NEWS: Startup details video-grade Wi-Fi chip
Switched MIMO helps Celeno support four HD streams
By Rick Merritt
EE Times
(09/08/08, 12:01:00 AM EDT)
SAN JOSE, Calif. — Startup Celeno Communications Ltd. (Ra'anana, Israel) is providing the first details of its new 5 GHz Wi-Fi chip that aims to support multiple high definition video streams for carrier-class set-top boxes and gateways. The CL1300 can manage up to four simultaneous high def stream over 50 meters though multiple walls and floors without losing packets, the company claims.

Celeno's effort differs from previous startups that tried and failed to craft versions of Wi-Fi for video-grade home networks. Rather than create non-standard quality of service techniques that must be used on both end of a link, Celeno's chip is compatible with 802.11 a/b/g/n chip sets and can achieve its stated performance when paired with any Wi-Fi chip set.

The CL1300 uses multiple techniques to bolster the best-efforts nature of Wi-Fi. Its physical layer supports up to eight MIMO antennas that use a form of triangulation to locate and form a directional beam to other Wi-Fi devices.

The chip then uses a so-called Switched MIMO algorithm to track the quality of the link and switch the number of antennas used for transmit and receive work as needed. It uses only 20 MHz channels at 5 GHz to reduce the potential of interference if it employed 40 MHz channels or used more crowded 2.4 GHz bands.

An embedded ARM9 processor is responsible for maintaining throughput guarantees with each client based on its class of service. The CPU assesses the quality of the link every 10 millisecond processing cycle, scheduling transceiver functions as needed to maintain link quality.

Finally, a homegrown packet processor on the chip inspects packets to gather data about classes of service. The resulting 130 nm chip includes a full MAC and PHY and can run with as little as 16 Mbytes external DDR2 memory.

The CL1300 can maintain 35 Mbits/s UDP throughput across 23 meters and five walls before throughput begins to decline, according to Celeno's tests. A competing 802.11n chip set saw performance decline at 13 meters and two walls and lost connection at 21 meters and four walls in the tests.

"802.11n just doesn't meet the requirements for carrier-grade video streaming," said Lior Weiss, vice president of marketing for Celeno.

Celeno is formally rolling the chip out at the IBC conference in Amsterdam where it will appear in at least two prototype designs—a set-top box and a gateway. Cisco Systems will include those devices in a demonstration of video home networking for an IPTV service.

Cisco is one of several investors in Celeno along with three venture capital firms and private investors. The company, formed in 2005, has taken $30 million in capital to date.

Celeno has three design wins for IPTV and retail products yet to be announced. The chip will be in production in October at costs "in the high teens," about a 25 to 50 percent premium over competing Wi-Fi chips, said Weiss.

"Wi-Fi today is the de-facto home networking technology for best-effort computer networking applications in over 70 million households worldwide," said Gilad Rozen, chief executive of Celeno, in a press statement. "Celeno's Wi-Fi solution will help to enable the next evolution of wireless video home networking, an application predicted to be deployed in over 150 million households in 2011," he said.