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The reconfigurable optical add/drop multiplexer (ROADM) has become one of the most important elements in the DWDM network. The next generation multi-degree ROADM requires two main features: colorless and directionless. Colorless means that add/drop ports are not wavelength specific, and directionless feature enables any transponder to be connected to any degree. In this paper we review and analyze...
Advances in device technology and dense wavelength division multiplexing have enabled modern optical backbones to provide high data rate services in a cost-effective manner. At the same time, applications are emerging with the potential to leverage these capabilities for short time spans: load migration for Internet clouds, integrated computational grids, and remote surgery. Until such applications...
This paper studies the necessary and sufficient nonblocking conditions for multicast Clos network or v(m, n1, r1, n2, r2) network, wherein there are r1/r2 switch modules at first/third stage, n1 input/n2 output ports on each first/third stage switch module, and m central stage modules. We prove that given constant n1, n2, if r1 ≥ L = n2 ((n2-1m)-1)+1, r2 ≥ n1n2(n2L), m ≥ n1n2 is a necessary and sufficient...
This paper studies the performance of Non-persistent CSMA protocols using K-Exponential Backoff collision resolution algorithms. We model it as a multi-queue single-server system with infinite buffer size and consider the service time distribution of Head-of-line packets as a Markov Chain to get the network throughput as well as the stability. The stable region of retransmission factor q is illustrated...
The paper investigates the influence of the amplitude spatial filtering of the launched light beam on the base-band width of MM fiber frequency response. The filter is located on the confocal plane of an 4f imager. It is shown both theoretically and experimentally that a substantial increase of 3 dB base-band frequency is possible with only moderate filtration losses.
In this work, wavelet de-noising with several different types of wavelets such as db4, coif4 and dmey wavelets was applied at the end of the multi-span intensity-modulated fiber communication systems. The results of numerical simulations carried out in different fiber links demonstrated that the wavelet de-noising method could remove the random amplitude fluctuation and pulse breaking induced by the...
Piggybacking communication by illumination LEDs provides additional valuable functionality to LED lighting fixtures as optical communication transmitters at little cost. However, joint dimming control and high data-rate communication requires proper supporting protocols under the bandwidth limitation of LEDs. This paper applies overlapping pulse position modulation (OPPM) to achieve high capacity...
In Ad Hoc network, all the network functions count on node cooperation. Forwarding packets of other nodes is a basic example of such cooperation. However, nodes may not be interested in forwarding the requesting packets due to selfish or malicious reasons, which significantly degrades the network performance. Therefore, in respect of node forwarding process, we propose a global punishment-based repeated-game...
In this paper, the local features obtained from the signature has been used to create the texture image based on the spatio-temporal correlation matrix. The Gabor wavelets exhibit desirable characteristics of spatial locality and orientation selectivity, and are optimally localized in the space and frequency domains. So it has been chosen to extract the Gabor features of the image. Signature is a...
High peak-to-average power ratio (PAPR) is one major drawback of orthogonal frequency division multiplexing (OFDM) systems. Recently, the constellation extended scheme (CES) is an active technique for reducing PAPR of OFDM signals. However, this approach needs high computational load and more inverse Fast Fourier transform (IFFT) operations for finding the transmitted signal with minimum PAPR out...
The coupling behavior between two parallel micro/nano-fibers is investigated by extending the theory of transmission-lines (TL) to optical domain, Simulation result indicates that the energy transfer length of micro/nano-fibers based coupler is much shorter than that of conventional fiber based coupler. The experiment of the coupling behavior of micro/nano-fibers is demonstrated. It verifies the TL...
In this work, we present Media-Aware Workflows, an extension to Business Process Management Systems (BPMS) and Service Oriented Architecture (SOA) middleware for automating media workflows. The combination of SOA and BPMS technologies provides a robust architectural approach for integrating and orchestrating the multiple heterogeneous systems involved in enterprise-level workflows. However, media-intensive...
The boom in user amount and voice traffic puts a huge pressure on the operators especially within populous countries, which forces them to enhance the voice capacity in the GSM evolution. The concept of Multi-User Reusing-One-Slot (MUROS) is promising to resolve this problem with negligible impact on handsets as well as to networks. In this paper, we compared the link-level and system-level performance...
In optical coherent receivers, the timing error detector in synchronization loop can't detect timing errors properly from signals distorted by large dispersion and the signal processing rate in the loop is very difficult to reach required 56GHz in the 112 Gb/s PM-(D)QPSK system because of the limit of current electronic circuits. This paper proposes a novel parallel processing VCO clock synchronization...
This article proposes and implements a survivable Ethernet passive optical network (EPON) system supporting direct communication between optical network units (ONU) without optical line terminal's (OLT) forwarding. An original centralized automatic protection switching (APS) control mechanism is proposed and implemented by FPGA. The actual test results show that our system's protection switching time...
In order to break the maximum symbol rate processed with real-time implementation limited by the speed of electric digital signal processors, we propose a novel scheme of adaptive dispersion equalization, which supports parallel processing, so it can deal with a very high aggregate bit rate, such as 100Gb/s and above, at low operating rate of hardware. Finally, its good performance is demonstrated...
We study the problem of cooperative transmission, relay selection and scheduling in battery-operated wireless networks, where energy efficiency is a critical design consideration. We assume that multiple relay nodes in the network can cooperate their transmissions of information to gain energy savings in a distributed network MIMO system. We formulate the problem as maximizing the lifetime of the...
EPON and WiMAX Convergence Network integrates the “master-slave and peer-to-peer combined” EPON network structure that supports protection switching with the WiMAX technology. Directing at the complicated architecture and various types of topology of the convergence network, this article proposes an automatic discovery method and a layout algorithm for network topology to facilitate the network management...
This paper presents the design of a Class AB power amplifier (PA) for 2.4-2.4835GHz Wireless Sensor Network (WSN) system in 0.13μm CMOS technology. The PA adopts the single-stage differential structure and the output power of the PA can be controlled by switching the sizes of transistors. The proposed PA achieves a power added efficiency (PAE) of 25.34% while delivering an output power of 7.92dBm...
It is important to support the multicast in the OTN network since multicast services are becoming more popular and multicasting will result in the improvement of resource utilization rate. To support multicast in a cost-effective way, the multicast of OTN should be realized in electronic domain based on ODU-level rather than optical domain in our point of view. In order to implement multicast routing...
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