分析log，解IQ数据，发现影响性能算法问题，提供解决方案

Project： 5G small cellDuty: Responsible for physical layer baseband algorithm design, software development.Achievement:1. Design DU-RU interface and synchronization mechanism. Design L1 Low timing and task distribution. Design L1 Low test mode, test method, and generate test vector with MATLAB 5G Toolbox. Collect statistics about CPU bbuPool load. Write the high level design document(Tier0). Completed L1 LOW algorithm design, software development and debugging. Do cycles optimization as well.2. Using 5G Toolbox to write MATLAB tools for decoding UL & DL IQ data. Use this tool to decode SSB，SIB1，msg2，msg4，PRACH，msg3，msg4 ACK from baseband IQ data，Fix bugs in toolbox. Use this tool to find bug and issue in our product. 3. Build 5G MATLAB link level simulation chain. To improve the shortcomings of the original Intel algorithm. Such as PRACH noise estimation and detection improvement, PRACH frequency offset estimation and pseudo peak cancellation, PRACH SNR，PUSCH PUCCH SNR estimation optimization. PRACH, PUSCH & PUCCH time offset estimation optimization, CP protection, PUCCH F0 detection optimization etc, PUSCH doppler optimization. Improve wireless performance in order to pass customer field test.4. I prepared more than 1,000 pages of training PPT for 5G 3GPP standard. Some of them are published in Wechat public account "Digital Signal Processing and AI". 5. Choose the suitable RRC parameter configuration for our product from the complex 5G RRC parameters database.

Project： LTE air interface sniffer equipment based on NXP4860, receive the air interface signals from both base stations and UE, decoding both DL and UL IQ, and then locate the target mobile phones Achievement：1. Use LS+2D-MMSE to design 2D-MMSE channel estimation algorithm to adapt to different channels, different speeds and different SNR. Compared with the original interpolation algorithm, I add an extra filter iin frequency-domain that improves performance by 3dB. A noise estimation algorithm based BOUMARD method is used for MMSE input. 2. Designed LTE downlink time-frequency synchronization algorithm, including coarse synchronization algorithm based on PSS and fine synchronization method based on CRS. An innovative frequency offset estimation algorithm is designed to estimate the frequency offset of PSS. Design a high-performance PSS , SSS detection algorithm under frequency offset situation, Design a neighbor cell interference cancellation algorithm, design a signal statistics combined methods under low SNR, all of these solution can anti-frequency offset, and anti-interference, and improve low SNR performance, thus can reduce both PFA and PMD in low SNR, and the algorithm has better cell search performance than other commercial UE with 6dB gain, The key technology can greatly improve the performance of multi-cell search under the frequency offset case. 3. Designed equalization reception algorithms for LTE transmission mode 1(SISO) /2 (SFBC)/ 3 (OL SM)/ 4 (CL SM)/ 7 (BF)/8 (BF) including a sequence of quantization, normalization, demodulation and quantization. Design IRC algorithm and its corresponding dynamic IRC/MRC switching algorithm significantly improve the anti-interference performance in non MIMO case. 4. Design a blind estimation algorithm of downlink power bias Pa and Pb under unknown RRC parameters, which solves the problem of constellation distortion caused by unknown RRC parameters in sniffer.

5. Design the industry leading PDCCH fully blind decoding algorithm under unknown RNTI condition in RRC connect case, use Bayesian classifier to determine the existence of frequency domain RE, use Viterbi decoding path metric, path differential metric, double decoding method to determine the most likely DCI type, AL type, judge if the RNTI and DCI content are correct. A DTX algorithm based on PDSCH constellation map was used to filter the false alarm PDSCH scheduling generated by the false alarm DCI, and totally reduce the false alarm probability. This set of key technologies makes it possible to analyze the air - interface signal in the RRC connected state. 6. An innovative uplink timing synchronization algorithm is designed. The initial synchronization is obtained by using the sliding correlation of the uplink DMRS sequence, and the fine synchronization is obtained by using the phase difference of the adjacent frequency domain RE of the DMRS, so that the uplink can obtain a good time-offset synchronization. 7. Since the DCI lengths of DCI2A and DCI2B are the same, the exact type of DCI cannot be determined during PDCCH processing. However, the PDSCH scheduled by DCI2A and DCI2B have different DMRS resource modes, so a decision algorithm based on DMRS location is designed to determine the type of DCI. 8. Design a high-performance downlink fine time-frequency synchronization algorithm, use long- term averaging to track them and compensate them, highly improve the system's reliability

