PDF H35-580_V2.0 Study Guide

According to the 5G NR Physical Layer Specifications, demodulation reference signals (DMRSs) are required for the following channels/signals in the downlink and uplink:

• Downlink Physical Broadcast Channel (DPBCH)
• Downlink Physical Downlink Control Channel (DPDCCH)
• Downlink Physical Shared Channel (DPOSCH)
• Uplink Physical Random Access Channel (PRACH)
• Uplink Physical Uplink Control Channel (PUCCH)
• Uplink Physical Uplink Shared Channel (PUSCH)

According to the Huawei 5G Base Station Product Description, the following boards support CPU usage query:

• UPEU (Universal Power and Environment Interface Unit): It provides power supply and environment monitoring functions for other boards in a subrack. It supports CPU usage query through commands or web pages.
• UMPT (Universal Main Processing and Transmission Unit): It provides main processing and transmission functions for a subrack. It supports CPU usage query through commands or web pages.
• UBBP (Universal Baseband Processing Unit): It provides baseband processing functions for a subrack. It supports CPU usage query through commands or web pages.

The FAN (Fan Unit) does not support CPU usage query because it does not have a CPU.

According to the HCIA-5G V2.0 Exam Outline, in the NSA DC architecture, when a UE moves to a neighboring gNodeB, the SgNB change procedure is triggered, which corresponds to option D.

According to the eCPRI Specification V2, eCPRI links have the following characteristics:

• They require clock synchronization: eCPRI links use Ethernet as the transport layer, which does not provide inherent synchronization. Therefore, eCPRI links require external clock synchronization methods, such as IEEE 1588v2 Precision Time Protocol (PTP) or Synchronous Ethernet (SyncE).
• They are based on the IP mechanism: eCPRI links use IP as the network layer, which provides routing and addressing functions for eCPRI messages. eCPRI links can use either IPv4 or IPv6 protocols.
• They require AAU support: eCPRI links connect between Radio Equipment Control (REC) and Radio Equipment (RE) in a base station. AAU (Active Antenna Unit) is a type of RE that integrates RF and antenna functions in one unit. Therefore, eCPRI links require AAU support to enable flexible functional split options and reduce fronthaul bandwidth requirements.

eCPRI links are not based on the TDM mechanism because they do not use fixed time slots to transmit data. Instead, they use variable-length packets to transmit data according to different service requirements.