Reliable communication based on energy spreading transform and iterative detection in MIMO-OFDM systems

The challenge of ensuring reliability for high-efficiency technology, multiple-input-multiple-output orthogonal-frequency-division-multiplexing (MIMO-OFDM), in wireless frequency-selective fading environments persists. In this article, the concept of spreading a symbol's energy is proposed as a viable solution to enhance transmission reliability for MIMO-OFDM systems. And an energy-spreading-transform (EST)-based MIMO-OFDM transceiver is developed. Following the Inverse Fast Fourier Transform (IFFT) performed by the conventional MIMO-OFDM transmitter, an orthogonal transformation called the EST is introduced. This transform spreads the energy of a symbol across the entire frequency domain and all time slots. The EST is coupled with the improved iterative detection algorithm named EST-partial decision (PD)-iterative-interference-cancellation (EST-PD-IIC) to maximize and leverage the potential diversity gain. Numerical simulation results demonstrate that the proposed scheme approaches the performance bound when signal-to-noise ratio (SNR) is about 21dB for 16-ary quadrature amplitude modulation (16-QAM). Complexity analysis illustrates that the computational complexity of the evolved EST-PD-IIC algorithm is lower than that of the famous vertically Bell laboratory layered space-time detector (V-BLAST) when the antenna array size is greater than $3\times 3$. In summary, the proposed scheme is practical for providing high-quality communication in multi-path fading environments and can even enable a reliable communication without channel encoding when Eb/N0 exceeds a threshold in 5G-Advanced.