Browsing by Author "Hui, Rongqing"
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Item Digital subcarrier cross-connects (DSXCs)(The University of Texas at Dallas, 2013-06-18) Hui, Rongqing; Huang, Wanjun, 1978; Razo, Miguel; Tacca, Marco, 1973; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Traditional (analog) Frequency Division Multiplexing (FDM) was widely used in the pre-SONET/SDH era, to multiplex transport channels together using spectral diversity. These transport solutions were then gradually abandoned due in part to their low spectral efficiency and with the advent of Time Division Multiplexing (TDM), which lead to synchronous transmission techniques, such as SONET and SDH. Another problem of traditional FDM or Subcarrier Multiplexing (SCM) ─ being analog ─ is its susceptibility to accumulated waveform distortion and crosstalk. For these reasons FDM is not competitive in today’s transport networks. Digital signal processing continues to reach new record high rates, thus enabling Digital Subcarrier Crossconnects (DSXCs) to operate even at the high transmission rates of optical signals. In DSXC, the incoming subcarriers are switched to the outgoing subcarriers by a controlled Radio Frequency (RF) crossbar switch. The power consumption required to switch subcarriers in and out is estimated to be only a fraction of the power dissipated by current TDM and packet switching based transport network solutions. Multiple DSXCs can be combined to design Digital Subcarrier Optical Networks (DSONs) [1], which are a promising energy efficient alternative to current electronic-based transport network techniques, e.g., OTN/SONET/SDH/MPLS-TP. The DSXC’s basic functionalities and modules are introduced and discussed in this paper.Item Digital subcarrier optical networks (DSONs)(The University of Texas at Dallas, 2013-06-18) Huang, Wanjun, 1978-; Razo, Miguel; Tacca, Marco, 1973-; Fumagalli, Andrea; Hui, Rongqing; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.Energy efficient networks are increasingly becoming a desirable feature in today’s market. Both the number of users and the average amount of data traffic generated by each user continue to grow, requiring more powerful network routers and switches, which in turn dissipate large amount of electric power to operate. This problem is in part circumvented by deploying all-optical wavelength division multiplexing (WDM) solutions in the network, which eliminate any electronic processing of the in-transit data at the intermediate network nodes by dedicating a path of light (a wavelength) across the network to directly interconnect two edge nodes. However, the all-optical approach is only suitable when the average quantity of traffic to be exchanged by two edge nodes is sufficient large to warrant one entire (or many) dedicated wavelength(s). Considering that optical transmission rates are moving up from today’s 10 Gbps to 40, 100 and even 160 Gbps per wavelength, the fraction of edge nodes that exchange such amount of traffic is not (surprisingly) limited, as many of the edge node pairs would require only sub-wavelength connectivity. Sub-wavelength connectivity is today offered by either Optical Transport Network (OTN) or Multi Protocol Label Switching with Transport Profile (MPLS-TP). These solutions run on top of the WDM layer. Unfortunately, the amount of required electronic processing in these solutions is such that an order of magnitude higher power consumption results compared to all-optical networks. Part of this extra power consumption is due to the electronic buffering of the in-transit data at the intermediate nodes. This paper points to an alternative solution to achieving sub-wavelength bandwidth assignment to edge node pairs, which eliminates the need for data buffering at the intermediate nodes. Sub-wavelength channels or circuits are creating by using spectrally efficient orthogonal frequencies in each wavelength, with each frequency arrying a fraction of the wavelength bandwidth. By assigning one or more such frequencies to one edge node pair, an end-to-end sub-wavelength circuit is created. At the intermediate nodes, incoming frequencies are switched to outgoing frequencies via specially designed frequency selective switches or cross-connects. The power consumption required to switch frequencies in and out is estimated to be only a fraction of the power dissipated by current transport solutions, thus mitigating the energy consumption struggle when assigning subwavelength capacities to edge nodes.Item High-speed self-configuring networks based on cost-effective plug-and-play optical (PPO) nodes(The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrae; Hui, Rongqing; Maloberti, F. (Franco); Gregori, Stefano; Cerutti, Isabella, 1973-; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.This proposal visualizes a future ad-hoc multi-gigabit network infrastructure connecting a very large number of inexpensive optical nodes. Such nodes will look like today’s Fast Ethernet switches, providing however, 2-3 orders of magnitude higher bandwidth, and larger geographical network coverage. Users will connect nodes using already installed fibers by a simple plug-and-play operation. Once connected, the Plug-and-Play Optical (PPO) nodes will continuously communicate with other nodes for a self-configuration of both network and nodes. An on-board optical micro-lab, advanced transmission models and an intensive signal processing are the key components to build a system that is able to intelligently adjust optical data flows and wavelength selection. The PPO node configuration will account for varying traffic patterns and changing conditions of the optical physical layer, e.g., introduction and removal of PPO nodes, aging of optical components, temperature changes, soft failure of network elements. The objective of this proposal is to identify the required technologies, to study protocols and algorithms, to develop suitable transmission models, to design and fabricate critical parts of an integrated optical micro-lab that will make the envisioned scenario a reality, and to amalgamate all the achieved results for proving the PPO node concept feasibility.Item Plug and play optical (PPO) nodes: network functionalities and built-in fiber characterization techniques(The University of Texas at Dallas, 2007-05-07) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Hui, Rongqing; Monti, Paolo, 1973-; Paradisi, Alberto; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength routing decisions based on the collected data. This paper discusses what are the open challenges that must be overcome to provide cost effective and performing ad hoc networking solutions based on PPO nodes. Three possible PPO node hardware architectures trading off complexity, cost and functionalities are presented along with their built-in fiber characterization techniques.Item Plug-and-play optical node architectures and their built-in optical fiber characterization techniques(The University of Texas at Dallas, 2013-06-18) Hui, Rongqing; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science.; University of Kansas. Department of Electrical Engineering and Computer Science.Cost-effective plug-and-play optical (PPO) nodes may enable a new generation of self-configuring and simple-to-deploy optical networks. Three possible PPO node architectures are discussed in the paper along with their built-in opitcal fiber characterization techniques.