The home network, joining a diversity of electrical appliances and systems, will necessarily be a multimedia solution. In recent months a number of networking technologies have been aimed at the home marketplace, each offering specific strengths as well as specific limitations. Purely wireless solutions will allow for untethered device control and content movement, but are too expensive, even with the economies of scale offered by recent industry consortia. Phone line networking offers synergies with high bandwidth Internet access and can be affordably implemented, but is limited by the number of available phone jacks. Traditional wiring schemes are feasible for new homes, but do not suit the homeowner’s need for a modular, cosmetic networking solution. The power line is unique in enabling low-cost, high performance networks between electrical appliances and in extending the functionality of other home networking media. As the common denominator of residential electrical appliances, the power line is the natural pipeline for the digital information flows of networked home.

Market Macros: Creating a Need for Residential Interoperability

Multiple PC Homes

The rise of the home network can be attributed to several simultaneous market trends. Receiving the lion’s share of industry attention has been the phenomenon of the multiple PC home. Approximately 14 million homes had more than one personal computer by year-end 1997, amounting to roughly 35% of the 40 million American homes with PCs. These numbers are expected to rise dramatically, reaching 35 million multiple PC homes by 2000, totaling 61% of the anticipated 57 million computer-enabled US residences.

These statistics drive industry pundits to conclude that PC-PC connectivity will dramatically rise in importance as multiple PC homes proliferate. This conventional wisdom dictates that homes will follow the behavior of business in moving from closed end computer terminals to networked architectures. While statistics about two-PC prevalence in and of themselves don’t necessarily point to a home network, they do indicate that the home space needs multiple computers for multiple tasks and users.

"Content Overlap"

Content Access in the On-Line Home:

The rise of the on-line home and the proliferation of Internet-capable devices are additional phenomena creating a need for home networks. It is estimated that 47% of US households will have some type of Internet capable device (PC, screen phone, etc.) by 2002. The home network will rise in importance in the on-line home because it will: 1) allow for the organization of content from numerous Internet capable devices and its delivery to where the family needs it; 2) allow for shared Internet access, thus reducing the costs associated with going on-line; and 3) increase the amount of digital content in the home, thus heightening "content overlap".

The proliferation of Internet capable devices in the home will create an information management nightmare. With multiple PCs, screen phones, set-top boxes, and even white goods downloading content, the residents of the on-line home will need to search for information among multiple devices. Sales of Net appliances, which reached 1.4 million units in 1997 will reach 42 million units in 2002- not far behind projected PC sales of 56 million units in that year.

The information management problem created by multiple Internet-capable devices in the office space is a telling example for the future of the on-line home. Workers who have both a desktop and a laptop PC waste time transferring updated information between devices, and often misplace emails and other content. This inefficiency has caused IS managers to reduce the number of PCs per worker, often assigning a laptop for office, road and home use. The opposite trend will occur in the home space, wreaking havoc. Content will reside in a number of devices around the home, and without the home network, will remain unorganized and out of reach of residents. Where is that recipe that I downloaded yesterday? On my PC? My TV? My screen phone? My Internet-capable microwave? Did I update my calendar and phone book on my laptop, or my PDA, or the kid’s PC? The home network allows information received form multiple points around the home to be aggregated, organized and distributed to the resident where and when they need it. This capability will become crucial as points of Internet access and the amount of content increases in the on-line home.

Home networks will also allow for shared Internet access, thus reducing costs. Shared Internet access reduces the costs associated with going on-line, by allowing the whole family to surf the net through one account and one phone line. Networked Internet access will take on heighten importance as xDSL, cable and satellite modems increase residential bandwidth, and the allow homes to stay continuously connected to the Internet.

The Multimedia Network: An Introduction to Radio Frequency, Phone Line and Power Line Solutions

Radio Frequency

A number of digital wireless solutions have recently addressed the residential space. The HomeRF working group, a consortium of leading consumer electronics and PC-centric companies, seeks to bring about "a broad range of interoperable consumer devices by establishing open industry specifications for unlicensed RF digital communications between PCs and CE devices anywhere in and around the home."

