Technology Behind 5G

Spectrum and Frequencies

The radio frequency spectrum is divided into bands that are allocated for various uses, including mobile telecommunications. 5G technology utilises multiple frequency bands to optimise performance across different scenarios and environments.

Low-Band Spectrum

Low-band frequencies typically range from 600 MHz to 1 GHz. These frequencies offer excellent coverage and can penetrate buildings effectively, making them suitable for providing widespread 5G coverage across large geographical areas. However, low-band spectrum has limited capacity and provides data speeds that are only modestly faster than 4G networks.

Mid-Band Spectrum

Mid-band frequencies typically range from 1 GHz to 6 GHz. This spectrum represents a balance between coverage and capacity, offering significantly faster speeds than low-band while maintaining reasonable coverage characteristics. Mid-band spectrum is considered the "sweet spot" for 5G deployment as it provides a good compromise between performance and coverage.

High-Band Spectrum (mmWave)

High-band or millimetre wave (mmWave) spectrum ranges from 24 GHz to 40 GHz and beyond. These extremely high frequencies offer the highest data speeds and lowest latency, but have very limited range and poor building penetration capabilities. mmWave deployment requires dense infrastructure with many small cells to provide practical coverage.

Spectrum Allocation in Australia

The Australian Communications and Media Authority (ACMA) manages spectrum allocation in Australia. Various frequency bands have been allocated for 5G use through auction processes and government assignments. The allocation of spectrum involves balancing the needs of different services and ensuring efficient use of this limited resource.

Network Infrastructure

5G networks require sophisticated infrastructure to deliver their enhanced capabilities. This infrastructure has evolved from previous generations to support higher frequencies, greater capacity, and more advanced network features.

Radio Access Network (RAN)

The Radio Access Network consists of the equipment that connects mobile devices to the core network. 5G RAN includes several key components:

• Base Stations (gNodeB): 5G base stations, known as gNodeBs, are the primary transmission points for 5G signals. They replace the eNodeBs used in 4G networks and support more advanced antenna technologies and signal processing capabilities.
• Antenna Arrays: 5G utilises advanced antenna arrays with multiple elements to support beamforming and MIMO (Multiple Input Multiple Output) technologies. These arrays enable more efficient signal transmission and reception.
• Small Cells: Small cell installations complement traditional macro cell towers by providing additional capacity and coverage in specific locations. These compact cells are essential for mmWave deployment and high-density areas.

Core Network

The 5G core network has been completely redesigned to support new capabilities and requirements:

• Network Slicing: The ability to create multiple virtual networks on a shared physical infrastructure, each optimised for different use cases such as enhanced mobile broadband, massive IoT, or ultra-reliable low-latency communications.
• Software-Defined Networking (SDN): Network functions are implemented in software rather than dedicated hardware, allowing greater flexibility and faster deployment of new services.
• Cloud-Native Architecture: Core network functions are deployed in cloud environments, enabling scalability and efficient resource utilisation.
• Edge Computing: Computing resources are distributed closer to the network edge to reduce latency and enable new applications that require real-time processing.

Backhaul and Transport

The backhaul network connects base stations to the core network and requires substantial capacity to support 5G's high-speed capabilities:

• Fibre Optic Cables: High-capacity fibre connections form the backbone of 5G backhaul, providing the bandwidth necessary to support high-speed services.
• Millimetre Wave Backhaul: In some cases, mmWave frequencies are used for wireless backhaul where fibre deployment is impractical.
• Satellite Links: Satellite connections may be used for backhaul in remote areas where other options are unavailable.

Latency and Speed Concepts

Understanding the performance characteristics of 5G requires familiarity with key technical concepts that describe how data is transmitted and processed through the network.

Latency

Latency refers to the time delay between a request being sent and a response being received. In mobile networks, latency is measured in milliseconds (ms) and is affected by various factors:

• Propagation Delay: The time for signals to travel between the device and the network infrastructure, limited by the speed of light.
• Processing Delay: Time required for network equipment to process and route data packets.
• Queueing Delay:
• Time packets spend waiting in queues when network congestion occurs.
• Transmission Delay: Time required to push packet bits onto the network link, dependent on data rate.

5G Latency Improvements

5G networks achieve significantly lower latency than previous generations through several technical improvements:

• Shorter Transmission Time Intervals (TTI): Reduced time between scheduling and data transmission.
• Advanced Frame Structure: Optimised frame design reduces processing delays.
• Edge Computing: Processing data closer to users reduces round-trip times.
• Network Slicing: Dedicated slices can be configured for ultra-low-latency applications.

Data Speed Concepts

Data speed in mobile networks is measured in bits per second (bps), typically expressed in megabits per second (Mbps) or gigabits per second (Gbps). Several factors affect achievable speeds:

• Bandwidth: The amount of spectrum available for data transmission. More bandwidth allows higher potential speeds.
• Signal Quality: Better signal quality enables more efficient use of available bandwidth.
• Network Congestion: Shared resources mean speeds decrease when many users are competing for capacity.
• Device Capabilities: The device's modem and antenna technology limits maximum achievable speeds.
• Distance from Tower: Greater distances generally result in lower speeds due to signal degradation.

Difference Between 4G and 5G

5G represents a significant evolution from 4G technology, offering substantial improvements across multiple dimensions. The following comparison highlights key differences between these generations.

Technical Architecture Differences

• Core Network: 5G uses a completely new core architecture that supports network slicing, cloud-native deployment, and edge computing. 4G uses an evolved packet core designed for traditional mobile broadband services.
• Radio Technology: 5G incorporates advanced antenna technologies including massive MIMO and beamforming, enabling more efficient spectrum utilisation. 4G uses less sophisticated antenna systems.
• Spectrum Usage: 5G utilises a much wider range of frequencies, including low-band, mid-band, and high-band (mmWave) spectrum. 4G primarily uses frequencies below 6 GHz.
• Service Types: 5G is designed to support three primary service types: Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communications (URLLC), and Massive Machine Type Communications (mMTC). 4G was primarily focused on mobile broadband.

5G Service Types