Doppler-Compensation for OFDM Transmission by Sectorized Antenna Reception
Rapidly time-varying channels are a major obstacle for successful data-transmission via OFDM. The resulting loss of orthogonality among neighboring subcarriers leads to inter-carrier-interference, which affects channel estimation. This in turn impedes the subsequent data detection. Literature contains numerous approaches to cope with this problem working either in time- or frequency-domain. The authors' concern in this paper is a novel time-domain method which relies on the use of multiple directional receive antennas. Each of these antennas experiences only a fraction of the total Doppler spread of a comparable omni-directional antenna. This not only eases channel estimation but also allows for a diversity gain due to maximum-ratio-combining.