When people ask, “what do you do?” I sometimes say, “I turn light bulbs into high speed WiFis”. This usually receives a positive response, raised eyebrows, and then often this question. “So why would you want to do that?”
There are many good answers to this question since the reasons to use light instead of radio to carry data are as varied as the applications themselves. A future post will consider the top 10 applications of Visible Light Communications (VLC), but let us just consider one area of pain requiring VLC medicine for now.
The radio spectrum is full to bursting and already there is considerable difficulty finding radio capacity to support media applications. Cellular is struggling and WiFi is not equipped to cope with the growth of wireless data being experienced. As far back as 2009 AT&T suffered major capacity shortages as iPhone users consumed data capacity at an alarming rate .
In June last year US President, Barack Obama, asked for the amount of commercially licensed radio spectrum to be doubled over ten years. This is achieved by freeing up under-utilised bands such as analogue TV bands. However, this ten year plan cannot cope with current demand which is more than doubling each year. Major pain is on its way!
Our home and office WiFis are struggling to cope with current demand and yet more devices are using larger and larger data rates: audio devices, games consoles, phones, laptops, internet TVs, etc. We are moving from standard video to HD and now to 3D HD, each increasing data demands. Yet more pain!
By using VLC for short range, high data rate communications a lot of the capacity can be off loaded to the visible spectrum using optical air interfaces for WiFi and cellular femto cells. VLC many not be the ‘cure all’ medicine, but is does have the capacity to alleviate a lot of the pain. In spectral terms there is 10,000 times more capacity in the visible band compared to the radio bands. That is a very big medicine cabinet and it is now time to open it!
 New York Times, “AT&T to Urge Customers to Use Less Wireless Data”, Jenna Wortham, 9th December 2009 http://www.nytimes.com/2009/12/10/technology/companies/10iphone.html