High-Resolution Channel Estimation for Intelligent Reflecting Surface-Assisted MmWave Communications

Abstract

In this paper, we study the high-resolution channel estimation problem for intelligent reflecting surface (IRS)assisted millimeter wave (mmWave) multiple-input-multipleoutput (MIMO) communications, which is a prerequisite to guarantee further high-rate data transmission. Considering the typical sparsity of mmWave channels, we formulate the cascaded channel estimation problem from a sparse signal recovery perspective, and then propose a novel two-step cascaded channel estimation protocol to estimate the cascaded user-IRS-base station channel with high-resolution for IRS-assisted mmWave MIMO communications. More specifically, the first step is to estimate the coarse angular domain information (ADI) and further establish the robust uplink by beam training. In the second step, by exploiting the coarse ADI, an adaptive grid matching pursuit (AGMP) algorithm is proposed to estimate the high-resolution cascaded channel state information (CSI) with low complexity. Simulation results verify that the proposed two-step channel estimation protocol significantly outperforms the state-of-the-art scheme, i.e., beam training based channel estimation, and meanwhile can reap near-optimal system performance achieved by perfect CSI.

A General Framework for RIS-Aided mmWave Communication Networks: Channel Estimation and Mobile User Tracking

“…3 , and Θ V is the last configured set of phases by the BS at the V'-th stage of beam searching process. By exploiting the angles obtained from (20) and by substituting them in (13), Ĝ can be estimated directly as…”

“…Again, using the same method, [19] tries to find a sparse representation of the cascaded BS-RIS-UE channel in mmWave downlink system with the help of transposed Khari-Rao product and Kronecker product. The most recent work for channel estimation in mmWave systems was in [20], where a two-stage cascaded channel estimation protocol is proposed by exploiting the sparsity of mmWave MIMO channel of single BS, RIS, and UE. In the first stage, the beam searching approach is introduced to have high angular domain information, then in a second stage, an adaptive grid matching pursuit algorithm is proposed to estimate the high-resolution cascaded channel.…”