MDPI - Publisher of Open Access Journals

12 pages, 4228 KiB

Open AccessCommunication

Operating Characteristic Curves of Optical Packet-Switching Using Optical Code-Division Multiplexing for Label Switching

by Kai-Sheng Chen and Chung-Lien Pan

Photonics 2023, 10(6), 613; https://doi.org/10.3390/photonics10060613 - 25 May 2023

Cited by 1 | Viewed by 1582

Abstract

In this paper, the operating characteristic curves (OCCs) of optical code-division multiplexing (OCDM) technology for label switching of an optical packet-switching (OPS) network was evaluated. A node structure for processing the packets, with spectral-amplitude-coding (SAC) labels, considering a balanced detector and an optical switch, was developed and modeled. The effects of decoding noises on the performance of both M-sequence and stuffed quadratic congruence (SQC) labeling systems were addressed. Hypothesis testing was applied to the decoder to investigate the results of label recognition. The null and alternative hypotheses were, respectively, defined as a decoder receiving the matching and mismatching labels. Due to the noise effects, the decoder output may not reflect the label status correctly. Type I error occurs when the null hypothesis is true while accepting the alternative one. Type II error occurs when the alternative hypothesis is true while accepting the null one. Analytic equations of both errors were given, considering a desired packet that was missed and an undesired packet shown in a switched path. The trade-off between these two errors, regarding the decoder threshold, was demonstrated in operating characteristic curves (OCCs). A better OCC could be found when a packet had more labeled payload bits, or when the utilized label code had a lower auto-to-cross-correlation ratio. Full article

(This article belongs to the Section Optical Communication and Network)

► Show Figures

Figure 1

15 pages, 2217 KiB

Open AccessArticle

Architecture and Performance Evaluation of a Novel Optical Packet Switch with Input Concentrators

by Hongzhen Yang, Xiuwei Mao, Zilu Fang, Wanke Chen, Ting Wang, Shuna Yang, Yuhu Zhao and Hao Chi

Photonics 2021, 8(11), 510; https://doi.org/10.3390/photonics8110510 - 12 Nov 2021

Cited by 3 | Viewed by 1968

Abstract

In this paper, we propose a novel optical packet switch (OPS) architecture with input concentrators, which employ multi-input single-output optical buffers to aggregate all the incoming traffic into a small size switching fabric. Accordingly, the physical size, the number of the needed wavelength converters, and the economic cost of the total OPS node are decreased dramatically. However, the deployment of input concentrators introduces additional packet loss and delay, except from the contention at the switch output. A Markov model is presented to study the packet loss ratio (PLR) and average packet delay given by the input concentrators. The corresponding closed form expressions are given. The model also demonstrates that the system performance can be greatly improved by increasing the buffer size when the traffic load is not larger than 0.69315. The analytical values are compared with the simulation results. All the obtained results show that the proposed model provides satisfactory approximations under different network scenarios. Moreover, the economic cost savings of the proposed OPS node at the present time and its evolution as a function of time are also discussed in detail. The proposed architecture can also be applied in a packet enhanced optical transport network (OTN). Full article

(This article belongs to the Section Optical Communication and Network)

► Show Figures

Figure 1

10 pages, 2443 KiB

Open AccessLetter

Two-Code Keying and Code Conversion for Optical Buffer Design in Optical Packet Switching Networks

by Kai-Sheng Chen, Chien-Sheng Chen and Xiao-Lu Wu

Electronics 2019, 8(10), 1117; https://doi.org/10.3390/electronics8101117 - 3 Oct 2019

Cited by 5 | Viewed by 2535

Abstract

Buffering management is a crucial function in current optical packet switching (OPS) networks. To avoid packet blocking due to competition for the same switched path, optical buffering is required to queue packets after a router makes the forwarding decision. In this paper, the author proposed a buffering scheme based on optical code-division multiple access (OCDMA), where each packet is encoded with an optical signature code. An optical coding technique combining spectral-amplitude coding (SAC) and two-code keying (TCK) is introduced to advance the buffering performance regarding packet loss probability. In TCK, the payload bits “1” and “0” of a stored packet are respectively converted to a SAC signal and its complementarity. As the Hamming distance between the coding signals of bits “1” and “0” is extended, the existing drawback that the OCDMA-based buffer capacity is limited by the decoder noise increased with the number of queued SAC packets is resolved. Moreover, an encoder consisting of a fiber Bragg grating (FBG) array is applied for simplifying the system design. A SAC signal and its complementary counterpart can be generated simultaneously without the need of an extra encoder. Full article

(This article belongs to the Special Issue Optical Communications and Networks)

