5G RAN Architecture and Deployment Flashcards

What is the primary purpose of Ericsson's Radio Dot System?

Answer: Delivering indoor 4G/5G coverage in large buildings using distributed small radio units

The Ericsson Radio Dot System is an in-building small cell solution where compact radio dot units connect via standard Ethernet to a central baseband unit for indoor coverage.

In 5G NR, what does 'SSB (Synchronization Signal Block)' enable a UE to do?

Answer: Detect the cell, acquire time/frequency synchronization, and decode the master information block (MIB)

The SSB contains the PSS, SSS, and PBCH, allowing a UE to detect a 5G cell, synchronize its timing and frequency, and read basic system information.

What is the role of the RRC (Radio Resource Control) protocol in Ericsson's 5G RAN?

Answer: Managing UE state (idle/connected/inactive), bearer setup, handover, and system information broadcast

RRC runs in the gNB-CU and controls UE state transitions, connection setup, measurement configuration, handover procedures, and system information broadcasting.

What does PDCP (Packet Data Convergence Protocol) do in Ericsson's 5G RAN stack?

Answer: Performs header compression, ciphering, integrity protection, and in-sequence delivery for data packets

PDCP provides IP header compression (ROHC), encryption, integrity protection, and in-sequence delivery for both control and user plane data in the 5G RAN.

In Ericsson's 5G NR, what is the 'UE Inactive state' introduced to improve network efficiency?

Answer: An intermediate state between Connected and Idle that preserves UE context in the RAN to enable fast re-activation without a full RRC connection setup

The RRC Inactive state (introduced in 5G NR) stores UE context in the last-serving gNB, enabling the UE to resume data activity with minimal signaling overhead compared to a full re-establishment.

What is Ericsson's 'Spectrum Sharing' capability between 4G and 5G called when used on the same physical antenna?

Answer: Antenna-Integrated Radio (AIR) with DSS software

Ericsson's AIR radios with DSS software support running LTE and 5G NR simultaneously on the same antenna and spectrum, maximizing hardware reuse during 5G rollout.