| 3. | In the third chapter , the properties of the bipolar sequence are analyzed firstly . the auto - correlation , the cross - correlation and the accommodation of simultaneous users under given bit error rate between the bipolar codes and unipolar codes are compared . the conclusion is that bipolar codes have better auto - correlation and cross - correlation , and the system that uses bipolar codes can accommodate more users and simultaneous users 通过对其性质的总结,自相关曲线、互相关曲线的对比,以及在规定误码率条件下,使用双极性序列的系统与使用光正交码的系统之间的同时用户数比较,得出以下结论,双极性系统较之单极性系统具有更好的自相关、互相关函数,码字容量更大,使用双极性序列的ocdma系统在规定误码率条件下的同时用户数比使用单极性序列的系统要多得多,双极性序列完全适用于ocdma系统。 |