s-ducasse

The next CITI talk will take place on 24th November at 11 am in Amphi Chappe.

This talk entitled “Challenges of a Reflective Platform” will be presented by Stéphane Ducasse directeur de recherche at Inria-Lille..

Abstract

Pharo is a live programming reflective dynamic language and environment. His tools are delivering an excellent programmer experience and are heavy user of its reflective abilities.
In this talk we will present briefly Pharo an immersive reflective platform and programming language (www.pharo.org) and focused on:
(1) the problems we encounter daily (how to update core libraries while they are used to execute the updater itself, how can we get VM execution benefit from hot state right at system startup and without warming up, how can we isolate reflective parts of the system, what are the code representations we need to make happy the VMs and IDE)
(2) the infrastructure that we would like to have: since we are able to bootstrap the core of the system under 80 k, we can start thinking about multiple versions of the system coexisting, the question of the memory model is then important. Another question is how can we build a system where users can decide when they want to move code from one version to the other ones. Similarly, we would like to resume work on PharoNoOS and work on Xen hypervisor to gain benefit of hot hotspot and fast boot time.

Speaker biography

Stéphane is directeur de recherche at Inria. He has more than 20 years of experience in software maintenance. He leads the RMoD (rmod.lille.inria.fr) team. He is expert in two domains: object-oriented language design and reengineering.  He worked on traits, composable groups of methods. Traits have been introduced in  Pharo, Perl, PHP and  under a variant into Scala, Fortress of SUN Microsystems.  He is also expert on software quality, program understanding, program visualizations, reengineering and metamodeling. He is one of the developer of Moose, an open-source software analysis platform www.moosetechnology.org.  He created www.synectique.eu a company building dedicated tools for advanced software analysis. He is one of the visionary core developers behind Pharo www.pharo.org a new exciting reflective and immersive dynamically-typed language. According to google, his h-index is 49 for about 10 K citations. He is writing some new books around Pharo and having fun building a great and exciting system.


CITI Talk: “​​Who will drive cars ? Public Vehicles for Future Urban Transportation”, by Min-You Wu, on 8th November

Leave a comment
min-you-wu

The next CITI talk will take place on 8th November at 10.30 am in Amphi Chappe.

This talk entitled “Who will drive cars ? Public Vehicles for Future Urban Transportation” will be presented by Min-You Wu, from Shangai Jiao-Tong, China.

Abstract

Urban transportation is undergoing a dramatic change. Conventional transportation consisting of private vehicles, taxis and buses will be substituted by trip service with autonomous vehicles. Transition from owning private vehicles to purchasing trip service is one of the most revolutionary changes in this century.
In this talk we discuss issues of autonomous trip services. We will discuss cost reduction of trip services. Three most important factors for low-cost trip services are manpower, energy and ridesharing. We focus on the ridesharing problem. We will discuss various techniques to increasing the sharing factor including passenger transfer, incentive mechanism and advanced booking.
We propose a new paradigm of transportation system for future smart cities, namely, Public Vehicles (PVs). With PVs, the number of vehicles as well as the required parking space will be significantly reduced. There will be less traffic congestion, less energy consumption and less pollution. The key issue of implementing an effective PV system is to design efficient planning and scheduling algorithms. We compare the PV system with conventional systems.

Speaker biography

Min-You Wu is a Professor in the Department of Computer Science and Engineering at Shanghai Jiao Tong University. He serves as the Chief Scientist at Grid Center of Shanghai Jiao Tong University. He is a research professor of the University of New Mexico, USA. His research interests include wireless and sensor networks, vehicular networks, multimedia networking, parallel and distributed systems, and compilers for parallel computers. He has published over 200 journal and conference papers in the above areas. His research has been supported by National Science Foundation, DoD, DoE, DARPA, China 863 program, China 973 program, Ministry of Education of China and Natural Science Foundation of China. He is a Vice Chair of Technical Committee of Computer Architecture, CCF. He is a senior member of IEEE and CCF.