Why queue up?: fast parallel search of RFID tags for multiple users

Abstract

Tag searching is a fundamental problem for a variety of radio frequency identification (RFID) applications. Prior works focus on single group searching, which refers to determining which ones in a given set of tags exist in the system. In this paper, we propose PTS, a protocol that can perform fast Parallel Tag Searching for multiple users simultaneously. Different from prior works that have to execute k times to search k groups separately, PTS obtains searching results for all the k groups with only one-shot execution. PTS achieves high parallelism due to some novel designs. First, we develop a grouping filter that encodes the membership of tags in different groups, with which non-target tags can be efficiently filtered out for all the k groups simultaneously. Second, we design two new codes, grouping code and mapping code, with which the remaining tags can quickly verify and confirm which group they belong to. We theoretically analyze how to set optimal parameters for PTS to minimize the execution time and conduct extensive simulation experiments to evaluate its performance. Compared with the state-of-the-art solutions, PTS significantly improves time efficiency in multiple group searching scenarios (by a factor of up to 7.54X when k = 10) and achieves the same time efficiency in single group searching scenarios.