There are three trends in home phone systems: (1) the move from one phone number per location to one number per person, (2) the delivery of voice services over more efficient digital broadband networks, and (3) the continued evolution of cordless.  These three trends are converging on the Internet broadband home at an increasingly fast rate.

This paper starts with a look at these trends and then examines a new cordless phone technology, HomeRF that has the potential of becoming the first global standard.  HomeRF voice support extends the European Digital Enhanced Cordless Telephony standard (DECT) and enables the integration of voice services with high-speed data and streaming audio, video and gaming applications on telephone handsets and other devices.

The paper concludes with the author’s vision of how these three trends might converge into a next generation phone system.

From Party Lines to Personal Lines

Grandma’s first phone shared a party line with a dozen others along rural route 1084.  Each home tapped into the daisy chain wiring scheme that connected to the telephone company.  I never really knew those days, and instead most of us grew up with one phone number per household even if some of us had more than one phone extension sharing a single line.  There was no need for an operator to make the physical circuit connection – just dial a number and an automated switch connected us. 

Many of today’s busy households already have a second line, but adding a third is difficult.  That’s because most house wiring has only two pairs of wires to support two lines, and the RJ-11 phone jack itself supports just two lines. 

Why just two?  Don’t builders understand that teenagers each want their own phone number, and home offices need a business number a fax number?  And what about out-of-town visitors?  Must they now give out our unlisted phone number?

One Phone Number per Person versus One Number per Location

With falling costs, mobile phones are starting to replace wireline phones.  At least 2% of U.S. homes (about 2 million total) have tossed out their wired phone and now use cellular instead.  Depending on which survey you look at, the estimate of cellular replacing wireline may already be as high as 7% of households. 

Mobile phones offer a personal phone number that can be reached anywhere – at home, at the office, while shopping, or when traveling.  And most mobile phone services include plenty of free long distance with monthly costs that rival what most of us pay for local and long distance service plus added features such as call waiting, call forwarding, and voice mail – features that are typically included in cellular services.

Falling Costs

Back in 1984, cell phones cost about $3000; airtime was more than $1.30 per minute; and there were less than 100,000 U.S. subscribers.   Even without hardware subsidies, my newest mobile phone cost less than $200.  It shares a family pool of airtime minutes and adds only $10 to the monthly service charge, which for all of us is less than $80 per month.  Yes, everyone in our family now has his or her own phone, and this makes it easier to stay in touch with each other.  While we haven’t dumped our local wireline phone service, I’m looking forward to digital broadband telephony eventually replacing that analog service.

More Personalized

Mobile phones give us the ability to customize our phone use by changing the handset color, ring tone or song, menus, preferences, user interface, loudness, speed dials, and voice mail announcement.  Modern phones also support Internet access, the ability to have personalized ‘Net preferences, a contact list, and even applications that are downloaded from the Internet.

But there are Geographic Differences

Whether you call the service mobile, cellular or wireless, user adoption varies by geography.  The U.S. mobile market lags far behind Europe and Asia, largely because those areas settled on one common standard while in the U.S. we still have several, including PCS, GSM, CDMA and TDMA.  These different standards are progressing along different roadmaps through GPRS and EDGE to 3G.

And Spotty Cell Coverage

One of the biggest barriers to using mobile phones in homes is the lack of coverage.  Cellular networks do a good job covering business districts and interstate highways but generally don’t have good coverage of residential neighborhoods.  Thus, poor signal strength can prevent many households from replacing wireline phones with wireless. 

Broadband Voice

Voice communications and simple text-based data are giving way to rich multimedia information of all sorts, including digital music and video with bandwidth requirements that burden the public switched telephone network (PSTN).  Because of the very graphical Internet, data traffic has far surpassed voice traffic, and many analysts are surprised that the U.S. phone system hasn’t crashed yet, although that possibility still exists. 

Communications carriers are responding by upgrading old analog networks with new digital technologies, but the upgrade costs are staggering – measured in hundreds of billions of dollars.  To justify the large investment, carriers are starting to offer bundles of integrated services including voice, data, music and television over their broadband networks. 

PSTN moves to Digital Packets

While analog dialup connections that operate at 56 Kbps or less, broadband suggests speeds ranging from 128 Kbps to more than 1 Mbps over always-on network connections.  The most common broadband technologies are cable and DSL.  Both have the ability to group voice calls and other information into data packets carried on a single network. 

While telephone companies use digital subscriber line (DSL) equipment to extend the capacity and usefulness of their twisted-pair phone wires, cable companies use cable modems to extend the use of their coaxial cables.  Less popular broadband technologies include satellite, fixed wireless (MMDS), and various forms of cellular networks. 

As shown in the bar chart, some 10 million U.S. homes already have broadband cable or DSL service, up from 5 million in 2000 and going to at least 28 million in 2004.

