High-efficiency processing schedule for parallel turbo decoders using QPP interleaver

Cheng Chi Wong*, Hsie-Chia Chang

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

This paper presents a high-efficiency parallel architecture for a turbo decoder using a quadratic permutation polynomial (QPP) interleaver. Conventionally, two half-iterations for different component codewords alternate during the decoding flow. Due to the initialization calculation and pipeline delays in every half-iteration, the functional units in turbo decoders will be idle for several cycles. This inactive period will degrade throughput, especially for small blocks or high parallelism. To resolve this issue, we impose several constraints on the QPP interleaver and rearrange the processing schedule; then the following half-iteration can be executed before the completion of the current half-iteration. Thus, it can eliminate the idle cycles and increase the efficiency of functional units. Based on this modified schedule with 100% efficiency, a parallel turbo decoder which contains 32 radix-2 4 SISO decoders is implemented with 90 nm technology to achieve 1.4 Gb/s while decoding size-4096 blocks for 8 iterations.

Original languageEnglish
Article number5696787
Pages (from-to)1412-1420
Number of pages9
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Volume58
Issue number6
DOIs
StatePublished - 8 Jun 2011

Keywords

  • Parallel turbo decoder and quadratic permutation polynomial (QPP) interleaver

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