A Novel Method for Parallel Decoding of Turbo Codes

Parallel decoding of turbo codes is vital to the applications with very high data rates. There are mainly two existing methods for the parallel decoding of turbo codes: one is to have the sub-blocks being overlapped (OL); the other is to store the intermediate information of last iteration at the sub-block boundary (SBI). The overlapping in OL methods will slow down the decoding speed while the SBI requires some extra memory. In this paper, we present a new method which is essentially the combination of the OL and SBI but with two new features being introduced: (1) instead of storing the full information of the boundary distribution as SBI does, the proposed method only stores the index of the most probable state at the boundary and a reliability metric for initialization; (2) the boundary positions of the sub-blocks are moving in each iteration of the turbo decoding process. The proposed method outperforms the existing methods and is flexible in design and implementation.