We propose in this paper a simulation implementation of Self-Organizing Networks (SON) optimization related to mobility load balancing (MLB) for LTE systems using ns-3 [1]. The implementation is achieved toward two MLB algorithms dynamically adjusting handover (HO) parameters based on the Reference Signal Received Power (RSRP) measurements. Such adjustments are done with respect to loads of both an overloaded cell and its cells' neighbours having enough available resources enabling to achieve load balancing. Numerical investigations through selected key performance indicators (KPIs) of the proposed MLB algorithms when compared with another HO algorithm (already implemented in ns-3) based on A3 event [2] highlight the significant MLB gains provided in terms global network throughput, packet loss rate and the number of successful HO without incurring significant overhead.