The random access procedure is performed for the following events related to the PCell:
- Initial access from RRC_IDLE;
...
The random access procedure is also performed on a SCell to establish time alignment for the corresponding sTAG.
As you see in the following figures, for Rel 8,9,10 there is no special tag for each component carrier, meaning that even in Carrier Aggregation single Timing Advanced value apply to all the component carriers. But in Rel 11, the first 2 bits are allocated to indicate whether the value is for PCC or SCC. If TAG id is 0, it means it is for PCC.
kqkqsmd 发表于 2024-4-10 14:44
As you see in the following figures, for Rel 8,9,10 there is no special tag for each component car ...
这段话是描述什么内容的?
时间: 2024-4-10 17:41
作者: kqkqsmd
本帖最后由 kqkqsmd 于 2024-4-10 17:42 编辑
oooooooo 发表于 2024-4-10 17:04
这段话是描述什么内容的?
这个就是描述TA的。本来贴个图,但是好难用release11的白皮书上,也看到了
As of 3GPP Release 10 multiple carriers in uplink direction were synchronized due to the fact that there was only a single Timing Advance (TA) for all component carriers based on the PCell.
To enable multiple timing advances in 3GPP Release 11, the term Timing Advance Group (TAG) was introduced [4]. A TAG includes one or more serving cells with thesame UL timing advance and the same DL timing reference cell.