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Hammering out Standards

Sat, 09/30/2000 - 8:00pm
David Iler, Contributing Editor

The home networking standards sector is rife with activity, as several standards groups vie to firm up their individual specifications, evolve existing specs and create new ones. Driven by stratospheric marketing projections and escalating speed and feature requirements, standards groups are staking out technical ground before the expected mass market, and operators looking to support the standards, try to sort out the meaningful differences and synergies in each.

It won't be easy.

There are at least eight major standards efforts, initiatives and groups—most prominently in the wireline camp, including the Home Phoneline Network Alliance (HomePNA) and the emerging HomePlug Powerline Alliance; and in the more crowded and contentious wireless camp, with HomeRF Working Group, Bluetooth and wireless Ethernet.

Seeking to tie together entertainment systems on a common platform is the Home Audio Video Interoperability (HAVi) group, while the newly-formed Open Services Gateway Initiative (OSGi) is taking a big-picture view of home net architecture by addressing multiple services, wide area networks and local area networks and devices.

Also deeply involved with home net standards is the Consumer Electronics Association, which recently reorganized its far-flung efforts in a complex quest for compatibility between all standards and devices—devices which include everything from dimmer switches and thermostats to appliances and home theater systems.

The air war

Sparked by a recent U.S. Federal Communications Commission ruling that essentially breathed life into the HomeRF Shared Wireless Access Protocol (SWAP) specification, the wireless home net space is much more lively. HomeRF is a much-maligned spec, disparaged by both wireless Ethernet—802.11b—and Bluetooth proponents.

On August 31, the FCC amended its rules to allow frequency-hopping spread spectrum transmitters operating in the 2.4 Gigahertz (GHz) band to use a minimum of 15 hopping channels spanning a total of 75 MHz. This will allow for hopping channels up to 5 MHz wide, allowing for higher data rates.

The move effectively allows HomeRF to boost its data rates from approximately 1.6 Megabits per second (Mbps) to 10 Mbps, putting it on par with data rates supported by 802.11b.

The ruling "assures us a future," says Denis Kehlmann, HomeRF Working Group member and senior manager of Siemens Digital Products. With the boost in data rates, "We will be able to support all kinds of new applications," says Kehlmann, who adds, "we expect additional support from new people coming into the working group."

The Commission's action was initiated by a request by the HomeRF Working Group to use bandwidths up to 5 MHz. In a detailed "First Report and Order," the FCC addressed objections raised by the Wireless Ethernet Compatibility Alliance and several other entities, including Lucent Technologies, Intersil Corp. and Silicon Wave Inc., which makes chips for Bluetooth devices.

The Commission rejected comments that widening the band for frequency hopping would result in interference of other devices using the 2.4 GHz band, including Bluetooth devices, calling such fears "greatly overstated."

Kevin Duffy, director of business development and product management for Siemens Digital Products, points out that the HomeRF spec, in addition to enabling data transmissions, supports the Digital Enhanced Cordless Telecommunications (DECT) standard and can execute up to eight active voice calls simultaneously.

i_102xfig1.gif
Figure1: HomeRF adapts the super-frame length to minimize latency from one isochronous period to the next.

Duffy notes that a future version of the spec, SWAP 2.0, is being developed with input from Dolby Laboratories Inc. to define a streaming media component. Other aspects of the new iteration will include boosting the data rate to 10 Mbps, and roaming. Duffy expects version 2.0 of SWAP to be released later this year. A possible migration to the 5 GHz band may be the subject of future SWAP versions.

The current version of Bluetooth, according to David Etheridge, director of product marketing for Ericsson's home communications group, has been adopted by the Institute of Electrical and Electronic Engineers Inc. as its 802.15.1 personal area network (PAN) standard. Within the standard, Etheridge says there are short range (10 meters) and long range (100 meter) specifications. Ericsson, he adds, has developed technology to extend the range beyond those specifications, up to 300 meters.

Work is underway on 802.15.2, which Etheridge says will make Bluetooth and 802.11 compatible and possibly interoperable. "At the very least," says Etheridge, the effort "will make them co-exist." Further down the road, 802.15.3 is slated for data rates up to 20 Mbps.

A companion spec to Bluetooth, HomeLAN 2, works in the 5 GHz band, is capable of 54 Mbps, and is about a year or two away.

Powerline standard powers up

Long recognized as a viable medium for home networking, home powerline proponents, formed as the HomePlug Powerline Alliance, decided on a baseline technology from Intellon for its specification in May. According to HomePlug President Alberto Mantovani, the group will be conducting a field trial later this month or early next (November) involving 500 "friendly" homes as a proof-of-concept. The trial will be used to determine how to implement security and to improve the Media Access Control performance of the protocol, particularly for multimedia.

The feature set of the spec, which is targeted to be complete in December, will include a (theoretical) 10 Mbps Ethernet-class data rate to support gaming, multimedia and voice-over-IP. Mantovani says the modulation will be based on Orthogonal Frequency Division Multiplexing (OFDM), and HomePlug transmissions will run between 4 and 21 MHz.

A competing technology developed by Inari may make HomePlug's quest for a unified home powerline standard interesting. Inari is not a member of HomePlug, and in August released a hardware developers' beta kit and samples of its powerline silicon.

