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感测发送者的位置的技术。该项目旨在开发一种使用有限长度 PN 序列的异步 CDMA 通信和位置传感系统。研究成果如下：(1)实值有限长度序列的研究针对该系统，开发了一种能够带来高传输效率的序列集。为了用户选择性地组建无线网络，研究了其他具有脉冲相关性的序列对，但传输效率稍低。(2)复用通信系统的开发开发了由长度为65的实值序列分配的4个用户的通信系统，从多速率数据中传输二值调制信号，并通过相关处理来解调数据，抑制干扰、噪声和幅度失真。该系统比OFDM系统（如地面电视系统所采用的）具有更高的频率使用效率和更强的幅度失真容忍度。（3）位置感测系统的开发是通过将发射天线和放置在三角形顶点的三个接收天线之间的距离差得出的双曲线相交来计算位置。检测到的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。所开发的用于检测拥有代码的人或物体并与每个人或物体进行通信的系统是一个建议。未来的主题是研究和开发实用的改进。

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.