Of late, there has been a surge in data traffic and 5G is expected to further add to this. This increase in data usage has led to consumers demanding better speeds and quality experience on their networks. In order to address this demand, networks will need to be made more agile and capable. This can be achieved by deploying fibre, as it can provision services that require high speed, ultra-low latency and limitless bandwidth. Further, fiberisation can make the telecom network highly secure due to its sensor-driven disaggregated architecture.

Industry stakeholders are increasingly exploring means to increase fiberisation at the backhaul and across the last mile. Various trends such as the emergence of 5G, deployment of small cells and uptake of new age technologies such as AI, IoT and ML across enterprises further call for the need for fiberisation. Moreover, the recent surge in data consumption witnessed since the onset of the Covid-19 pandemic, leading to a shift in traffic patterns and bandwidth requirements, has made the case for increasing fibre penetration even stronger.

A look at the key trends dominating the fibre space, its demand drivers and the way forward…

Fiberising backhaul

Traditionally, the backhaul network of operators was dominated by microwave, which accounted for 75-80 per cent of the network. While microwave served as an adequate backhauling medium in the 2G era, in a higher quality 4G environment, microwave-based backhaul is becoming less relevant.

The introduction of 4G services has led to an increase in the uptake of high-bandwidth services and a surge in data traffic. In addition, 4G has enabled and given a boost to various digital initiatives of the government. All this calls for more advancements for backhauling the network, which can be done through fibre. Owing to the massive explosion in data, operators have started stepping up backhaul readiness by increasing fiberisation and rapidly expanding their transmission backbone and aggregation capacity. To this end, telcos have started revamping their backhaul networks to have a healthy microwave-fibre mix. This helps them  leverage fibre’s virtually unlimited capacity and extensive reach. While operators are currently deploying a combination of microwave and fibre at their network backhaul, going forward they will have to make their networks entirely fiberised. As telcos prepare to welcome 5G, creating massive OFC requirements across backhaul networks will be necessary.

Backhauling small cells

In addition to 5G, the deployment of small cells will call for more fiberised backhaul. Operators are increasingly deploying small cells across their sites to better manage the growing data traffic. There is a higher concentration of data traffic in urban areas, which cannot be met by macro cells alone. In fact, industry estimates indicate that in terms of the total cost of ownership, especially in urban areas, small cells are a more attractive option than macro cells as they render cost savings of about 40 per cent in site rentals, energy costs, etc. While small cells bring cost benefits, their efficacy is mainly dependent on the availability of a fibre connection. Small cell deployments often utilise the millimetre wave spectrum, relying heavily on fibre cabled connections for the backhaul portion of the network.

Thus, a fiberised backhaul is essential to support small cell deployment in urban areas as the use of microwave backhaul brings with it operational complexities and limits network performance. Moreover, increasing consumption of data indoors is compelling operators to step up their small cell deployments, which, in turn, is expected to create demand for more fibre backhaul.

Tower fiberisation

Given the current surge in data traffic, stakeholders in the telecom sector are increasingly realising the need to improve the capacity of the existing networks. While the current capacity per tower site is about 1 Gbps (for 2G/3G/4G services), once 5G kicks in the capacity needed for each site will increase to 10-20 Gbps. This also needs a fundamental change in the technology deployed at these tower sites. Traditional microwave can only provide speeds of 500 Mbps-1 Gbps and even

E-band microwave can provide only 1-2.5 Gbps of speed depending on the allocation of the number of spots. In order to achieve capacities of 10-20 Gbps, there is a need to deploy fibre across all the tower sites.

At present, India has around 0.5 million tower sites, of which only 0.1 million are fiberised, accounting for around 30 per cent of the total. This is significantly lower than global standards. In South Korea, 65-70 per cent of the sites have been fiberised while in the US, Japan and China, the level of fiberisation is 75-80 per cent. For the 4G network alone there is a need to fiberise 35-40 per cent of the tower sites. The need for tower fiberisation is becoming even more pertinent with the move towards technologies such as AI, IoT, ML and cloud.

Role of tower fiberisation in 5G era

As per industry reports, the site count for 5G networks will double from the current 0.5 million to around 1 million by 2022. The new sites will require network densification, including the deployment of small cells and increased fiberisation of tower sites. While fiberisation of towers had already been initiated during the 4G deployment phase, 5G would necessitate 100 per cent tower fiberisation.

Moreover, the deployment of large chunks of high frequency long term evolution (LTE) spectrum (such as 50 MHz+ on 2300 MHz, 2600 MHz bands) needs a fibre-based backhaul. Further, 5G requires each mobile site to backhaul multi-gigabit throughputs to the aggregation network, for which a robust fibre connectivity is a must.

In this scenario, operators need to step up their fibre-to-the-tower (FTTT) deployments to reap the benefits offered by 5G technology.

OFC in last mile

As India witnesses surging levels of data consumption, OFC is being seen as the most suitable medium for catering to this burgeoning demand. The need for significant OFC capacity in the last mile has only multiplied with the Covid-19 pandemic. Today, most of the data generation is happening inside buildings. The consumption of bandwidth-intensive applications such as high resolution videos is on the rise. But the kind of coverage and capacity available inside buildings is limited. Further, as fixed and mobile services are increasingly converging, the need to deliver fibre-to-the-home (FTTH) or fibre-to-anything (FTTx) is becoming even more important.

