DBL-CDMA互补地址码及其设计方法

DBL-CDMA complementary access codes and its designing method

为了增加扩频通信系统的码字数量并且降低系统的多址干扰和符号间干扰,将地址码设计与多用户检测结合,设计了DBL-CDMA(Daoben Labs code division multiple access)互补地址码。理论分析和仿真结果表明,DBL-CDMA地址码码字的自相关值以及该码字与几个可用码字间的互相关值仅在几个时间偏移处有附峰;该码字与其他可用码字的互相关值有大的零相关窗(zero correlation window,ZCW)。多用户检测只着重对相关有附峰的码字检测,降低了多用户检测的复杂度。相对于同样长度的LS(loosely synchronous)码,DBL-CDMA互补地址码大幅增加了可用的码字数量和每个码字的理想互补码的数目,扩展了码字间的ZCW。

Daoben Labs code division multiple access （DBL-CDMA） codes using multiple access codes with multi-user detection were constructed to increase the number of access codes for spread spectrum communication and to reduce inter-symbol interference and multiple access interference, A general scheme was presented for generating these DBL-CDMA codes, Since the autocorrelation and crosscorrelation functions only include a few side lobes in time shifts, the DBL-CDMA codes remarkably reduce the complexity of multi-user detectors. Compared with basic loosely synchronous （LS） codes with a fixed code length, the DBL CDMA complementary access codes not only significantly increase the number of available codes and the perfect complementary pairs, but also extend the minimum zero correlation window （ZCW）. Computer simulations verify the validity of the new codes,