UE如何区分PDSCH中传输的DCCH和DTCH呢？

BCCH，CCCH，DCCH、DTCH 都映射到 DL-SCH 再映射到 PDSCH，UE是如何区分这三者呢？
我知道用SI-RNTI加扰的PDCCH对应BCCH，那如何区DCCH，DTCH，它们都是用C-RNTI加扰的吧

possibly by the LCID field of MAC header

00000 CCCH
00001-01010 Identity of the logical channel

so LCID = 0 means CCCH(SRB0)
LCID = 1 means DCCH(SRB1)
LCID = 2 means DCCH(SRB2)
all other LCID corresponding to DTCH(DRB)

非常感谢，向大牛学习！