If there’s a Wireless Home Networking lesson to learn from the Tower of Babel, it’s that we don’t need (and will never have) one wireless standard for homes, offices, schools, airports, restaurants, grocery stores, bowling alleys, and beauty shops. As intriguing as it may sound, it is not practical or desirable to have one wireless standard for all environments, purposes, and types of devices.

Wireless Tower of Babel

Wayne Caswell

Home Toys Article
Home Toys Article
- August 2001 -
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by Wayne Caswell
HomeRF Marketing Manager, Siemens IC Mobile

 If theres a Wireless Home Networking lesson to learn from the Tower of Babel, its that we dont need (and will never have) one wireless standard for homes, offices, schools, airports, restaurants, grocery stores, bowling alleys, and beauty shops.  As intriguing as it may sound, it is not practical or desirable to have one wireless standard for all environments, purposes, and types of devices.

Just as variety is the spice of life, it also is the focus of this Wireless Home Networking issue of HomeToys.com.  Consider these questions: 

  • Is a PDA better than a PC? 

  • Is a PC better than a TV, or a stereo system, or a mainframe computer?

  • Is a wireless network better than a wired one?

  • Is 5 GHz better than 2.4 GHz or 900 MHz?

  • And, is HomeRF better than Bluetooth, 802.11b, 802.11a, HyperLAN or whatever new protocol comes along later, either proprietary or standards-based? 

As long as theres a good purpose for each, they will all prosper in some way or another.

Can Biblical Lessons have Wireless Implications?

The Bible (in Genesis Chapters 10 and 11) tells a story of the Tower of Babel, where descendants of Noe started building a great city in ancient Babylon.  As one tall structure, it was to reach into the skies and provide a shortcut to heaven, thus bypassing God.  But God punished their vanity and caused the Confusion of Tongues.  As a result, construction stopped and the people dispersed across the land speaking different languages.  

If theres a Wireless Home Networking lesson to learn from the Tower of Babel, its that we dont need (and will never have) one wireless standard for homes, offices, schools, airports, restaurants, grocery stores, bowling alleys, and beauty shops.  As intriguing as it may sound, it is not practical or desirable to have one wireless standard for all environments, purposes, and types of devices, including notebook PCs, handheld PDAs, cordless and mobile phones, baby monitors, garage door openers, security systems, and key fobs.  

Variety will serve us well in home networking just as it has served us in other markets including everyday ground transportation.  While some of us drive economy cars, others drive luxury cars, sports cars, minivans, SUVs, motor homes, buses, pickup trucks, dump trucks, limousines, motorcycles, mopeds, bicycles, or scooters.  And others use roller skates, public transportation, or just walk.

Hyper-Hype and Disparagement Damage

Even though Home networking is still a relatively small market of mostly early adopters, it is growing and has great promise, especially with broadband deployments expected to take us from early adopter to mass-markets.  That large opportunity has brought wireless competition home, and its made worse by economic slowdowns effecting sales of business networks.  Competition has driven prices down, and that is good news for consumers; but it also has caused confusion.  

The wireless home networking market is now flooded with marketing hype.  Many organizations now position their products as the only acceptable solution and even make false or misleading claims to disparage their competitors, so whom does the market trust?  What do service providers endorse?  What products do people buy?  What do manufacturers make?  Or does everything just wait for the dust to settle and a winner to be decided?    And who gets to decide?

If we can just accept the fact that there will be many winners, each succeeding in markets where they fit customer needs, then it will be easier to cut through the hype, select a product that fits our application, and move on.

With all of that said, I must admit my bias so you can understand my perspective.  I work for Siemens, a leading global electronics and engineering company involved in almost every wireless networking standard out there.  My role is to serve as the communications chairman for the HomeRF Working Group.  Disparaging other wireless standards would only hurt sales of my companys other wireless products, so thats not an option.  While I naturally favor HomeRF for most wireless home networking applications, I promise to be fair in representing competing standards.

Introducing the Contestants: HomeRF and Wi-Fi (IEEE 802.11b)

The standards debate for wireless home networking is primarily in the 2.4 GHz band, between HomeRF and Wi-Fi, but it also includes Bluetooth to a lesser extent.  


The HomeRF Working Group created the HomeRF specification to meet the unique market needs of consumer households because no existing standard was up to the task. HomeRF extends beyond just data networking to also support cordless phones and streaming of multimedia content, even in the presence of severe interference.  Another HomeRF advantage is its smooth roadmap to supporting new devices, applications and services in the future; with data rates increasing to 20+ Mbps in 2002 and with full backwards compatibility with todays products.

