The Design And Implementation Of Ad Hoc Physical Layer Based On Adaptive Modulation And Coding

Wireless Ad-Hoc is a kind of special peer-to-peer network. Using wireless communication technology, nodes in the network (the nodes in the scope of direct communication) in each other as its neighbors’routers, communicate through forward between nodes. In Ad Hoc network, to the question of the time-varying characteristic of wireless channel, using AMC and choosing the suitable modulation and coding mode according to the state of channel can ensure the quality of communication and improve the spectral efficiency at the same time. The nodes in the Ad Hoc as the research objects, we studied the design and application of the AMC system based on SC FDE.In this paper we proposed the design goal of AMC system and determine the overall architecture of the system based on Ad Hoc baseband system. Then, we analyzed the key technologies of the AMC system. To ensure the system can encode and decode Turbo in different rates, we researched and demonstrated the Turbo algorithm based on the rate matching, which can ensure the subsequent AMC algorithm. Also we deduced and proved the AMC algorithm adopting by the system, simulating through matlab&C, which can provide theoretical basis for subsequent FPGA implement. Results indicate that EESM mapping algorithm has a lower computational complexity and can improve the throughput of the system in the context of ensuring the error rate performance of the system. In the case of good channel condition, the throughput can be improved from5Mbit/s to20Mbit/s.Finally, we realized the FPGA in the AMC system. We achieved the module design of AMC system in the FPGA chips, including channel encode-decode module, constellation modulation-demodulation module, capture module, frequency domain equalization module, channel estimation and AMC control module. The results indicate that all the modules can work properly.