Convergence performance and EXIT analysis of 4-state partially-systematic Turbo codes

Abstract

The error-rate performance of punctured Turbo codes may be significantly improved by puncturing data symbols as well as parity symbols, yielding partially-systematic Turbo codes (PSTCs). In this paper, it is shown that relatively simple 4-state PSTCs are able to achieve convergence (i.e., waterfall) performance that is 0.26 dB from the binary channel capacity limit at rate 1/2 and 0.18 dB from the limit at rate 8/9. It is also demonstrated that extrinsic information transfer (EXIT) charts do not accurately predict convergence performance for 4-state PSTCs.

25 Years of Turbo Codes: From Mb/s to beyond 100 Gb/s

“…Periodic puncturing patterns are favoured thanks to the offered advantages ranging from a simplified design process to the low complexity hardware implementation. In [34], it was observed that the puncturing of well-chosen systematic bits can improve the performance of turbo codes at high and low error rates especially for high coding rates. Lately in [35], it was shown that the reliability of extrinsic information related to an information bit depends on the position of the considered bit in the puncturing period and the puncturing or not of the corresponding parity.…”

Protograph-Based Interleavers for Punctured Turbo Codes

“…As shown in [27], [28], the puncturing of well-chosen systematic bits can increase the d min value and reduce the convergence threshold of high coding rate TCs. Thus, in this work, we consider the design of puncturing masks including data puncturing.…”

“…In [28], the distribution of the extrinsic information in terms of log-likelihood ratios at the output of a soft-in soft-out (SISO) decoder was plotted and analyzed. It was shown that the distribution of the extrinsic information related to punctured data positions is different from the one related to unpunctured data positions.…”

Improving Turbo Codes for 5G with parity puncture-constrained interleavers

“…As shown in [15], the puncturing of well-chosen systematic bits can increase d min and reduce the convergence threshold of TCs. The selection of the systematic bits to be punctured must be performed carefully, in order to prevent the constituent codes of the TC from being affected by a catastrophic puncturing mask [3].…”

“…As pointed out in [15], conventional Extrinsic Information Transfer (EXIT) charts [16] are not appropriate to predict the convergence threshold of TCs with punctured data bits. Thus, an analysis of the real exchange of extrinsic information between the constituent Soft-In Soft-Out decoders, via uniform interleaving [17] within actual turbo decoding iterations, is carried out to select the best puncturing mask in terms of TC convergence.…”