H35-580_V2.0 HCIA-5G-RNP&RNO V2.0 Question and Answers

According to the 5G EN-DC Architecture and Interfaces, there are two methods that can be used to support X2 interconnection between an eNodeB and a gNodeB in NSA networking:

• Interconnection through CI interfaces on the UMPT boards in different subracks: The UMPT is a universal main processing and transmission unit that provides main processing and transmission functions for a subrack. The UMPT has two CI interfaces that can be used for X2 interconnection with other base stations. The CI interfaces support CPRI, OBSAI, and eCPRI protocols and can use optical fibers or electrical cables for transmission. The CI interfaces can be configured as master or slave interfaces depending on the network topology.
• IPRAN interconnection between subracks: IPRAN is an IP-based radio access network that uses IP transport technologies to carry base station traffic over Ethernet or MPLS networks. IPRAN can support X2 interconnection betweendifferent base stations by using IP routers or switches. IPRAN can provide flexible networking, high bandwidth, low latency, and high reliability for X2 interconnection.

The other two methods are not valid for X2 interconnection between an eNodeB and a gNodeB:

• Interconnection via backplane in a subrack: This method is only applicable for X2 interconnection between two eNodeBs or two gNodeBs that are installed in the same subrack. The backplane is the internal bus that connects different boards within a subrack. The backplane supports CPRI, OBSAI, and eCPRI protocols and can provide high-speed data transmission between boards.
• Interconnection through HEI interfaces on the UBBP boards in different subracks: This method is not supported by Huawei base stations. The HEI interface is a high-speed Ethernet interface that is used for data transmission between base stations and core networks or transport networks. The HEI interface supports S1, Xn, F1, E1, and N2 protocols and can use optical fibers or electrical cables for transmission. The HEI interface cannot be used for X2 interconnection between base stations.

Therefore, the correct answer is A and D.

According to the China’s Approach to Military 5G Networks and Related Military Applications, CU-DU Split of a base station means that the base station’s control plane functions (CU) and user plane functions (DU) are separated, which can improve network flexibility and scalability.

In order to achieve ideal coverage, there should be a clearance zone around an antenna of at least d, where d is the Fraunhofer or Rayleigh distance at which the near/far-field transition zone exists 17. This distance depends on the largest dimension of the antenna, D, and the operating wavelength, \uF06C. Ideally, D should be at least a half of a wavelength, which gives a minimum clearance zone of a half-wavelength. For example, at 2.4 GHz, the wavelength is about 0.125 m, so the minimum clearance zone is about 0.0625 m. However, in practical situations, this clearance zone is often compromised and the effects must be determined through simulation or empirical measurement 18. A general guideline is to have a clearance zone of 5-10 m around an antenna to avoid significant degradation of performance 19. Therefore, the best answer is C.

According to the HCIA-5G V2.0 Exam Outline, base station receive diversity gain is a factor that affects uplink coverage, not downlink coverage. Downlink coverage is affected by factors such as downlink path loss, downlink transmit power, and antenna gain, which correspond to options B, C, and D.

According to the Huawei’s Latest AAU Products, Huawei’s AAUs have an operating voltage of -48 V DC and support LTE-NR dual-mode on some frequency bands, such as C-band and sub-3 GHz bands. The article also states that Huawei’s new-generation 64T64R AAUs provide higher coverage gains than conventional 32T32R AAUs by using ELAA (extremely large antenna array) technology. Huawei’s AAUs do not support GSM-NR dual-mode on any frequency band, as GSM is not a compatible RAT with NR.

