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Mobile grid is a large-scale distributed network,in which nodes are divided into multiple cluster in order to facilitate management. Physical scope and the number of clusters are important factor affecting division,and they are contradict. It is necessary to strike balance between them when nodes are clustered. In this paper, formal description of nodes clustering is presented and genetic algorithm...
The equipment maintenance for marine ships is of upmost importance especially in a long-distance voyage. This problem becomes more challengeable as the numbers and sorts of equipments become much larger in very large ships. Traditional on-board equipment maintenance heavily relies on a technology called IETM (Interactive Electronic Technical Manual). However, traditional IETM technology has several...
The ISA100.11a standard defining wireless systems for industrial automation and control applications has been released by the international society of automation recently. ISA100.11a readopts the CSMA/CA mechanism of the original IEEE 802.15.4 for contention transmission purpose combined with TDMA-MAC scheme to provide deterministic services. This paper evaluates the performance limits of the CSMA/CA...
Based on the imperfect channel state information (CSI) from noisy channel estimation, the performance analysis of OFDM systems with continuous-rate adaptive modulation (AM) and imperfect estimation in Rayleigh fading channels is presented. Subject to a target bit error rate (BER) constraint, the average spectral efficiency (SE) of the system with imperfect CSI is analyzed and derived, and the conditional...
This paper proposes a novel hybrid CDMA-IDMA collision arbitration protocol for mobile RFID system. The aims of the proposed protocol are: (1) to prevent collisions among mobile readers; and (2) to avoid collisions for active tags. In the proposed protocol, In reader-to-tag downlink communication, we use CDMA technique to identify reader network; in tag-to-reader uplink communication, we use interleaver...
In this paper, the applied MIMO based on Hadamard transform in IEEE 802.16 WiMAX system is proposed. After modulation process, the two points of constellation are merged into one new symbol by Hadamard transform. The result of the addition of two constellations is transmitted through first antenna and the result of the reduction of two constellations is transmitted through second antenna. System model...
In this paper, a new suboptimal tone reservation (TR) algorithm with fixed phase rotation method based on Constant Amplitude Zero Auto-Correlation (CAZAC) sequence is proposed to reduce peak-to-average power ratio (PAPR) in multicarrier code division multiple access (MC-CDMA) systems. To decrease tone searching complexity of TR method, CAZAC sequences is utilized as initial tone candidates. To reduce...
Understanding spatial and temporal dynamics of mobile internet services in cellular data network can be of great help to network management and service provisioning. To this end, we conduct the detailed measurement analysis of spatial and temporal dynamics from point of view of traffic generated by subscribers. The analyzation is based on a large-scale data set collected from a commercial ISP covering...
Providing scalable and robust time synchronization among nodes is one of the challenges for designing and operating a large scale wireless sensor network. In this paper, a novel algorithm based on Kalman-consensus filter is proposed to achieve accurate time synchronization in multihop wireless sensor networks. The proposed approach does not need to select a reference node or construct a spanning tree...
Due to the characteristics of anti-frequency selective fading and supporting high data rate effectively, orthogonal frequency division multiplexing (OFDM) has been widely considered as a key technology for the next-generation mobile communication systems. In this paper, we focus on sub-carrier allocation and utilization in the OFDM access (OFDMA) relaying network, and propose two efficient resource...
In this paper, we address the joint precoding design at both the relay and destination nodes for non-regenerative multiple-input multiple-output (MIMO) shared-relay systems. The minimum mean-squared error (MMSE) of symbol estimation at the destination nodes is adopted as our design criterion. In particular, for the two decoding schemes which are the separate decoding scheme and the joint decoding...
Considering the problem that the well-known bit-reversal algorithm is only fit for radix-2 Fast Fourier Transform (FFT) data reordering, a novel approach based on recursive indexing is proposed for radix-r FFT data reordering. The proposed scheme discards a look-up table required by bit-reversal algorithm. The corresponding hardware structure only costs a RAM whose depth is equal to the size of FFT,...
During the past decade, stream data mining has been attracting widespread attentions of the experts and the researchers all over the world and a large number of interesting research results have been achieved. Among them, frequent itemset mining is one of main research branches of stream data mining with a fundamental and significant position. In order to further advance and develop the research of...
A Sybil attack refers to a network attack against identify in which a malicious user obtains multiple fake identities and creates fake nodes which are inserted amongst honest nodes in the system simultaneous. By controlling a large percentage of the system, or a large section of the local scope, the malicious user can take further boring actions like DDos attacks, False Voting, Invalid DHT routing,...
Energy consumption is arguably the key factor in the design and operation of Wireless Sensor Networks (WSNs). This holds both for normal operation and maintenance operations - such as software updates. Whereas software updates will probably be infrequent, they must still not consume a significant fraction of a WSN's energy reserve; also, the required consumption must be known before triggering an...
This paper describes the design and implementation of low power modular multiplier of RSA and balances its area and speed. By improving Montgomery modular multiplication algorithm, optimizing critical path and using several low power methods, this paper achieves low power as well as high speed performance. The design is implemented using SMIC 0.13um CMOS process, the average power consumption is 106uW...
Network coding is a promising technology which can improve the network resource utilization and network throughput effectively. Because of the broadcast procedure for network coded packet and the different link qualities between destination nodes and relay node, the selection of destination node as the configuration standard for the broadcasting of network coded packet gives direct effect towards...
MIMO radar is a new radar technology proposed recently. On the transmitter, each channel radiates a omnidirectional and orthogonal waveform. On the receiver, the return signals are processed through a bank of matched filters to separate each transmitted signals. Hence, the orthogonal performance between signals is crucial for implementing MMO radar system. This paper presents the concept of Orthogonal...
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