RFID Challenges Barcoding

In the last few years, barcodes and magnetic stripes have greatly helped item management in the retail, health care and logistics sectors. A technology called RFID (Radio frequency identification) is touted to replace barcodes. RFID uses radio signals for automatic identification by transmitting data (tags) in a machine-readable form using radio frequency as the carrier medium.

The data in the tags corresponds to a particular application. For instance, it can transmit information about goods in a warehouse or courier packets in a logistics set-up. The advantage of RIFD is that it completely automates data recording, saving a lot of time.

RFID uses frequencies within the range of 50 KHz–2.5 GHz. An RFID system includes the following components: An RFID device (transponder or tag) that contains data about an item; an antenna used to transmit the RF signals between the reader and the RFID device and a RF transceiver that generates the RF signals; a reader that receives RF transmissions from an RFID device and passes the data to a host system for processing.

The frequency range to be used depends on the application of RIFD. For instance, RFID systems working on a low frequency range of 30 KHz to 500 KHz have a shorter reading range, lower reading speed and, therefore, costs less. It can be used for basic item identification. Consequently, high-frequency (850 MHz-950 MHz and 2.4 GHz-2.5 GHz) systems are more expensive and used for long distance applications, such as automatic toll collection. 

RFID tags can be active or passive. Active tags use external power sources whereas passive may not use one. The life of an active tag is limited by the life of the power source. Passive tags can be battery-powered or be a solid-state device. They work by reflecting the RF signal transmitted from the base transmitter and, in the process, add information by modulating the reflected signal. The size of the data that a tag can store depends on the vendor and the application. A typical tag carries no more than 2 KB of data, enough to store some basic information about the item it is on. However, the structure of the data is vendor dependent and proprietary. For list of vendors refer an

A big advantage with RFID is that it’s not dependent upon the line of sight, since it uses radio-frequency signals. Bar codes on the other hand are limited to line of sight because they use lasers. This advantage of RFID becomes more prominent in places where bar-code readers are difficult to use, for example, when the bar code is hidden due to messy packing, obstructions or environmental conditions. The other important advantage of RFID is the speed at which tags can be read. In most cases the response time is less than 100 milliseconds, while bar code systems take longer. 

Currently, RFID is not being used extensively due to lack of standardization. One vendor’s implementation could be totally different from anothers. Another issue is cost. A RFID reader costs around $1000, while a barcode system is relatively cheaper. So, although RFID is touted to replace barcodes, it won’t happen in the near future at least.

Ankit Khare