Effect of mobility on RFID reader-to-reader interference

In an RFID network, the signal transmitted by a reader to query tags may interfere with the communication of other surrounding readers. As a consequence, the readers are not able to detect the weak reply from tags. The reader-to-reader interference affects readers located within a given distance, called interference range. This phenomenon can be estimated when deploying an RFID system, because the initial positions of the readers are known. It is also possible to completely avoid it by placing the readers far enough each other. However, if the readers are mobile, the distances among readers change and the probability of reader-to-reader interference dramatically increases. A theoretical analysis is conducted in this paper in order to estimate the probability of interference among static and mobile readers. The random waypoint model, one of the most common mobility models, is adopted to describe the movements of the readers. The theoretical results are validated with simulations.