Cruising the Spectrum: Joint Spectrum Mobility and Antenna Array Management for Mobile (cm/mm)Wave Connectivity

TL;DR

This paper proposes a joint spectrum mobility and antenna array management approach for mmWave and FR3 bands, using POMDP and PBVI algorithms to optimize beamforming in highly mobile scenarios like vehicular connectivity.

Contribution

It introduces a novel formulation of spectrum mobility as a POMDP and applies PBVI to optimize beamforming across multiple frequency bands under mobility.

Findings

The proposed policy effectively maximizes data rate in multi-band scenarios.

The approach maintains performance even with user mobility deviations.

Numerical results validate the robustness of the method.

Abstract

The large bandwidths available at millimeter wave (mmWave) FR2 bands (24-71 GHz) and the emerging FR3 bands (7-24 GHz) are essential for supporting high data rates. Highly directional beams utilized to overcome the attenuation in these frequencies necessitate robust and efficient beamforming schemes. Nevertheless, antenna and beam management approaches still face challenges in highly mobile solutions, such as vehicular connectivity, with increasing number of bands. In this work, the concepts of spectrum mobility is studied along with antenna array management in multiple frequencies to improve beamforming under mobility. The spectrum mobility problem aims to select the optimal channel frequency and beam direction in each time slot to maximize data rate. This problem is formulated as a Partially Observable Markov Decision Process (POMDP) and Point-Based Value Iteration (PBVI) algorithm is used to find a policy with performance guarantees. Numerical examples confirm the efficacy of the resulting policy for multiple available frequency bands, even when the user mobility significantly deviates from models assumed during policy generation.