The push-to-talk (r)evolution: carriers are rushing to implement this walkie-talkie-like feature--and piling on new business features in the process.

WOULD YOU BELIEVE the hottest new offering in the mobile phone service market is 76-year-old technology? Push-to-talk (PTT) is an always-on communications service that gives wireless users a virtually instantaneous way to connect to users of the same mobile service--with just the push of a button. This technology, a basic operational function for two-way radios, has been available on walkie-talkies for many years.

A few years back, Nextel recognized that PTT meets different needs than standard voice telephony and launched Direct Connect, its PTT service. Nextel holds only 7.5 percent of the U.S. mobile phone service market, but it's a coveted share. Nextel has a strong following with business users, and these customers are extremely loyal. Nextel's churn, a measure of customers discontinuing service, is an industry-low 3.2 percent. And, Nextel's customers spend more money, averaging at least US$8 more a month per user than any other carrier's customers. Competitors attribute much of Nextel's success to Direct Connect PTT.

As a result, PTT is experiencing a renaissance as wireless phone carriers launch offerings to compete with Nextel Direct Connect. So far, only Verizon Wireless and Sprint PCS have taken on Nextel by launching PTT services, but Cingular, T-Mobile, and AT&T Wireless have all announced plans to jump into the PTT arena.

In addition to a subscription to PTT service, users need a PTT-capable handset. So, handset makers such as Sanyo, Nokia, Samsung, and Kyocera Wireless have announced PTT-capable handsets, hoping to take market share from Motorola, Nextel's primary handset maker.

This article gives a brief synopsis of some key PTT players, including Sonim, Kodiak Networks, fastmobile, Togabi, Qualcomm, Motorola, and Nokia. You'll get a high-level description of each PTT solution's architecture, plus information on how these companies are working with major carriers. I focus primarily on U.S. companies, but I also briefly cover what's going on in Europe and Asia.

The front-runner: Nextel

Using Nextel Direct Connect, a user's phone becomes a two-way radio that can immediately communicate with another Nextel phone. Nextel has added value to PTT by creating special networks users can subscribe to, such as its Transportation Network, which lets on-the-road workers, repair services, insurance providers, and others in the trucking industry communicate via PTT. A similar Builder's Network lets users get a strategic instant communication link to the people they need to reach the most: business associates, suppliers, and contractors--all via Direct Connect.

Nextel's Integrated Digital Enhanced Network (iDEN) is also a powerful wireless technology, combining the capabilities of a digital cellular telephone, two-way radio, alphanumeric pager, and data/fax modem in a single network. Nextel recently made improvements to the network to double its voice capacity and increase data speeds from an average of 15Kbps to 132Kbps. Even though all the major mobile carriers are considering jumping into PTT, some experts believe the newcomers' network infrastructures might not handle PTT connections as rapidly as Nextel's iDEN network. Nextel's proprietary iDEN network was built with PTT in mind, so there's only a brief delay when connecting (known as latency), usually one half to three quarters of a second. The other carriers are adding PTT to networks that weren't designed for it, so connection delays are an issue. Some reports put these PTT connection times at two to four seconds, a gap too disruptive for natural conversation.

To ensure they can compete even if their networks aren't as fast, sone of the carriers are considering adding new features such as presence awareness (the ability to know which of your contacts is connected and available for a chat) and other business features to convince consumers to adopt the service.

Sonim Instant Communications Solution

Sonim Technologies has partnered with Ericsson to provide an IP-based PTT solution interoperable over GPRS, EDGE, W-CDMA, and CDMA 2000 networks. Sonim is driving the industry's PTT standards toward a client-server solution with support for a variety of devices. Sonim's Instant Communications Client (ICS) is integrated at the chipset level and has been endorsed by chipset leaders such as Texas Instruments, Intel, Infineon, and Agere. This native integration on devices lets Sonim support PTT features not only on high-end smartphones, and PDAs, but also on mass-market phones where memory and processing power are usually limited.

Sonim Technologies has selected Force Computers to deliver its PTT solution. Force Computers has won awards for its EndurX High Availability (HA) system, which Sonim uses in ICS. As a result, Sonim promises mobile operators the 99.999-percent uptime (also known as five nines availability) they need for PTT.

Sonim's solution offers high availability but, like many new PTT technologies, it suffers from PTT setup delays, also known as latency. A couple of seconds might not seem critical--until you experience it. If you've seen TV interviews routed by satellite, you know how a two-second delay makes for difficult conversation, with awkward gaps followed by participants stepping all over each other's sentences.

As a result, Sonim has been persuading North American operators to go after markets Nextel has yet to penetrate with services Nextel doesn't yet offer. The family and teen markets are less sensitive to latency issues, which can be masked with a fake ring tone or a set-up process through which a user presses a button, sends an invitation and receives acceptance to start the PTT session. By the time the process concludes, a PTT session has begun. Sonim is offering some cool features these markets will value; for example, the ability to see who's available for a two-way chat. Dynamic group creation also lets users create walkie-talkie groups on-the-fly, a potentially compelling application for teenagers wanting to communicate with various groups of friends.

