Research On A High Gain CDMA-VSAT Transceiver And Its Networking

In this thesis, a new scheme of Ku band CDMA-VSAT network is presented, which is applied in GEO satellite and QS-CDMA techniques. The star and net hybrid topology network, composed of many low-cost compact VSAT terminals, Hub station and the network management center, can provide mobile satellite service (MSS), such as low rate voice and data services.Based upon the idea of software radio and the technique of non-coherent dispreading, DQPSK modulation and M-ray spreading spectrum, a new scheme of all-digital CDMA-VSAT transceiver with high gain is presented, which can provide two physical channels at the same time. And then a synchronizing and tracking loop employing swiveling correlation by means of matched filters, FFT and a two-dimensional maximum likelihood acquisition is also presented and analyzed, which can obtain a rapid acquisition and accurate frequency uncertainty estimation. Besides, a non-coherent digital delay lock loop (D-DLL) suited for chip timing synchronization and code tracking is introduced and discussed, which is helpful to lock the master clock from Hub station and realize master-slave network synchronization. Then the realization of this scheme based on FPGA and DSP is briefly discussed. Moreover, a signaling protocol model of this CDMA-VSAT network, in this thesis, is also presented. And radio resources management and call setup procedure starting from terminals or network is discussed. To meet the requirement of signaling transition with high reliability, a new data link protocol named LAPDV is proposed, which is developed from LAPD and LAPDm, and is more suitable for the low rate VSAT network. At the end of this thesis, the designing of signaling protocol software based on ARM embedded development platform is discussed.