Performance of space-time-coded OFDM with sectorized antenna reception

Abstract

Diversity is a well-known means to counter the detrimental effect of fading. Against this background, space-time codes have been designed to facilitate transmit diversity with a suitable receiver. Furthermore, space-time codes combined with OFDM allow for the utilization of frequency selective channels. However, a general assumption underlying the design of space-time codes is the time-invariance of the channel, which is violated in a high mobility environment. Large Doppler spread causing rapidly time-varying channels can be compensated at the receiver by sectorized antennas, which restrict the angle of incidence of imping waves to a finite range. Compared to an omnidirectional antenna, the resulting Doppler spread of a sector antenna and the channels time-variance are reduced. In this paper, we demonstrate the benefits of Doppler compensating sectorized antennas for space-time coded OFDM.