The idea of home entertainment networking using 802.11 wireless LAN
technology sounds great. It might even be great — once it arrives.
You could watch Sex In The City on one TV while the kids watch a second
program piped in over the same satellite or cable service in another room —
transmitted from the home media center or digital gateway via a Wi-Fi WLAN.
You could network PCs and stereo system and stream MP3s stored on PC hard drives
to your stereo speakers, or record multiple HDTV programs coming over the satellite
service on hard-disk-based PVRs (personal video recorders) in different rooms.
Some WLAN chipset vendors are even suggesting you could stream TV signals over
a WLAN from a gateway to a Wi-Fi-equipped PDA or tablet PC. You could set up
wireless security cameras and motion sensors outside and stream video back to
a PC or TV.
The possibilities and permutations are endless, and with Wi-Fi, you avoid expensive
and disruptive cable installations — which is all great.
But as we saw last
time, some analysts believe it will be a few years at least before Wi-Fi
home entertainment networks become a mass market proposition — even though
the first cable/satellite set-top boxes with wireless capabilities have already
begun to appear, and even though virtually all set-top box and consumer electronics
manufacturers have prototypes and many are pilot testing them.
So what’s the hold up?
There are a couple. For starters, WLAN technology itself is really not ready
for home entertainment networking yet. Raw bandwidth is the issue.
WLAN chipset maker Intersil of Irvine, CA, says consumer electronics
manufacturers like Sharp, Sony and Panasonic are saying they need 30Mbps of
bandwidth for home entertainment networking to work the way they think it should.
"We asked, ‘What the heck do you want that for?’" says Intersil vice
president of marketing Chris Henningsen. "They want enough for three channels
of CD-quality audio at 1.5Mbps per channel, three of DVD-quality video at 5
to 8Mbps, a couple of Internet browser channels and a couple of 802.11 phone
channels. It got up to 30Mbps pretty quickly."
Even allowing for network overhead, 802.11a easily provides all the bandwidth
needed. Indeed, WLAN chipset makers specializing in home entertainment networking
(firms like Magis Networks of San Diego, CA, and
ViXS Systems of Austin, TX) already have
802.11a-based products ready for market.
Raw bandwidth alone isn’t enough, though. You need some way of establishing
priorities for traffic on the network so that time-sensitive data like video
isn’t disrupted when some applications hog bandwidth, or when bandwidth between
two nodes dips due to propagation issues.
If all you’re doing is moving big data files around or browsing the Internet,
network congestion on a home LAN isn’t that critical. It just takes a little
longer for the page to display, the job to print or the file to transfer.
If you’re sending an HDTV stream over the home LAN, though, and there isn’t
enough bandwidth available to relay it from one room to another at the same
rate it’s coming in from the satellite service or being streamed from the networked
DVD player, video and audio quality can seriously degrade.
Equipment vendors understand that consumers will not accept this kind of performance
degradation. Instead they’ll wait until the technology can guarantee it doesn’t
happen.
Establishing Quality of Service (QoS) guarantees for time-sensitive applications
involves including a priority rating in the header of each IP packet — higher
priority for audio, video and gaming, lower priority for data — and monitoring
and controlling traffic to ensure high-priority packets go through first when
bandwidth is at a premium.
Wi-Fi currently does not incorporate any QoS mechanism sufficient to ensure
unimpaired audio and video quality. However, a task group of the IEEE (Institute
of Electrical and Electronics Engineers) 802.11 committee is currently working
on a QoS fix referred to as 802.11e.
The fix involves refining the 802.11 MAC (Media Access Control) layer. The
802.11e group is expected to finalize the new standard by the end of 2002. The
first products will likely be available by mid-2003.
The 802.11e protocol will be common to all 802.11 networks — a, b, g — and
it will be backwards compatible with existing 802.11 WLANs. Users and vendors
will supposedly be able to bring existing 802.11 access points up to 802.11e
compliance with a simple firmware upgrade for many products.
That may be a reasonable way to proceed in the world of PCs and networking,
but consumer electronics and set-top box manufacturers, who are expected to
drive the market for home entertainment networking, will likely balk at making
a commitment to unfinished technology
"You can’t have a new standard come out every year and expect consumer
electronics manufacturers to jump on board each time," says Michael Greeson,
senior analyst and director of broadband research at Dallas-based market research
and consulting firm Parks Associates.
"It’s only when the ratification [of 802.11e] is done, only when you have
a package of workable standards that the consumer electronics manufacturers
will be willing to get behind it."
There is an alternative to waiting. Companies like Magis and ViXS have developed
proprietary QoS technologies that work with 802.11a — that are possibly superior
to 802.11e, in fact. However, this means that network equipment built using
their partly proprietary chipsets will not be 100-percent compatible with mainstream
Wi-Fi products.
This may or may not be an impediment to growing the home entertainment networking
market, but Greeson makes it clear that at least some equipment makers, perhaps
a majority, will wait for standards.
The technology problems don’t end there, according to Intersil. It believes
that rivals like Magis and ViXS are making a mistake going ahead with 802.11a
technology rather than waiting for 11g.
802.11a has clear advantages in some applications — public access in an airport,
for example — because it supports more non-interfering radio channels, says
Jim Zyren, director of strategic marketing in Intersil’s Prism wireless unit.
The fact that 802.11a, which operates in the 5.8 GHz U-NII band, has shorter
range, however, makes it a questionable choice for home entertainment networking,
where customers will expect to have one access point covering the entire house.
Even in medium-size homes, 802.11a may not go far enough, Zyren suggests.
"A lot of [equipment manufacturing] companies believe they’ll need the
reach and wall-penetrating power of 11g at 2.4 GHz — which can also provide
the same data rates as 11a," he says. "That’s why we’re optimistic
that 11g will be very important in this space."
If 802.11g does turn out to be the protocol of choice for wireless home entertainment
networking, that puts the date for availability of equipment with mass market
appeal even further out. The 11g protocol has not been ratified yet, and it’s
not clear when it will be.
Whatever the technological hold-backs, another group of players — cable and
satellite service providers — aren’t all that interested in wireless right
now anyway, Greeson says. According to many scenarios, having them along will
be crucial to promoting the idea of home entertainment networking.
"We just did a series of interviews with [service providers] and set-top
manufacturers," says Greeson. "They’re telling us that [home entertainment
networking] is not real now and won’t be for several years."
Some set-top box manufacturers are also worried that consumers will balk at
installing the kind of one-box-does-all device — a combination digital decoder,
PVR, wireless access point and even voice over WLAN bridge — that some have
envisioned.
If the device goes down, too many services would go with it.
Is this pessimism — or just realism? Next time we’ll hear a more optimistic
outlook from the leading wireless home entertainment networking chipset maker,
Magis Networks of San Diego.
