Low-Complexity Multi-Size Circular-Shift Network for 5G New Radio LDPC Decoders

This paper presents a low-complexity multi-size circular-shift network (MCSN) structure for 5th-generation (5G) New Radio (NR) quasi-cyclic low-density parity-check (QC-LDPC) decoders. In particular, a fine-coarse approach-based multi-size cyclic shift network, which decomposes the cyclic shift size into fine part and coarse part, is introduced. The proposed MCSN structure is composed of a pre-rotator performing the fine part of the cyclic shift, and a main rotator executing the coarse part of the cyclic shift. In addition, a forward routing circular-shift (FRCS) network, which is based on the barrel shifter and the forward routing process is presented. The proposed switch network is able to support all 51 different submatrix sizes as defined in the 5G NR standard through an efficient forward routing switch network and help reduce the hardware complexity using a cyclic shift size decomposition method. The proposed MCSN is analyzed, and indicates a substantial reduction in the hardware complexity. The experimental results on TSMC 65-nm CMOS technology show that the proposed MCSN structure for 5G NR LDPC decoder offers an area saving up to 56.75% compared to related works in the literature.