Wireless fibre' is not a contradiction in terms. It is actually an apt description, chiefly of the spectrum in the E Band (71-76 GHz and 81-86 GHz) and also, to some extent, of the V Band (57-66 GHz). Unlike conventional microwave or MW spectrum, comprising frequencies in the range 4GHz to 40 GHz, these are high frequency waves with special properties. One unique characteristic is the ultra-high data carrying capacity of up to 2 gigabit per second of these radio waves.
With 3G in full flight and 4G also just taking off, India's data story has just begun. While the year-on-year growth in data has been in excess of 70 per cent in the last couple of years, it is generally accepted that the compound annual growth rate or CAGR will, as per GSMA (the apex mobile body of the world), be about 66 per cent for the next four or five years. This growth is being fuelled by the rise in adoption of smartphones from about 149 million units in 2014 to a projected 690 million in 2020. Again, mobile internet users will swell from 336 million in 2015 to 592 million in 2020 - even this is a penetration of 44 per cent only, and further high growth is inevitable.
Are our networks capable of coping with this data deluge satisfactorily? Irrespective of the ability of our access networks, the picture is clearly worrisome when one examines the critical requirement of 'backhauling' the data traffic from the access networks to the core networks. While 2G base stations needed up to 4 Mbps capacity only and 3G up to 30 Mbps, and these could be handled by conventional MW, the introduction of 4G makes it a completely different ball-game, with upwards of 120 or even 150 Mbps capacity required per base station.
Conventional MW cannot handle this large demand and, while fibre would be excellent in terms of capacity, it is not a feasible or cost-effective solution for the many short backhaul distances, especially due to the right of way issues involved. In urban and suburban environments like a Chandni Chowk or a Nehru Place or even a dense Gurgaon suburb, it becomes extremely challenging to bridge the last-mile gap between the fibre access point and the end-user building or complex. In many cases, the fibre reach is a couple of hundred feet short, or one has to go across a wide road or over buildings to reach the target customer premises.
It is then a herculean task to get the mandatory permissions to dig and lay fibre. One needs a new efficient and cost-effective technological solution and this is where the unique E Band millimetre wave solution (71-76 GHz paired with 81-86 GHz) appears as the Messiah. Its unique ability to cope with 1 to 2 Gbps data traffic, closely approaching a fibre-like capacity, while retaining the wireless advantage, makes it a great 'wireless fibre' solution. This technology can carry signals up to two to three km in urban areas without costly and time-consuming road-digging permissions or the high cost of fibre. Apart from such invaluable last-mile usage, E Band can also be very useful as a powerful redundant network to fibre in mission-critical data backhaul applications. Further, due to its narrow beam width, it has high potential for frequency reuse.
The E band is not a new untested solution. It is about eight to 10 years since major the US and UK adopted or permitted it. As of now, about 40 countries have licensed and/or allocated it. Significantly, E Band spectrum has been very effectively deployed in most countries that have good-to-excellent broadband penetration. Almost invariably, the 'light licensing' approach has been adopted by these countries, with something like a registration process only required. This appears to have worked well and India could consider adopting it.
It is well-known that in India, fixed broadband is many times costlier than the global norm. For the price-sensitive Indian market this is a serious deterrent for the take-up of broadband in our very low-penetrated markets. The wireless fibre, E Band, offers an 80 per cent reduction in per-Mb data backhaul cost. Though the capex cost is somewhat higher than traditional MW, the increase in capacity is an awesome ten times, thereby leading to a net 80 per cent reduction in per-Mb cost.
Like E Band, there is also a V Band, comprising 9 GHz of spectrum in the 57-66 GHz band, which also has very good data-carrying properties over smaller distances. This can also be leveraged for our data backhaul requirement from small cells of urban 4G networks and can be flexibly installed on street-level furniture. In many countries, V Band is treated by the regulator as a licence-exempt band. Trai has also recommended it for indoor licence-exempt applications and outdoor light licensed use. It could thus be a powerful enabler for progress in the areas of 4G, internet of things and smart cities.
Unlike WiFi, WiMax and other broad-coverage technologies whose system performance depends heavily on the radio and user environment, E band systems offer guaranteed data throughput performance, even under poor transmission conditions. They are not affected by fog, dust, air turbulence or any other atmospheric impairment that can disable optical links for hours.
The intrinsic advantages of E and V Band wireless fibre solutions are multiplied many-fold in the Indian scenario due to the high costs of fixed broadband adoption/usage, abysmally low broadband penetration and the enormous challenges in securing right of way permissions to lay fibre in the ground. E and V band wireless fibre solutions could just be the right catalysts for 'broadbanding' India expeditiously and realising our vision of Digital India.