V band and the policy dilemma

The radio spectrum in the 57-71 GHz (called as the V band and millimetre band) has some unique characteristics—it’s the subject of discussion amongst the Department of Telecommunications (DoT), Telecom Regulatory Authority of India (TRAI), the industry and academia for close to four years now. 

The high oxygen absorption in this band, especially in 57-64 GHz, mitigates interference and hence requires less active interference management. These characteristics direct the policy dilemma in V band, namely whether to license the band or make it licence-exempt. The Institute of Electrical and Electronics Engineers (IEEE) ratified IEEE 802.11ad wireless access systems in V band in 2013 (also called as WiGig), which allow devices to communicate wirelessly at multi-Gigabit speeds and deliver high-definition content over shorter distances.

More work is in progress on IEEE 802.11ay specification, the successor to 802.1ad, which increases the peak data rate to 100 Gigabit per second using the V band. This recent specification also enables the formation of wireless local loop systems as potential substitutes for deploying optic fibre cables to home. As is the case with the widely used Wi-Fi bands of 2.4 GHz and 5 GHz that have been globally unlicensed, most of the countries including the UK, the US, Australia, China and South Korea have unlicensed the V band as well.

In India, the National Frequency Allocation Plan (NFAP) 2011 considers only part of this globally harmonised band for possible deployment of high-capacity dense networks. Quoting the above, Trai recommended the release of 57-64 MHz band for high-capacity backhaul in 2014. Instead of the licence-exempt option, Trai recommended link-by-link fixed fee based mechanism (and not auction) for assigning the band to TSPs, as is prevalent for other microwave backhaul spectrum.

Due to various reasons—including the after-effects of the 2012 Supreme Court judgment on allocation of spectrum through auctions—it never saw the light of day. In 2015, however, Trai, though referring to its earlier recommendation, indicated that following other countries India should also de-licence the 60 GHz band immediately. Even after three years, these recommendations have not been acted upon by DoT.

Due to this abeyance, the backhaul spectrum has not been released for quite some time to TSPs, which is one of the main reasons for slow network speeds despite deploying state-of-the-art 4G LTE network by the operators. High-capacity backhaul, and adoption of the latest IEEE 802.11ad and IEEE 802.11ay standards for local access are both important for effective 5G deployment. Hence, it is in the interest of the users that DoT, Trai and the industry body come together for a viable solution regarding the critical band.

 we need high-capacity wireless backhaul, apart from other high-frequency bands such as E band, the upper portion of the V band (67-71 GHz) shall be considered for licensing for point-to-point backhaul. It is important to note that the centralised allocation of frequencies as is being practised by the Wireless Planning and Coordination Wing of DoT is inefficient and time-consuming. It’s time we develop a geolocation-based spectrum database for India, as is being done in other nations.

 V Sridhar Professor, IIIT Bangalore