Applied Mechanics and Materials Vols. 631-632

Abstract: In order to achieve the query of the topology for optical fiber, transform the original problem into a node traverse problem on the graph by treating the optical fiber cable resources management system as graph model. Through the analysis of the physical structure of the optical cable and related business, reinvesting the nodes and edges on the graph with different meaning.Setting up some special edge to reduce the search for node,and the traditional traversal algorithm is improved by this strategy.At last the result of experiment for this algorithm design is shown on Google-Map.

Abstract: TD-LTE technology can be introduced to improve the performance of military wireless communication system greatly for its better capability of broadband transmission while existing military wireless communication network cannot meet with the increase and further requirements of military task types. The technical characteristics and advantages of TD-LTE are analyzed, the problem of security, anti-jamming and mobility which are to be solved if TD-LTE technology applied in military are mainly studied, and the technical solutions are given.

Abstract: In the letter, a system of continuous phase modulation (CPM) with threaded space time codes (TSTC) is proposed for multiple-input multiple-output systems. In the system, source bits are coded via outer coder of Reed Solomon (RS). The codeword of which is suitable for TSTC design. Then inner coder mainly converts binary symbols into M-ary symbols for purpose of CPM. At receiver, Joint soft decoding approach is considered. Finally simulation results are provided for VBLAST, DBLAST, and TSTC as comparison.

Abstract: OFDM (Orthogonal Frequency Division Multiplexing) is a special kind of multi-carrier digital modulation technique. Each OFDM subcarrier exists orthogonality and great use of spectrum resources. To a certain extent, the problem of shortage of spectrum resources will be eased in the future. OFDM has a good ability to resist inter symbol interference and fight against frequency selective fading, and be able to adapt to the future wireless high-speed data transmission without distortion. Each channel modulation and demodulation with FFT and IFFT is easy to implement and meet the need of the business in the wireless communication system. The paper introduces the basic principle of OFDM technology, describes the advantages of OFDM and the defects needed to be overcome. Moreover, we analyzes the characteristics of 4G technology and discusses the application of OFDM in 4G mobile network.

Abstract: Enslaved by atmospheric turbulence and transmission power, performance of Free-space Optical Communication (FSO) fluctuates greatly. A new communication system of MIMO-CPolSK combined the MIMO system and CPolSK modulation is proposed in this paper. According to the strength of turbulence, different mathematical models of atmospheric channel are adopted. The BER calculating formula of SISO-CPolSK is proposed at first, then the BER performance of MISO-CPolSK and MIMO-CPolSK system is presented. The result of numerical simulation shows that BER performance is greatly promoted in MIMO system and compared to OOK modulation, the SNR of receiving in CPolSK modulation is reduced about 3dB when the system has the same BER performance under the same condition.

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) has gained great attention in the next generation Long-Reach Passive Optical Network (LR-PON) due to its high spectrum efficiency, flexible resource allocation and natural compatibility with Digital Signal Processing (DSP)-based implementation. In this paper, we propose and demonstrate a 40Gbit/s direct-detection long reach OFDM-PON system for downstream transmission over 100km standard signal mode fiber (SSMF). By using a simple Least Square (LS) method for the channel estimation, our proposed system achieves high bit rate without the need for chromatic dispersion compensation.

Abstract: Medium voltage broadband power line communication is the key component of distribution automation communication. In this paper, medium voltage broadband buried cable communication system was studied. The buried cable communication channel model was established; Reference to the IEEE P1901 standard requirements, the broadband power line communication system based on OFDM was simulated; the transmission rate was tested with the experimental system. The simulation results and actual tests show that the broadband buried cable communication system has good performance and high transmission rate which can meet the requirements of distribution network automation.

Abstract: Based on available data and predictions of power distribution and utilization communication services in smart grid of a realistic province, a plan for power communication network is proposed. For access network, communication strategies are explored based on load density of different power supply areas. As for transport network, architecture of trunk and local network is designed and its feasibility is discussed in terms of bandwidth utilization and network survivability.

Abstract: Spectrum sensing is a new technology in cognitive radio network, whose main purpose is to design an optimal detector. This paper studies a soft linear cooperative spectrum sensing method. We propose a SNR-based algorithm for weight setting at fusion center to improve the detector performance. Simulation results shows that the SNR-based method has better detector performance than the others.

Abstract: Virtual Power Plant (VPP) is recognized as essential for the successful implementation of smart grids, and information communication technology is enabling technology for VPP implementation. However, finding the most appropriate technology that can satisfy their future communication needs is still an unsolving issue for VPP. Focusing on the hierarchial VPP control model, and utilizing Ethernet Passive Optical Network (EPON) network technology, this paper has presented an EPON-based communication architecture for virtual power plant.