JUST MARRIED: MESH AND POINT-TO-MULTI-POINT

SkyPilot Networks is showing up to the municipal wireless network party a little bit late, but the company is trying to make up for it by bringing a dish the guests haven't tried yet. The 5-year-old Santa Clara, Calif.-based company, a broadband wireless equipment vendor that traditionally has been a supplier of point-to-multipoint fixed wireless gear, is launching its first product effort in the burgeoning market for municipal wireless mesh networking. That platform, the SkyExtender DualBand, is a dual-band radio mesh architecture based on a marriage of the company's synchronous mesh protocol and advanced antenna array technology. These two technologies, in turn, take many cues from traditional mesh and point-to-multipoint network architectures, and SkyPilot's product looks like the first — though probably not the last — to combine the strengths of both.

Though other companies have mesh and point-to-multipoint technology assets, Brian Jenkins, vice president of product management at SkyPilot Networks, said the integration is not easy.

“We're combining two very different topologies in our synchronous mesh protocol. It took us four and a half years to really get the integration of mesh and point-to-multipoint right,” he said. “If the market is trending toward a dual-radio solution, that also makes it more expensive for the single-radio guys to produce a new architecture.”

The SkyExtender DualBand operates in the unlicensed 5.8 GHz band and the 4.9 GHz band for public-safety communications, with dedicated access via 2.4 GHz Wi-Fi, to avoid interference with the backhaul portion of the network. Most first-generation mesh architectures aimed at municipal applications have been single-band solutions, in which backhaul and access use the same 2.4 GHz frequency. Now, after a couple of years during which mesh networking has begun to gain traction, and during which the list of major municipalities pursuing wireless networks has grown rapidly, dual-band solutions like those from Strix Systems and now SkyPilot represent a second-generation approach to mesh networking.

“You really can't use one radio for access and for backhaul as well; you need a second radio,” said Chuck Haas, founder, president and CEO of MetroFi, a builder and operator of municipal wireless networks that is using SkyPilot's new SkyExtender DualBand system in deployments in Santa Clara and Cupertino, California.

While other dual-band solutions have begun to emerge from other vendors, Haas said that SkyPilot brought an important variation to the table — it is capable of multiple hops necessary for applications such as voice over IP (VoIP), a service that MetroFi wants to offer. Some mesh architectures are only single hop. “We looked at a few other dual-band solutions, but we wanted to be able to have three or four hops with low latency and high throughput,” Haas said. “You need a mesh architecture with hops to be able to run VoIP.”

SkyPilot's Jenkins said that while VoIP probably isn't a popular municipal wireless network application just yet, SkyPilot's approach also claims an economic edge to which all municipalities and their network builders can relate. The solution's cost of deployment is about $1800 per node, which the company says is at least half the cost of other dual-band products.

“There is definite pressure from municipal operators to keep cost in check, though scalability is important, too,” Jenkins said. “There are a lot of other municipal wireless network opportunities available outside of the biggest cities, and they consist of a variety of needs and economic models.”

“We have to sell broadband for $20, and that's the reality of the situation,” Haas said.

SkyPilot's dual-band radio approach may fit the description of a second-generation municipal mesh networking architecture, but the company also has already set its sights on the third generation. Last month, the company announced that it had chosen Fujitsu Microelectronics America's WiMAX system-on-a-chip to power a WiMAX mesh solution SkyPilot has under development for a planned launch next year. SkyPilot's current plan is to create an architecture employing the capabilities of the 802.16d-2004 standard, and having the platform ready in April 2006. That product will use WiMAX in the backhaul portion and Wi-Fi for access. While Intel and others are touting the eventuality of WiMAX all the way to the end user, it could be years away.

“We will continue to evolve our backbone to WiMAX, but [802.11b Wi-Fi] to the end users will be around for a while, and maybe forever,” Haas said.