H35-481_V2.0 HCIP-5G-RAN V2.0 Exam Questions and Answers

The base station is in a Holdover state when the dock of a base station is locked and the base station fails to obtain clock source signals. Holdover is a state during which the base station uses the last known frequency and time information to maintain synchronization and clock accuracy. According to the Huawei official documentation, "when the clock source is lost, the base station enters the holdover state. In the holdover state, the base station uses the last known frequency and time information to maintain synchronization and clock accuracy. Holdover time is the duration for which the base station can maintain synchronization after the clock source is lost."

After the PA reconfiguration of a 5G base station in SA networking, it is necessary to check whether cell-related alarms are reported, whether the 5G cell services are normal, and whether the PCI on the NR side has taken effect on the NE. These checks are necessary to ensure that the reconfiguration has been successful.

In 5G NR, the random access procedure is used by a UE to establish a connection with the base station. The channels involved in the NR random access of a UE are:

A. PDCCH (Physical Downlink Control Channel): The PDCCH is used by the base station to transmit control information to the UE, such as scheduling assignments and uplink grants.

B. PRACH (Physical Random Access Channel): The PRACH is used by the UE to transmit the random access preamble to the base station.

D. PUCCH (Physical Uplink Control Channel): The PUCCH is used by the UE to transmit control information to the base station, such as uplink scheduling requests and HARQ feedback.

C. PUSCH (Physical Uplink Shared Channel) is not involved in NR random access of a UE, it is a shared channel used to transmit the uplink data and control information.

ATIS 3GPP

https://www.atis.org/wp-content/uploads/3gpp-documents/Rel16/ATIS.3GPP.38.401.V1620.pdf

TS 138 300 - V16.4.0 - 5G; NR; NR and NG-RAN Overall description ...

https://www.etsi.org/deliver/etsi_ts/138300_138399/138300/16.04.00_60/ts_138300v160400p.pdf

3GPP TS 36.300

https://www.3gpp.org/ftp/tsg_ran/WG2_RL2/Specifications/202012_draft_specs_after_RAN_90/Draft_36300-fc0.docx

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.

According to the official 3GPP specification, the DCI of NR does not carry PUSCH power control information. It carries scheduling information for the PUSCH and PDSCH and a PMI report. Reference: https://www.3gpp.org/DynaReport/38-series.htm

The UBBP board is added to the base station when it is reset, and you need to log in to the LMT again in order to access the new UBBP board. The UBBP board is used for configuration, monitoring, and maintenance of the base station.

5G Implementation Guidelines: NSA Option 3 - Future ... - GSMA

https://www.gsma.com/futurenetworks/wiki/5g-implementation-guidelines/

Understanding O-RAN: Architecture, Interfaces, Algorithms, Security ...

https://arxiv.org/pdf/2202.01032

Report on Risks to 5G from Legacy Vulnerabilities and Best ...

https://www.fcc.gov/file/18918/download

According to Huawei's official documentation, when the UBBP (Universal Baseband Processing) board is added, the base station is reset and you need to log in to the LMT (Local Management Terminal) again. The addition of other boards (OUMPT, UPEU, UEIU) may not require a reset and re-login.