Application Research Of SDR In The Mobile Terminal Based On TD-SCDMA

SDR (Software Defined Radio) defines that on the simple and general hardware platform, varies radio applications can be implemented by using the software which can be updated and reconfigured. SDR can make the wireless communication system have a good flexibility and generality. Also, the interlinkage and update of the system will be very convenient. China puts forward the TD-SCDMA (Time Division Synchronous Code Division Multiple Access) to the ITU as an spatial-interface standard of 3G. TD-SCDMA can substitute the UTRA-FDD and combine the advantage of CDMA ,TDMA and FDMA. Using the technology of TD-SCDMA, the communication system will have a bigger system capacity , the utilization factor of spectrum will be higher and the ability of anti-jamming will be enhanced.In this thesis, the application of SDR in the mobile terminal based on TD-SCDMA is studied. First, the structure of SDR and the physical-channel of TD-SCDMA are expounded, then software and hardware models of the terminal receiver, which use the SDR structure of wideband and bandpass sampling in IF (Intermediate frequency), are put forward. The design of hardware module includes A/D converter, DDC (Digital Down Converter) and DSP. The design and application of AD6640 and AD6624 are fully discussed in this part. The design of software module includes the parameter design for DDC filter and the baseband signal processing of DSP. And the realization of the Viterbi channel decoding algorithm by DSP and the simulation of the burst at the transmitter are discussed. The results of this thesis reveals that the application of SDR in 3G are reasonable. It can provide some reference worth to develop the application research of SDR.