Design And Realization Of Demodulation On IEEE 802.11b/a/g Modulation Signals

The thesis is concentrated on the design and realization of demodulation on DSSS,CCK,OFDM and PBCC about IEEE 802.11b/a/g modulation signals based on ?Research on Digital Modulation Signal Test and Analysis in Hybrid/Heterogeneous Network?,which belongs to the project of the national key scientific instrument and equipment development ?Research and Application Development on High Performance Spectrum Analyzer(Project ID: 2012YQ20022404)?.The main contents are as follows:1.The criterions of IEEE802.11b/a/g on physical layer are analyzed,and key technologies of demodulation for DSSS,CCK,OFDM and PBCC are investigated.Besides,the demodulation process of four kinds of signal reception are designed based on frame format of physical layer.Then the error parameters of the vector signal testing analyzer are analyzed and the formulas are given respectively.2.Algorithms of the demodulation,despreading,bit stream decision,channel decoding and descrambling about DSSS,CCK,OFDM and PBCC signals are designed and implemented.The demodulation algorithms include timing synchronization,carrier synchronization,channel estimation and equalization.For timing synchronization of OFDM,a delay signal auto-correlation is designed aiming at dealing with the peak fuzzy by comparing some existing typical timing synchronization algorithms,such as construction of a specific structure of the training sequence sliding auto-correlation detection,receiving training sequence and the local training sequence sliding cross correlation,etc.The verification results show that the algorithm can generate a single sharp correlation peak at the timing point,and implement the timing synchronization perfectly and the algorithm has low complexity.3.As for the practical application of the algorithm,the testing and analysis system for the DSSS,CCK,OFDM and PBCC is designed.The platform is constructed to test the system using real-testing data.Besides,Agilent 89600 software acts as a reference and is helpful for confirmation.The results show that the system designed can recover the constellation,and the calculated error parameters of the signals basically meet the requirements of the project indicators.Also,the performance is equivalent to Agilent 89600 sofware under the same conditions.