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Trong bước lập kế hoạch tiếp theo các khu vực thống trị cho mỗi tế bào đã được tối ưu hóa. Trong bối cảnh này, sự thống trị liên quan đến các điều kiện tuyên truyền. Antenna nghiêng, mang và các địa điểm trang web có thể được điều chỉnh để đạt được các khu vực thống trị rõ ràng cho các tế bào. | Radio Resource Management 259 High capacity sites with two frequencies fl and f2 Macro layer with frequency fl Micro layer with frequency f2 Figure 9.31. Need for inter-frequency handovers between WCDMA carriers 1 RNC commands UE to start inter-frequency measurements with compressed mode. Measurement trigger is RAN vendor specific algorithm 2 UE finds P-SCH peaks. The more peaks the UE can receive with its matched filter the longer the WCDMA cell identification takes. The cell identification time depends on Number of multipaths 3 UE identifies the cell with S-SCH and CPICH and reports measurements to RNC Number of cells within detection range Number of already found cells Size of the neighbourlist 4 RNC sends handover command to the UE Cell identification typically 5 seconds. Figure 9.32. Inter-frequency handover procedure identification time depends mainly on the number of cells and multipath components that the UE can receive in the same way as with intra-frequency handovers. The requirement for the cell identification in 3GPP is 5 seconds with CPICH Ec I0 20 dB 6 . 9.3.4 Summary of Handovers The WCDMA handover types are summarised in Table 9.9. The most typical WCDMA handover is intra-frequency handover that is needed due to the mobility of the UEs. The intra-frequency handover is controlled by those parameters shown in Figure 9.16. The intrafrequency handover reporting is typically event-triggered and RNC commands the handovers according to the measurement reports. In the case of intra-frequency handover the UE should be connected to the best Node B s to avoid the near-far problem and RNC does not have any freedom in selecting the target cells. 260 WCDMA for UMTS Table 9.9. WCDMA handover types Handover type Handover measurements Typical handover measurement reporting from UE to RNC Typical handover reason WCDMA intra-frequency Measurements all the time with matched filter Event-triggered reporting - Normal mobility WCDMA GSM Measurements started only Periodic
