|
Home
Ultrawideband players
get wired for home nets
June 12, 2006
SAN JOSE, Calif. — The WiMedia Alliance has set up
a group to explore whether it should draft a standard for ultrawideband networking over coax. News of the effort comes as
WiMedia member Tzero Technologies announces a UWB chip set that supports both coax and wireless transmission at data rates
up to 300 Mbits/second.
Both moves follow in the footsteps of Pulse~Link Inc. (Carlsbad, Calif.) which is poised
to ship this fall a UWB chip set based on its proprietary technology for both coax and wireless capable of application-level
data rates up to 430Mbits/second.
The efforts amount to a recognition that tomorrow's home networks will be
a mix of wired and wireless options and chip makers need both to get design wins, especially in set-top boxes. They may also
be motivated by a desire to find new homes for UWB technology beyond the wireless USB links promoted by Intel that could become
an instant commodity once they overcome price and performance issues [[refer Clendenin UWB story]].
Responding
to the challenge of the fast UWB chips, competitor Entropic Communications (San Diego) will roll out later this month software
to ratchet up the data rate of its coax networking chips from 135 to 180 Mbits/second. Entropic is also adding new quality-of-service
features to its silicon beyond the features laid down by the Multimedia over Coax Alliance (MoCA) standard it follows.
The Entropic chips are still far behind UWB data rates, typically in excess of 300 Mbits/s. However, Entropic claims
its extensive field tests show its data rates can be reached reliably in 97 percent of North American homes.
"Cable
providers want application-level data rates of 200 Mbits/s, and then they want to move to 400 Mbits/s, but there's no
road map for that on MoCA," said Dan Karr, vice president of sales and marketing for TZero (Sunnyvale, Calif.).
Although the MoCA group hasn't announced a road map beyond its current 135 Mbits/s spec, it claims it passes muster
in the evaluations of cable TV service providers. In a tacit statement of support, a senior executive from Comcast Corp. was
named president of MoCA in May.
"We have met the operator's current requirements and are working with
them on their next generation needs," said John Graham, vice president of marketing for Entropic, currently the only
company shipping MoCA chips.
"When push comes to shove operators don't want to know so much how fast does
it goes as much as what percentage of homes does it work in," said Graham. "Based on field trials, users can get
our maximum data rates on 97 percent of the S connectors in typical US homes. UWB hasn't done extensive field trials like
this," he added.
Entropic is also adding so-called parameterized QoS to its chips, so operators can ensure
delivery of their premium broadcast video throughout the home. "This allows operators to lock up priorities and guarantee
services, so a Windows PC on the network doesn't take down your TV service," said Graham.
The MoCA and
UWB approaches are dueling for sockets in next-generation set-top boxes and their optional peripherals. Those systems bought
by cable and IPTV operators in the millions are increasingly seen as prime territory for gaining traction in tomorrow's
home nets.
"TV service providers are trying to use whole-home digital video recording as a killer app to lock
in customers," said Karr of Tzero. To deliver that app "everyone has pretty much given up on whole home networking
wirelessly, so you have to support a mix of wired and wireless links," he said.
Setting a standard
It remains to be seen whether more UWB backers will attempt to jump into the set-top
fray or define their own standard for coax.
WiMedia's coax study group was announced privately to members a
few weeks ago at the last general meeting of the alliance. If the study group recommends setting a coax standard it will also
propose a general architecture for a separate technical group to flesh out into a standard.
The study group has
no fixed deadline to finish its work. However, "the participants are well motivated and a quick response is anticipated,"
said a WiMedia spokeswoman.
The alliance has nearly 200 members including consumer, computer and chip companies.
Althouh Pulse~Link and Tzero will have an edge in time-to-market, a combined coax and wireless approach will likely
be less than optimal, said, Alun Roberts, a vice president of marketing for WiQuest (Allen, Texas), another UWB chip startup.
Wireless chips generally need the smallest power consumption and die size possible, criteria that are much less important
for makers of wired set-top boxes, he added.
For startups such as Pulse~Link and Tzero a combined wireless and
coax chip may be a matter of expediency, given the costs of developing separate chip sets, especially for still emerging markets
where sales volumes are dicey.
Pulse~Link started the move to a single chip set that uses a UWB physical layer
to drive networking across wired and wireless nets for whole home coverage. Pulse~Link's CWave will deliver application-layer
data rates up to 430 Mbits/s at average power consumption of 2W or less when it hits production in the fall, said Bruce Watkins,
Pulse~Link's president.
CWave already sports parameterized QoS, but that alone is not enough to guarantee delivery
of isochronous data, said Watkins. "The CWave chipset uses the IEEE802.15.3b TDMA media access controller designed from
the ground up to support deterministic quality of service." he added.
Watkins said he expects other UWB companies
part of the WiMedia Alliance group to follow Tzero's lead supporting coax. However, he said the WiMedia specification
would have to be re-written to include changes to both baseband and RF chips needed to handle coax. In addition, he suggested
Pulse~Link may seek royalties from anyone fielding UWB-over-coax products.
"The existing WiMedia wireless
UWB standard as written is not capable of actually providing a robust over-coax technology for real-world scenarios,"
said Watkins. "We believe any alternate UWB-over-coax initiative warrants a thorough understanding of the implications
of our issued and pending patent application portfolio," he added.
Tzero claims its 7200 chip set can deliver
at the application layer data rates beyond 300 Mbits/s for distances of at least 150 meters. The chips support Internet Protocol,
1394 and Tzero proprietary protocols.
"Initially design wins will be in dongles that come off the 14394 port
on a set-top box and bridge to IP," said Karr.
To optimize the chip for use in set-top boxes, Tzero added
two parallel and two serial transport streaming interfaces to link to H.264 compression chips. It also added a generic host
CPU bus similar to the one defined by Analog Devices Inc. for its JPEG 2000 chips.
The resulting 130nm baseband
chip is measures 19x19mm, about half the size of the previous generation. Combined with a companion 180nm CMOS RF chip, the
Tzero 7200 consumes an average 2.5W.
Source: EETimes.com
 |
|
