July/Aug 2004

If you're transmitting data to and from vehicles and mobile workers, GPRS isn't the only option. Dedicated networks, some with voice capability, still can offer a convincing alternative, says Sharon Clancy

Are you trying to decide the best technology for sending data to and from your mobile workforce? With the demise of Inquam's Dolphin network at the end of July and the stalling of QuikTrak's UK expansion through lack of funding (see News Update, page 5), it's easy to get the impression that dedicated radio-frequency data networks are old hat, and that all-pervasive GPRS or 3G cellular networks are the only viable option - especially if your business demands a real-time always-on connection and frequent data transfers to and from mobile units.

Admittedly, new applications are still emerging for TETRA (terrestrial trunked radio), the digital standard that was used by Dolphin, which combines voice and data communications. But for the time being suppliers in that market are targeting only public safety organisations such as the police and emergency services.

Dedicated data networks are, however, alive and well in the commercial market, and some would argue they are better suited for logistics applications than a cellular network. Advantages include fixed costs, a robust network, coverage even when GPS and cellular signals are weak, and enhanced security in tracking applications (because signals are harder to ham).

 

It's also worth taking note of warnings that the growth of consumer-orientated data traffic could mean some GSM networks may struggle, in the short-term at least, to supply sufficient data capacity at peak times. And although there are certainly some attractive GSM/GPRS pricing plans out there at the moment, they might seem less appealing if the network operators changed their current pricing plans to steer traffic away from peak periods, or introduced more precise charging structures to maximise revenue streams.

Dedicated data networks are based on RF (radio frequency) technology, in which signals are transmitted around a nationwide network of radio beacons. They tend to use UHF frequencies for voice communications and LF (low-frequency) for vehicle tracking purposes. They offer inherently greater resistance to signal jamming, plus increased security, and UHF radios allow communications inside buildings, where cellular signals can be weak and pin-point GPS tracking difficult.

Kevin MacNulty, the newly-appointed managing director of Transcomm, one of the longest-established surviving mobile data specialists, certainly believes there is great potential for a dedicated data network in the logistics market. "The Transcomm network has more in-built robustness than GSM or 3G, and is better suited to time-critical operations. Our standard service level agreement guarantees 99.5 per cent network availability for all customers, and there are discounts if we don't deliver on that promise."

Transcomm is now part of the BT group, which bought it in April recognising its long-term potential within Redcare, its remote asset-tracking division, which currently relies on GSM to upload and download data remotely. "Closed data networks complement machine-to-machine communications," says MacNulty. "That is exactly the type of communication that occurs with many delivery fleets."

Transcomm's dedicated wireless data network uses Mobitex wireless packet switching technology, which helps optimise traffic. Up to 400 users can share a Mobitex channel without loss of spectrum efficiency. Transcomm delivers 8 Kbits of data a second over a single 12.5 kHz channel.

"Theoretically GPRS data transfer speeds are faster," admits MacNulty, "but speeds drop exponentially depending on how many users there are on a channel. As more data-rich applications are marketed, there will be increasing data traffic on the GPRS networks"

GPRS circuit-switching technology requires an end-to-end connection for each call and a dedicated line while the transfer is taking place. "GPRS is called always-on, but it still requires the terminal to establish a communications link. Links can be dropped during roaming between cells, so the call has to be set up again and data retransmitted. With Transcomm, there is no degradation of service, so maximum data rates are always achieved."

Transcomm provides a clear audit trail for all message transmissions. Messages are either delivered to the intended recipient, or the sender is informed that the message was undeliverable or placed in the network mailbox. This stores any messages sent to a mobile device that is temporarily out of contact with the network, and then automatically forwards them when the mobile device re-establishes contact. Messages do not get lost, says MacNulty, and recipients never need to dial in to see if a message is waiting for them.

Native radio protocols ensure that detection and decoding of messages are virtually impossible, enhancing security. Another boost to security is the fact that Transcomm network users can only transmit to and receive data from other users within their nominated and secure closed user group (CUG). That means each company effectively has a virtual private network. Unlike GSM/GPRS, terminals do not use IP addresses, which are a known target for hackers, points out MacNulty.

