SON Introduction

Self-organizing networks (SON) are the attempt to simplify and speed up the planning, configuration, management, optimization and healing of mobile communications networks. Well-designed and efficient SON functions are able to achieve and maintain high levels of network performance by continuously finding improvement patterns that may not be easily distinguishable to an expert. This is done so via the modification of various network parameters and by using rollback algorithms. These operations can be performed efficiently due to the availability of rich statistical models on Key Performance Indicators (KPI), their dependencies on one another and their interactions with each other. 

Aim -

• Reducing the operating cost by reducing the level of human intervention in network design, build and operation. 
• Reducing capital expenditure by optimizing the use of available resources, 
• Protecting revenue by reducing the number of human errors.

Definition -

• SON, can be defined as a set of use cases that govern a network including the planning, set up and maintenance activities. In this way the self-organizing networks enable the network to set itself up and then manage the resources to enable the optimum performance to be achieved at all times.

The significant increase in the number of mobile users as well as the amount of online content has caused the demand for high-speed data to rise exponentially. This has played a major role in recent developments in mobile networks. In order to accommodate this growing demand, mobile operators are having to deploy increasingly complex networks. These networks are comprised of multiple radio access technologies, several different cell types and various users, all of whom have different Quality of Service (QoS) requirements.

Mobile operators now need to be able to manage these ever-increasingly complex networks efficiently with minimal costs. In order to do this new and existing networks need to be managed with minimal manual efforts. Thus, SON functionalities are essential in future as well as existing networks.

The complexity of LTE system also place new demands on the Operations and Maintenance of the network. Self-Organizing Networks (SON) is seen as one of the promising area for an operator to save operational expenditures and this is the main reason for mobile operators to implement SON to help decrease their capital and operating expenditures. SON functions can help decrease the costs in all 3 stages (planning, deployment and operation) of a network life cycle.

Main Drivers for SON 

The main drivers for SON are:

1. The number and structure of network parameters have become large and complex; 
2. Quick evolution of wireless networks has led to parallel operation of 2G, 3G, EPC infrastructures; 
3. The rapidly expanding number of Base Stations (especially Home eNB) needs to be configured and managed with the least possible human interaction. SON aims to configure and optimize the network automatically, so that the interaction of human can be reduced and the capacity of the network can be increased.

The main elements of SON include:

Self configuration: The aim for the self configuration aspects of LTE SON is to enable new base stations to become essentially "Plug and Play" items. They should need as little manual intervention in the configuration process as possible. Not only will they be able to organise the RF aspects, but also configure the backhaul as well. 

Self optimisation: Once the system has been set up, LTE SON capabilities will enable the base station to optimise the operational characteristics to best meet the needs of the overall network. 

Self-healing: Another major feature of LTE SON is to enable the network to self-heal. It will do this by changing the characteristics of the network to mask the problem until it is fixed. For example, the boundaries of adjacent cells can be increased by changing antenna directions and increasing power levels, etc..