► Show Figures

Figure 1

12 pages, 3256 KiB

Open AccessArticle

Multiple-Code Technique for Multi-Rate Transmissions in Optical Packet Switching Networks Based on OCDMA Labels

by Kai-Sheng Chen

Photonics 2019, 6(2), 60; https://doi.org/10.3390/photonics6020060 - 30 May 2019

Cited by 3 | Viewed by 3543

Abstract

Supporting multi-rate transmission is an essential factor in current optical packet switching (OPS) networks. In this paper, the author studied a multi-rate scheme capable of forwarding packets with different signal rates based on label switching. The multiple-code (MC) technique was employed to label a packet by conveying its payload bits to multiple optical code-division multiple-access (OCDMA) labels. Spectral-amplitude-coding (SAC), which represents the chips in an OCDMA code as a set of wavelengths, was introduced to remove the multiple-access interference (MAI) from the overlapping among labels. The author tested the system effectiveness by conducting numerical analysis to formulate bit-error probability (BEP) and spectral efficiency (SE). The simulation results showed that the proposed network had a stable BEP performance when switching the packet flows of multiple data-rates. Full article

► Show Figures

Figure 1

11 pages, 3919 KiB

Open AccessArticle

Label Stacking Scenarios in Hybrid Wavelength and Code-Switched GMPLS Networks

by Kai-Sheng Chen

Electronics 2018, 7(10), 251; https://doi.org/10.3390/electronics7100251 - 14 Oct 2018

Cited by 8 | Viewed by 3429

Abstract

Multi-protocol label switching (MPLS) is a promising solution to implement high-speed internet protocol (IP) networks by reducing the layer number. To meet the increasing demand for data traffic, optical packet switching (OPS) is integrated under IP to provide high bandwidth to end users. Generalized MPLS (GMPLS) is perfectly compatible with the routing algorithm in IP/MPLS as it supports packet-switching functions. In this paper, we investigate the label stacking scenarios in GMPLS networks. In GMPLS, label stacking is done to reduce the node complexity by appending multiple labels to a single packet. Wavelength-division multiplexing (WDM) and optical code-division multiplexing (OCDM) signals have been widely used as identifying labels. As the labels can be permutated among the wavelengths or code dimensions, the structure of a label stack can be varied. However, studies on the relationship between label stacking scenarios and network performance are limited. To investigate this issue, we propose three label stacking models: sequential code distribution; sequential wavelength distribution, and random label distribution. The simulation results show that the sequential wavelength assignment, wherein the labels are uniformly distributed among the wavelengths, exhibits the best system performance in terms of the label-error rate (LER). Full article

(This article belongs to the Special Issue Optical Communications and Networks)

► Show Figures

Figure 1

18 pages, 7427 KiB

Open AccessArticle

Ultra-High-Capacity Optical Packet Switching Networks with Coherent Polarization Division Multiplexing QPSK/16QAM Modulation Formats

by José Manuel Delgado Mendinueta, Satoshi Shinada, Hideaki Furukawa and Naoya Wada

Photonics 2017, 4(2), 27; https://doi.org/10.3390/photonics4020027 - 7 Apr 2017

Cited by 8 | Viewed by 8291

Abstract

Optical packet switching (OPS) networks and its subsystems, like the burst-mode receiver, are an essential technology currently used in passive optical networks (PONs). Moreover, OPS may play a fundamental role on future hybrid optical circuit switching (OCS)/OPS networks and datacenter networks. This paper focuses on two fundamental subsystems of packetized optical networks: the digital coherent burst-mode receiver and the electro-optical switch. We describe and experimentally characterize a novel digital coherent burst-mode receiver that makes uses of the Stokes parametrization to rapidly estimate the state of polarization (SOP) and optimize the equalizer convergence time. This burst-mode receiver is suitable for optical packetized networks that make use of advanced modulation formats such as quadrature amplitude modulation (QAM). We study the suitability of (Pb,La)(Zr,La)O₃ (PLZT) optical switches for amplitude-variable coherent polarization division multiplexing (PDM) 16QAM modulation format and demonstrate a switching capacity of 10.24 Tb/s/port. We demonstrate a full 2 × 2 OPS node with a control plane capable of solving packet contention by means of packet dropping or buffering with a switching capacity of 10.24 Tb/s/port. Finally, we demonstrate the operation of the 2 × 2 OPS node with a record capacity of 12.8 Tb/s/port plus 100 km of dispersion-compensated fiber transmission. Full article

(This article belongs to the Special Issue Optical Networks for Communications)

► Show Figures

Figure 1

Search Results (6)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (6)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI