Enhanced Mobility Load Balancing Optimisation in LTE

Self-Organising Network (SON) use cases are seen as key enablers of efficient Long Term Evolution (LTE) system operation. Mobility Load Balancing Optimisation (LB) is a prominent SON use case defined by 3GPP with the scope of balancing the load in a given coverage area by reconfiguring the handover thresholds. When overload is detected at a given cell, the LB reduces the handover thresholds of those user equipments that can be redirected to the underutilised neighbouring cells. This mechanism improves the user plane performance in the overloaded cell. Despite the potential benefits, the available LB mechanisms have two major deficiencies, both of them causing user experience degradation: on the one hand, they tend to overestimate the load on the air interface, resulting in unnecessary handovers; on the other hand, they are either transport agnostic or have limited capability to consider the transport load during their decision process. This paper provides an overview of the LB related problems and proposes an improved solution including accurate evaluation of the radio load and a transport aware mechanism for end-to-end optimisation. The performance of the solution was evaluated by simulations.