Round Trip Time Estimation Utilizing Cyclic Shift of Uplink Reference Signal

Fuente: arXiv
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Main Authors: Gangula, Rajeev, Melodia, Tommaso, Mundlamuri, Rakesh, Kaltenberger, Florian
Format: Preprint
Published: 2024
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author Gangula, Rajeev
Melodia, Tommaso
Mundlamuri, Rakesh
Kaltenberger, Florian
author_facet Gangula, Rajeev
Melodia, Tommaso
Mundlamuri, Rakesh
Kaltenberger, Florian
contents In the context of fifth-generation new radio (5G NR) technology, it is not possible to directly obtain an absolute uplink (UL) channel impulse response (CIR) at the base station (gNB) from a user equipment (UE). The UL CIR obtained through the sounding reference signal (SRS) is always time-shifted by the timing advance (TA) applied at the UE. The TA is crucial for maintaining UL synchronization, and transmitting SRS without applying the TA will result in interference. In this work, we propose a new method to obtain absolute UL CIR from a UE and then use it to estimate the round trip time (RTT) at the gNB. This method requires enhancing the current 5G protocol stack with a new Zadoff-Chu (ZC) based wideband uplink reference signal (URS). Capitalizing on the cyclic shift property of the URS sequence, we can obtain the RTT with a significant reduction in overhead and latency compared to existing schemes. The proposed method is experimentally validated using a real-world testbed based on OpenAirInterface (OAI).
format Preprint
id arxiv_https___arxiv_org_abs_2410_04528
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Round Trip Time Estimation Utilizing Cyclic Shift of Uplink Reference Signal
Gangula, Rajeev
Melodia, Tommaso
Mundlamuri, Rakesh
Kaltenberger, Florian
Information Theory
Signal Processing
In the context of fifth-generation new radio (5G NR) technology, it is not possible to directly obtain an absolute uplink (UL) channel impulse response (CIR) at the base station (gNB) from a user equipment (UE). The UL CIR obtained through the sounding reference signal (SRS) is always time-shifted by the timing advance (TA) applied at the UE. The TA is crucial for maintaining UL synchronization, and transmitting SRS without applying the TA will result in interference. In this work, we propose a new method to obtain absolute UL CIR from a UE and then use it to estimate the round trip time (RTT) at the gNB. This method requires enhancing the current 5G protocol stack with a new Zadoff-Chu (ZC) based wideband uplink reference signal (URS). Capitalizing on the cyclic shift property of the URS sequence, we can obtain the RTT with a significant reduction in overhead and latency compared to existing schemes. The proposed method is experimentally validated using a real-world testbed based on OpenAirInterface (OAI).
title Round Trip Time Estimation Utilizing Cyclic Shift of Uplink Reference Signal
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2410.04528