Browsing by Author "Yuang, Maria"

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A Virtual-Tree OFDMA PON System Architecture
(2012)
Yuang, Maria
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Tien, Po-Lung
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Chen, Jyehong
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Shih, Ju-Lin
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Hsu, Dar-Zu
OFDM PON has been considered to be one of the most prominent next-generation broadband wired access solutions. However, based on the current tree-architecture, existing OFDM PON systems face severe challenges when increasing the scalability and data-rate performance. In this paper, we propose a novel virtual-tree architecture of an OFDMA PON system (VTOPS). Coupled with the use of inexpensive direct modulation, VTOPS simultaneously achieves high reliability, scalability, and spectrum efficiency (i.e., high data rate) in a cost-effective manner. Theoretical and experimental results demonstrate that, by applying the pre-emphasis algorithm and subchannel adaptive modulation, VTOPS achieves 40-Gb/s downlink and uplink transmissions using low-cost 10-GHz directly modulated lasers.
An Energy and Cost Efficient WDM/OFDMA PON System Architecture
(2013-01-01)
Yuang, Maria
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Tien, Po-Lung
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Chen, Jyehong
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資訊工程學系
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Department of Computer Science
In this paper, we propose an energy and cost efficient WDM/OFDMA PON system architecture, referred to as NEWOPS. Based on a two-tiered semi-tree topology, NEWOPS allows a large number of ONUs to be connected to OLT using only a handful of colorless transceivers. NEWOPS\' unique architecture not only facilitates high spectral efficiency and flexible sub-channel bandwidth allocation, but also enables the system to achieve high energy and cost efficiency. We conduct a theoretical study to identify and resolve a new data-rate performance issue due to the colorless and wavelength re-use design of the system. Experimental results show that when only 5-GHz bandwidth is allotted for each wavelength, NEWOPS successfully achieves symmetric 20-Gb/s downstream and upstream OFDM-16QAM transmissions via the same fiber trunk. As a demonstration of our system, we show how NEWOPS achieves energy efficiency that is two to twelve times higher than that of a typical tree-based WDM/OFDM PON when supporting 40 ONUs.
Design and demonstration of a colorless WDM-OFDMA PON system architecture achieving symmetric 20-Gb/s transmissions with residual interference compensation
(2013-09-09)
Chen, Hsing-Yu
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Yuang, Maria
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Tien, Po-Lung
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Hsu, Dar-Zu
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Wei, Chia-Chien
In this paper, we propose a two-tiered colorless WDM-OFDMA PON system architecture that draws strengths from each individual WDM and OFDM PON systems. Specifically, the two-tiered architecture enables a colorless transceiver to be shared by a group of ONUs, resulting in drastic reduction of the system cost. For achieving colorlessness via reusing downstream light sources, we discover the residual power of downstream signal unexpectedly springs back after transmissions, causing severe interference to the upstream signal, and thus limiting the data rate of the upstream signal. We devise a method of adopting a common dispersion compensation module at OLT to reduce the residual power over all wavelengths. Experimental results show that, with an improvement of upstream signal's SNR up to 10dB, the system successfully achieves 20-Gb/s bidirectional OFDM-signal transmissions on the same wavelength over a 20-km SMF. (C) 2013 Optical Society of America
OPTUNS: Optical Edge Datacenter Network Architecture and Prototype Testbed for Supporting 5G
(2019-01-01)
Yuang, Maria
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Tien, Po-Lung
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Ruan, Wei-Zhang
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Lin, Tien-Chien
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Wen, Shao-Chun
We present the architecture/testbed of an SDN-based optical-tunnel-network system (OPTUNS) for 5G edge-datacenters. Benchmarking results show that, compared to electrical-spine-leaf datacenter-network, OPTUNS achieves 82.6% power saving and significantly lower mean/p99 latency under high traffic load/locality.
OPTUNS: Optical intra-data center network architecture and prototype testbed for a 5G edge cloud [Invited]
(2020-01-01)
Yuang, Maria
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Tien, Po-Lung
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Ruan, Wei-Zhang
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Lin, Tien-Chien
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Wen, Shao-Chun
An edge data center (EDC) network infrastructure is required to flexibly deliver massive bandwidth and ultralow latency for a 5G edge cloud. Existing electrical-switching-based infrastructure, however, has been shown incapable of meeting such requirements. In this paper, we present an EDC network architecture and prototype testbed, referred to as the intelligence-defined optical tunnel network system (OPTUNS). OPTUNS consists of a set of optical switching subsystems that operate collectively to facilitate packet transport through logical wavelength-based optical tunnels. These optical tunnels are governed by a software-defined-networking-based intelligent tunnel control system, in a proactive manner. As such, optical tunnels are always made available whenever needed. In essence, OPTUNS boasts several crucial features, including high scalability, massive wavelength reuse (yielding high bandwidth), proactive optical tunnel control (yielding ultralow latency), and fault tolerance. We have built an OPTUNS testbed, including 30 optical switching subsystem prototypes, that interconnect a total of 25 racks (400 servers). Benchmarking results show that OPTUNS achieves 82.6% power saving compared with electrical spine-leaf networks. Further, our NetPipe-based experimental results show that OPTUNS invariably achieves mean and p99 end-to-end latencies of less than 17 mu s, regardless of traffic load and locality. (C) 2019 Optical Society of America