Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so t...Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.展开更多
The misreading problem of a passive ultra-high-frequency(UHF)radio frequency identification(RFID)tag is a frequent problem arising in the field of librarianship.Unfortunately,existing solutions are something inefficie...The misreading problem of a passive ultra-high-frequency(UHF)radio frequency identification(RFID)tag is a frequent problem arising in the field of librarianship.Unfortunately,existing solutions are something inefficient,e.g.,extra resource requirement,inaccuracy,and empiricism.To this end,under comprehensive analysis on the passive UHF RFID application in the librarianship scenario,a novel and judicious approach based on RFID localization is proposed to address such a misreading problem.Extensive simulation results show that the proposed approach can outperform the existing ones and can be an attractive candidate in practice.展开更多
Internet of Things (IoT) has attracted extensive interest from both academia and industries, and is recognized as an ultimate infrastructure to connect everything at anytime and anywhere. The implementation of IoT gen...Internet of Things (IoT) has attracted extensive interest from both academia and industries, and is recognized as an ultimate infrastructure to connect everything at anytime and anywhere. The implementation of IoT generally faces the challenges from energy constraint and implementation cost. In this paper, we will introduce a new green communication paradigm, the ambient backscatter (AmBC), that could utilize the environmental wireless signals for both powering a tiny-cost device and backscattering the information symbols. Specifically, we will present the basic principles of AmBC, analyze its features and advantages, suggest its open problems, and predict its potential applications for our future IoT.展开更多
Automated attendance management system will reduce complexity by eliminating plenty of manual processes involved in attendance system and calculating hours attended. This paper presents a simple technique of taking st...Automated attendance management system will reduce complexity by eliminating plenty of manual processes involved in attendance system and calculating hours attended. This paper presents a simple technique of taking student attendance in the form of an Internet of Things (IoT) based system that records the attendance using fingerprint-based system and stores them securely in a database. We use NodeMCUV3, RFID Module and Fingerprint sensor module in our system. The fingerprint module is responsible for authentication of the students. RFID Module is used to scan the RFID tag and sends data to the central server. By using this information, the system will generate an attendance report which can be accessed for further use.展开更多
基金supported in part by National Natural Science Foundation of China under Grant Nos.61971029 and U22B2004in part by Beijing Municipal Natural Science Foundation under Grant No.L222002.
文摘Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.
文摘The misreading problem of a passive ultra-high-frequency(UHF)radio frequency identification(RFID)tag is a frequent problem arising in the field of librarianship.Unfortunately,existing solutions are something inefficient,e.g.,extra resource requirement,inaccuracy,and empiricism.To this end,under comprehensive analysis on the passive UHF RFID application in the librarianship scenario,a novel and judicious approach based on RFID localization is proposed to address such a misreading problem.Extensive simulation results show that the proposed approach can outperform the existing ones and can be an attractive candidate in practice.
基金supported in part by National Key R&D Program of China under Grant 2016YFE0200900part by Scientific Research Program of Beijing Municipal Commission of Education under Grant KM201910853003part by Major projects of Beijing Municipal Science and Technology Commission under Grant Z181100003218010
文摘Internet of Things (IoT) has attracted extensive interest from both academia and industries, and is recognized as an ultimate infrastructure to connect everything at anytime and anywhere. The implementation of IoT generally faces the challenges from energy constraint and implementation cost. In this paper, we will introduce a new green communication paradigm, the ambient backscatter (AmBC), that could utilize the environmental wireless signals for both powering a tiny-cost device and backscattering the information symbols. Specifically, we will present the basic principles of AmBC, analyze its features and advantages, suggest its open problems, and predict its potential applications for our future IoT.
文摘Automated attendance management system will reduce complexity by eliminating plenty of manual processes involved in attendance system and calculating hours attended. This paper presents a simple technique of taking student attendance in the form of an Internet of Things (IoT) based system that records the attendance using fingerprint-based system and stores them securely in a database. We use NodeMCUV3, RFID Module and Fingerprint sensor module in our system. The fingerprint module is responsible for authentication of the students. RFID Module is used to scan the RFID tag and sends data to the central server. By using this information, the system will generate an attendance report which can be accessed for further use.
