Wireless Ad Hoc network is a kind of peer-to-peer network.Due to its distinguishing characteristics such as:no control center,multi-hop,convenient network build-up,wireless Ad Hoc network is being rapidly applied in military field, natural calamity and remote area.Wireless Ad Hoc network is currently a research focus.The dissertation focuses on baseband research on backbone nodes which construct the Ad Hoc network.Firstly,the dissertation proposes the target of the baseband system and confirms the system architecture and some key parameters.OFDM can combat multipath fading and has high spectral utilization,so we use this technology in the baseband design.Secondly,the dissertation discusses some key points on baseband,which contain coding & decoding technology and synchronization technology.Through simulation, we find that the timing synchronization algorithm correlated with local sequence can get a good result.The simulation result proves that 1-bit correlator can be implemented in the timing synchronization.The baseband system has been simulated with Matlab,which can offer guidance for the followed FPGA implementation.Finally,the dissertation describes the hardware and FPGA implementation.The master controller in the baseband system is Virtex-4 FX60 FPGA,which controls a lot of devices,such as AD,DA,and DDR.Most functions of baseband system are realized with FPGA,including CRC coding and verify,scrambler,convolutional coding,Viterbi decoding,OFDM modulation and demodulation,timing synchronization and carrier synchronization.At last,the test result of the baseband system is proposed and the test result in FPGA is right.
