Channel Estimation in Broadband Millimeter Wave MIMO Systems With Few-Bit ADCs

We develop a broadband channel estimation algorithm for millimeter wave (mmWave) multiple input multiple output (MIMO) systems with few-bit analog-to-digital converters (ADCs). Our methodology exploits the joint sparsity of the mmWave MIMO channel in the angle and delay domains. We formulate the est...

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Bibliographic Details
Published in:IEEE transactions on signal processing Vol. 66; no. 5; pp. 1141 - 1154
Main Authors: Mo, Jianhua, Schniter, Philip, Heath, Robert W.
Format: Journal Article
Language:English
Published: IEEE 01.03.2018
Subjects:
approximate message passing
Broadband antennas
Broadband communication
Channel estimation
Low resolution analog-to-digital converter
millimeter wave
MIMO
Quantization (signal)
Signal processing algorithms
Training
ISSN:1053-587X, 1941-0476
Online Access:Get full text
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Summary:We develop a broadband channel estimation algorithm for millimeter wave (mmWave) multiple input multiple output (MIMO) systems with few-bit analog-to-digital converters (ADCs). Our methodology exploits the joint sparsity of the mmWave MIMO channel in the angle and delay domains. We formulate the estimation problem as a noisy quantized compressed-sensing problem and solve it using efficient approximate message passing (AMP) algorithms. In particular, we model the angle-delay coefficients using a Bernoulli-Gaussian-mixture distribution with unknown parameters and use the expectation-maximization forms of the generalized AMP and vector AMP algorithms to simultaneously learn the distributional parameters and compute approximately minimum mean-squared error (MSE) estimates of the channel coefficients. We design a training sequence that allows fast, fast Fourier transform based implementation of these algorithms while minimizing peak-to-average power ratio at the transmitter, making our methods scale efficiently to large numbers of antenna elements and delays. We present the results of a detailed simulation study that compares our algorithms to several benchmarks. Our study investigates the effect of SNR, training length, training type, ADC resolution, and runtime on channel estimation MSE, mutual information, and achievable rate. It shows that, in a mmWave MIMO system, the methods we propose to exploit joint angle-delay sparsity allow 1-bit ADCs to perform comparably to infinite-bit ADCs at low SNR, and 4-bit ADCs to perform comparably to infinite-bit ADCs at medium SNR.
ISSN:1053-587X
1941-0476
DOI:10.1109/TSP.2017.2781644