Broadband Bundles Feature Voice Services

Carriers are already starting to offer bundles of integrated services that lower operational costs and increase customer loyalty with more value, a single monthly bill, and one support number to call if there are problems.  Broadband networks also enable these carriers to offer new and additional services over time, while at the same time locking out competitors. 

I currently pay about $190 per month for local, long distance and wireless phone services plus another $125 for television, broadband and security monitoring services.  It’s no wonder I’m looking forward to replacing this collection of individual services with a lower cost bundle that should save me about $100 per month.

If the cable company offers this bundle, they can earn an additional $100 per month.  If the local phone company offers it, they can get another $150.  Bundling is a win-win for customers and service providers alike – and a big looser for the service providers that are left behind.  Eventually, this vision is expected to result in commodity pricing of individual services and fierce competition that places slow moving incumbents at risk of loosing customers. 

Cable Telephony Deployments

While telephone companies are starting to use their new broadband networks for video-on-demand services, cable companies are adding telephone services.  Deployments of voice over cable are on the increase even though multimedia data gets most of the public attention.  Overall, voice still generates most of the revenues and pays the bills.

Some of the cable companies testing or rolling out voice services include:

•  AT&T– Atlanta, Boston, Chicago, Dallas, Denver, Detroit, Hartford, Jacksonville, Los Angeles, Pittsburgh, Pompano, Richmond, Salt Lake City, San Francisco, Seattle

• Cablevision – Fairfield County CT and Long Island NY

• Charter – Duluth GA, Ft.Worth, Pasadena, St.Louis

• Comcast – Alexandria VA, Price Georges County MD, Prince William Counties VA

• Cox – Hampton Roads VA, Hartford CT, Oklahoma City, Omaha, Orange County CA, Phoenix, San Diego

• Time Warner – Austin, Honolulu, Portland ME, Rochester, Tampa

Source:  Parks Associates and Pulver.com

Broadband Drives Home Networking

While the Internet and multi-PC households have driven early adopter demand for home networks so far, it’s broadband that will take home networking into mainstream households.  That’s because carriers offering bundles of integrated services need ways to connect to PCs, TVs, stereo systems, game consoles, and telephone handsets.  Since it isn’t feasible to dispatch installation crews to drill holes and pull wires, broadband carriers will promote the use of no-new-wires home networking.

HomeRF is ideally suited for broadband since it supports a variety of broadband services with high quality and without running wires.  It’s great for cable companies offering telephone services since they must find ways to reach the handsets.  Phones don’t plug into coax outlets, and there’s usually no phone outlet near the entertainment center where the coax outlet is.  HomeRF includes high-quality cordless phone support, and Siemens will introduce the first HomeRF phones this Fall.

Because HomeRF supports up to eight toll-quality voice lines simultaneously, broadband carriers can allow each family member to have his or her own number and remotely provision new phone numbers and services.  Rather than being limited to just two phone lines, broadband customers with HomeRF will be able to activate additional lines as younger kids grow up, when older kids come home from college, or when visiting guests arrive, even transferring their own number.

Cordless is Convenient

With so much hype around the Internet, high-speed data networking, and wireless LANs, many of us have lost sight of a much larger market – cordless phones.  At least ten times more cordless phones ship each year than wireless LANs, and twice as many cordless phones are sold than corded phones.  The cordless phones cost twice as much, and there’s no U.S. standard to drive down prices or ensure interoperability.  So, the market success of cordless phones simply proves that consumers are willing to pay a premium for convenience.

Cordless phones are so popular that American families often have several, but each one stands alone with a base station that plugs into a phone outlet.  What if there are no outlets where you want the phone?

Several companies now make multi-line, multi-handset phone systems based on 2.4 GHz radio technologies.  With a base station plugged into a phone outlet, additional handset chargers can be placed anywhere within range of the base.  These phone systems also bring PBX-like functionality to homes and small businesses, but their biggest success has been in businesses.  That’s largely because of relatively high cost compared to 900 MHz phones and the fact that proprietary technologies lock you into one system.  If there were a standard for cordless phones, handsets from AT&T, GE, Panasonic, Sony or VTECH could work with a base station from Siemens, and visa versa.  And a standard would help drive down prices.  HomeRF expects to become that standard.

DECT was the First Cordless Phone Standard

The European DECT standard was originally approved by the ETSI (European Telecommunications Standards Institute) in 1992.  The standard is now mature and widespread in Europe, adopted by over 50 countries, with support from over 100 certified DECT suppliers, and now using 5^th generation chip sets that are available at very low price points.  Over 50 million DECT phones and base stations were sold in 2000 alone, and analysts expect the installed base to exceed 200 million in 2003.

