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Radio network planning and optimisation for umts 2nd edition phần 5

Nếu hai nhà khai thác đã đồng vị với nhau BSS của họ là không quan trọng, từ đó các nhà điều hành thứ hai của BS sẽ lệnh MS để giảm sức mạnh của nó. Trong một trường hợp lý tưởng sẽ không có bất kỳ vấn đề, kể từ khi các nhà khai thác đang sử dụng các tàu sân bay tần số khác nhau và sẽ không có sự can thiệp giữa chúng. | Radio Resource Utilisation 231 Table 4.5 The impact of transmission gap length on GSM received signal strength indicator measurements. TGL slots No. of GSM RSSI samples No. of GSM RSSI samples per slot Time to complete eight GSM RSSI measurements three samples per measurement 3 1 0.33 960 ms 4 2 0.50 480 ms 5 3 0.60 320 ms 7 6 0.86 160 ms 10 10 1.00 120 ms 14 15 1.07 80 ms inner-loop PC to recover. In the case of CM by HLS larger TGLs require the use of lower transport format combinations and result in lower L2 throughput. In the case of CM by SF 2 larger TGLs require the use of the double-frame approach meaning that two radio frames rather than a single radio frame have their spreading factor reduced. Table 4.5 presents the relationship between TGL and the minimum requirement for the UE s ability to sample GSM RSSI. These figures have been extracted from 9 . The third column shows the efficiency with which measurements are made. Also included in the table is the equivalent time required to complete eight GSM RSSI measurements based upon three samples per measurement and a TGPL of four radio frames. GSM RSSI measurements are made without acquiring GSM synchronisation and do not require the CM transmission gap to coincide with a particular section of the GSM radio frame. The measurement efficiency becomes relatively poor for TGLs of less than seven slots. A TGL of seven slots balances the efficiency but with an impact on the inner-loop PC. In the case of BSIC verification the frame structure and timing of the GSM system has a more significant impact on the required TGL. The GSM system is based on an eight-slot radio frame structure with a duration of 4.615 ms. The first slot of each frame is dedicated to the BCCH. The BSIC is broadcast periodically within the SCH of the BCCH. The UE has no knowledge of the timing of the GSM system and must capture 9 slots worth of GSM data to be sure of capturing the BCCH. A CM TGL of 7 slots is equivalent to 4.667 ms and provides a