Research On Designing Multi-Modulation Scheme Software Radio Receiver

The problem of modulation schemes are too many varieties to communicate between different systems exists in modern wireless communication systems. Multi-modulation scheme software radio receiver can solve this problem.This thesis is concerned with the study of designing multi-modulation scheme software radio receiver. Two mathematic models of software radio receiver are introduced and they provide theoretic basis for designing multi-modulation scheme software radio receiver. Considering DSP is the kernel of software radio receiver, the design process of DSP is discussed and it laid out system design wholly.Single-modulation scheme software radio receiver is designed by studying software design and hardware design. A universal and extendable hardware platform with the model of A/D-DDC-DSP was constructed, then DSP algorithms in software processing part are studied, of which the methodsof window design of FIR filter and a new FSK demodulation algorithm are discussed as an emphasis and their realizations on DSP chip are also provided in this paper. Experimental results showed that good effect was achieved by processing signal using these two algorithms.Automatic modulation scheme recognition is the bottleneck of designing multi-modulation scheme software radio receiver. An automatic modulation scheme recognition algorithm called modulation model is presented in this paper. According to transcendent knowledge, this algorithm classifies modulation systems by computing instantaneous frequency and instantaneous bandwidth of signal and regarding them as modulation parameters. Simulation results showed that this algorithm can recognize CW, FSK and PSK signal and it is robust and has good recognition rate.