Inari, formerly Intelogis, uses technology developed by its engineers while part of Novell Inc.'s Embedded Systems Technology division.

Tying the ends together

Recognizing the need to support several standards, the Open Services Gateway Initiative (OSGi) released a specification in May for a "service gateway." The gateway is designed to act as a server that a network operator can control to download and provision home net services.

Application program interfaces (APIs) for the spec, implemented on the gateway and made available to service developers, are based on Java programming language and comprise a service framework, device access service bundle, log service and Java environment. The device access service bundle is geared to Consumer Electronics Bus (CEBus) devices (see below) to create, register and define within the service framework those devices so service applications can use them.

i_102fig2.gif
Figure 2: The OSGi (Open Services Gateway Initiative) API.

For example, a home security system application may be programmed to dim certain lights in the home. John Barr, OSGi president and director of architecture and technology strategy for Motorola's personal networks group, says that the challenge is to link CEBus-type devices to home entertainment networks run by a HAVi application, for example. Thus a "CEBus bundle" of devices and a "HAVi bundle" of devices can be tied together by an application or service and run off a gateway that supports OSGi.

Potentially, says Barr, set-tops and/or cable modems could also be OSGi enabled. The group will also be working on remote management of the gateway and service provisioning by operators and improving security.

Barr is watching implementations of Microsoft Corp.'s Universal Plug and Play, and he notes the group will address "persistent data" issues; for example, allowing a network reconfiguration after the power goes off and on again.

Ambitiously, Barr and OSGi are looking to develop gateway technology to let network operators "continually add services to the home without truck rolls." A 1.1 version of the OSGi spec is due next spring.

Consumer electronics voices

Meanwhile, the Consumer Electronics Association announced in August a reorganization of its standards settings committee—a move reflecting the "changing home networking industry," it says. Over the years, the CEA has developed several home net initiatives and protocols, each of which are now undergoing a review.

"Compatibility is our watchword right now," says Virginia Williams, director of technical standards for CEA. She says the goal of the group in all its efforts is "to enable of all the existing (home networking) technologies to be compatible with each other."

The group's R-7 Home Networking Committee, formed in 1999, will oversee the CEA's integrated home systems and home automation standards committees, which previously worked under specific product categories. "The consensus among participants in the home data networking discovery group was that R-7 should work toward standardizing boundaries between the different home networking systems," said Ralph Justus, CEA vice president of technology and standards, in a press release.

The CEA's home net standards will now be addressed by four groups under R-7. Those are: R-7.1, the Electronics Industries Alliance (EIA) 709 suite of standards (formerly known as HCS-1); R-7.2, CEBus; R-7.3, a Data Networks Subcommittee that has recommended creating a standard for powerline data networking; and R-7.4, a joint Video Electronics Standards Association (VESA)/CEA subcommittee charged with forging version two of the VESA home network specification.

EIA-709 suite

The EIA-709.1 protocol provides for peer-to-peer and master-slave controller-based systems and defines the services supported in layers 2 through 7 of the Open Systems Interconnection (OSI) model for network protocols. EIA-709.1 defines a set of features, including network management, message security authentication and message prioritization, to support basic on/off devices or more complex devices. The protocol can support twisted-pair, power line, radio frequency, infrared, coaxial cable and fiber.

The EIA-709.2, or Control Network Powerline Channel Specification, outlines communication over power lines both inside and outside of homes over 120-volt AC and 240-volt AC wiring. The channel uses the 125 kilohertz (kHz) to 140 kHz band and runs at 5.65 kilobits per second (kbps). "We expect that HomePlug and CEA will start having joint meetings," says Williams.

EIA-709.3 supports "free topology," two-way communication at 78.125 kbps among as many as 128 devices in a single twisted-pair segment, which can be extended through the use of physical layer repeaters.

The R-7.1 group is working on a spec for extended addresses and a standardized set of network plug-in tools. A plug-in in this context is essentially software that creates a profile of the device so it can be recognized on a network.

CEBus

This series of specs (EIA-600) for the Consumer Electronics Bus (CEBus) addresses remote control, status indication, remote instrumentation, energy management, security systems and entertainment device coordination. The R-7.2 subcommittee recently completed a spec that places CEBus' common application language (CAL) on top of XML (Extensible Markup Language) to facilitate compatibility between CEBus and other platforms.

VESA

In August 1999, the Video Electronics Standards Association released draft specifications of version 2 of its home net standard, allowing for the access of home network devices, such as VCRs and security systems, easily and remotely, and setting the framework for a "backbone" to tie all the home networking pieces together. The effort is now under the purview of the CEA.

With the intent of integrating all proposed home net standards, version 2 includes physical media and data link layers using IEEE 1394b, a "long distance" version of IEEE 1394-1995 and a digital backbone for inter-networking. The intent of the backbone, says Williams, is to create peaceful co-existence between technologies.

Endgame

With so many initiatives brewing, home networking advocates are challenged to sort out the countless details involved with interoperability and compatibility issues. For full service home networking and automation to achieve any type of marketability, there are still plenty of bridges to cross within and among each standards group.

E-mail: editor@denver.net

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