Abstract: The present invention relates to a decoding method of a software modem in a limited memory environment using overlapping fragmentation and progressive decoding, which processes packets in real-time and reduces power consumption in an environment in which memory is limited when the software modem is used, and the decoding method includes: (a) receiving a data packet from the signal processing device, by the software modem; (b) fragmenting the data packet, decoding the fragments by the fragment, and transferring a decoded MAC header to the MAC module, by the software modem; (c) analyzing the MAC header and verifying whether the packet is a data packet transmitted to the MAC module itself or the packet is damaged, by the MAC module; (d) directing, when the data packet is verified, the software modem to perform additional decoding on the data packet, by the MAC module; and (e) directing, when the data packet is not verified, the software modem to drop the data packet, by the MAC module.