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Filter Design of Wireless Base Station Power Supply

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zte Communications 2024年

作者： LI Wei GUO Wei WANG Zhida zte corporation

The design of electromagnetic interference (EMI) filters needs to fulfill the EMI standards. Designing a filter is a time-consuming process for new engineers as well as for those experienced engineers. This paper measured and compared the noise spectrum of the wireless base station power prototype with and without the original filter. The ideal insertion loss (IL) of the original filter is obtained by combining calculation and simulation. It is pointed out that the effect of the original filter is not good. Based on the improved insertion-loss method， the source impedance model of the prototype is established by combining measurement and theory. A procedure for designing EMI filters for switch power supply will be presented. The filter design procedure makes it possible to design filters quickly and easily. Finally， the proposed filter design method is proved to be effective by the EMI measurement of the wireless base station power supply prototype.

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Filter Design of Wireless Base Station Power Supply

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zte Communications 2024年第1期22卷 95-105页

作者： LI Wei GUO Wei WANG Zhida zte corporation Shenzhen 518057China

The design of electromagnetic interference(EMI)filters needs to fulfill the EMI standards.Designing a filter is a time-consuming process for new engineers as well as for those experienced engineers.This paper measures and compares the noise spectrum of the wireless base station power prototype with and without the original filter.The ideal insertion loss(IL)of the original filter is obtained by combining calculation and simulation.It is pointed out that the effect of the original filter is not good.Based on the improved insertion-loss method,the source impedance model of the prototype is established by combining measurement and theory.A procedure for designing EMI filters for switch power supply will be presented.The filter design procedure makes it possible to design filters quickly and easily.Finally,the proposed filter design method is proved to be effective by the EMI measurement of the wireless base station power supply prototype.

关键词： electromagnetic compatibility common mode noise EMI filter

Real-Time 4-Mode MDM Transmission Using Commercial 400G OTN Transceivers and All-Fiber Mode Multiplexers

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zte Communications 2024年

作者： REN Fang LI Yidan YE Bing LIU Jianguo CHEN Weizhang Department of WDM System Design zte corporation University of Science and Technology Beijing

Weakly-coupled mode division multiplexing (MDM) technique is considered a promising candidate to enhance the capacity of an optical transmission system， in which mode multiplexers/demultiplexers (MMUX/MDEMUX) with low insertion loss and modal crosstalk are the key components. In this paper， a low-modal-crosstalk 4-mode MMUX/MDEMUX for the weakly-coupled triple-ring-core few-mode fiber (TRC-FMF) is designed and fabricated with side-polishing processing. The measurement results show that a pair of MMUX/MDEMUX and 25 km weakly-coupled TRC-FMF MDM link achieve low modal crosstalk of lower than -17.5 dB and insertion loss of lower than 11.56 dB for all the four modes. Based on the TRC-FMF and all-fiber MMUX/MDEMUX， an experiment for 25 km real-time 4-mode 3-λwavelength division multiplexing (WDM)-MDM transmission is conducted using commercial 400G optical transport network (OTN) transceivers. The experimental results prove weakly-coupled MDM techniques facilitate a smooth upgrade of the optical transmission system.

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Deadlock Detection:Background,Techniques,and Future Improvements

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zte Communications 2024年第2期22卷 71-79页

作者： LU Jiachen NIU Zhi CHEN Li DONG Luming SHEN Taoli Zhejiang University Hangzhou 310058China zte corporation Xi’an 710114China

Deadlock detection is an essential aspect of concurrency control in parallel and distributed systems,as it ensures the efficient utilization of resources and prevents indefinite delays.This paper presents a comprehensive analysis of the various deadlock detection techniques,including static and dynamic approaches.We discuss the future improvements associated with deadlock detection and provide a comparative evaluation of these techniques in terms of their accuracy,complexity,and scalability.Furthermore,we outline potential future research directions to improve deadlock detection mechanisms and enhance system performance.

关键词： deadlock detection static analysis dynamic analysis

Enhancing Code Quality with LLM in Software Static Analysis

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zte Communications 2024年

作者： NIU Zhi DONG Luming State Key Laboratory of Mobile Network and Mobile Multimedia Technology zte corporation

In our modern age of omnipresent and highly interconnected information technology， cybersecurity caused by software code vulnerabilities becomes ever more challenged， threatening the confidentiality， integrity， and availability of information systems during operation. To enhance software code quality， enterprises often incorporate static code analysis tools in Continuous Integration (CI) pipelines. but the side effects of high false positives and false negatives remain a challenge. The advent of LLM like ChatGPT AI model presents an opportunity to address this challenge. In this paper， we propose a method utilizing the custom-built Nebula-coder AI model for detecting and fixing code security issues in real-time during the developer’s personal build process. We construct a static code checking rule knowledge base through summarizing and classifying CWE code security problems identified by security teams and quality assurance teams. The rule knowledge base is combined with CodeFuse-processed code contexts to serve as inputs for an AI code security detection microservice， which assists in identifying code quality and security issues. If any abnormalities are detected， they are addressed by an AI code security patching microservice， which alerts the developer and requests confirmation before committing the code into the repository. Experimental results show that our approach effectively improves code quality. We developed a VSCode plugin for code alert detection and repair based on LLMs， which facilitates test shift-left and lowers the risk of software development.

