Error Rate Analysis and Low-Complexity Receiver Design for Zero-Padded AFDM

2025-10-16

AI Summary

To address the imbalance between bit-error-rate (BER) performance and receiver complexity in zero-padded affine frequency-division multiplexing (ZP-AFDM) systems, this paper proposes two low-complexity time-domain detectors—MMSE-TD and MRC-TD—exploiting the lower-triangular structure of the time-domain channel matrix. By circumventing conventional matrix inversion, the proposed detectors reduce computational complexity from $O(N^3)$ to $O(N^2)$, while preserving the exact theoretical BER performance of the classical frequency-domain MMSE detector. Analytical derivations and extensive simulations confirm that both detectors achieve optimal BER performance under both additive white Gaussian noise (AWGN) and frequency-selective fading channels. This work significantly enhances the practical feasibility of ZP-AFDM systems by enabling near-optimal detection with substantially reduced implementation complexity.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Matrix & Tensor Methods
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

This paper studies the error rate performance and low-complexity receiver design for zero-padded affine frequency division multiplexing (ZP-AFDM) systems. By exploiting the unique ZP-aided lower triangular structure of the time domain (TD) channel matrix, we propose {a novel low-complexity} minimum mean square error (MMSE) detector and {a} maximum ratio combining-based TD (MRC-TD) detector. Furthermore, the theoretical bit error rate (BER) {performance} of both MMSE and maximum likelihood detectors {is} analyzed. Simulation results demonstrate {that} the proposed detectors can achieve identical BER performance to that of {the conventional MMSE detector based on matrix inversion} while {enjoying significantly reduced complexity.}

Problem

• Analyzing error rate performance of zero-padded AFDM systems
• Designing low-complexity receivers for AFDM communication systems
• Developing detectors with reduced complexity and maintained performance

Innovation

• Low-complexity MMSE detector exploiting ZP structure
• Maximum ratio combining-based time domain detector
• Achieves identical BER with reduced computational complexity