October 2006 newsletter

Oct 2006 Newsletter: from Archan Misra, Chair TCCC

Dear TCCC colleagues,

I hope this edition of the newsletter finds all of you in high spirits and good health! The TCCC executive committee has been busy the last few months with various organizational matters and I believe we’ve been making good progress towards our underlying goals. This newsletter contains the following items and updates:

  • Introduction of recently-inducted TCCC ExCom members
  • Up-to-date call for participation/papers for TCCC sponsored conferences
  • Report on the organization and conduct of WoWMoM 2006
  • A news article by Prof. Young-bae Ko, explaining ongoing IEEE activities in the hot area of “wireless meshes” (arranged by the efforts of Sunghyun Choi, the Untethered Technologies chair). Sunghyun, thank you for your efforts!

As always, please feel free to browse the newsletter (also available from our Website: http://tab.computer.org/tccc/) and let us know your opinions and feedback. We shall also be adding a few new features to our Website in the next couple of months, which I hope will increase its interactive nature and foster a greater sense of community. I’ll heave more to say on those issues in the next newsletter.

Archan Misra
TCCC Chair


I am pleased to inform you of the continuing expansion of our Executive Committee. As you may recall, one of my stated priorities was to expand the diversity of the ExCom, with an attempt to providing breadth in both geographical reach and expertise.
With this in mind, I’ve pleased to report on the addition of several well-known and eminent professional colleagues the ExCom.

Prof Joerg Ott (from Helsinki University of Technology, Finland) shall serve as the “Multimedia Network Technologies” Chair. Prof Ott is an expert on various multimedia signaling technologies (such as SIP), as well as on the emerging area of delay-tolerant networks. Moreover, Prof. Ott is also active in the IETF and shall provide us with a better view of standardization activities and industry interests.

Dr. Frank Huebner (from AT&T Labs, USA) has agreed to serve as the “Finance Chair”. In this capacity, he will coordinate the financial planning of our activities and be responsible for the many facets of bookkeeping that require significant diligence and time. Being aware of Frank’s management and negotiations skills (displayed in the organization of the LCN conference), I am sure he will be a great asset to us.

Prof. U. B. Desai (from IIT Bombay, IIT) joins us as a “Member-at-Large”. He is a stalwart in the wireless community and widely respected across India, Europe and the US for his activities related to Bluetooth, and more recently, 802.16. His guidance and leadership should greatly help expand our activities within the vibrant technical community in India and Asia. Finally,

Mr. Iqbal Mohomed (from University of Toronto, Canada) shall serve as our Webmaster. I shall look to him to provide the boost needed to introduce various forms of interactivity to our Web presence. I thank all of them for their volunteerism.


We encourage you to participate in the TCCC-sponsored following conferences that have some deadlines/dates of current relevance.

  1. Call for Papers: 8th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM) 2007, June 18-21,2006, Helsinki, Finland.http://ieee-wowmom.tml.hut.fi/ Deadline for (conference) paper submission: November 19, 2006.

  2. Call for Participation: 14th IEEE International Conference on Network Protocols (ICNP) 2006, November 12-15, 2006, Santa Barbara, USA.http://www.ieee-icnp.org/2006/Besides the main conference, ICNP 2006 includes the 2nd Workshop on Secure Network Protocols (NPSEC).

  3. Call for Participation: 31st IEEE Conference on Local Computer Networks (LCN), 2006, November 14-17, 2006, Tampa, USA.http://www.ieeelcn.org/LCN 2006 includes five additional workshops, on topics including sensor networks, measurements, mobile and wireless computing and network security.

New Sponsorship: As part of our promised effort to extend the TCCC’s support for new activities, I’m also happy to announce the extension of TCCC sponsorship to a new conference on Wireless and Mobile Computing, Networking and Communications (WiMob) from 2007. The preliminary details of the WiMob conference are available at http://www.gel.usherbrooke.ca/WiMob2007/. (More details will follow in due course of time.)


Archan Misra, IBM Research

The 7th International Symposium n a World of Wireless, Mobile and Multimedia Networks (WoWMoM 2006) was held from June 26-29, 2006 at the lovely border town of Niagara Falls, USA. From the approx 140 papers submitted, the technical program consisted of 15 technical sessions, consisting of 15 extended papers, 32 regular papers and 11 poster presentations.
Two of the more prominent themes emerging from the conference technical track were a) the importance of multimedia traffic management (including rate control and cross-layer optimizations) for a variety of wireless applications and b) the heightened importance of security (included intrusion detection, location hiding etc.) for sensor-network based applications. Interestingly enough, the support of a combination of interactive and broadcast multimedia traffic seems to be the main technical challenge for emerging cellular and mesh network architectures—several papers highlighted the enhancements that would need to be at the MAC and routing layers. There was also significant audience interest in several well-known problems related to sensor networks, with a noticeable trend towards research in various “middleware” aspects of sensor networks (besides the traditional focus on MAC and routing layer issues).

