Bluetooth Extended Advertising: Analysis and Optimization of Scanning Performance Degradation

This study conducts a comprehensive empirical analysis of the extended advertising feature of Bluetooth Low Energy introduced in the Bluetooth 5.0 Core Specification. We first deconstruct its architectural transformation compared to legacy advertising, focusing on the implementation principles and key parameters of extended advertising and extended scanning. Subsequently, through in-depth testing of the protocol stacks of four major chip suppliers (Nordic, Silicon Labs, Realtek, and Telink), we quantified the differences in key timing parameters, such as auxiliary offset and state switching time, and showed how these differences directly result in significant scanning performance gaps. These gaps are observed under scenarios including interference-free conditions, coexistence of advertising and scanning, interference from surrounding extended advertising, and Wi-Fi interference. Our analysis further highlights protocol-level challenges, such as an undefined frequency hopping method and reduced scanning capabilities under interference. Based on this analysis, we propose an engineering guideline for parameter optimization, anti-interference frequency-hopping mechanisms, and efficient Link Layer filtering strategies. This work provides engineers and researchers with insight to navigate the complexities of extended advertising and to develop reliable, high-performance connectionless applications.