If the latest buzz around the cable industry is any indication, the familiar cable cliché of the "triple play," could soon be replaced by a new concept–"the quad."

Cable operators are now talking about developing technology and partnerships to add a fourth service–wireless voice–to the familiar landline voice, video and data lineup. Work is under way on technology that would allow wireless voice traffic to leap from the cellular network to a Wi-Fi home network backed up by a cable modem.

That could open the door for cable operators to offer a unified cellphone/home-phone service to their bundles and trump telco rivals. Cellular carrier partners, in turn, could use this roaming technology to offset peak traffic loads and solve the chronic problem of spotty in-home signal coverage.

Mike Smith
The groundwork for these cable/wireless offerings is already being laid, and moving to the front of the pack of the likely wireless partners is, appropriately, Sprint Corp.

"All of the cable guys get it–they all understand how important mobility services are today, and how they are going to continue to grow in importance. They see and understand as they position to compete with the ILECs head-on, that they are going to need some sort of wireless capability in their portfolio," says Mike Smith, director of business development at Sprint's Cable Solutions Group. "So we have open dialogue with many of them about how to do that."

A cable/cellular connection?

Indeed, cable technology minds have been kicking around the idea of a wireless/cable mind meld for more than a year, according to Marwan Fawaz, Adelphia Communications Corp.'s senior vice president and chief technology officer.

"Conceptually, the idea is for people to seamlessly transmigrate traffic from a wireless connection to a wireline broadband connection," he says. The technology pieces are in place with the recent development of wireless handsets with dual cellular and Wi-Fi capabilities, so "once you have a Wi-Fi connection, you can carry that traffic and funnel that traffic onto a broadband connection."

A new chip from Texas Instruments enables devices to
roam between cellular and Wi-Fi networks, opening the
door for a unified phone service tapping home
broadband and mobile connections.

Texas Instruments (TI) and Motorola Inc. have been working for some time on just such a technology. TI has developed a chip that melds a Wi-Fi radio with a cellular radio based on the GSM scheme. As part of its Seamless Mobility initiative, Motorola has incorporated the chip into its first hybrid enterprise product, set for debut late in the fourth quarter. The product will offer business customers a single phone, phone number and voice mail inside and outside of the office.

A version based on CDMA, the other dominant cellular technology, "is on our roadmap," says Chris White, director of business development for Motorola WLAN Seamless Mobility.

Meanwhile, Motorola's cable partners have been pressing for more details on the technology, "so we are going to try to hit residential trials in '05, and then work from there," says Rob Howald, director of IP systems engineering for Motorola's Broadband Communications Sector.

For the cable customer, the attraction would be not only the addition of cellular phone service, but also the possibility of a unified voice service. With a cellphone that can double as a home phone, they can pare down to a single phone and phone number–and potentially extend to other services, according to Fawaz.

"I think there are going to be other potential services that make it worthwhile–like unified messaging," he notes. "You want to be able to get one device and one number that you can get all of your messages on. You would now be able to use SMS (simple messaging service) more effectively because now you are in the home and you are not using a mobile network, so it is a lot more cost-effective that way."

A recent JupiterResearch survey indicated that more consumers–and particularly younger adults–are thinking seriously about making their cellphone their only phone.

"I think that is going to be the case as these younger consumers start to establish households of their own, there is only going to be increased willingness to go to a wireless and not have a landline phone as well," says JupiterResearch Senior Analyst Joe Laszlo.

Providing a connection between cellular and home Wi-Fi networks doesn't just benefit the cable operators. Cellular carriers including Sprint are also interested because it can offer a unified voice addition and help with traffic management. Offloading voice traffic from cellular networks might sound like a potential revenue loss, but it could be a plus, according to Mark Chall, director of service delivery for Sprint's Cable Solutions Group.

"Those are minutes that are not being sent over the CDMA network, allowing us to use that same asset for more customers," he says. "Plus, that probably helps our peak load."

It also could solve the vexing problem of in-home reception, since the phone would use the Wi-Fi network in the home, rather than a distant cell tower.

"I think that's a value add to the solution for us, is that it does truly extend higher-quality interconnection to many homes that are on the fringe of our network," Chall says.

Technical difficulties

Remi El-Ouazzane
But as with any new technology, there are challenges, and one of the first is working out how the actual handoff will occur. The Motorola enterprise product uses a PBX call manager to pass calls between the two networks, but that won't exist for a residential play. To date, the handoff technology overall is not quite nailed down, according to Remi El-Ouazzane, marketing director for TI's mobile connectivity solutions business.

To transfer calls without dropping them requires development of a switch in the network that can transform the packet voice traffic from the Wi-Fi/cable network to the switched network used by cellular, and vice versa. In the interim, consumer Wi-Fi/cellular phones will likely not have the handoff feature, so a call initiated in a Wi-Fi home will drop if the caller walks out of range.

