Wireless meshes: disruptive technology coming your way

Wireless mesh networks have the potential to disrupt the existing telecom set-up, say Jerome Buvat, Manager, and Ashish Sidhra, Senior Consultant, CapGemini Telecom and Media Strategy Lab, London / Mumbai.

Throughout the history of the telecommunications sector, new technologies have evolved that offer the user superior value. The telephone replaced the telegraph, wireless surpassed fixed line, and VoIP evolved to replace circuit-switched technology. These events bear testimony to the fact that telecom is a breeding ground for disruptive technologies.

Ashish Sidhra

True to this historical trend, a new technology is knocking on the doors of the telecom industry—the wireless mesh network.

Like many of its predecessors, this technology has significant potential to disrupt the current telecom setup. Let us look at what makes mesh networks disruptive. We will also explore the imperatives for the success of this technology, and its possible evolution over the next couple of years.

Mesh Networks

Jerome Buvat

Wireless mesh networks are peer-to-peer wireless communication systems that let two devices communicate directly, instead of being routed through a central switch.

Unlike in a conventional network, end-user devices in a mesh network, in addition to sending their own data, act as routers or repeaters relaying signals for other devices. The routing information of a conventional network resides in the central switch, whereas this intelligence is distributed among the mesh entities, making it decentralised.

This allows each meshed transmitter node to relay signals to several other nodes, as opposed to conventional transmitter nodes, which talk to each other through the central switch.

Additionally, backhaul communication of mesh networks is over the air, requiring substantially less wiring than a conventional network to connect the transmitter nodes to the central switch.

Mesh Architecture

Vendors are offering mesh solutions under two basic architectures that try to balance network scalability with throughput.

The network mesh creates a wireless mesh only among transmitter nodes. In such networks client devices do not relay data for other devices. This semi-mesh, by virtue of dumb-user devices, restricts the number of transmitters, permitting low routing signal overheads.

The client mesh, on the other hand, enables a wireless mesh among the client devices in addition to the transmitter nodes, allowing them to relay data for other devices. The true mesh allows the creation of peer-to-peer networks, improving coverage and the robustness of the network. A few vendors are backing this architecture with proprietary routing algorithms.

Motorola is one such vendor offering a client mesh architecture via its wireless PCMCIA cards. Most vendors offer a semi-mesh architecture because their routing algorithms do not support the huge signalling overheads associated with a large-scale, true mesh deployment.

Wi-Fi Finds Favour

Mesh protocols are frequency-agnostic, and can be used with technologies such as Wi-Fi, Bluetooth, Zigbee, and Ultra-wide band (UWB). However, with the growing customer uptake of 802.11 Wi-Fi, vendors are increasingly using these standards for implementing mesh networks.

Wi-Fi-based mesh networks enable customers to continue using existing Wi-Fi devices without hardware or software upgrades. The growing use of Wi-Fi devices is likely to boost the deployment of Wi-Fi-based mesh networks.

The strong value that mesh networks offer the user and the substantially lower entry barriers for greenfield operators have prompted the uptake of this technology as an alternate solution for offering broadband services. This is what makes it potentially disruptive for incumbent operators.

User Value Proposition

On the demand side, mesh networks offer substantial benefits to users in terms of better features, lower costs and an enhanced experience.

The peer-to-peer nature of mesh networks encourages users to set up their own networks, with each participant in the network owning and maintaining its own hardware. This allows some customers to bypass operators for local communications.

Users get download speeds of 3x–6x cable/DSL, and about 12x–15x data speeds compared to a conventional 3G network. Mesh networks based on UWB are slated to provide data speeds of up to 400 Mbps.

Mesh wireless broadband offerings are available at nearly a fifth of cellular data prices, one-third of DSL/cable price points, and at nearly half the price of Wi-Fi offerings, with faster installation at a lower cost due to the reduced cabling requirements.

With mesh networks, users need not search for hotspots as they get a city-wide, fully-mobile, broadband connection. Mesh network customers get to experience a higher quality service as high network redundancy prevents the link drops and outages which are common in other wireless networks.

Lowered Entry Barriers

Mesh networks enable operators to shorten service-launch timelines by overcoming regulatory barriers. With their frequency-agnostic properties, mesh networks can be launched on licence-free technologies like Wi-Fi. This enables operators to bypass the prolonged process associated with spectrum allocations for commercial use.

