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Main Authors: Li, Sijia, Sun, Rui, Xu, Bing, Liu, Yuanwei
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2508.02559
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author Li, Sijia
Sun, Rui
Xu, Bing
Liu, Yuanwei
author_facet Li, Sijia
Sun, Rui
Xu, Bing
Liu, Yuanwei
contents Although direct position estimation (DPE) has been demonstrated to offer enhanced robustness in GNSS receivers, its theoretical limits and performance in OFDM based positioning systems remain largely unexplored. In this paper, the Cramér-Rao bound (CRB) for DPE using OFDM based cellular signals is derived and benchmarked against the conventional two-step positioning method to assess their relative performance in non-line-of-sight (NLOS) dominated multipath environments. Numerical results reveal that 1) the DPE method consistently outperforms the two-step approach in OFDM systems under all evaluated conditions; 2) a large bandwidth is crucial in both methods, and increasing subcarrier spacing is more beneficial for a fixed bandwidth; 3) utilizing multiple OFDM symbols for positioning leads to substantial improvements in localization accuracy compared to relying on a single symbol. However, further increasing the number of symbols yields marginal improvements while significantly increasing computational complexity.
format Preprint
id arxiv_https___arxiv_org_abs_2508_02559
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cramér-Rao Bound for Direct Position Estimation in OFDM Based Cellular Systems
Li, Sijia
Sun, Rui
Xu, Bing
Liu, Yuanwei
Signal Processing
Although direct position estimation (DPE) has been demonstrated to offer enhanced robustness in GNSS receivers, its theoretical limits and performance in OFDM based positioning systems remain largely unexplored. In this paper, the Cramér-Rao bound (CRB) for DPE using OFDM based cellular signals is derived and benchmarked against the conventional two-step positioning method to assess their relative performance in non-line-of-sight (NLOS) dominated multipath environments. Numerical results reveal that 1) the DPE method consistently outperforms the two-step approach in OFDM systems under all evaluated conditions; 2) a large bandwidth is crucial in both methods, and increasing subcarrier spacing is more beneficial for a fixed bandwidth; 3) utilizing multiple OFDM symbols for positioning leads to substantial improvements in localization accuracy compared to relying on a single symbol. However, further increasing the number of symbols yields marginal improvements while significantly increasing computational complexity.
title Cramér-Rao Bound for Direct Position Estimation in OFDM Based Cellular Systems
topic Signal Processing
url https://arxiv.org/abs/2508.02559