Which of the following drive 5G low latency? (Choose two.)

5G achieves low latency through innovations in both the radio access and core network architecture. A lower Time Transmission Interval (TTI) in the 5G New Radio (NR) interface allows data to be scheduled and transmitted much faster, directly reducing air-interface delay. This is a key feature of the flexible numerology in 5G. Concurrently, Edge Clouds, an implementation of Multi-access Edge Computing (MEC), bring application processing and content closer to the user at the network edge. This drastically cuts down the round-trip time by minimizing data travel distance through the transport and core network. Together, these two mechanisms are fundamental to enabling Ultra-Reliable Low-Latency Communication (URLLC).

A. Support of up to 1 billion of IoT and sensors devices per km2: This describes massive Machine Type Communications (mMTC), a 5G capability focused on high connection density, not the reduction of transmission delay (latency).
C. Higher spectral efficiency: This refers to transmitting more data per unit of spectrum (bits/sec/Hz), which primarily enhances network capacity and peak data rates, not directly reducing latency.

1. Nokia White Paper, "5G New Radio: Powering the 5G era": In the section "Flexible frame structure," the document explains that the 5G NR's flexible design with scalable numerology "allows 5G NR to support very short transmission durations, which is a key requirement for low latency services." This directly supports the role of a lower TTI (shorter transmission duration) in reducing latency.

2. Nokia White Paper, "Edge cloud: The next wave of cloud": This paper states, "By moving compute resources from centralized data centers to the edge of the network... edge cloud can significantly reduce latency and network congestion... This is critical for emerging applications such as industrial automation, augmented reality and connected vehicles." This confirms that Edge Clouds are a primary driver for low latency.

3. Bennis, M., et al. (2018). "A Survey on 5G Networks for URLLC: Communication Technologies and Challenges." IEEE Communications Surveys & Tutorials, 20(4), pp. 3318-3348. DOI: 10.1109/COMST.2018.2857028: This peer-reviewed survey paper identifies key enablers for URLLC. Section III.A, "Latency Reduction in the RAN," explicitly discusses shorter Transmission Time Intervals (TTIs) and mini-slots. Section IV, "Network Slicing and Edge Caching/Computing," details how Multi-access Edge Computing (MEC) is a "key architectural enabler" for reducing end-to-end latency by processing data at the network edge.