Efficient Near Field Beam Tracking via Thompson Sampling

TL;DR

This paper introduces a pilot-free beam tracking method using Thompson sampling for near field scenarios, improving spectral efficiency and maintaining reliable connectivity.

Contribution

It proposes a novel beam tracking framework that models user trajectories with polynomials and adaptively probes uncertain regions without dedicated pilots.

Findings

Maintains reliable connectivity with no dedicated pilot overhead.

Uses Thompson sampling to adaptively probe uncertain trajectory regions.

Outperforms conventional methods in spectral efficiency and connection reliability.

Abstract

The shift to the radiative near field region due to large antenna arrays necessitates beamforming that accounts for both angle and range, evolving mobility management into a joint angular range tracking challenge. Conventional schemes rely on rigid pilot payload structures with dedicated training slots, which interrupt data transmission and degrade spectral efficiency. To address this, we propose a pilot-free beam tracking framework leveraging Thompson sampling(TS). Within each sliding window, the user trajectory is modeled by local low-order polynomials in angle and range, and the motion parameters are estimated by maximum likelihood with uncertainty quantified via the Fisher information matrix. TS adaptively probes uncertain trajectory regions using beams that simultaneously serve as payload beams. Simulations demonstrate that the proposed framework maintains reliable connectivity while eliminating the overhead of dedicated pilot-based beam sweeping.