To meet this need, TETRA Ireland has been testing a innovative class of TETRA device, a radio pager. These pocket-sized two-way messaging devices are expected to become available on the network in the coming months.
Mr Kelly believes that the excellent coverage of the Irish network will make pagers a useful tool and a communications lifeline for those users who do not need voice contact. The units will transmit and receive SDS (TETRA Short Data Service) messages, and will have an emergency button which will send the user’s GPS coordinates to the control room. The control room will then be able to provide appropriate escalation of response.

Mr Kelly foresees plenty of growth for TETRA in this area for the future. “The new solution is much more than your traditional pager”, he says. “This will be a multifunctional device that will bring additional messaging capability with an added personal security assurance.”

Voice and data

For now, the NDRS is being used primarily for voice, but a standard automatic vehicle location system (AVLS) will be offered to network users soon, and then other data applications will be added, beginning – most likely – with database interrogation. These could be based on devices such as tablets and mobile PCs.

“Then we will see whether we can develop some more complex data applications with third-party providers”, Mr Kelly says. “The UK police have done crime incident reports over PDAs, which we have looked into. We want to start with data SDS applications. We will develop onwards from there.”

More advanced technologies such as TETRA TEDS wideband data are still some way off, in Mr Kelly’s view. “The difficulty about mobile data is actually to see where the drivers are coming from, from an operational perspective”, he says. “There are drivers, but it’s not a simple story and it’s not a single solution either. You have to work with your customer to see what they actually want.”

TETRA tips

TETRA Ireland’s strategy, Pat Kelly admits, was an ambitious one. But he says, “Despite concerns by some that the network could not be built and delivered in the timescale proposed, we were always confident. We leveraged the experience and knowledge of our partners Motorola, the national telecoms provider Eircom, who operate fixed and mobile communications themselves, and Sigma Communications, who have a lot of PMR experience.

What, then, would be his advice to others planning a radio project?

“First would be planning. Know your sites. The key thing is, what’s the coverage required? What is the optimum number of sites? Have alternatives to sites because if the first chosen one isn’t a feasible option, you will need a back-up.

“Good communication with the customer at the various levels is key.

“And lastly, manage supplier dealings well. Be absolutely clear with responsibilities. Clarity. Have systems that, if things are going wrong, that you are measuring the metrics to know. Planning, communication, partnership with the agencies is critical.

“The way I see this, we are building a network on behalf of the agencies. This is really their network. They set out the coverage spec of what they wanted in the network, so they were the key from the start.

“If that is right at the start, it really gives a very good foundation to build a network.”



ABOUT THE NETWORK

TETRA Ireland’s system is founded on Motorola infrastructure, with two Dimetra IP switches and two clusters per switch. In the event of failure at one switch, all the sites can be transferred to the other switch, on hot standby.
The cross-country linking network is a resilient combination of leased lines and microwave point-to-point radio links. System resilience is further improved by deliberate overlapping of coverage between base stations, which is also designed to improve in-building coverage.

“The Dublin part of the network has been operating for almost two years”, says Pat Kelly, chief executive. “We really haven’t had any service-impacting incident, and that really has impressed the users. Even when we had the snow last winter and we had storms, we had no loss of service.

“We operate an outsourced model with some network management and customer service performed by partners. We provide a 24-hour, 365 days a year network management and monitoring service, and similarly a customer service facility where we deal with all queries from our customers on an online portal.

“TETRA Ireland, being the end-to-end operator, provides the management of all the components of the service and manages all the customer interfaces.”

PLANNING THE NETWORK

Of TETRA Ireland’s 600 sites, the great majority are existing sites with only 90 new ones. “TETRA Ireland had a large database of sites, 5000”, says John Reilly, one of TETRA Ireland’s RF specialists. “And in the event a site could not be used for planning reasons or could not give the necessary coverage, another site was selected. Continually we were reviewing our sites and alternatives, and this was the key for a fast build-out of the network.”
(中國(guó)集群通信網(wǎng) | 責(zé)任編輯：陳曉亮)