Huawei H35-481_V2.0 - HCIP-5G-RAN V2.0 Exam

The functions of SRSs in NR include downlink beamforming weight calculation, obtaining the uplink channel quality, and uplink beam management. Uplink grants are not related to SRSs.

Extended Cyclic Prefix - an overview | ScienceDirect Topics

https://www.sciencedirect.com/topics/engineering/extended-cyclic-prefix

5G NR Numerology - Subcarrier Spcaing (SCS) - Techplayon

http://www.techplayon.com/5g-nr-numerology-subcarrier-spcaing-scs/

Concepts of Orthogonal Frequency Division Multiplexing (OFDM ...

https://rfmw.em.keysight.com/wireless/helpfiles/89600B/WebHelp/Subsystems/wlan-ofdm/content/ofdm_basicprinciplesoverview.htm

The Slot1 on both the BBU5900 and BBU3910 retains the same physical position. Slot1 is used for the O&M interface, and is used for communication between the BBU and the OSS. It supports the SFP/SFP+ optical modules for O&M communication.

The theoretically noise (dBm) over the air interface should be -116 dBm. The noise is calculated by subtracting the noise figure of the receiver from the thermal noise floor, which is determined by the subcarrier spacing and the bandwidth of each Resource Block (RB). In this case, the subcarrier spacing is 30 kHz and the bandwidth of each RB is 360 kHz, so the thermal noise floor is -116 dBm.

The UE inactivity timer on the NR side expiring and the air interface link on the NR side being abnormal, and a UE reporting SCG Failure Info to the eNodeB, can both trigger the MeNB to release the SgNB. Other actions, such as an inter-SgNB cell change or the MeNB detecting an abnormal X2 link, may also lead to SgNB release, but are not the trigger for it.

Extended Cyclic Prefix - an overview | ScienceDirect Topics

https://www.sciencedirect.com/topics/engineering/extended-cyclic-prefix

5G NR Numerology - Subcarrier Spcaing (SCS) - Techplayon

http://www.techplayon.com/5g-nr-numerology-subcarrier-spcaing-scs/

In SA networking, incorrect TAC configurations will cause UE access to fail. This is because the UE must be assigned a specific TAC value in order to be allowed to access the network. If the TAC value is incorrect, the UE will not be able to access the network. Reference: https://www.qualcomm.com/invention/5g/standalone-networking-5g-sa-networks

When the main control board of a gNodeB is replaced, the Equipment Serial Number (ESN) of the gNodeB also changes. The ESN is a unique identifier of the gNodeB that is programmed into the main control board and is used to identify the specific gNodeB in the network. So when the main control board is replaced, the ESN also changes.

the cell-specific reference signal (CRS) that is always sent in LTE cells is not used in NR to reduce interference under light loads and control channel overhead. Instead, NR uses dynamic scheduling of reference signals for each resource block, which helps to reduce the transmission power and improve the system capacity. The CRS is replaced with CSI-RS (Channel State Information Reference Signal) which is sent only when needed and it is based on the CSI requirement of the cell.

The official site for 3GPP specifications is https://www.3gpp.org/specifications . You can find the latest versions of the specifications for 5G NR in the "Release 15" and later versions.

You can refer to the specification 38.211 (Physical channels and modulation) specifically section 7.4 "Cell-specific reference signal (CRS)" and section 7.5 "Channel state information-reference signal (CSI-RS)".

Here is an excerpt from the specification 38.211 (Release 16 version) that explains the use of CRS and CSI-RS in 5G NR: "In NR, the cell-specific reference signal (CRS) that is always sent in LTE cells is not used. Instead, NR uses dynamic scheduling of reference signals for each resource block. This is done to improve system capacity and reduce transmission power. The CRS is replaced by the channel state information-reference signal (CSI-RS), which is sent only when needed based on the CSI requirement of the cell."

According to Huawei official documentation, using the MAE-Deployment (radio network planning data file) method is recommended for modifying the cell bandwidths across the entire network during gNodeB data reconfiguration. This method allows for the efficient and accurate modification of cell bandwidths by using a radio network planning data file to update the configuration of multiple gNodeBs at once.