curs only if the voice over high speed packet access (VoHSPA) service is available on 3G network. During PS-PS inter-system handover, the SGW entity acts as an anchor point, which will hide the terminal mobility to the IMS network. PS-CS inter-system handover is described relative to the service centralization and continuity in Chapter 8. The handover procedure is activated by the source eNB entity from measurements on the radio signal made by: - the eNB entity for the uplink direction; - the mobile for the downlink direction, for the serving and neighboring cells. These measures are recovered by the eNB entity in RRC MeasurementReport messages. Handover The handover procedure takes place in three phases: - the preparation phase corresponding to the decision of cell change and resource reservation; - the execution phase corresponding to the mobile connection to the target eNB entity; - the completion phase corresponding to the establishment of final bearers and the release of the old resources. The intra-system handover is carried out with a disconnection of the mobile with the eNB entity, whose duration depends on the following: - the synchronization of the mobile on the primary synchronization signal (PSS) and secondary synchronization signal (SSS) transmitted by the target eNB entity; - the discovery of the physical random access channel (PRACH); - the random access procedure; - the connection procedure to the target eNB entity. During the preparation of the intra-system handover, a unidirectional and temporary bearer is created between the source and target eNB entities for the downward direction. During the execution of the handover, the incoming data are forwarded to the target eNB entity that stores and delivers it to the mobile when it connects. For voice and conversational video communication, this operation causes an increase in packet jitter, which is corrected using the real-time transport protocol (RTP), to a certain limit. If the jitter of packets from end to end becomes too large, the packets are d