Applied Mechanics and Materials Vols. 263-266

Abstract: Timing synchronization is very important in the multi-carrier acoustic communication system. With regard to the transmitted signal of the baseband OFDM in the acoustic communication system, which is in the complex environment over the acoustic channel gauss noisy and SαS impulse noisy interference,this paper proposes a joint time delay and Doppler frequency shift estimation algorithm based on the fractional lower order cyclic cross ambiguity function with multi-cycle frequency(FCCAF). This method combines the fractional lower order moment with the feature of cycle stationary, and can detect the signal characteristic of cyclo-stationarity under the SaS impulse noisy. The algorithm takes full advantage of the cycle frequency information of the signal, and can be equipped with the capacity of suppression interference. The simulation results show that the algorithm proposed in this paper can work very well in the presence of the impulse noise and interference, the superior to that algorithm based on the second order cycle fuzzy function, and is a robust joint estimation algorithm with time delay and Doppler shift.

Abstract: By the requirements of reliable wireless communication, a new composite code scheme is proposed for orthogonal spreading codes in order to improve synchronization and error performance, which is based on certain criteria to select the composite codes. Simulation shows that the correlation property of the screened composite codes and the bit error rate performance are better than that of other composite codes.

Abstract: Optical fiber Raman amplifier (OFRA) with wide and flat gain bandwidth has been widely applied in the fields of optical communication, sensing and measurement. However, the performance optimization is always one of the hot topics in the study of OFRA, because its output characteristics are hardly dependent to some key designing parameters. In this paper, to overcome the problems above, we adopt a spectrum analysis based method to study the output performance of an OFRA system with backward pumping. By simulating the operation of the OFRA system, its output characteristics are first showed easily, with the advantages of real time, low cost, and low complexity. Further, according to the numerical results obtained, the optimal parameters of an OFRA system are determinate, and the performance in terms of output power, signal noise ratio, and the level of gain flatness is improved and optimized obviously.

Abstract: With the communication industry becoming more and more competitive, the communication operators is paying more and more attentions on the network quality. The paper proposed the terminal signal quality analysis model based on the time and location which uses the technology of the terminal routing tracking and the signal data analysising.The model starting with the time and location,combines with the signal data of the station and the terminal,associates to related data of the other systems,come to the signal qality of the terminal during the move.

Abstract: In order to solve the communication efficiency and the load balancing of P2P network, a multi-link concurrent P2P communication model is proposed. It introduces concurrent communication mechanism, assigns proper communication task to all nodes according to the communication capability of nodes and the communication weight between nodes, implements the traffic load balancing and shortens communication time. The model has high concurrency, strong robustness, and effective load balancing, so it is suitable for multicast communication and network data mass transmit.

Abstract: Shortwave DFH system is a new type of communication system, and it is widely used in various fields because of its good anti-interference and anti-fading ability performance in anti-interference and anti-fading. A shortwave DFH communication receiver is designed based on Virtex4-sx35 series FPGA development board using Verilog HDL and VHDL language, and the function of this receiver is implemented and simulated. The result of simulating shows that the designed shortwave DFH receiver is effectively.

Abstract: The RapidIO architecture is an interconnect technology based on a high-performance and packet-switched interconnect technology. The paper uses the RapidIO Interconnect technology to design a fiber optic bus. The fiber optic bus provides a tightly coupled interconnect with Gigabit speed, which can improve the processing capability of the space distributed system, such as the weapons platform with high-speed and high-capacity multi-system.

Abstract: A novel multipoint-to-multipoint bandwidth allocation algorithm named MP2MP-DBA based on 60GHz millimeter-wave communication is proposed for home network. Simulation results show that the MP2MP-DBA achieves better throughput and delay than static bandwidth allocation algorithm.

Abstract: With the popularity of the IEEE 802.11 standards, many analytical delay studies for the Distributed Coordination Function (DCF) have been reported. In this paper, we analyze the additional idle durations that a tagged node needs to wait due to other nodes transmissions. Separating the distributed inter-frame space (DIFS) and extended inter-frame space (EIFS) durations from the full time of a successful transmission, we provide a correct function analysis of the DIFS and EIFS durations and build a more accurate delay model for the IEEE 802.11 DCF. The theoretical analysis and simulation results prove that the proposed delay model is coincident with the real performance when the node number increases.

Abstract: To solve the problem that many existing two-way relay channel (TWRC) estimation methods require the sparse degree of the channel as prior information, we introduced a novel iterative greedy reconstruction algorithm based on compressed sensing (CS), called the sparisty adaptive matching pursuit (SAMP) to reconstruct the channel impulse response under orthogonal frequency division multiplexing (OFDM) system. The most innovative feature of SAMP is its capability of channel reconstruction without prior information of the sparse degree. Under the same condition we compared the algorithm with the other channel estimation methods including conventional least square (LS) algorithm, minimum mean square error (MMSE) algorithm and a orthogonal matching pursuit (OMP) algorithm based on CS. Simulation results show that the proposed algorithm has a better estimation performance and the algorithm improves the utilization of communication resources such as spectrum and energy. Thus it is suitable for real application.