In this paper, a new space-time signaling scheme is proposed for Orthogonal Frequency Division Multiplexing
(OFDM) using complementary sequences derived from the rows of the DFT matrix. The autocorrelative properties
of the complementary sequences allows multiple complex data signals at the transmitter with an arbitrary
number of antennas to be perfectly separated and reconstructed at the receiver without prior channel knowledge
while achieving full-rate. This new method is proposed and derived for multiple MIMO-OFDM systems with
multipath fading; at the receiver, symbol estimation is effected via maximum likelihood estimation (ML).
Proc. SPIE. 7349, Wireless Sensing and Processing IV
KEYWORDS: Signal to noise ratio, Transmitters, Modulation, Interference (communication), Receivers, Telecommunications, Signal processing, Antennas, Orthogonal frequency division multiplexing, Binary data
In this paper, a new method of space-time processing is proposed for Orthogonal Frequency Division Multiplexing
(OFDM) using complementary pairs of Golay sequences. Space-time processing with complementary Golay
sequences provides diversity at the transmitter which in turn helps improve performance in multipath fading
channels without the need for channel knowledge at the transmitter. The autocorrelative properties of complementary
Golay pairs allows multiple data signals at the transmitter to be perfectly separated at the receiver.
Further, these properties significantly boost the signal energy at the receiver, leading to a higher SNR and thus
better bit error performance. Building on work done in the field of orthogonal space-time block codes, the new
Golay method is proposed and derived for both a 2×1 and 2×2 MIMO-OFDM system with a channel exhibiting
Rayleigh fading; at the receiver, symbol estimation is effected via minimum mean-square estimation (MMSE).
In this paper, an interference cancellation and equalization method is proposed for a multiple-input, multipleoutput
orthogonal frequency division multiplexing (MIMO-OFDM) system. Standard equalization techniques
such as zero-forcing (ZF) and adaptive array processing techniques such as per-tone or time-domain equalization
may require large amounts of training and memory for storage of the weight coefficients. In a MIMO-OFDM
system with <i>N</i> carriers, equalizers at each antenna are characterized by the solution space associated with an
underdetermined system of linear equations. A structured per-tone technique is proposed that utilizes the extra
degrees of freedom in order to cancel interfering signals; the resultant equalizers (weight vectors) have lengths
significantly smaller than N, but at least as long as the channel impulse response.