摘要
Surface acoustic wave(SAW) tags are truly passive devices and do not contain any intelligence,so the question of multiple read in the reading range comes up.The paper suggests a Walsh matched-filtering method in Walsh field to distinguish the collision tags with a threshold.In advance,the code states with special sequency are selected from large possible states and the sequency variables of these tags are saved in a database.When a few tags are read simultaneously in read range,the received signal is filtered by the known sequency of single tag in database,and then these tags can be distinguished by the filtered result.Proper threshold selection improves operation speed.Experiment proves that this method is useful and reliable.
Surface acoustic wave （SAW） tags are truly passive devices and do not contain any intelligence, so the question of multiple read in the reading range comes up. The paper suggests a Walsh matched-filtering method in Walsh field to distinguish the collision tags with a threshold. In advance, the code states with special sequency are selected from large possible states and the sequency variables of these tags are saved in a database. When a few tags are read simultaneously in read range, the received signal is filtered by the known sequency of single tag in database, and then these tags can be distinguished by the filtered result. Proper threshold selection improves operation speed. Experiment proves that this method is useful and reliable.
基金
the National Natural Science Foundation of China (Nos. 10304012 and 50875167)
关键词
沃尔什
标签
阈值
声表面波
匹配
碰撞
滤波
过滤方法
surface acoustic wave （SAW） tag, Walsh matched filtering, multiple access
