What is an error correcting code?
In the IT world error correction algorithms have been commonly used to reduce bit error rates. These proven techniques are ineffective in the RFID world primarily due to perturbations or the radio. The strength of a radio wave at a given location and at a given time is a statistical phenomenon. If a deep fade in signal occurs while a tag is being activated or responding, the data will be incomplete or corrupted. The reader illogic is sophisticated and discounts the tag response and issues a new tag read command. The process is continually repeated while the tag is in the field of view. Generation 1 tags are more susceptible to this phenomenon due to the longer time required to utilize the sorting algorithms in an effort to identify a single tag in a given population of tags. Generation 2 tags verify a solid communications link by exchanging a smaller random number with the reader prior to the tag delivering the actual encoded information.
