Dsss Communication System Design And DSP Implementation

Spread spectrum communication contains a lot of advantages there, including anti-interference ability, multipath, anti-interception, security and good, strong multiple access performance and high precision ranging, highly concerned about the increasing number of communications industry, modern society one of the most advanced wireless communications core technology. With the development of innovative DSP technology, so that the digital signal processing associated with the gradual application of research results in the actual project to promote the combination of engineering and theoretical research.In this thesis, the development process of the spread spectrum communication technology carried out detailed studies and in-depth study of the theory of spread spectrum communication techniques, and the consensus Shannon channel capacity is the basis of some of these theories, the common spread spectrum communication system of DS, FH, TH, Chirp and mixed linear pulse spreading system. This article describes in detail the historical development of spread spectrum communication technology, for direct sequence spread spectrum communication system to do a careful analysis and simulation, and taking into account the problems in practical engineering applications.In consideration of the project can be realized on the basis of direct sequence spread spectrum wireless communications system simulation link is based on m language and related library function MATLAB simulation platform, modular design is completed. DSSS contains two spreading factor, they are SF = 4 and SF = 128, and describe the role of each module. It includes initialization, the data transmission channel, data reception performance statistics module, and the framing mode data transmission link does not include the synchronization header, a payload and includes only a pilot field. Channel model including AWGN channel and multipath fading channel, Rake receiver is the goal in order to suppress multipath fading. DSSS communication link performance simulation and output simulation in AWGN, Rayleigh and channel Cost207 performance test results under different data transfer rates.DSSS includes software and hardware, taking into account the data characteristics and features of the system parameters DSP chip, using TI’s TMS320C6455 chip.Software framework used in this way the system is polling. If there are tasks to be created at initialization has been created, and it will be always running, when the whole system is powered down or reset, the life cycle of the task will be terminated.DSSS communications includes transmitter and receiver, and the ability to send and receive traffic data processing functions.the transmitter and receiver use the same hardware platform, loading specific software to send and receive data transmission capabilities, as defined in the system software signal processing software running on a DSP chip baseband processing module.