LTE SIB1时频资源
1.时域资源
参考3GPP 36.331 – 5.2.1.2Scheduling
The SystemInformationBlockType1 uses a fixed schedule with a periodicity of 80 msand repetitions made within80 ms. Thefirst transmission of SystemInformationBlockType1 is scheduled insubframe #5 of radio frames for whichthe SFN mod 8 = 0, and repetitionsare scheduled in subframe #5 of all other radio frames for whichSFN mod 2 = 0.
传输周期 = 80 ms
SIB 1时域长度： 整个subframe 5上的data region都有可能.|
SIB1传输 |
The first transmission |
repetitions |
|
SFN满足条件 |
SFN mod 8 = 0 |
SFN mod 2 = 0 |
|
Subframe满足条件 |
subframe #5 |
subframe #5 |
2.频域资源
Sib1频域资源的位置不固定，是由SI-RNTI加扰的PDCCH来指示。
UE需要先在子帧上使用SI-RNTI盲检加扰的PDCCH，才能知道该子帧是否存在Sib1消息. 盲检的过程可以参考我的博文：LTE x-RNTI (2)
众所周知：PDCCH is a physical channel that carries DCI.那种DCI format 可以用SI-RNTI 加扰呢？
答案就是：DCI 1A/1C.
如下表格来自：sharetechnote.
|
RNTI Types |
DCI Format Applicable to the RNTI Type |
|
SI-RNTI, P-RNTI, RA-RNTI |
1A, 1C |
|
C-RNTI, SPS C-RNTI |
0, 1A, 1B, 1D, 2, 2A, 2B, 2C, 4 (2B,2C,4 is for Rel 10 or later) |
|
M-RNTI |
1C |
|
TPC-RNTI |
3, 3A |