ymbol Physical Cell id E-UTRAN Cell Global ID E-CGI of the cell is transmitted as a part of SystemInformationBlock Type 1 Figure 2-6. Physical cell ID and E-UTRAN cell global ID During a UE attach, the eNodeB sends across the measurement configurations to the UE. When the UE moves away from the serving cell, it starts reporting measurements indicating the strongest cell or cells to the eNodeB for any handover-related actions. The measurement report consists of only the PCID of the cells that match the measurement criteria. In such events, it is very possible that the UE reports a PCID that is unknown to the source eNodeB. In this case, the base transceiver station BTS configures the UE to further report the E-CGI (E-UTRAN cell global ID) for the unknown PCID reported cell. Upon the UE reporting the E-CGI for the new target cell, the source eNodeB will try to derive the IP information for the newly discovered neighbor. Figure 2-7 depicts this process. CHAPTER 2 SELF-ORGANIZING NETWORKS IN LTE DEPLOYMENT ENodeB 2- Target cell ENodeB 1- Serving cell Figure 2-7. Neighbor cell discovery X2 Configuration Discovery of the Neighboring Site The E-CGI reported by the UE will now be used by the source eNodeB to discover the neighboring eNodeB. The source eNodeB will exchange the transport network layer (TNL) configurations with the target eNodeB via the MME by means of an information transfer procedure. Considering that the MME has already established the S1AP connections with the source and targeted eNodeBs individually, the eNodeBs can now exchange their configurations by means of transparent containers, as shown in Figure 2-8. eNodeB2 eNode81 1. S1 setup procedure (ECGI of cells for the eNodeB are known by MME) 3.eNB CONFIGURATION TRANSFER to eNode81 requesting for TNL 2. UE reports discovered cell-to configuration Info for X2 connection attached cell in eNodé8 2 4 .MME CONFIGURATION TRANSFER requesting for eNode81 TNL configuration information 5 .eNB CONFIGURATION TRANSFER with TNL configuration information 6 .MME CONFI