Custom DSP Design of a GSM Speech Coder

The GSM speech coder for digital mobile telephones has been designed on a custom DSP using an environment for development of arbitrary processor architectures. A netlist of the speech coder has been generated from a high level description in a presented design environment. Improvement of the performance both by modifying the high level description and by hand optimization of the microcode is discussed. Advantages of a user interactive system were stepwise refinement leads to a competitive result is thus demonstrated. Simulation has been performed at algorithm, microcode, and transistor level for consistency check. To avoid dependency of a specific vendor the design environment allows implementation in various technologies and a netlist for a Plessey gate array has been generated as an example