MANHASSET, N.Y. ( ChipWire) Just in time for the IEEE 802 plenary meetingon wireless LAN standards in La Jolla, Calif., this week, Radiata
Communications has announced it will roll out an 802.11a-compliant,
all-CMOS radio and modem chip set by year's end. The chip set will
enable a 5-GHz wireless PC card with costs on a par with 802.11b
devices but with at least five times the throughput and in a
much cleaner band, the company said.
If Radiata, of San Jose, can deliver on its promise, many issues
on the agenda in La Jolla will be called into question, particularly
those involving the high-data-rate 802.11b standard (for data
transmission beyond 11 megabits per second) and the coexistence of the
various wireless standards in the crowded 2.4-GHz band. But those
issues represent only the tip of the iceberg that engineers will
grapple with at the meeting, which will run through Thursday.
Those attending will hear arguments for harmonizing the HiperLAN2 and
802.11a MAC standard of the European Telecommunications Standards
Institute's Broadband Radio Access Networks, and will vote on
proposals to implement essential quality-of-service (QoS) protocols
for wireless LANs (WLANs). QoS has moved to the fore of 802.11
concerns with the arrival of voice into what was essentially a
The drive for end-to-end QoS is being spearheaded by companies such
as AT&T, Sprint and Verizon, which are looking to push video, audio
and data down the same pipe, making deterministic latency, packet
classification and security essential.
Work on wireless LAN standards will share the spotlight with efforts
on personal-area networks. Proposals will be heard for both
low-bit-rate versions, in the realm of 20 kbits/sec., and medium- to
high-bit-rate implementations that will equal and surpass current,
next-generation 10-Mbit Bluetooth work by jumping right to 20
Riding a rising curve of interest, the 802 wireless working groups
will attract most of the 700-plus attendees expected at the meeting
and the interest is well-founded. The market for wireless
networking in the enterprise alone will rise from $771 million in
1999 to nearly $2.2 billion by 2004, according to estimates by
Cahners In-Stat Group, in Newton, Mass.
Such growth prompted Radiata's development of its latest chip set.
Using 0.18-micron CMOS technology, the set will allow for a wireless
PC-card-based bill of materials of roughly $150 by year's end. Chris
Fisher, vice president of sales and marketing at Radiata, said the
chip set will have two effects.
"First, it will dispel the notion that 54-Mbit/sec. wireless networking
is one to two years away," he said. "Second, our use of all-CMOS
technology over more exotic alternatives such as BiCMOS, SiGe or GaAs
will ensure a cost-entry point on par with today's 802.11-based
Radiata is not alone in its drive to 5 GHz. Atheros Communications
Inc. made related announcements but did not disclose details. Philips
Semiconductors is also working on a BiCMOS front-end solution for
A number of factors mainly higher data rates and a cleaner
spectrum is spurring the drive to 5 GHz, which is becoming
increasingly attractive as applications grow more demanding and the
2.4-GHz band gets crowded.
These points are high on the agenda for the 802 plenary meeting this
week. The group will hear proposals to increase the data rate of
802.11b from 11 Mbits/sec. to 22 Mbits/sec. and higher from
companies like Alantro Communications Inc. Alantro was recently
bought by Texas Instruments Inc., which could help Alantro's push for
standards based around its technology.
With TI's backing, Alantro may stand a better chance against
proposals from 3Com Corp., which will push 40-Mbit technology, and
Sharp Electronics Corp., which will also enter the fray.
Regardless of the proposal, the obstacles to acceptance lie not in
technical issues but in regulatory ones. Al Petrick, vice chairman of
the 802.11 Working Group, said the technical elements are fairly
straightforward. Determined by basic physics, they boil down to a
trade-off between distance and data rate.
"Right now, we're looking to set some basic criteria on
signal-to-noise over a given range, multipath-handling capability,
throughput, backward compatibility, fallback, complexity and the use
of the existing MAC layer," said Petrick. "However, FCC requirements
will be a major factor."
With the arrival of voice in the data-centric network, those
attending the meeting now bear the burden of deciding on a QoS
methodology for a number of reasons. The problem starts with the
higher layers, those above the MAC, assuming incorrectly that a LAN
rarely loses or delays packets.
In fact, WLAN-PHY error rates are
three orders of magnitude greater than those of wired LANs. As a
result, unlike other 802 LANs, 802.11 retransmits unacknowledged
frames. In addition, retries cause unpredictable delays that often
block the transmission of subsequent, queued frames. Wireless links
also incur high per-packet MAC and PHY overhead 802.11b
framing, gaps and acknowledge add up to 32.6% (vs. 3.2%