Ubiquitous Wireless Backbone of the Internet
How should mobile communications develop further now that 4G has already taken a big step towards high data rates (mobile broadband)? At first it was of course obvious to increase the data rates even further and at the same time expand the capacities. LTE has allowed more and more data services such as video transmission, but there are bottlenecks in dense urban areas. In rural areas, on the other hand, it had to be ensured that there was mobile broadband at all.
With LTE, another development was already emerging that was taken into consideration: the Internet of Things. A network of devices and sensors. Narrowband IoT was the keyword. A new 5G network had to felicitate corresponding growth. It had to be possible to operate thousands of sensors in a radio cell and it should be possible for these sensors to exchange data with the radio network with very little effort.
And another application was added. Machine control. Let’s take, for example, two vehicles driving on a highway. When they are in (electrical) connection with each other, they can theoretically travel only 1-2 m apart, even at high speeds. What is necessary is that the following vehicle receives the information within milliseconds that the vehicle in front is braking. This is called platooning. If such a connection is to happen over a radio network, it must have very low latency, i.e. the information must be transmitted within milliseconds. In addition, the connection must be “very secure”. A network that allows such connections would enable completely new industries and applications.
IMT 2020
In 2015, at an IMT Conference, it was decided to define or specify the next generation of mobile communications. After IMT 2000 and IMT Advanced, the new specifications were summarized under IMT 2020.
The International Telecommunications Union (ITU-R) has defined three application groups:
- Enhanced Mobile Broadband (eMBB): Improved broadband data traffic with low latencies.
- Massive Machine Type Communication (mMTC): Applications in the Internet of Things. Low battery consumption sporadic access to the network. For example, sensors or meters that are read every now and then.
- Ultra Reliable and Low Latency Communication (URLLC): Very reliable connections with high data volumes and low latency, for example for remote control of machines and systems.
This resulted in specifications:
Of course, as with every new generation of mobile communications, the peak data rates should be increased. A 5G system should enable at least an uplink data rate of 20 Gbit/s for the downlink and 10 Gbit/s for the uplink.
These are theoretical peak values. However, the “realistic” data rate for users should also increase. In 95% of all cases, the user should be guaranteed data rates of 100Mbit/s in the downlink and 50Mbit/s in the uplink. The average traffic per square meter should be 10Mbit/s.
Another feature for improvement was latency. This has already been significantly shortened from 2.5G to 4G. However, in order to enable special applications, such as machine control, the latency of the air interface should be shortened to up to 1 ms.
It should still be possible to enable handover at high speed (500 km/h).
Another criterion for 5G was to increase the number of devices in a cell. The background is devices and not necessarily cell phones that are connected to the network. It should be possible to manage up to a million devices in 1 sq km.
Furthermore, the transmission efficiency should be 30 bit/Hz.
In summary, 5G should have the following features:
- Peak data rate: 20/10 Gbit/s
- Realistic data rate: 100mbit/s for 95% of participants
- Latency: 1ms
- Speed: 500 km/h
- Devices: 1,000,000 / sq km
- Efficiency: 30 bit/Hz
