Fast Capture—Recapture Approach for Mitigating the Problem of Missing RFID Tags

Abstract

The technology of Radio Frequency IDentification (RFID) enables many applications that rely on passive, battery-less wireless devices. If a RFID reader needs to gather the ID from multiple tags in its range, then it needs to run an anti-collision protocol. Due to errors on the wireless link, a single reader session, which contains one full execution of the anti-collision protocol, may not be sufficient to retrieve the ID of all tags. This problem can be mitigated by running multiple, redundant reader sessions and use the statistical relationship between these sessions. On the other hand, each session is time-consuming and therefore the number of sessions should be kept minimal. We optimize the process of running multiple reader sessions, by allowing only some of the tags already discovered to reply in subsequent reader sessions. The estimation procedure is integrated with an actual tree-based anticollision protocol, and numerical results show that the reliable tag resolution algorithm attain high speed of protocol execution, while not sacrificing the reliability of the estimators used to assess the probability of missing tags.

Probabilistic optimal tree hopping for RFID identification

“…based on Equation (7). If (l, p) is the left child of its parent, then TH visits it if and only if the parent of (l, p) is a collision node.…”

“…Second, it assumes that the tag population remains static for the lifetime of tags as each tag is hard coded with some other tags' IDs. The second scheme is to run an identification protocol on the same population several times until probability of missing a tag falls below a threshold [7,10]. They estimate the probability of missing a tag based upon the number of tags that were identified in some runs of the protocol but not in others.…”

Who stole my cheese?: Verifying intactness of anonymous RFID systems

“…Existing work adopts 27 the latter toward scalability in large systems, falling into 28 two categories-probabilistic detection that detects the event 29 of absence with certain probability [9,11], and deterministic 30 identification that accurately pinpoints the IDs of absent tags 31 if any [10,[12][13][14][15][16]. 32 This paper aims to verify the intactness of anonymous 33 RFID systems without tag IDs as a priori (Section 2). Since tag 34 IDs usually contain object-specific information, we should 35 prevent such information from leakage when it is privacy 36 sensitive for tagged objects [6,17,18].…”

Channel-Aware Identification Protocol of Moving Tags in RFID Systems

“…However, how line codes are utilized is not presented in the specification. Moreover, if RFID tags have mobility, the received signals of tags vary by the movement of tags, and some tags may be out of the identification range of a reader before the tags are identified [10]- [12]. So a dynamic line code utilization mechanism is required due to the variation of the signal.…”