On the Rohde & Schwarz stand was the latest evolution of the company’s Accessnet-T TETRA infrastructure, which has now become wholly IP-based.

“Accessnet-T was already IP-based internally since the very beginning”, explained product manager Markus Oltmanns. “But we are now also using IP backbone networks in a complete IP-based environment.

“We can use existing IP-based connection lines that the customer already has. We can adapt to these networks and connect our network elements such as base stations and switching units and also gateways to the existing IP network.”

Distributed intelligence

As an alternative to the traditional central switching arrangement, Accessnet-T IP supports distributed switching intelligence within the network. This takes advantage of the self-healing capability of IP networks, which enables traffic to be re-routed around an equipment or line failure.

“Let’s say, if more than one connection line fails, you can already maintain sub-networks that are still alive until every connection line breaks – and then the single base station will go into fallback mode”, continued Mr Oltmanns. “This is already known to TETRA, specified in the standard. And as soon as the connection lines are available again, all the connections are set up... All the base stations and switching synchronize each other automatically, with a very low amount of traffic on the IP network.”

In addition, an IP architecture provides design flexibility. “You can have a gateway at one base station, and let’s say a PABX gateway at another base station and an application gateway at another base station”, Mr Oltmanns said. “So you can freely distribute all gateways and interfaces within the network as you need it.”

In addition, he added, the IP network can very easily be resized to match changing communications needs. “You can do a rapid redeployment of the network so you can take more base stations into the network, you can take base stations out of the network. There is great flexibility and means of scalability.

“You can start with a very small network when you have a small industry, and when your business grows the TETRA system will grow with your business.”