Kodiak

Kodiak Networks, a startup in the telecommunications industry, recently launched the only push-to-talk technology that leverages the wireless carriers' existing voice networks. As a result, the Kodiak system would let most cell phone users upgrade their handsets via a downloadable application. It would also let carriers quickly roll out PTT nationwide in any area covered by their cellular voice network.

Kodiak is also exploiting wireless audio technology that has been refined over the last 16 years. Latency is less of an issue for Kodiak. In addition to the higher performance of PTT on the voice network, carriers would be able to offer nationwide group conference calls, roaming on competitor networks, instant upgrade from PTT to a full voice call or conference call, integration between both CDMA 2000 and W-CDMA networks, call waiting, and the same kind of view of user availability that's available with instant messaging.

fastmobile fastchat

When fastmobile launched its fastchat PTT service in May 2003, leap frogging the carrier giants that were a long way from launching their own PTT technologies, many wondered whether fastchat would be the PTT solution to unseat Nextel Direct Connect. But, fastmobile is aiming at a far different customer: 18- to 25-year-olds who want to be one buttonpush away from friends.

Selling the idea as a low-risk alternative to copycat PTT solutions, fastmobile hosts the service, acting as an application service provider (ASP). As distributors of the fastchat Web-hosted service, carriers reap a monthly check from fastmobile without having to alter their networks. The carrier's only investment is the cost of integrating the service into its billing.

Togabi PacketCHAT

Togabi Technologies recently chose GoAhead Software's reliability middleware for its PacketCHAT PTT solution. Togabi is a leader in instant wireless communications services for network operators, and GoAhead provides an integrated suite of embedded middleware for highly reliable systems and applications.

Togabi's relationship with GoAhead lets it deliver dependable, next-generation wireless services. Togabi's PacketCHAT is an end-to-end suite of instant communications solutions, including PTT, voice instant messaging, and wireless chat. Available today, Togabi's PacketCHAT is currently undergoing extensive product trials with major domestic and international wireless carriers.

Togabi PacketCHAT consists of client software in commercial wireless handsets, and software infrastructure hosted on standard IP-based server platforms running in Intel/Linux and Solaris operating environments. The application supports all wireless packet networks including CDMA/1xRTT, GSM/GPRS, 802.11, and future 3G networks. GoAhead SelfReliant is cross-platform middleware that resides on the PacketCHAT server providing availability management, high-speed messaging services, in-memory database capability, and embedded systems management. These functions promise five-nines availability, milli-second failover speeds, preservation of the customer's PTT session state during an unrelated failure, and support for high-volume traffic. SelfReliant customers include leading network equipment providers.

Qualcomm

Qualcomm's QChat is a PTT communications technology for 3G CDMA networks. It doesn't use any proprietary hardware on the carrier side and it runs on any CDMA/1xRTT packet data network. QChat is a Voice-over-IP (VoIP) PTT application that enables instant, one-to-one and one-to-many half-duplex communication.

An interesting aspect of QChat is that it is implemented on the mobile phone as a software application. Qualcomm's Binary Runtime Environment for Wireless (BREW) provides the framework to manage the intersection of data and telephony features. Through it, existing BREW-enabled phones can support PTT by simply downloading the BREWChat client over-the-air.

The BREWChat software application was developed by QUALCOMM's Internet Services (QIS) division and was publicly announced January 10, 2002. It provides half duplex communication between QChat capable phones. It enables one-to-one (private) and one-to-many (group) calls over 3G CDMA networks.

Qualcomm's BREWChat software competes for handset-making customers with software from Motorola and Nextel, Togabi, and Kodiak Networks.

Push-to-talk handsets

The expanded PTT market is attracting handset makers such as Sanyo, Nokia, Samsung, and Kyocera Wireless who want to take PTT handset market share from Motorola.

Ahead of the pack is Sanyo. Its PTT models include the dual-band, tri-mode 5400 and the ruggedized, dual-band 7200. Both are available on the Sprint PCS network. Sanyo plans to release another PTT handset, the 8100, in early 2004.

Nokia recently unveiled its first PTT-enabled handset. In addition to PTT capabilities, the new 5140 phone includes a digital compass and integrated video graphics array (VGA) camera. In Asia and Europe, the 5140 operates in the 900, 1800, and 1900 frequencies and supports GSM, GPRS, and Enhanced Data Rates for GSM Evolution (EDGE) networks. In the Americas, the phone operates in the 850, 1800, and 1900 frequencies and supports the same Asian and European network technologies. No word on which wireless carrier will feature this handset. Nokia has hinted the price will be between US$140 and $190. Prices for Asia and Europe haven't been announced.

During 2004, Nokia plans to introduce a full range of push-to-talk GSM phones, including smart phones based on the operating system. All of its GSM and W-CDMA phones will include PTT starting in 2005.

