Constructions Of Multilength Optical Orthogonal Codes

Optical code division multiple access (OCDMA) technology is a spread spectrum communication technology, which allows multiple users to transmit information on the same broadband optical channel. It has advantages such as strong anti-interference, good secrecy and so on. It was first used in the field of military communications, and later was widely used in satellite, mobile and other communications. The construction and design of optical address code are one of the focal point of optical code division multiple access system. In 1989, Chung et al proposed the concept of one-dimensional optical orthogonal code (1-D OOC) which provided an effective method to construct optical address code. Subsequently, the study of optical orthogonal code has attracted the interest of many scholars at home and abroad, the research results are very rich. In recent years, in order to meet the demand of multimedia transmission with different signal rate and quality of service in the code division multiple access optical networks (such as digital, image and sound, etc.), research interest on optical orthogonal codes has been changing from the same length to multilength. In simple terms, a good correlation of MLOOCs is organic combination of a number of one-dimensional optical orthogonal codes with different lengths.In this paper, we focus on the optimization and combination construction of the optical orthogonal codes with the weight of three and enough small correlation function value. In the third chapter, we establish some new upper bounds of MLOOCs, which provide the evaluation criteria for the construction of optimal codes. In addition, many papers were investigated the optimal methods of construction and existence of ({n, nr}, M,3,1; 2) -MLOOCs when r= 1(mod 2). However, when r= 0(mod 2), the optimal structure of ({n, nr}, M,3,1; 2) - MLOOCs becomes very difficult, and relevant results are very little. In the fourth chapter, we will make use of the hole cyclic difference matrix and analyze the internal structure of the combined configuration to establish the construction method, and get some new optimal ({n,nr},M,3,1; 2) - MLOOCs, where r= 0(mod 2). In the fifth chapter, the construction methods and existence of optimal multilength optical orthogonal codes with three or more than three kinds of lengths are established.