Optic fibre is the emerging capacity constraint
Reams have been written, and rightly so, on the havoc created—for both voice and data services—by the shortage of spectrum as well as towers, especially in high-traffic areas. This newspaper, for instance, has pointed out that in Delhi, a top telecom operator carries 49 hours of voice traffic every day per MHz per telecom tower as compared to 6.5 in Shanghai and 8.9 in Singapore—for data traffic, the comparable numbers are 3.4 GB, 0.2 GB and 2 GB respectively. And, as the number of consumers and their use of the internet rises, the situation will only get worse. Not much attention, however, has been paid to the emerging constraint of shortages of optic fibre—former Telecom Regulatory Authority of India (Trai) chief Rahul Khullar is one of the few to address this directly, in an article in The Indian Express a few weeks ago. The way to understand this is to understand how voice/data services are offered. Most consumers of the internet connect via mobile devices, be it phones or tablets. This is where the shortage of towers and spectrum come in. But what happens after the last-mile connection is established is important. After the data is aggregated at the tower, it needs to be transmitted via a switching centre.
This transmission—backhaul, in telecom jargon—can take place in two ways. Either through microwave towers or through optic fibre connecting all the towers. In cities like Shanghai and Singapore, most of the towers are connected through optic fibre. In India, however, the bulk of backhaul takes place through microwave spectrum. This, however, is where the problem is getting aggravated now. Each telecom tower today has equipment to transmit signals for different spectrum bands/frequencies—900 MHz, 1800 MHz, and 2100 MHz. For a normal tower in a city, there could be 25 Mbps of data being generated for 900 MHz, 30 Mbps for 1800 MHz and 65 Mbps for 2100 MHz. Given that most networks are designed in rings of 10 towers, that’s 2.4 Gbps of data that needs transmission to the switching system—this is something the microwave simply cannot handle efficiently. And now, with video likely to jump dramatically once 4G services proliferate, the amount of data being generated at each tower will increase dramatically. In such a situation, microwave backhaul will be completely insufficient. So, if the government wants Digital India to work, it has to ensure that the bulk of towers are connected through optic fibre. Doing so is not just an issue of capital with the telcos. The problem is that getting permission to dig up roads from municipal authorities is a nightmare, and that for each tower has to be taken separately—it doesn’t help that municipal authorities also over-charge for such permissions. The government will have to ensure such permissions are given as a matter of priority—‘right of way’, in telecom jargon, has to be made compulsory.