Design Of Vector Signal Demodulation In Software Radio Architecture

Digital communication becomes more popular owing to development of software radio technology.And there are many advantages in software realization of vector signal demodulation,such as saving resources and costs,shortening research period,extending and updating easily.This thesis analyzes demands for vector signal demodulation of multi-formats modulation,and realizes key algorithm modules described below by software.In the design of timing synchronization module,timing error estimation is completed using the amplitude leveling method,and a compensation algorithm based on a fractional interpolation filter is designed to achieve software timing synchronization.In the design of blind equalization module,the constant modulus and multi-modulus algorithms are selected for different modulation formats.The relevant parameters,gain control,equalizer iterative update and implementation flow are designed in detail,and the blind equalization software is realized.Phase-locked loop is applied to carrier recovery.Combining direct decision and polar judge algorithm,a carrier recovery algorithm for high order modulation is proposed,which acquires large frequency offset while small locked error.Samely,it is a specific software realization of carrier recovery at last.Frame synchronization module is achieved by external synchronization method.Three kinds of frame Synchronization code with corresponding detection and correction are designed.Finally a user-definable frame synchronization software is obtained.The thesis tests performance of vector signal demodulation software.Results show that for multi-formats,timing synchronization obtains accurate symbol points;blind equalization reduces channel interference effectively;carrier recovery captures frequencies offset from-1 MHz to 1 MHz;after frame synchronization,the BER of QPSK and 8PSK signal is reduced below 10^-7.After demodulating,the EVM of each modulation format is less than 10%?rms?.And the software,whose compatility is also evaluated,can analysis 400k symbols.