tailieunhanh - Wideband tdd wcdma for the unpaired spectrum phần 9

UE hoàn thành thủ tục này thông qua một kênh đường xuống thông thường gọi là đồng bộ hóa Channel (SCH / P) và thông qua midamble trên kênh tiểu học thông thường điều khiển vật lý (PCCPCH / P). Sau đây, chúng ta sẽ thả các hậu tố '/ P' vì đơn giản ký hiệu. SCH bao gồm một luật đồng bộ hóa tiểu học (PSC) và ba mã đồng bộ hóa Trung (SSCs). PSC và SSCs có chiều dài là 256 chip. PSC là một mã unmodulated truyền. | 198 Radio Resource Management 5. SIR As for the UE the Signal to Interference Ratio SIR is measured on a specified DPCH code and is defined as RSCP ISCP SF where SF is the spreading factor of the DPCH code. A number of timeslot samples are averaged together to produce a reliable measurement. 6. BER Transport Channel BER is an estimation of the average bit error rate BER of a specific DCH or USCH. 7. RX Timing Deviation The Rx Timing Deviation measurement is the estimate of the difference in time between the start of Node B reception of an UL burst and the start of transmission of Node B s timeslot. Intra-Cell vs Inter-Cell Interference In general the interference in CDMA systems is of the Intra-Cell and Inter-Cell type. The former arises from multiple users in a cell whose signals overlap on time and frequency but are separate in code domain. Since in WTDD users are assigned different timeslots also the Intra-Cell Interference is limited to only those users active in the same timeslot. In other words the Intra-Cell Interference is reduced to Intra-Timeslot Interference Since the maximum number of users in a timeslot is limited to 16 the maximum Intra-Cell interference is quite limited. Another very significant advantage comes about due to the potential use of Multi-User Detectors for WTDD. Such detectors theoretically eliminate interference among users in the same timeslot thereby potentially removing all Intra-Cell Interference altogether In such cases the WTDD systems would only have to minimize Inter-Cell Interference which is due to users active in an overlapping Timeslot and same carrier frequency in another cell. If neighboring cells are assigned different timeslots then the distance to interfering cells is increased thereby reducing Inter-Cell Interference also. Timeslot Fragmentation The RUs required by a service as explained in Section are allocated to various timeslots. If the number of timeslots used is M then a small M is said to .