A Novel Cross Layer Anti-Collision Algorithm for Slotted ALOHA-Based UHF RFID Systems

Abstract

Reducing collisions in UHF RFID systems is a crucial problem. In most anti-collision designs, the reader has to estimate the number of tags within its reading range during the interrogation process. Most of the approaches estimate the number of tags with observations in multiple time slots. Since estimation error varies along with the initial frame length and the number of tags, system efficiency is affected by both of them. To reduce the sensitiveness to them and improve system efficiency, we propose a novel MAC-PHY crosslayer anti-collision algorithm based on Bayesian inference. Specifically, each frame is allowed to end at an early stage and a slot-by-slot estimator is proposed. Benefit from its slot-by-slot nature, system efficiency is more stable and independent on the initial frame length and very close to the upper bound of dynamic framed slotted ALOHA (DFSA) algorithm. The performance of the proposed method is compared with the stateof-the-art algorithms through numeric simulations. The results show that the proposed solution significantly outperforms the compared ones. INDEX TERMS Anti-collision, Bayesian estimate, cross-layer, UHF RFID.

Grouping based radio frequency identification anti-collision protocols for dense internet of things application

“…In the current tag number estimation algorithm, the RFID reader does not have prior knowledge of tag number before the actual process of identification and relies on querying the tags within its read range and estimating tag number using the number of collision slots from the query result. The current estimation algorithm is based on an assumption that a collision means two tags have collided [14]. The equation ( 1) is the lower bound of collision slot-based tag number estimation which assumes that every collision slot means two tags have collided.…”

“…The fuzzy membership degree 𝑢 𝑖𝑘 can be computed for each tag using (12) while the centroid is computed using (13). The objective function is stated in (14):…”

A RFID-Integrated Framework for Tag Anti-Collision in UAV-Aided VANETs

“…By using the secant iterative method, Gao et al in [27] proposed an aloha-based anti-collision scheme, which could effectively estimate the number of tags. Moreover, by taking Bayesian inference into account, the cross-layer tag anti-collision scheme was investigated in [28,29], which could achieve optimal identification efficiency. Furthermore, the researchers in [30][31][32] considered multi-reader deployment to solve the mobile tag identification problem.…”

“…First, the proposed RFID-integrated UAVaided networks in [11][12][13][14][15][16][17][18][19][20][21][22][23] consider the flexibility of UAVs but ignore the characteristics of the dense RFID environment, such as the adaptive power control for the reader. Moreover, the designed tag anti-collision schemes in [27][28][29][30][31][32] are usually based on the conventional single frequency tags, which leave multifrequency tags out of consideration.…”

Adaptive Transmission Repetition and Combining in Bistatic WiFi Backscatter Communications

“…In practical deployment scenarios, there may exist contention and collision issues in two cases: (1) between tags (inter-tag case); (2) with other non-carrier WiFi signals. There have been a number of proposals to resolve contention between multiple RFID tags [22]- [25]. Some attempts have also been made for ambient backscatter communication [2], [26].…”