Real-Time Firmware Development

Chowdam Ravi

Email: ***********.***@*****.***

Phone: +1-571-***-****

LinkedIn: (1) ravi chowdam LinkedIn

Career Objective:

Experienced Firmware Developer with over 18 years in wireless communication, specializing in 5G NR firmware development, NB-IoT/CAT-M, and Wi-Fi (WLAN) development (802.11 a/b/g/n/ac/ax). Proficient in downlink and uplink channel implementations (PDSCH, PBCH, PDCCH, PUSCH, PUCCH, PRACH) and NFAPI/FAPI layer development to enable seamless L1-to-higher-layer communication. Demonstrated expertise in protocol optimization, real-time troubleshooting, and supporting mission-critical systems. Seeking a challenging role to leverage my technical experience in cutting-edge wireless technology.

Core Skills:

Wireless Communication: 5G NR, LTE, NB-IoT, Carrier Aggregation, MU-MIMO, OFDM, OFDMA

Testing & Validation: Test case creation, execution, debugging, troubleshooting

Protocol Knowledge: L1 Layer, PHY Layer, MAC-PHY interface, Physical channels (PBCH, PDCCH, PDSCH, PUCCH, PUSCH, PRACH)

Software & Tools: MATLAB, C, Python, Verilog, Wireshark, Omni peek, Keysight, R&S Signal Generators/Analyzers, Anritsu

Operating Systems: Linux, Windows

Other Skills: Test automation, Agile methodologies, Configuration management, Regression testing

Education and Achievements

Master of Communication Systems Engineering

Anna University, Coimbatore, Tamil Nadu state, Graduated: 2007, CGPA: 8.55

Focus: Wireless Communications, Signal Processing, Digital Communication Systems

Bachelor of Electronics and Communication Engineering

Delhi University, Hyderabad, Telangana state, Graduated: 2003, Percentage: 66.67

Focus: Telecommunications, Digital Electronics

Awarded Best Employee twice at EdgeQ for outstanding contributions to firmware

development and successful project delivery, demonstrating commitment to quality

and efficiency.

National Conference Presentation Award: Presented a project on wireless

communication at a National Conference and won a prize for innovation and

technical excellence.

Professional Summary:

Developed Firmware for Downlink (DL) and Uplink (UL) Channels in 5G NR, ensuring robust communication and adherence to specifications.

Enhanced multi-carrier support up to 4 carriers and multi-bandwidth support for 5G NR to optimize network performance.

Written Code for Dynamic Memory Allocation in TXUs to enhance memory utilization effectively.

Designed and Coded NFAPI and FAPI to validate L2 to L1 layer integration and L1 functionality.

Written Code for SCTP and UCP socket programming for NFAPI DU and RU to ensure seamless transport of control messages.

Captured all channels on Wireshark and analyzed the results to ensure protocol compliance and performance optimization.

Tested and resolved real-time issues related to EVM and constellation points using VSG and VSA.

Performed low-level debugging by probing hardware signals with oscilloscopes and logic analyzers.

Implemented WLAN-802.11 Algorithms as Hardware Accelerators, including TXP, ED-AGC, Timers, Crypto, and TXC MIMO at the RTL level.

Developed WLAN-802.11 Algorithms as Firmware DSP.

Proficient in Fixed Point Coding using both Assembly and C languages.

Wrote C Code for Physical Layer (PHY) Functions and developed APIs for Medium Access Control (MAC).

Extensive experience with MAC protocols and packet analysis tools such as Wireshark and Omni Peek for WLAN.

Modified existing algorithms to comply with real-time specifications and ensure feasibility of implementations.

Developed driver code for HW modules in Assembly language.

Implemented SIFS optimization logic to achieve reduced turnaround times for SIFS.

Collaborated closely with the STQA team to address issues encountered during the certification process (Wi-Fi Alliance, Miracast, etc.).

Wrote C Code for controlling drivers and APIs for both PHY and MAC functionalities.

Conducted testing of the entire PHY and LMAC code on various platforms, including simulators, FPGAs, and emulators.

Ported firmware to actual silicon and successfully executed the bring-up process.

