An Energy and Identification Time Decreasing Procedure for Memoryless RFID Tag Anticollision Protocols

Up to date energy-aware radio frequency identification (RFID) anticollision protocols are mainly focused on RFID systems using active tags. The introduction of RFID in portable devices, and the increasing popularity of passive tags, demands low energy-consumption anticollision protocols in environments with passive tags. Memoryless protocols present the simplest tag hardware that is beneficial for a low energy consumption. However, the excessive collisions required by these protocols increases the energy consumption, wasting a large number of tag transmitting bits. In this paper, a window procedure is presented to manage the length of the tags' bit-stream in order to limit the energy wastage in collisions. The bit window is applied to two memoryless anticollision protocols, the query tree protocol (QT) and the collision tree protocol (CT), producing the query window tree protocol (QwT) and the collision window tree protocol (CwT). Simulations show that the use of this window yields significant reductions in energy consumption and identification time. In addition, QwT and CwT are compared to state of the art memoryless protocols to confirm that CwT is an outstanding candidate for reducing energy consumption. Also, the results obtained show how the bit window procedure increases energy savings as the length of the tag ID increases.