Research On The Design Of Multiple Zero Correlation Zone Sequence Sets

Zero correlation zone(ZCZ)sequence is a type of spreading sequence suitable for quasi-synchronous code division multiple access(QS-CDMA)systems.The level of the interference and the number of users of a communication system are limited by the correlation of the spreading sequences and the set size,respectively.Therefore,designing a sequence set with large set size and good correlation has important research significance for improving the anti-interference ability and increasing the number of users.This thesis mainly studies the methods of constructing multiple ZCZ sequence sets,which are suitable for multi-cell quasi-synchronous code division multiple access communication systems.Firstly,a method of optimal multiple polyphase ZCZ sequence sets with inter-set zero cross-correlation zone is proposed.The evaluation criteria of binary multiple ZCZ sequence sets by Tang et al.is extended to the polyphase sequence sets.And the evaluation criteria of multiple ZCZ polyphase sequence sets is established.Then,based on DFT matrices and finite field addition,a uniform method is proposed,and multiple ZCZ polyphase sequence sets with optimal parameters are obtained,which cannot be obtained by the existing methods.Secondly,a general method of multiple mutually orthogonal binary ZCZ sequence sets is proposed.The key of this method is the construction of mutually orthogonal complementary sequence sets.In this thesis,based on the nonrepeating frequency hopping sequence set with one coincidence,complementary sequences sets are constructed.Then,mutually orthogonal multiple binary ZCZ sequence sets are obtained.Compared with the existing methods,this method can obtain more binary ZCZ sequence sets,and the parameters reach the theoretical bound.Finally,a method of multiple binary ZCZ sequence sets with inter-set low correlation zone is proposed.The mutually orthogonal complementary sequence sets satisfying certain conditions are constructed by using the nonrepeating frequency hopping sequence set with 2-times coincidence and orthogonal matrices.Then binary ZCZ sequence sets with inter-set low correlation zone are constructed.Compared with the existing methods,this method can obtain binary ZCZ sequence sets with better inter-set low correlation property.