Energy efficiency of error control coding in intra-chip RF/wireless interconnect systems

Continuous scaling of conventional hard-wired metal interconnects into deep sub-micrometer region (DSM) has resulted in significant performance degradation in terms of delay, crosstalk noise, higher power dissipation, and decreased tolerance to noise. Besides, communication-centric nature of system-on-chip (SOC) networks requires efficient intra- and inter-chip interconnect technologies. Radio-frequency (RF)/wireless interconnects promise to be the best alternative to metal interconnects as they are compatible with current CMOS-technology, and they also provide higher data rate and bi-directional multi I/O transmissions. This paper evaluates the system bit-error-rate (BER) performance with the application of fault-tolerance capability using linear error-control codes (ECCs) within chip (intra-chip) RF/wireless interconnect systems. It also evaluates the utility of ECCs by considering energy consumed in ECC encoding-decoding vis-à-vis the energy saved due to coding gain by calculating the critical distance (d_cr). The results indicate that for a certain range of received signal-to-noise ratio (SNR), application of ECC improves the BER performance of the RF/wireless interconnect system. It is also shown that d_cr drops to 0.7 mm at 18 GHz.     

Application-aware virtual paths insertion for NOCs

Network-on-chip (NoC) has rapidly become a promising alternative for complex system-on-chip architectures including recent multicore architectures. Additionally, optimizing NoC architectures with respect to different design objectives that are suitable for a particular application domain is crucial for achieving high-performance and energy-efficient customized solutions. Despite the fact that many researches have provided various solutions for different aspects of NoCs design, a comprehensive NoCs system solution has not emerged yet. This paper presents a novel methodology to provide a solution for complex on-chip communication problems to reduce power, latency and area overhead. Our proposed NoC communication architecture is based on setting up virtual source–destination paths between selected pairs of NoCs cores so that the packets belonging to distance nodes in the network can bypass intermediate routers while traveling through these virtual paths. In this scheme, the paths are constructed for an application based on its task-graph at the design time. After that, the run time scheduling mechanism is applied to improve the buffer management, virtual channel and switch allocation schemes and hence, the constructed paths are optimized dynamically. Moreover, in our design the router complexity and its overheads are reduced. Additionally, the suggested router has been implemented on Xilinx Virtex-5 FPGA family. The evaluation results captured by SPLASH-2 benchmark suite reveal that in comparison with the conventional NoC router, the proposed router takes 25% and 53% reduction in latency and energy, respectively besides 3.5% area overhead. Indeed, our experimental results demonstrate a significant reduction in the average packet latency and total power consumption with negligible area overhead.     

基于树状图的电力光纤通信网安全风险模型

文章提出了基于树状图的电力光纤通信网安全风险的量化模型,详细分析了风险与其各个要素资产、威胁、脆弱性和安全措施之间的关系,并用公式具体解释了它们是如何构成风险的,结合电力通信网对各个因素的概念分类进行了阐述.通过建立树状图模型,得出各个因素之间的对应关系,对其合理赋值,通过计算得出了风险值,最后通过实例对模型进行了验证.     

临近空间激光通信信道特性及系统分析

临近空间飞行技术的发展使临近空间激光通信的实现成为了可能。由于临近空间飞行器的飞行特点独特,故信道特性的不同成为临近空间激光通信与一般空间激光通信之间的重要差异之处,因此信道分析是临近空间激光通信的理论研究中的关键内容之一。在分析临近空间激光信道的特殊性的基础上,应用信道衰减和湍流模型,探讨斜程信道随天顶角的变化规律。同时应用光束数值仿真方法模拟临近空间激光信道及通信系统性能,讨论了天顶角变化时衰减和湍流对通信质量的影响,提出对临近空间激光通信系统的可能的重要影响因素。     

高速光通信的前向纠错技术研究

根据高速光通信系统对于OSNR(光信噪比)的要求,提出了一种基于非规则LDPC(低密度单奇偶校验)长码的Super-FEC(超级前向纠错)方案。Super-FEC方案采用以不同进制的BCH(博斯-查德胡里-霍昆格姆)码为外码,LDPC码为内码的级联方式。针对系统不同的码率需求,分别设计了不同的级联构造形式。仿真结果表明,这些Super-FEC方案的净编码增益为6.18～7.63dB,高于传统方案。     

A novel modulation for mobile satellite communications

It is a challenging problem to design a high performance modulation for mobile satellite communications due to the limited power and bandwidth resource. The paper improves Feher patented Quadrature Phase Shift Keying (FQPSK) by redefining the waveform. The novel FQPSK, with constant envelope, can be used to improve the power efficiency and frequency efficiency of mobile satellite communication. The study shows that the improved FQPSK outperforms conventional FQPSK over AWGN and is immune to the non-linearity of high power amplifier. At last, the impact of flat fading and multi-path fading of channel on the BER performance of improved modulation is analyzed.     

卫星通信中的高阶调制技术研究

总结了卫星通信协议GMR-1、DVB中的高阶调制技术,研究了16QAM、16APSK、32APSK调制原理,分析了卫星信道模型,利用Matlab分别搭建AWGN信道和Rician-K信道下各高阶调制信号的收发,得到不同的调制方式在不同信道或在不同衰落因子同一信道下的误码性能。本文的仿真结果对实际卫星通信系统采用高阶调制技术有着一定的借鉴意义。     

分集激光通信高速率半导体激光器驱动设计

为了实现高速率大气分集激光通信,研究并设计一种适用于高速率激光通信用驱动系统,对半导体激光器调制基本特性、频率稳定度和驱动阈值变化等特性进行了分析,通过实验验证了设计的性能。实验结果表明,系统在发射功率-3dBm,误码率小于10-6的情况下,半导体激光器频率长效稳定,驱动速率达到2.5Gb/s,基本满足大气激光通信的稳定度可靠、高速率和抗干扰等方面的要求。     

