Field trial on adaptive modulation of microwave communication link at 6.8GHz

The results of a field trial conducted in Switzerland between September 2011 and June 2012 are presented. The goal of the trial was to investigate the benefit of adaptive modulation in a channel with strong frequency selective fading. It is found that the availability of the system using adaptive modulation follows the predictions of the ITU-R recommendations for a frequency selective channel. With similar availability (around 99.999%) the average spectral efficiency when using adaptive modulation was increased by 27.3% compared to if a fixed modulation (64QAM) had been used.