tailieunhanh - Enhanced Radio Access Technologies for Next Generation Mobile Communication - Part 10

Để đạt được các mục tiêu này, Enhanced uplink giới thiệu cải thiện cơ sở stationcontrolled đường lên lịch trình cho phép sử dụng hiệu quả hơn các nguồn tài nguyên vô tuyến đường lên. Base-ga-lập kế hoạch kiểm soát đường lên cũng cho phép | EVOLVED UTRA TECHNOLOGIES 253 P 1 P 2 P 3 P 4 P 5 P 6 P 7 P 8 P 9 P 10 P 11 a Basic structure P 64 Code 1 with code length of 32 P1 1 P1 2 P1 3 P1 4 P1 32 P1 1 P2 1 P1 2 P2 2 Pj 3 P2 3 P1 4 P2 4 P2 1 P2 2 P2 3 P2 4 P2 32 Code 2 with code length of 32 b M-code interleaved mapping M 2 Figure 19. Proposed S- SCH mapping in frequency domain example of basic code length of 16 necessary. However the number of cell IDs generated is limited by the SCH sequence length. Moreover according to the increase in the number of cell IDs defined in the system the cell search time becomes longer. The grouping of cell IDs was proposed which is similar to WCDMA. The overall cell search procedure including the possible cell ID grouping is as follows as indicated in Figure 20. SCH symbol timing detection First the SCH symbol timing is detected following the detection of the OFDM symbol timing FFT window timing . In the hierarchical SCH structure the SCH symbol timing is detected from the correlation between the received signal and the SCH replica in the time domain. The repeated signal waveform arising from the decimation of the SCH sub-carrier in the frequency domain is detected in the autocorrelation based detection with the non-hierarchical SCH structure. Simultaneously the carrier frequency of the target cell which is on the 200-kHz frequency raster defined in the 3G system is detected. The detection and compensation of the frequency drift can also be performed in this step. Cell ID or Cell ID group index detection From the SCH symbol timing detected the S-SCH or direct SCH sequence in the frequency domain is detected in the hierarchical or non-hierarchical SCH structure. The SCH sequence indicates the cell ID or cell ID group index when the grouping of cell IDs is used similarly to that in WCDMA. In addition to the cell ID or cell ID group index the following information can be conveyed by the SCH sequence 254 CHAPTER 7 START STEP 1 STEP 2 STEP 3 Figure 20. Flow of initial cell .