Applied Mechanics and Materials Vols. 347-350

Abstract: For the purpose of convenient control in the process of realising Vitual Maintenance System based on EEVMP(Electronic Equipment Virtual Maintenance Prototyping), make an research on real-time moving method of mouse controling three-dimensional model. It analyzedes the process of coordinate transform.And then,explains the figure course of real-time model move. It realises the real-time model moving in a electronic equipment virtual maintence system in the end.

Abstract: A submicron InGaAs/InP DHBT fabricated using triple mesa structure and BCB planarization technology is presented. All processes are on 3-inch wafers. The DHBT with emitter area of 0.7×10μm2 exhibits a current cutoff frequency ft and a maximum oscillation frequency fmax both of 280GHz. The breakdown voltage is more than 4V. The high speed InGaAs/InP DHBT with comparable high breakdown voltage is promising for voltage controlled oscillator (VCO) and mixer applications at W band or even higher frequencies.

Abstract: In this paper,we design a uniform circular array beamforming device of 16 yuan based on the least squares SLC-LSCMA algorithm (based on the linear subspace constrained least squares cma) high stability and rapid convergence for the foundation. The design of the complete beam-forming the SLC-LSCMA algorithm by plural, time-multiplier and accumulators, which uses less resources and faster than the traditional algorithm. The beamforming device uses hardware description language of Verilog HDL , and wires on the QUARTUS II 8.0. Finally the beamforming device is downloaded to the Alteras EP2C35F672C6, and its timing simulation can be run properly in the 50MHz clock frequency. This design can be widely used in mobile communication and satellite communications.

Abstract: SC-FDMA as LTE uplink main technology has been widely studied,at the same time, channel estimation around such technology is becoming hot,In order to research and increase channel estimation accuracy of LTE uplink system,an algorithm based on pilot is proposed in this paper,this algorithms main idea is,by setting a certain bit error rate,choosing some proper data after channel estimation done under R-LS and M-MMSE, combining the chosen data and former block pilot and increasing pilot number to do channel estimation again, system bit error rate and mean square error results can be got by simulation;at last,the theoretical analysis and simulation results show that this algorithm really can make the channel estimation accuracy improved and bit error rate decreased.

Abstract: A thorough OFDM parameter design method of a digital broadcasting system in FM band is presented in this paper. Key OFDM parameters are analyzed from their constraints. Cyclic prefix should satisfy the requirement of channel delay and formation of SFN. Design of system bandwidth should consider coherent bandwidth and existing frequency planning. Symbol duration is restricted by time selectivity and frequency selectivity of the channel, and also efficient SINR should be maximized. System simulation is performed to test and verify the parameters under typical FM band channels. A set of OFDM parameter is provided for future design.

Abstract: A compact and simple ultra-wideband microstrip-fed planar antenna with double bandstop characteristic is presented. The antenna consists of a rectangular monopole and two W-shaped slots inserted into the radiating patch and the truncated ground plane. By using a W-shaped slot defected ground structure (DGS) in the feedline, a stopband of 800 MHz (from 5.1 to 5.9 GHz) for band rejection of wireless local area network (WLAN) is achieved. To obtain the other stopband (from 3.7-4.4 GHz), a same shaped slot is etched into the monopole. Moreover, the two stopbands can be controlled by adjusting the length of the slot respectively. The simulation results show that the designed antenna, with a compact size of 38.5 mm×42.5 mm, has an impedance bandwidth of 2.811 GHz for voltage standing wave ratio (VSWR) less than 2, besides two frequency stopbands of 3.74.4 GHz and 5.15.9 GHz. Moreover, the main features including omnidirectional H-plane radiation patterns and the appropriate impedance characteristic are achieved by beveling the radiating patch and the microstrip-fed line of the proposed antenna.

Abstract: In directed diffusion rooting protocol, interest and exploratory data are disseminated by flooding, which will bring broadcast storm resulting in substantial energy consumption of wireless sensor networks. Grid-based directed diffusion rooting protocol can improve energy efficiency where geographic grids are constructed by self-organization of nodes using location information. Flooding of interest and exploratory data is limited in grid head nodes. But grid-based directed diffusion rooting protocol considers less about security. To adapt to environments with high security requirements, traffic attack detection and secure data aggregation schemes are added to grid-based directed diffusion rooting protocol. Simulation shows that the proposed schemes can real-time predict traffic attacks and improve accuracy of data aggregation results when networks are under attacks. At the same time, the protocol consumes less energy and extends lifetime of networks.

Abstract: In according to the issue of multi-signal jamming in communication reconnaissance, single channel signal separation for multi-GMSK signals has been studied with a method based on MLP. With parameters of Doppler-shift, time-delay, amplitude and coding sequences efficiently estimated, signals could be restructured, and then be separated. Simulations have proved well separation results can be obtained with the method for unequal power signals with certain SNRs.

Abstract: This paper uses an industrial control product as a teaching platform, the necessary foundation of theoretical teaching and practical exercises which is combined, so that students quickly grasp the embedded industrial control system software and hardware, the basics of the system hardware and software analysis, circuit testing, and has strong ability to application. It can improve students on the practical aspects of the initiative and enthusiasm by courses. Improve the requirements of the course on the basis of the original experiment, the validation and repeated cross-experiment is deleted, which is contributed to save hours and improve efficiency. Due to the application of advanced processing technology, so it can reduce the distance of the school teaching and social applications.

Abstract: Frequency spectrum scarcity is currently one of the mostly discussed topics in wireless communications. When there is no free spectrum available, no new broadband communication techniques can be put into operation. The double use of already assigned frequencies leads to interferences. A possible solution to the problem is Dynamic Spectrum Access (DSA), realized through Cognitive Radio (CR) technology. Cognitive Radios have the ability to detect unused spectrum segments and to adapt to it dynamically. This adaptation does not only concern a change of frequency, but may also include changes in waveform, bandwidth, or whatever leads to an optimal communication link. This paper gives an overview of the state-of-the-art Cognitive Radio approaches and points out opportunities offered by this technology to overcome the threat of spectrum scarcity.