Unlicenced spectrum and the absence of an expensive wired backbone enable operators to set up mesh networks with much lower capital expenditure than networks based on other technologies. Automatic configuration and topology selection enable low maintenance and operational costs.

In addition, due to the shorter transmission distances involved, mesh transmitters consume less power compared to other wireless technologies.

Dynamic routing and no central point of failure enable the networks to operate even if nodes are removed or damaged. Mesh systems use dynamic node discovery and automatic selection of topology to install and integrate the nodes without further configuration requirements. Mesh technology lowers entry barriers for greenfield operators, enabling players to challenge incumbent cellular and broadband operators.

Mainstream?

The past few months have seen increased deployment of mesh networks around the world. As a true disruptive technology, mesh networks are largely being deployed by new entrants like greenfield operators and community-based network players.

According to industry estimates, around 100 municipalities around the world are using mesh-based networks in one form or the other.

However, not all innovations identified as disruptive succeed in entering the mainstream. Disruptive technologies have had their own fair share of successes and failures. While VoIP, ADSL and digital cameras are some of the much publicised successful disruptions, the cases of Betamax or laserdisks vs. VHS are two classic failures of disruptive technologies.

Success Parameters

If we analyse mesh networks against these parameters, we find that the following factors will help the technology move to the mainstream.

User appeal: Mesh networks have an established primary target audience in large geographical pockets still waiting to go broadband live. They have already generated successful references for commercial deployments in niche segments, and are now moving towards large-scale city-wide deployments.

Partner ecosystem: For mesh networks to become mainstream, an ecosystem of equipment vendors, application providers, CPE

manufacturers and operators has to evolve to establish a robust value chain. It is imperative that R&D support be maintained or even raised to higher levels for improving current performance levels.

The mesh phenomenon has started to gather steam, and big players such as Motorola and Nortel have joined the mesh platform in the past few months. Large Wi-Fi operators like Boingo have also begun tying up with mesh-based service providers.

Standards and regulations: All current mesh offerings are based on proprietary protocols and are not inter-operable with each other. This may hinder faster uptake of the technology because the incompatibilities between proprietary networks will prevent groups of mesh users from communicating with each other directly.

That said, progress has been made towards standardisation by setting up a new IEEE task group in July 2004. This group is working on wireless mesh standards known as IEEE 802.11s. Publication of these standards is estimated to be at least three years away.

When used with Wi-Fi standards, mesh networks do not face any regulatory challenges as the 2.4 GHz band is globally licence-free. As for the 5 GHz frequency band, although it is an unlicenced band in Europe, some countries do not allow its outdoor use.

Security Issues: Since most current implementations of mesh networks are based on Wi-Fi, questions are bound to arise on the security aspect. To counter this, mesh vendors claim they have developed protocols providing built-in security mechanisms like advanced encryption on the backbone link and user authentication. Additionally, work is already in progress to incorporate the IEEE 802.11i security standards into Wi-Fi mesh products.

Technological Stability: A large city-wide mesh network may have its bandwidth choked by too many routing information updates. Similarly, the ability to maintain low latencies over multiple hops is an area of concern. Sustained bandwidth availability with low latencies is a must for providing services like Video on Demand (VoD) and VoIP.

Solutions On Offer

Vendors have come up with innovative solutions to overcome these issues. On offer are multi-radio solutions to provide sustained bandwidth, and software suites to create QoS solutions for applications like VoD and VoIP. However, to date there is no installation large enough to substantiate the claims.

Give It A Couple Of Years

Mesh technology possesses most of the necessary success drivers, and work is continuing to resolve the remaining glitches. As barriers are removed over the next few years, and as the technology evolves, ironing out performance issues, the disruptive potential of mesh networks will grow in scale and scope.

It is possible that 2005 will see niche segment mesh implementations give way to increased deployments of large-scale, city-wide broadband networks. By 2006, based on the performance results of broadband deployments in cities like Taipei and Philadelphia, we can expect the number of greenfield operators to mushroom globally, trying to replicate the success.

The biggest trigger for mass deployment of large scale mesh networks will be the availability of the 802.11s standardisation in 2007 which will bring the true disruptive potential of these networks to fruition.