Machine Learning-Based Recommender Systems to Achieve Self-Coordination Between SON Functions

The deployment, operation and maintenance of complex cellular networks are managed autonomously by multiple concurrently executing Self-Organizing Network (SON) functions with dedicated objectives, that can often negatively impact the functioning of each other. It is essential to avoid the blinkered view to their individual targets and consider a holistic approach towards identifying the best possible coordination between them, in order to achieve desired overall network gains while ensuring stable and robust network operation. The designing of appropriate SON-coordination mechanisms is quite challenging as it requires comprehensive modelling of all the complementing and conflicting interactions among them. This article discusses the application of Machine Learning based online Recommender Systems to model the dynamics between SON functions. To evaluate its applicability, in this work, the focus is to jointly implement two intertwined SON functions - Inter Cell Interference Coordination (ICIC) and Coverage and Capacity Optimization (CCO), to implicitly handle their conflicts and achieve the desired trade-off between coverage and capacity by optimizing a joint objective. The proposed cooperative learning and distributed configuration enforcement based ICIC-CCO coordinated SON solution has been evaluated on a system-level LTE network simulator with varied traffic distributions. It has been observed that the outage situations in the network are significantly reduced while still achieving high Signal-to-Interference Ratios (SIRs), even with reduced transmit power settings on several occasions.

I. Introduction

The densification of base-station deployments to serve the diverse and ever-increasing demands in services along with the simultaneous operation of multiple Radio Access Technologies (RAT) has increased the complexity of network design and operation manifolds. Self-Organizing Network functions (SFs) have been introduced by 3GPP [1] as sustainable, cost-effective autonomous solutions that can optimize the utilization of network resources and correspondingly enhance the network performance of such complex heterogeneous networks. The SFs monitor and evaluate several different network and service Key Performance Indicators (KPIs) and cognitively adapt to the dynamically changing network environments by adjusting the required configuration parameters. The key functional areas in Self-Organization of mobile communication networks involve Self-Configuration, Self-Optimization, Self-Healing and Self-Coordination.