基于复数生成对抗网络的5G OFDM信道估计方法

5G OFDM channel estimation method based on complexvalued generative adversarial network

准确的信道估计能够显著地降低误码率(bit error rate,BER),提高无线通信效率和质量,是5G OFDM通信系统接收机设计的关键环节之一。基于最小二乘(least square,LS)法和基于最小均方差(minimum mean square error,MMSE)的信道估计方法利用系统稀疏性计算信道响应矩阵,但LS算法计算精度较低,而MMSE算法计算量过大。为提升估计精度,业界设计了基于深度学习的信道估计方法。然而,现有的深度学习方法将复数矩阵拆分成实部和虚部,没有充分提取信道中的复数特征,造成估计的信道响应矩阵出现失真。为此,设计了一种基于复数的生成对抗网络模型,充分提取信号的复数特征,从而更准确地估计5G新空口(new radio,NR)标准的物理下行链路共享信道(physical downlink shared channel,PDSCH)的信道响应矩阵。为了验证所提方法的有效性,将所提方法分别与LS算法、实际信道估计、超分辨率神经网络、残差神经网络信道估计算法进行了对比分析。结果表明,当估计的信道响应矩阵与真实矩阵之间的均方差达到0.01时,采用所提方法实现的无线通信系统的信噪比高于现有方法5 dB左右。

Accurate channel estimation is a critical component in the design of 5G OFDM communication system re‐ceivers,since it can significantly reduce the bit error rate(BER),thus improving wireless communication efficiency and quality.Channel estimation methods based on least square(LS)and minimum mean square error(MMSE)effec‐tively utilize the system’ssparsity,but LS algorithms face low computational precision,while MMSE algorithms suf‐fer from high computational complexity.To promote the estimation accuracy,practitioners have presented several deep learning-based channel estimation methods.However,existing methods often split complex matrices into real and imaginary parts,failing to adequately capture the complex characteristics of the channel,leading to distortion in the estimated channel matrix.A complex-valued generative adversarial network(GAN)model that could fully extract the complex features of the signals was proposed,enabling accurate estimation of the channel matrix for the physical downlink shared channel(PDSCH)in the 5G new radio(NR)standard.To validate the effectiveness of the proposed method,the proposed method was compared with LS algorithms,actual channel estimation,super-resolution neural networks,and residual neural network channel estimation methods.Results show that when the mean square error be‐tween the estimated channel matrix and the true channel matrix is 0.01,the proposed method-based communication system has a signal-to-noise ratio(SNR)that is 5 dB higher than existing ones.