Machine Learning Prediction for Phase-less Millimeter-Wave Beam Tracking

TL;DR

This paper proposes an LSTM-based beam tracking algorithm for millimeter-wave communications that uses phase-less measurements, achieving accurate beam alignment with fewer measurements and improved scalability under hardware impairments.

Contribution

Introduces a novel LSTM-assisted beam tracking method that operates with phase-less measurements, enhancing efficiency and robustness compared to existing approaches.

Findings

Achieves comparable beam alignment accuracy to state-of-the-art methods.

Reduces the average number of measurements needed for beam tracking.

Demonstrates robustness under hardware impairments.

Abstract

Future wireless networks may operate at millimeter-wave (mmW) and sub-terahertz (sub-THz) frequencies to enable high data rate requirements. While large antenna arrays are critical for reliable communications at mmW and sub-THz bands, these antenna arrays would also mandate efficient and scalable initial beam alignment and link maintenance algorithms for mobile devices. Low-power phased-array architectures and phase-less power measurements due to high frequency oscillator phase noise pose additional challenges for practical beam tracking algorithms. Traditional beam tracking protocols require exhaustive sweeps of all possible beam directions and scale poorly with high mobility and large arrays. Compressive sensing and machine learning designs have been proposed to improve measurement scaling with array size but commonly degrade under hardware impairments or require raw samples respectively. In this work, we introduce a novel long short-term memory (LSTM) network assisted beam tracking and prediction algorithm utilizing only phase-less measurements from fixed compressive codebooks. We demonstrate comparable beam alignment accuracy to state-of-the-art phase-less beam alignment algorithms, while reducing the average number of required measurements over time.