基于搜索算法的前传Delta-Sigma调制器优化设计

Optimal Design of Mobile Fronthaul Delta-Sigma Modulator based on Search Algorithm

针对目前移动前传中使用的通用公共无线电接口(CPRI)技术频谱效率不高的问题,文章提出使用Delta-Sigma调制(DSM)技术作为一种新的前传接口。另外,针对高阶稳定Delta-Sigma调制器参数搜寻中计算复杂度过高问题,使用遗传算法对所使用的四阶Delta-Sigma调制器的结构参数进行了搜索优化,并将该优化结构参数下的仿真结果与原结构参数下的仿真结果进行了比较。在1 bit量化的情况下,使用优化参数的Delta-Sigma调制器增大系统传输容量的同时,平均误差向量幅度(EVM)从0.031下降到0.028;在2 bit量化的情况下,平均EVM从0.013下降到0.011。

The Common Public Radio Interface(CPRI)used in mobile fronthaul has low spectrum efficiency.In this paper,we propose to use Delta-Sigma Modulation(DSM)technology as a new fronthaul interface.In addition,to solve the problem of high computational complexity in the parameter searching of high-order stable Delta-Sigma modulator,Genetic Algorithm(GA)is used to search and optimize the structural parameters of the fourth-order Delta-Sigma modulator.The simulation results under the optimized structural parameters are compared with those under the original structural parameters.Under the condition of 1 bit quantization,the Delta-Sigma modulator with optimized parameters increases the transmission capacity of the system while the average Error Vector Magnitude(EVM)decreases from 0.031 to 0.028.In the case of 2 bit quantization,the average EVM decreases from 0.013 to 0.011.