The HomeRF solution will be implemented through an interoperability protocol termed the Shared Wireless Access Protocol (SWAP), set for release in Fall, 1998. Similar to IEEE 802.11, SWAP chips will transmit in the 2.4 GHz ISM band, at up to 2Mbps. Once in silicon, this wireless interoperability standard will allow for shared, mobile voice and data communications from any point in the home. The HomeRF working group is targeting SWAP at wireless Internet, file and peripheral sharing, PBX and call routing applications, and mobile device control in the home space. SWAP chip sets will most likely be available in 1999 from a variety of suppliers and it is rumored that their bill of material costs at introduction will be in the $30 range.

Another wireless residential networking solution will be offered by Sharewave, a start-up from Eldorado Hills, CA. Sharewave proposes a network architecture with the PC as so called "information furnace". According to Sharewave’s vision, the PC will act as "…an information furnace that centrally aggregates, manages, and distributes computing power and digital information throughout the household."⁵

To implement this vision, Sharewave has introduced a proprietary compression technology called NAMI™ (Network Adaptive Multimedia Image Compression), to be implemented as an ASIC solution. NAMI compression enables transmission of real time video, and computer graphics, from the PC to the TV and a number of other consumer electronics in the home. NAMI compression allows for the transfer of digital content at speeds up to 4Mbps. Set for release in 1998, pricing for Sharewave’s NAMI chip sets has not yet been published.

Just as HomeRF is attempting to introduce a de facto standard in wireless residential networking, the Home Phoneline Networking Alliance is attempting to make its scalable home networking solution widely available. HomePNA endorses two compatible technologies- the initially available 1Mbps technology of Tut Systems and Epigram’s 10Mbps solution – and will soon make a joint specification and marketing effort.

Tut’s 1Mbps technology implements a CSMA/CD protocol and transmits in the 5.5Mhz-9.5Mhz frequency range. Tut will begin shipping its HomeRun family of products in Q3 ‘98. These products essentially use an Ethernet MAC (media-access controller) with a phone-line physical layer. HomeRun is targeted for high reliability in networks with up to 500ft of wiring between any two nodes. The HomeRun transmission is frequency-isolated from the analog phone voiceband, so the wiring can simultaneously support voice and data. Tut claims its technology will also coexist with xDSL links into the home via phone wires. Tut will offer HomeRun network- interface cards, ICs that integrate an Ethernet MAC with a HomeRun physical layer, and stand-alone physical layers that work with other Ethernet MAC ICs. The network-interface cards are price targeted at $140 and Tut claims that PC companies will be able to implement the same technology in these for less than $50 and ultimately see the price approaching $10.

HomePNA’s next generation technology is brought by Epigram’s patent-pending 10Mbps technology. Epigram’s Home Ethernet uses sections if the 2-30MHz frequency range, and is intended to scale up to 100Mbps. Epigram’s Home Ethernet gains its robustness from a highly flexible rate adaptivity to the changing electrical characteristics of the phoneline communications channel.

Power Line

Power line carrier has traditionally been known only as a control medium and has earned a reputation of questionable reliability. In recent years, several more robust power line control chips have come to market, but at extremely high price points. Currently, with market trends giving birth to the networked home, several new device control and network chips are utilizing the power line for high performance at a low cost. These new solutions will solidify the role of the power line medium as the most versatile and highest value communications channel of the networked home.

Power Line in Home Automation: Need for Robust, Medium-Speed, Interoperable Solutions

"Home Automation" in its minimal sense can be understood as control of residential devices from remote locations. In the context of the networked home, however, home automation should be defined as centralized control of appliances, information gathering about their behavior, and their remote configuration. Extending this definition, it is accurate to define a "control+" sub-section of home automation, which describes more throughput intensive residential applications, such as voice-based control and communication between points on the home LAN.

