The International Telecommunication Union (ITU) has grouped the main 5G services for mobile communications in three distinct categories. These categories are classified according to the 5G network requirements and the technical objectives and various types of services they can offer.
Enhanced Mobile Broadband (eMBB): These services will demand much bandwidth and will require high transmission rates to provide excellent coverage and uniform connectivity everywhere. The relevant services offered are HD video, virtual reality services, or augmented services augmented reality.
Ultra Reliable Low Latency Communications (uRLLC): These services not only require a high data transmission speed but also high reliability and low latency. This way, they will cater for monitoring and remote control critical processes in real-time. Examples include industrial control processes, sensor networks, automation of energy distribution, and remote control of critical equipment. This equipment may be used for e-surgery and health services, autonomous driving, handling of heavy vehicles or machinery in general, etc.
Massive Machine Type Communications (mMTC): These types of communication services will provide wide coverage and deep indoor and outdoor penetration for hundreds of thousands of devices per square kilometer. Furthermore, massive Machine Type Communications aim to provide connectivity everywhere but with low hardware and software complexity. This will in turn result in low deployment costs and lower power consumption. Examples of such services include monitoring and automation of buildings, intelligent agriculture, intelligent supply chain (logistics), fleet monitoring and management, intelligent/smart cities implementations, etc.
5G Network Goals
When 4G LTE was first introduced, maximum speeds would reach up to 75Mbps, which was less than a tenth of the speed the industry had set as the highest performance value for technology (1Gbps). Only after the introduction of new supporting devices, with carrier aggregation techniques, 4G LTE technology was able to reach this target 1Gbps speed. Any mobile communication technology introduced may take several years to achieve the desired speed rates. Similarly, 5G will start its operation with a maximum speed output of just a few Gbps, which will gradually increase to the target peak data rate of 20Gbps per user.
High frequencies with large bandwidths have therefore to be used to achieve the desired goals set for 5G networks. The use of higher frequencies will also result in the development of a large number of base stations and a correspondingly large number of antennas. Furthermore, endurance and tolerance in the density of devices are needed. Therefore, cooperation with other technologies such as LTE and WiFi is also essential to provide universal signal coverage.
5G Network Requirements
Some of the main requirements needed for the development of 5G networks are:
Data rates: For the implementation of 5G, there is a need to support large data rates since this is the driving force of the initial 5G use cases. The total data rate refers to the total amount of network data and is typically measured in units of bits/s/area.
Latency: Time lags are one of the most important challenges in the development of 5G networks. Up to now, 4G technology offered delays of the order of 15ms. With the introduction of 5G, delay times are expected to be improved in the order of 1ms.
Compatibility: With the arrival of the new generation of 5G networks, previous-generation networks are still maintained. The new generation’s 5G systems will work harmoniously with previous technologies, mainly with 4G LTE. Incorporating WiFi technology is also crucial for 5G deployment. In addition, the network will be called to serve various device types. At the same time, in the near future, the development of direct communications between machines, D2D Communications (Device-to-device) is expected to take place.
Energy and costs: The exponential increase in network traffic and the number of connected devices make energy efficiency an important factor in network development. Thus, increasing energy efficiency in mobile network communications will reduce the overall cost of investment and 5G operating costs. 5G design requirements specify that energy usage will be reduced to 10% of the current 4G networks. Cloud and virtualization technologies, new efficient hardware antennas will increase energy efficiency. The 5G small cell network architecture and the most efficient grid protocols will also provide considerable opportunities to harness power dissipation and further reduce the overall energy consumption.
Bandwidth and Network Capacity: The bandwidth size is defined according to the frequency range of electrical signals and electronic devices. It may also plainly be defined as the difference between the highest and lowest frequency of the spectrum in use. 5G will be transmitted via electromagnetic waves in a particular higher frequency. In short, higher frequencies mean higher speeds and greater available bandwidth. The radio spectrum is divided into zones, each with its unique characteristics. These characteristics differ according to the specific frequencies used. Existing radio technologies such as 4G networks use mainly frequencies below the 6 GHz band, while 5G aims to use higher frequencies in the millimeter-wave frequency region.
5G Spectrum Areas
Operators and regulators had to cooperate and help the telecom industry achieve the above main goals of 5G network technology. This would mean including the large bandwidth channels for the new 5th generation of networks, especially compared to the existing channel systems. For this reason, there are three spectral regions identified, which are also known especially in Europe as the 5G pioneer bands.
The Band below 1 GHz, e.g., at 700 MHz: This frequency band ensures extended coverage and offers the possibility of an easy transition from the older generation networks.
The 3400-3800 MHz Band (3.4-3.8 GHz): This is the mainstream frequency region for 5G deployment, which provides the new 5G services’ required capacity by developing a joint architecture of macro and small cells.
The 24.25 – 27.5 GHz (26 GHz) band: This frequency range belongs in the millimeter-wave region and offers ultra-high speeds transmission for innovative services. It also allows the development of new models of entrepreneurship and new sectors of the economy.
The use of other frequency bands is also under consideration. Using/re-farming existing spectrum resources, currently used by other generation systems, e.g., 2G, 3G, 4G / LTE, is an option. Furthermore, new frequencies in the millimeter-wave region (26/28 GHz but also 60GHz and over) are also considered.
5G Millimeter-wave frequencies
It may be relatively easy for the Operators to secure a new high-frequency spectrum in the millimeter-wave region since this is mostly a greenfield deployment area. However, high-frequency bands come with some drawbacks, such as lower coverage and low penetration rate.
In the meantime, beamforming technology has been introduced as a measure of overcoming these weaknesses. Beamforming technology is based on a wireless transmission system that determines the most efficient data supply route to a specific user. It also reduces interference for users in the surrounding area. Furthermore, it allows the millimeter frequencies to travel far with less interference than other signals. The more the data of the antenna, the larger the coverage radius.
Another challenge of millimeter-wave communications is the directivity of the signal. This directivity creates a significant challenge in servicing fast-moving mobile terminals since these terminals should be monitored more accurately and continuously by the signal radius.
Despite the above challenges, millimeter-wave bands are going to be the most significant factor where 5G network expansion will be based upon. The largely available bandwidths and high data speeds, together with some advanced techniques to compensate for signal degradation make millimeter-wave frequencies, the prime candidate to support the 5G network requirements.
