University of Oulu

A. Padmanabhan and A. Tölli, "Interference Management via User Clustering in Two-Stage Precoder Design," 2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Kalamata, 2018, pp. 1-5. doi: 10.1109/SPAWC.2018.8446017

Interference management via user clustering in two-stage precoder design

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Author: Padmanabhan, Ayswarya1; Tölli, Antti1
Organizations: 1Centre for Wireless Communications (CWC), University of Oulu, Finland - FI-90014
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
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Language: English
Published: , 2018
Publish Date: 2019-01-16


We consider a single cell downlink (DL) massive multiple-input multiple-output (MIMO) set-up with user clustering based on statistical information. The problem is to design a fully digital two-stage beamforming aiming to reduce the complexity involved in the conventional MIMO processing. The fully digital two-stage beamforming consists of a slow varying channel statistics based outer beamformer (OBF) and an inner beamformer (IBF) accounting for fast channel variations. Two different methods are presented to design the OBF matrix, so as to reduce the size of effective channel used for IBF design. A group specific two-stage optimization problem with weighted sum rate maximization (WSRM) objective is formulated to find the IBF for fixed OBF. We begin by proposing centralized IBF design were the optimization is carried out for all sub group jointly with user specific inter-group interference constraints. In order to further reduce the complexity, we also propose a group specific IBF design by fixing the inter group interference to a constant or by ignoring them from the problem altogether. In spite of incurring a small loss in performance, the computational complexity can be saved to a large extent with the group specific processing. Numerical experiments are used to demonstrate the performance of various proposed schemes by comparing the total sum rate of all users and the design complexity.

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Series: SPAWC. Signal processing advances in wireless communications
ISSN: 1948-3244
ISSN-E: 1948-3252
ISSN-L: 1948-3244
ISBN: 978-1-5386-3512-4
ISBN Print: 978-1-5386-3513-1
Pages: 1 - 5
DOI: 10.1109/SPAWC.2018.8446017
Host publication: 2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)
Conference: IEEE International Workshop on Signal Processing Advances in Wireless Communications
Type of Publication: A4 Article in conference proceedings
Field of Science: 213 Electronic, automation and communications engineering, electronics
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