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Passive Optical Network (PON) Structure with Dynamic Wavelength Allocation (DWA)

IP.com Disclosure Number: IPCOM000169373D
Original Publication Date: 2008-Apr-24
Included in the Prior Art Database: 2008-Apr-24
Document File: 6 page(s) / 149K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

Currently existing PON systems entail a number of limitations such as: - Limited bandwidth (1 Gbit/s effective channel capacity). - Limited evolutionary capability of the network deployment. - Complex network structure in case of supporting a very large customer base, requiring several separate PON branch deployments. - Limited system capacity extension options. - Limited capability for the downstream video broadcasting support. All types of PON networks, e.g. EPON (Ethernet PON), GPON (Gigabit PON), BPON (Broadband PON) as well as legacy ATM (Asynchronous Transfer Mode) based PONs (APON) show the above mentioned problems, mainly strictly limited bandwidth available for subscribers, scarce development potential as well as limited system upgrade options, resulting in the trend to increase the channel rate.

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Passive Optical Network (PON) Structure with Dynamic Wavelength Allocation (DWA)

Idea: Marek Hajduczenia, PT-Lisbon; Henrique Silva, PhD, PT-Coimbra; Paulo Monteiro, PhD, PT-

Lisbon

Currently existing PON systems entail a number of limitations such as:

- Limited bandwidth (1 Gbit/s effective channel capacity).

- Limited evolutionary capability of the network deployment.

- Complex network structure in case of supporting a very large customer base, requiring several separate PON branch deployments.

- Limited system capacity extension options.

- Limited capability for the downstream video broadcasting support.

All types of PON networks, e.g. EPON (Ethernet PON), GPON (Gigabit PON), BPON (Broadband PON) as well as legacy ATM (Asynchronous Transfer Mode) based PONs (APON) show the above mentioned problems, mainly strictly limited bandwidth available for subscribers, scarce development potential as well as limited system upgrade options, resulting in the trend to increase the channel rate.

Up to now, this problem has been solved by several system capacity upgrade options, e.g. by increasing the data rate, resulting in migration from 1 Gbit/s to transitory 2.5 Gbit/s and target 10 Gbit/s systems, as well as by increasing the number of available wavelengths while maintaining the same data rate per wavelength channel.

The following methods are known:

- System capacity upgrade for higher data rates by increasing the available bandwidth.

- System capacity upgrade by Wavelength Division Multiplexing (WDM).

- Mixed upgrade scenarios, e.g. capacity upgrade scenarios including both WDM overlay as well as raw data rate upgrade.

In the following, a flexible WDM PON architecture is proposed, basing on non-reciprocal passive PSC (Power Splitter/Combiner) modules realized by Y-junctions optimized in the coupling mode operation. As such, each ONU (Optical Network Unit) in the system receives all downstream transmission channels, and thus has to possess dynamic filtering capabilities. Additionally, low cost and multi- wavelength transmitters are required for the ONU side deployment to assure the capability of the particular unit to adjust its upstream transmission window to one designated by the central OLT (Optical Line Termination) controller. This way bandwidth shortage can be avoided through a DWA algorithm.

An ITU (International Telecommunication Union) CWDM (Coarse Wavelength Division Multiplexer) wavelength grid compatible PON network allows for both upstream and downstream transmission in a multi-wavelength environment, where the whole available wavelength set is divided equally between downstream and upstream channels. Since the ITU CWDM G.694.2 wavelength grid features in total 16 wavelengths allocated between 1271 and 1611 nm (center wavelengths given), eight wavelengths can be allocated for downstream transmission (1611,...