You would think that with the cost of RFID tags getting down to a reasonable level that bar codes would now become obsolete. The ongoing problem with RFID over bar code solutions is implementation. This is not just an inertia problem. The challenge is that RFID technology has a lot of functionality. More functionality means more “moving parts” and “flavors” with RFID than the “good old” bar code.
Implementing a RFID Versus Bar Code Solution.
Physical Implementation. Bar codes implementations do have physical environment challenges. These challenges include environment (hot, cold, wet, etc.), placement, and the label quality to assure that the bar codes are readable by the scanning devices. RFID tags have the same environmental challenges as bar codes, plus with RFID tags you have to choose the level of functionality you need for a given project.
RFID tags has several components and add-ons that can be added to the RFID tag depending on functionality required. Physically RFID tags can range in size from smaller than a grain of rice to bigger than a brick. The challenge is picking what flavor of RFID tag that you need such as active tag versus passive tag. There may be scores of different types of RFID tags to pick from based on cost and functionality for a given project.
Data Structure. Bar codes basically have two different data structures. The regular bar code and the 2d bar code. RFID tags can have a lot of different data structures plus they can have read-write capabilities. For simple RFID implementations, data on the RFID tag can just consist of an unique identifier. RFID standards for unique identifiers such as EPC are maturing, but these standards have a lot more implementation challenges than just slapping on a bar code with a stock number. More advanced RFID tags can store about any type of data. This can include product data, status data, event data, and so on. The evolving data standards and functionality for RFID can make for very complex data integration strategies.
Application Interfaces. The application interfaces for bar codes are fairly simple. There is usually a fixed number of data elements and there is usually a fixed number of events that an application needs to capture about the bar code. Examples of events include warehouse events (put-away, pick), shipping events (pick-up, delivery), retail store events (receipt, stock), and so on. With RFID tags there can be more complex event scenarios. Possible event scenarios can include things like do you just need to record simple events at chokepoints such as with bar codes, or do you need real-time location tracking? Additionally, the application may need to deal with data “wrappers” that are used to transport the RFID reads and writes that are coming over the RFID network. Depending on functionality the application may need to interact with the RFID network and RFID tags such as querying multiple tags for a given data element, writing to a tag, and so on. If the RFID tag has sensors, then this type of data needs to be handled as well. Questions come up on how much data to store on the tag versus how much data should be stored and shared by the application. RFID technology offers a lot of opportunities over bar codes, but application integration can be frustrating. The art of implementing a good RFID solution is maximizing functionality while keeping things simple.
The Air Interface. With bar codes communications, you just need to figure out what type of bar code scanner you need. With RFID technology there are a variety of RF frequencies that you can use depending on transmission distances and environmental considerations. These RFID air standards are starting to mature with ISO DASH7 standard for active tags and ISO standards for passive tags. Even though RFID communications does not require line-of-sight like bar code scanners, there are many communications challenges with RFID. This includes reading many RFID tags at the same time, wireless interference, and power requirements for RFID tags.
Business Requirements. Because RFID offers the promise of much more functionality than bar codes, the need for good business requirements is essential. You need to do your homework. There are a lot of choices and one-size-fits-all solution will not work with RFID technology. For a RFID project to succeed, you need to pick the right RFID tag, the right data structure, the right applications, the right RFID reader network, and the right wireless RF interface.