The link budget parameters that may differ depending on use in either densely populated urban areas or rural areas are area coverage rate, shadow fading margin, and penetration loss. The area coverage rate is the percentage of area within a cell that can receive a signal above a certain threshold. In densely populated urban areas, the area coverage rate may be lower than in rural areas due to more interference and obstacles 13. The shadow fading margin is an additional margin added to the link budget to account for the variation of signal strength due to obstacles in the propagation path. In densely populated urban areas, there may be more buildings and structures that cause shadow fading than in rural areas, so a larger shadow fading margin may be needed 14. The penetration loss is the loss of signal strength when it passes through walls or windows into buildings. In densely populated urban areas, there may be more indoor users than in rural areas, so a larger penetration loss may be considered 15. The antenna gain is not a parameter that depends on use in either densely populated urban areas or rural areas. It is a parameter that depends on the antenna design and configuration, which are usually fixed for a given system 16.

 According to the LTE-NR tight-interworking and the first steps to 5G, in a Huawei base station, QCI2 can only be configured as an MCG (Master Cell Group) bearer. QCI2 is a voice bearer that requires low latency and high reliability. Therefore, it cannot be configured as an SCG (Secondary Cell Group) bearer or a split bearer that may introduce additional delay or packet loss. QCI6, QCI9, and QQ1 can be configured as either MCG bearers, SCG bearers, or split bearers depending on the service requirements and network conditions.

According to the HCIA-5G - Huawei Enterprise Support Community, reflection in a large amount of water and signals traveling far along a street due to the waveguide effect are common causes of overshoot coverage, which correspond to options A and C.

Massive MIMO is a technology that uses a large number of antennas at the base station to serve multiple users simultaneously, thereby increasing the spectral efficiency and capacity of the wireless system 1. Massive MIMO is especially suitable for application scenarios where there is high user density and high traffic demand, such as large venues, high-rise buildings, and densely populated urban areas 2. Suburban areas with light traffic do not have such high requirements for spectral efficiency and capacity, and therefore are not a typical application scenario of massive MIMO.

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.

A site survey is an inspection of an area where work is proposed, to gather information for a design or an estimate to complete the initial tasks required for an outdoor activity 1. A site survey can cover various aspects, such as antenna installation space, equipment room space and load bearing capacity, site location, and other environmental factors 2. However, a site survey does not cover the models of hardware boards on base stations, as this information is not related to the physical characteristics of the site. The models of hardware boards on base stations are determined by the network design and configuration, which are based on the network requirements and specifications 3. Therefore, the correct answer is C.

The Rayce ray tracing model is a propagation model that computes propagation paths using 3-D environment geometry 3. It is based on the shooting and bouncing rays (SBR) method, which launches rays from the transmitter and traces their reflections and diffractions until they reach the receiver or are attenuated below a threshold 4. The Rayce ray tracing model offers more accurate path searching, reflection, and diffraction energy calculation for electromagnetic wave propagation than other models, such as empirical models or deterministic models 5. It also offers higher level prediction accuracy, especially for massive MIMO systems that use beamforming techniques 6. The Rayce ray tracing model is not applicable only to C-band, but also to mmWave and other frequency bands 7.

According to the HCIA-5G - Huawei Enterprise Support Community, overlapping coverage is likely to occur in areas such as inside a tunnel, crossroads in dense urban areas, and high-rise buildings, which correspond to options A, B, and C. These areas have complex propagation environments and multiple paths for signals to reach the UE. Around areas with water, overlapping coverage is unlikely to occur because water can reflect signals and reduce interference from other cells, which corresponds to option D.

According to the Troubleshooting Guide for Huawei 5G Base Stations, the possible causes of SCTP link disconnection over the N2 interface are as follows:

• Routes are not configured: If the routes between the base station and the core network are not configured correctly, the SCTP link cannot be established or may be disconnected.
• PLMN configurations are incorrect: If the PLMN configurations on the base station and the core network do not match, the SCTP link cannot be established or may be disconnected.
• Physical ports are faulty: If the physical ports on the base station or the core network are faulty, such as damaged cables, loose connectors, or port errors, the SCTP link cannot be established or may be disconnected.
• The SCTP port configuration is incorrect: If the SCTP port configuration on the base station or the core network is incorrect, such as using a reserved port number or a conflicting port number, the SCTP link cannot be established or may be disconnected.