Home India 2007 Access networks in India

Access networks in India

by david.nunes
Sameer Dighe Issue: India 2007
Article no.: 6
Topic: Access networks in India
Author: Sameer Dighe
Title: Country Manager
Organisation: India, Sri Lanka, Nepal, Bhutan at Symmetricom Inc.
PDF size: 404KB

About author

Sameer Dighe is the Country Manager for India, Sri Lanka, Nepal, Bhutan at Symmetricom Inc. In the past, Mr Dighe worked with several major suppliers in the telecom test and measurement sector, including Subex Systems, Wandel & Goltermann and Acterna. In 2006, Mr Dighe received Symmetricom’s Platinum Award for his achievements. Mr Dighe holds a Bachelor’s degree in Electronics and a Diploma in Electronics and Telecommunications – both from Mumbai University, India.

Article abstract

Telecommunications have driven a sort of economic miracle in India by providing an infrastructure for business process outsourcing that takes advantage of India’s vast talent pool. India’s telecom infrastructure, both its core and access networks, are improving daily. Still, there are great differences in the availability and growth of access network between rural and urban India that the government is working to rectify. Hybrid, copper/fibre networks have proven to be the most cost-efficient solution to India’s voice and data needs.

Full Article

India is a vast country, geographically; it has long been known for the amazing variety, and diversity, of the local cultures and traditions one finds when moving from region to region. Similarly, the same sort of diversity can be found when examining the telecom scenario in each of India’s regions. The greatest differences in India, of course, are seen when comparing the country’s urban and rural regions. The current published teledensity of India is around 17%; the urban teledensity, however, far exceeds the rural teledensity. The telecom network, in general, is defined as a combination of the core network and the access Network. The core network is the backbone of any telecom network, while the access network, at times called the last mile, is that which connects the end user to the core network The access network is the one physically the closest to the end user. No matter how much flexibility and how many Gigabits/sec of capacity is introduced in the core network, only the right type of access network will bridge the gap between the end user and the operator and let the operator introduce advanced application programmes. The growth of India’s telecommunications from its independence to the 1990s was very slow. Since the early 1990s, however, there has been a tremendous growth in voice subscribers – way beyond anyone’s expectations – and the same sort of growth is now being seen on the data front The great number of new facility and service introductions – the 2.5G/3G network rollouts, the national Internet backbone, IPTV, FTTx, fibre to the ‘X’, to anything) and, recently, triple-play – is helping drive the growth of the telecom subscriber base. How, exactly, India’s access network has evolved to its current state and what sort of architecture will be needed to support the country’s growth in the coming years, is definitely worth thinking about. The past, the history of India’s telecommunications evolution, is fairly simple. In the past India’s access network was built of copper, copper and only copper. In the past, voice communication was the only sort that one needed to consider. Traditionally, copper pairs were the media used to connect between the local switches, the exchanges and the subscriber’s premises. Copper wiring provided a number of benefits: first and foremost, it could comfortably carry 3.4 KHz signals – voice telephony signals with attenuation – over several kilometres; second, it was, and still is, well suited to the adverse climatic conditions which dominate the length and breadth of India; and, third, the low cost of copper motivated its widespread use in the access network. The invention of fibre optics and the introduction of newer transmission technology made fibre cabling the standard for the core network. However, little if any fibre has been used in India’s access networks. Neither the initial cost of deploying the fibre access networks nor the cost of fibre maintenance could be justified given the limited budgets available. Presently, India’s urban access networks are largely a blend of fibre optic, using DSL, digital subscriber line, technology to deliver broadband service. In rural areas, however, the access networks are still dominated by copper. Recently, DSL technology has been used to increase the transmission capacity of copper pair networks by several orders of magnitude. The deployment of xDSL technology in the last mile network has helped to upgrade the capacity of India’s rural access networks considerably. There are certain limitations, however, that limit the applicability and expansion of this technology. The limits include bandwidth constraints, limits to the distance a signal can be transmitted between the exchange and the user, and comparatively higher signal losses. In the urban regions, fibre cabling extended between exchanges and to remote network nodes assures seamless broadband connectivity to any end user on the network regardless