For next-generation cellular networks, operators are hoping to limit their financial payout by relying on self-organizing networks (SONs). In addition to increasing revenue, such networks will offer improved performance and efficiency. The 3GPP/NGMN and SOCRATES project has studied various SON use cases in terms of self-configuration, self-optimization, and self-healing. To help to clarify the available options, ReVerb Networks has released a white paper focused on antenna remote-electrical-tilt (RET)-based SON solutions. It also provides an overview of SON functions based on other parameters, referring to them as "parameter-based SON."
The four-page document is titled, "Comparison of Antenna-based and Parameter-based SON with Load-Balancing and Self-Healing Cases." It begins by discussing load balancing, which aims to uniformly spread traffic among neighboring cells to the fullest extent possible. Instead of tuning antenna parameters like tilt, parameter-based SON usually adjusts the handover parameters to achieve such load balancing. Aside from handover offset, two additional control parameters should be carefully set: target load level and maximum accepted load threshold.
The project also studied the cell-outage-management use case, which falls under self-healing. In addition to restoring operation should a cell-outage event occur, self-healing requires effective cell-outage detection. Compensation occurs by automatically adjusting the parameters in surrounding cells, such as received power, antenna parameters, and modulation index. Of course, quality and performance are typically compromised when this occurs.
That said, the operators decide on their "minimal-quality threshold" and take action accordinglysometimes maintaining quality of service among selected user groups to maximize overall coverage. By altering the antenna tilt, the paper concludes that tilt-based load balancing results in truly changed cell coverage. In contrast, parameter-based SON solutions inevitably cause system degradation.
