Research Of Software Radio Based On Digital Radio Mondiale Receiver

Software radio is first introduced in 1992 by USA and it is a new architecture for wireless communication. It is a wireless technology that uses software to realize the physical link. The basic idea is let the hardware as common platform, put more and more wireless arithmetic and personal function to software platform. So the developing of new wireless system and new wireless production will transform to software design, and the value of wireless communication will appearance in software development. This is the third revolution after fixed to mobile and analogy to digital transform.The ideal case of software radio is transform the signal from antenna or IF signal to digital using high performance A/D apparatus, and then send to personal terminal. The software terminal can receive different mode signal by using different program in the same platform. But most of system for common people is more complex than the ability of current integer ciruit(IC) for software realization, so this is just a good dream for us.In this way, how to design a good software system, how to depart the software from hardware and how to design a high performance DSP become the key technology in software radio. According to the ability of current DSP This thesis study a case for digital Radio mondial(DRM) system. DRM is developed to solve the analogy radio's shortcoming. OFDM is adopted in global standard-DRM. This thesis is based on the work on China 863 program -32 bits digital signal processor design for SOC and discussed the software design in DRM system. This paper first research the electric wave circumstance in radio frequency band. Comparing different existing system for digital radio. Combining the several OFDM synchronized schemes and taking the special frame architecture into accord, the paper gives a complete frequency, time synchornize method that using 3 steps- coarse, fine estimation and track.Study the software architecture for DRM system, show a software receiver that combing multi-mode(analyog,digit) and mult-band(AM,FM).Analyse the main receiving algorithm-FFT, channel estimation and so on and the characteristic of those algorithm.The complexity of those is also discussed. In order to improve the DSP performance, some special instruc-tions(CORDIC,ACS) fit wireless communication process is adopted through algorithm/architecture Co-design.Optimize three key units in DSP that used in software radio, parallel execution of bypassing unit(BPU) with instruction decode(ID) in architecture level and transform serial select with priority to parallel execution are applied to reduce time delay. Separate the center control to some small disperse control units and decrease the main signal's drive by sorting all interface registers into small ones to optimize the original pipeline control unit. Adopting redundant binary representation algorithm to transform the serial adder to parllel one that used in multiply-add instruction(MAC) to reduce delay. Reduce the original four stages pipline exection to three stages.