Hybrid wireless localization with a new radio frequency beamforming scheme

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Many solutions have been developed in recent years to meet the increasing demand of short-range localization in the internet of things (IoT) era. Examples include systems based on wireless communication networks, sensor networks, radio-frequency identification (RFID), as well as frequency modulated continuous-wave (FMCW) and ultra-wideband (UWB) systems. Most of the solutions rely on established networks or interrogators, and the targets must carry devices such as cellular phones and RFID tags. FMCW/UWB systems can localize objects without requiring the targets to carry any device but need a large transmitted signal bandwidth to achieve desirable range resolution. This project will explore a radio frequency (RF) compressed sensing solution and a hybrid-mode localization mechanism for short-range wireless localization. The proposed solution will also be user-centered by efficiently sensing user activities and optimizing resource allocation. It will significantly reduce the hardware cost, power consumption, circuit complexity, spectrum usage, and signal processing load. The ultimate goal of this research is to achieve ubiquitous short-range wireless localization on low-cost mobile devices. It will influence many wireless systems and applications, and thus have broad impacts to our society.This project aims to develop the next generation wireless localization system. Different from conventional compressed sensing radar or localization systems that mostly perform data compression during or after demodulation, the proposed solution will efficiently compress data based on multi-beam radiation patterns produced by an advanced RF beamforming array. The array will probe the space with randomized radiation patterns instead of a single scanning beam, thus reducing the amount of spatial samples and the resources required to take the samples. Compared with conventional digital beamforming, the proposed solution is advantageous in lower hardware cost, less power consumption and lower circuit complexity. In addition, a hybrid-mode localization mechanism will be devised to fuse the advantages of Doppler/interferometry, frequency shift keying (FSK), and FMCW detection modes, so that the spectrum usage and signal processing load are kept to the minimum by switching the detection mode based on the status of the targets. The system will further reduce spectrum usage by user-centered operation, which efficiently senses and tracks human subjects based on human motion characteristics. Special localization algorithms will be derived to identify the unique human behavior that is distinct from other objects. The project will actively involve K-12 and undergraduate students in research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.