In the device control space, power line communications were first introduced and implemented in the late 1970s. Since this time, traditional solutions such as X-10 (60bit/sec), have created a growing market for simple appliance control, but have been severely limited by their scalability. Such control solutions are acceptable for so called "On, Off and Dim", functionality, but send unacknowledged packets, and can fail in high-interference environments.

Notwithstanding the technological limitations of X-10, it works, is easy to implement and it has a respectable installed base. The early adapters and TAFs at whom large OEMs will target their initial home networking products use and generally support X-10. The currently large and growing channel for so called "wireless" home automation devices- from Radio Shack to Sears to Home Depot to a number of mail order catalogues- is full of X-10 power line devices. For these reasons X-10 will certainly be included in the multimedia home network solution, and there is a clear need for all other communications chips on the power line to co-exist with X-10 signaling. ITRAN Communications Ltd.’s IT5000, IT800 and ITM1 components are all co-existent with X-10 signaling

The only truly open home automation standard available today is the Consumer Electronics Bus (CEBus). Traditional CEBusŪ is an excellent interoperability standard, but suffers from limited bit rate and inter-phase communications difficulties. At 6.6kbps, traditional CEBus modems can impede performance in multi-node systems, such as whole-house lighting solutions. Today’s sophisticated Home Automation systems integrate lighting, simple-appliance control and some HVAC applications over residential power lines. Traditional CEBus is also unable to scale up to "control-plus applications", such as voice based control, baby monitors and intercoms. For PLC home automation chips to offer control-plus applications, they need bit rates in the 50kbps range. ITRAN Communications Ltd. will introduce it 50kbps, CEBus compatible modem, the IT5000, in Q4 ’98.

Power Line for Home Networking: Need for 1.5Mbps+, Robust, Scalable Solutions

In contrast to Home Automation, "Home Networking" can be understood as the movement of data (either originating in the home, or from an external WAN) between residential PCs, peripherals and consumer electronics. Current home networking target applications include file sharing between PCs, printer sharing, shared Internet access and networked gaming.

In order for any of the individual home networking technologies discussed above to be successful, they must offer a minimum of 1Mbps bandwidth, a high degree of robustness, low cost, and seamless, easy implementation.

No currently available power line technology meets these criteria, although several high performance AC modems and applications will enter the market in early 1999. Intelogis Inc., of American Fork, Utah, is currently offering a $249 package of electrical out-let adapters that network two computers and a printer. Transmitting at 350kbps, these PASSPORT™ adapters certainly represent a step on the correct path to the networked home. They are a functional vanguard of things to come on the power line, but at 350kbps lack the throughput to scale up the coming needs of the networked home.

For the power line to assume its role as the natural pipeline for the digital information flows of networked home, power line modems must deliver 1.5Mbps speeds with high robustness at a low price point. The necessity of these criteria is twofold: 1) 1.5Mbps is the minimum workable bit rate for transmitting acceptable qualities of compressed video and for connectivity to USB. 2) 1.5Mbps power line modems will allow the AC wiring to be used as a bridge between other home networking media (phone line and RF), without a significant down in bit rate. ITRAN Communications Ltd. will be introducing its 1.5Mbps power line modem, the ITM1, in Q2 1999.

The role of power line communications in the home network is as an omnipresent device control and high speed networking avenue. Power line device control modems, if robust enough to overcome the strong interference of the medium, offer excellent value through low silicon costs. Power line networking modems, if able to deliver 1.5Mbps bit rates and high robustness, offer significant cost advantages over phone line and RF media, and can be accessed through every power outlet in the home. Omnipresent access also makes the power line an excellent network bridge for RF, IR and phone line networking. It is this high performance- in cost, speed, robustness and ease of implementation- that makes the power line the natural pipeline for the digital information flows of networked home.