2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)最新文献

Challenges with linuxptp on Telco RAN deployments 在电信RAN部署中使用linuxptp的挑战

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615265

Maciej Machnikowski, R. Reddy, Zoltán Fodor

{"title":"Challenges with linuxptp on Telco RAN deployments","authors":"Maciej Machnikowski, R. Reddy, Zoltán Fodor","doi":"10.1109/ispcs49990.2021.9615265","DOIUrl":"https://doi.org/10.1109/ispcs49990.2021.9615265","url":null,"abstract":"Challenges with ptp4l on Telco RAN deployments.Linuxptp project is the most commonly adopted software implementation of the IEEE 1588 protocol on Linux-based systems.This paper identifies existing challenges and gaps in the current implementation of the linuxptp software stack. It is important to address these challenges to adapt to 4G/LTE and 5G/NR Telco RAN deployments. These findings result from the collaboration of Altiostar and Intel on IEEE 1588-based ptp4l implementations in O-RAN systems with a COTS NIC card.The most important challenges outlined in the paper include:•Lack of support for dynamic configuration in ptp4l•Lack of support for system-level management•Ptp4l sync state machine is not fully compliant to ITU-T G.8275.1/G.8275.2 standards•Link Aggregation(LAG)/Aggregation Ethernet(AE) Support•Non-compliance to ITU-T G.8265.1 standard•Required support for ITU-T G.8273.4(APTS/PTS) for resiliency or redundancy•Non-compliance to O-RAN.WG4.CONF.0.v2.00 O-RAN Fronthaul Working Group Conformance Test Specification•Missing SyncE and ESMC support•Missing support for multiple time domains•Multiple follower/slave portsThe paper shows how these challenges make industry applications much more complex, if not impossible. It may also lead to creation and implementation of non-standard solutions. Not addressing these gaps may lead to non-compliance with timing specs (ITUT/O-RAN), impacting the adoption rate of linuxptp in the RAN.","PeriodicalId":186103,"journal":{"name":"2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129346608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Portable, PTP-based Clock Synchronization Implementation for Microcontroller-based Systems and its Performance Evaluation 基于微控制器系统的便携式ptp时钟同步实现及其性能评估

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615250

András Wiesner, T. Kovácsházy

{"title":"Portable, PTP-based Clock Synchronization Implementation for Microcontroller-based Systems and its Performance Evaluation","authors":"András Wiesner, T. Kovácsházy","doi":"10.1109/ispcs49990.2021.9615250","DOIUrl":"https://doi.org/10.1109/ispcs49990.2021.9615250","url":null,"abstract":"Networked embedded systems are built from nodes utilizing Linux with its diverse network protocol stacks or on network-enabled Microcontrollers (MCU) with embedded operating systems like FreeRTOS with limited networking support. Clock synchronization in the form of IEEE 1588 (Precision Time Protocol, PTP) is also a common requirement in networked embedded systems today. Linux and other high-end embedded operating systems have kernel and application support for PTP, for example, Linux has the PTP Hardware Clock (PHC) kernel infrastructure and linuxptp user-space implementation for this. However, PTP support on embedded operating systems for MCUs is not common; and therefore, portable, good quality, open-source implementations are needed. This paper introduces our PTP based clock synchronization implementation and evaluates its baseline performance on the Texas Instruments TM4C1294 Tiva C network-enabled Cortex-M4F MCU using the Texas Instrument’s Connected LaunchPad development board as a hardware environment. Our implementation is built upon FreeRTOS embedded operating system and the LwIP embedded TCP/IP stack, two software components also widely applied by other network-enabled MCU manufacturers in their software packages (such as ST on the STM32F4/F7/H7 line). The implementation abstracts PTP packet timestamping, PPS signal generation, and external HW event timestamping, hopefully guaranteeing good portability. After presenting the software and hardware architecture of our system we also report our initial performance evaluation methodology and results.","PeriodicalId":186103,"journal":{"name":"2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132249110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Self-Learnning of the Dynamic, Non-linear Model of Frequency-Temperature Characteristic of Oscillators for Improved Clock Synchronization 改进时钟同步的振荡器频率-温度动态非线性模型的自学习

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615306

Viktor Vozár, T. Kovácsházy

{"title":"Self-Learnning of the Dynamic, Non-linear Model of Frequency-Temperature Characteristic of Oscillators for Improved Clock Synchronization","authors":"Viktor Vozár, T. Kovácsházy","doi":"10.1109/ispcs49990.2021.9615306","DOIUrl":"https://doi.org/10.1109/ispcs49990.2021.9615306","url":null,"abstract":"The frequency of oscillators depends on a lot of physical parameters; from which, the most influential one is the temperature of the resonator in most of the applications. For example, Temperature Compensated Crystal Oscillators (TCXO) and Owen-Controlled Crystal Oscillators (OCXO) are developed to reduce the frequency variation (drift) of the quartz oscillator due to temperature changes. On the other hand, precision frequency and/or clock synchronization solves the same problem by compensating such temperature-induced frequency variations in slave clocks by synchronizing them to a master clock. However, synchronization may fail, for example, due to communication problems, and the temperature-induced frequency drift becomes a problem again. In addition, steep temperature gradients may also cause problems in some applications as the servo in the synchronization implementation cannot keep the required performance in such situations. In the paper we introduce a solution, which measures the frequency-temperature characteristics of the oscillator during its synchronized state, builds a dynamic, non-linear model of it, and applies the specific model in any case when synchronization cannot be kept to compensate for temperature variations, in essence, we work toward a Software-Defined, Self-Learning TCXO (SD-TCXO). To facilitate this aim, first, we devised a measurement system to collect data about the frequencytemperature characteristics of oscillators, and then we selected, tuned, and validated a dynamic, non-linear system Hammerstein-Wiener model for the tested oscillator. Based on our results, the model improves the temperature variation of standard quartz oscillators by an order of magnitude, just by utilizing added temperatures sensor and some algorithms, easily providing TCXO level performance regarding temperature variations even in holdover situations or in case of steep temperature changes. (Abstract)","PeriodicalId":186103,"journal":{"name":"2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)","volume":"194 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134223882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Multi-Core Intra-Process Clock Synchronization 多核进程内时钟同步

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615343

James Coleman, Clark Newman, Yann-Hang Lee

引用次数: 0

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615307

引用次数: 0

ISPCS 2021 Table Of Contents ISPCS 2021目录

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615283

引用次数: 0

PTP Security Key Management Solutions PTP安全密钥管理解决方案

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615270

Martin Langer, S. Fries, Marius Rohde, Kai Heine, D. Sibold, R. Bermbach

引用次数: 2

[ISPCS 2021 Front cover] [ISPCS 2021封面]

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615255

引用次数: 0

Hyperbolic Positioning Accuracy Issues : Measurement Noise, Geometric Dilution of Position, and Synchronization Errors 双曲定位精度问题:测量噪声，几何位置稀释，和同步误差

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615272

M. Weiss, Charles Barry

引用次数: 0

[ISPCS 2021 Front matter] [ISPCS 2021前沿事项]

2021 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS) Pub Date : 2021-10-27 DOI: 10.1109/ispcs49990.2021.9615275

引用次数: 0