Solve : Li-Fi to replace Wi-Fi in China?

1.	Solve : Li-Fi to replace Wi-Fi in China?
Answer» Chinese scientists have successfully developed a new cheaper way of getting connected to internet by using signals sent through light bulbs instead of radio frequencies as in Wi-Fi, a move expected to radically change process of online connectivity. Full StoryNot really anything new as for IR was an ability to send print jobs between an old laptop I had an a printer many years ago. If they place the Transmit on one spectrum and Receive on another spectrum you can have full duplex communications without cross talk using filters at the receivers to only allow passage of a certain spectrum of light through which the photo transistors pick up on at the Access Point and the Computer. BUT the biggest issue with this LI-FI which was also the failure for IR was that you need a clear shot between the computer and the device communicating with the computer. BUT ALSO, the security risks of using LI-FI to me seems far less secure than WI-FI !!!, since a person miles away could have two telescopes ( 1 for each spectrum to pick up on the TX/RX ) pointed at your home with a receiver on each one with a filter for each spectrum, using basically an optical tap, and able to pick up the transmission, and RECORD it for later processing, or decipher it on the fly and be able to piece together the data contained in the strobed communication. To me a place like China would love for this ability to optically tap with no traces that the tap ever took place!Quote ... a place like China would love for this ability to optically tap with no traces that the tap ever took place!... What does that mean? From the article: Quote The term Li-Fi was coined by Harald Haas from the University of Edinburgh in the UK and refers to a type of visible light communication technology that delivers a networked, mobile, high-speed communication solution in a similar manner as Wi-Fi. Making any comparison with the now forgotten IR thing is not fair. The Chinese innovation can replace Wis-Fri in public areas. *Firefox spell check prefers Wis-Fri instead of the other spelling. I was told to spell check my posts, so don't blame me., talk to the Firefox people. Firefox does NOT suggest wis-fri...period. Now your inventing things...It is the Firefox spell checker.. Now, about in venting thins. Where does this idea that Light signals can not be traced? Then article is about using light for distribution over an area in place of using radio signals. The communication has to be INTER active. It has the same underlining technology as the Wi-Fi equipment. The reason fort using light, says the article, is to reduce costs. LEDs are super cheap. Certifiable 802.11 devices are not so cheap. To assume that the LEDs hide the identity of the recipient is pure pulp fiction. It has t o be two-way communication. It is called full duplex, if you need a label. Anyway, it is a real innovation, but not really a discovery. Using visible light means it will really be line-of-sight. Literally. Still, a one-watt LED can be very bright. Potentially a wide area could be covered by two or three transceivers. Perhaps a public library. An Airport, train station, rice paddy or fish market. Will it be useful here? Not if it is free. It's an interesting idea but I can't really see it being practical. I remember years ago my family had a Sony Handycam Hi-8 camcorder that could send the video to the TV via Infra-red light (With the help of a little receiver) - While this worked it was pretty unreliable e.g. if someone walked in front or the alignment got knocked off the picture would fail. And transferring data will be a lot more prone to issues like this compared to composite video from the old camcorder. I really can't see how this could be more practical than WiFi in any way - As soon as you move the machine between locations your link will LIKELY drop out. I can't see it being cheaper either as the price of mass-produced WiFi gear is so low nowadays. I don't really see an issue security wise though - The link would likely still be encrypted in some way so in that respect it would offer the same security as WiFi. Interesting to see that it came from the University of Edinburgh (Where I study) though - I hadn't seen anything about it. To me, this sounds like a 'research' type project to see what is possible.etc and has maybe been misinterpreted as to it being a technology that is about to come into the consumer market, while it is pretty amazing to see data at that speed transmitted over visible light without issues with interference, I can't see it taking over from RF communications - Mobile phones/PDAs moved from IR to Bluetooth and later WiFi for a reason!Quote Interesting to see that it came from the University of Edinburgh (Where I study) though - I hadn't seen anything about it. You should talk to your professers more...camerongray, your point is a valid argument. Until the real technical details are GIVEN, there is to easy way to know it is anything other that wishful thinking.rough. A quick search shows many 'experts' making commentates about this item as if nit was a real breath of fresh air in the the world of wireless. Yes, line-of-sight and moving objects are real limitation of super-high frequency communications. Here is an article NOT directly related. But it prides a background of what the issues are in sending a lot of data from one point to another. http://en.wikipedia.org/wiki/Advanced_Extremely_High_Frequency The article shows why the military have an interest in this form of radio communication. It also shows why line-of-sight is not the absolute limit. Now back to topic. It is not impossible for the researches to have made a real discovery. We already know that Gama radiation will penetrate objects like the human body. But the Chinese said it was visible light. Or did they? Are there discreet wavelengths that penetrate in the visible spectrum? Conventional wisdom says 'No, only X-rays do that, never visible light.' What abo0ut the professor from the UK? Here is a video of him earlier this year. http://www.nutshell-videos.ed.ac.uk/harald-haas-d-light/ IMO he is areal ENGINEER doing real research. He admits to the moving object issue. But pay attention his answer to the obvious question.

