Doppler compensation for OFDM transmission by sectorised 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 intercarrier-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 timeor frequency-domain. Our 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 omnidirectional antenna. This not only eases channel estimation but also allows for a diversity gain due to maximum-ratio-combining. We will demonstrate that our scheme copes well with large maximum Doppler frequencies.