The vision of self-organizing networks (SON) is that future radio access networks needs to be easier to plan, configure, manage, optimize and heal. This vision is in line with the views of 3GPP (3rd Generation Partnership Project) and the NGMN (Next Generation Mobile Networks) group.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).
SON has been codified by the 3GPP Release 8 specifications in a series of standards including 36.902, The first technology making use of SON features will be UMTS Long Term Evolution. The LTE specification inherently supports SON features like Automatic Neighbor Relation (ANR) detection, which is the 3GPP LTE Rel. 8 flagship feature.
Newly added base stations should be self-configured in line with a ‘plug-and-play’ paradigm, while all operational base stations will regularly self-optimize parameters and algorithmic behavior in response to observed network performance and radio conditions. Furthermore, self-healing mechanisms can be triggered to temporarily compensate for a detected equipment outage, while awaiting a more permanent solution.
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) Optimizing 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.
Self-Organizing Networks are commonly divided into three subareas:
Self-configuration strives towards the ‘plug-and-play’ paradigm in the way that new base stations shall automatically be configured and integrated into the network. This means both connectivity establishment, and download of configuration parameters and software.
The base station parameters can be regularly adjusted, based on both base station and mobile station observations. One of the first SON features establishes neighbor relations automatically (ANR), while others optimize random access parameters or mobility robustness in terms of handover oscillations.
When some nodes in the network become inoperative, self-healing mechanisms aim at reducing the impacts from the failure, for example by adjusting parameters and algorithms in adjacent cells so that other nodes can support the users that were supported by the failing node.
The need of SON
- Generally as the data rate of a technology gets higher, the cell coverage (range) gets smaller. It means we need to deploy more eNBs.
- In LTE we would see a lot of pico cells and femoto cells even inside of our house. So it would be practically impossible or highly costly to send specialized engineer to install and configure all of those hardware.
- If we can make the hardware configure itself, we can have less skilled person just setup the hardware at any location and power on, or we can just deliver the hardware (e.g, femtocell) to a home and let them just plug in the power.
- Normally as new (advanced) technology introduced, number of configuration parameters gets exponentially increased, so manual tuning of all those parameters whould be almost impossible.
- Now we have all the different technologies (CDMA, GSM, WCDMA, LTE) are running simulteneously and in many cases these technologies interact each other. This makes the mannual optimization almost inpractical.ANR will help in determining the best available cells and handover definitions would be simpler in that case.