It’s time we press the pedal on building high-capacity, low-latency networks
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 V band is suitable for short-range transmission, both for access as well as for backhaul that connects the tower antennas to the switching centres of mobile networks. Due to the high capacity available in this band, it can potentially provide Gigabit and higher speeds.
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.
These developments have prompted internet firms such as Facebook, Google to innovate around this very important band to offer a wide variety of solutions and hence lobby for licence exemption of the band. On the other hand, telecom service providers (TSPs) continue to lobby for licensing this precious band due its high capacity, and possible deployments for both access as well as backhaul.
In India, as much as 75-80% of the backhaul is on microwave due to lack of optic fibre deployment. Telcos need more spectrum for backhaul and it is in their interest to control this backhaul capacity. If unlicensed, then this critical element of the network can be leveraged by the unlicensed internet firms to provide bandwidth consuming content as a close substitute to telcos’ offerings.
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.
NFAP 2011 has to be amended to allow for the release of the entire 57-71 GHz for network deployment by TSPs and internet companies. Since the band 57-64 GHz causes minimal interference, the need for licensing it does not arise. Hence, this band shall be made licence-exempt so that both telecom and internet companies can use this band to provide Wi-Fi and wireless fibre access solutions at Gigabit speeds.
On the other hand, since 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.
This can enable light-touch regulation in some cases, with interference management done through registration and by the service providers themselves, instead of the archaic process being followed by WPC today.
It’s also time that we press the pedal on building high-capacity, low-latency networks. Spectrum is a precious resource and is perishable in nature. The regulatory and policy initiatives shall be swift to maximise the use of this precious resource for the welfare of the digital society at large.
The Author is Professor, IIIT Bangalore