The Experts below are selected from a list of 4149 Experts worldwide ranked by ideXlab platform

M. Meenakshi - One of the best experts on this subject based on the ideXlab platform.

  • Wavelength conversion and in-band crosstalk in WDM optical networks
    Journal of Optics, 2009
    Co-Authors: V. Saminandan, M. Meenakshi
    Abstract:

    Wavelength-routed all-optical networks have emerged as a popular architectural solution for wide area networks and are being conceived for future broadband communications. Call Connection probability in such networks depends on the number of WDM wavelengths employed and on the capability for wavelength conversion at network nodes. Equipping all the network nodes with wavelength conversion capability to reduce the blocking probability is not a cost effective solution due to the high cost of wavelength converters (WC). Hence, networks equipped with converters at only some of the nodes are more practical. However, these nodes should be identified optimally so that network blocking probability is minimized. In this paper, wavelength converters based on four wave mixing (FWM) in semiconductor optical amplifiers (SOAs) is considered. In WDM all-optical networks, in-band crosstalk is regarded as one of the major transmission impairments. In-band crosstalk usually arises when multiple signals at identical or adjacent wavelengths pass through an optical crossconnect node. In-band crosstalk leads to increased receiver BER. This paper considers in-band crosstalk arising in a network which is equipped with wavelength converters. For every dynamically arriving Connection Request, a route is determined using Dijikstra’s algorithm and a free wavelength is determined using the random wavelength assignment. If no common free wavelength is available, Connection is tried using wavelength converters, if available, on the given route. If wavelength assignment does not succeed, the call is blocked. If wavelength assignment succeeds, the BER at the destination node is computed before establishing the lightpath. If the estimated BER exceeds 10^−12, the call is blocked. Otherwise, the call is admitted. The results reveal that wavelength converters are not useful in networks that already suffer from crosstalk conditions.

Chunming Qiao - One of the best experts on this subject based on the ideXlab platform.

  • Nonblocking WDM switches based on arrayed waveguide grating and limited wavelength conversion
    Proceedings - IEEE INFOCOM, 2004
    Co-Authors: Hung Q Ngo, Dazhen Pan, Chunming Qiao
    Abstract:

    Constructing fast wavelength division multiplexing switches with cheap, integratable components, less power consumption and noise accumulation, and low complexity is an important problem in optical networking. Typically, there are two Request models widely considered. In one model, a Connection Request asks to go from a wavelength on an input fiber of the WDM switch to a particular wavelength on an output fiber. In the other, a Connection only needs to get to a particular output fiber, irrespective of what wavelength it will be on. In this paper, we give novel constructions of strictly nonblocking and rearrangeably nonblocking WDM switches for both Request models using limited range wavelength converters and arrayed waveguide grating routers. We fully analyze their blocking characteristics. Our designs are all relatively simple and easy to be laid out, consume little power, do not accumulate much noise, and are useful for both optical circuit-switching and optical packet/burst switching. As far as we know, these are the first of such constructions.

  • AIWoRC - Profitable Connection assignment for incremental traffic in all-optical WDM networks
    Scopus, 2000
    Co-Authors: Vishal Anand, T. Katarki, Chunming Qiao
    Abstract:

    In this paper, we investigate the routing and wavelength assignment problem for incremental Connection Requests in all-optical wavelength-division-multiplexed networks, with the objective of maximizing the profit that can be made. Specifically, each Connection Request between a pair of nodes in the network is associated with an earning, which can be obtained by satisfying the Connection Request. Each wavelength on a link is associated with a cost of using that wavelength on that link. We assume that the Connection Requests come in one by one (incrementally) and once a Connection Request is satisfied, the Connection stays in the network for a long period of time. To establish a Connection between a pair of nodes in the network, a path and a wavelength on that path through the network is found, such that Connections whose paths share a common link in the network are assigned different wavelengths. We propose profit maximizing heuristics which try to satisfy the incremental Connection Requests, as they arrive, possibly by re-routing the existing Connections in the network, in a manner which maximizes the over-all profit obtained from the network. The heuristics are then compared with a profit maximizing heuristic, which does not re-route any existing Connections.

Ellen Zegura - One of the best experts on this subject based on the ideXlab platform.

  • Pool-based traffic generation model for SONET/SDH
    Proceedings of GLOBECOM'96. 1996 IEEE Global Telecommunications Conference, 1996
    Co-Authors: Wonbae Park, H L Owen, Ellen Zegura
    Abstract:

    In a SONET/SDH transmission environment, the switching systems must accommodate a hierarchy of traffic and bandwidth. In the design of SONET/SDH cross-connect switching hardware and switching algorithms, it is necessary to evaluate the switching system performance on this hierarchy through simulations. These simulations require the generation of realistic Connection Requests so that the switching system performance may be evaluated. Parameters which are required in such a model include the total load on the switching system, the mix of the various traffic types involved in the Connection Requests, as well as the active and idle times for each of the Connections. This paper presents a traffic Connection Request model that meets these goals in a SONET/SDH environment. The traffic generated by this model may be used in an evaluation of SONET/SDH switching architectures and algorithms.

  • Connection Request model for sonet sdh switch evaluation
    International Conference on Communications, 1996
    Co-Authors: Wonbae Park, H L Owen, Ellen Zegura
    Abstract:

    In the SONET/SDH transmission environment, switching systems must accommodate a hierarchy of traffic and bandwidth. In the design of SONET/SDH switching hardware and switching algorithms, it is necessary to evaluate the switching system performance on this hierarchy through simulations. These simulations require the generation of realistic Connection Requests so that the switching system performance may be evaluated. Parameters which are required in such a model include the total load on the switching system, the mix of the various traffic types involved in the Connection Requests, as well as the active and idle times for each of the Connections. This paper presents a Connection Request model that meets these goals in a SONET/SDH unicast environment.

