Stable Modulation Index Calibration and Dynamic Control

A system for wireless communications with Gaussian frequency-shift keying (GFSK), the system comprising:

• a signal generator configured to generate training bit sequences;
• a pulse shaping element configured to generate shaped signals from the training bit sequences and a modulation index value;
• a baseband transmitter configured to generate transmission signals from the shaped signals;
• a frequency deviation estimator configured to determine frequency deviations of the transmission signals;
• and
• a modulation index value estimator configured at least to:
• in a first iteration, determine a first updated modulation index value based on a first frequency deviation and update the modulation index value used by the pulse shaping element;
• and
• in a second iteration, determine a second updated modulation index value based on a second frequency deviation and update the modulation index value used by the pulse shaping element.

A method for modulation index calibration in a wireless communication system with Gaussian frequency-shift keying (GFSK), the method comprising:

• generating training bit sequences;
• generating shaped signals from the training bit sequences and a modulation index value;
• generating transmission signals from the shaped signals;
• determining frequency deviations of the transmission signals;
• in a first iteration, determining a first updated modulation index value based on a first frequency deviation and updating the modulation index value;
• and
• in a second iteration, determining a second updated modulation index value based on a second frequency deviation and updating the modulation index value.