DECT defines the radio interface between a cordless phone base station and mobile handsets.  It sets up a mini-cellular network for in-house voice communication and can be enhanced to support data networking at speeds up to 2.88 Mbps.  Unfortunately, the DECT standard is unavailable to countries outside of Europe since it’s based on 1.88 to 1.90 GHz frequencies.  In other parts of the world, that band is already reserved for mobile phones and other devices, so DECT use would require a license. 

HomeRF is poised to become the Global DECT Standard

Siemens, the world’s leading manufacturer of DECT-based phones with sales of over 30 million units, has applied its telephone expertise to HomeRF and is working with DECT Forum to promote HomeRF as the Global DECT standard. 

HomeRF can extend the DECT standard beyond the bounds of Europe since its voice technology is derived from DECT and operates in license-free 2.4 GHz frequency bands, which are available worldwide.  HomeRF also adds the ability to integrate higher-speed data networking with peak rates up to 10 Mbps in 2001 and multimedia streaming with prioritized quality of service – all on a telephone handset or other device.

Like DECT, HomeRF doesn’t rely on line-of-sight connections and can penetrate walls.  Its range covers a radius of about 50 meters indoors and even farther outdoors.  And its adaptive frequency-hopping technology and dedicated voice time slots ensure that HomeRF provides equally high levels of security and noiseless speech quality.

HomeRF supports all CLASS service features like call waiting, caller ID, forwarding to individual handsets, distinctive ringing, 911 breakthrough, etc.  And unlike its 2.4 GHz wireless LAN competitors, HomeRF’s 2002 roadmap to 20 Mb/s or higher with full backwards compatibility is not dependent on FCC rule changes.

Only HomeRF provides simultaneous support for up to 8 toll-quality voice connections, 8 prioritized streaming media sessions and multiple Internet and network resource connections at Broadband speeds.  HomeRF accomplishes this with excellent comparative ratings for simplicity, low cost, small size, low power consumption, interference immunity, security, and support for high network density.

HomeRF Voice Technology

The HomeRF Working Group first developed and agreed to a set of market requirements for consumer households, which were based on extensive study and ethnographic market research.  The group then went looking for technologies to meet those requirements, hoping to find a single technology to endorse, but it instead found that no one technology could meet all of the requirements.  So, the group combined several technologies as shown in this block diagram.

A physical layer describes the 2.4 GHz FHSS radio technology.  The MAC layer defines a blend of protocols.  CDSMA/CA protocols were derived from IEEE 802.11 and simplified for consumer use of TCP/IP data networking applications.  Quality-of-service for multimedia streaming applications such as digital music, television, and gaming required the addition of a priority scheme to support UDP/IP.  And HomeRF voice support uses TDMA (time division, multiple access) protocols derived from DECT.  The result is a blend of several international standards that uniquely meets the market requirements.

HomeRF is an open specification that is available to member companies.  The entire spec is over 500 pages long, but you can get a good technical understanding from a set of white papers available at www.homerf.org.

HomeRF demonstrates its First Voice Call

In May, Siemens, a leading global electronics and engineering company, and Proxim, the pioneer in wireless broadband networking, demonstrated the first HomeRF voice call using a Siemens cordless handset and a Proxim wireless gateway, which included a Voice Data Module (VDM).   The first demo connected to the PSTN, but this Summer the companies will demonstrate HomeRF voice capabilities integrated with cable and DSL platforms, and this Fall they will start field trials with a major broadband service provider.

"Siemens and Proxim are proving that high quality, integrated voice and data over a single wireless home network will be a reality in the near future," said HomeRF Working Group chairperson Ken Haase.  Ken went on to say that voice-data integration opens the doors for a wide-range of products and services, including applications designed for PCs, web pads and other home and small office network-connected devices. The combo also sets the stage for next-generation services from telephone carriers, home automation companies and independent software vendors.

The impact of Voice / Data Integration

By integrating voice and data services on the same telephone handset, an existing home PC can enhance the phone system, and a high-quality cordless phone can enhance the PC.  For PC manufacturers, such integration should help them to sell more PCs.  Likewise, such integration can also drive sales of more phones and related services.

The first implementation of voice and data integration will enable the PC to display simple text information on telephone screens and respond to button pushes.  A PC can simplify setup of the phone system, can chime when new emails arrive and display their contents, and can act as an interface between phones and home control systems.  With the eventual availability of XML scripting enhancements and developer toolkits, 3rd parties are expected to develop voice-enabled applications for HomeRF.

Expected later is the ability to use the phone as a speech input/output device for running PC and Internet applications:

“What messages do I have?”

“Forward that to …”

“Turn off the upstairs lights.”

“What is the weather in…?”

“What is Siemens’ stock value?

“Buy 50 more shares of Siemens.”

HomeRF offers Superior Scalability

The earlier comment about high network density refers to apartments or any other environment where other 2.4 GHz networks may operate within range of your network. 