Some of the interesting papers at the conference included “Entrapping Adversaries for Source Protection in Sensor Networks” by Y. Ouyang. et al (which describes a technique for inserting low-latency loops in the data delivery path to shield the location of a source sensor from an eavesdropping adversary), “Mobile Element Based Differentiated Message Delivery in Wireless Sensor Networks” by Y. Gu, D. Bozdag and E. Ekici (which describes how the travel schedule of mobile elements or data mules can be orchestrated to address differential QoS tolerances in the generated data), “Some Insights from Bounds on UWB Sensor Localization” by S. Venkatesh and M. Buehrer (which relates the accuracy of localization to enhancements at the MAC layer to permit high throughput of packets containing range estimates) and “An Energy-Efficient Forwarding Scheme for Wireless Sensor Networks” by M. Busse, T. Haensselman and W. Effelsberg (which shows how a new multi-link data forwarding approach, where a single transmission reaches multiple receivers, can improve the energy efficiency and lifetime of sensor networks).

The conference program included two, extremely well-received, keynote speeches. The first keynote speech titled “Multimedia Content on Mobile Devices: Opportunities and Challenges” by Dr. Kumar Ramaswamy (VP, Corporate Research,Thomson) focused on the challenges and issues related to multimedia delivery by cellular providers in a converged network provider. Dr. Ramaswamy highlighted the importance of the increasingly popularity on broadcast multimedia interactions (e.g., mobile TV via technologies such as DVB), and argued that interactive multimedia traffic would emerge as a value-added service over the basic broadcast traffic, presenting several challenges for integrated signaling, service creation and service management. The second keynote speech titled “Networking in a Heterogeneous, Intermittent World” by Dr. Kevin Fall (Principal Engineer, Intel Research) presented a fascinating overview of the emergence of delay, mobility and disconnection tolerant applications as a new paradigm of communication in a variety of scenarios. His talk highlighted how DTN scenarios resulted in new research challenges in both protocol modification and application design, and also presented newly emerging research on the applicability of DTN techniques to underwater marine networks.
In addition, WoWMoM 2006 also featured a very lively panel discussion on “Integrated Optical and Wireless Technologies for Broadband Access and Metro Networks”, which highlighted how advances in broadband amplifiers and other technologies could lead to tighter integration between a fiber-wired backbone and a wireless-based metro access network. WoWMoM 2006 was collocated with a set of five very successful workshops, including themes related to “autonomic communications” “experimental evaluation of wireless networks”, “distributed computing techniques in mobile applications”, “middleware components for sensor networks” and “trust and privacy in pervasive environments”. Each of these workshops attracted a focused and lively audience and generated significant discussion and debate on emerging research trends in specific niche areas.

Next year, the 8th edition of IEEE WoWMoM will be held in Helsinki, Finland on June18-21, 2007. Look forward to everyone’s participation in this conference!

Multi-hop Relay/Mesh Technology in IEEE 802 standards

Young-Bae Ko, Ajou University, Rep. of Korea

(This article was written by Prof. Ko, Asst. Professor in the School of Information and Computer Engineering at Ajou University. Prof. Ko’s areas of interests include wireless networking protocols, radio technologies and ubiquitous computing. He is an expert on wireless networking protocols and was the recipient of the Best Student Paper Award in Mobicom 1998).

