[Show abstract][Hide abstract] ABSTRACT: Wireless sensor networks (WSN) are often applied to monitor the environment such as mine. Due to the rapid attenuation of the wireless signals and the limited power of the WSN nodes, the performances of WSN in these environments are not ideal. In this paper, we present a hybrid radio over fiber wireless sensor network architecture to compensate the weakness of traditional WSN architecture. Considering the remote antenna unit of radio over fiber as a heterogeneous cluster sink node of the WSN, this paper investigates the impact of different rules and behaviors of remote antenna unit on the hybrid architecture. Analyses and simulation results show that a suitable number of remote antenna units can significantly reduce the network delay, energy consumption and improve the practicability of the WSN.
Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007. International Conference on; 10/2007
[Show abstract][Hide abstract] ABSTRACT: In this paper, we consider the problem of how to measure the reliability of the large-scale wireless sensor networks, which is a fundamental requirement of wireless sensor networks deployment. Sensing coverage and network connectivity are key QoS requirements of wireless sensor networks, while network lifetime based on energy efficiency and invulnerability based on fault-tolerance are two main factors to measure network reliability. Therefore a novel reliability model to prolong the network lifetime and improve robust ability of wireless sensor network is proposed in detail, which is based on certain K-coverage and K-connectivity constraints in order to support different QoS requirements with various applications or environments. Afterwards, a wireless sensor network example is simulated in the article to validate the reliability model, and the relationship between reliability value and sensor density is studied further. Topology control algorithm with this reliability model as optimization objective is under working
Wireless Communications, Networking and Mobile Computing, 2006. WiCOM 2006.International Conference on; 10/2006
[Show abstract][Hide abstract] ABSTRACT: The characteristics of radio over polymer optical fiber (RoPOF) are evaluated for indoor or in-building wireless coverage. The frequency responses and the third order intermodulation distortion products of the RoPOF link are investigated. The eye diagrams and EVM values of signals carrying quadrature-phase-shift-keyed (QPSK) data and global system for mobile (GSM) signals are measured to evaluate the transmission performance. The interference measurements with FDM are also carried out. The results show that although the nonlinear distortion and power loss deteriorate the system to some extent, making use of passband transmission, RoPOF can provide fairly good transmission performance for wireless applications.
[Show abstract][Hide abstract] ABSTRACT: In this paper, we proposed an approach for Quality of Service (QoS) routing algorithm of Wireless Sensor Networks (WSNs) based
on Ant Colony Optimization (ACO). The special characteristics of WSNs need to reduce the computational complexity and energy
consumption of the QoS routing algorithm especially. We note that ACO algorithm using collective intelligence of artificial
ants as intelligent agents is very appropriate to solve the combinatorial optimization problems in a fully distributed way,
so in this paper we use modified ACO approach to solve Delay Constraint Maximum Energy Residual Ratio (DCMERR) QoS routing
problem of WSNs. The QoS routing solution proposed in this manuscript, which is named as ACO based QoS routing algorithm (ACO-QoSR),
searches for the best paths, which are satisfied with the QoS requirements with intelligent artificial ants. To overcome the
problem of limited energy in WSNs, there are some modifications to enhance ACO’s convergence rate. ACO-QoSR algorithm is the
tradeoff between a certain guaranteed QoS requirements and acceptable computational complexity. The simulation results verify
that ACO-QoSR algorithm can reduce the selected paths’ delay and improve the selected paths’ normalized energy residual ratio
at the similar levels of routing overhead.
Ubiquitous Intelligence and Computing, Third International Conference, UIC 2006, Wuhan, China, September 3-6, 2006, Proceedings; 01/2006
[Show abstract][Hide abstract] ABSTRACT: Orthogonal frequency division multiplexing (OFDM) signal has a large peak-to-average power ratio (PAPR). Hence, several techniques have been proposed to reduce the PAPR. Clipping is a widely used technique to reduce the peak amplitudes by nonlinearly distorting the OFDM signal at or around the peaks. However, clipping results in symbol distortion because of the nonlinearly operation to the signal peak value. Recently, a DFT-based method for OFDM system to compensate for the performance degradation has been proposed. In this paper, we investigate the hybrid method which consists of RS coding and least square method. Through computer simulation, our results show that the hybrid method is an effective technique to mitigate the clipping distortion
[Show abstract][Hide abstract] ABSTRACT: Mobile nodes in mobile ad-hoc networks (MANETs) operate on limited batteries, so it's a very important issue to use energy efficiently and reduce power consumption. To maximize the lifetime of an ad-hoc network, it is essential to prolong each individual node's life through minimizing the transmission energy consumption; some minimum energy routing schemes in MANETs have been developed for this reason. In this paper, a novel minimum energy routing scheme based on the mobile node's energy consumption and the hierarchical node's congestion levels, which is named RED based minimum energy routing (REDMER) scheme, has been presented. REDMER distinguishes node's congestion levels according to the principle of the well-known AQM (active queue management) scheme RED (random early detection). The simulation results verify that the performance of the REDMER scheme is better than the existing minimum energy routing scheme MTPR (total transmission power routing).
Wireless Communications, Networking and Mobile Computing, 2005. Proceedings. 2005 International Conference on; 10/2005
[Show abstract][Hide abstract] ABSTRACT: A 4-bit optical true-time-delay feeder incorporating an integrated electro-absorption modulation distributed feedback (DFB)
laser for X-band phased array antennas is demonstrated. The integrated electro-absorption modulation DFB laser is an attractive
device that provides a very compact, low-cost solution for optical true-time-delay systems. The variable delay line is constructed
by cascaded magneto-optic switches, which have fast switching speed. The integrated electro-absorption modulation DFB laser
system shows high signal-to-noise ratio up to 58dB, and the transmission performance of the system is relatively good and
International Journal of Infrared and Millimeter Waves 09/2005; 26(10):1465-1472. DOI:10.1007/s10762-005-8444-1 · 0.67 Impact Factor