基于semi-bent函数正交序列集的构造

Constructions of Orthogonal Sets Using Semi-bent Functions

蜂窝技术在码分多址（code division multiple access,CDMA）系统中起着非常重要的作用.本文给出了用于构造CDMA规则蜂窝系统正交序列集的不同函数.首先,基于多输出semi-bent函数的性质,给出了一个构造编码长度为2~6的蜂窝系统.研究发现,通过选取不同的参数d（d∈{2,3}）,所构造蜂窝系统的蜂窝排列难易程度和重用距离可以相应的调整.其次,利用＂直和构造＂将semi-bent函数变元增加,进而得到编码长度为2~n（n≥6且为偶数）,重用距离D≥4的规则蜂窝系统.研究表明,所构造的蜂窝系统内,每个蜂窝所包含的正交序列个数达到了2^（n-2）（即与目前已知的最好结果相同）.

The cellular technology plays an important role in the code division multiple access（CDMA）system.In this paper,we present a different function for constructing orthogonal sequence set of CDMA system.Firstly,based on the properties of multi-dimension semi-bent function,we presented a cellular system with the code length of 2~6.By choosing different parameter d（d∈{2,3}）,we can assign the sets of orthogonal sequences to a regular tessellation of hexagonal cells more easily and adjust the re-use distance accordingly.Secondly,the number of variables of this semibent function increases by using direct sum construction and then a regular tessellation of hexagonal cells with the length of 2~n（n≥6,even）is obtained.It is showed that the number of users per cell reaches 2^（n-2）（which achieves the same as the best known results）.