Linear detection schemes for MIMO UW-OFDM

A new signaling concept, known as unique word - orthogonal frequency division multiplexing (UW-OFDM), has been introduced recently. It has been shown that UW-OFDM has better spectral properties and also a superior bit error ratio (BER) performance over conventional cyclic prefix (CP) based OFDM. In UW-OFDM, the CPs are replaced by deterministic sequences, the so-called unique words (UWs). This is achieved by adding redundancy in the frequency domain with the help of a code generator matrix at the transmitter which introduces correlation between the data symbols. A superior BER performance is achieved if the code generator matrix is utilized efficiently in the detection procedure. In wireless communication systems multiple-input multiple-output (MIMO) techniques are widely used to improve the overall spectral and energy efficiency by exploiting the multiple antennas. So far, the performance of UW-OFDM has been well investigated for single-input single-output (SISO) systems. In this work, we expand our investigation of UW-OFDM to MIMO systems and propose two detection approaches. We show that similar to CP-OFDM, a subcarrier wise detection is also possible for UW-OFDM. But in addition an efficient code generator demodulator is required to take advantage of the correlation introduced in the data symbols. The results show that UW-OFDM outperforms CP-OFDM significantly but requires a higher computational complexity.