Research On Application Of LDPC - DFT - S - OFDM Coding Modulation In Broadband WSN

Wireless sensor network is a combination of perception, compute and wireless communication. It can be widely used in intelligent transportation, environmental monitoring, wildlife protection and other fields and It is one of the most important applied technology in the twenty-first century. However, the current study focused on its key technologies, such as the node energy saving, positioning method and other key technologies. They have ignored the study of wireless sensor network broadband and anti-interference new method. It will greatly affect and limit the higher level application of wireless sensor networks.Taking video, image transmission in urban and forest environments and other broadband applications of wireless sensor network as the background, this paper deeply analyzes the channel transmission characteristics and compares it with LTE SCME model, concluding that the existing SCME EPA model and parameter configuration are suitable for WSN channel transmission in urban and forest environments. Under this model, the performance of the LDPC-DFT-S-OFDM code modulation combination is analyzed and researched, and then the baseband model of the combination is established. The new channel estimation algorithm that is suitable for the combination is proposed, and the related parameter allocation strategy is given. In the SCME EPA channel model and the given parameter configurations case, the simulation shows that the proposed channel estimation algorithm is feasible. The symbol error rate performance of the LDPC-DFT-S-OFDM scheme is simulated and analyzed. The LDPC-DFT-S-OFDM and the existing mainstream modulation methods that is chip mapping-OQPSK scheme are compared.Simulation analysis and theoretical analysis results show that the loss of the signal to noise ratio of the new algorithm is less than 1dB.But the new algorithm can greatly reduce complexity of channel estimation and storage space that channel estimation takes up. LDPC-DFT-S-OFDM code modulation combination has the flexible parameter configuration, flexible bandwidth configuration, low peak power ratio, simple and efficient decoding and other notable features in urban and forest multipath environments, so it can meet a variety of transmission requirements of wireless sensor networks. Compared with the existing mainstream modulation scheme, this combination can not only enhance the bandwidth, but also has strong anti-interference ability. So the information can be quickly and reliably transferred and the wireless sensor networks can be widely used.