RFID or Radio Frequency Identification has been touted as the “Internet of Things.” An RFID system enables automated tracking for objects even when they are not in range of sight. RFID systems have been widely deployed in supply chain management and have found several applications in medical pedigree, sensor networks and animal tracking.
An RFID system conforming to the Generation 2 Electronic Product Code (EPC) protocol typically has three layers as shown in the following diagram from the EPCglobal website.
When a tag is read by a reader, the Application Level Events (ALE) layer exposes various events such as Tag arrival, Tag depart or Tag read. For a large organization, the higher layers in the architecture can subscribe to possibly millions of such events. For the tracking to be meaningful, making sense of these events is important.
The ALE layer filters the events and exposes the upper layers to meaningful data. The phenomenon known as jitter may be still occur in the upper layers so it is best to design an RFID application that includes some sort of filtering in these layers as well.
Event processing architecture forms the core of any RFID tracking system. Processing multiple streams of simple events with the goal of identifying meaningful event data is important. Multiple events can also be combined to form a more complex event that can be directly modeled by the business logic.
RFID based technologies provide the most effective way of tracking objects among current technologies. However, it would be wrong to assume that this technology is all about tags and readers. RFID tracking is a whole system where all its layers play an important part. Any RFID system should be developed keeping this framework in mind.