Radio-frequency identification (RFID) is a noncontact automatic identification technology that has been widely used in various modern industries. Due to the continuous improvement in sensing capabilities, energy autonomy, affordability, and usability, RFID is one of the key enabling technologies in realizing the Internet of Things (IoT). With their non-line-of-sight wireless transmission, wireless power, and sensing capability, lightweight RFID sensor tags can be connected to people or objects, which is crucial for future IoT applications such as healthcare, logistics, and manufacturing. The RFID approach with the simultaneous reading of multiple tag features can quickly identify connected "things" for further data communication and integration. Reducing the identification processing time for many tags located inside the interrogation range of the reader is essential. Therefore, an effective protocol must be developed to prevent collisions and reduce useless queries between the reader and tags to achieve rapid identification. Predetection tree-based algorithms, which are based on certain small predetection timeslots that tags can respond to, can eliminate unnecessary idle slots and prevent collision slots. In this paper, an efficient predetection-based anticollision algorithm has been proposed to achieve outstanding tag identification performance. The numbers of collision slots and idle slots are reduced by exploiting a novel predetection mechanism and slot size adjustment technique. Simulation results indicate that the proposed scheme reduces the tag identification time by approximately 30-60% compared with previously proposed predetection-based protocols. Moreover, the numbers of query cycles, collisions, and slots are smaller in the proposed scheme than in the previously proposed protocols.

Radio frequency identification (RFID) technology is one of the key enabling technologies to realize the IoT. With the capabilities of sensing, wireless communication, and wireless-powered, non-line-of-sight transmission, lightweight RFID sensor tags are a critical enabling technology for future IoT applications, such as logistics, manufacturing, and healthcare. In contrast to alternatives, such as barcodes and QR codes, the radio-frequency-powered identification approach featuring the simultaneous reading of multiple tags allows connected "things" to be identifiable for further data communication and integration. Therefore, an effective anticollision protocol should be developed between the reader and the tags to achieve rapid identification, especially in a system with a large number of RFID sensor tags. The dynamic slots collision tracking (DSCT) algorithm, which is based on a collision tracking technique, can reduce the prefix and the iteration overhead through a time-divided responding scheme. The DSCT protocol performs well when consecutive collisions occur. However, for nonconsecutive collisions, DSCT generates many idle time slots. Thus, the identification time cannot be reduced. In this paper, we present an enhanced DSCT (EDSCT) algorithm to reduce the identification time for nonconsecutive collisions. The simulation results reveal that the proposed algorithm can effectively reduce the identification delay and improve the slot efficiency.