Samsung is partnering with Togabi to build PTT handsets. The A690 has been announced, but there's no word from Samsung on when or where the CDMA handset will be released.

Kyocera Wireless is also joining forces with Togabi to make PTT phones available in early 2004. Kyocera, the parent company of Kyocera Wireless, has a strong relationship with Qualcomm, having acquired Qualcomm's CDMA consumer wireless phone business in February 2000 to form Kyocera Wireless. So, in addition to making phones that use Togabi PTT technology, Kyocera Wireless will continue to produce BREW-enabled phones, which will be capable of running Qualcomm BREWChat.

Motorola recently announced the arrival of its first CDMA/1xRTT mobile phone with PTT technology: the V60p. This introduction builds on Motorola's heritage as a PTT technology leader and marks the delivery of the first CDMA handset to complement the recently announced Motorola CDMA/1X PTT infrastructure server.

Setting the standard

PTT is clearly the most talked about subject in the wireless industry these days. Verizon Wireless and Sprint PCS have introduced PTT services solutions. AT&T Wireless has indicated it will commercially launch PTT in 2004, while Cingular Wireless has announced its interest in the capability, but hasn't provided any concrete launch dates.

Nokia, Siemens, and Ericsson are worried about the various fragmented PTT solutions coming to market. They're collaborating to come up with a VoIP open standard for PTT over GPRS and 3G networks. They are advocating a standard using the IP multimedia subsystem (IMS) platform developed by the Third Generation Partnership Project, the group developing standards for W-CDMA technology. Nokia expects to introduce a PTT product by the second half of 2004.

Sonim has been targeting the GSM market with its PTT thin-client solution, which is also based on the IMS standard, for nearly four years. The company reports market trials with European and North American operators, and recently announced an original equipment manufacturer deal with Ericsson. Ericsson just recently introduced its PTT solution for both the GSM and CDMA markets.

While operators hope that it--ironically, a voice application--might become the next killer application for the packet data world, it's difficult to envision a scenario where any carrier can unseat Nextel, at least in the near term. Competing PTT solutions for both CDMA and GSM face technical challenges that center around call latency and call set-up delays that range between three and 10 seconds, according to The Eon Group. Nextel operates a proprietary Frame Relay network that allows the carrier to connect users in less than a second.

Rather than compete with Nextel in the blue-collar business market, many of the carriers seem to be aiming for the white collar, family, and teen consumer markets. Nextel is looking at these markets, too. For example, Nextel, through a joint venture with Boost Mobile, is testing a PTT service offering for the teen market in California and Nevada. Nextel reported in the fourth quarter of 2003 that 3.8 million of the company's more than 11 million customers are white-collar individual users. However, the field is wide open because Nextel hasn't become an entrenched player yet.

No matter how the market and standards shake out, it's safe to say that walkie-talkie services aren't just for truck drivers and plumbers anymore.

MOBILE BUSINESS BENEFITS

Push-to-talk is a walkie-talkie-like feature for phones that's widely used by field force, repair, and construction workers, among many others. Although a regular call would work almost as well, there's something about the radio-like communication style of push-to-talk that keeps conversations short and to-the-point, making interruptions less painful.

Snapshot

U.S. carrier PTT plans

Nextel Direct Connect subscribers can choose a raze plan with a bucket of Direct Connect minutes or select one with unlimited Direct Connect minutes. Whoever initiates the call is billed for the minutes for both people on the call. In July 2003, Nextel went nationwide with Direct connect (meaning a user in California gets the same performance whether he's Direct Connecting to a user in New England or a user across town).

Verizon Wireless Push to Talk launched in August 2003, The monthly access fees for the service--which is an add-on to Verizon Wireless" America's Choice plans and includes unlimited one-to-one push-to-talk--range from $60 to $220, depending on the number of America's Choice voice minutes, which range from 400 to 3,200. The service supports Motorota's V60p digital handset.

Sprint PCS Ready Link launched in November 2003. Ready Link plans cost $15 per month for unlimited use, in addition to a standard voice services plan that starts at $35 per month. Customers have the same phone number for both voice and Ready Link services. Ready Link handsets include the Sanyo VM4500, the Sanyo RL2500, and the ruggedized Sanyo RL2000.

Cingular is looking into PTT, but has yet to announce specific plans,

AT&T Wireless is planning push-to-talk trials for 2004.

T-Mobile is looking into PTT, but has yet to announce specific plans.

John R. Vacca is an information technology consultant and internationally known author based in Pomeroy, Ohio. Since 1982, John has written 41 books and more than 470 articles in the areas of advanced storage, computer security, and aerospace technology (copies of articles and books are available upon request). John was also a configuration management specialist, computer specialist, and the computer security official (CSO) for NASA's space station program (Freedom) and the International Space Station Program, from 1988 until his early retirement from NASA in 1995. In addition, John is a freelance online editorial reviewer for Barnes and Noble. Finally, John was also one of the security consultants for the MGM movie AntiTrust, which was released in January 2001. [e-mail].