Decision-directed compensation of modulation-index drift for high bit rate equalized GMSK radio LANs

For an equalized Gaussian minimum shift keying system, the modulation-index drift from 0.5 associated with a simple direct FM implementation may result in a severe degradation on the equalizer performance. A decision-directed compensation for the drift is proposed. Computer simulations show that a large part of the performance loss due to modulation-index drift can be recovered with the proposed method.