Abstract: A cross layer design of quickly tag reading scheme is proposed，which consists of two steps.At the reservation step，a two-dimensional access which combines slotted-ALOHA and orthogonal code reservation is adopted，and tag direction is estimated by the reservation code and antenna array on the reader.At the tag data reading step，the different spatial characters of the tags are employed to cancel the multiple tag interference(MTI) in the same slot.Simulation results show that tag reading speed is very high and it increases with code length and antenna number.

Key words: medium access control(MAC), collision, orthogonal code, antenna array, cross layer design, RFID

摘要： 提出一种基于跨层设计思想的高效标签读取方案，该方案由标签预约和标签数据传输两步组成。预约过程采用时隙-ALOHA和正交码预约相结合的码时二维接入方式，并利用预约码和阵列天线获取各个标签的空域特征；在数据传输过程，阅读器利用各个标签不同的空间特征将发生碰撞的数据分离开来。仿真结果表明，该方法大大提高了读取速度，且读取速度随天线数目以及码长的增加而增加。

关键词: 媒体接入控制(MAC), 碰撞, 正交码, 阵列天线, 跨层设计, RFID