TIBWB-OFDM: A Promising Modulation Technique for MIMO 5G Transmissions

Time-Interleaved Block Windowed Burst-OFDM (TIBWB-OFDM) was recently proposed as a new waveform candidate for future 5G systems and beyond. In this paper, it is shown that this technique is, in fact, easily combined with MIMO systems, offering promising gains in terms of power and spectral efficiency. In addition, since TIBWB-OFDM is built on the mature OFDM technique, it enables fast forward implementation of a frequency domain equalization with inter-stream MIMO suppression, maintaining the simplicity of the equalizer at an affordable cost. Bearing the complexity requirement in mind, three equalization techniques are studied, namely low-complexity iterative maximum rate combining (MRC) and equal gain combining (EGC) receivers, that do not require costly matrix operations, and an iterative block decision feedback equalizer (IB-DFE) receiver that, although requiring matrix inversions, can provide excellent results by taking advantage of single-carrier type nature of the TIBWB-OFDM block. We show that, on the one hand, IB-DFE receiver exhibits superior gains and can be successfully employed in scenarios with moderate number of antenna-elements, where its complexity can be actually manageable. On the other hand, it is shown that iterative MRC and EGC offers excellent performances for high values of receiving antenna-elements.