Title
Channel Extrapolation for FDD Massive MIMO - Procedure and Experimental Results.
Abstract
Application of massive multiple-input multiple-output (MIMO) systems to frequency division duplex (FDD) is challenging mainly due to the considerable overhead required for downlink training and feedback. Channel extrapolation, i.e., estimating the channel response at the downlink frequency band based on measurements in the disjoint uplink band, is a promising solution to overcome this bottleneck. This paper presents measurement campaigns obtained by using a wideband (350 MHz) channel sounder at 3.5 GHz composed of a calibrated 64 element antenna array, in both an anechoic chamber and outdoor environment. The Space Alternating Generalized Expectation-Maximization (SAGE) algorithm was used to extract the parameters (amplitude, delay, and angular information) of the multipath components from the attained channel data within the training (uplink) band. The channel in the downlink band is then reconstructed based on these path parameters. The performance of the extrapolated channel is evaluated in terms of mean squared error (MSE) and reduction of beamforming gain (RBG) in comparison to the ground truth, i.e., the measured channel at the downlink frequency. We find strong sensitivity to calibration errors and model mismatch, and also find that performance depends on propagation conditions: LOS performs significantly better than NLOS.
Year
DOI
Venue
2019
10.1109/VTCFall.2019.8891267
VTC-Fall
Field
DocType
Citations 
Multipath propagation,Wideband,Beamforming,Frequency band,Computer science,Antenna array,MIMO,Communication channel,Electronic engineering,Telecommunications link
Conference
0
PageRank 
References 
Authors
0.34
0
7
Name
Order
Citations
PageRank
Thomas Choi164.93
François Rottenberg211.42
Jorge Gomez-Ponce323.06
Akshay Ramesh400.34
Peng Luo511.04
Jianzhong Zhang616016.28
Andreas F. Molisach78233616.51