How UE in LTE knows Antenna number

[jbada]

Hi Forum,

I would like to open this thead in order to undestand a little better how the UE in LTE knows the number of Antennas in DL.

According my undestanting the UE detects the number of antennas when it decoded the PBCCH. In this channel there is a CRC mask (16 bits) that is built taking in consideration the number of antennas in the transmission side. In this way the mobile can know of we have 1, 2 o 4 antennas.

I don't know if there are others ways.

Many thanks

[ninjafine]

Hi Forum,

I would like to open this thead in order to undestand a little better how the UE in LTE knows the number of Antennas in DL.

According my undestanting the UE detects the number of antennas when it decoded the PBCCH. In this channel there is a CRC mask (16 bits) that is built taking in consideration the number of antennas in the transmission side. In this way the mobile can know of we have 1, 2 o 4 antennas.

I don't know if there are others ways.

Many thanks

Hi! There is an IE antennaInfo in RRC Connection Setup. You may see an example from below:

antennaInfo : explicitValue
explicitValue
transmissionMode : tm3
codebookSubsetRestriction : n2TxAntenna-tm3
n2TxAntenna-tm3 : 11
[0 ] : 1
[1 ] : 1

According to the number of CodebookSubsetRestriction bits from 3GPP TS 36.213:
36_213_Table7_2_1_b.jpg
we can find that the transmissionMode = tm3 and number of antenna ports is 2.

[firstmaxim]

By reading the Reference Signals that are interleaved in the OFDMA frame structure.

Antenna 1 and Antenna 2 have reference signal transmitted on different areas of the Frame. Those positions of frame in Antenna 1 where Ref Signals are TX are DTX'ed in the frame transmitted by Antenna 2. And, vice versa.