HomeRF uses a FHSS (frequency-hopping digital spread-spectrum) technology that allows it to identify interference within the band and ensure with high probability that the next hop is into the clear.  That ability to adapt its hopping pattern is key to delivering high speech quality.

IEEE 802.11b, because it was designed for enterprise office environments and not homes, uses a DSSS (direct sequence spread-spectrum) technology that locks onto one of three non-overlapping channels within the same 2.4 GHz band.  That design decision lets IT technicians tune their wireless networks by determining the ideal placement and channel assignment of access points.  The 802.11b technology is ideally used where there’s little chance of RF interference, such as in large enterprises, airports, warehouses, and schools.  But 802.11b can have major problems when interference is likely, such as in apartment buildings, neighborhoods with nearby houses, office parks with many small and independent businesses, etc.  And 802.11 has no QoS guarantee or voice support.

The biggest worry I have about 802.11b is that it is starting to move from enterprises into some small businesses and homes.  With no interference, performance can be adequate, and a business owner may rely on his new wireless network for mission critical applications, even boasting about the benefits of going wireless.  Future interference problems can come in two areas:  (1) new wireless LANs installed by a neighbor, and (2) 2.4 GHz phone systems installed by a neighbor. 

Interference caused by wireless LANs is just an annoyance, causing both networks to slow down.  But the cordless phone systems designed for small businesses can completely shut down an 802.11b network – for the entire duration of phone calls.  When news stories appear to describe how wireless networks can cause loss of business, consumer trust in wireless can be hurt, and market development within the wireless industry can stall.  The industry has already been hurt enough by well-publicized stories about severe security concerns with 802.11.

What about Voice over IP?

VoIP is a technology used to send voice conversations over data networks using Internet protocols, such as Ethernet (or wireless Ethernet).  There are two current problems with VoIP: cost and interference. 

Cost – VoIP found early success with telephone headsets attached to PCs, usually for cheap long distance connections over the Internet.  The traditionally poor voice quality has improved dramatically in the last few years due to QoS (quality-of-service) improvements in the access networks from companies such as Cisco.  Sadly, an IP phone that requires no PC is still too expensive (beyond consumer price points, at over $500 per handset).  Although Moore’s Law will eventually address this cost issue, IP phones will remain expensive for many years.  That’s because the phones must include an embedded PC to handle the IP protocol stack. 

Interference – A bigger issue is interference.  As long as there is no other network traffic to interfere with voice services (and no outside interference), then good voice signals can get through, but interference is common and voice quality suffers.  Ethernet is a contention-based network with no QoS, and wireless Ethernet adds the possibility of RF interference.  A better way to make an IP cordless phone is to run IP on top of HomeRF since it has strong QoS guarantees and interference immunity.  A far better solution is to bypass VoIP entirely and use native HomeRF voice support instead.  It has superior phone quality, the lowest cost, and the most phone features, all with a standardized solution.

HomeRF – Enabling a Next Generation Phone System

Combine the three trends discussed above: broadband voice, personal phone numbers, and HomeRF cordless telephony, and you may come to this vision of a next generation home phone system.

A single service provider offers more value and new capabilities with their bundle of integrated services as described above.  Family members have their own personal phone number and personalized handset.  That one number can now reach them at home, in the office, in the car, at the mall, or at Grandma’s house in San Antonio, assuming that they haven’t turned off their phone.

Come home and plug your mobile phone into a charging unit, which tells the service provider where you are and that calls to your personal number can now be directed home over very efficient broadband networks instead of relying on the more expensive airwaves.  Each charging unit speaks HomeRF, as does the residential gateway that sits between your wireless home network and the services you want.

Throughout the house, a variety of phones from different manufacturers now interoperate and can all be used to answer incoming calls, make outgoing calls, and call room-to-room, as well as run PC and Internet applications.  They may each get a distinctive ring based on caller ID so you know if the call is for you.  A messaging service that’s available from home or anywhere else combines voice-mail, e-mail, faxes, and paging messages.

Your HomeRF wireless network becomes an integral part of this next generation phone system and is ready for video telephony and other new and demanding applications.  The HomeRF products you buy today are well matched to broadband data applications at 1.6 Mbps, and the new HomeRF 2.0 products that support video and data networking with speeds up to 10 Mbps will work seamlessly with current products.  More importantly, you, your service provider, and the device manufacturers can all feel secure in knowing that next generation HomeRF 3.0 products expected in 2002 with speeds of 20 Mbps or more will continue that smooth upgrade path.

While I’m interested in learning more about the other visions of the next generation home phone system, including the use of only mobile phones or IP phones; each has significant technical obstacles to overcome.  If I were a betting man, I’d bet on HomeRF.  I have.

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 .