Tracking Sparse mmWave Channel: Performance Analysis under Intra-Cluster Angular Spread

TL;DR

This paper analyzes the limits of tracking accuracy in sparse mmWave channels considering intra-cluster angular spreads, providing theoretical insights and practical verification for beamforming performance.

Contribution

It introduces a performance bound analysis for mmWave channel tracking that accounts for intra-cluster angular spreads, which are often neglected in existing models.

Findings

Performance bounds depend on intra-cluster angular spread.

Optimal beam-width guidelines are derived for different spreads.

Verification with sector beam and maximum likelihood tracking algorithms.

Abstract

Millimeter-wave (mmWave) systems require a large number of antennas at both base station and user equipment for a desirable link budget. Due to time varying channel under user mobility, up-to-date channel state information (CSI) is critical to obtain the required beamforming gain.. The mmWave sparse multipath channel is commonly exploited in designing tracking algorithms but practical angular spread is often overlooked. In this work, we study the performance bound of tracking accuracy in sparse mmWave channel that includes intra-cluster angular spreads. Power gain from angle-steering-based beamforming using tracked CSI is then analyzed. The theoretical study provides a design guideline beam-width in angle-steering under different intra-cluster angular spreads. We verify the results with two common tracking algorithms including sector beam tracking and maximum likelihood channel tracking.