NPTEL 5G Wireless Standard Design Week 9 Assignment Answers 2024

1. The minimum number of OFDM symbols that should be scheduled for a PDSCH signal so that we can transmit the PDSCH signal with 2 additional single-symbol DMRS of type A.

Note: Use TS38.211 v15.2.0 document.

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2. The maximum number of DMRS ports that can be configured using PDSCH type-2 double-symbol DMRS.

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3. The user is initially allocated a DMRS configuration with no additional DMRS symbols, and the PDSCH symbols are transmitted with a code rate of R1. Now, if the DMRS configuration is changed to include 3 additional DMRS symbols while the rest of the parameters remain the same, the new code rate R2 of the PDSCH symbols will be:

R1 < R2
R1 = R2
R1 > R2
Cannot be concluded

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4. Which of the following statements are true regarding DMRS?

Note: Refer to section 7.4.1 is TS38.211 v15.2.0

The modulation order of the DMRS symbols will depend on the MCS index.
The DMRS sequence will depend on both slot number and OFDM symbol location.
Type B is more suitable for URLLC applications.
The orthogonality of DMRS symbols is present only acorss frequncy domain.

Answer :-

5. Calculate the number of RE’s available to transmit the PDSCH data bits (excluding DMRS locations) for the following PDSCH configuration:

DMRS Type: Type-A, Type-1, Single Symbol DMRS
Number of DMRS ports: 1
Number of OFDM symbols : 8
Number of Additional DMRS : 1
Number of CDM groups without data per DMRS symbol : 2
Number of PRB’s allocated : 150

Note: Please refer to section 7.3.1 in 3GPP document Ts38.212 v15.2.0 for information on “CDM Groups Without Data”.

Answer :-

6. In question 5, if the number of CDM groups without data per DMRS symbol is changed to 1 while the rest of the configurations remain unchanged, then the percentage change in the number of REs available to transmit PDSCH data bits is:

Note: Please refer to section 7.3.1 in 3GPP document Ts38.212 v15.2.0 for information on “CDM Groups Without Data”.

0%
10%
16.67%
17%

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7. Consider a scenario where a moving cyclist (UE) is allocated 14 symbols to transmit a PDSCH signal with Type-A single symbol DMRS, with one additional DMRS and l₀=2. Then, which OFDM symbols will have the poorest channel estimate.

0, 13
4, 5
5, 7
6, 7

Answer :-

8. Which of the following statements are true regarding SRS symbols:

gNB can use the SRS signal to calculate the MCS for PUSCH.
SRS can be used to sound a maximum of 2 antenna ports.
Frequency domain multiplexing of different SRS of different UEs is possible.
Hopping can be performed on an SRS signal.

Answer :-

9. Calculate the minimum number of “CDM groups without data” is required to transmit a PDSCH signal using Type-2 double symbol 4 port-DMRS.

Note: Please refer to section 7.3.1 in 3GPP document Ts38.212 v15.2.0 for information on “CDM Groups Without Data”. Also assume that the transform precoding is disabled.