Self Organizing Networks
Mobile Network Operators (MNO) are constantly optimizing their networks. MNO look towards automation technologies, processes, and procedures as a means of more efficiently managing their large networks, which consist of tens of thousands of base station with hundreds of settings each.
Self-organizing Networks (SON) provide automation solution for planning, configuration, management, optimization, and healing of mobile RAN functions that emerged out from 4G LTE environment and IMS technology. SON provides efficient, and in some cases, programmatic means of fine tuning cellular networks. SON systems are part of next generation OSS/BSS technologies for mobile network operators to automate previously manual network optimization procedures.
SON can fix fundamental problems (i.e. the tire is out of alignment analogy), such as poor coverage and/or dropped calls in an area and it can also be used for short-term, real-time issues (and then potentially be put back the way the network was in the first place. For example, the network may need optimization locally for a specific event such as a sporting event or live show/concert. In all cases, SON is designed to support wireless carriers desire to provide a multitude of different services with high quality of experience for the end-user.
SON capability can be broken down into three main functions:
- Self-Configuration: This capability allows small cells to be able to support plug-and-play architecture of automatic connection establishment, software downloads/upgrades, and configuration parameters.
- Self-Optimization: This provides the ability for small cell nodes to change parameters based on KPI measurements by itself and those reported by the UE.
- Self-Healing: In the event of certain small cell node failures, remaining small cells should be able to adjust their parameters and algorithms to provide required coverage and capacity in the failed nodes coverage area.
These capability needs and the overall SON requirements translate into following strategic business and technical requirements for the Communications Service Provider (CSP):
- Interference Mitigation: Support intelligent interference management to minimize capacity and coverage loss as needed.
- Deployment Automation: Support automation of small cell deployments and configuration.
- Intelligent Load Balancing: Support capability to intelligently balance traffic within a group of small cells in a target site location.
- Support Multi-Vendor Interoperability: Support ability to seamlessly deploy and operate multi-vendor small cells.
- Intelligent Radio Resource Allocation: Support ability to intelligently allocate radio resources between different RAT types (LTE and Wi-Fi) in a given small cell
SON can be deployed in three modes:
- Centralized SON: Client-server based SON architecture with a centralized SON platform which is located within the core network and closely integrated with the OSS platforms
- Distributed SON: Distributed SON architecture where the functions are distributed among the network edge elements like eNodeB
- Hybrid SON: Combination of both centralized and distributed SON architectures
Based on all of the aforementioned capabilities, CSP HetNet deployments rely upon SON to provide seamless network operations and improved Quality of Experience (QoE) for end-users. SON is also expected to bring both CSP and end-user benefits. The benefits to the network operator include more efficient/effective operations as well as reduction of both CAPEX and OPEX expenditures.
The key for successfully achieving desired results is for deployed small cells is to have data-driven SON solutions that continuously and automatically monitor Key Performance Indicators (KPI), which may consist of various Quality of Service (QoS) metrics from the RAN nodes to optimize and improve the network performance. One of the ways to achieve this is to use OSS data to first detect coverage, capacity, and other issues in real time and automatically adjust the network behavior to address the issue.
One KPI example for use with SON in LTE networks is "Reserved Quality", which a means of managing QoS and QoE.
For example, when it is detected that more than the supported users are connected to a single macro or small cell RAN node, the SON system should automatically improve the coverage by adjusting the parameters for adjacent Cell nodes such that they can start providing coverage in the target area and start offloading some of the users. This results in a dynamic network that can respond to actual changes in RF conditions and user traffic demand.