Many customers, colleagues and friends are talking about the planned roll-out of 5G networks and services, and wondering what it will mean to the average consumer of mobile services. I think it’s fair to say 5G is reaching the “Peak of Inflated Expectations” in Gartner’s Hype Cycle, with a lot of focus on “cool” use cases such as Autonomous Vehicles, Augmented Reality (AR) and the ubiquitous Internet of Things (IoT).
In reality, 5G is not a single technology, innovation or solution. It’s actually just an umbrella term for the next generation of mobile network technologies, some of which are already quite mature and deployed on existing 4G networks. For example, Narrowband IoT (NB-IoT) has already been standardised as an extension to LTE in 3GPP Release 13.
We can group the key technologies under 5G into 3 areas (nicely visualised in ITU-R M2083):
- Enhanced Mobile Broadband (eMBB)
o Faster broadband speeds (up to 20Gbps)
o Improved latency (e.g. to support AR/VR applications)
o Requires 5G New Radio (5GNR) RAN technologies
- Ultra-Reliable Low Latency (URLL)
o Industrial automation/robotics, tele-surgery, remote haptics
o Connected vehicles
o Requires new 5G core network to be developed
- Massive Machine Type Communications (mMTC)
o Smart cities, sensor networks, wearables, smart meters, etc.; the Internet of Things (IoT)
o Evolving from 4G LTE CAT-M and CAT-NB
In addition to the technology areas listed above, 5G will also significantly expand on some key technology trends that have already emerged within 4G networks:
o Network Function Virtualisation (NFV), where core network and RAN network elements are composed of cloud-based software instances
o Dynamic slicing and orchestration, where virtual network and service instances are created on-demand, and scaled dynamically
- Small cells
o These are evolving to support 5G access methods and spectrum allocations
o As much of the 5G spectrum is less effective indoors, multiple indoor coverage solutions are needed
- Fixed Wireless Access (FWA)
o mmWave (e.g.28GHz) spectrum used for use cases requiring high throughput (10-60Gbps already in trials) with low mobility
5G Network Evolution
To support the technologies required for 5G, the mobile networks are having to adapt and evolve in a number of key areas, specifically the Radio Access Network (RAN) and the Core.
Looking at the changes required to the RAN to support 5G:
- 5G New Radio (5GNR) introduces new spectrum and new interference issues, while simultaneously trying to co-exist with 4G, 3G and 2G nodes
- RAN subsystem architectures are becoming much more complex, through Cloud RAN (cRAN), Virtual RAN (vRAN) and Extensible RAN (xRAN)
- Shared ownership of RAN elements between operators is becoming more common through Multi-Operator RAN (MORAN) and Multi-Operator Core Network (MOCN)
At the same time, the Core network is also becoming more complex to support 5G technologies and services:
- 5G introduces new core elements (e.g. User Plane Function UPF) and a new core architecture (take a look at this Light Reading paper for some more detail).
- Control and User Plane Separation (CUPS), which already exists in some virtualised 4G networks, is now a standard part of the new 5G core architecture
- Network slicing will be common, where multiple virtual network instances exist using a shared physical infrastructure, supporting differing service types on each
QoE Challenges for 5G
The additional complexity of the new 5G Core and RAN networks makes it more difficult (i.e. expensive) to measure QoE. On its own, this might not be such an issue, however 5G technologies are inevitably introducing associated Quality of Experience issues in some key areas:
- Increased inter-cell interference, caused by a very dynamic, mixed population of heterogeneous cells. A 5G network will consist of many more cells of many different sizes, compared to 4G networks. This is known as a HetNet, where Femtocells, Picocells and Microcells are mixed in amongst the more traditional Macro cells to provide improved coverage in dense urban or indoor areas
- Unpredictable coverage and dynamic performance within each cell, due to the more complex RF designs inherent in 5G NR, such as Multiple Input Multiple Output (MIMO). Understanding and predicting the coverage of each cell is now much more difficult, as coverage now depends on the behaviour and location of all other devices in the same cell
- Poor throughout and latency due to congestion at popular locations. Subscriber expectations will be high for 5G, so the “acceptable” thresholds for throughput and latency will be correspondingly higher than those used for 4G. Cast your mind back to when you watched low-res music videos using an original iPhone on a 3G network in 2007; what was once deemed “acceptable” throughput and latency is soon be perceived as “poor”
- Cell capacity (in terms of the numbers of simultaneously connected devices) will be severely challenged when large populations of IoT devices are commissioned. Each cell has a limited set of RAN resources to allocate to Signalling, and but large numbers of IoT devices will need to share these scarce resources with all other devices served by the same cell
For mobile network operators, 5G technologies present a number of key challenges for deploying and managing the network, driven by increased customer demands and expectations. Service demands on the network will increase significantly, with IoT bringing many more simultaneously connected devices and subscriptions. The capacity expectations of subscribers will similarly increase in terms of peak/average bandwidth, lower latency and improved coverage.
5G brings many benefits to consumers and industry, with support for new services and applications, and substantial improvements from 4G. However, these benefits come at the cost of increased complexity for the network operator, and significant QoE challenges.
A QoE “perfect storm” is brewing, and mobile operators are going to find it much more difficult (i.e. expensive) to measure the Quality of Experience due to the increased complexities of the 5G network
My next Ciqual Blog entry will look at different QoE measurement methods, and their effectiveness for 5G.