Unknown RFID tags appear when tagged items are not scanned before being moved into a warehouse, which can even cause serious security issues. This paper studies the practically important problem of unknown tag detection. Existing solutions either require low-cost tags to perform complex operations or beget a long detection time. To this end, we propose the Collision-Seeking Detection (CSD) protocol, in which the server finds out a collision-seed to make massive known tags hash-collide in the last $N$ slots of a time frame with size $f$ . Thus, all the leading ${f-N}$ pre-empty slots become useful for detection of unknown tags. A challenging issue is that, computation cost for finding the collision-seed is very huge. Hence, we propose a supplementary protocol called Balanced Group Partition (BGP), which divides tag population into $n$ small groups. The group number $n$ is able to trade off between communication cost and computation cost. We also give theoretical analysis to investigate the parameters to ensure the required detection accuracy. The major advantages of our CSD+BGP are two-fold: (i) it only requires tags to perform lightweight operations, which are widely used in classical framed slotted Aloha algorithms. Thus, it is more suitable for low-cost tags; (ii) it is more time-efficient to detect the unknown tags. Simulation results reveal that CSD+BGP can ensure the required detection accuracy, meanwhile achieving $1.7\times $ speedup in the single-reader scenarios and $3.9\times $ speedup in the multi-reader scenarios than the state-of-the-art detection protocol.

中文翻译：

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快速，准确地检测RFID系统的未知标签–哈希冲突是可取的

如果在将标签物品移入仓库之前未对其进行扫描，则会出现未知的RFID标签，这甚至可能导致严重的安全问题。本文研究了未知标签检测的实际重要问题。现有的解决方案要么需要低成本标签来执行复杂的操作，要么需要较长的检测时间。为此，我们提出了碰撞寻找检测（CSD）协议，在该协议中，服务器找到一个碰撞种子，最后使大量已知标签发生哈希冲突 $ N $ 具有大小的时间范围内的广告位 $ f $ 。因此，所有领导 $ {fN} $ 空位对于检测未知标签很有用。一个具有挑战性的问题是，找到碰撞种子的计算成本非常高。因此，我们提出了一个称为平衡组分区（BGP）的补充协议，该协议将标签填充分为 $ n $ 小团体。组号 $ n $ 能够在通信成本和计算成本之间进行权衡。我们还提供理论分析以调查参数，以确保所需的检测精度。我们的CSD + BGP的主要优点有两个：（i）它只需要标签即可执行轻量级操作，而这些标签已广泛用于经典的帧时隙Aloha算法中。因此，它更适合于低成本标签；（ii）检测未知标签更加节省时间。仿真结果表明，CSD + BGP可以保证所需的检测精度，同时达到 $ 1.7 \次$ 单阅读器场景中的加速和 $ 3.9 \次$ 与最新的检测协议相比，在多阅读器场景中的速度更快。