Practical Pilot Patterns for Coherent Coded OFDM Systems using Space Time Transmit Diversity
نویسندگان
چکیده
In recent times, transmit diversity has been proposed in various forms for many different communication systems. In this paper, we shall investigate, in particular the use of space-time transmit diversity (STTD) for coded OFDM systems using space-time block coding (STBC). With such an approach the STBC receiver must use one or more adjacent pilots to obtain orthogonal channel estimates from the different transmission antennas. To improve performance therefore, we propose to use pilot patterns for the separate transmission antennas, which are orthogonal in both the frequency and time directions. In this way, STBC can be used for a wide range of different conditions, since the receiver can either use adjacent pilots in the frequency or time direction depending upon the channel.
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