The Tech Behind: “WiFi on Air” at 30,000 feet!

klm-wifi-logo-largeIt’s fascinating to see that many airlines in United States are offering “WiFi on Air” packages to the passengers. Most of the passengers are happily paying for such packages, maybe not as much for actual utility, as for the delight of texting their friends – “Guess where I’m texting from?!” The technology is still in the nascent stage, where you can complain about it being expensive and yet too slow. However, it is undoubtedly a big leap in technology. Let’s see how all of this works out for us at over 30,000 ft!

There are primarily two ways in which a WiFi communication network can be established within the high-flying airplanes.

Air To Ground Based Link: The first one is Air to Ground based, where an antenna is attached to the bottom of the plane to transmit and receive signals from ground based towers. The working is pretty much the same as cellular connections, however the operating frequency is 3GHz. The signal is transmitted from the plane to the nearest ground tower, which in turn relays the signal to the ground station. The ground station transmits the data to the ground tower which in turn relays the signal to the plane. There are almost 200 ground towers in USA that are dedicated to establish this communication network and more and more are coming up. The bandwidth for data is not that great, at 3.2 Mbps, that too not for each customer but for the entire plane! So limit yourselves to texting without any Voice over IP and video streaming applications. Such a communication system can be made more effective by using directional antennas on the plane for a more focused capturing of beam and thus, enhancing the bandwidth to 9.8 Mbps. It is but obvious, that such a system will cry out loud when the plane is flying over water bodies, as there will be no nearest tower to relay the signal to/from!

Satellite Based Link: The second one is Satellite Based network, where an antenna is attached to the top of the plane to transmit and receive the signals to the ground stations via satellites. The plane sends a request for data to the satellites, which communicates the same to the ground station. The ground stations sends the data for the requested web page to the satellite, which in turn relays the same to the plane. In this kind of a communication link we can achieve data rates from 10-30 Mbps. The operating frequency is in the Ku Band i.e. 12-18GHz. The satellites can take care of communication over Atlantic and Pacific ocean too!

It will be intriguing to see how this technology morphs into a more sophisticated form with higher data rates, more connectivity and availability at cheaper cost, in the coming time. The fear of hacking into the plane system is minimal with the differentiation of the operating frequency bands, however, the risk of opening up more an more communication links can’t be denied.


WiFi graduates to LiFi – Now internet from LED bulbs!

unnamed.jpgSurf internet, stream videos and make calls simply from a torch or the street lights or the headlights of your car. When Prof Harald Haas gave his first talk about this concept at TED, I was both fascinated and amused after watching it. But, honestly, I could never see that happening in the very near future. Blame my short-sighted vision or appreciate Prof Hass’s blazing fast progress, the first product is ready and out there in the world. It’s called Li-1st. Before telling you more about the product, let me talk about the science behind the concept.

LiFi is a term coined by Prof Harold, in line with conventional term WiFi. Both LiFi and WiFi are effectively used in communicating data using the electromagnetic waves, with the only difference that WiFi uses Radio Frequency while LiFi uses the visible light spectrum. If you compare the two spectrums, Visible light spectrum is almost 10,000 times broader than Radio frequency, meaning greater data transfer capacity. The basic idea of binary data in digital communication is still intact, however, instead of transmitting 1’s and 0’s, we switch the LED bulbs on and off in extremely small time gaps [almost 1000th of a nano second].The protocol used is more or less 802.11 [same as WiFi], with Manchester encoding followed with on off keying and pulse position modulation, in the physical layer of the protocol. The bottleneck of line of sight communication is both boon and bane. Opaque objects will definitely jam the LiFi communication, however, the protocols can be designed robustly using the concept of Orthogonal frequency division multiplexing [OFDM]. With this type of modulation, we can rather benefit from multi-path and direct communication is no more a necessity. Also, the fact that this type of communication is more suited to short-range communication, makes it lesser prone to being hacked. A small chipset with protocol implemented and connect to a light source is all that it takes to get this set up ready. It’s low-cost and capable of 250 times faster data rates than the best broadband currently available through WiFi.

