td-scdma关键技术介绍88936.pptVIP

DCA方法 主要方法 慢速DCA（SDCA） 快速DCA（FDCA） 时域 DCA 慢速DCA（SDCA）：动态地分配资源和释放资源 ，比如 时隙优先级固定排队选择时隙和分配资源 时隙优先级基于已用BRU数排队选择时隙和分配资源 快速DCA（FDCA）：在当前用户的无线链路恶化情况下调整用户时隙，改善链路质量 业务建立时，基于质量（RLS）选择时隙以改善用户链路质量 业务进行中，基于质量（RLS）调整时隙以改善用户链路质量 Q A 网络同步主要是要给Node B提供一频率精度优于0.05 ppm 的同步参考，以便Node B无线接口产生正确的信号 也就是说，RNC-Node 间节点同步其实是要在RNC、Node B间了解定时的关系，这样就可以了。 T1/T2/T3/T4: Resolution: 0.125 ms; Range: 0-40959.875 ms TD－SCDMA Node B间节点同步要求Node B间实现BFN的同步 级连形式获得同步源：比如室内覆盖 10ms帧从同步信号的下降沿开始。 同步信号确定了10ms帧、2.56s multiframe interval（256个帧）, and the 4096 frames SFN period 。 传输信道同步：L2同步，在UTRAN、UE间提供L2公共的帧编号（CFN）。在L2每一TBS关联1 CFN，并传递给L1，然后映射到SFN；并在L2实体对等端，对同一TBS接收到的是相同的CFN。 适用所有DL传输信道。 If a DL DATA FRAME or a DSCH TFCI SIGNALLING control frame arrives outside the arrival window defined in the Node B, ,Node B shall send a TIMING ADJUSTMENT control frame, containing the measured ToA and the CFN value of the received DL DATA FRAME SRNC控制，通过调整CN下行发送定时，来减小RNC中buffer delay TD-SCDMA： 1）Inter-slot interference: without frame synchronisation there could be leakage from an UL timeslot into a DL timeslot, especially crucial for the UE due to the potentially close distance between UEs and the near-far effect. 2）neighbouring cell monitoring: In TDD mode, certain measurements have to be performed in certain parts of certain timeslots of neighbouring cells. Without cell synchronisation, the UE would have to synchronise itself before being able to perform the measurements. In a multipath environment, the original transmitted signal is reflected on obstacles such as buildings or mountains, and the receiver receives several copies of the signal with different delays. Actually, from each multipath signal point of view, other multipath signals are considered as interferences and are suppressed thanks to the processing gain after despreading. However, a further benefit is obtained if several multipath signals are combined together using a rake receiver. The rake receiver has multiple fingers, each for a multipath c