A new era of data communications is being ushered in in the US, as an open standard for high-speed wireless transmission of packetised data over existing cellular network begins to gain momentum. The standard, Cellular Digital Packet Data, CDPD, was born in April 1992, when IBM Corp, along with a group of cellular carriers, announced a co-operative effort to develop specifications for an open industry standard for transmitting data over cellular communication systems. The brief was to use existing technology as its building blocks, with initial protocol support to include Internet IP and Open Systems Interconnection CLNP. The carriers numbered McCaw Cellular Communications Inc, Ameritech Mobile Communications Inc, Bell Atlantic Mobile Systems, Contel Cellular Inc, GTE Mobilnet, Nynex Mobile Communications, PacTel Cellular, Southwestern Bell Mobile Systems and US West Cellular.
Las Vegas
At the heart of Cellular Digital Packet Data is IBM’s CelluPlan II technology, which enables idle time on cellular systems to be filled with packets of data, providing a wireless data service with a transmission rate of 19.2Kbps. Adherents of the technology claim that it is not only up to four times faster than competing wireless services, such as the radio-based Ardis and RAM Mobile Data offerings, but that it enables data to be transmitted across existing cellular networks without disrupting or degrading voice traffic. The Cellular Digital Packet Data specification was launched in three phases. The 0.8 version, released in March 1992, provided developers with an overview of the CDPD architecture, encryption and authentication, network support services, network application services, network management and a detailed description of the airlink – the portion of the specification defining how subscriber equipment interfaces with the cellular radio frequencies. This was followed by the 0.9 version in late April, which included additional information on the network interface. These were then touted round the industry for comment and the Cellular Digital Packet Data project culminated, in August this year, with a published version 1.0 of its full open specification, which was presented to the Cellular Telecommunications Industry Association and the Telecommunications Industry Association for adoption as an open standard. Kirkland, Washington-headquartered McCaw Cellular Communications Inc has now catapulted Cellular Digital Packet Data into the real world by becoming the first carrier to go live with a CDPD service, called AirData. Now on line in Las Vegas, where it was announced at Comdex Fall, McCaw says its AirData Cellular Digital Packet Data service will be rolled out in Dallas, Miami, New York, San Francisco and Seattle by January, and will be supported by its entire existing cellular network by mid-1994. McCaw’s Cellular Digital Packet Data pioneers will include American Airlines’ Sabre Technology Group and the Insurance Value Added Network Services, a purchasing organisation for 400 insurance companies – both of whom plan to test the service early next year: American Airlines will be piloting an airline reservation application developed in-house and has already demonstrated the wireless reservation terminal it intends to use with the service; while two or three Insurance Value Added Network Services members intend to test the technology in the Las Vegas metropolitan area using Cellular Digital Packet Data-equipped IBM laptops, enabling claims adjusters and premium auditors to retrieve information remotely from centralised mainframe databases over the Advantis network.
By Ian Holland
Much of the success of AirData will hinge on what users will be prepared to pay for the service: McCaw is coy about holding up a per-packet charge as a base-line price, saying instead that it intends to charge between $34 to $45 per month for each user once it begins to market to consumers, on an all you can eat messaging basis. For the business market, which McCaw is targeting first, contracts will be negotiated individually. Other carriers have be
en equally bashful about talking pricing, but are likely to price similarly to McCaw. The other determinant of AirData’s success and, by extension, Cellular Digital Packet Data’s, will be the availability of equipment, and its delivery timetable – one of the reasons that McCaw is hitting the corporate market first is that CDPD modem equipment will not be widely available until next year. Originally, McCaw had planned to roll-out the service in half the 105 markets it serves by the end of the year, but delays have occurred due to equipment shortages. McCaw says that the carrier’s suppliers of Cellular Digital Packet Data mobile data base stations – Pacific Communications Sciences Inc and Steinbrecher Corp – have not been able to deliver the volume of equipment needed to reach that goal. Nevertheless, the equipment market is beginning to expand, and analyst BIS Strategic Decisions estimates that 200,000 to 500,000 units of Cellular Digital Packet Data modems will be shipped by the end of 1994. Network manufacturers with CDP projects under way included AT&T Network Systems, Cascade Communication Corp, Hughes Network Systems, Pacific Communications Sciences Inc and Steinbrecher Inc. Despite Motorola Inc’s commitment to specialised, data-only cellular systems, it too plans Cellular Packet subscriber products for consumer and industrial applications. On the software side, Alcatel TITN, Cellular Data Inc and Retix Inc are developing systems to drive the Cellular Packet engines and Apple Computer Inc, Eo Inc and IBM Corp have already demonstrated Cellular Packet Data-enabled devices.
Easy deployment
How AirData – and Cellular Digital Packet Data – will fare is still an open question. Despite the fact that it rides on an existing $20,000m cellular infrastructure, which should make for relatively quick and easy deployment, and that it is a de facto open standard, potential users are cautious: according to the Insurance Value Added Network Services strategic technologies department, the key to Cellular Digital Packet Data is whether users can keep their applications the same and adjust them to interface to a CDPD device driver. US-wide access is also paramount in potential users’ minds, although McCaw is confident that this is a non-issue, predicting that by the end of 1994 Cellular Digital Packet Data will have 74% coverage of the US population, McCaw itself accounting for 43%. Implicit in this statement is that McCaw is not going to be the sole operator for much longer: in fact more than a dozen carriers have promised to link their networks into a Cellular Digital Packet Data internet, and some are on the brink of going live. GTE Mobilnet has already announced that its deployment of CDPD will be initiated shortly in Northern California, and Bell Atlantic Mobile Systems has said that it will begin installation of a Cellular Digital Packet Data system in Pittsburgh by the end of this year; Ameritech and PacTel have also announced their intention to roll out in 1994, the latter starting in San Francisco. The clout of the carriers, eager for additional opportunities to exploit their franchises, and the bandwaggon-jumping of third party vendors, need not mean that Cellular Digital Packet Data will take off, but one US analyst at least is bullish about its chances: McCaw will thaw the frozen [wireless] market, says Forrester Research in its September Network Strategy Report, ‘Getting Wireless Unstuck’. Once this happens Forrester concludes that the wireless market will gel around Cellular Digital Packet Data.