Let’s talk about the first LiFi product. The father of LiFi, Prof Hass, founded the company PureLiFi [earlier known as PureVLC], which focuses specifically on visible light communication. Their first product is a bidirectional visible light communication device which is capable of uplink and downlink speed of 5 Mbps. There are two parts in the set up; first part is a transceiver unit which is connected to an LED light source and the other part is a similar transceiver connected to another light source and also connected to the laptop though USB. You can use this set up with the two light sources separated over a range of 3m for the above mentioned data rate. The light sources can be dimmed down without affecting the quality of video streaming much, so that the flash is not a disturbing factor. The product is still in the prototype phase and has also been demonstrated at a few conferences.

The applications of this concept are restricted only by the limits of our imagination. Imagine the reading lights on your top in the airplanes being a source of internet. Imagine the headlights in your cars being a source for navigation information, traffic control and accident prevention. Imagine beaming torches at one another to communicate.

LiFi is not supposed to replace WiFi by any means. Long distance communication is still made easy only through wireless networks, generally with RF and Microwaves. However, LiFi is simply an efficient add on to the existing infrastructure of illuminating sources around us.

An insight on 4G Technology


Today, I used the 4G Airtel Data Card for the first time, while sitting at the Bangalore Airport. 3G technology has been around for 10 years, believe it or not, and it’s high time for the next mobile telecommunication technology to seep in. 4G, short for Fourth Generation, is creating the buzz around the world as the successor. Apart from the usual voice and message services offered by 3G, 4G offers mobile ultra-broadband internet access to laptops, smartphones, tablets and other mobile devices. Simply put, it can give you the same or greater data speeds as home or office Wi-Fi when you’re in a taxi. In hotels and airports, it’s often faster than public Wi-Fi networks.

Who decides the 4G Standard? In March 2008, the International Telecommunications Union-Radio communications sector (ITU-R) specified a set of requirements for 4G standards, named the International Mobile Telecommunications Advanced (IMT-Advanced) specification, setting peak speed requirements for 4G service at 100 megabits per second (Mbit/s) for high mobility communication (such as from trains and cars) and 1 gigabit per second (Gbit/s) for low mobility communication (such as pedestrians and stationary users). Currently there are two potential candidates who are contenders for complying to the 4G standard defined by ITU. These are LTE and WiMAX.

4G vs 3G? The spread spectrum radio technology used in 3G systems, is abandoned in all 4G candidate systems and replaced by OFDMA multi-carrier transmission and other frequency-domain equalization (FDE) schemes, making it possible to transfer very high bit rates despite extensive multi-path radio propagation (echoes). The peak bit rate is further improved by smart antenna arrays for multiple-input multiple-output (MIMO) communications.

Your area has no 4G Network? In that case, you may fall back to a 3G network. On some services, you fall back to HSPA+, which is a slower 4G network, but still faster than 3G. airtel 4G LTE is currently only available in Kolkata, Bengaluru, Pune & Chandigarh, and will be coming soon to many more cities. Reliance Jio Infocomm will utilize RCOM’s nationwide intra-city fiber network for accelerated roll-out of 4g services in India.

Compatibility of your phone with 4G?  There can be signification issues on 3G network to upgrade to 4G as many of them were not built on forward compatibility.Mobile WiMAX Release 2 (also known as WirelessMAN-Advanced or IEEE 802.16m’) and LTE Advanced (LTE-A) are IMT-Advanced compliant backwards compatible versions of the above two systems, standardized during the spring 2011 and promising speeds in the order of 1 Gbit/s.

What to expect from 4G? Like other 4G LTE service providers, Airtel will give you a speed of around 5Mbps to 15Mbps. This speed is good for those who wants to download huge games from web, upload HD quality videos or even stream them on bigger screens. People also get 2Mbps of download speed on 4G network , so don’t get super excited after purchasing a 4G network. 

What’s Next? 5G! Expected to be introduced in the early 2020s.

Switch to 4G!!