Design And Implement In Burst Communication Of Low SNR And Short Preamble

Burst signals has attracted more and more attention because of the characteristics of concealment and short-time. However, due to the mutual independence between frame to frame of burst signal, the receiver needs to estimate parameters of each frame signal before demodulation. So quick burst signal detection and synchronization has become the focus of research in this realm. This paper designed and implemented a burst communication receiver applied in low SNR conditions and short preamble.In this paper, we established detection and synchronization module in burst communication using Matlab. Methods of simulation comparison have been applied in the detection part. The detective methods of energy detection, correlation method and higher order cumulants have been tested in this module. Matlab simulation results show that the correlation method does not meet the target requirements due to short preamble and frequency offset in the low SNR condition. When Es/No= 2dB,the high order cumulants can not meet the miss detection possibility requirements of 10-4 which given in the paper.However energy detection still meet the requirements. Therefore, this paper selected as the energy detection signal acquisition algorithm. In synchronous part, Matlab simulations results estimated accurately the starting point of the signal by using joint frame synchronization and coarse frequency offset estimation algorithm, and improved the accuracy of frequency offset range. A large deviation correction of 30KHz has been realized with the subsequent fine CFO. In the timing synchronization, we can accurately estimate (0-3)T (sampling period) random value by O&M estimation algorithm which has no correlation with carrier frequency offset and phase offset. In the simulation of interpolation filter, linear interpolation and cubic interpolation can accurately correct the timing error. Taking into account the difficulty of algorithm and hardware implement, linear interpolation was chosen to complete the timing error correction. This paper proposed the choice of V&V algorithm in implement of phase offset estimation, which can correct any errors in the value from-π/4 to π/4. Finally, simulation to the overall receiver module has been completed and the whole module performance fully meet the requirements.Next program, each module was realized using VHDL in Quartus II and specific test programs will be listed as follows. Great performance has been obtained in hardware test on the DE2-115 and good matches of requirement in various SNR conditions.The burst communication receiver which designed in this paper can be applied not only to low SNR burst communication, but also to other non-cooperative communication systems. Great value will be embodied in emergency communications systems and military communications systems.