标题：WallSense: Device-Free Indoor Localization Using Wall-Mounted UHF RFID Tags
作者：Ma, Liang; Liu, Meng; Wang, Hongjun; Yang, Yang; Wang, Na; Zhang, Yajun
作者机构：[Ma, Liang; Liu, Meng; Wang, Hongjun; Yang, Yang; Wang, Na; Zhang, Yajun] Shandong Univ, Sch Informat Sci & Engn, Qingdao 266237, Peoples R China.
通讯作者：Wang, HJ;Yang, Y
通讯作者地址：[Wang, HJ; Yang, Y]Shandong Univ, Sch Informat Sci & Engn, Qingdao 266237, Peoples R China.
关键词：RFID; indoor localization; device-free; PSO; low cost
摘要：To achieve device-free indoor localization without the active participation of the users, this paper presents WallSense, a device-free indoor localization system based on off-the-shelf Radio RFID (Radio-Frequency Identification) equipment. The system deploys two orthogonal tag arrays in adjoining walls and uses the RSSI and phase information measured by RFID readers to localize the target. By differentiating the backscattered signal between adjacent tag pairs, WallSense is able to eliminate most undesirable factors and extract information directly related to the location of the target. By applying Particle Swarm Optimization (PSO) with a novel weighted fitness function and combining the localization result of two orthogonal tag arrays, the system is able to localize the target with high accuracy. Experiments show that the system is able to localize human target with 0.24 m median error. Also, WallSense has low deployment overhead and do not require the users to carry any devices.