SON stands for Self Organizing Network. What does this mean ? Ideally it means that just add a eNB wherever you want to put and just connect power and switch on, it would configure all of its configuration by itself and makes itself ready for service.
If you think a whole mobile network as a single PC, SON is like 'Plug-and-Play' functionality. (just Plug a any hardware (e.g, Keyboard, Printer etc) and it would play).
Normally when a system operator construct a network, they go through following steps.
i) Network Planning
ii) Bring the hardware (e.g, eNB) to the locations determined at Network Planning Process
iii) Hardware installation
iv) basic configuation
v) Otimizing parameters
Ideal goal of SON is to automate large portions of step i) and all of step iv), v) meaning that the installed system do all of iv), v) by itself.
In more formal way, SON framework can be illustrated as follows.(This illustration is from from nomor research - Self-Organizing Networks (SON) in 3GPP Long Term Evolution )
But we know from experience that any Fancy idea takes very long time to be fully implemented and adopted by everybody and sometimes the idea would disappear even before it is realized. SON itself is at its very early stage (as of now, May 2012 at least). I would say it is at the stage of doing only a portion of step iv). I personally don't think SON concept would disappear but it would take pretty long time to be realized at the level of Plug-and-Play of our PC component.
You may have a question "Why we need this kind of idea ?", "Why we want to achieve this ?"
Typical answers that I can think of is
Major Goals for SON
Major Goals for SON is to achieve meeting the following two use cases. (This is defined in 3GPP TR 36.602)
For now (as of ETSI TR 136 902 V9.3.1 (2011-05)), Achieving 'Optimal Converage' is at higher priority than achieving 'Optimal Capacity'.
Use Cases for SON
Following is the list of Use Case described in ETSI TR 136 902 V9.3.1 (2011-05). Each of these items is huge item. Basically 3GPP describes 'what is to be achieved' but does not describe 'how they can be described'. Most of the items are up to network operator and hardware manufacturers. (I will keep updating details as find time)
Further Readings :
Presentations on YouTube :