Cost-effective implementation of TETRA codec using the primitive functions of the compiler

The TETRA (terrestrial trunked radio) speech codec is mandatory for all TETRA mobiles and networks. This paper presents the cost-effective implementation of the TETRA speech codec using the primitive functions of the compiler for the 16 bit fixed-point eDSP (embedded DSP), which was developed by ETRI for the purpose of use in various SoCs. Generally, the simple implementation of the speech codec is using the cross compiling but it probably does not operate in real-time. The more optimized implementation is the fully hand-written assembly code but this approach is very time consuming compared to the cross compiling methods. More efficient way is using the cross compiling with the primitive functions. In this way, we convert the basic arithmetic function in TETRA speech codec into the compact one using primitive functions of the compiler in order to reduce the computation where we used the in-house compiler of the eDSP. Employing the primitive functions makes it possible to obtain the optimized assembly code because our compiler is fully customized to the eDSP. The number of cycles can be reduced into the 8 % of the complexity of the simple cross compiling version. We also describe the comparison among some implementation approaches and their results.