User-Identification Position-Sensing Asynchronous CDMA Communication System Using Finite-Length PN-Sequences

在自组织网络或传感器网络中，需要一种识别信号发送者并同时检测发送者位置的技术。本项目旨在开发一种基于有限长度伪随机序列的异步码分多址通信和位置检测系统。本文的研究成果如下：(1)实值有限长序列的研究针对该系统，提出了一种能带来高传输效率的序列集。为了便于用户选择性组网，研究了其他脉冲相关的序列对，使传输效率略有下降。(2)多路复用通信系统的研制利用长度为65的实值序列分配4个用户的通信系统，从多速率数据中传输二值调制信号，并通过相关处理实现对干扰、噪声和幅度失真抑制的数据的解调。该系统具有较高的频率利用率和较强的抗幅度失真能力(地面电视系统采用的)。(3)研制了一种位置传感系统，该系统利用一个发射天线与放置在三角形顶端的三个欺骗天线之间的距离差得到的双曲线相交来计算位置。检测位置的精度取决于天线之间的距离和系统时钟的时间间隔。提出了一种用于检测拥有代码的人或物体并与其进行通信的系统。未来的课题是研究和开发实用的改进措施。

In the ad hoc network or sensor network, a technique to identify a signal sender and simultaneously to sense the position of the sender is desired. This project aimed to develop an asynchronous CDMA communication and position-sensing system using finite-length PN sequences. The achievements of the research are as the followings.(1) Research on real-valued finite-length sequences For this system, a sequence set to bring high transmission efficiency has been developed. For user's selective formation of wireless network, other sequence pairs with impulsive correlation are investigated, to bring a little lower transmission efficiency.(2) Development of multiplexing communication system The communication system for 4 users allotted by real-valued sequences of length 65 has been developed to transmit two-valued modulated signal from multi-rate data and to demodulate the data with interference, noise and amplitude distortion suppressed through correlation processing. This system has high efficiency of frequency usage and the stronger tolerance with amplitude distortion than the OFDM system (as adopted to terrestrial TV system).(3) The position sensing system has been developed to calculate the position by intersecting the hyperbolas derived from distance differences between a transmitting antenna and three Deceiving antennas placed on the apex of a triangle. The accuracy of detected position depends on the distances between the antennas and on the time interval of system clock.The developed system for detecting the person or object possessing a code and communicating with each is a proposal. The future subject is the research and development of improvements for practical use.