"We developed a complete model of the TETRA physical layer using Simulink. As the core of our development efforts, this model enables us to test out new ideas, analyze problems, and accelerate the pace of development."
Martin Popple, Sepura
Around the world, police, fire, ambulance, military, and other public safety organizations that depend on mobile communications in emergencies use TErrestrial Trunked RAdio (TETRA) equipment. Released in 1995 as a European Telecommunications Standards Institute (ETSI) standard, TETRA is noted for its security, reliability, short call-set-up times, and range.
As an industry leader in TETRA technology and radios, Sepura Ltd. supplies more than 600 organizations in more than 80 countries. Using Simulink and other MathWorks tools, Sepura built a complete model of the TETRA physical layer, which they use to develop TETRA radio technology and products, as well as to support TETRA Release 2 ETSI standardization.
"The Simulink model of the TETRA physical layer is central to our development efforts," says Martin Popple, Senior Software Engineer at Sepura. "We use it to rapidly test our algorithms in a simulation environment. This approach lets us try new ideas and identify problems early on rather than delaying debugging and verification until the system is implemented in the hardware."
To keep pace with market demands for TETRA technology, Sepura must respond rapidly to customer needs and play an active role in TETRA standards development. Sepura engineers needed a design and development environment that would enable them to simulate and verify new algorithms and propose standard changes before implementing them in hardware. The team also needed an efficient way to identify and diagnose performance problems.
In the past, Sepura engineers used disparate tools for simulation and data analysis, which added extra data formatting and translation steps each time they processed simulation results. The group wanted a single, integrated development environment for modeling, simulation, and post-processing.
Using Simulink, MATLAB, and companion products, Sepura engineers developed a complete model of the TETRA physical layer. The model provides a foundation for the design and development of new products, as well as for the analysis of proposed standards.
The engineers based the model on an existing set of C code libraries. They used Simulink S-functions to incorporate their C modules into the model as blocks.
Once they had built a complete model, they simulated the transmission and reception of data across a TETRA network. They used MATLAB to post-process the simulation results and verify the correct operation of the model.
Sepura engineers used this baseline model to diagnose anomalies and resolve problem reports. Engineers recorded burst data from actual hardware, imported the data into Simulink, simulated the burst decoding process, and analyzed the results in MATLAB. "With Simulink we could identify right away whether the problem was with the burst itself or with the decoding algorithms," says Dr. Popple. Sepura engineers used DSP System Toolbox™ and Communications System Toolbox™ to develop new algorithms for implementing TETRA's π/4 differential quadrature phase shift keying (π/4 DQPSK) modulation scheme. They used blocks for coding, interleaving, modulation, convolution, filtering, synchronization, decoding, and other operations.
After debugging the new algorithms in this reference model with Simulink, the team replaced blocks from DSP System Toolbox and Communications System Toolbox with S-functions written in C.
They compared simulation results from this model with results from the reference model to verify the C code, an approach that expedited the process of implementing the system on Sepura's proprietary hardware.
Sepura is currently using the physical layer model and Simulink to support the ETSI TETRA Release 2 standardization process by verifying proposed standards through simulation.
Since 2003, SEPURA has used MATLAB and Simulink in the development of its leading handset products, including the SRH3000 family.
To accelerate the development of TETRA-based mobile communication technology
Use MathWorks tools to build, simulate, and verify a complete model of the TETRA physical layer