Antenna Selection for NoncoherentSpace-Time-Frequency Coded OFDM Systems

摘要

This paper studies receiver antenna selection (AS)rnfor multi-antenna systems operating over frequency selectivernchannels, where the channel state information (CSI) is neitherrnknown at the transmitter nor at the receiver. We consider ASrnfor noncoherent space-time-frequency (STF) coded orthogonalrnfrequency division multiplexing (OFDM) systems that employrnunitary signals. An OFDM receiver with a single RF chain isrnemployed, and the selection is based on the received signal power,rnwhere the receive antenna with the largest received signal powerrnaveraged over all subcarriers is chosen. Theoretical analysisrnand simulations show that using AS, the maximum spatial andrnmultipath diversity can still be obtained without CSI at thernreceiver, the same as the full-complexity multi-antenna OFDMrnsystems. We simplify code design and decoding using subcarrierrngrouping, which enables us to apply existing full diversity codesrnfor noncoherent STF-OFDM systems to each group, in orderrnto obtain maximum spatial and multipath diversity when AS isrnused. We also present a low-complexity suboptimal decoder thatrnachieves full diversity and can be easily implemented in practice.