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Abstract: Wireless LANs networks are more vulnerable to security attacks due to their broadcast and open nature features. How to provide an end-to-end security commutation for two parties in wireless LAN networks is a challenge to researchers. Traditional identity-based authenticated key exchange protocol is unsuitable to wireless network due to the limitation bandwidth and lower computation. In order to address issue, we, in this paper, proposed an efficient authenticated key exchange protocol for wireless LAN networks using Elliptic curve cryptography techniques. In addition, security analysis is also covered in this paper. [Copyright &y& Elsevier]

Abstract: Trellis coded modulation (TCM) combined with continuous phase modulation technique can be achieved high power and bandwidth efficiency. Frequency offset between a transmitter and a receiver is the most encountered problem in wireless communication systems. In this paper, we designed particular preamble bits for our TCM-CPM system, and then proposed a frequency offset estimation algorithm which need coarse estimation and fine estimation. The frequency offset can be estimated from the direct current component of Fast Fourier Transform (FFT). Simulation over AWGN channel demonstrate that the proposed algorithm can estimate the frequency offset precisely and can be applied in large Doppler frequency shift and high SNR environment. [Copyright &y& Elsevier]

Abstract: This paper presented a high speed storage system for real-time application. The hardware of system mainly consists data distribution, transmission, storage and integration section. By using high-speed FPGA, the original data stream will be distributed into four streams firstly. Then each data stream will be transferred to a computer and stored in a solid-state storage card. Four stored streams are merged during read back process finally. In aspect of software, implementation methods of DDR3-based FIFO, PCI-E DMA controller, Aurora and NAND flash controller were introduced in detail. System evaluation results show that system achieved high transmission bandwidth and storage speed (up to 3.2GB/s). [Copyright &y& Elsevier]

Abstract: With the rapid expansion of data amount, it is becoming more and more crucial to improve the utilization of storage space and bandwidth for online backup service system. De-duplication is an effective measure for eliminating redundant data to enhance storage space efficiency. This paper presents a backup service system with log-based deduplication and consistency guarantee, called LBDC, which breaks files into blocks, each block is indexed and addressed by hashing its content, so as to avoid redundant block transferring during backup process, meanwhile log mechanism is proposed to ensure data consistency. Experimental result demonstrates that LBDC can accomplish effective online de-duplication and data consistency. [Copyright &y& Elsevier]

Abstract: The newest international video coding standard H.264 is very efficient in solving the limited bandwidth problem and improving the quality of reconstructed image. Although H.264 has many potential application fields, the big computation complexity becomes a bottleneck for its real time applications. In this paper, we proposed a fast mode decision algorithm of 4x4 block intra prediction to optimize the H.264 encoder. Experimental results show that it can reduce the computational complexity of the H.264 encoder remarkably at the expense of little quality degradation. [Copyright &y& Elsevier]

Abstract: This paper proposed an optimization based on artificial fish swarm algorithm and tabu search algorithm combining QoS multicast routing algorithm for the bandwidth limited of the delay multicast routing problem, The algorithm can quickly search for the lowest transmission cost multicast routing tree. The simulation results show that the algorithm with some commonly used algorithms have higher bandwidth compared to satisfaction and delay satisfaction, and has better performance of global optimization. Suitable for high-speed, real-time multimedia transmission network. [Copyright &y& Elsevier]

Abstract: Based on the CMOS SMIC 0.18um technique, this paper presents a high-performance folded cascode amplifier, which replaces the traditional telescopic structure with the classic cascode structure. Through the Spectre simulation of Cadence, under 3.3 V, the circuit''s DC gain is as high as 96.29 dB, and the phase margin is 83.5 degree with a high stability; the bandwidth gain is larger than 5 MHz, the power consumption is smaller than 0.1mW. [Copyright &y& Elsevier]

Abstract: To face the challenge of the high data throughput requirements for modern communications, extensive researches have been paid to broadband modulation. Multi-carrier modulation is one of the most important broadband modulation techniques. Orthogonal frequency division multiplexing (OFDM) is an effective multi-carrier modulation technique for combating radio channel multipath fading and for high-bit-rate transmission over wireless channels and it is extensively used in modern digital television terrestrial broadcasting (DTTB) systems to support high performance bandwidth-efficient multimedia services. The technique of multiple antennas at the transmitter and at the receiver permits several fold increase in achieved data rates and spectral efficiency through spatial processing and the use of multiple transmit antennas and multiple receive antennas. The Chinese DTTB system with multiple-antenna receiver is considered. Chinese digital television terrestrial broadcasting standard recommends three kinds of Frame Head mode with PN420/PN595/PN945 as training sequences for the time domain synchronous OFDM (TDS-OFDM) based DTTB systems. At receiver side, Frame Head mode detection should be done. In this paper, a Frame Head mode detection scheme is proposed for the multiple-antenna receiver of the Chinese DTTB system. System performance studies under different channel situations are used to verify the efficiency of the proposed scheme. [Copyright &y& Elsevier]