"It's just a question of implementation," El-Ouazzane says. Subscribers could still use a single phone, so "I don't see that as something which will kill the business. It is just something that will become an enhancement."

Making sure that the voice signals are treated properly as they pass between the largely circuit-switched cellular grid onto the IP wireline network also is an issue.

"You are dealing with an IP backbone, as opposed to the protocols that have been developed for wireless handoff," Howald says. "So what we have to do is look at protocol stacks, processing requirements–because you have got to take care of latency issues and jitter, which are all of the things that IP doesn't inherently do well–and make sure they are employed properly."

That is a problem cable operators could help solve more effectively than their digital subscriber line rivals. Armed with the PacketCable Multimedia specification, they could set quality-of-service and signal prioritization levels for wireless voice traffic as it flows over the IP connection.

"Voice traffic needs to be treated with TLC. Today there might be bandwidth and capacity to support just about any kind of broadband service with decent latency and jitter, but it's not clear over time how that is going to hold up," says Motorola's Howald.

To that end, CableLabs last year formed a committee to look into an extension of the PacketCable Multimedia specification for wireless to wireline service.

"And so in terms of quality of service and in terms of what kind of media gets transported, that's what we've been looking at–how to deliver information from that mobile network over the cable access network to the client device, and what particular traffic profiles need to be supported," says Glenn Russell, director of multimedia applications and a member of the advanced network systems department at CableLabs.

But the work also requires a crash course in cellular wireless technology. Compared to the PacketCable Multimedia specification, the array of cellular standards and transmission technologies "are orders of magnitude greater in terms of the different kinds of cellular protocols and the evolution of those protocols that need to be factored in," Russell notes. "So a lot of the lifting that we are doing right now is kind of digging into that work and making sure we get the right people involved and that we're aware of the right documents and the right specs and other communities."

As a result, there is no timeline for when a PacketCable Multimedia profile for wireless could emerge, he says.

Choose your partner

Technology aside, finding willing wireless partners also is a challenge. Given their ownership ties to archrival telcos, the two largest nationwide cellular carriers–Verizon Wireless and Cingular, once it completes its merger with AT&T Wireless–are not likely candidates.

Of the remaining big cellular players, Sprint has been the most aggressive in pursuing cable alliances. In August, it forged a deal with Mediacom to provide voice-over-IP services to its 1.5 million cable subscribers in 23 states. While that deal involved only wireline voice, the intention is to evolve into a wireless service, according to John Pascarelli, Mediacom's executive vice president of operations.

"The deal itself addresses the opportunity of adding wireless to our bundle," Pascarelli says. "The details of that have not been worked out yet, but we both agreed it is an opportunity for both of us that makes sense. And now that the actual landline piece of it is done, the focus now will be on working out those arrangements that will make sense for both of us."

Mediacom would probably start as a Sprint PCS reseller, but Pascarelli expects that to evolve into a direct link between cellular and cable Wi-Fi connections at home and beyond.

"I think the long-term vision is that you will have one phone that you just take with you. As a company, as an industry, we'll set up wireless hotspots in high-traffic areas that will take the traffic to our network, and where there isn't one available, there will be a cellular wireless network," he says.

If such relationships do evolve to include wireless, another issue to be tackled will be an old favorite among telecommunications providers–the back office systems needed to authenticate, track and bill the service as it moves between the wireless and wireline carrier.

"It's a lot of those logistics that have to be worked out over time, but they are not significantly different than the issues the telephone industry has already worked out with long-distance providers and CLECs and having interconnect relationships and other things," Pascarelli notes. "It's really more of the same. It's just a matter of different partners and a different technology."

Beyond voice

If such partnerships prove out, in the future, roaming could extend to include wireless data.

"Today we talk about it as voice service, but over time, obviously, cellular operators are trying to do wireless broadband," Howald notes. "Clearly, cable is fixed broadband service, and ultimately there could be a nice marriage between cable operators and cell operators on the data side as well, if they establish these relationships with voice."

Sprint's Smith also sees a roadmap that extends beyond just voice. He points to recent Sprint demos at cable shows where Sprint picture mail is sent to a TV screen via the set-top box. And Sprint's addition this summer of a handset that can stream video at 10 to 15 frames per second could also allow video possibly to flow from the set-top to the handset.

"The cable guys see a lot of potential for that kind of a service, streaming trailers for pay-per-view or advertisements they would put on a local cable channel," Smith says.

With cable operators actively looking for ways to extend their cable modem services and a ready technology link, adding a wireless play is more than likely, according to Laszlo.

Industry wide, it is more than likely that some form of cable/wireless alliances will be forged. "Just the way that the telcos are striking deals with the satellite TV providers to add video to their bundles, I think we'll see cable operators seeking out wireless partners," he says. "It makes perfect sense to find ways to tie a voice over IP over broadband offering to wireless."