Pilot Beam Sequence Design for Channel Estimation in Millimeter-Wave MIMO Systems: A POMDP Framework

TL;DR

This paper introduces a POMDP-based adaptive pilot beam sequence design for channel estimation in large mmWave MIMO systems, leveraging channel sparsity and Markovian assumptions to optimize data transmission rates.

Contribution

It formulates the adaptive pilot design as a POMDP problem, providing an optimal method for channel estimation in large mmWave MIMO systems.

Findings

The proposed method improves channel estimation accuracy.

Numerical results validate the effectiveness of the POMDP-based design.

The approach maximizes data transmission rate over time.

Abstract

In this paper, adaptive pilot beam sequence design for channel estimation in large millimeter-wave (mmWave) MIMO systems is considered. By exploiting the sparsity of mmWave MIMO channels with the virtual channel representation and imposing a Markovian random walk assumption on the physical movement of the line-of-sight (LOS) and reflection clusters, it is shown that the sparse channel estimation problem in large mmWave MIMO systems reduces to a sequential detection problem that finds the locations and values of the non-zero-valued bins in a two-dimensional rectangular grid, and the optimal adaptive pilot design problem can be cast into the framework of a partially observable Markov decision process (POMDP). Under the POMDP framework, an optimal adaptive pilot beam sequence design method is obtained to maximize the accumulated transmission data rate for a given period of time. Numerical results are provided to validate our pilot signal design method and they show that the proposed method yields good performance.