Differential M-ary orthogonal signaling for DS/CDMA land mobilesatellite communications

In this paper, we derive an analytical framework for the performance evaluation of an M-ary orthogonal scheme based on differential encoding/decoding of the Walsh/Hadamard chips prior/after spreading. This technique makes feasible nonpilot-assisted detection over fast fading environments such as the land mobile satellite (LMS) channel. Our results show that differential M-ary orthogonal signaling presents very good performance at Doppler frequency shifts much higher than the symbol rate. Amplitude statistics are considered to be Rayleigh, but may be easily extended to more general models based on the analytical derivation presented     

一种新型互联电网解列切负荷装置的微机实现

解列和切负荷是维持电网稳定，防止“电压崩滞”和“频率崩溃”的重要措施，应用AT89C52单片机及外围设备构成互联网解列装置，可对电网参数实时在线监视，根据电网稳定计算的结论，实施解列或切负荷，恢复电网稳定。     

Evaluation of light beams for short and medium range wireless communications

Technological improvements in free space optical communication systems have reduced the cost and alternatives to fiber optic transmission. The advantages of the free space optical link over fiber optic cabling are primarily economic. In line with the demand for gigabyte link from 10 Mbit/s to 10 Gbit/s in the market, the uses of free space optical communication systems have increased exponentially from 1995 to 2008. However, free space optics is subject to atmospheric effects such as attenuation and scintillation which can reduce link availability and may introduce errors not seen in fiber transmission. In this paper we argue that optical wireless communication is an alternative to fiber optic transmission in short and medium range wireless communications and we discuss that the liability and availability of the free space optical link is mainly determined by the local atmospheric condition, this is to say that the transmission quality may be affected by weather conditions. For the evaluation we constructed an experimental communication network with a free space system. One way to characterize the strength of the turbulence fluctuation is by examining the Rytov variance for a plane wave. This Rytov variance physically represents the intensity fluctuation induced by atmospheric turbulence.     

车载电子通信安全技术研究

在汽车功能多样化、集中化迅速发展的今天,对车载电子通讯安全技术的要求越来越高,从而不断加强对车载电子通信安全技术的相关研究。因为车载电子通信系统涉及汽车技术、计算机技术、电子技术、无线通信技术等多种应用系统,所以其安全问题极为复杂,对车载电子通信安全技术的要求也越来越高。     

一种结构新颖的压控环形振荡器

提出了一种新颖的压控环形振荡器的电路实现结构,着重分析了该压控振荡器的线性度。该电路全部由ＭＯＳ管实现,因而易于集成在先进的片上系统中。该线性环 振荡器是片上天线无线通讯测试系统的一个部分,用特许半导体公司的０．６μｍＣＭＯＳ数字工艺实现。     

CMOS design and analysis of low-voltage signaling methodology for energy efficient on-chip interconnects

This paper provides a comparative study of the low-voltage signaling methodologies in terms of delay, energy dissipation, and energy delay product (energy×delay), and sensitivity technology process variations, and noise. We also present the design of two symmetric low-swing driver-receiver pairs for driving signals on the global interconnect lines. The key advantage of the proposed signaling schemes is that they require only one power supply and threshold voltage, hence significantly reducing the design complexity. The proposed signaling schemes were implemented on 1.0 V CMOS technology, for signal transmission along a wire-length of 10 mm. When compared with other counterpart symmetric and asymmetric low-swing signaling schemes, the proposed schemes perform better in terms of delay, energy dissipation and energy×delay.     

VLSI设计规划中互连串扰的峰值估计

提出了一组新的基于RLC模型的VLSI互连串扰峰值估计公式.根据高速VLSI互连特性建立了混πRLC模型,推导出分量匹配法3阶系数的精确表达式,得到了只与R、L、C分布参数有关的互连线串扰峰值估计公式.计算实验表明,该公式与SPICE仿真结果符合得较好.将该估计公式嵌入各种综合引擎和工具,能够在高速、高密度、大规模集成电路的设计阶段预测信号性能.     

基于消息认证码的安全有效的组播源认证

组播通信正成为不断增长的应用基础，而其关键是要为组通信提供可靠的安全机制，然而，现有的组播安全协议仅能提供部分的解决方法，考虑到源认证是组的最主要安全事务之一，文章基于消息认证码提出了一种安全有效的组播源认证方法。     

Evaluating the effects of temperature gradients and currents nonuniformity in on-chip interconnects

The paper provides a compact but accurate electro-thermal model of a long wiring on-chip interconnect embedded in the complex layout of a ULSI digital circuit. The proposed technique takes into account both the effect of temperature gradients over the chip substrate and the interconnect self-heating due to current flow. The proposed compact model is well suited to be interfaced with commercially available CAD tools employed for interconnect parasitic extraction and signal integrity verification. The paper also investigates the electro-thermal effects that arise in a long wiring on-chip interconnect in which current flow is dominated by displacement currents and thus is not uniform along the line.     

光纤局域网应用的有源器件和无源器件

从光纤局域网应用的观点,评述对光学有源器件和无源器件的要求及进展,并展望这些器件未来的发展趋势。     

基于无线通信的智能婴儿监控系统的设计与实现

应用无线通信技术的智能婴儿监控系统减少了系统各部分间的电缆连接。介绍了以计算机技术为核心,以89C51系列单片机、DS18B20温度传感器、HS1100/HS1101湿度传感器和HK-2000A集成化脉搏传感器等组成的智能婴儿监控系统,实现对婴儿体征的采集,以及能环境信息的采集,通过NewMsg-RF2401无线传输模块将信息传输到终端,实现婴儿信息实时监控的目的。