Answer»

Chinese scientists have successfully developed a new cheaper way of getting connected to internet by using signals sent through light bulbs instead of radio frequencies as in Wi-Fi, a move expected to radically change process of online connectivity.

Full StoryNot really anything new as for IR was an ability to send print jobs between an old laptop I had an a printer many years ago.

If they place the Transmit on one spectrum and Receive on another spectrum you can have full duplex communications without cross talk using filters at the receivers to only allow passage of a certain spectrum of light through which the photo transistors pick up on at the Access Point and the Computer.

BUT the biggest issue with this LI-FI which was also the failure for IR was that you need a clear shot between the computer and the device communicating with the computer.

BUT ALSO, the security risks of using LI-FI to me seems far less secure than WI-FI !!!, since a person miles away could have two telescopes ( 1 for each spectrum to pick up on the TX/RX ) pointed at your home with a receiver on each one with a filter for each spectrum, using basically an optical tap, and able to pick up the transmission, and RECORD it for later processing, or decipher it on the fly and be able to piece together the data contained in the strobed communication. *To me a place like China would love for this ability to optically tap with no traces that the tap ever took place!Quote

... a place like China would love for this ability to optically tap with no traces that the tap ever took place!...

What does that mean?

From the article:
Quote

The term Li-Fi was coined by Harald Haas from the University of Edinburgh in the UK and refers to a type of visible light communication technology that delivers a networked, mobile, high-speed communication solution in a similar manner as Wi-Fi.

Making any comparison with the now forgotten IR thing is not fair. The Chinese innovation can replace Wis-Fri *in public areas.

*Firefox spell check prefers Wis-Fri instead of the other spelling. I was told to spell check my posts, so don't blame me., talk to the Firefox people.

Firefox does NOT suggest wis-fri...period.

Now your inventing things...It is the Firefox spell checker..

Now, about in venting thins. Where does this idea that Light signals can not be traced? Then article is about using light for distribution over an area in place of using radio signals. The communication has to be INTER active. It has the same underlining technology as the Wi-Fi equipment.

The reason fort using light, says the article, is to reduce costs. LEDs are super cheap. Certifiable 802.11 devices are not so cheap. To assume that the LEDs hide the identity of the recipient is pure pulp fiction. It has t o be two-way communication. It is called full duplex, if you need a label.

Anyway, it is a real innovation, but not really a discovery. Using visible light means it will really be line-of-sight. Literally. Still, a one-watt LED can be very bright. Potentially a wide area could be covered by two or three transceivers. Perhaps a public library. An Airport, train station, rice paddy or fish market.

Will it be useful here? Not if it is free.

It's an interesting idea but I can't really see it being practical.

I remember years ago my family had a Sony Handycam Hi-8 camcorder that could send the video to the TV via Infra-red light (With the help of a little receiver) - While this worked it was pretty unreliable e.g. if someone walked in front or the alignment got knocked off the picture would fail. And transferring data will be a lot more prone to issues like this compared to composite video from the old camcorder.

I really can't see how this could be more practical than WiFi in any way - As soon as you move the machine between locations your link will LIKELY drop out. I can't see it being cheaper either as the price of mass-produced WiFi gear is so low nowadays.

I don't really see an issue security wise though - The link would likely still be encrypted in some way so in that respect it would offer the same security as WiFi.

Interesting to see that it came from the University of Edinburgh (Where I study) though - I hadn't seen anything about it.

To me, this sounds like a 'research' type project to see what is possible.etc and has maybe been misinterpreted as to it being a technology that is about to come into the consumer market, while it is pretty amazing to see data at that speed transmitted over visible light without issues with interference, I can't see it taking over from RF communications - Mobile phones/PDAs moved from IR to Bluetooth and later WiFi for a reason!Quote

Interesting to see that it came from the University of Edinburgh (Where I study) though - I hadn't seen anything about it.

You should talk to your professers more...camerongray, your point is a valid argument. Until the real technical details are GIVEN, there is to easy way to know it is anything other that wishful thinking.rough.

A quick search shows many 'experts' making commentates about this item as if nit was a real breath of fresh air in the the world of wireless. Yes, line-of-sight and moving objects are real limitation of super-high frequency communications.

Here is an article NOT directly related. But it prides a background of what the issues are in sending a lot of data from one point to another.
http://en.wikipedia.org/wiki/Advanced_Extremely_High_Frequency
The article shows why the military have an interest in this form of radio communication. It also shows why line-of-sight is not the absolute limit.

Now back to topic. It is not impossible for the researches to have made a real discovery. We already know that Gama radiation will penetrate objects like the human body. But the Chinese said it was visible light. Or did they? Are there discreet wavelengths that penetrate in the visible spectrum? Conventional wisdom says 'No, only X-rays do that, never visible light.'

What abo0ut the professor from the UK?
Here is a video of him earlier this year.
http://www.nutshell-videos.ed.ac.uk/harald-haas-d-light/
IMO he is areal ENGINEER doing real research.
He admits to the moving object issue. But pay attention his answer to the obvious question.

Solve : Li-Fi to replace Wi-Fi in China?

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