Joint spectral-spatial precoders in MIMO-OFDM transmitters

• Published in: Signal processing 2020-07, Vol.172, p.107538, Article 107538
• Main Authors: Taheri, Tayebeh, Mohamad, Medhat, Nilsson, Rickard, Beek, Jaap van de
• Format: Article
• Language: English
• Subjects: MIMO-OFDM; Out-of-band emissions; Precoding; Signal Processing; Signalbehandling; Spatial interference
• ISSN: 0165-1684; 1872-7557; 1872-7557
• DOI: 10.1016/j.sigpro.2020.107538

•An extended MIMO OFDM system model.•Decomposable transmit structure of spatial-spectral MRT precoder in MIMO OFDM.•Jointly optimizing the spectral and spatial precoders in MIMO OFDM systems.•Complexity and spectral efficiency analysis of joint precoding in MIMO OFDM. This work studies the joint design of spectral precoding, to avoid spectral out-of-band power emissions, and spatial precoding, to suppress spatial multiuser interference, in MIMO-OFDM systems. In current state-of-art approaches the transmit signals are precoded using two independently designed spectral and spatial precoders. In contrast this paper proposes a joint precoding of the signal to achieve a better performance. We analyse the performance of the proposed precoder in terms of spectral characteristics, system spectral efficiency and transmitter complexity. We show in particular that, interestingly, the proposed joint maximum-ratio precoder has a simple transmitter structure of two separate and consecutive banks of spectral and spatial precoders which in fact can be designed independently, while in case of zero-forcing the off-the-shelf precoders are far from the optimal. The joint zero-forcing precoder has a coupled structure and hence, we can not decompose it.