Design And Implementation Of Industry Specific WMN Physical Layer

Wireless Mesh networks(Wireless Mesh Networks,WMN),as a new type of wireless access networks,has become a research and application hot spot in the fields of industrial and agricultural production,emergency command and dispatch and military in recent years because of its advantages of convenient and quick deployment,low cost,wide coverage and strong extensibility.The physical layer of wireless Mesh networks is the foundation of network system implementation.Its design quality directly affects the performance of the entire network system.In this paper,some key technologies used in WMN physical layer,such as orthogonal frequency division multiplexing,channel codec,synchronization,constellation mapping of QAM modulation,are summarized.The physical layer key technologies of LTE(Long Term Evolution,long term evolution)and IEEE802.16 are mainly introduced.For IEEE802.16,we focus on research and analysis of the Mesh frame structure given in its protocol.For LTE,the design of its OFDM symbols,randomization,channel codec(biter convolutional code and Turbo code),interleaving,constellation mapping,synchronization,etc.are discussed deeply.With a view to the practical application,based on the key technology of the physical layer above,the design scheme of the WMN physical layer is given in combination with the implementation method proposed by the LTE protocol and the physical layer of the IEEE802.16 protocol.The main design contents include frame structure(control sub-frame and data sub-frame),OFDM symbol,pilot,channel codec,inter-leaver,modulation and demodulation,synchronization and channel estimation.Two design sections of the WMN physical layer scheme are simulated which are synchronization and channel estimation.For PSS synchronization algorithm and preamble synchronization algorithm,the root mean square error(RMSE)of synchronous deviation with different signal to noise ratio under different channel models are given respectively.For channel estimation,the mean square error(MSE)between the estimated value and the true value of two different interpolation methods(Spline and linear)in the channel estimation under different channels are given.The simulation results verify the feasibility of the proposed scheme.