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Startup chip pioneers Wi-Fi 'beamforming'
Could get meshy.
By Mikael Ricknäs, IDG News Service
Published: 09:51 GMT, 15 October 08
Startup Quantenna Communications has announced chips it hopes Wi-Fi equipment vendors will use to improve the performance of wireless networking products over the next year.
By integrating technologies such as mesh networking and ‘beamforming' in one match-box sized package, Quantenna wants to make wireless a reliable option for IP-based HDTV in any kind of home, and in the process take on industry stalwarts Broadcom and Atheros, according to CEO Behrooz Rezvani.
The company will start shipping samples of its QHS (Quantenna High Speed) chipset family this quarter, and the first products incorporating its hardware are expected to show up late in the second quarter or early in the third quarter next year. "We have a number of close contacts with both retail based vendors and operators. One of them is Pirelli," said Rezvani.
When it was founded in 2006, the company's goal was to develop a chipset that can deliver data at 100Mbits/s anywhere in any kind of home, but getting there has been far from easy.
Wireless home networking presents different challenges, depending on where you are in the world. In Japan, thin walls in high density, high rise buildings result in interference, while thick European walls and large American homes lead to problems with signal loss and fading, according Rezvani.
To get around all that, Quantenna has combined some tricks of its own (it has filed 14 patents) with existing transmission standards, or in the case of 802.11n, a draft standard.
Quantenna first realised it had to support mesh networking, a technique that allows wireless devices around the home to relay signals to one another in order to reach those furthest from the home broadband connection.
"The signal drops as you get further away from the source point, that's just a mathematical fact. There is nothing you can do about that, and you get around that by using a mesh," said Rezvani. Connecting multiple base stations in a mesh allows them to cover larger areas without diminished performance.
Rezvani sees Quantenna customers developing mesh nodes that looks like the AirPort Express Base Station from Apple, a compact unit that plugs directly into an electrical outlet in the wall.
The AirPort Express, in common with many Wi-Fi products from Apple and other manufacturers, can also relay signals to other network nodes using the industry standard WDS (Wireless Distribution System) - but this is a bridging technology, not a routing one, and so cannot dynamically reroute traffic if a node is removed from the network or is temporarily unavailable due to interference.
Mesh networks, on the other hand, can choose to send data along a different path to get around localized interference issues, Rezvani said.
If companies such as Hewlett-Packard or Dell were to put the mesh algorithm into their laptops, then they too could become part of the mesh: There is more than enough power for that to be done, according to Rezvani.
Besides mesh networking, the QHS family supports transmit beamforming, which makes it possible for the access point to aim its signal at the client. "Beamforming helps when you have difficult walls, and also when you want to get rid of dead spots," said Rezvani.
When a signal arrives at the access point it starts to calculate the direction of the beam, and from there starts estimating its location. It doesn't matter if the client is 802.11b, g or n, according to Rezvani.
The 802.11n standard specifies two ways of calculating the direction: implicit and explicit. With implicit calculation, the access point estimates the direction, while explicit calculation requires the client to support beam forming and also send its location to the access point. "We support both," said Rezvani.
The last two parts in Quatenna's arsenal are MIMO and concurrent dual-band technology, which makes it possible to transmit data via both the 5GHz band and the 2.4GHz band at the same time. Concurrent dual-band is a part of its top of the line QHS 1000, which supports data rates of up to 600Mbits/s, according to Rezvani.
The dual-band system should help Quantenna achieve its goal of reliable HD video distribution over home networks: "You can put the data on 2.4 GHz and the video on 5 GHz," said Rezvani.
MIMO is the cornerstone of 802.11n, helping get the signals through high-interference conditions, according to Rezvani.
To be able to do both beam forming and MIMO you need several antennas and to do it well you need at least four, which is what the QHS family supports, according to Rezvani.
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