Wi-Fi-based indoor localization has been extensively studied for context-aware services. As a result, the accurate Wi-Fi-based indoor localization introduces a great location privacy threat. However, the existing solutions for location privacy protection are hard to implement on current devices. They require extra hardware deployment in the environment or hardware modifications at the transmitter or receiver side. To this end, we propose DOLOS, a system that can protect the location privacy of the Wi-Fi user with a novel signal obfuscation approach. DOLOSis a software-only solution that can be deployed on existing protocol-compliant Wi-Fi user devices. We provide this obfuscation by invalidating a simple assumption made by most localization systems -- "direct path signal arrives earlier than all the reflections to distinguish this direct path prior to estimating the location". However, DOLOS creates a novel software fix that allows the user to transmit the signal wherein this direct path arrives later, creating ambiguity in the location estimates. Our experimental results demonstrate DOLOS can degrade the localization accuracy of state-of-art systems by 6x for a single AP and 2.5x for multiple AP scenarios, thereby protecting the Wi-Fi user's location privacy without compromising the Wi-Fi communication performance.

翻译：基于Wi-Fi的室内定位技术已为情境感知服务得到广泛研究。因此，精确的Wi-Fi室内定位也带来了严重的定位隐私威胁。然而，现有的定位隐私保护方案难以在当前设备上实现，需要在环境中部署额外硬件或对收发端硬件进行改造。为此，我们提出DOLOS系统，该系统通过创新的信号混淆方法保护Wi-Fi用户的定位隐私。DOLOS是纯软件解决方案，可部署在现有符合协议标准的Wi-Fi用户设备上。我们通过颠覆大多数定位系统所做的简单假设来实现混淆——即“直达路径信号比所有反射信号更早到达，从而在估计位置前区分该直达路径”。而DOLOS创建了一种创新的软件修复方案，使用户能够发送直达路径延迟到达的信号，从而在位置估计中制造歧义。实验结果表明，DOLOS可将最先进系统的定位精度降低至单接入点场景的1/6和多接入点场景的2/5，从而在不影响Wi-Fi通信性能的前提下保护用户定位隐私。