The Research On Synchronization Technology And Implementation Of Processing Platform Of Adhoc Network

AdHoc network is a research hotspot in present information technology field. Synthesizing the embedded computation technology, distributional information exchanging technology and wireless communication technology, AdHoc is a novel technology in information exchanging, processing and transmitting, which has the widespread application prospect and the huge application value.On the basis of a special burst-mode DSSS AdHoc system, a symbol timing synchronization algorithm and its implement are presented by correlating the received signals with the known preamble sequences. Especially, the forward frequency-offset fast estimation algorithm is studied, and a low-complexity forward frequency-offset fast estimation algorithm is given, which is realized in FPGA. The hardware platform of the AdHoc terminal is designed and implemented. The contents are composed of the following five aspects:Firstly, Based on the analysis of signal characteristics, transmission mechanisms, key techniques of the AdHoc, the article provides an realization scheme, which is applicable to the base band communication in this burst transmission mode; the special characteristic of QDPSK demodulation and frequency-offset compensation is analyzed. The carrier frequency-offset signal is calculated also for QDPSK signal.Secondly, According to the characteristics of the burst communication. A symbol timing synchronization algorithm and its implement are analyzed by correlating the received signals with the known preamble sequences. The functional test show that the timing synchronization module has a better performance, the algorithm can be used in the AdHoc burst transmission.Thirdly, The Carrier Synchronization is especially focused in this reference. Planning the estimation performance and engineering realization as a whole, a forward low complexity frequency-offset estimation fast algorithm(LFE) based on pilot symbols which has been proposed, the estimator is deduced in detail. The carrier frequency-offset signal is calculated also by the estimator. The number of computations and complexity decreased. The computer simulation results show that it has better performance in lower SNR.And then, On the basis of SFE algorithm before-analyzed, the realization scheme of LFEalgorithm has been given with the principle of module design. The module is tested in the real transmission system, the result shows that the frequency-offset module has better performance with lower on-chip resource.Finally, According to the system technologies needs, the hardware scheme of the AdHoc terminal is designed. The choosing ICs and designing circuit schematic are introduced detailedly, designing PCB and debugging of the hardware platform are also completed. It gives the result that the design of scheme and algorithm of system, the design of FPGA and PCB are effective and feasible in the real communication system.