The outstanding advances in computing as well as the explosion of devices and services requirements are making communication mobile networking more and more complex to manage. In addition, multimedia services such as provided by the IP Multimedia Subsystem (IMS) require a dynamic Quality of Service (QoS) management. However, traditional Long Term Evolution (LTE) networking approaches have become too closed and limited in terms of providing Quality of Service (QoS). For this purpose, it has been necessary to look for new approaches. Among these approaches is the integration of the Software Defined Network (SDN) in the LTE network. With this approach the LTE mobile network will benefit from the SDN features to separate the control plane from the data plane and to enable a dynamic configuration of network resources and then a flexible QoS management. This paper presents a new architecture SDN-based for LTE packet core to enhance the QoS management. The architecture is implemented and evaluated for a Video on Demand (VoD) by testing the Quality of Experience (QoE) in terms of the Video Mean Opinion Score (VMOS).