Applied Mechanics and Materials Vols. 347-350

Abstract: In the flat Rayleigh channels of linear cell, two distributed receive antennas are employed to receive the signal transmitted from the mobile station (MS) with a single antenna. We exploit the false alarm probability at the central processor to guarantee that the false alarm probability at each distributed antenna does not exceed the pre-defined probability of false alarm. Based on the exploited probability of false alarm at the central processor, a cooperative detection threshold of each antenna is derived for threshold detection. According to the threshold detection, a maximum-likelihood (ML)-based timing acquisition method is proposed for distributed antenna systems (DAS). Without increasing the pre-defined probability of false alarm, the analysis and simulation results show that the correct acquisition probability and the missed detection probability for each distributed antenna can be improved with the proposed method wherever the MS is located.

Abstract: Retracted paper: To spread IPv6 to the end of the networks, it is necessary to construct networks used for small organizations. In fact, few researchers would disagree with the understanding of active IPv6 networks, which embodies the private principles of cyber informatics. In this paper, we discuss the methodology to construct IPv6 networks for small organizations.

Abstract: This article has analyzed the insufficiency of the traditional teaching administration system, proposed that through inserts the way of regulation storeroom to realize in the procedure active database-based the teaching administration system, through the practical research showed that this system can provide the real-time, all-round service on own initiative, and active service mechanism is highly effective, feasible In this paper, it studies one of the error check cont rols of the communications of computers network . Cyclic Redundancy Check ( CRC ) . It introduces the principle of CRC, the algorithms of CRC, the algorithms analysis of CRC, the program of CRC and the functions & features of CRC. The algorithms of CRC need not to design circuit of hardware in addition. It improves the speed of the communications of computer s network an d checks the message correctly.

Abstract: The network service applications based on socket have been widely used, however it is still difficult to realize network service application program with a large amount of data and connections. This paper describes the principle of completion port, and based on this, analyses and introduces the various steps to achieve completion port and describes the usage of key functions in detail. Finally the client and server are simulated for the testing. The results show based on the I/O completion port technology the server application can get a good expansibility.

Abstract: In this paper the classification and development of server load balancing technology are briefly described and the load balancing algorithms based on server cluster are compared. A server load balancing technology and algorithm based on multiple parameters are proposed. Finally, the load balancing algorithm is tested. Testing results show that the method is feasible.

Abstract: ZigBee routing protocol study and optimization for the problem of the effects of flooding AODVjr algorithm RREQ packet.By introducing new coordinate parameters and other methods to control the RREQ packet forwarding. Network robustness problem and prolong the life of the network, by changing the algorithm in the case of low energy strategy.And simulation comparison to verify the effectiveness of the optimization algorithm.

Abstract: Recently mobile network technologies develop quickly. To meet the increasing demand of wireless users, many multimedia proxies have been deployed over wireless networks. The caching nodes constitute a wireless caching system with an architecture of P2P and provide better service to mobile users. In this paper, we formulate the caching system to optimize the consumption of network bandwidth and guarantee the response time of mobile users. Two strategies: single greedy caching strategy and cooperative hybrid caching strategy are proposed to achieve this goal. Single greedy caching aims to reduce bandwidth consumption from the standpoint of each caching node, while cooperative hybrid caching allows sharing and coordination of multiple nodes, taking both bandwidth consumption and popularity into account. Simulation results show that cooperative hybrid caching outperforms single greedy caching in both bandwidth consumption and delay time.

Abstract: As CMA blind equalization algorithm based on stochastic gradient descend method has slow convergence rate and big steady state residual error, a robust memory gradient blind equalization algorithm based on error sign decision was proposed. Compared with stochastic gradient algorithm, memory gradient algorithm can make full use of the iteration gradient information of current and last step to accelerate convergence speed and effectively avoid the error convergence algorithm to a certain extent. However, transient noise interference may result in inconsistent direction of current iteration gradient information and last step that may cause the algorithm unstable, if the iteration error sign decision of current and last step is consistent then adopts memory gradient stochastic gradient descent algorithm, this method can ensure the robustness of memory gradient algorithm .The computer simulation results prove the validity of the algorithm.

Abstract: Spectrum sharing technologies can achieve the maximum usage of spectrum resources flexibly and high-efficiently, which relieves the current spectrum crunch situation availably. In a multi-hop cognitive wireless mesh network scenario coexisting with a TDMA/FDMA cellular network, an effective scheme of cross-layer design between link-layer spectrum decision and network-layer routing is proposed, on the basis of the combination of spectrum underlay and spectrum overlay. Simulation results verify that the scheme outperforms distinctly the shortest path based random spectrum decision algorithm on network end-to-end performance.

Abstract: With the dramatic increase in amount of information in campus network, the security and high reliability of access data have become urgent requirements on redundancy reliability design of campus network. This paper adopts the technology of VRRP and takes advantages of double backup sets and router to process the design and configuration. As is shown in the experiment, when one device fails, the other ones can still complete relevant operations under the conditions of double backup sets. Therefore, the redundancy reliability design of campus network can be realized through the technology of VRRP double backup sets.