Collaborative & Cognitive Networking and Open Spectrum

Speaker:	Dr. Qian ZHANG
		Department of Computer Science
		Hong Kong University of Science & Technology

Title:		"Collaborative & Cognitive Networking and Open Spectrum"

Date:		Monday, 5 December 2005

Time:		4:00pm - 5:00pm

Venue:		Lecture Theatre F
		(Leung Yat Sing Lecture Theatre, near lift nos. 25/26)
		The Hong Kong University of Science & Technology

Abstract:

We have witnessed an unprecedented explosion in wireless networking
technologies, including WiFi, WiMax, Bluetooth, UWB, 3G, Software Defined
Radio (SDR), etc. These technologies will co-exist in the future to form a
multi-radio wireless environment providing different service abilities to
user applications. With the proliferation of wireless-enabled devices, and
especially multi-radio/multi-band enabled devices, much attention has been
paid to the desire of ensuring 'always best connected' networking. There
are several key challenges. Due to the shared nature of wireless media,
contention from neighboring devices causes interference, which in turn
results in significant system performance degradation. To eliminate
interference between different wireless technologies, current spectrum
allocation policies allocate a fixed spectrum slice to each wireless
technology or service, which results in poor radio resource utilization.
Meanwhile, controls in different layers of wireless networks, such as
access model selection, power adjustment, channel/spectrum assignment,
rate adaptation, scheduling, routing selection, etc. have mutual impact,
which makes radio resource management an extremely tough issue. While it
shows promise, research and development of open spectrum and multi-radio
networking is one of the hottest subjects in this field and is still in
its infancy.

Through studying the unique characteristics of multi-radio wireless
networks, collaborative and cognitive networking (CCN) is proposed to make
the devices cognitive to the environment and adapt to the best performance
by device collaboration. After introducing the scope of CCN, I will
present two concrete technologies, i.e., SoftMAC and JCAR.  To address the
VoIP delivery over wireless mesh networks, Layer 2.5 SoftMAC that resides
between the 802.11 MAC layer and IP layer is proposed to coordinate the
real-time and best-effort packet transmission among neighboring nodes in a
wireless mesh network. Distributed admission control, rate control, and
non-preemptive priority queuing is introduced to regulate the contention
in the mesh networks. Multiple orthogonal channels available in the
wireless networks provide the feasibility for interference mitigation
among nearby access. With many mobile devices being equipped with more
than one radio, especially the heterogeneous ones, these devices will
construct a Multi-radio Multi-channel Multi-hop Wireless Network (M3WN).
To effectively mitigate interference in M3WN, propose a novel software
solution, called Layer 2.5 JCAR (joint channel assignment and routing),
which resides between the MAC layer and routing layer. JCAR jointly
coordinates the channel selection on each wireless interface and route
selection among interfaces based on the traffic information measured and
exchanged among two-hop neighbor nodes.


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Biography:

Dr. Zhang (M'00, SM'04) received the B.S., M.S., and Ph.D. degrees from
Wuhan University, China, in 1994, 1996, and 1999, respectively, all in
computer science.  Dr. Zhang joined Hong Kong University of Science and
Technology in Sept. 2005 as an Associate Professor. Before that, she was
in Microsoft Research, Asia, Beijing, China, from July 1999, where she was
the research manager of the Wireless and Networking Group. Dr. Zhang has
published more than 100 refereed papers in international leading journals
and key conferences in the areas of wireless/Internet multimedia
networking, wireless communications and networking, and overlay
networking. She is the inventor of about 30 pending International patents.
Her current research interests are in the areas of wireless
communications, IP networking, multimedia, P2P overlay, and wireless
security. She also participated many activities in the IETF ROHC (Robust
Header Compression) WG group for TCP/IP header compression.

Dr. Zhang is the Associate Editor for IEEE Transactions on Vehicular
Technologies and IEEE Transactions on Wireless Communications. She also
served as Guest Editor for special issue on wireless video in IEEE
wireless Communication Magazine. Dr. Zhang has received TR 100 (MIT
Technology Review) world's top young innovator award in 2004. She also
received the Best Asia Pacific (AP) Young Researcher Award elected by IEEE
Communication Society in 2004. She received the Best Paper Award in
Multimedia Technical Committee (MMTC) of IEEE Communication Society. Dr.
Zhang is chair of QoSIG of the Multimedia Communication Technical
Committee of the IEEE Communications Society. She is also a member of the
Visual Signal Processing and Communication Technical Committee and the
Multimedia System and Application Technical Committee of the IEEE Circuits
and Systems Society.