CDMA Communication System with Chirp Signal Carrier

本研究提出以扫频信号Chirp作为载波的系统。该系统的特点是不需要与接收机建立复杂的码同步系统，并且利用线性调频载波改善了CDMA系统中一个重要的相关特性。相关特性的分析是重要的，对该系统的评估也是通过计算机仿真的方法对CDMA多址性能的评估做相关特性的分析。通常，CDMA的多址接入取决于同时使用的PN序列的自相关和互相关特性。然而，当优先考虑接入性能时，具有好的相关特性的PN序列将使用具有差的特性的PN序列，因为它很少。在传统的DS-CDMA中，载波不影响相关特性。然而，在使用线性调频脉冲载波的系统中，由于不同频率的载波被乘以每个码片，因此相关特性根据线性调频脉冲载波的参数而变好或变坏。本文指出，当弄清相关特性参数与线性调频载波的关系，并采用相关特性特别差的PN序列时，多址接入性能得到改善。在本报告中，报告了这些结果，并且作为基本材料描述了关于线性调频信号的基本内容。

In this research, it proposes the system that uses the chirp signal that is the frequency sweep signal for carrier. The feature of the proposed system doesn't need the complex code synchronous system with the receiver, and, in addition, it achieved to be improved for an important correlation characteristic by chirp carrier in CDMA. The analysis of the correlation characteristic is important, and the evaluation of this system also does the correlation characteristic to the evaluation of the multiple access performance of CDMA by the computer simulation. In general, the multiple access of CDMA is decided depending on auto-correlation and the cross-correlation characteristic of the PN sequence used at the same time. However, the PN sequence with a good correlation characteristic will use the PN sequence with a bad characteristic when giving priority to the access performance because it is few. Carrier doesn't affect the correlation characteristic in conventional DS-CDMA. However, the correlation characteristic changes for better or worse, depending on the parameter of chirp carrier because carrier of a different frequency is multiplied to each chip in this system that uses chirp carrier. This report shows that the multiple access is improved when the relation of the parameter of the correlation characteristic and chirp carrier is clarified, and the PN sequence with an especially bad correlation characteristic is used. In this report, it reports on these results, and a basic content concerning the chirp signal is described as basic material.