Data Storage in RFID Systems

Abstract

One of the advantages of the RFID technology over the still more widespread optical barcodes is the comparatively large data storage capacity. Conventional 1-dimensional barcodes can store just few bytes of data. For instance, the EAN13-code used at the point of sale in Europe stores 13 numerical digits identifying country, product manufacturer, and product type. There is no means for identifying each item uniquely. More complex 2dimensional barcodes or larger 1-dimensional barcodes extend the amount of data that can be stored. This comes at the cost of a larger printing area as long as the readability shall not decrease. While the amount of data that can be stored using optical barcodes is therewith limited by the available area, RFID transponders offer a more comprehensive data storage capacity. Already comparatively simple tags can store a serial number capable of identifying objects globally uniquely. RFID transponders can thus serve as a means of unique identification for different kinds of objects like clothes, foods, or documents. Transponders that are more expensive can store an even larger amount of data. For instance, additional data describing the tagged objects, a documentation of the objects’ history, or even data putting the object in the context of other objects can be stored. The question arises how to make use of the additional capabilities. What data should be stored directly on the RFID transponders and what data should be stored in databases in the backend of a system? The design decision influences many characteristics of the overall RFID system. Thus, data storage considerations are an important part in planning the architecture of such a system. This book chapter discusses different design possibilities for data storage in RFID systems and their impact on the quality factors of the resulting system. As will be shown, many characteristics of the systems are influenced. The design decision on the data storage in an RFID system is therewith of great importance. The decision should thus be taken with care considering all relevant aspects. Note that this book chapter relates only to RFID transponders used exclusively as data storage units. Transponders with processors, cryptographic hardware, or sensors require partially separate inspection and are out of scope.