An integrated FEC coding scheme for ATM transmission over regenerative satellite networks

The application of asynchronous transfer mode (ATM) on both wireless and satellite networks requires system adaptation. This adaptation has to improve the overall system's performance, and achieve high quality‐of‐service classes approaching that for fibre‐optic communications. In this paper, a new integrated forward‐error‐correction (FEC) coding scheme is introduced for ATM transmission over regenerative satellite networks. The proposed FEC scheme is a concatenation of two Reed–Solomon codes tailored for the header and payload parts of the ATM cell. This integrated coding scheme is shown to significantly improve the cell loss ratio as compared to the standard CRC code used in the ATM cell header. We obtain both upper and lower performance bounds for the concatenated code and check their accuracy when compared to exact system's performance. Both analytical and simulation results show that a cell loss ratio and bit‐error rate (BER) of 10^?25 and 10^?7 can be, respectively, achieved with minimum delay requirements on the SATCOM link. Finally, an approximation for the system's throughout is obtained. It is shown that using a hybrid selective‐repeat automatic‐repeat‐request (SR‐ARQ) with the RS code, a large throughput of approximately 0.843 can be achieved at BERs lower than 10^?7 for data services. Copyright © 2005 John Wiley & Sons, Ltd.     

弱对偶基下比特并行RS编码器的设计

讨论了高速RS码编码器的设计问题。研究了有限域元素在弱对偶基（WDB）下的表示,基于弱对偶基下的最优弱对偶基的计算方法,给出了有限域比特并行乘法器的设计过程,并且利用这样的乘法器构成了广泛应用的RS（255,223）码的编码器。RS（255,223）码的编码器的复杂度定量的分析结果表明：弱对偶基下的比特并行乘法器设计复杂度降低,便于VLSI实现。编码器的数据吞吐率可达较高值,有利于高速应用场合。     

低时延RS-CC级联码的设计与实现

为提高手持无线电台的纠错和时延特性,考虑设计一种短码长RS-CC级联码.通过对Reed-Solomon码缩短和截断以及对卷积码删余,提出了一种低时延的级联码设计方案,并进行性能分析和软硬件实现.结果表明,在高斯信道下,当Eb/No达到4.2 dB时,能够实现10-4的误码率性能.设计的RS-CC级联码码长较短,编解码固有时延低,译码速度提升30％,适合低时延应用.     

Hyperelliptic curves encryption combined with block codes for Gaussian channel

In this paper, a new cryptographic system is constructed using a combination of a hyperelliptic curve of genus g = 2 over the Galois field GF(2ⁿ) and a Reed–Solomon code (N, K) over the Galois field GF(2^m) and this system uses a smaller key than the elliptic curves cryptosystem and the Rivest, Shamir, and Adleman cryptosystem. The design criterion for the combination can be expressed as the data compression condition and addressing capability of the code. In addition, the system performance is compared with other systems; extraordinary improvements of 8 and 16.5 dB can be obtained for a BER = 10^?5, when compared with binary phase shift keying and differential chaos shift keying, respectively. This system has a polynomial complexity, which depends on data length and the number of operations in GF(2ⁿ). Copyright © 2005 John Wiley & Sons, Ltd.     

改进型蚁群算法参数优化研究

研究在不使用局部搜索情况下参数组合对改进型蚁群算法的影响。以带时间窗的车辆路径问题为例,针对基于最大最小蚁群算法的改进蚁群算法中的五个参数,运用均匀设计法对最优参数配置问题进行了研究。仿真实验表明改进的蚁群算法效果明显,能有效解决Solomon数据集中的R类和RC类问题,且具有较强的鲁棒性。对最优参数的局部调整没有明显提高算法获取最优解能力的问题,分析了其可能的原因。     

An algorithm for the selection of effective error correction coding in wireless networks based on a lookup table structure

