Hello Experts.
What is the meaning of antenna port 1001 or 4001?
I mean, what is indication for these numbers:
1 0 0 1 , 4 0 0 1
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The frame structure and physical resources the UE shall assume when receiving downlink transmissions are defined in Resource Grid.
The following antenna ports are defined for the downlink:
- Antenna ports starting with 1000 for PDSCH
- Antenna ports starting with 2000 for PDCCH
- Antenna ports starting with 3000 for channel-state information reference signals
- Antenna ports starting with 4000 for SS/PBCH block transmission
The UE shall not assume that two antenna ports are quasi co-located with respect to any QCL type unless specified otherwise.
Link: Downlink overview
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Thanks!
But I mean what is meaning with antenna number itself?
Ex. for 1000, what this meaning?
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A group of antenna elements can form an antenna port.
So one group of antenna form one port which is 1000 another set of antenna elements from antenna port 1001.
Likewise other ports can be formed.
Imagine a large antenna array panel where number of antenna elements are mapped to different antenna ports to support beamforming.
Different type of transmission are called with different naming terminology as per 3GPP.
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Thanks again.
But how UE knows gNB assign port 1000 not port 1001?
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Antenna element to antenna port mapping is not visible to UE.
gNB only informs about the number of streams to the UE.
If we take example of PDSCH, each port will have its own DMRS which will be used to decode the corresponding PDSCH transmission via that port.
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UE just need to know in which PRB / RE and in which slot / symbol comes the DMRS for each antenna port.
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I have tried explaining about the antenna ports in this video, consider checking this out
Watch Video on YoutTube: 
https://youtu.be/b_2pLRs37tQ
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