TETRA Project Examples

TETRA Base Station Controller

This project involved:

• VxWorks RTOS
• Use of DOORS requirement capture tool
• DSP CELP transcoding
• G703, UDP/IP and X21 protocols

This project was for a major player in the TETRA market. The work involved creating a 48-channel transcoder subsystem to handle conversion and routing of user-plane CELP compressed audio and control-plane data. The unit was responsible for interfacing a central switching unit with several base-stations using UDP/IP across X21 links; the number of base-stations could be expanded simply by adding more cards to the subsystem. The CELP compressed audio was encoded/decoded using multiple Analog Devices ADSP2181 DSPs. The target hardware was a MIPS processor running the VxWorksâ„¢ real time operating system. This processor performed UDP/IP routing, proprietary stack to UDP/IP stack conversion and general control processing.

The proprietary stack to UDP/IP stack conversion interfaced a proprietary in-house protocol layer model carrying control-plane data and a G703 user-plane audio stream to UDP/IP protocols. Various SNMP management and alarm functions were also implemented to control routing of data and status reporting.

As well as the core functionality described above the following were also added:

• An SNMP agent for remote control and diagnostics
• A FLASH memory filing system for storage of the program, user and control data
• The ability to download new application software from a remote location

TETRA Optical Network Card Development System
This system provided a development and test environment for a high speed optical network interface card produced by a major TETRA systems manufacturer.The test system was based on a PC and has a Windows graphical user interface, communication with the optical network card was via the PCs PCI bus.

The system generated datagram traffic which may either be looped back internally or externally via the cards two sets of optical interfaces to provide a closed loop test environment. All registers and memeory areas within the card could be accessed and changed via the tool interface.

Raycomm are a UK based, custom software and electronics design and development service company creating bespoke electronic products, mobile device software applications, backend web server software and e-commerce database software.