Trunked radio net uses software

Axell Wireless has launched what is believed to be the world's first terrestrial trunked radio (TETRA) digital repeater based on software defined radio (SDR) technology.

The CSR438 digital channel selective repeater will provide quick and secure radio coverage in any TETRA network and can be used to expand a base station's service area by filling in coverage gaps caused by terrain, buildings or tunnels, or simply extending coverage into rural or remote areas.

SDR is a collection of hardware and software technologies that enables reconfigurable system architectures for wireless communications. Traditional hardware-based radio devices limit cross-functionality and can only be modified through physical intervention.

SDR enables new wireless features and capabilities to be added to existing radio systems through software upgrades rather than a hardware upgrade.

The CSR438 is a further extension of the company's existing next-generation products based on SDR and can be upgraded and optimised with the minimum of service interruption as new TETRA network developments emerge.

The system is claimed to be the first TETRA product to offer low delay and high selectivity filter configuration parameters and alarm monitoring within the same hardware.

This means that service providers can configure the repeater between either low delay (for example, rural areas with little radio interference) or high selectivity filter parameters (for example, urban areas with a great deal of RF 'noise') to ensure the most effective signal delivery, rather than traditionally buying separate pieces of equipment.

It also offers a new way to provide rural or remote TETRA coverage through using frequency shifting technology.

It enables networks to be deployed more cost effectively by lowering the number of base stations required to achieve a stated level of coverage.

Frequency shifting can extend TETRA base station coverage by up to 57 km from the base site, the actual distance limit within a TETRA system.

The system also offers a large coverage footprint and supports up to eight TETRA carriers with a 16-channel version available in the future.