位屏蔽多叉树搜索射频识别防碰撞算法

针对RFID树型防碰撞算法中时隙数多、数据通行量大等问题，提出了一种改进的多叉树防碰撞算法，阅读器准确检测碰撞位并向标签反馈碰撞位信息，标签对阅读器已知的ID位进行屏蔽，把ID号转换成连续碰撞的序列号.阅读器利用屏蔽位信息和标签返回的碰撞位编码信息，对标签进行分层分类搜索.通过对标签ID进行屏蔽，阅读器和标签间仅发送对方不知道的碰撞位信息.该算法减少了碰撞时隙和识别时隙，避免了空闲时隙，减少了阅读器和标签间的数据通信量.理论分析和仿真结果表明，该算法减少了系统的时隙总数和数据通信量，提高了阅读器的识别效率.

A RFID Anti-Collision Algorithm Based on Bit-shield and Multi-tree Search

Focusing on the problem of multi slots and large amount of data traffic in RFID tree anti-collision algorithm,an improved anti-collision algorithm based on multi-tree is proposed.The reader can detect the collision accurately and send feedback to the tags regarding the collision bits information.The tag shields the known ID bits of the reader and converts the ID number into the serial number of consecutive collisions.The reader makes use of shield bits information and the collision bits coding information returned by the tags in order to search the tags in a hierarchical classified manner.By shielding the tag ID,the reader and the tag only sends the collision bits information which the other party unknown.The algorithm reduces the collision time slots and the recognition time slots,avoids the idle time slots,and reduces the communication data between the reader and the tags.Theoretical analysis and simulation results show that the algorithm reduces the total slots and data traffic,and improves the recognition efficiency of reader.