ASIC芯片上的载波恢复DSP算法设计与实现

The Design and Implementation of Carrier Recovery DSP Algorithm on ASIC Chip

针对第十七届中国研究生数学建模A题展开研究,对ASIC芯片上的载波恢复DSP算法设计与实现进行分析和建模.首先对光纤通信系统进行建模,根据模型选取了基于判决反馈的载波恢复算法,此算法可以在极小的导频开销下满足RSNR代价小于0.3dB的要求;其次在一定的线宽值和色散值范围内对色散、线宽与导频开销之间的关系进行了定性分析与定量仿真.结果表明,色散值与线宽值越大,满足RSNR代价的要求所需的导频开销就越大,近似满足线宽增大10倍,导频开销需增大8倍的规律;再次,设计了基于CORDIC算法的硬件实现方案,并给出了片上资源消耗分析,综合考虑性能和资源后,选取了位宽为8位的方案;最后,建立基于性能与资源的综合代价函数,通过优化算法确立最优方案.结果表明此算法可以根据传输距离,自动给出满足系统性能的量化位宽、导频长度和导频开销,同时可通过对权系数的调节给出不同需求下的方案设计.

According to A question in 17th National Graduate Mathmatical Contest,this paper aims at the study and modeling the design and implementation of carrier recovery DSP algorithm on ASIC chip.Firstly,the model of optical fiber communication system is established,and the carrier recovery algorithm based on decision feedback is selected.This algorithm can meet the requirement that RSNR cost is less than 0.3dB with minimal pilot cost;Secondly,within a certain range of linewidth and dispersion,the relationship among dispersion,linewidth and pilot cost is analyzed and simulated quantitatively.The results show that the larger the dispersion value and linewidth value are,the larger the pilot cost is required to meet the RSNR cost requirement.The results also show that the linewidth increases by 10 times and the pilot cost increases by 8 times;Thirdly,the hardware implementation scheme based on CORDIC algorithm is designed,and the on-chip resource consumption analysis is given.After considering the performance and resources,the scheme with 8-bit width is selected;Finally,the comprehensive cost function based on performance and resources is established,and the optimal scheme is determined by optimization algorithm.The results show that this algorithm can automatically give the quantization bit width,pilot length and pilot cost to meet the system performance according to the transmission distance,and can give the scheme design under different requirements by adjusting the weight coefficient.