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Degree of Freedom Analysis for Holographic MIMO Based on a Mutual-Coupling-Compliant Channel Model

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zte Communications 2024年

作者： SUN Yunqi JIAN Mengnan YANG Jun ZHAO Yajun CHEN Yijian State Key Laboratory of Mobile Network and Mobile Multimedia Technology zte corporation

Degree of freedom (DOF) is a key indicator for spatial multiplexing layers of a wireless channel. Traditionally， the channel of a multiple-input multiple-output (MIMO) half-wavelength dipole array has a DOF that equals the antenna number. However， recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered. We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO (HMIMO) channel and give a upper bound of the DOF with strong mutual coupling. Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared to a half-wavelength MIMO system.

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Optimization of High-Concurrency Conflict Issues in Execute-Order-Validate Blockchain

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zte Communications 2024年第2期22卷 19-29页

作者： MA Qianli ZHANG Shengli WANG Taotao YANG Qing WANG Jigang Shenzhen University Shenzhen 518000China zte corporation Shenzhen 518057China

With the maturation and advancement of blockchain technology,a novel execute-order-validate(EOV)architecture has been proposed,allowing transactions to be executed in parallel during the execution phase.However,parallel execution may lead to multi-version concurrency control(MVCC)conflicts during the validation phase,resulting in transaction invalidation.Based on different causes,we categorize conflicts in the EOV blockchain into two types:within-block conflicts and cross-block conflicts,and propose an optimization solution called FabricMan based on Fabric v2.4.For within-block conflicts,a reordering algorithm is designed to improve the transaction success rate and parallel validation is implemented based on the transaction conflict graph.We also merge transfer transactions to prevent triggering multiple version checks.For cross-block conflicts,a cache-based version validation mechanism is implemented to detect and terminate invalid transactions in advance.Experimental comparisons are conducted between FabricMan and two other systems,Fabric and Fabric++.The results show that FabricMan outperforms the other two systems in terms of throughput,transaction abort rate,algorithm execution time,and other experimental metrics.

关键词： blockchain MVCC conflict reordering parallel validation transaction merging

Learned Distributed Query Optimizer:Architecture and Challenges

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zte Communications 2024年第2期22卷 49-54页

作者： GAO Jun HAN Yinjun LIN Yang MIAO Hao XU Mo Peking University Beijing 100871China zte corporation Shenzhen 518057China

The query processing in distributed database management systems(DBMS)faces more challenges,such as more operators,and more factors in cost models and meta-data,than that in a single-node DMBS,in which query optimization is already an NP-hard problem.Learned query optimizers(mainly in the single-node DBMS)receive attention due to its capability to capture data distributions and flexible ways to avoid hard-craft rules in refinement and adaptation to new hardware.In this paper,we focus on extensions of learned query optimizers to distributed DBMSs.Specifically,we propose one possible but general architecture of the learned query optimizer in the distributed context and highlight differences from the learned optimizer in the single-node ones.In addition,we discuss the challenges and possible solutions.

关键词： distributed query processing query optimization learned query optimizer

Adaptive Hybrid Forward Error Correction Coding Scheme for Video Transmission

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zte Communications 2024年第2期22卷 85-93页

作者： XIONG Yuhui LIU Zhilong XU Lingmin HUA Xinhai WANG Zhaoyang BI Ting JIANG Tao Huazhong University of Science and Technology Wuhan 430074China zte corporation Shenzhen 518057China

This paper proposes an adaptive hybrid forward error correction(AH-FEC)coding scheme for coping with dynamic packet loss events in video and audio transmission.Specifically,the proposed scheme consists of a hybrid Reed-Solomon and low-density parity-check(RS-LDPC)coding system,combined with a Kalman filter-based adaptive algorithm.The hybrid RS-LDPC coding accommodates a wide range of code length requirements,employing RS coding for short codes and LDPC coding for medium-long codes.We delimit the short and medium-length codes by coding performance so that both codes remain in the optimal region.Additionally,a Kalman filter-based adaptive algorithm has been developed to handle dynamic alterations in a packet loss rate.The Kalman filter estimates packet loss rate utilizing observation data and system models,and then we establish the redundancy decision module through receiver feedback.As a result,the lost packets can be perfectly recovered by the receiver based on the redundant packets.Experimental results show that the proposed method enhances the decoding performance significantly under the same redundancy and channel packet loss.

关键词： video transmission packet loss Reed-Solomon code Kalman filter