92 страниц. 2012 год. LAP Lambert Academic Publishing Handover from LTE to 3G cellular networks is considered a high priority item to operators that seek to provide a seamless anywhere anytime mobile service to the subscribers. Interworking procedures between these two networks are ensured in the 3GPP standardization, which the vendors must comply with in their implementation. Services such as video streaming and voice over IP however set stringent requirements for the handover performance. Handover delay should be unnoticeable and handover failures minimized. In order to reach these requirements, this feature needs to go through a development process on the vendor side that consists of thorough functionality, performance and fault correction testing. Test engineers then need to be well aware of the required standards as well as the requirements for quality of service to successfully develop the feature of Inter Radio Access Technology handover from LTE to 3G.