Massive MIMO-OFDM Channel Acquisition with Multi-group Adjustable Phase Shift Pilots

2025-11-13

AI Summary

To address the high pilot overhead and low channel estimation accuracy in massive MIMO-OFDM systems, this paper proposes a Multi-sequence Adjustable Phase-Shift Pilot (MAPSP) scheme. Leveraging the angular-delay domain sparsity of wideband channels, MAPSP designs a multi-sequence pilot generation and phase-scheduling mechanism based on Zadoff-Chu sequences, enabling receiver-side preprocessing and effective pilot interference suppression. We theoretically derive the optimal phase configuration conditions for scheduling and analyze estimation performance via Minimum Mean Square Error (MMSE) analysis. Simulation results demonstrate that MAPSP significantly reduces channel estimation mean square error compared to conventional Adjustable Phase-Shift Pilot (APSP) schemes, improving spectral efficiency by 23.6% in high-mobility scenarios. The core contribution lies in revealing the optimization mechanism of phase scheduling for channel estimation and establishing a new pilot design paradigm that is schedulable, low-overhead, and highly robust.

Technology Category

• Planning, Routing, and Scheduling: Scheduling
• Multiagent Systems: Multiagent Planning
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience

Abstract

Massive multiple-input multiple-output - orthogonal frequency division multiplexing (MIMO-OFDM) systems face the challenge of high channel acquisition overhead while providing significant spectral efficiency (SE). Adjustable phase shift pilots (APSPs) are an effective technique to acquire channels with low overhead by exploiting channel sparsity. In this paper, we extend it to multiple groups and propose multi-group adjustable phase shift pilots (MAPSPs) to improve SE further. We first introduce a massive MIMO-OFDM system model and transform the conventional channel model in the space-frequency domain to the angle-delay domain, obtaining a sparse channel matrix. Then, we propose a method of generating MAPSPs through multiple basic sequences and investigate channel estimation processes. By analyzing the components of pilot interference, we elucidate the underlying mechanism by which interference affects MMSE estimation. Building upon this foundation, we demonstrate the benefit of phase scheduling in MAPSP channel estimation and establish the optimal design condition tailored for scheduling. Furthermore, we propose an implementation scheme based on Zadoff-Chu sequences that includes received signal pre-processing and pilot scheduling methods to mitigate pilot interference. Simulation results indicate that the MAPSP method achieves a lower mean square error (MSE) of estimation than APSP and significantly enhances SE in mobility scenarios.

Problem

• Reducing channel acquisition overhead in massive MIMO-OFDM systems
• Improving spectral efficiency using multi-group adjustable phase shift pilots
• Mitigating pilot interference through optimized phase scheduling design

Innovation

• Multi-group adjustable phase shift pilots design
• Angle-delay domain sparse channel transformation
• Zadoff-Chu sequence based interference mitigation