1. Wide open spaces of Indian White Space spectrum

Wide open spaces of Indian White Space spectrum

There is hardly any White Space spectrum in Band IV in lower UHF in India. Instead, there is a vast expanse of ‘non-white’ spectrum—one could call it regular spectrum

By: | Updated: December 8, 2015 12:34 AM
So, what is this White Space spectrum? Simply explained, it refers to the small gaps or empty spaces unused in an otherwise heavily-occupied broadcasting spectrum band. In the current context, the reference is to the so-called Band IV in lower UHF—covering frequencies from 470 MHz to 590 MHz.

What is this White Space spectrum? Simply explained, it refers to the small gaps or empty spaces unused in an otherwise heavily-occupied broadcasting spectrum band. In the current context, the reference is to the so-called Band IV in lower UHF—covering frequencies from 470 MHz to 590 MHz.

These are interesting times in India, with talks of many novel concepts and propositions; for instance, there is much excitement about one of the intriguing proposals floating around that concerns the exploitation of the so-called White Space spectrum for providing affordable telephony to the rural unconnected. It is a very bold suggestion simply because it is predicated on the use of a spectrum resource called White Space spectrum, which is practically non-existent in the country.

So, what is this White Space spectrum? Simply explained, it refers to the small gaps or empty spaces unused in an otherwise heavily-occupied broadcasting spectrum band. In the current context, the reference is to the so-called Band IV in lower UHF—covering frequencies from 470 MHz to 590 MHz. This situation is applicable or relevant to the western and developed economies which have had multiple terrestrial broadcasters. In terrestrial broadcasting, one had to perforce leave a small gap of non-utilised spectrum between adjacent channels, which is essential to avoid interference.

In view of the fact that western countries have had several terrestrial broadcasters, there was a proliferation of such idle or unused small spaces which came to be called White Space spectrum. There has been much interest in the West for many years now to make profitable use of this spectrum for commercial communication. In fact, there have been several pilot trials but significant commercial operations have still not happened anywhere. In India, too, a few pilot trials are in progress and IIT Bombay has been doing much work in this field.

Considering Microsoft’s involvement and Satya Nadella’s announcement about connecting 5 lakh villages using White Space technologies—for which free unlicensed spectrum is being sought—the interest and curiosity have heightened considerably. However, several experts have raised serious concerns and posed tough questions about the tenability or relevance of the White Space spectrum plan for India. They point out that the proposal of White Space spectrum is not only completely inappropriate for India, but is also harmful to the interests of consumers and the nation for several cogent reasons.

First and foremost, as mentioned earlier, there is hardly any White Space spectrum in the concerned UHF band in India. Instead, there is a vast expanse of ‘non-white’ spectrum—one could even call it regular ‘black spectrum space’. This is because, unlike the developed economies, India has only a lone and solitary public terrestrial broadcaster, Doordarshan, in this band. Of its total of 1,415 transmitters, Doordarshan has only 373 operating in the UHF band and all the remaining work in two other VHF bands. Based on an extensive study carried out by IIT Bombay, it has been established that, at any particular location, 11 out of 15 channels are almost always available. They, therefore, concluded that, in the worst case, 70% of the spectrum band can be freed up by the simple reassignment of TV channel frequencies in India. This would mean that a staggering quantum of about 88 MHz of regular non-white spectrum is available for deployment. This is big. We don’t have anywhere near this in the core mobile bands of 800, 900, 1800 or 2100 MHz—in these, India has only about 50% of what is the global norm. Not only do we now have access to 88 MHz in UHF to help compensate for the tragic shortfall in the core bands, it should also be noted that this UHF spectrum is comparatively far more superior/powerful in its propagation characteristics. These radio waves can easily travel 20 km or more in rural areas and can also penetrate buildings to provide excellent in-building coverage in urban areas. Thus, this spectrum would be tremendously beneficial for use in advanced mobile services and mobile broadband, which are near-necessities for Digital India and for uplifting the economy.

On the other hand, the advocates of the usage of the mythical White Space wish to have it allocated free and deployed as unlicensed Wi-Fi access and also for middle mile. With all due respect to the eminent authorities involved, such a usage would be a highly retrograde step for India. Firstly, to achieve Wi-Fi access, the transmitters have to be of extremely low power of the order of milliwatts and this would be necessary to ensure that the radio waves do not travel far to avoid severe interference problems. This action would be quite bizarre, since with such low-power transmission, one would actually be ‘killing’ the prime prized property of excellent propagation characteristics of these radio waves, whereas we are actually starved of enough spectrum with this characteristic for meeting India’s connectivity needs.

In addition, TV White Space technology is being touted as a fibre extension or the “middle mile connectivity”. Based on field trial reports, it has been established that TV White Space provides 1 MBPS for every 1 MHz spectrum consumed. If the objective is to provide 100 MBPS at the gram panchayat level—which is the ‘national mandate’ of the NOFN or the Bharat Net Project—then TV White Space would need at least 100 MHz of unlicensed spectrum, which effectively means the entire UHF Band IV itself! Surely, this cannot be a spectrum efficient backhaul technology for providing rural broadband when there are other cost-effective millimetre wave technologies that provide higher capacities which require far less spectrum and that too in dedicated licensed bands.

Assigning the TV UHF Band IV for promoting non-conventional and proprietary technologies by assigning the entire band as unlicensed will lead to suboptimal usage of the band. Moreover, it would only fragment it, like the core bands which have been fragmented historically through unplanned and arbitrary assignments, thereby leading to problems of inefficiency which we are still struggling to correct.

In conclusion, the availability of a large quantum of the valuable TV UHF spectrum affords great opportunity for achieving the desired connectivity and reap huge socio-economic benefits, provided it is allocated through open and transparent action, and not frittered away as unlicensed White Space.

The author is honorary fellow, the Institution of Engineering & Technology (London), and a consultant. Views are personal

Tags: Spectrum
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