Two of the IMT-2020 specification’s targets seem aggressive: one million devices per square km and 100 Mbps available across the coverage area to all users. As already seen with 2G and 3G, it is reasonable to expect the 5G standard to be used for more than 20 years. So the aggressive targets are intended to support future applications that may be as yet unknown, allowing the 5G networks to scale up as new industries or new groups of customers emerge. But what seems likely in the near-term, say the first five years of 5G operations?
One case sometimes offered as an example with the high-density requirement is a big sporting event. This may involve 50,000 to 100,000 people in a stadium with a large number of them simultaneously trying to use their smartphones for sending or receiving videos or other communications. Of course, consumers would expect to use their phones at such events as part of their regular monthly fee. So the stadium example doesn’t really give the carriers a new business-case for building 5G networks. (It may give the stadium builders and owners a case for installing WiFi and other premises gear, which can be paid back over multiple seasons by ticket purchases.)
The high-density specification covers IoT, meaning that the connected devices in a square km of developed urban areas may include traffic lights, street lights, building controls, surveillance cameras, parking metres, utility metres, and other sensors, as well as smartphones, tablets, “wearables,” and other consumer devices. Many of these devices, such as utility metres, do not need low latency or high bit rates. Such applications, however, can benefit from 5G’s low-power specification, as well as the ability of 5G to support diverse applications in the same area, using spectrum slicing and other ways of partitioning a cell’s overall capacity.
IoT applications are expected to drive the number of mobile subscriptions, including all connected devices above ten billion within the next five years. Some communications companies, including Cisco and Vodafone, have estimated that the number of IoT connections using cellular networks was about one billion in 2017. Industries that already have a high number of IoT connections include:
When counting IoT devices as possible 5G applications, however, there can be some confusion with the large statistics. Not all connected devices use mobile-cellular networks. Many devices are on other wireless networks, some of which are referred to as “low-power wide-area” (LWPA) technologies. Examples of LWPA standards include Lo-Ra, NB-IoT, and SigFox. In the future, some IoT connected devices will use other cellular technologies, such as 3G or 4G, rather than 5G, possibly because 5G was not available when the equipment was set up.
One firm specializing in technology analysis, Gartner, estimated that the number of connected things worldwide exceeded eight billion in 2017. Most of these are not on cellular networks. Gartner says this total will grow to 20 billion by 2020. Ericsson has forecast the world to have 20 billion connected things in 2023, with 3.5 billion using cellular connections.
Another source of confusion is that some of these large IoT estimates and forecasts include multiple devices connected to the Internet through a single gateway device, having a single IP address. One example is a home WiFi router, which may connect security sensors, door locks, thermostats, cameras, smart speakers, TVs, PCs, and other devices to the Internet. Also, a single cellular account, based on one SIM (subscriber interface module) residing in a cell phone, may have multiple devices, such as a smart watch or headphones, connected to the phone via Bluetooth, a short-distance wireless standard.
Although IoT systems may account for billions of devices within five years, they will account for only a small percentage of mobile network traffic. The major contributor to the traffic load will be video services, driven mainly by consumers sending or receiving videos from smart-phones.
Cisco has been assessing and forecasting mobile traffic with an annual report since 2012. The data shows that the amount of traffic sent or received by smart-phones increased with a CAGR of 89% from 2012 to 2017. The amount of traffic associated with video communications increased with a CAGR of 74% from 2012 to 2017. Cisco expects the growth in video and smart-phone traffic to decelerate in the next five years but continue to be the main drivers. Traffic associated with M2M or IoT applications will have rapid growth in the next five years, but with lower quantities, as measured in Bytes transmitted and received per month by the devices.