5G PT-RS frequency density and time density in FR2

5G NR
21

It should give… I have not tried on live network.

22

To be clear, I am simulating PDSCH throughput in MATLAB using 5G toolbox.
Because I am doing a thesis of it.
I have to claim that which one is the better way to perform and avoid any kind of noise and interference such as ISI, ICI, and phase noise.

23

Okay, I think it depends on MCS value also so need to check other parameters also.

24

Here is the point, I will use MCS Index From MCS Table 1 (TS38.214):

  • MCS 7 (QPSK),
  • MCS 16 (16QAM),
  • MCS 22 (64QAM),

From MCS Table 2 (TS38.214):

  • MCS 27 (256QAM)

Those MCS I will use it for my thesis.
PT-RS is only operated in FR2 range.

25

OK, use it and share your result after simulation.

26

With Lptrs = 1 and Kptrs = 2?
And try with Lptrs = 2 and Kptrs =2 also?

27

Yes so with lptrs 1 you should get good output compared to lptrs 2

28

I think. But, I will try both and I will shared to conclude.

29

For more details on PTRS and it’s mapping, please checkout

30

Hello Experts.

For PTRS.

I came across following statement - “Due to the properties of phase noise, PTRS can have low density in the frequency domain but high density in the time domain.”

  • My breakdown of this scenario - is linking phase noise to spectral regrowth - then to frequency domain graph (of phase noise- spectral regrowth - creating Inter carrier interference) and this ICI will cause ISI in time domain too, then why not PTRS have high dense in frequency domain ?

I am a bit confused while trying to understand why high density in the time domain ? Any basic clarification or Guidance will be helpful. Thanks

31

Why do we use PTRS?

  • Because at higher frequencies, we may have a phase error at transmitter or receiver.
  • Phase might be changing slowly with time.
  • The effect will mostly be the same for full bandwidth.

So what do we do?

  • We densely put the reference signal over time but not so densely in frequency.
  • We track the changing phase using the densely mapped reference signal (ptrs)

For the DMRS symbols, dmrs can do the phase estimation.

But DMRS has higher overhead.

So we can’t add more dmrs symbols to the track phase.

We better use reference signal that has lower overhead and highly densely over time.

32

Thank you for linking it to phase error, which is the same effect for full BW.

And also how we can save overhead using PTRS.

33

PTRS has very low overhead than DMRS.

34

Correct.

And PTRS is only used for mmwave frequencies or can we make use in sub6 also?

Is there any mandate in specs that PTRS should be for mmwave freq. only?

35

I think there is no mandate as per 3GPP.

We can use it for both FR1 & FR2.

But as the chances of phase error increased with higher frequencies that’s why it is more suitable for FR2.

36

Yes. True.