
Erik Sandgren developed and stabilized advanced Bluetooth Channel Sounding features across the nrfconnect/sdk-nrf and renesas/zephyr repositories, focusing on measurement accuracy, reliability, and maintainability. He modernized memory management APIs, improved concurrency handling, and enhanced distance estimation pipelines using C and Zephyr RTOS. Erik implemented robust signal processing for missing channel data, introduced configurable measurement modes, and added detailed logging to streamline debugging. His work included hardware-level debugging support and unit testing, ensuring deterministic behavior and easier onboarding. Through careful documentation and code ownership management, Erik delivered well-architected firmware and embedded systems solutions that improved Bluetooth performance and developer productivity.
March 2026: Delivered and stabilized four key items in nrfconnect/sdk-nrf, reinforcing Bluetooth reliability and interoperability. Highlights include RTT-based distance estimation fix for RTT-only measurements, control of Remote PHY updates to improve Android interoperability, GPIO-based radio event debugging support for timing analysis on nRF54L, and BLE Long Range coded PHY routing with a DISABLED state to manage packet turnaround. Expanded test coverage and developer documentation accompany these changes, underscoring a focus on stability, interoperability, and developer productivity.
March 2026: Delivered and stabilized four key items in nrfconnect/sdk-nrf, reinforcing Bluetooth reliability and interoperability. Highlights include RTT-based distance estimation fix for RTT-only measurements, control of Remote PHY updates to improve Android interoperability, GPIO-based radio event debugging support for timing analysis on nRF54L, and BLE Long Range coded PHY routing with a DISABLED state to manage packet turnaround. Expanded test coverage and developer documentation accompany these changes, underscoring a focus on stability, interoperability, and developer productivity.
February 2026 (nrfconnect/sdk-nrf): Implemented Bluetooth RAS enhancements to improve configurability, distance estimation accuracy, and reliability. Key accomplishments include: configurable CS step modes with enhanced distance logging in ras_initiator; RTT-only measurement support with minimum APs and quality reporting in cs_de_calc; separate distance estimate buffers per antenna path to improve per-path tracking and reliability; and a fix to the argument order in ras initiator to resolve warnings and restore proper functionality.
February 2026 (nrfconnect/sdk-nrf): Implemented Bluetooth RAS enhancements to improve configurability, distance estimation accuracy, and reliability. Key accomplishments include: configurable CS step modes with enhanced distance logging in ras_initiator; RTT-only measurement support with minimum APs and quality reporting in cs_de_calc; separate distance estimate buffers per antenna path to improve per-path tracking and reliability; and a fix to the argument order in ras initiator to resolve warnings and restore proper functionality.
January 2026 (nrfconnect/sdk-nrf): Delivered two high-impact enhancements focusing on measurement accuracy and maintainability in Channel Sounding. Emphasized business value through improved distance estimation and clearer sample organization, with clear traceability via commit history.
January 2026 (nrfconnect/sdk-nrf): Delivered two high-impact enhancements focusing on measurement accuracy and maintainability in Channel Sounding. Emphasized business value through improved distance estimation and clearer sample organization, with clear traceability via commit history.
Month: 2025-11 — Focused on delivering Channel Sounding capabilities, improving CS_DE accuracy, and strengthening testing and governance around the CS_DE module in the nRF Connect SDK. Key outcomes include experimental Channel Sounding support for nRF54H20, updates to BLE CS maturity modeling, accuracy fixes in distance estimation (negative ToF handling and IFFT offset), internal CS_DE improvements with FFT size configuration, added unit tests for cs_de_calc, and updated code ownership. These deliverables enhance measurement reliability, calibration accuracy, maintainability, and accelerate business value for CS-enabled devices.
Month: 2025-11 — Focused on delivering Channel Sounding capabilities, improving CS_DE accuracy, and strengthening testing and governance around the CS_DE module in the nRF Connect SDK. Key outcomes include experimental Channel Sounding support for nRF54H20, updates to BLE CS maturity modeling, accuracy fixes in distance estimation (negative ToF handling and IFFT offset), internal CS_DE improvements with FFT size configuration, added unit tests for cs_de_calc, and updated code ownership. These deliverables enhance measurement reliability, calibration accuracy, maintainability, and accelerate business value for CS-enabled devices.
September 2025 monthly summary: Across renesas/zephyr and nrfconnect/sdk-nrf, delivered and stabilized Bluetooth Channel Sounding (CS) capabilities with improvements in reliability, accuracy, and observability. Implemented deterministic CS sampling and user-facing feedback, enhanced distance estimation pipeline to handle missing/unusable channels with robust IFFT-based processing, and accelerated update cadence to provide more timely ranging data. Fixed core data integrity in CS de-embedding by correcting antenna-path pcts mapping, and added comprehensive CS configuration logging to simplify debugging and analysis. The work spans cross-repo feature improvements, targeted bug fixes, and observability enhancements, delivering clear business value through more reliable CS-based distance estimates, faster feedback loops, and improved debugging visibility.
September 2025 monthly summary: Across renesas/zephyr and nrfconnect/sdk-nrf, delivered and stabilized Bluetooth Channel Sounding (CS) capabilities with improvements in reliability, accuracy, and observability. Implemented deterministic CS sampling and user-facing feedback, enhanced distance estimation pipeline to handle missing/unusable channels with robust IFFT-based processing, and accelerated update cadence to provide more timely ranging data. Fixed core data integrity in CS de-embedding by correcting antenna-path pcts mapping, and added comprehensive CS configuration logging to simplify debugging and analysis. The work spans cross-repo feature improvements, targeted bug fixes, and observability enhancements, delivering clear business value through more reliable CS-based distance estimates, faster feedback loops, and improved debugging visibility.
Month: 2025-01. Delivered architectural cleanup and stability improvements across Bluetooth controller and SoftDevice stack in two repositories (sdk-nrf and sdk-nrfxlib). Focused on modernizing memory management, improving reliability, and documenting changes to enable smoother integration with nrfxlib and future configurations. Key outcomes include modernization of the Bluetooth controller memory management API, addressing stability and concurrency issues in the SoftDevice Controller, and reliability improvements in MPSL with targeted cleanups and errata application. These changes reduce field risk, improve deterministic behavior under load, and pave the way for easier maintenance and future enhancements.
Month: 2025-01. Delivered architectural cleanup and stability improvements across Bluetooth controller and SoftDevice stack in two repositories (sdk-nrf and sdk-nrfxlib). Focused on modernizing memory management, improving reliability, and documenting changes to enable smoother integration with nrfxlib and future configurations. Key outcomes include modernization of the Bluetooth controller memory management API, addressing stability and concurrency issues in the SoftDevice Controller, and reliability improvements in MPSL with targeted cleanups and errata application. These changes reduce field risk, improve deterministic behavior under load, and pave the way for easier maintenance and future enhancements.

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