Estimating velocity using diversity reception

In mobile communication systems, the velocity of mobile terminals is important for adequate handoff control and efficient dynamic channel assignment. We can estimate the velocity of a mobile terminal in a Rayleigh fading channel, because it is proportional to the Doppler frequency. Diversity reception is the most common method of improving communication quality in faded channels, and since the switching rate of diversity branches is proportional to the Doppler frequency, the velocity is easily estimated. We derived a relationship between the switching rate of the branches N_BS (times/s), and the Doppler frequency f_D (Hz): as follows N_BS≃1.3 f_D . We confirmed this relationship experimentally, and since our method is very simple and needs no additional equipment, it can easily be implemented in mobile terminals