HomeRF Chairman Ken Haase writes an article aimed at consumers and called, HomeRF is Changing the Way People Think about Home Networking.  Mike Maser of SimpleDevices, Inc. describes wireless benefits for entertainment applications in his article, Home Networking is Music to Our Ears Siemens, which is preparing a cordless phone system based on HomeRF, offers Telephony Unplugged: Next Generation Home Phone Systems. The integration of voice and data is significant because the cordless phone industry already has 98% penetration in U.S. homes and shipped 43 million phones last year alone, as compared to just 2 million wireless LANs to date.  

HomeRF is said to be relatively simple, secure, reliable and affordable.  For a user perspective of HomeRF and Wi-Fi, be sure to read the installation experience of Brian Cuban

For a more technical perspective on the market positioning and merits of HomeRF, read Kevin Negus article on Wireless Networking Choices for the Broadband Internet Home Leigh Chinitz contributed other technical articles supporting HomeRF and covering security, interference, and quality-of-service

Wi-Fi (IEEE 802.11)

The Institute of Electrical and Electronics Engineers (IEEE) designed 802.11 for data networking in large enterprise offices, but as described by Marco Cetto of Texas Instruments in "Wi-Fi Takes on Home Networking," 802.11 has many different variations: 802.11a, b, d, e, f, g and i. Marco neglected to mention that these separate working groups are required to operate autonomously and that security and quality-of-service enhancements are separated into different groups with little chance of completing their specs this year. Marco also failed to stress that differences in frequencies and protocols could prevent interoperability. This leaves 802.11 with infighting within the organization and a confusing roadmap to the future, which could cause consumers and service providers to replace their installed wireless networks several times as they are made obsolete by newer technologies.

WECA (the Wireless Ethernet Compatibility Alliance) is the organization that was put in place to market these engineer-defined standards.  WECAs mission is to certify interoperability of Wi-Fi (IEEE 802.11) products and to promote Wi-Fi as the global wireless LAN standard across all market segments.  This broad mission statement, in my opinion, repeats the mistakes of the Tower of Babel and goes against the natural order of things.  While I see a good fit for Wi-Fi in many markets, its a poor fit in most homes.

WECA argues that Wi-Fi is a logical choice for homes since the one standard can support wireless access at work, at home, and on the road at public access points.  Joshua Wise of Allied Business Intelligence agrees but ignores the problems that Wi-Fi faces in homes.  His article, Wireless LANs Enter the Home, starts to compare HomeRF and 802.11b and then only provides details on .11b.  This might suggest that he favors what he knows and doesnt know HomeRF.  Using ABI market forecasts, he concludes that 802.11 will achieve economies of scale faster than HomeRF.  HomeRF supporters counter that HomeRF exploits the much larger DECT installed base.  Europe already has over 50 million DECT-based cordless phones and base stations installed, and by 2003 that number will exceed 200 million.  That compares with less than 2 million 802.11 products installed today and ABIs forecast of about 10 million in 2003.

Companies such as Atheros Communications are starting to make 802.11a products at 5 GHz that are faster and have price points comparable with 2.4 GHz.  Many proponents of Wi-Fi say consumers can migrate in the near future from 802.11b to at least 54 Mbps performance with 802.11a, but others say the migration will be 802.11g instead.  Either claim is misleading, however, since these are two different protocols and frequencies.  802.11b uses DSSS (direct sequence spread spectrum) technology at 2.4 GHz; 802.11g uses OFDM (orthogonal frequency division multiplexing) at 2.4 GHz; and 802.11a uses OFDM technology at 5 GHz.   While it is possible to design products with multiple radio and antenna technologies, this would add cost and is not expected for consumer markets.

Introducing even more consumer options and controversy, Navin Sabharwal of ABI writes an article exploring 5 GHz WLAN Fragmentation and comparing the upcoming battle between 802.11a and HiperLAN 2 with todays battle between 802.11b and HomeRF.  The difference is that at 5 GHz the battle is geographic (Europe versus North America), while at 2.4 GHz the battle is over offices versus homes.

