In the article the authors suggested a technique for "Estimating Satellite and Receiver Differential Code Bias". While the problem of DCB estimation is important enough it is difficult to find what new was done in the article. The authors used well-known approach based on spherical harmonics (SH), which was suggested by S. Schaer et al. (1998). Similar approach based on SH was used for M_DCB: MATLAB code by Jin et al. (2012). Recently a lot of article have been published containing new results on DCB and DCB estimation, for example applying convolution algorithm (Q. Li et al., 2018 ), applying SH along with trigonometric series (Z. Li et al., 2015), applying spherical cap harmonic for regional modeling (Liu et al., 2010), using combination of Minimum scalloping/Least squares/ Zero TEC method (Rideout & Coster, 2006), as well as indicating problems and solution for Compass/Beidou DCB (Z. Li et al.,