MeshTech'11

Fifth IEEE International Workshop on
Enabling Technologies and Standards for
Wireless Mesh Networking

October 17, 2011. Valencia, Spain

co-located with IEEE MASS 2011

Background

Wireless mesh networks have emerged as a key technology for next-generation wireless networking. A wireless mesh network is characterized by dynamic self-organization, self-configuration and self-healing, allowing easy and fast, highly scalable, reliable and cost-effective network deployment under very diverse environments, and provision of better coverage and capacity to stationary and mobile users. Because of this, wireless mesh networks have not only become a hot topic in the research community, but are also experiencing a rapid proliferation in many of today’s environments.

Technical Scope

Several standardization bodies specify MAC layer protocols and architectures for interoperable Wireless Mesh (IEEE 802.11s, and IEEE 802.15.5) and Relay Networks (IEEE 802.16). At the Network layer, IETF related groups (e.g. MIPSHOP, NETLMM and MANET Working Groups) develop technologies in the context of wireless access and mobility support for the Next Generation Internet. These standards mainly address the following scenarios:

• Public city-wide, rural, and private business broadband access as well as neighborhood communities: These networks are characterized by frequent topology changes, faults in equipment, and/or harsh environmental conditions.
• Military and emergency usage: While the aforementioned networks almost always have access to external networks, mesh networking in disaster areas leads to different topologies where a mesh network needs to operate autonomously under any circumstances.

With its 2009 economic stimulus package, the U.S. government encourages increased energy efficiency. Several research and standardization groups have taken up the initiative and work on wide area communication technologies that help to evolve a smart grid. This scenario is characterized by the following:

• Smart grid: Today's utility networks consist of dump pipes that leave suppliers without any information of the grid’s usage. Smart grid technology, however, helps to overcome the information gap and paves the way towards a decentralized grid topology. Intelligent meters, transmission, distribution and demand based charging may help to prevent blackouts and stabilize the network load. Accordingly, wide area communication technologies are called for to enable a distributed network topology that is necessary to signal the current grid utilization and energy demands. As diverse as the utility networks are, as diverse the communications infrastructure will be. It is likely, that the smart grid will be one of the first mesh of mesh networks.

On the consumer side, ever faster and more powerful technologies are in more and more devices: Digital cameras, smart phones, netbooks and other electronic gadgets are required to exchange anytime, anywhere. New topologies alternative to the classic, base-station centred ones are required. Accordingly, so called "single hop" mesh networks and demand for other ad hoc networks emerge:

• Next generation Bluetooth: Since IEEE 802.11n offers PHY speeds of up to 600 Mb/s, the Bluetooth SIG has decided to base its next generation specification on the foundations of 802.11. Bluetooth 3.0 can offload data to 802.11 links. While encryption keys and authentication data rely on the classical Bluetooth radio, the 802.11 link carries data on request only, thereby forming spontaneous ad hoc networks. A network consisting of heterogeneous technologies is formed.
• Wi-Fi Direct: Wi-Fi Alliance (WFA) has developed a peer-to-peer specification that targets at Bluetooth like deployments, so as to allow for a private network to be easily set up. Devices may spontaneously operate as an Access Point for others while at the same time maintaining the client role within a different network. Consequently, devices operate in multiple networks simultaneously.
• Direct Link Set-up: IEEE 802.11 Task Group "z" is in the process of publishing its amendment that enables direct link connectivity between end stations, thereby avoiding unnecessary transmissions to and from an Access Point. Similarly, the WLAN Mesh draft 802.11s itself offers a non-forwarding mode where devices communicate locally only. Common to both is their independence of a central station and their impact on throughput, delay and medium sharing of wireless medium.

With the emergence of these novel topologies, wireless mesh networks and their ad hoc relatives have become a hot topic in the research community. However, these new topologies affect protocol designs and interoperability with existing networks. Loop-free set-ups, broadcast traffic handling, inter and intra-standard connectivity, and hand over of roaming devices are a few examples that these new technologies need to be aware of. Furthermore, it is still to be fully understood what technological challenges the above-mentioned standardization efforts will face, how they evolve, and what application scenarios will drive their possible success in the market.