Information-Coupled Turbo Codes for LTE Systems

We propose a new class of information-coupled (IC) Turbo codes to improve the transport block (TB) error rate performance for long-term evolution (LTE) systems, while keeping the hybrid automatic repeat request protocol and the Turbo decoder for each code block (CB) unchanged. In the proposed codes, every two consecutive CBs in a TB are coupled together by sharing a few common information bits. We propose a feed-forward and feed-back decoding scheme and a windowed (WD) decoding scheme for decoding the whole TB by exploiting the coupled information between CBs. Both decoding schemes achieve a considerable signal-to-noise-ratio (SNR) gain compared to the LTE Turbo codes. We construct the extrinsic information transfer (EXIT) functions for the LTE Turbo codes and our proposed IC Turbo codes from the EXIT functions of underlying convolutional codes. An SNR gain upper bound of our proposed codes over the LTE Turbo codes is derived and calculated by the constructed EXIT charts. Numerical results show that the proposed codes achieve an SNR gain of 0.25 dB to 0.72 dB for various code parameters at a TB error rate level of $10^{-2}$, which complies with the derived SNR gain upper bound.Comment: 13 pages, 12 figure

The Influence of Assembly Unit of Fibers on the Mechanical and Long-Term Properties of Reactive Powder Concrete

The corrosion of concrete structures by chloride salt is very significant in coastal environments. In order to improve the durability of marine concrete structures, cement-based materials with high durability need to be developed. In this investigation, the influence of NaCl freeze–thaw cycles (FT-C) and NaCl dry-wet alternations (DW-A) on the flexural and compressive strengths of reactive powder concrete (RPC) with an assembly unit of basalt fibers and steel fibers is studied. Additionally, the mass loss rate, the relative dynamic modulus of elasticity (RDEM), the chloride ion migration coefficient (CMC) and the impact toughness are measured after the NaCl FT-C and DW-A action. Our findings show that the RDEM, mass loss, and mechanical strength loss of RPC are increased by the ascending NaCl FT-C and DW-A. Meanwhile, the RDEM and the impact toughness are decreased by the NaCl FT-C and DW-A. The RPC with 0.5% basalt fibers and 1.5% steel fibers by volume of RPC shows the optimum mechanical performance and resistance to NaCl FT-C and DW-A. However, RPC with 3% steel fibers shows the worst resistance to NaCl erosion. The maximum mass loss rates, RDEM, flexural strength loss rate, compressive strength loss rate, CMC and impact toughness of all specimens after 300 NaCl FT-C and 30 NaCl DW-A are 4.5%, 91.7%, 28.1%, 29.3%, 3.2 × 10−12 (m2/s) and 2471 J. Meanwhile, the corresponding minimum values are 1.62%, 83.2%, 20.4%, 15.7%, 1.1 × 10−12 (m2/s) and 625 J. The researching findings will provide an optimum mix ratio of RPC with an assembly unit of basalt fibers and steel fibers, which can be applied in the marine engineering environment