Abstract: To avoid signal collision when more than one tag send the recognition information to the reader in tunnel personnel positioning system, a new anti-collision algorithm is proposed based on the binary search algorithm. The improved algorithm adopts the Back-strategy and removes the information redundancy bit in the paging procedure, thereby, reduces the number of collision and shortens the time of transmission. The analysis on the search times and transmission delay indicates that the probability of collision and transmission delay reduce greatly compared with the existing binary tree algorithms and dynamic binary search algorithms. It can effectively solve the multi-objective identification of anti-collision problem.

Key words: tunnel personnel positioning system, Radio Frequency Identification（RFID）, anti-collision algorithm, binary tree

摘要： 为防止隧道人员定位系统中多个射频标签同时向阅读器发送识别信息时产生的碰撞问题，在二进制搜索算法的基础上进行改进。改进算法采取后退策略，减少了碰撞发生次数；去除寻呼过程中的信息冗余位，缩短了数据传输的时间。通过对改进二进制树防碰撞算法搜索次数以及传输时延的分析表明，碰撞概率较二进制搜索算法及动态二进制算法大大降低，传输时延也减小，可以有效解决多目标识别的防碰撞问题。

关键词: 隧道人员定位系统, 射频识别（RFID）, 防碰撞, 二进制树