Also, the physics behind using this higher frequency poses significant problems for home applications and suggests that 5 GHz successes may be limited to offices for many years.  For 5 GHz, signal attenuation and range are the biggest barriers.  The higher the frequency, the more difficult it is for signals to pass through materials such as walls and floors.  Its the same as with sound waves, and this explains why you hear the annoying subwoofer of a passing car but cant hear the higher frequencies.  While this signal loss can be a major problem in homes, theres less attenuation in offices with open spaces and cubicles and the ability to extend the range by adding more access points.

Other Frequencies, Protocols and Standards

The media loves to write about standards wars, especially when engineers get religious in supporting their favorite technology.  Most people, however, dont care about technology.  They just want solutions to their needs, be it as simple as opening the garage door or monitoring the baby from another room.  And products serving these simple applications dont even need standards.  They can just as well use proprietary technologies.  

The use of standards does enable more complex applications and has other advantages.  With a standards-based baby monitor, for example, parents could add new functions such as sending images to any TV, PC, PDA or phone, whether within the house our remote.  Standards also improve the economies of scale of making components, and this helps drive down prices.  And standards enable products from different vendors to work together.  Certification testing ensures that they actually do.  Both HomeRF and Wi-Fi have testing programs, so buyers can look for their certification logos to ensure that products conform to the standard. 

While HomeRF and Wi-Fi are the primary contenders, there are other wireless frequencies, protocols and standards for use in homes.  But rather than cover each of them here, let's just acknowledge that they exist.  

The FCC has defined three license-free frequency bands at 900 MHz, 2.4 GHz and 5 GHz, which can be used for making consumer products.  2.4 GHz has been getting much of the media attention because it is starting to get crowded and interference prone.  That's due to its popular use for high-speed data networking.  It's the reason networking vendors are now talking about 5 GHz.  The early entrants into 5 GHz describe it as being relatively interference free, just as early 2.4 GHz manufacturers said 900 MHz was crowded.  But 5 GHz will eventually get crowded too.

Ideally, there should be no problem with mixing different frequencies and protocols, and it's likely that most homes will end up with a mix.  Market forces will help ensure that garage door openers, for example, continue to work even with interference from wireless security systems, cordless phones, and other devices that operate in the same 900 MHz frequency band.  If they dont work, they are returned for a refund.  Just read Brian Cuban's experience published in this issue.   

The rest of this month's column examines the differences in market requirements between homes and offices that will limit the long-term success of Wi-Fi in homes.  A future column will cover public places.

Up-market vs. Down-market

WECA promotes Wi-Fi in home markets for people who bring notebook PCs home from the office and want to use the same wireless LAN technology at work and home.  If you fit that description, then Wi-Fi may be a good choice for you, but you should understand some of the issues described briefly here and in more detail in other articles in this issue.  Assuming that you already have a Wi-Fi PC Card in your PC, all you need to get connected is a wireless access point.  Cost reduced models for home use are available for as little as $249.

The vast majority of office workers use a desktop or notebook PC that is wired to an Ethernet port and likely connected to a 100baseT Ethernet switch.  This gives them a dedicated high-speed connection thats far faster than the 5 Mbps maximum Wi-Fi throughput, which is shared among dozens of users.

While WECA contends that Wi-Fi will move down-market from enterprises to homes and that home networking standards will be determined by centralized enterprise decisions, the HomeRF view is that mass-market home networking standards will be determined by broadband carriers offering bundles of integrated services and needing ways to connect to PCs, TVs, phones, stereos, and appliances without running wires.

Theres also a philosophical view that says that disruptive technologies almost always move up-market and not down.  This view is supported by renowned Harvard professor Clayton Christensen in his book, The Innovators Dilemma.  

Its difficult to find an example of a technology that has successfully moved down-market but easy to find dozens where technologies first caught hold in consumer markets before then moving into enterprise markets.  Technologies that have moved up-market include the sound card, CD-ROM drive, DVD, digital imaging, color printing, mobile phones, cordless phones, graphical Web browsers, sales force automation software, Microsoft Windows operating system, and even the PC.

Even wireless networking has started to move up-market in one respect.  Individual users and departments are installing unauthorized wireless access points.  That trend makes the well-publicized security holes in Wi-Fi even more troublesome since it gives hackers an easy way to bypass firewalls that protect wired networks and servers.  The problem is so severe that IBM Research recently announced work on a device to locate these rogue access points so they can either be protected or removed. .  (see www.research.ibm.com/gsal/wsa )

While HomeRF was not optimized for large office environments and is not positioned for that market, its clear that HomeRF is finding its way into some offices, just as Wi-Fi is finding its way into some homes.

