The objective of PLANET is to define a cost effective full-service access network for the year 2000 supporting a large splitting factor (up to 2000) and covering a wide range (up to 100km). The access network needs to give subscribers access to both narrow band / broad band, and distributive / interactive services. The main rationale behind the development of such an access network is twofold. For the long term evolution of the core network, an extensive node consolidation is expected since switching cost decreases with the size of the switching site. In addition, due to the high number of users which can be connected to a single network, some significant gain in bandwidth can be achieved due to statistical multiplexing.
During the project a laboratory demonstrator and a small field trial will be realised.
PLANET is realising a wide range, high splitting PON-based access network which can offer narrow band and broad band services to residential and small business users at an economically viable cost in comparison with other potential technological solutions. In addition this access network will introduce a lower operational cost for the operator, by minimising the active equipment in the access network.
The demonstration of the technical feasibility and economical viability of a wide range access network should pave the way to a less hierarchical core network. This will enable further consolidation of current switching nodes, resulting in an overall cost reduction. Further, the PLANET concept should allow an easier integration of access networks into an All-Optical Network.
Main contributions to the programme objectives:
A cost effective full service access network based on PON technology, covering up to 100 km/2,000 subscribers
Contribution to the programme
A network to deliver multimedia services to large numbers of SMEs and domestic users at viable cost
The technical approach is as follows:
A general system study is being made which defines / specifies all aspects of the new access network. At first the PLANET parameters were validated. It was concluded that a range of 100km can result already in a significant switching node consolidation, and the proposed bandwidth capacity would allow to connect up to 15000 Living Units to the PLANET system. Further, a number of reference architectures of high splitting, wide range optical access networks are defined and are currently under evaluation. The study is based on the input it receives from technology studies on the required optical (e.g. E/O transceivers, optical amplifiers) and electrical components (burst mode analogue electronics, the TDM/TDMA digital electronics), and from computer simulations of the signal to noise ratio. For the evaluation special attention will be paid to the resilience of the access networks, and possible upgrading strategies will be studied.
A first evaluation of a laboratory demonstrator is being carried out. The demonstrator is based on the existing Alcatel APON system, with the downstream bitrate upgraded up to 2.5Gbit/s. A feeder Optical Repeater Unit (ORU) and splitter ORU have been realised in order to support bi-directional optical transmission over a wide range, high splitting PON in both the upstream and downstream directions. The ORUs are based on optical amplifiers. The optical amplifiers, used to support the burst mode signal in the upstream direction, are Semiconductor Optical Amplifiers (SOA). In order to prevent noise funnelling in the ORU splitter, which could be caused by the SOAs in the parallel branches, these SOAs are only switched on when a packet is actually passing through. Further, a high differential power-budget can be supported in the drop section by controlling also the gain of the SOAs.
An adapted TDM/TDMA transfer mode optimised for the long range and high splitting is defined, and the realisation of this has started. After testing developed building blocks on a laboratory demonstrator, the technology will be transferred to the field trial.
In parallel with this practical validation,, an economical evaluation of the proposed access network will be undertaken. An in-depth study of investment costs has already been made. Currently a Cost of Ownership study is underway.
Summary of Trial
A small field trial will be installed with a limited number of subscribers (10-20). The network shall cover a range of approx. 100km and support a splitting of 2000. The defined transport system operates at a bitrate 2.488Gbit/s downstream and 311.04Mbit/s upstream.
The access network which will be used for the field trial is located near Brussels- Belgium. It consists of a Passive Optical Network with a Fibre-To-The Building configuration.
network architecture: definition, introduction strategy, evolution path
definition of transport system
burst mode optical amplification.
high speed TDM/TDMA.
Funding SchemeCSC - Cost-sharing contracts