Measures for Error Avalanche and Energy Avalanche Effect in Secure Wireless Fieldbus Systems

The wireless fieldbus is a vital part in present industrial automatic controls and software-defined systems. Accompanying, security is an upcoming problem determines its future leapfrog development. Wireless fieldbus systems can be made secure by encrypting the data. Unfortunately, the diffusion character of encryption brings significant vulnerabilities in terms of deteriorated error performance and energy efficiency. In this paper, we first propose an AES-dependent Hsiao(AD-Hsiao) code to improve the error correction capability, which leverages the prior information of data similarity and AES decryption to assist syndrome decoding. Then, we develop "Random Coset" scheme to reduce energy consumption. Based on mapping written data into several data candidates, this scheme lessens the number of bits written to memory and thereby boosts the write energy efficiency. Simulation results show that the AD-Hsiao code can correct majority of double errors in a single codeword with limited latency and area cost as the Hamming code. Moreover, the(72,64) AD-Hsiao code improves the reliability by 102 over the(72,64) Hamming code at 8 dB AWGN channel, and also exceeding the high cost(78,64) BCH code. In addition, the "Random Coset" improves energy efficiency by 6.6～14% than the current scheme while re-quires small ROM storage.

Comparison of Achievable Rates of OFDM and Single Carrier Communication Systems

This paper presents a theoretical comparison of a single carrier system and a multi-carrier system through an analysis of the achievable rate under frequency selective fading with channel state information at the receiver. A scheme was designed to compare the achievable rates of a single carrier system and an Or- thogonal Frequency Division Multiplexing （OFDM） system. A thorough theoretical analysis of the two-path channel was conducted, and simulations were also used to analyze practical stochastic channels. Analysis and simulation results show that the achievable rates of the two approaches are comparable when the channel is flat fading. However, when the channel is frequency selective fading, the single carrier system outperforms the OFDM system. The achievable rate of the OFDM system is about 10% lower than that of the single carrier system at higher SNRs.

Design and Efficient Hardware Implementation Schemes for Non-Quasi-Cyclic LDPC Codes

The design of a high-speed decoder using traditional partly parallel architecture for Non-Quasi-Cyclic（NQC） Low-Density Parity-Check（LDPC） codes is a challenging problem due to its high memory-block cost and low hardware utilization efficiency. In this paper, we present efficient hardware implementation schemes for NQCLDPC codes. First, we propose an implementation-oriented construction scheme for NQC-LDPC codes to avoid memory-access conflict in the partly parallel decoder. Then, we propose a Modified Overlapped Message-Passing（MOMP） algorithm for the hardware implementation of NQC-LDPC codes. This algorithm doubles the hardware utilization efficiency and supports a higher degree of parallelism than that used in the Overlapped Message Passing（OMP） technique proposed in previous works. We also present single-core and multi-core decoder architectures in the proposed MOMP algorithm to reduce memory cost and improve circuit efficiency. Moreover, we introduce a technique called the cycle bus to further reduce the number of block RAMs in multi-core decoders. Using numerical examples, we show that, for a rate-2/3, length-15360 NQC-LDPC code with 8.43-d B coding gain for Binary PhaseShift Keying（BPSK） in an Additive White Gaussian Noise（AWGN） channel, the decoder with the proposed scheme achieves a 23.8%–52.6% reduction in logic utilization per Mbps and a 29.0%–90.0% reduction in message-memory bits per Mbps.

Generalized sparse codes for non-Gaussian channels:Code design,algorithms,and applications

In this paper,generalized sparse(GS)codes are proposed to support reliable and efficient transmission over non-Gaussian channels.Specifically,by expanding the single-parity check(SPC)code constraints with powerful algebraic codes,GS codes generalize conventional sparse codes with enhanced error-correcting capability,as well as better code design flexibility by covering a wide range of block-lengths and coding rates with reduced encoding/decoding complexity.Moreover,by introducing a universal communication channel model,a general framework for performance analysis and code design of GS codes is formulated,by which the coding parameters can be optimized for different target channel conditions.Finally,example codes are constructed for several critical application scenarios with non-Gaussian channels.Numerical simulations are performed to demonstrate the superiority of the proposed GS coding scheme to traditional channel coding schemes.