Project： Nokia Femto PHY software based on TI DSP.Duty: CFAM author in charge of feature analysis, interface with algorithm team and co-design algorithm with them. Achievement:1. Submit a sPRACH physical layer standard FR to Multefire standards form.2. Design sPRACH receiving algorithm under B-IFDMA waveform, design a new interpolation based time-offset interpolation measurement, design a new frequency offset estimation based on OCC.3. Design PUCCH multi-user channel estimation algorithm, because frequency offset will bring interference between orthogonal codes (OCC), design anti-frequency offset multi-user reception algorithm. 4. Wrote CFAM (feature analysis) document for dev team. Applied for two algorithm patents

Project： ALU second gen SoC macro cell based on NXP 4860 chipDuty:I served as a member of the physical layer expert team and join the architecture design and algorithm design of LTE PHY software together with system engineers from Bell LABS in France and the United States. I am a team leader as well. I am PUSCH module owner, capacity feature owner.Achievement:1. Found a bug of POST IDFT SNR algorithm of NXP chip accelerator, deduced the correct formula of POST IDFT SNR, improved the demodulation performance under low SNR, found that PUSCH AN DTX performance problem under low SNR, and re-design the threshold simulation. And successfully solved the outfield performance problem of Verizon and ATT, and won the wireless president award of the company. 2. Optimized LLR quantization algorithm, optimized frequency offset compensation algorithm, optimized IRC/MAC switching threshold, solved some bugs of TA and HW delay, and provided strong support for solving outfield performance problems of products in operators. Derive and learn the baseband algorithm of ALU, wrote algorithm proof document including frequency offset estimation and compensation, time offset estimation and TA adjustment, UE velocity estimation, SNR estimation, time-frequency domain channel estimation, IRC and equalization, demodulation LLR quantization, PUSCH AN DTX detection, and inter-station interference elimination (NICE). PRACH front-end extraction filtering, PUCCH multi-user reception, BF DOA/EBB and so on. 3. Led the detailed design of software architecture for OLC, UL CoMP, IRC, CA, MU-MIMO, high-capacity base station and other features, and completed the detailed design documents of LLD and MAD software for these features. As the feature owner of Capacity, software optimization was carried out based on cache sharing and DSP instruction set, parallism and pipeline. The baseband capacity has been doubled.

Project: ALU first generation baseband softwareAchievement:1. Finish the FDD to TDD migration of LTE R8 version within 6 months.(Transplant between different DSPs)2. Developed physical layer MAC scheduling module, do implementation of 3GPP 36.213, and systematically learned LTE R8 physical layer protocol.3. 2-month business trip in Alcatel-Lucent, Germany. To learned DSP development method, and cooperated with German colleagues to complete the development of PUCCH receiving link and PUSCH UCI decoding code. 4. Develop DSP code of remote interference detection based on SRS.5. Development of 8 antenna feature of MAC scheduler

2008开始从事LTE宏基站物理层DSP软件研发，2013年开始从事物理层架构及算法工作，撰写架构设计文档，协议培训PPT，算法推导文档。解决多项性能问题，获得公司多项奖励。发表专利一篇

2008开始从事LTE宏基站物理层DSP软件研发，2013年开始从事物理层架构及算法工作，撰写架构设计文档，协议培训PPT，算法推导文档。解决多项性能问题，获得公司多项奖励。发表专利一篇