Siemens Datatrak is probably the best-known company in the logistics sector for using radio technology for vehicle tracking and data transmission. Datatrak uses a dedicated data network combined with vehicle tracking, and is unique in combining two parallel radio technologies: land-based low-frequency radio transmitters for tracking, and a UHF communication network for transmitting real-time data.

UHF base stations, located at 40 to 50km intervals, provide two-way mobile radio data coverage. Messages up to 1,960 bits can be transmitted, and the TWD (Two-Way Data) service, as the name suggests, provides two-way data transmission and confirmation of message receipt in both directions.

At the same time 14 LF transmitters send time-based signals sequentially over the 130 to 170MHz spectrum. An on-board receiver uses the signals to compute its distance from each of the transmitters, automatically sending a data message reporting its current status.

Simon Drummond, sales and marketing manager, says although the technology may not have the cutting-edge appeal of GPRS or 3G, the fact that the technology is simpler than GPRS or cell-phone communications is actually a benefit for logistics companies. "Datatrak, of course, was developed by Securicor for cash-in-transit operations. Few journeys are more mission-critical than that, so there is built-in redundancy and reliability in the system. Each of the 25,000 vehicles in the UK on the Datatrak network has its own time slot on the network, and transmits is position automatically every two minutes. That's real-time communication."

Drummond says real-time vehicle location is the key. "Our view is that without real-time tracking you are trying to manage your fleet blindfolded. You would not attempt it with office employees, so why try to do it with your mobile workforce?"

Over the past few years, Datatrak's parent Siemens has added management tools to the core technology to enhance its appeal. Operators can monitor delivery schedule progress using "watchboxes" - event-driven alarms which can be geographical or time-based. If a vehicle has not appeared in the area within a designated period, or if not left the area within a defined period, a message is sent to the control centre. The Multicomms Locator switches automatically to GPS-GSM should a vehicle leave a Datatrak radio-controlled area, and for service organisations there are integrated roaming facilities on TETRA networks.

Another proprietary system using its own radio network for tracking is the one operated by QuikTrak, the Australian RF-based vehicle tracking and communications specialist. This was launched in Britain two years ago, and counts courier Addison Lee among its customers. It uses spread-spectrum technology, in which the tracking is handled remotely, rather than on board the vehicles in question.

However, the company has had to cut back on ambitious early growth plans. It says the high level of fees it has to pay for its national UK telecommunications licences has been a problem - especially since it only operates within the bounds of the M25 motorway. It is now hoping to establish relationships with third-party partners, who would market the network while it provided the technology backup.

Another company using a dedicated radio network for fleet tracking is Goole-based Fleetcomm, which says it is now the sole remaining provider of a two-way radio network with national coverage. "Key factors for many of our customers are the vehicle location capability and fixed costs," says business development director Paul Wilson.

Fleetcomm's analogue FleetTrac system links a 12-channel GPS receiver with a vehicle-mounted radio terminal. Location data is sent via the radio network to an office management terminal, where the data is displayed on a Microsoft MapPoint map. A location transmission is sent every 10 minutes as standard, although the operator can also poll any of the radio units.

Once the data is on the office system, FleetTrac provides the usual management functions and reports, including route planning and geofencing. The radios can also be programmed to send advice that an event has taken place, such as ignition off, or to report unauthorised movements.

Fleetcomm's fixed charges are £40 per vehicle per month for base-to-mobile connections. Adding the capability for drivers to talk to each other rather than via base costs another £5 per mobile unit per month. Monthly lease price for the FleetTrac management system, including PC, software and data and radio modems is £125.

Managing data over GPRS

If integrating voice communications with data is a must, a GPRS managed data service could be the solution. Cognito migrated its service from a proprietary radio network to GPRS two years ago, believing that integration of voice and data communications offered customers greater flexibility than a data-only network. Its Formsplus mobile data application suite manages voice and data calls between mobile users and based.

"We can provide a real solution for organisations that need to take advantage of mobile data technology, but want to avoid the risks of uncontrollable assets in the field and the integration, management and support headaches," says managing director Steve Alderson. "Through enhancements such as event time stamping, data exchange audit trails and individual user rights management, Formsplus is now providing organisations with a much higher degree of control, flexibility and productivity."

