共查询到10条相似文献,搜索用时 15 毫秒
1.
To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in an access Passive Optical
Network (PON), the use of a Reflective-ONU (R-ONU) is a good choice for up-data transmission. An optical carrier is sent by
the Optical Line Terminal (OLT) at the Central Office, and a device at the ONU modulates the carrier with the upstream data.
This allows all ONUs to be equal and colorless, without a light source in a Hybrid WDM/TDM architecture. A Dynamic Bandwidth
Allocation is placed at the OLT, managing the lasers and photodetectors shared by all R-ONUs. The OLT laser and photodetector
employed in an up-data transmission must be tuned for each ONU and a particular Round Trip Time (RTT), which is twice the
propagation time from OLT to ONU. When an R-ONU is served by a laser, the photodetector must also be available after the RTT
to demodulate the up-data. We propose a novel nesting ranging algorithm to deal with large different distances OLT–ONUs avoiding
collisions and minimizing the delay under Priority Queuing with Quality of Service (QoS).
相似文献
Josep SegarraEmail: |
2.
Flexible TDMA/WDMA passive optical network: Energy efficient next-generation optical access solution
Abhishek Dixit Bart Lannoo Goutam Das Didier Colle Mario Pickavet Piet Demeester 《Optical Switching and Networking》2013,10(4):491-506
Access networks must further advance to address the intensification of the requirements of growing speeds and the usage of Internet applications, and time and wavelength division multiple access (TDMA/WDMA) based passive optical networks (TWDM-PONs) have been widely considered as one of the evolutionary steps of next-generation optical access (NGOA) networks. TWDM-PON combines the flexibility of TDMA with an increased capacity offered by the use of a WDM layer. Moreover, it offers interesting and challenging avenues to minimize energy consumption: especially, with current access networks consuming about 80% of the energy consumed in the Internet. Along with other efforts, reducing energy consumption of central offices is conspicuous as it directly minimizes the operational expenditures of network providers. In this paper, we explore the new paradigms to conserve energy at the central offices in TWDM-PONs. By extensive simulations, we evaluate the possible energy savings in the various flavors of TWDM-PON. Based on the findings, we propose a new architectural flavor of TWDM-PON and benchmark the architecture for cost, power consumption and reach. We also propose a novel energy saving scheme for the proposed architecture and evaluate the impact of the proposed algorithm on energy savings by extensive simulations. 相似文献
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This paper presents a scalable and costeffective hybrid time division multiplexing (TDM)/wavelength division multiplexing (WDM) passive optical network (PON), in which reflective semiconductor optical amplifiers (RSOAs) are used as optical network units (ONUs) and a shared tunable laser and photoreceiver stack locate at the optical line terminal (OLT). Especially,tunable transmitters are not only shared by all ONUs, but also used for both upstream and downstream transmissions. To solve resource contention problem and provide and the ONUs, two novel algorithms are proposed to manipulate the wavelength accessibility and the burst scheduling. The performance of both algorithms in terms of the average packet end-to-end delay and throughput were simulated and evaluated. 相似文献
5.
Abdulgader A. Habiballa Fahad A. Al-Zahrani Ayman G. Fayoumi Anura P. Jayasumana 《Photonic Network Communications》2006,12(3):285-294
The effects of different wavelength conversion ranging configurations on the performance of Wavelength Division Multiplexing (WDM) optical switches are investigated. Any-to-Any, Any-to-Range, Range-to-Any, and Range-to-Range conversion ranging configurations are considered. These mechanisms provide important design alternatives for optical switches due to technological limitations in the implementation of full range wavelength conversion in an all-optical wavelength converter device. Limited-range wavelength converter (LRWC) is a more economical and practical solution for WDM based optical networks. Differences among the input and output side ranging mechanisms and their effects on conversion resource sharing, and consequently on performance, are investigated. Any- to-Range ranging configuration is the most efficient mechanism and it operates comparably to Any-to-Any, reducing the need for complex control algorithms. The results help determine the most efficient ranging configuration for all-optical crossconnect. 相似文献
6.
Edward Mutafungwa 《Photonic Network Communications》2007,13(1):53-66
Optical code-division multiplexing (OCDM) is a technique that is currently generating considerable research interest. This paper analyzes and compares the traffic performance of wavelength-division multiplexing (WDM) and hybrid OCDM/WDM-based optical networks. The analysis considers the influence of the limitations of fiber-induced signal impairments on traffic performance and comparisons are performed for an example network utilizing different standardized fiber types. Furthermore, comparisons of traffic performance are also made between different lightpath schemes used in WDM and OCDM/WDM networks. The analysis results show that the OCDM/WDM lightpath schemes significantly outperform the WDM lightpath schemes for given blocking probability criteria. Moreover, the analysis indicates that fiber nonlinearity (which limits the minimum channel spacing) affects the traffic performance more severely compared to fiber dispersion (limits code cardinality). 相似文献
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对卫星通信中比较常用的多址接入方式进行了比较,提出了一种固定分配与自由分配相结合的卫星混合多址接入协议,对指标性能进行了分析。试验结果表明,该协议具有业务接入灵活、卫星频带利用率高、系统实现简单等特点,适用于高动态平台卫星通信。研究内容对相关工程应用具有一定的参考价值。 相似文献
9.
对卫星通信中比较常用的多址接入方式进行了比较,提出了一种固定分配与自由分配相结合的卫星混合多址接入协议,对指标性能进行了分析。试验结果表明,该协议具有业务接入灵活、卫星频带利用率高、系统实现简单等特点,适用于高动态平台卫星通信。研究内容对相关工程应用具有一定的参考价值。 相似文献
10.
In this paper we examine the resource provisioning aspects in a passive optical network (PON) employing wavelength-division multiplexing (WDM) and optical code-division multiple access (OCDMA) techniques. A judicious resource allocation scheme is proposed for a given set of optical codes and wavelengths with due consideration to the traffic asymmetry between upstream and downstream transmissions. The proposed scheme employs some initial heuristic estimates, followed by a subsequent open search mode towards reaching an optimal solution. The search mechanism in the provisioning scheme is carried out by employing some network performance metrics and evaluated using the appropriate analytical models. 相似文献