Development of an ultra-high radio-frequency identification system

Thesis (Ph.D. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2005.Ultra-high radio-frequency identification (UHF RFID) systems outperform all other RFID technologies in terms of throughput and reading range. UHF RFID tags and readers will be deployed on unprecedented scales during the next few years. This could result in problems of inter-operability and large-scale interference from readers. This thesis describes the systematic analysis of optimal requirements and the systematic derivation of a set of design objectives and guidelines for a UHF RFID system and air protocol that differs from other UHF RFID systems in use today. In brief, this is a system where the reader transmits little or no data to the tags and is therefore low noise and narrow band. This makes this system (and specifically the protocol) one that can support a higher density of readers, and thus leads to an improved system throughput and effectiveness. The principal challenge is to design and implement a tag protocol that addresses all of the requirements derived for the UHF RFID system. Thus, at the core of the system is the iP-X anti-collision protocol, a stochastic Aloha-like over-the-air communications protocol. The protocol is described and analysed in this work, both in terms of its throughput performance as an anti-collision protocol, and also in terms of its RF characteristics and benefits. The major result of this work is the successful implementation of a series of tag chips that have been designed to implement the protocol. Both readers and tags are currently in production and are being successfully marketed and sold worldwide.Doctora