Low density parity check (LDPC) code is a widely used error correcting code in various applications such as Wi-Fi, Wi-Max and Digital Video Broadcasting — Satellite — Second Generation (DVB-S2). Proposed work is focused on LDPC decoder design using soft decision iterative message passing for a code length 222 bits, 546 bits, 642 bits, 648 bits and 1152 bits that gives BER of 10−5 with coding gain of approximately 4 dB. Proposed work shows fully parallel design on isolated shifted identity matrices based on structured construction quasi cyclic low density parity check code (QC-LDPC) that give throughput of 2 Gbps.