Applied Mechanics and Materials Vols. 475-476

Abstract: The paper presents development of System SMPSL for binary communication. System SMPSL is computer system for measurement used in the school laboratory. The system is very cheap to assemble the hardware and available software is for free. The system consists of hardware and software parts. The communication is performed using library. The paper describes the basic connections and the source code for creating custom measurement system using a computer. Presented SMPSL system was developed based on mentioned basis.

Abstract: Femtocell is one of the promising solutions that can improve the energy efficiency of cellular network. However, densely and randomly deployed femtocells may experience server inter-femtocell interference due to rough-and-tumble spectrum reuse with unconstrained power. In this paper, the downlink power control problem is investigated to achieve an energy efficient power allocation scheme. The problem is formulated as a non-cooperative game and distributed power control algorithm is proposed. Numerical results suggest that a good energy efficiency improvement is acquired and the algorithm converge within a few iteration times.

Abstract: D2D communication can facilitate diverse local services and ease the load of base station. However, traditional resource allocation schemes for D2D communication were simply aiming at maximizing the sum-rate capacity or minimizing the mutual interference of the system but ignoring users satisfaction, which were discussed usually under the premise that the system resource was sufficient for the fixed number of users or restricted in the flexibility of spectral reuse. In the resource constrained system, aiming at maximizing average system satisfaction degree, a more flexible resource allocation scheme based on optimized artificial fish swarm algorithm (USRA-AFSA) is proposed in this paper, in which user satisfaction degree models are established and different D2D links are allowed to coexist on the same subchannel. With solutions mapped onto artificial fish, the simulation results show that the proposed scheme achieves higher average system satisfaction degree and larger system throughput compared with other schemes.

Abstract: We introduced an improved singular value decomposition (SVD) channel estimation algorithm for multiple-input multiple-output (MIMO) wireless communication system. The algorithm is supposed to solve the issue that the channel estimation result is not accurate when the training sequences have some 0 elements. The improvement is also applicable in the other channel estimation algorithms. We made some comparisons between the linear least squares (LS) and the linear minimum mean square error (LMMSE) channel estimation, the traditional singular value decomposition and the improved SVD algorithm to demonstrate the efficiency. Results show that the proposed improved SVD algorithm has better performance in mean square error (MSE) and bit error rate (BER) of channel estimation and the estimated values approach the actual channel state.

Abstract: A single frequency network (SFN) based on the DTMB (Digital Television Terrestrial Broadcasting System) terrestrial digital television (DTV) system normally causes interference among signals from multiple transmitters in the network. These transmitters should broadcast the same program at the same frequency simultaneously in the service area. To meet the SFN network construction requirements in complex transport situation, TS distribution networks synchronization is one of the most important foundations. A design was proposed to insert into each MPEG-TS (SIP) packet with one absolute timestamp in the SFN adapter, which was proved to be valuable insuring the synchronization of the SFN TS distribution through field-test in Ningxia DTMB network.

Abstract: One of the choke point of AD HOC network is that the system hasnt resolved the problem of QOS in the MAC layer, the MAC layer QOS of AD HOC network is divided into two levels, one is flow level, and the other is node level. In order to solve QOS problem, this paper proposed a new algorithm IMSMAC, the algorithm use penalty function to optimize the value of different level of service in flow level, and use different priority backoff index to different node in node level. Analysis the throughput and delay of IMSMAC and DCF in NS2, the result showed that the high priority service have a certain degree of improvement in throughput and delay in IMSMAC algorithm.

Abstract: Most of college campus network to access the CERNET and CHINANET and CNC, respectively, more than export way access to the Internet. How to effectively use more export resources, improve the network speed and reliability aspects worthy of in-depth study, etc. In this paper, a model of campus network, combined with DNS service program of the new features and rational deployment of how many export server in the network domain name, put forward a reasonable solution.

Abstract: According to the existing status of civil aviation enterprises office network, this paper brings up a project to combined RFID and the VPN network which have been provided by the original system, by adding a RFID server. It bases on VPN technology to form a RFID intelligent aviation material management information system, without affecting the function of the original office network. The system is able to locate the material position in the warehouse and improve the level of the management on civil aviation material information.

Abstract: Wireless network makes up the wired network shortcomings. With the popularity of the WiFi terminal, wireless network brings convenience, at the same time, the security threats are constantly upgrading, and the security issues have been plaguing the legitimate user. Wireless network security is not only with authentication, encryption, integrity testing and other technology-related, but also need intrusion detection systems, firewalls and other technology cooperation, so its a multi-layered problem. Not only the network administrator needs to take security measures to protect the network and comprehensive safety inspection, but also requires the users to enhance their network security awareness.

Abstract: Despite of a collection of Quality of Service (QoS) guarantee protocols, no one is able to perform adaptively due to the application dependent nature of those proposed QoS provision algorithms. In this paper a new adaptive model, termed AHP-TOPSIS, is employed to evaluate the performance of two routing protocols DSR and DSDV, based on which the system is capable of switching to the optimal protocol adaptively. The efficiency of the AHP-TOPSIS model is validated by extensive simulations.