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Multi-User Channel Estimation in OFDMA Uplink Systems Based on Irregular Sampling and Reduced Pilot Overhead

This paper considers multiuser OFDMA uplink transmissions over doubly selective channels. We propose a pilot-aided channel estimator based on irregular sampling techniques. Our novel estimator features several benefits: it has low complexity, excellent performance, and enables highly flexible subcarrier allocation. Simulation results show that our scheme significantly outperforms conventional least-squares channel estimation and allows to support high-rate users with reduced pilot overhead.