Li-Fi (data via modulated light) Technology Development Difficulties

In summary, Li-Fi is a new form of data transmission that uses light to send and receive information. It is difficult to develop because of the line-of-sight problem, but a simple circuit can be created to send and receive data. Detection of the signal is difficult and a transceiver circuit might be required.
  • #1
taylaron
Gold Member
397
1
Greetings PFers
You’ve probably heard of the new “revolution” called Li-Fi (Light Fidelity) which is a method of data transmission utilizing the modulation of very high frequencies in LED light bulbs. A good demonstration (And probably the first) is here: http://www.ted.com/talks/harald_haas_wireless_data_from_every_light_bulb.html

I have a basic understanding of networking, Wifi, and electronic components. I’m having a difficult time understanding why it’s been so difficult to develop this technology (and I’m not simply referring to the line-of-sight problem). In my mind, a simple circuit can be developed to receive a binary signal and turn a specific solid state relay (one for each type of LED) on and off at a very high frequency. Modulation enabled = 1 bit, modulation disabled = 0 bit.

Am I correct when I assume the difficulty is in the software and not so much the hardware?

-Taylaron
 
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  • #2
Li-Fi seems to be the "next" method for sending and receiving high density data streams at high speeds. As for technical difficulties, none appeared in a quick search. What specific "difficulty" are you referring to?

An overview and description of various encoding methods on the Wiki page:
http://en.wikipedia.org/wiki/Li-Fi

and this:
UK researchers say they have achieved data transmission speeds of 10Gbit/s via "li-fi" - wireless internet connectivity using light. The researchers used a micro-LED light bulb to transmit 3.5Gbit/s via each of the three primary colours - red, green, blue - that make up white light.
http://www.bbc.co.uk/news/technology-24711935

As for detectors, see this for example:

Ultrafast transient responses of optical wireless communication detectors
The GaAs material response times are investigated experimentally and found to range from approximately 3 ps to 200 fs for 390 nm (violet) to 780 nm (red) photoexcitation.
http://www.opticsinfobase.org/ao/abstract.cfm?uri=ao-52-20-5042

and

“Ultrafast photodetector could lead to increased fiber optical broadband speeds”
Compared to a normal germanium photodetector, the avalanche design has enhanced the detected signal by a factor of 30. The gain-bandwidth product, which characterizes both the detector enhancement as well as operation speed, is as high as 310 gigahertz.
http://phys.org/news/2013-01-ultrafast-photodetector-fiber-optical-broadband.html#jCp
 
  • #3
And that is using "telegraph" technology.
 
  • #4
My difficulty is in understanding why this technology hasn't skyrocketed. Homes could be relatively easily retrofitted with adapters in the main breaker or sub breakers in the central breaker panel to modulate standard AC power. Devices equipped with simple recievers to detect even 1 color could transfer data at superior rates. All someone has to do is
1. design and build an adapter-transciever which integrates into a home's breaker panel and connects to the internet or network source
2. Find a suitable LED lightbulb capable of being switched on and off from it's main power and integrate a suitable photoelectric sensor. like this one: http://www.thenanoleaf.com/
3. Design and manufacture a circuit to process the incoming and outgoing data streams over the power lines and directly interface with each light bulb (like these: http://www.newegg.com/Product/Produ...E16833181121&gclid=CKuyv8K-u7oCFaF_QgodnQcAJg)

4. Develop a plugin for devices and equip them with a optical transciever identical to the one in the light bulb.

With decent resources and good engineers, I don't expect this to be a monumental challenge. Yet, progress seems stagnant. My difficulty is in understanding why*
 
  • #5
taylaron said:
Greetings PFers
You’ve probably heard of the new “revolution” called Li-Fi (Light Fidelity) which is a method of data transmission utilizing the modulation of very high frequencies in LED light bulbs. A good demonstration (And probably the first) is here: http://www.ted.com/talks/harald_haas_wireless_data_from_every_light_bulb.html

I have a basic understanding of networking, Wifi, and electronic components. I’m having a difficult time understanding why it’s been so difficult to develop this technology (and I’m not simply referring to the line-of-sight problem). In my mind, a simple circuit can be developed to receive a binary signal and turn a specific solid state relay (one for each type of LED) on and off at a very high frequency. Modulation enabled = 1 bit, modulation disabled = 0 bit.

Am I correct when I assume the difficulty is in the software and not so much the hardware?

-Taylaron
Hi, can you or someone educate me about how the LED receives & transmits data from/to say a smartphone? Is there a transceiver circuit embedded in a Li-Fi system? If a transceiver is required to enable a communication link then won't the Li-fi become redundant? I am sure that's not the case but I don't understand the basic transmitting & receiving part of function via a LED light. I know that data could be transferred through a very high frequency OOK modulation but am not sure how the LED bulb could receive the signal from say a smartphone or transmit data to a smartphone!

Please educate me-thanks
 
  • #6
WK Loo said:
but am not sure how the LED bulb could receive the signal from say a smartphone or transmit data to a smartphone!

well you need a transmitter and a receiver ... so the LED would be the transmitter at each end of the link. And you would need a photo-diode or photo-transistor as the receiver
 
  • #7
davenn said:
well you need a transmitter and a receiver ... so the LED would be the transmitter at each end of the link. And you would need a photo-diode or photo-transistor as the receiver
 
  • #8
well done ;) ... you quoted me but didn't respond ... did you understand what I was getting at ?

Dave
 
  • #9
Thank. Cost & performance wise, how'd you Li-Fi compared against, say Wi-Fi application? I wonder what Li-Fi would offer against Wi-Fi.
 
  • #10
davenn said:
well done ;) ... you quoted me but didn't respond ... did you understand what I was getting at ?

Dave
apology, Dave! Must had hit the wrong button when I did my 'reply' in the car!
 
  • #11
the LiFi would be considerably more secure than WiFi as its signal wouldn't penetrate walls to be picked up outside the building
and if the beamwidth was tight/narrow say from ceiling down into the users work cubical it would have good security even within the building

The interesting differences would come down to signal to noise ratios of either
say IR light is going to need lots of good narrow filtering to keep out ambient IR and visible light ... else there's going to be poor SNR
For 2.4 or 5.8 GHz RF WiFi easy to get excellent SNR

just some off the cuff general thoughts :)

Dave
 

Related to Li-Fi (data via modulated light) Technology Development Difficulties

1. What is Li-Fi technology and how does it work?

Li-Fi technology is a wireless communication technology that uses light waves to transmit data. It works by modulating the light from an LED light source at a very high speed, which can then be received by a photodetector and converted back into data.

2. What are the main difficulties in developing Li-Fi technology?

The main difficulties in developing Li-Fi technology include finding efficient and cost-effective ways to modulate the light, ensuring the stability and reliability of the data transmission, and overcoming interference from other light sources.

3. How does Li-Fi technology compare to Wi-Fi?

Li-Fi technology has several advantages over Wi-Fi, including faster data transmission speeds, greater security, and the ability to work in areas where Wi-Fi signals may not reach. However, it also has limitations such as shorter range and the need for a direct line of sight between the light source and receiver.

4. What are some potential applications of Li-Fi technology?

Li-Fi technology has many potential applications, including providing high-speed internet in areas where Wi-Fi is not available or feasible, in-flight entertainment systems, and secure communication in sensitive environments such as hospitals or military bases.

5. Is Li-Fi technology currently being used in any real-world applications?

While Li-Fi technology is still in the early stages of development, it is being used in some real-world applications such as in smart lighting systems, where it can simultaneously provide both lighting and data transmission. It is also being tested in various other applications such as in vehicles and underwater communication systems.

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