Advanced Materials Research Vols. 546-547

Abstract: The key issue of wireless sensor networks is to balance the energy costs of the entire network, to enhance the robustness of the entire sensor network. Sensor networks as a special kind of complex network, in particular, environmental constraints, and more from the traditional complex networks, such as Internet networks, ecological networks, social networks, is to introduce a way of wireless sensor networks way of complex networks theory and analytical method, the key lies in, which is a successful model of complex network theory and analysis methods, more suitable for the application of wireless sensor networks, in order to achieve certain characteristics of some wireless sensor networks to optimize the network. Considering multi-hop transmission of sensor network, this paper has proposed a maximum restriction on the communication radius of each sensor node; in order to improve the efficiency of energy consumption and maintain the sparsely of the entire network, this paper has also added a minimum restriction on the communication radius of each sensor node to the improved model; to balance the energy consumption of the entire network, The simulation results show that proposed improvements to the entire network more robust to random failure and energy costs are more balanced and reasonable. This is more applicable to wireless sensor networks.

Abstract: Data synchronization is critical for many sensor network operations including collaborative sensing, sensor scheduling and data fusion. Currently, large number of synchronization schemes have been proposed for the sensor network under the assumption that sensors work with the same network structure, network protocol and radio module. These techniques cannot survive in the heterogeneous sensor networks with the development of internet of things. In this paper, we propose a lightweight data synchronization scheme with low power which consists of two phases: first, we propose a heterogeneous clock synchronization algorithm based on the gateway which can synchronize the multi-hop sensor network with the TCP/IP network immediately without introducing amount of communication overhead; then, we also propose a synchronization control scheme in the gateway and we can balance the synchronization requirements through the adaptive buffer management. We implement the proposed scheme in real heterogeneous sensor network platform, and the experiment results show that our scheme can achieve high synchronization accuracy.

Abstract: In this paper, a comparison by several kinds of video surveillance technology, highlights the superiority of video monitoring system based on the embedded system. Video monitoring system is a collection of computer technology, the communication technology and digital video technology in an integrated system. Established a video monitoring system based on embedded technology, detailed analysis its system structure and gives its hardware and software design.

Abstract: A simulation test methodology has been developed to evaluate Satellite-Network Routing Algorithms. The test technique simulates problems routing algorithms encounter in satellite network by selecting the routing strategies which take minimal hop, minimal delay, and minimal transmitting power as principles and addressing them from building a satellite network simulation scenario in which the simulation test approach is applied and recording their performances in the form of statistical summaries.

Abstract: In satellite communications, it is often necessary to broadcast large data to terrestrial users. Because the satellite channel is a typical fading channel, packets can’t be correctly received. Therefore, retransmission is necessary. This paper proposes a network-coding-based broadcasting retransmission approach, whose key idea is to combine different lost packets with network coding to achieve minimum number of retransmission. Simulation results indicate that compared with existing approaches, network-coding-based broadcasting retransmission approach can effectively reduce average number of transmissions.

Abstract: In this paper, we focus on the need for remote and robust underwater acoustic(UWA) communication in shallow sea. A set of OFDM underwater acoustic communication algorithm is designed including the techniques of Doppler estimation and compensation, channel equalization and frequency diversity. This algorithm is realized in the DSP and successfully applied on the OFDM-Modem platform. In Da- Lian shallow sea trial, the horizontal communication distance is 36 kilometers under the condition of QPSK modulation, 1/2 rate convolution code, bandwidth between 4 and 8kHz. The communication rate of the OFDM-Modem can reach 426bps and the ultimate BER is less than 10-3.

Abstract: Integration of the wireless LANs (WLAN) and 3G networks, such as Universal Mobile Telecommunication Service (UMTS), has been intensively studied recently due to their complementary characteristics. In this paper, we design and implement a flexible protocol stack architecture which can support concurrent transmission via multiple radio interfaces. Furthermore, the multiple services with various QoS requirements are differentiated and transported in the best wireless access network which is determined by the proposed network selection criterion-- Multi-Criteria Decision Making (MCDM), in the heterogeneous wireless network. Simulation results demonstrate that the proposed concurrent transmission scheme improves the network utility and provide the QoS services among the multiple wireless access networks more efficiently.

Abstract: This paper describes the software of the track state inspection system based on LABVIEW, which includes serial communication, data extraction, strap-down algorithm, acceleration integral and saving the results. Serial communication module uses VISA to program in order to realize communication between the IMU (inertial measurement unit)and upper computer. According to the output data format, data extraction module separates the signal of three axes’ accelerations and angular-rates by Match Pattern Function. Strap-down algorithm and acceleration integral modules are programmed by Math Script. The measurement results are saved by Write to Spreadsheet File Function. Finally, it’s to design a convenient humanized operation interface.

Abstract: PAR (Peak-to-Average Power Ratio) is one of significant issues in a DRM transmitter. To reduce the PAR of DRM signals, an iterative pre-distortion technique is proposed in this paper. This technique improves the RMS (Root Mean Square) power of transmitter while the effect on DRM signal quality is negligible. Research has been done on the impact that the processing parameters caused to DRM signal quality. Simulation and test indicate that in the case that the quality requirements for the RF signal in the DRM specification is satisfied, DRM output power is increased to 9kw from 5kw (RMS power) based on a 10kw (carrier power) DX transmitter, thereby improving the capability of the transmitter greatly.

Abstract: Wireless sensor network is a new type of wireless network. IEEE 802.15.4 / Zigbee standards with low energy consumption, low speed characteristics has been widely used in wireless sensor network. As the wireless sensor nodes are often set in complex geographical environment and had not continuous power supply, thus saving energy has been one of the main directions of research at home and abroad. Cellular automata are a mimic biological cell reproduction form of dynamical system, with a simple rule to reveal the complex global characteristics. This paper presents a kind of cellular automata and Zigbee based wireless sensor network binding mechanism, so that the wireless node according to the communication state during hibernation and job switching between states in order to achieve the purpose of energy saving. Simulations show that the mechanism can reduce the network energy consumption, improve energy utilization rate, and prolong the survival time of the node.