Wireless communications such as Wi-Fi and broadband wireless access (BWA) are gaining widespread popularity for constructing the local and wide area networks. The virtue of wireless medium has simplified the tedious or sometimes even impossible task of running cables, thus also reducing the cost and complexity of installation. However, the key question of whether the current wireless technologies can effectively replace their wired counterparts still remains at large, with the reason being the dependency on the wired infrastructure and some inherent limitations imposed by single-hop wireless communication architecture. For example, the legacy IEEE 802.11 WLAN still requires wire-line infrastructure, making the technology expensive and time consuming to deploy. Also, its network performance degrades sharply with the increasing number of users, failing to comply with the economy of scale. Hence as a better alternative, a multi-hop relay/mesh technology is proposed, with the advantages of higher data-rate, capacity enhancement and ease of deployment, and so on. In this context, the IEEE-SA (standard association) has established several task groups for adopting wireless multi-hop relay/mesh techniques, among which are the IEEE 802.16a, IEEE 802.16j, IEEE 802.11s, IEEE 802.15.4 and IEEE 802.15.5 covering from wide to small area networks. Here, we mainly focus on the two task groups, IEEE 802.16 and IEEE 802.11, and briefly describe their aims, scopes and the current status. The figure below shows the medium access control (MAC) and the physical layer (PHY) of the related projects.

MAC and PHY standards for supporting (1) multi-hop relay system and mesh mode in IEEE 802.16 fixed and mobile broadband wireless networks (2) multi-hop mesh network in IEEE 802.11 wireless local area networks

WMAN Relay/Mesh - IEEE 802.16a & j

The legacy IEEE 802.16 standard provides the specification for the fixed broadband wireless access (FBWA). With bandwidth of up to 75 Mbps, it uses both licensed and unlicensed frequency bands between 2 and 66 GHz. The IEEE 802.16 WG has set up IEEE 802.16a and IEEE 802.16j TGs, in order to apply the concept of multi-hop wireless communication for both fixed and portable/mobile BWA in metropolitan areas. First, the IEEE 802.16a standard incorporates two different modes of communication, namely, a point-to-multipoint (PMP) and the mesh mode. PMP mode strictly requires all SS to connect to the base station (BS), whereas Mesh mode enables the mesh architecture such that the neighboring SSs can directly communicate with each other. For multi-hop mesh creation, each SS acts as a router and forwards traffic from one to another, until it arrives at the mesh-BS. It operates at the 2-11GHz frequency band that allows non-line-of-sight (NLOS) communication in both licensed and license-free spectrum. Internal routing between SSs is also allowed if it is not required to send traffic to the BS but to some destination SS in the same mesh. A mesh-BS connects the mesh network to backhaul link and other external networks. For data transmission, it requires a single path selection protocol between the nodes. However, the mesh mode in IEEE 802.16a is not backward compatible with the already existing PMP mode, and hence fails to extend the capacity and the coverage provided by the existing setup. The IEEE 802.16j, which is currently being developed, aims to enhance PMP architecture by involving relay station (RS) between the BS and the SSs, thereby introducing the multi-hop communication.
The project shall amend and specify new methods that shall increase capacity, extensibility and the scalability of the existing legacy setup. The scope of this project includes the specification of the base station (named MMR-BS) and the relay stations, but shall refrain from any modifications to SSs. Since the creating of TG on March 2006, the IEEE 802.16 TGj is now under the process of preparing the baseline documents for creating the standard. The specification is expected to be adopted as a part of the working group standard by the end of 2007.

WLAN Mesh - IEEE 802.11s

The IEEE 802.11 family of standards is currently the most successful wireless networking standards that defines PHY and MAC sublayer for WLAN devices. The working group continues to advance with various amendments, e.g., 802.11e for QoS and 802.11n for higher data rates. However these standards are still lack of wireless distribution system (WDS) specification and include some possible drawbacks of throughput degradation and unfairness when applied to multihop networks. The IEEE 802.11s ESS mesh aims at applying multihop mesh techniques to specify a wireless distribution system (WDS) to build a wireless infrastructure for the small to large scale WLANs. The ESS Mesh can be considered an IEEE 802.11-based WDS, a subset of the distribution system (DS) interconnecting the access points (APs), such that the end-user stations can exploit the efficient mesh backhaul for sending and receiving the data traffic. The activities of 802.11s TG consists of specifying a new protocol suite for the installation, configuration and operation of WLAN Mesh. Its implementation shall be atop existing PHY layer of IEEE 802.11a/b/g/n that operates in the unlicensed spectrum of 2.4 and 5 GHz frequency bands. The specification shall include the extensions in topology formation to make the WLAN Mesh self-configure as soon as the devices are powered up. A path selection protocol shall be specified in the MAC layer instead of network layer for routing data in the multi-hop mesh topology. This standard is expected to support MAC-layer broadcast/multicast in addition to the unicast transmissions. The standard shall also accommodate devices that are able to support multi-channel operations, or are equipped with multiple radios, with an aim to boost the capacity of the overall network. The specification is expected to be adopted as a part of the working group standard by March 2008.