Tropos Goes Multi-Radio

By Eric Griffith

August 17, 2006

UPDATED: The primary complaint about Tropos MetroMesh equipment is obsolete with the debut of a dual-radio 11a/g node.

It's hard to argue with Tropos Networks' success. Take, for example, a few hundred deployments worldwide and partnerships with providers on some of the most-hyped metropolitan-scale wireless networks ever (i.e. EarthLink, with Philadelphia, San Francisco and elsewhere). Yet it has always taken knocks for being the lone mesh equipment provider utilizing just a single radio to perform both the client connection and the backhaul mesh.

That won't be the case come October, when the company starts shipping the Tropos 5320 MetroMesh Router. It’s the company’s first to include both a 5GHz 802.11a radio and a 2.4GHz 802.11b/g radio. And unlike the competition, which usually segments them so that one is for backhaul and the other is for client connections, Tropos has upgraded its software so either radio can do either job, on the fly.

The embedded MetroMeshOS software that runs the products will "cover multiple radio frequencies for alternate paths," says Brad Day, manager of marketing communications for Tropos. "Since its inception, MetroMeshOS was meant to be access method independent. We've enhanced that."

"Everyone has said, 'You need multiple radios,' but we've disagreed," Day says. "Our position was, hardware in a box doesn't solve anything. You need to efficiently use it... we used software to make efficient use of the spectrum."

Day also extols the MetroMesh routers' easy installation as something that "can be done by a trade-level employee with a screwdriver in 15 minutes," without aiming antennas.

Using the Tropos Predictive Wireless Routing Protocol (PWRP) "We can automatically and dynamically find the frequency band to get the highest throughput on the mesh," says Day. "There might be areas where 5GHz works well with line-of-sight or less obstruction, and MetroMesh will pick that. But there might be times when that is unclear — could be leaves on trees, some other interference — and it goes to the 2.4GHz band to establish and maintain the best performance."

Right now, this dynamic radio switching is for the mesh backhaul only, but as more client types are available on laptops — say you have a computer with not only Wi-Fi but also EV-DO or even WiMax capabilities — Tropos says it would only take a software upgrade to make the upgrade to dynamic client radio switching. Whether the company bothers or not will depend on demand.

Taking a dig at the competition, Day says, "Most multi-band products are dedicated — one for the client, one for [inter-mesh communication]... Our solution is unique. And it is compatible with all existing MetroMesh routers. Install a new 5320 in an existing deployment, and they're compatible." (Though it'll only talk at 2.4GHz until there's another 5GHz node around to play with.) All of this is invisible to the user and service provider.

Day also says that in a typical urban or suburban mesh deployment, due to interference and the vagaries of the 5GHz frequency, only about 50% of 802.11a links will "close" (as in, only half will connect). He says you need a higher node density to get 100% link closure with 802.11a radios on the mesh, which costs three to four times as much with the competition.

"It imposes a 'tax' on a customer to get intra-mesh connections to work," says Day. "We can deploy the new 5320 routers at the same density as the 5210, and achieve the 1.5 to 1.7 times increase in capacity."

The competition at BelAir Networks says the latest from Tropos is too little, too late. BelAir co-founder and CTO Stephen Rayment says his company already delivers dynamically created multi-band paths, and that it already has three times the capacity at the same price as single-radio mesh products (namely, Tropos). "Tropos claims that in future software releases they might support clients on 5GHz, and that they expect to deliver 4.9GHz public safety band radios within the year, and that future devices could include directional antennas, and that they are 'watching WiMAX,'" Rayment says. "Again, BelAir is already delivering all of the above."

Tropos doesn't talk dollar figures about its products, but says the 5320 will cost 30 to 40 percent more than the current single-radio 5210 units -- which Day claims is still lower in cost than the competition.

Success with the 5320 will lead to other MetroMesh hardware over the next year, with radios supporting anything from WiMax to 4.9GHz (reserved for public safety) to MIMO/802.11n to 3G/4G. With the "radio agnostic" MetroMeshOS, the company says the sky is the limit on what it could support.

Tropos is also willing to build products to order for the holders of licensed radio spectrum through its new Tropos Metro Wireless Development (TMWD) program. Day says MetroMeshOS will work with any of them.



Comment and Contribute
(Maximum characters: 1200). You have
characters left.