Harmonizing Sub 700 MHz Band

Background

In 2015, the WRC (World Radio Conference) took up for discussion the sub 700 MHz band (470-698 MHz) for possible deployment of IMT (International Mobile Telecommunication) services. Simultaneously, the Committee of Secretaries in India met and decided to support this band (470 - 698 MHz) for IMT services. The Idea was to capitalize on the opportunity (ongoing radio conference) to register our (India's) support for this resolution. However, by the time we were ready with all approvals, the process at WRC had matured and therefore, India's name could not get included in the footnotes (footnotes No. 5.295, 5.296A and 5.308A) along with the group of other like-minded countries. As we speak, these countries (at the regional and global level) are discussing various frequency bands (uplink and downlink combinations) to be used in this block (470 - 698 MHz). The purpose of this note is to layout the most efficient band plan for India in this band to reduce the cost of equipment and handsets and without sacrificing the need for spectrum for the government agencies.

Current Assignment

The NFAP (National Frequency Allocation Plan) allows the frequency block 470 - 698 MHz to be used for both Mobile and Broadcasting services (co-primary services). Fortunately, (unlike many other countries) India's only broadcaster (Doordarshan) has very little usage in this block of spectrum, as most of Doordarshan's analog transmitters are deployed in the frequency block of 174 - 216 MHz. However, there are other government agencies who are planning to use some portions of the sub 700 MHz band. The snapshot of assignment in this band is shown in the figure below.

To appreciate the density of usage of this spectrum band, I will like to point to a recent study done by IIT Mumbai. The study points out that more than 80% of the TV UHF band IV (470-585 MHz) is totally free and lying unused (see Table III of page 5 of the PDF in the link above). Hence sub 700 MHz band is mostly unused and therefore, can be easily harmonized (reconfigured) to support a more optimal band structure.  

Digitization of Broadcasting

It is worthwhile to note that Doordarshan's current analog assignment (174 - 216 MHz) is due for conversion to digital very soon. The new digital standards (DVB-T2) can pack up to 6 HD channels in one single block of 8 MHz. Also, using advanced interference management techniques, it is possible to configure the adjacent transmitters to the same frequency (Single frequency Network), thereby significantly increasing spectrum efficiency of broadcasting services. This will obviate the need for them (Doordarshan) to seek additional spectrum beyond Band IV (470-585 MHz). 

ITU-R & Sub-700 MHz Band

Working Party 5D of ITU-R, (responsible for defining the band structure for equipment), is deliberating on the following band plan for IMT. This band structure is expected to get finalized soon.

Recent Developments

In April 2017, US recently concluded a successful auction of this spectrum band, raising a total revenue $ 19 billion for the government. TMobile was the major bidder which has announced that it will roll out 5G services in this band by 2019. With TMobile targeting 2019 for roll out of 5G services, the device ecosystem for this band plan will not be that far.

Harmonization Proposal For India

Keeping in mind the actual usage of this sub-700 MHz band (470-698 MHz) and the frequency structure being discussed at the ITU-R Working Party 5D, following harmonized proposal can be considered by India.

470 to 617 MHz - Doordarshan + Government Agencies.

617 to 698 MHz - Commercial Usage (617-652 MHz paired with 663 to 698 MHz)

Note that 663 to 698 MHz is used as Uplink to prevent interference into the adjacent 700 MHz band (698 - 806 MHz).

Conclusion

Hence, it is clear that sufficient spectrum can be carved out in the sub 700 MHz band for deployment of IMT services in India, by optimally rearranging the assignments of Government and Doordarshan. Once that is accomplished, 2x35 MHz will be available for deployment of 5G in future. Globally, a lot of work around harmonization is happening on the above-discussed band structure in the spectrum block (617 - 698 MHz). In the interim, the Government agencies (including Doordarshan) can get accommodated within a larger block 470 - 617 MHz (65% of the total spectrum). Later, if required, this arrangement can be revisited, in case additional spectrum is needed. This will prepare India well in advance for rolling out 5G services in a lower spectrum band (< 1 GHz), thereby creating a win-win situation for all stakeholders.

(Views expressed are of my own and does not reflect that of my employer)