Home Environment vs. Office Environment

The physical environment of homes and offices are fundamentally different, and so are the types of things that cause radio interference.  These differences have influenced the design decisions for technologies targeting each market.

Homes have more objects that absorb radio signals, including plush carpets, drapes, and soft furniture.  Offices have more things that cause reflections, such as metal file cabinets.

Homes need enough range to cover the house and yard.  Large office buildings need an array of distributed access points and the ability to roam between them so users can move across and between floors or between buildings on a campus.

Homes have considerably more devices that cause radio interference, including microwave ovens, cordless phones, baby monitors, video senders, florescent lights, and other wireless networks.  Compounding the problem for homes is the fact that this interference can come from a neighbor, which makes it extremely difficult to know the source and nearly impossible to avoid the problem.  Note that many of these same interference issues affect small offices and retail outlets that also may have neighbors.

Larger offices, on the other hand, are relatively void of interference-causing devices until recently.  What has changed is the growing popularity of Bluetooth in mobile phones and PDAs.  Bluetooth has already become the biggest cause of interference in offices, and this problem will only get worse.

Each of the wireless standards has some means of avoiding interference, but their effectiveness in different environments can be an issue.  The frequency-hopping technology used in HomeRF was chosen for its superior interference immunity and then enhanced further.  For more on this topic, see Interference Immunity of 2.4 GHz Wireless LANs by Leigh Chinitz in this issue.

Home Apps vs. Office Apps

Office networks support data-centric applications such as e-mail, transaction processing and Internet access.  Slight delays due to latency or network contention are hardly noticed, but with so many simultaneous users, bandwidth is critical, especially since wireless networks are inherently much slower than wired networks.  Enterprises want the fastest wireless technologies they can get and will quickly move from 2.4 GHz to 5 GHz as products become available.

The applications used in homes extend beyond data networking used for Internet access and also includes entertainment and telephony applications, which have strict latency and quality-of-service requirements.  Only HomeRF supports the application needs of consumer households, which makes it ideal for broadband carriers offering bundles of integrated services and needing ways to connect PCs, TVs, phones, stereo systems, and appliances.  

Home Simplicity vs. Office Support

Early adopters of home networking have computing and networking skill from their office jobs, but this hardly represents the mass market.  While early adopters readily accept new technologies for competitive advantage or prestige, pragmatic consumers dont care about the technology inside their products.  They just want them to do the job easily, reliably and inexpensively.

Businesses are pragmatic too.  They hire support staffs so office workers can concentrate on business instead of technology.  But consumer households have no support, and mom isnt a good network administrator.

Personal Privacy vs. Corporate Security

Articles describing serious security flaws in Wi-Fi have corporate executives worried.  Its a trivial task for hackers to tap into their networks with off-the-shelf products, bypass their firewalls, and access sensitive information or do malicious damage.  These attacks can be done from a car parked outside or from an easy chair on a hill two miles away with a directional antenna.

Consumers using Wi-Fi are at risk since they often lack the skill to add extra security measures and may have a false sense of security, because they purchased a firewall to protect their Ethernet devices but are unaware of the wireless holes.   

While there are security risks in any network, HomeRF is inherently more secure than Wi-Fi due to its frequency-hopping technology, 24-bit network ID, and 128-bit encryption.  If you are interested in the details, see Leigh Chinitz article on, A Comparison of Security in HomeRF versus IEEE 802.11b.


Surely some Wi-Fi products will come into homes and some HomeRF products will go into offices.  But success for either standard will be limited to markets where their design "sweet spot." fits customer needs.  HomeRF continues to enhance its advantage for mass-market consumer households and is ideal for broadband deployments.  Wi-Fi continues to be the clear choice for business use in enterprises.  A more likely place for the two standards to duke it out is in public places, where today's demand is from business travelers and where Wi-Fi has established an early lead, but that's a subject for a future column.

After 30 years at IBM and running a home systems consulting practice, Wayne joined Siemens IC Mobile to help develop home networking strategies and apply cordless telephone technology to HomeRF, thus enabling the integration of data and voice applications.  Wayne is a home networking visionary, frequent speaker, and author with a monthly column in HomeToys.com.  He serves as the Communications Chairman for the HomeRF Working Group and can be reached at wayne.caswell@icm.siemens.com .

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