Directive antenna diversity reception for an adaptive modulation system in land mobile communications

The Letter proposes a directive antenna diversity reception scheme for an adaptive modulation /TDMA/TDD system to achieve high quality, high bit rate and high spectral efficient data transmission even in high mobility land mobile communication environments. In mobile stations, a directive antenna diversity is applied to reduce the Doppler spread equally in each branch. At each branch, the offset frequency (f_off ) and f_off-cancelled fading variation are estimated to improve the accuracy of the propagation path characteristic estimation even in high maximum Doppler frequency (f_d) environments. Computer simulation confirms that the proposed scheme can achieve successful variable rate transmission in fast fading environments