Highlighting the impact of Covid-19 on data surge, Girish Gupta, regional sales head, India, Sterlite Technologies, notes, “The traffic is becoming more symmetric in nature – we have as much upstream traffic being generated as downstream. We have seen a growth of 30-40 per cent in terms of data consumption for different operators in residential areas, where we have built last-mile networks. At the same time, this surge in demand has reiterated the inadequacy of last-mile infrastructure in the country. The ‘new normal’ has led to a point where the shift to digital is permanent and validated.”

Demand drivers

Among the various factors driving the demand for last-mile connectivity is the need to provide better speed and capacity to consumers. At present, 1G or more capacity per site is required to support the current volume and velocity of data traffic. Nearly 40 per cent of current sites need to be fiberised in order to sustain this kind of capacity.

Over and above this, the emergence of 5G will entail the provision of 10-20G kind of capacities per site along with ultra-low latency. In such a scenario, E-band and microwave solutions can serve as stopgap arrangements.

Another big driver of last-mile connectivity is the enterprise and business space. Efficient business operations require high speed internet services. As fixed and mobile services are increasingly converging, the need to deliver FTTH or FTTx is becoming even more crucial. At present, in terms of FTTH penetration, India has only 1.3 million FTTH households. China, meanwhile, has over 350 million FTTH households. Moreover, according to a recent report by ICRA, India’s per capita fibre coverage is around 0.09 km, which is way below that of its global counterparts. China’s per capita fibre coverage is 0.87 km while that of the US and Japan is more than 1.3 km.

Deployment models

Operators can adopt the traditional approach of building their respective last-mile networks but this model is laden with several inherent flaws, which will render it inefficient in the long run. Individual last-miles network will mean different last mile for different services. Further, it will create the problem of limited leasing and leasing based on some kind of barter. Leasing at times gets impacted due to business competition under such a model. All in all, it will result in limited utilisation of potential. Thus, if 60 per cent tower fiberisation is to be achieved by 2022, it is necessary that operators adopt a shared infrastructure approach. Towercos or independent companies can play an important role in building the last-mile network, which can then be leased out to operators on a non-discriminatory basis. This will result in overall efficiency in capex and opex due to multitenancy.

Active-Passive equipment in FTTx deployment

While fibre has emerged as a popular solution for addressing the ongoing data surge and to ensure last-mile connectivity, its widespread implementation does come with some constraints. One such constraint is the cost factor of laying fibre to the home. Running a dedicated and direct link all the way to each end user is quite expensive.

In order to address this challenge, the industry has started exploring different approaches to FTTx deployment. This includes active optical networks (AONs) and passive optical networks (PONs). These approaches are based on the principle of splitting the signal so that each fibre from the central office in the network’s core gets shared between multiple end-users. Also, in both cases, the split into individual fibres for each user happens fairly close to the customer.

The key difference between the two approaches is how the signal is split between the multiple fibres going to each customer. While AONs use active, electrically powered devices to direct the appropriate signal only to the relevant customer, a PONs use optical splitters, which require no electrical power, to send the signal to each customer. Further, while AONs entail the use of ethernet and a switching device to typically route signals to up to 500 customers, each switching cabinet within a PON can handle up to 128 end-users only.

According to HYC Co, an AON mainly uses a point-to-point (PtP) network architecture and each user can have a dedicated optical-fibre line. Under this network type, switching equipment such as routers and aggregators, active optical devices, etc. are deployed from the central office to the user distribution unit during the transmission of signals. These switching equipment are driven by electricity to manage signal distribution and direction signals for specific customers. Active optical devices include light sources (lasers), optical receivers, optical transceiver modules and optical amplifiers (fibre amplifiers and semiconductor optical amplifiers).

Meanwhile, a PON is a point-to-multipoint network structure and is believed to be the main technology to realise FTTB/ FTTH. A PON refers to ODN (optical distribution network) using only optical fibre and passive components, and only needs to use active equipment at the signal source and signal receiving end. In a PON, the optical splitter is the core, and the optical splitter is used to separate and collect optical the signal transmitted through the network. These splitters for PON are bidirectional. In the downstream direction, multiple services such as IP data, voice and video are distributed by the optical line terminal (OLT) located in the central office through broadcast and are distributed through the 1:N passive optical distributor in the ODN to all ONU units on the PON. Meanwhile, in the upstream direction, service information from each ONU is coupled to the same fibre through the 1:N passive optical combiner in the ODN without interference, and finally sent to the OLT at the central office for reception.

Future outlook

In recent times, there has been an unprecedented growth in data traffic. Covid-19-induced digital trends have further added to this data growth, thus underlining the importance of fixed broadband networks. Fibre is now being considered essential and an “absolute must” for supporting next-generation data-intensive networks. Going forward, as working from home becomes the new normal, we would need a lot more fixed broadband than we have ever wanted in the past. Moreover, as Indian enterprises adopt new technologies such as IoT, AI, ML, big data and blockchain, the consumption of data is only going to increase. In order to produce more data, a robust infrastructure will be required, which can be built using fibre.