Next Article in Journal
Research on Lifespan Prediction of Composite Insulators in a High Altitude Area Experimental Station
Previous Article in Journal
Automatic Zebrafish Egg Phenotype Recognition from Bright-Field Microscopic Images Using Deep Convolutional Neural Network
Open AccessArticle

Multiuser Equalizer for Hybrid Massive MIMO mmWave CE-OFDM Systems

Instituto de Telecomunicações (IT) and Departamento de Eletrónica, Telecomunicações e Informática (DETI), University of Aveiro, 3810-193 Aveiro, Portugal
Instituto de Telecomunicações (IT) and Faculdade de Ciências e Tecnologia, University Nova de Lisboa, 1099-085 Lisboa, Portugal
Author to whom correspondence should be addressed.
Appl. Sci. 2019, 9(16), 3363;
Received: 5 July 2019 / Revised: 8 August 2019 / Accepted: 13 August 2019 / Published: 15 August 2019
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
This paper considers a multiuser broadband uplink massive multiple input multiple output (MIMO) millimeter-wave (mmWave) system. The constant envelope orthogonal frequency division multiplexing (CE-OFDM) is adopted as a modulation technique to allow an efficient power amplification, fundamental for mmWave based systems. Furthermore, a hybrid architecture is considered at the user terminals (UTs) and base station (BS) to reduce the high cost and power consumption required by a full-digital architecture, which has a radio frequency (RF) chain per antenna. Both the design of the UT’s precoder and base station equalizer are considered in this work. With the aim of maximizing the beamforming gain between each UT and the BS, the precoder analog coefficients are computed as a function of the average angles of departure (AoD), which are assumed to be known at the UTs. At the BS, the analog part is derived by assuming a system with no multi-user interference. Then, a per carrier basis nonlinear/iterative multi-user equalizer, based on the iterative block decision feedback equalization (IB-DFE) principle is designed, to explicitly remove both the multi-user and residual inter carrier interferences, not tackled in the analog part. The equalizer design metric is the sum of the mean square error (MSE) of all subcarriers, whose minimization is shown to be equivalent to the minimization of a weighted error between the hybrid and the full digital equalizer matrices. The results show that the proposed hybrid multi-user equalizer has a performance close to the fully digital counterpart. View Full-Text
Keywords: CE-OFDM; hybrid analog/digital architectures; massive MIMO; mmWave communications; nonlinear equalizer CE-OFDM; hybrid analog/digital architectures; massive MIMO; mmWave communications; nonlinear equalizer
Show Figures

Figure 1

MDPI and ACS Style

Magueta, R.; Teodoro, S.; Castanheira, D.; Silva, A.; Dinis, R.; Gameiro, A. Multiuser Equalizer for Hybrid Massive MIMO mmWave CE-OFDM Systems. Appl. Sci. 2019, 9, 3363.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map

Back to TopTop