Need for speed: What telcos mean when they say 4G, LTE-A or VoLTE

Telcos trying to outdo each other with their announcements of faster networks is a welcome move


Almost all telcos claim they can provide speeds up to 21.1 Mbps on their 3G networks but real download speeds invariably fall when shared among users. Photo: Pradeep Gaur/Mint
Almost all telcos claim they can provide speeds up to 21.1 Mbps on their 3G networks but real download speeds invariably fall when shared among users. Photo: Pradeep Gaur/Mint

Call drops notwithstanding, it’s a given that no internet user would ever grudge the efforts of a telecom services provider trying to provide a faster network. Hence, telcos trying to outdo each other with their announcements of faster networks is a welcome move.

On 31 August, Bharti Airtel Ltd, India’s largest telecommunications services provider, said it has “deployed 4G Advanced technology (carrier aggregation across TD LTE and LTE FDD) in Mumbai”. This, Airtel claims, will result in a “superior 4G experience for Airtel customers through considerably faster data speeds and better coverage, indoors and outdoors”.

Telcos thrive on acronyms that most users little understand or even care about. Nevertheless, TDD LTE (also known as TD LTE) stands for Time Division Duplexing-Long Term Evolution. FDD LTE stands for Frequency-Division Duplexing LTE.

Both TDD and FDD differ in the way they treat data. Duplexing means a phone can transmit and receive simultaneously. TDD means the “receive” and “transmit” channels divide the time between them on the same frequency band. This means you can have more bandwidth available for either downloading or uploading.

FDD, on the other hand, uses a slightly different frequency for uploading and downloading. This does result in less possible interference and, hence, better reception. However, there are too many variables to decide which standard scores more when talking about faster downloads.

Airtel, on its part, launched its 4G services in Mumbai in May 2015 on the 2300 Mhz band using the TD LTE standard and recently added capacity on the 1800 Mhz band using FD LTE. Under carrier aggregation deployment, the capacities of TD LTE (2300 MHz spectrum band) and FD LTE (1800 MHz spectrum band) have been combined to enable better spectrum utilisation and efficiency. Carrier aggregation is used in LTE-Advanced in a bid to increase the bandwidth.

Vodafone India Ltd, meanwhile, is encouraging subscribers to “upgrade to Vodafone SuperNet 4G now to get faster speeds and a superior browsing experience”. The telco claims that its proprietary “SuperNet...not only boosts your upload and download speeds but also minimises your buffering time even while streaming HD videos”.

While no telco will state it openly, the clear driver for these announcements is the imminent launch of the Voice over LTE (VoLTE) commercial services by the telecom unit of Reliance Industries Ltd, Reliance Jio Infocomm Ltd, which is set to make the going tougher for existing operators such as Airtel, Vodafone and Idea Cellular Ltd. The mobile price wars, as reported in Mint on 30 August are another indication of the anticipated battle for cornering data users.

Also Read: Reliance Jio versus the rest: Round 4

Meanwhile, though, what does one make of Airtel’s “4G Advanced” technology, Vodafone’s “SuperNet” or RJio’s VoLTE for that matter?

The telecom world has seen a new mobile generation roughly every 10 years since the first 1G system was introduced in 1981. The first 2G system started to roll out in 1992, while the first 3G system first appeared in 2001. The 3G network is several times faster than the 2G one.

Almost all telcos claim they can provide speeds up to 21.1 Mbps on their 3G networks but real download speeds invariably fall when shared among users. Besides, most telcos have a so-called fair usage policy wherein speed drops after reaching a specified download limit.

In theory at least, 4G (which is a marketing term for LTE) should have data speeds capable of reaching 100-150 megabits per second while on the move, and 1GB per second when stationary. LTE Advanced (LTE-A) is supposed to be at least 3 times faster than standard 4G LTE speeds. Ericsson Inc. and Telstra Corp. Ltd, Australia’s largest telco, achieved a 1Gbps speed result over its LTE-A network in November 2015 “using a LTE-Advanced (five) Carrier Aggregation”.

VoLTE, as the name suggests, allows users to make voice calls over LTE. You may compare this to how you make voice calls over an instant messaging tool like WhatsApp.

Airtel claims its customers with mobile devices that support 4G Advanced will be able to enjoy 4G data speeds of over 100 Mbps—in effect, all those users with high-end smartphones.

In February, Airtel deployed India’s first carrier aggregation in Kerala and the network achieved 4G data speeds of up to 135 Mbps on commercially available mobile devices, the company said in its 31 August press release. This deployment (along with the Mumbai one) is a part of Airtel’s Project Leap, under which the telco plans to invest Rs.60,000 crore over the next three years to “meet the growing demand of voice and high speed data services in India and deliver the best network experience to its customers”.

In a 28 June report, Transparency Market Research (TMR) estimated the global LTE market to touch $610.71 billion by 2019 (it was $10.47 billion in 2012). Technology-wise, the market has been categorized into LTE Advanced (LTE-A), TD-LTE and LTE FDD. In 2012, the LTE-FDD segment led the overall market with a share of 56.8%, according to the TMR report. However, TMR predicts that the LTE Advanced segment will register the fastest growth in coming years.

So where does 5G fit in?

The buzz on fifth-generation, or 5G, technology is getting stronger. The speed of 5G is much faster than 4G—20 gigabits per second, fast enough to download HD movies in a span of seconds—and is expected to be the driver for trends such as the internet of things and initiatives such as smart cities and Digital India.

However, 5G networks are not expected to roll out until 2020 and the International Telecommunication Union is still working on 5G standards.

Also Read: Mobile price wars: Airwave auction set for flop show as debt pile on telcos

READ MORE