of the distance. Access networks in urban regions are typically deployed using a three level strategy. Level one uses SDH, Synchronous digital hierarchy, transmission technology to extend broadband capability to several kilometres from the main exchange. Level two involves the use of passive optical networks, PONs, which extend the fibre’s reach a kilometre or more towards the subscriber’s premises. Finally there is the xDSL network that can extend the broadband connectivity, using copper, four or more kilometres, depending on the specific technology employed. India has been successfully deploying this three level approach – a combination of fibre, PON and DSL – as a cost effective solution for urban broadband connectivity needs. How can we expect India’s access networks to develop in the coming years? The operators and service providers talk of adding a wide variety of interactive applications to the basket of services they offer; to do so they will have to build their access network capacity considerably. A number of possibilities are being considered to improve the capacity, reliability and flexibility of India’s access networks. The use of PONs is one of the better alternatives; it can provide the bandwidth for broadcasting and is suitable, as well, for interactive applications. With interactive TV, online gaming, e-libraries, e-learning, e-governance and other such applications rapidly gaining momentum, the use of PONs will be further explored to achieve multi-service delivery from the head-end directly to the customer premises. Instead of just bringing fibre to a neighbourhood hub (PON), some providers are considering fibre-to-the-curb, FTTC, to bring the signal from the head-end. Copper, xDSL technology would then be employed to extend broadband connectivity directly to the subscribers’ premises. This sort of access calls for a few more network elements, including the ONU, or optical network unit, which serves as the interface between a PON and the xDSL copper, and the network termination, NT, unit, which provides the power needed at the curb Pilot projects are now being conducted to test the feasibility of fibre-to-the-home, FTTH, in India. With FTTH, fibre is extended directly to the subscriber’s home. All-fibre access network solutions, such as FTTH, require special optical network termination, ONT, equipment; they offer much higher bandwidth capacity than the other solutions. Since the fibre goes directly to the home it costs much more to deploy so, at least until costs drop substantially, it will find limited use in India. The combination of copper cable and fibre optics in the access network complement each other; together they provide an economical way to extend the ability of the country’s access networks to provide broadband access. Since India’s overall teledensity is still quite low, compared to other regions of the world, the demand for connectivity is high. Most of India’s population resides in rural areas where the teledensity is, on average, much lower than that seen in India’s cities. The Indian government’s recent National Telecom Policy, in an effort to equalise the situation and improve rural connectivity, calls for building the rural access networks by providing one telephone line for every three houses in every village. Small digital exchanges designed to withstand the country’s rigorous climatic condition have already begun sprouting up throughout much of rural India. The spread of appropriate access networks and the existence of an ultra-modern core network have begun to have a significant impact on the Indian economy. India’s technical competence has long been recognised and appreciated globally. Since India had little telecom infrastructure to speak of, and few jobs in telecommunications, India’s technicians and engineers – avidly sought abroad – have for many years migrated to other countries where they could get high-paying jobs. Today, given the expansion of the telecommunications sector, the reverse is happening: Indian talent is returning and technicians from abroad are being called in to fill the gaps. India’s software sector – which was almost non-existent a decade ago – has grown explosively. By 1999 the software sector had already grown to a US$2 billion industry, and has been growing aggressively since. The existence of a modern telecommunications infrastructure has made possible the astonishing growth of India’s business process outsourcing industry, BPO, which depends upon call centres and telecommunications to provide a backbone for its operations. The expansion of India’s telecommunications networks is, similarly, stimulating applications such as e-learning, e-medicine, e-libraries, e-governance, IPTV and, most recently, applications. The convergence of telecommunications and information technology and the marketing of triple-play voice, video broadcasting and data services bundled into a single package, has had a tremendously successful start. Convergence has stimulated the country’s economy and created a great many important business opportunities. Telecommunications is bringing the dawn of a brighter day, and the growth of the access network is playing a critically important role in India’s success story.

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