In this paper, we propose an adaptive Forward Error Correction (FEC) coding algorithm at the Medium Access Control (MAC) layer used in wireless networks. Our algorithm is based on the lookup table architecture, including a distance lookup table and a bit error rate lookup table. These tables will store the best value of the FEC codes based on different distances and bit error rates. Because radio channels change over time, the bit error rate is always changing, or in the case of mobile nodes, when the transmission distance changes, the bit error rate also changes, so previously proposed algorithms take longer to find the optimal value of the FEC code for data transmission. Our proposed algorithm, however, is based on 2 lookup tables, and thus, it can always quickly select an optimal FEC code during early data transmissions and achieve high performance. We compare our algorithm with other methods based on performance metrics such as the recovery overhead of FEC codes, energy efficiency, and peak‐signal‐to‐noise ratio values in the case of image transmission. Our simulation indicates that the proposed algorithm achieves better performances and proves the correctness of the proposed lookup table architecture.     

An Enthusiastic Sceptic

Nat Oppenheimer , principal of structural engineers Robert Silman Associates, is a dissenting voice among the advocates of building information modelling (BIM) - an enthusiastic sceptic. Could the quest for integration be leading towards oversimplification rather than customisation and differentiation? Even towards the sort of standardisation adopted with LEED ratings in the quest for sustainability? Copyright © 2009 John Wiley & Sons, Ltd.     

Reduction of PAPR in coded OFDM using fast Reed-Solomon codes over prime Galois fields

In this work, two new techniques using Reed–Solomon (RS) codes over GF(257) and GF(65,537) are proposed for peak-to-average power ratio (PAPR) reduction in coded orthogonal frequency division multiplexing (OFDM) systems. The lengths of these codes are well-matched to the length of OFDM frames. Over these fields, the block lengths of codes are powers of two and we fully exploit the radix-2 fast Fourier transform algorithms. Multiplications and additions are simple modulus operations. These codes provide desirable randomness with a small perturbation in information symbols that is essential for generation of different statistically independent candidates. Our simulations show that the PAPR reduction ability of RS codes is the same as that of conventional selected mapping (SLM), but contrary to SLM, we can get error correction capability. Also for the second proposed technique, the transmission of side information is not needed. To the best of our knowledge, this is the first work using RS codes for PAPR reduction in single-input single-output systems.     

Gibraltar: A Reed‐Solomon coding library for storage applications on programmable graphics processors

Reed–Solomon coding is a method for generating arbitrary amounts of erasure correction information from original data via matrix–vector multiplication in finite fields. Previous work has shown that modern CPUs are not well‐matched to this type of computation, requiring applications that depend on Reed–Solomon coding at high speeds (such as high‐performance storage arrays) to use hardware implementations. This work demonstrates that high performance is possible with current cost‐effective graphics processing units across a wide range of operating conditions and describes how performance will likely evolve in similar architectures. It describes the characteristics of the graphics processing unit architecture that enable high‐speed Reed–Solomon coding. A high‐performance practical library, Gibraltar, has been prototyped that performs Reed–Solomon coding on graphics processors in a manner suitable for storage arrays, along with applications with similar data resiliency needs. This library enables variably resilient erasure correcting codes to be used in a broad range of applications. Its performance is compared with that of a widely available CPU implementation, and a rationale for its API is presented. Its practicality is demonstrated through a usage example. Copyright © 2011 John Wiley & Sons, Ltd.     

基于Intel ISA-L的RS-RAID系统的研究与实现

由于传统RAID技术自身的局限性,导致其难以在更高的可靠性、I/O性能以及存储空间利用率之间取得良好的平衡。RS-RAID（Reed Solomon RAID）能够提供更高的可靠性,并且具有较高的存储空间利用率,但仍存在I/O性能低和数据恢复时间长的重要问题。基于Intel ISA-L的RS-RAID通过使用Intel ISA-L库加速RS码的计算速度,提高了RS-RAID的I/O性能;通过使用有效数据bitmap记录磁盘中实际需要恢复的数据,减少了RS-RAID在数据恢复过程中需要恢复的数据量,从而降低了RS-RAID的数据恢复时间。