Research And Realization Of Matched Filter And Orthogonal Variable Spreading Factor

Wideband CDMA is a technique used for wireless data transmission. Every mobile handset and every wireless base station operate on the same frequency spectrum. In order to discriminate one conversation from another, every handset broadcasts a unique code sequence. CDMA base stations must be able to discriminate these different code sequences in order to distinguish one transmission from another. This discrimination is accomplished by means of a matched filter, whose output indicates when a particular code sequence is detected in the input data stream.Wideband CDMA supports many kinds of services. These services have different data rate. Each service has its own spreading code. To prevent the interferences of different services, the spreading code is requested to have the orthogonal specification. Since the wideband after spreading is same to different services, it is necessary to take the orthogonal variable spreading factor (OVSF). Wideband CDMA uses this kind of spreading code.In this dissertation, matched filter and orthogonal variable spreading factor are investigated. In chapter 2, basic principles and architectures of matched fileter are analysised. Parallel matched filter and fold matched filter are put forward. This dissertation puts emphasis on the architecture which is suitable in FPGA. In chapter 3, Xilinx FPGAs are introduced first. Simulators based on FPGA are made, and HDL codes are listed partly. In chapter 4, characteristic of orthogonal variable spreading factor are studied. Distributive principle and estimate performance are analysised. In chapter 5, ALTERA FPGAs are recommended. Simulators based on FPGA for orthogonal variable spreading factor are made. Also ways of configurature of FPGA are discussed.