Recently, and due to quick technology evolution, and the need for mobile communications to replace the old-fashioned fixed ones to allow mobility and flexibility in communication everywhere, the need for higher speed communication became obstructive. For the data transfer process, wired communication made a huge revolution and achieved a lot of progress. Although, a day after another the need for higher data rate technologies become urgent. Due to this reason, scientists and experts work hard to find new techniques to serve out the largest number of users with higher transmission data rate and free to move technique. 3G, 4G, Wi-Fi and other technologies can permanently do that, but as time goes, the necessity to transmit and receive data with much higher data rate, faster, more secure and cheaper technique is desired. For new and more sophisticated technique, as any current one, a range of frequencies is mainly required. But recently, frequency spectrum becomes fully used for other applications. So, we are looking for exploiting the un-used range of frequencies in order to solve the RF bandwidth limitation problem. From this point, we find that the range between 405THz to 790THz (visible light range) is un-exploited so we trend to use it to invent a new effective technology which is Li-Fi (light fidelity) technology.
Li-Fi (Light Fidelity) is a new technique which uses visible light communication (VLC) for transmitting data through a LED light bulb by varying the light intensity faster than the human eye can follow. If the LED is one then the receiver registers a binary 1, otherwise logic zero is registered (2). This technique has a lot of advantages some of them are:
Advantages
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It carries much more information compared with Wi-Fi, 3G and 4G.
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An excellent solution for the bandwidth limitation.
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High data rate exceeds 10 Gb/s.
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More secure with lower cost.
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Does not cause electromagnetic interference.
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Low power consumption.
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It leads to internet of things.
On the other hand, we expect to face some challenges such as:
Challenges
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Presence of day light.
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Need for line of sight process.
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Interference with other light sources.
Methodology
In our approach, we used our own designed circuit for both transmitter and receiver.
In our design, we used OOK modulation scheme in its simplest form, at a bit rate of 300 Bps.
In the first phase our methodology was used for proof of concept with a bit rate equals to 300 Bps, and the second phase of the project introduces some enhancement on the circuits like increasing the distance, preparing the system to handle several types of data (audio, video …etc), decreasing the operational energy of the circuit, decreasing the size of the circuit and its complexity. Moreover, we established two detached transceivers.
Our circuit in the first phase faced many problems; the transmitter side hasn’t been changed, but in the receiver side the TC9400 (15) frequency to voltage convertor was slow, complex and gave a low bit rate up to 300 Bps so, it was urgent to replace the TC9400 (15) by more efficient demodulation circuit.
So, we have replaced the receiver circuit with a much simpler, cheaper, higher bit rate (up to 2.4kBps), higher speed and lower power consumption.