Hardware-constrained signal processing for mm-Wave LoS MIMO

Mamandipoor, Babak; Sawaby, Mahmoud; Arbabian, Amin; Madhow, Upamanyu

doi:10.1109/acssc.2015.7421379

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…Channel: For the pure LoS channel we consider, the elements of H in (3) are calculated by employing ray-tracing in consideration of the spherical nature of the wave propagation [27], [28] and the columns of H are normalized to unit norm. Since the path loss differences among different transmit-receive antenna pairs are negligible, the normalized channel matrix for the symmetric 4 × 4 LoS MIMO communication system is given by [9]…”

Section: System Model and Problem Formulationmentioning

confidence: 99%

All-Digital LoS MIMO with Low-Precision Analog-to-Digital Conversion

Sezer¹,

Madhow²

2021

Preprint

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Line-of-sight (LoS) multi-input multi-output (MIMO) systems exhibit attractive scaling properties with increase in carrier frequency: for a fixed form factor and range, the spatial degrees of freedom increase quadratically for 2D arrays, in addition to the typically linear increase in available bandwidth.In this paper, we investigate whether modern all-digital baseband signal processing architectures can be devised for such regimes, given the difficulty of analog-to-digital conversion for large bandwidths. We propose low-precision quantizer designs and accompanying spatial demultiplexing algorithms, considering 2 × 2 LoS MIMO with QPSK for analytical insight, and 4 × 4 MIMO with QPSK and 16QAM for performance evaluation. Unlike prior work, channel state information is utilized only at the receiver (i.e., transmit precoding is not employed). We investigate quantizers with regular structure whose high-SNR mutual information approaches that of an unquantized system. We prove that amplitude-phase quantization is necessary to attain this benchmark; phase-only quantization falls short. We show that quantizers based on maximizing per-antenna output entropy perform better than standard Minimum Mean Squared Quantization Error (MMSQE) quantization. For spatial demultiplexing with severely quantized observations, we introduce the novel concept of virtual quantization which, combined with linear detection, provides reliable demodulation at significantly reduced complexity compared to maximum likelihood detection.

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Section: System Model and Problem Formulationmentioning

confidence: 99%

All-Digital LoS MIMO with Low-Precision Analog-to-Digital Conversion

Sezer¹,

Madhow²

2021

Preprint

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“…Previous works determined that the MIMO technique can be applied in a LoS environment if the transmitting and receiving antennas are properly placed and separated . Various techniques for LoS MIMO communications, such as their applications , , performance improvements , , analyses , and receiver architectures , have also been studied. In , outdoor measurement results indicated that channel phase is affected by abnormal atmospheric variations.…”

Section: Introductionmentioning

confidence: 99%

“…In , outdoor measurement results indicated that channel phase is affected by abnormal atmospheric variations. Analog and digital alignment mismatch compensation techniques were proposed in and respectively. However, their performance was evaluated through simulations.…”

Section: Introductionmentioning

confidence: 99%

16-QAM OFDM-Based K-Band LoS MIMO Communication System with Alignment Mismatch Compensation

Kim¹,

Kim²,

Kang³

et al. 2017

ETRI Journal

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This paper presents a novel K-band (18 GHz) 16-quadrature amplitude modulation (16-QAM) orthogonal frequency-division multiplexing (OFDM)-based 2 3 2 line-of-sight multi-input multi-output communication system. The system can deliver 356 Mbps on a 56 MHz channel. Alignment mismatches, such as amplitude and/or phase mismatches, between the transmitter and receiver antennas were examined through hardware experiments. Hardware experimental results revealed that amplitude mismatch is related to antenna size, antenna beam width, and link distance. The proposed system employs an alignment mismatch compensation method. The openloop architecture of the proposed compensation method is simple and enables facile construction of communication systems. In a digital modem, 16-QAM OFDM with a 512-point fast Fourier transform and (255, 239) Reed-Solomon forward error correction codecs is used. Experimental results show that a bit error rate of 10 À5 is achieved at a signal-to-noise ratio of approximately 18.0 dB.

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