What is Logical Antenna Port (vs Physical Port)?

What is logical antenna port in LTE?
And in 5G NR?

Antenna ports do not correspond to physical antennas, but rather are logical entities distinguished by their reference signal sequences.

Multiple antenna port signals can be transmitted on a single transmit antenna (C-RS port 0 and UE-RS port 5, for example).

Correspondingly, a single antenna port can be spread across multiple transmit antennas (UE-RS port 5, for example).

Thanks for help. :wink:

Hi…an antenna port is generally used as a generic term for signal transmission under identical channel conditions. For each LTE operating mode in the downlink direction for which an independent channel is assumed (e.g. SISO vs. MIMO), a separate logical antenna port is defined.

How do we know which antenna port to use in receiver to compute channel coefficients?

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Antenna port is in the 3GPP specifications an abstract concept that is a logical entity rather than a physical antenna.

Each antenna port is associated with a specific set of reference signals.

5G NR contains a different type of reference signals, like DMRS for demodulation purpose & CSI-RS for channel status reporting.

An antenna port is an indication of the type of reference signal that conveyed over the radio channel.


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Hi Experts.

What is difference between Antenna Logical and Physical Ports?

Logical ports for smart antennas like p7, p8 for tm8.

You can say it virtual ports as well.

Physical antenna what i understood which are non smart ie not for beamforming.

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Reference signals are assigned to Logical antenna ports and each logical antenna ports are having unique postioning of reference signals.

Whereas physical antenna ports are number of RF output ports at RRH/RRU end.

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Now, what is the difference between Layer, Logical port, Antenna Ports and Physical Antenas?
How are they interconnected?

You have to read 3gpp for this.
There are antenna ports 1000 then 3000.
Also csi-rsports are involved.

Keep in mind these: there can be 4 layers for one UE and 4, 8, 16 or 32 csi-rs ports and up to 384 antenna elements.

Thanks. Which 3gpp?

There are several of them, but start with PHY layer first:

You can also check 3gpp guru:

  • Layer: on which codeword transfer.
  • Logical port: with smart antennas mainly introduced with beamforming concept with tm7 in LTE.
  • Antenna port: with passive antenna where we have 2,4 ports antenna.