Low complexity GSM modulator for integrated circuit implementations

Reduced complexity Integrated Circuit (IC) design architecture for constant envelope modulation is presented. This method is demonstrated on the globally standardized Gaussian Minimum Shift Keying (GMSK) for the "Global System for Mobile Communications" (GSM). The in-phase and quadrature signals are generated directly from the input binary data, bypassing the separate steps of integrating, and then calculating the sine and cosine values. The implementation takes advantage of waveform symmetry properties thereby leading to reduction in memory requirements by 800% with respect to full storage of required waveforms. Performance comparison with a commercially available GSM IC is also carried out.