  • Connection Request model for SONET/SDH switch evaluation
    Proceedings of ICC SUPERCOMM '96 - International Conference on Communications, 1996
    Co-Authors: Wonbae Park, H L Owen, Ellen Zegura
    Abstract:

    In the SONET/SDH transmission environment, switching systems must accommodate a hierarchy of traffic and bandwidth. In the design of SONET/SDH switching hardware and switching algorithms, it is necessary to evaluate the switching system performance on this hierarchy through simulations. These simulations require the generation of realistic Connection Requests so that the switching system performance may be evaluated. Parameters which are required in such a model include the total load on the switching system, the mix of the various traffic types involved in the Connection Requests, as well as the active and idle times for each of the Connections. This paper presents a Connection Request model that meets these goals in a SONET/SDH unicast environment.

Hussein T. Mouftah - One of the best experts on this subject based on the ideXlab platform.

  • Survivable Routing with Dynamic Traffic
    Optical Networks, 2020
    Co-Authors: Hussein T. Mouftah, Pin-han Ho
    Abstract:

    The spare capacity allocation schemes introduced in Chapter 7 either take a specific group of working paths or all working paths into consideration at a time during the optimization process. However, as any Connection Request arrives, an on-line algorithm is still required to allocate it. The on-line algorithm should be able to guarantee derivation of a link- or node-disjoint or link-disjoint working and protection (W-P) path-pair for a Connection Request if any exists. Since the reconfiguration or reallocation of spare capacity in the networks may not be frequently performed, the on-line algorithm of path selection needs to be both computation- and capacity efficient so that networks can accommodate as many subsequent Connection calls as possible without losing the ability to deal with dynamic traffic Requests that arrive one after the other.

  • A dynamic k-routing algorithm in wavelength-routed optical networks
    Canadian Conference on Electrical and Computer Engineering 2004 (IEEE Cat. No.04CH37513), 2004
    Co-Authors: S. Siddiqui, Jing Wu, Hussein T. Mouftah, Michel Savoie
    Abstract:

    Routing in a wavelength-routed network can be static or dynamic. In static routing, routes for each source-destination pair in a network are predetermined, whereas in dynamic routing, a route is computed dynamically for a Connection Request as it arrives in the network. Dynamic routing incorporates current network state in path computation to ensure an optimal path selection. In this paper, we propose an adaptive routing algorithm, a dynamic k-routing algorithm that computes a least cost path for a Connection Request. The algorithm computes at most k paths before a Connection Request is blocked. This paper assumes no wavelength conversion in the network and that the link state information is available to each node in the network. We compare the blocking performance of the proposed adaptive routing algorithm with fixed shortest path routing, fixed alternate shortest path routing and dynamic routing (using the shortest path with available capacity) and show that this algorithm performs better in terms of blocking probability and network utilization.

  • IFF: a novel wavelength assignment scheme for WDM optical networks
    Canadian Conference on Electrical and Computer Engineering 2004 (IEEE Cat. No.04CH37513), 2004
    Co-Authors: A.e. Eshoul, Hussein T. Mouftah
    Abstract:

    This paper investigates the performance of few wavelength assignment schemes used in wavelength-routed WDM networks under dynamic traffic environment. The paper focuses on networks operating under wavelength continuity constraint, in which the same wavelength must be assigned to all the links of the chosen route. We compare the performance of some of the wavelength assignment schemes used and propose a new scheme that performs better in terms of blocking probability, especially as the number of offered wavelengths per fiber increases. This novel scheme avoids assigning the same wavelength to multiple Connection Requests concurrently to reduce blocking caused by reservation conflicts between simultaneous Connection Requests. The improved first fit (IFF) algorithm is based on the first fit wavelength assignment scheme, with a different starting search point for every new Connection Request.

Jawad A Salehi - One of the best experts on this subject based on the ideXlab platform.

  • energy efficient routing and spectrum assignment with regenerator placement in elastic optical networks
    Journal of Lightwave Technology, 2014
    Co-Authors: Ahmad Fallahpour, Hamzeh Beyranvand, Alireza S Nezamalhosseini, Jawad A Salehi
    Abstract:

    In this paper, we present a dynamic energy efficient routing and spectrum assignment algorithm with regenerator placement (RP) capability for elastic optical networks. In this algorithm, a virtual graph is considered for a given network topology graph, whereby the cost functions of virtual graph is computed according to the energy consumption of the corresponding links and intermediates routers. Furthermore, the arrived Connection Request is served by finding the most energy-efficient path among the possible candidate paths. Then, the quality of transmission (QoT) of the selected path is evaluated in terms of bit error rate. If the estimated QoT is higher than a predetermined threshold, the designated path is assigned to the incoming Request, otherwise, the RP algorithm is utilized to place a regenerator at the most energy-efficient position. In addition, the demanded transmission rate and required QoT are fulfilled by assessing different modulation formats and selecting appropriate modulation format in terms of power consumption and blocking probability (BP). We evaluate the proposed algorithms through extensive numerical simulations. The results of simulations reveal that the proposed algorithms have better performance than other existing schemes in terms of network total energy consumption and acceptable BP.