Multi-mode message passing switch networks applied for QC-LDPC decoder

The multi-mode message passing switch networks for multi-standard QC-LDPC decoder are presented. An enhanced self-routing switch network with only one barrel shifter permutation structure and a shifter-based two-way duplicated switch network are proposed to support 19 and 3 different sub-matrices defined in IEEE 802.16e and IEEE 802.11n. These proposed switch networks can route the decoding message in parallel by different sizes without signal congestion. The enhanced self-routing switch network can switch the messages at different expansion factors with the lowest hardware complexity. Under the condition of a smaller expansion factor, the decoder throughput can be enhanced from the two-way duplicated switch network by increasing the parallelism. In the 130nm CMOS synthesis result, the proposed enhanced self-routing and the two-way duplicated switch network gate counts are 21.9k and 37.4k at 384MHz operation frequency.