Resolved PHY and MAC interface level issues while establishing connections on Linux hosts, including throughput measurements (UDP, TCP, bidirectional, etc.) and multiple interfaces for peer-to-peer testing.

Addressed PHY and MAC interface level issues pertinent to Wi-Fi certifications, including bandwidth sharing, RTS-CTS, and SIFS.

Developed automation scripts in Python, Linux Bash, Windows DOS, and MATLAB.

Executed timing and memory optimizations, resolved deadlocks and runtime lockups, and addressed memory corruption issues.

Professional Experience

Sr. Staff Firmware Engineer

Edge Compute Wireless, June 2020 – Till Date

Location: Santa Clara, CA, USA

Customer Project: Dense Air and Radisys 5GNR and DU/RU

5G NR and Wi-Fi 6 (802.11ax) Firmware Development & Optimization

5G NR Downlink Channels: Developed and optimized firmware for key downlink channels (PDSCH, PBCH, PDCCH), ensuring data throughput and improved latency.

5G NR Uplink Channels: Implemented firmware for uplink channels (PUSCH, PUCCH, PRACH) with optimized control data transmission, contributing to robust connectivity and setup.

NFAPI/FAPI Layer Development: Designed and integrated NFAPI/FAPI layers for seamless communication between L1 and L2, supporting scalable and efficient base station deployments.

Testmac Development: Designed and implemented a custom testmac specifically tailored to validate the gNB functionalities within the Action Tech 5G solution. The testmac was built to simulate real-world conditions and test the gNB's performance across various scenarios.

Validation of Downlink and Uplink Channels: Developed the necessary test sequences to validate all UL/DL channels, including PDSCH, PUSCH, PDCCH, PRACH, and more, ensuring full compliance with 5G NR standards.

Wi-Fi 6 (802.11ax): Led development for 802.11ax features, including OFDMA, MU-MIMO, and beamforming, ensuring enhanced connectivity performance for high-density networks.

Senior Firmware Engineer

Mbit Wireless, November 2018 – June 2020

Customer Project: MB4200-B/CATM SoC Development

NB-IoT and CAT-M Firmware Development

Firmware Development for LTE L1 Physical Layer: Developed and optimized firmware for LTE L1 physical layer algorithms, focusing on key modules including DC, AGC, IFE, PSS, SSS, and RSRP.

Developed firmware for NB-IoT and CAT-M channels, focusing on low-power IoT communication, optimizing control channel efficiency and synchronization.

Collaborated closely with hardware and testing teams, validating uplink and downlink control channels and ensuring LTE-M compliance.

Lead Design Engineer

Imagination Technologies, September 2007 – November 2018

Customer Project: Wi-Fi Protocol Development (802.11 a/b/g/n/ac)

Control Firmware Development: Developed and optimized FSMs for TX and RX control for 802.11 standards, including 20/40/80MHz bandwidth, MIMO, beamforming, and other advanced features.

PHY/MAC Layer Integration: Worked extensively on PHY/MAC layer improvements, focusing on modulation, channel coding, and error control mechanisms.

Shannon (802.11n 1x1): An Imagination’s internal SOC, integrated the Shannon SOC chip into PURE radio (UK), Led firmware development for Wi-Fi protocols, implementing PHY and MAC layers for enhanced performance and reliability.

TZ5000 (802.11ac 2x2): A Toshiba’s SOC (http://toshiba.semicon-storage.com/eu/company/news/2015/04/assp-20150413-1.html).

Toshiba project: this SOC is planned for used in TV's. Key aspects in the project is handling the three DSP processors FSM's, DMA channels sharing for TX and RX path, implementing the beamforming feature.

DANUBE (802.11ac 2x2): An Imagination’s internal SOC with few hardware modifications from TZ5000. The same Hardware is productized in another format called CI40 (http://creatordev.io/ci40-iot-hub).

In addition Toshiba project: implemented the WIFI - Bluetooth coexistence protocol.

Fields of Interest:

Embedded systems, 5GNR, LTE, DSP, RTL, OFDM, OFDMA, MIMO, WLAN and Fixed-Point coding.

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