## 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.

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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”.

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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 l_{0}=2. Then, which OFDM symbols will have the poorest channel estimate.

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

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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.

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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.

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10. The minimum number of OFDM symbols required to transmit a PDSCH signal with Type-B double-symbol DMRS configuration is:

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