A new version of the Formsplus mobile data application suite has just been released, incorporating recognition of service level agreements, digital signature capture and easier navigation. Mobile workers can log straight into their job allocation system via a PDA, review new jobs, plan their route and process jobs.

Handset applications can now be updated remotely over the network, and an enhanced reporting function means managers have up-to-date reports on mobile activity.

TETRA

TETRA was conceived as a European public digital radio standard for mobile communications, and a key objective was to enhance the ability of civil safety organisations such as fire, police and ambulance services and local authorities to communicate with each other in an emergency.

It uses less of the radio spectrum than other digital technologies, enabling it to carry voice and data simultaneously, and a core objective was it should remain operational in a civil emergency. Network operators have to provide coverage guarantees, so there is inbuilt robustness such as back-up generator power for occasions when normal power lines might fail.

A single TETRA transmitter covers a 10km radius, compared with 200 to 300 metres for 802.11b networks and some GSM transmitters.

TETRA strayed into the UK's commercial market a few years ago, when it was promoted as the new digital standard for the country's many public access mobile radio users. A company called Dolphin was set up to market the service as the successor to NB3, a key player in the previous Band Three analogue PAMR market, with backing from US-based Qualcomm.

However, Dolphin struggled to maintain market share against the rising tide of opposition from other forms of communication, and this summer the network was finally shut down.

So TETRA's main UK support is now confined to specialised user groups in the emergency service market. However, it seems to be finding a lively if sometimes uneven welcome there, and its arrival has prompted the development of a new generation of compatible Java-enabled mobile radios - with all the application development benefits associated with Java.

"We have developed more new PMR radios in the last three years than in the previous ten," says Jeppe Jepsen, director of international business relations for Motorola. Jepsen believes the combination of TETRA and Java-embedded technology in the latest MTH handsets has helped attract the 35 application partners who currently belong to its Motorola developers club.

The latest MTH handsets can incorporate GSM handset technology such as high-resolution colour screen, GPS receivers for exact positioning, and cameras. The colour screens mean officers should in theory be able to send and receive clear images of criminals and missing persons, along with maps to help them locate premises.

The new radios also help with resource planning at police stations. An officer's location can be accurately plotted by control room staff in order to get a better idea of overall resource deployment.

Motorola has also won contracts with the Metropolitan Police for 30,000 MTH650 radios, while Scottish police forces are buying 18,000 of the more sophisticated MTH800 with integrated GPS.

Nokia's THR850 handset is typical of the new generation TETRA radios. At 196 grams, its weight is only a third that of previous models, and it has more functionality. Li-ion batteries have increased standby time threefold to between 20 and 30 hours, with talk time ranging up to four and a half hours.

Jepsen also sees future potential for local-authority run TETRA networks and for communications on public transport systems, primarily for data such as vehicle location, passenger numbers and fuel consumption, with voice capability a bonus in the event of an emergency.

"The transmitter can be used not just by the council itself, but also by commercial organisations in the area. We have already deployed it at airports, for example, where the airport buys the network and airlines pay to access it for ground voice and data communications."

TETRA is also being targeted for military applications, including peacekeeping missions where reliable communications are essential. Motorola is already working with NATO, and has a base station established in Basra, in Iraq. This transmits data to a military satellite, which then relays it back to the UK.

O2 Airwave - new standards for emergency services

The UK's best-known TETRA network is now O2 Airwave. Based on Motorola technology, it is a secure digital radio network for the exclusive use of emergency and public safety services. Airwave is part of the Government's Critical National Infrastructure. The service is being provided to all police forces throughout England, Scotland and Wales as part of a £2.9 billion UK Government contract. O2 Airwave will be fully rolled out by mid-2005, by which time the current total of 50,000 users will have doubled to 100,000.

Airwave was originally intended primarily as a robust voice network, which would also provide data access to the Police National Computer. Thirty-nine out of fifty-one police forces in the UK are already using it. Police officers can access the Police National Computer over the secure Airwave network, which can save valuable time in establishing, for example, a number plate check on a suspicious car. An officer can received the details on his handset in 7 seconds, says O2.

O2's experience is that while police operations are very voice-oriented, other emergency services are equally attracted by the data capabilities of TETRA. Paramedics, for example, can transmit patient details and current condition while en route to the nearest hospital, and then get a voice call back helping with diagnosis.