Abstract: Due to the efficiency of mitigation multipath delay spread and being well suited for wideband transmission, orthogonal frequency division multiplexing is extensively used in the wireless local area network domain. Orthogonal frequency division multiplexing is an effective technique for combating radio channel multipath fading and for high data throughput transmission over wireless channels and it is extensively used to support high performance bandwidth-efficient multimedia services. The technique of multiple antennas at the transmitter and at the receiver permits several fold increase in achieved data rates and spectral efficiency through spatial processing and the use of multiple transmit antennas and multiple receive antennas. High accuracy of the channel estimation scheme is important for the broadband multi-carrier orthogonal frequency division multiplexing multiple-antenna system and is crucial to the performance of the overall orthogonal frequency division multiplexing multiple-antenna system in terms of the symbol error rate. In this paper, a channel estimation scheme is proposed for the orthogonal frequency division multiplexing based multiple-antenna wireless local area network systems. [Copyright &y& Elsevier]

Abstract: As an effective technique for combating multipath fading and for high data throughput transmission over wireless channels, orthogonal frequency division multiplexing is extensively used in modern digital television terrestrial broadcasting systems to support high performance bandwidth-efficient multimedia services. The multiple-antenna broadband multi-carrier orthogonal frequency division multiplexing systems increase diversity gain and enhance system capacity on a time varying multipath fading channel. Accurate channel estimation is important for the application of simple channel equalization and decoding for the multiple-antenna broadband multi-carrier orthogonal frequency division multiplexing systems and the accuracy of the channel estimation is crucial to the performance of the overall orthogonal frequency division multiplexing multiple-antenna system in terms of the symbol error rate. In this paper, a channel estimation scheme is proposed for the multiple-antenna receiver of the time domain synchronous orthogonal frequency division multiplexing based multiple-antenna Chinese digital television terrestrial broadcasting systems. [Copyright &y& Elsevier]

Abstract: A smart power system demands a strong and self-healing communication system with greater capacity. In China, as the ultra high voltage transmission lines and large scale interconnected grids are expanding throughout the nation, disaster-tolerant communication network is essential for reliable system operation and control. In this paper, we propose a hybrid communication network utilizing both terrestrial and satellite links to improve the system reliability. The adaptive link selection protocol at network layer is developed to facilitate the network integrity. A modification of transport protocol over satellite communication is also proposed to better exploit the limited bandwidth resources. The performance analysis and field trial of the proposed scheme based on the practical network configuration in Sichuan power grid is thoroughly studied. The results showed a great bandwidth saving of satellite resources without loss of network integrity. [Copyright &y& Elsevier]

Abstract: In this paper, a distributed amplifier with adjustable gain control is designed based on 0.15um GaAs PHEMT which consists of nine gain cells, and the novel cascode structure is adopted to extend the output voltage and bandwidth. The amplifier provides 16dB high gain with only 2.5dB noise figure in a wide band from 2 to 24GHz and the gain flatness is excellent±0.2dB from 3.5-23.5GHz. An optional gate bias is specially designed to allow greater than 10dB gain control range. The circuit requires only 60mA from a+5V supply and the area is 2.36*1.01mm2. [Copyright &y& Elsevier]

Abstract: The cross coupled microwave filter is widely used in the communication sub system .The synthesis of the cross coupled filter is from prescribed transmission zeros and return loss till the attainment of the coupling matrix of each cavity. A compact narrowband combline high rejection filter with cross coupled is presented. A configuration using identical resonator post with capacitance-loading is introduced. Tested results show that with order-8 filter center frequency at 2017.5MHz, return loss lower than -25dB can be achieved over a relative bandwidth of 1.29%. Sample filter has been fabricated and tested result confirmed the theory results. In this paper, tested results will be given to illustrate the concept. [Copyright &y& Elsevier]

Abstract: In this paper, we propose an enhanced TCP protocol aiming at improving efficiency in heterogeneous networks while maintaining friendliness to existing protocols, such as NewReno. This scheme, named TCPW-AA, uses the idea of congestion control algorithm in TCP-Westwood and a totally different bandwidth estimation method based on an unbiased technique TIBET. We make some improvement to achieve good tradeoff between efficiency and friendliness. Simulations on ns2 and comparisons with TCPW, TIBET and NewReno show its advantages and effectiveness. [Copyright &y& Elsevier]

Abstract: To the current problems in SCM experiment teaching, the necessity and principles of experiment reform are analyzed in this paper, and an experiment board is designed based on ISP download line. It presented the general structure diagram of the system, described the hard circuit and software design in details, and introduced the programming method with an example. This devices has the advantages such as low cost, easy to use and easy to carry, et al.. The practice showed that the device can greatly increase the student''s interest in SCM learning, so it can provide a good solution for experiment reform. [Copyright &y& Elsevier]