ETCP 5G RAN Architecture and Deployment 1 — Questions and Answers
Question 1: In Ericsson's 5G NR RAN, what does 'gNB' stand for?
- Generalized Node B
- Next-Generation Node B (Correct answer)
- Gateway Node Base
- Grid Node Broadband
Correct answer: Next-Generation Node B
gNB (Next-Generation Node B) is the 5G NR base station, equivalent to the eNB in 4G LTE, that provides the radio access function in a 5G network.
Question 2: What is the functional split in Ericsson's CU/DU architecture for 5G?
- CU handles higher-layer protocols (PDCP, RRC); DU handles lower-layer protocols (RLC, MAC, PHY) (Correct answer)
- CU manages physical antenna beamforming; DU handles IP routing
- CU provides power to the RU; DU manages transport backhaul
- CU is the outdoor unit; DU is the indoor baseband unit
Correct answer: CU handles higher-layer protocols (PDCP, RRC); DU handles lower-layer protocols (RLC, MAC, PHY)
The CU (Central Unit) hosts higher-layer protocols (RRC, PDCP) for multiple DUs, while the DU (Distributed Unit) handles real-time lower-layer processing (RLC, MAC, PHY) close to the antenna.
Question 3: Which Ericsson 5G product integrates the baseband and radio into a single outdoor unit?
- Ericsson Radio Dot
- Ericsson Integrated Access and Backhaul (IAB) node
- Ericsson AIR (Active Intelligent Radio) series (Correct answer)
- Ericsson MINI-LINK PT
Correct answer: Ericsson AIR (Active Intelligent Radio) series
Ericsson's AIR (Active Intelligent Radio) units integrate massive MIMO antenna arrays with radio transceivers and may include baseband processing in a compact outdoor form factor.
Question 4: What is Massive MIMO in the context of Ericsson's 5G radio deployments?
- A technique using a single large antenna element for wide coverage
- A system with a large number of antenna elements enabling multi-user spatial multiplexing and beamforming (Correct answer)
- A modulation scheme for millimeter-wave frequencies
- A frequency aggregation method for carrier aggregation
Correct answer: A system with a large number of antenna elements enabling multi-user spatial multiplexing and beamforming
Massive MIMO uses dozens to hundreds of antenna elements to form precise beams toward multiple users simultaneously, dramatically increasing spectral efficiency.
Question 5: In Ericsson's 5G RAN, what is the purpose of the F1 interface?
- Connects the gNB to the 5GC AMF
- Connects the CU to the DU within a disaggregated gNB (Correct answer)
- Links two gNBs for X2-equivalent communication
- Provides timing reference to the RU
Correct answer: Connects the CU to the DU within a disaggregated gNB
The F1 interface (F1-C for control, F1-U for user plane) is the 3GPP-defined interface between the gNB-CU and gNB-DU in a split RAN architecture.
Question 6: What does 'beamforming' enable in Ericsson's 5G Massive MIMO radios?
- Automatic frequency hopping across bands
- Directing radio energy toward specific users to improve signal quality and reduce interference (Correct answer)
- Compressing baseband data before transmission
- Encrypting over-the-air radio frames
Correct answer: Directing radio energy toward specific users to improve signal quality and reduce interference
Beamforming steers narrow radio beams toward individual or groups of users, increasing received signal strength and reducing interference to other users.
ETCP 5G RAN Architecture and Deployment 1
In Ericsson's 5G NR RAN, what does 'gNB' stand for?