Airlines to get a multichannel WLan chip boost

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Airlines to get a multichannel WLan chip boost

Chipsets from startup Engim which allow one Wi-Fi access point to carry data on multiple channels may end up in networks optimised for high-density environments, including multipurpose wireless infrastructures on airliners.

The company will introduce its new generation of both silicon and access points for suppliers to incorporate into wireless Lan offerings.

Engim's EN-3001 Wideband Wireless Lan chipset and access point reference designs for 802.11b and 802.11g are designed to use three channels at once, allowing more clients within a single area to simultaneously use Wi-Fi, according to Scott Lindsay, vice-president of marketing at Engim.

Engim is adding to its lineup a thin access point, priced to system makers at about $100, in which the processing of packets takes place in the chipset rather than on a separate processor. Also new is a feature in Engim's radio chip called "transmit cancellation", which can prevent interference that an access point's transmitting antenna can cause to the same access point's receiving antenna, Lindsay said. The feature subtracts the transmit antenna's interfering signals for the receiving antenna.

At the heart of Engim's approach is multichannel capability. The 802.11b and 802.11g standards use spectrum in the 2.4GHz band that offers at least 11 bands, but generally only three of those can be used because of interference from channel overlap. Each access point typically can only use one of those channels, and simply putting three access points in one location with each on a different channel - or just building an access point with three chips on different channels - will not provide good performance because they will interfere with each other, Lindsay said.

That means the zone covered by an access point, typically about 300ft, can only be served by one channel, leaving two channels unused, said analyst Craig Mathias, founder of Farpoint Group. That is a waste of spectrum, he said, one that is not a big problem today but is likely to become one in the future.

Engim built the silicon for three channels into a single chip, with technology that can find the interference on a channel and subtract it out for a clear signal, Lindsay said. A radio for 802.11a, due in two or three months, will allow the use of three 802.11a channels simultaneously.

One of the dense environments that may benefit from Engim's approach is airliner cabins, according to Jim Pristas, founder and chief executive officer of Matrx Aerospace Broadband Technologies.

Matrx is using Engim's chipset in the demonstration unit of an in-flight wireless infrastructure it is developing, called Galaxy. Matrx plans to work with airlines, aircraft manufacturers and other partners to install the systems, Pristas said. Matrx was founded in 2001, and is backed by a major aerospace company, although he would not identify the company. 

Galaxy will be able to use multiple wireless bands as well as multiple channels within each band, according to Pristas.

The company aims to start out in late 2005 with a version geared primarily to passenger web access and e-mail over Wi-Fi. Those services are already offered on some airlines, but because Galaxy will be built specifically for airplane cabins, it will offer better performance, in part because of the multichannel capability, Pristas said.

A second version of Galaxy, aimed for 2006, would offer a wider range of services through a system that could include proprietary wireless systems in addition to Wi-Fi, Pristas said.

The system might also be used for surveillance cameras, crew communication, handheld point-of-sale devices and other applications. The performance advantages of the purpose-built system could also serve another future application, in-flight wireless phone calls, he said.

Prices for the EN-3001 chipset will vary based on volume and the customer's development needs. The chipset, as well as the AP-310 All Services Access Point at about $120 (£65) and the AP-320 Thin All Services Access Point at about $100, are available immediately to system suppliers.

Stephen Lawson writes for IDG News Service


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