Scramble to nail down the home network continues

Scramble to nail down the home network continues
SAN JOSE, Calif.—The 802.11b wireless networking format is gaining acceptance in the consumer market, but some vendors in the home gateway space, hoping to expand the home networking market, are already saying it isn't powerful enough to meet the demands of an converged data and entertainment network.

Indeed, several companies are already looking beyond current options to higher speed alternatives, including both wired and wireless technologies, but all of them come with tradeoffs.

"If you just want to share Internet access from room to room, then about 5 Mbits/second is enough bandwidth to satisfy a consumer," said Scott Smyers, vice president of Sony Electronics Inc.'s interconnect architecture division (San Jose). "But it you want to distribute video content, then 10 Mbit/second guaranteed bandwidth is about the minimum, so 10 base T Ethernet isn't enough, and neither is 802.11b. That's just the basic cost of entry to distribute video from room to room."

Smyers spoke as part of a panel on home gateway technologies at the Communications Design Conference here. Several executives agreed that the long-term vision for the home market is based on having some type of home gateway system act as a content router, distributing video and audio services, voice telephony, Internet access and other data services.

Alex Vasilevsky, chief technologist for home gateway software vendor Ucentric LLC (Maynard, Mass.), pointed out that the average U.S. home has 2.8 television sets, and that a digital video stream requires about 6 Mbits/second of bandwidth. So, just to support TV services, a home network needs to offer approximately 18 Mbits/second.

This, by far, exceeds the 11 Mbits/second limitations of 802.11b, and some executives are taking a serious look at its faster cousin, 802.11a, which offers 54 Mbits/second. "We think that 802.11a shows a lot of promise," said Smyers.

Compatibility issues
However, that format transmits data in the 5 GHz range, while the 802.11b format uses the 2.4 GHz band, making them incompatible. "I have never seen a technology supplant its predecessor without being backwards compatible," pointed out Pat Romano, vice president of engineering for 2Wire Inc. (San Jose), a supplier of gateway systems that sells primarily to service providers. He suggested that 802.11a systems would need to include chips for both formats, although that would drive up costs.

2Wire also support the HomePNA format, which uses telephone wiring within the home to link various systems into a network. The company is currently producing chips for the 2.0 specification, and Romano said they will soon be able to offer chips that deliver bandwidth up to 40 Mbits/second. A new 3.0 spec for phoneline networking is due within a year, and the goal is to deliver bandwidth as high as 100 Mbits/second.

All of the executives agreed that any home network must avoid requiring new wiring, which rules out standard Ethernet, and other formats such as 1394, despite any advantages they bring such as bandwidth and ease-of-use. In fact, most industry players seem to prefer wireless formats, despite their limitations, such as range or cost.

The segment has already watched wireless format HomeRF come and go, exiting the space because it couldn't hold its own against the rapid deployment of the 802.11 variants. Another alternative that is just emerging is 802.11g, which offers that same bandwidth as 802.11a, but transmits on the same 2.4 GHz band as 802.11b. In other words, it would be compatible with the current dominant version, but offer more bandwidth.

The only wrinkle with this format is that it has not yet been approved as a standard. Paul Chiuchiolo, systems engineer for WLAN products at Intersil Corp. (Palm Bay, Fla.), said out of four original proposals for a higher bandwidth wireless networking format on the 2.4 GHz band, only one proposal is still in consideration, the one developed by his company. The IEEE working group is expected to vote on adopting that format as a standard sometime next month, and while Chiuchiolo said he expects it to be approved, there is doubt elsewhere in the industry.

Will Strauss, president of market research company Forward Concepts (Tempe, Ariz.), argued that the proposal won't see the light of day. Texas Instruments Inc. is also part of that group, while its own proposal has been eliminated from consideration, Strauss said TI controls enough votes to block approval of any other architecture.

Strauss said that current home networking technologies likely will be adequate for some time, because it doesn't do much good to offer 10 Mbits of internal bandwidth, when the link to the outside world, either through digital subscriber lines or cable modems, is slower than that. "Right now, nobody can afford to have 10 or 20 Mbits/second delivered to the home," he said. "The infrastructure to offer that kind of bandwidth will not be available still for another 10 years," he predicted.

However, there is another concept that found some approval. Sony's Smyers said that homes could have several different home gateways, each for different purposes. For example, one could be used for on-line gaming, while another delivers entertainment content such as TV signals and music, while a third design could be dedicated to data services, especially Internet surfing. This could increase the bandwidth in the home by having multiple data lines arriving at the front door.

"You can't make a single gateway that does everything," he said. "Otherwise it becomes like a bloated Swiss Army knife."