FSO: Enabling Connectivity in rural India
Free space optics (FSOTM) is a line of sight technology that currently enables optical transmission up to 2.5 Gbps of data, Voice and Video communications through the air, allowing optical connectivity without deploying fibre-optic cable or securing spectrum licenses. Such propagation of optical capacity through air requires light, which can be focused, by using light sources either light emitting diodes (LEDS) or lasers (light amplification by stimulated emission of radiation). The use of laser is a simple concept Similar to the one used in optical transmissions using fiber-optic cables; the only difference is the medium. Light travels through air faster than it does through glass, so it is fair tp classify FSO as optical communications at the speed of light.
FSO technology is relatively simple. it is based on connectively between FSO units, each consisting of an optical transceiver with a laser transmitter and a receiver with a Laser transmitter and a receiver to provide full duplex (bi-directional) capability. Each FSO unit uses a high-poer optical source (i.e. laser), plus a lens that transmits Light through the atmosphere to another lens receiving the information. The receiving
Lens connects to a high-sensitivity receiver via optical fiber. FSO technology requires no Spectrum licensing. Some FSO's open interface ability helps supporting equipment from a verity of vendors, which helps service providers to protect their investment in embedded telecommunications infrastructures.
FSO economics:
As the need for high speed connectivity grows, service providers are looking for reasonable priced, high bandwidth alternative to deliver service in shortest possible time without being inhibited by any water body or other obstacles which otherwise hinder deployment of reliable communication medium. In such an environment, FSO offers service providers a tool to generate revenue and provide enhanced service at a reasonable cost. FSO offers the following benefits;-
Quick customer acquisition:
FSO products are quickly and easily installed. This allows service providers to acquire target customers very quickly in comparison to fiber installs. Fast, easy upgrades allow service providers to retain customers as their bandwidth requirements increase.
· Increase network footprint:
FSO can be used to bring multiple off net buildings on net, thus incresing the reach of service providers at a fraction of the time and a reasonable cost.
· Access to new markets:
FSO products allow service providers to acquire target customers very quickly in comparison to fiber installs.
· Increase profit level on existing capital:
FSO allows service providers to extend their existing networks (fiber or LMDS) without the need for additional training, equipment, or licensing costs.
· Leverage existing capital budgets:
FSO products allow service providers to gain significant leverage in their capital by lowering. The cost of "wiring" buildings with high bandwidth access. This provides them an acceptable return on their capital investment on a lower rate of monthly telecommunications revenue.
· Complement to fibre:
With an increasing number of cities imposing trenching ordinances, exorbitant fees, and/or moratoriums, fibre deployeement is becoming more difficult, costly and time consuming. SO products eliminate the wait to acquire fibre facilities.
· Eliminate stranded capital:
The ease of installation and flexible reuse or redeployment off FSO products eliminates the risk stranded capital for fiber access to a particular building. When a customer vacates a building, the same FSO equipment can be moved and deployed to provide service to a customer in anther location, offering service providers a "zero-sunk” cost model.
FSO Applications:
FSO has several applications in metronetworks, where an optical gap exists between the network core and network edge. FSO delivers cost-effective optical connectivity and faster returns on investment (ROI) for enterprises and service providers. The number of FSO uses in metro networks and beyond continues to grow as high band-width demands and need for economically viable optical solutions outpace the deployment of fibre-optic cable.FSO has moved from niche to mainstream:
· Metro network extension:
FSO can be deployed to extend an existing metro ring or to connect new networks. These links generally do not reach the ultimate end user but are more an application for the core of the network.
· Enterprise:
The flexibility of FSO allows it to be deployed in many enterprise applications, such as LAN-to-LAN connectivity, Storage Area Networks, and intra-campus connections.
· Last-mile connectivity:
These are the links that reach the end user. They can be deployed in point-to-point, point-to-multipoint, ring or mesh connections.
· Fiber complement:
FSO may also be deployed as a redundant link to back up fiber. Most operators deploying fiber. Most operators deploying fiber for business applications connect two fibers to secure a reliable service plus back up in the event of outage.Insteade of deploying two fiber links, operators could opt to deploy an FSO system as the redundant link.
· Access:
FSO can also be deployed in access applications such as gigabit Ethernet acess.service providers can use FSO to provide high capacity link to business centers.
· Backhaul:
FSO can be used for backhaul, such as LMDS or cellular backhaul as well as gigabit Ethernet "off-net" to transport net work backhaul.
· Disaster management:
FSO can be used effectively deployed for disaster management. in the event of any fiber break FSO can be used to quickly restore the network.
· DWDM services:
With the integration of WDM and FSO systems, independent players aim to build their own fiber rings, yet they may own only part of the rings. Such a solution could save costly lease payment to ILECs, which are likely to take advantage of this situation.FSO is a line-of-sight optical technology in which voice, video and data are sent through the air on beams of light at speed up to 2.5 Gbps-more than 2,000 times the capacity of a traditional "high speed" connections such as DSL.FSO system acts the same way as a piece of fiber-optic cable. The current FSO product lineup of some companies provides band-width of 10, 20, 100, 155, and 622Mbps and 1.25 Gbps at 850 nm ane 2.5Gbps at 1550nm. FSO products are agile enough to integrate within any service provider network. Companies which manufacture products that work with Ethernet, Fast Ethernet, Gigabit Ethernet, SONET/SDH, ATM and FDDI obviously have wider acceptability. These products can be used for metro network extension, DWDM services, acess/last mile, wireless backhaul, disaster recovery, storage area net-works and LAN, as well as for WAN solutions.
The FSO deployement was slow on a large scale until late 2000 when it became clear that fiber optic cable would not reach into every building in the near future. The costs and challenges associated with trenching fiber in metropolitan areas can be prohibitive and band-width demands today in many cities are out stripping service providers’ ability to deploy fiber-optic cable. Combined with shrinking capital budgets, other gaps and applications in service providers network must also be addressed through viable alternatives such as FSO.
Globally, SO systems are being successfully used in USA, Mexico, Europe, China as also island countries like Indonesia, Philipinies, apart from India. Light pointe FSO system was very successfully used in New York after the September 11,2001,attack on World Trade Center to quickly rehabilitate wideband communication systems. Several Indian companies are also planning to deploy FSO. Tata Teleservices Ltd. has successfully evaluated Light Pointe FSO and they are progressively placing order for various types of systems for using in their networks. BSNL is in the process of trying out in the systems of Chennai. The preliminary evaluation has been successful. Reliance and Bharati rare carrying out paper evaluation of the systems. There are other government and non government establishments who have evinced keen interest in FSO systems and are in the process of evaluating the same; some are even acquiring limited numbers.
Acknowledgements:
Authors are thankful to Authorities of JITM, Paralakhemundi for providing a scope for presentation of paper and Prof. S.P. Panigrahi, Asst. Professor, IACR, Rayagada for sharing his knowledge and guidance.
