Optical frequency combs (OFCs) generated in microresonators can substitute widely employed power-hungry laser arrays, ensuring spectral and energy efficiency in wavelength-division multiplexed passive optical networks (WDM-PONs). Here, we propose a realistic design of a WDM-PON based on a silica microresonator generating an OFC in the dissipative Kerr soliton regime and present a corresponding theoretical study, paying particular attention to the impact of a comb linewidth on the characteristics of the communication system. Using intensive numerical simulation, data transmission performance in 8-channel 100 GHz spaced WDM-PON is investigated for OFC carrier linewidths of 100 kHz, 1 MHz, 10 MHz, and 100 MHz. We show that microresonator-based OFCs with linewidths of up to 100 MHz can be used for non-return-to-zero on-off keying (NRZ-OOK) modulated data transmission system and give an acceptable bit error rate (BER). Results show that the narrower the linewidth, the lower the BER is. The data transmission results show that error-free data transmission is possible with a BER of 4.4×10-12 for 100 kHz OFC carrier linewidth, providing 80 Gbps of total data rate on eight OFC generated carriers.