How powerful is 5G? Talking about the development and evolution of the new generation of communication technology

Although 5G communication technology has always been one of the hot topics in emerging technologies and industries, how is it different from 4G? And why is it so important to develop it?

The so-called 5G communication does not refer to a specific single technology, but a general term for the 5th Generation Mobile Networks, which is the expectation for the next generation of communication networks after the maturity of 4G communication technology. The standards have not yet been fully determined, but there is a consensus that the 5G system must be able to achieve at least several capabilities, supporting tens of thousands of users with a data transmission rate of more than 10Gbps, large-scale concurrent connection capabilities and sensor network deployment, and should be far better than 4G in terms of coverage, spectrum efficiency and low latency.

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What is wireless communication?

Wireless communication refers to a communication method that uses the characteristics of electromagnetic wave signals that can propagate in free space to exchange information. In modern times, it has experienced explosive growth due to widespread demand. For example, the early first-generation wireless communication system was an analog mobile phone system that began to be used in 1983 and was replaced by 2G digital communication. The 3G GSM system, which is developed and maintained by the Third Generation Partnership Project (3GPP), provides international roaming and higher-quality digital voice call services.

Starting from 4G, the data transmission rate must reach more than 1 Gbps, and even 100 Mbps is required under high-speed movement. In addition to voice, it has also expanded to areas such as video communication and applied to industries such as finance, medical care, education, and transportation. With a wireless network comparable to ADSL speed, it abandons traditional circuit switching and turns to communication composed of interconnection protocols (IP) between networks, and derives the concept of pervasive network. 5G is a new product under this concept.

In fact, wireless communication technology covers a wide range, not only referring to mobile communications for long-distance calls, but also including near-field communication technologies such as Bluetooth and NFC, and various derived communication protocols. The concept of 5G, in addition to being faster and more stable, is to meet different communication needs such as near-field and long-distance.

Characteristics of wireless communication technology

Since wireless communication is transmitted through electromagnetic waves, of course, when describing its performance, physical properties are often mentioned, such as frequency. For example, 2.4 GHz means electromagnetic waves vibrating 2.4 billion times per second, which is considered a very high frequency. The frequency of telephone and telegraph is only about 1,000 Hz, while the millimeter wave (Millimeter Wave) often mentioned when discussing 5G has a frequency of up to 26.5~300 GHz.

Electromagnetic spectrum and its applications

Although there are other technologies that can improve the efficiency of data transmission, in terms of physical properties, the higher the frequency, the faster the data transmission, so the development of wireless communications is basically moving towards higher frequencies. However, from a physical point of view, the higher the frequency of electromagnetic waves, the more directional they are, the more difficult they are to radiate, and they will also attenuate faster and have a shorter transmission distance.

For example, Bluetooth is a short-baud high-frequency technology that uses the ISM band above 2.4 GHz for communication and attempts to enable mobile devices to exchange data over short distances and form a personal area network (PAN). However, NFC uses a frequency of 13.56 MHz, but it is obviously only applicable to very short distances, and the data transmission rate is far inferior to Bluetooth. However, it is simpler and faster, and is more commonly used in the Internet of Things. Therefore, communication technologies may not necessarily replace each other, but are applied in different scenarios.

Not just mmWave

Although communication technology has advanced to the fifth generation in just over 30 years, it is actually not easy at all. Just increasing the frequency of electromagnetic waves that can be used is already a hurdle. Given that the 6 GHz mid- and low-frequency bands are already very crowded, millimeter wave technology has become an unavoidable challenge for major technology companies, including high-frequency path loss, transmission loss, wall penetration and other performance.

Of course, because of this, the research and development of millimeter wave technology has also been carried out in sequence. First of all, of course, we will start with low-frequency millimeter waves, mainly focusing on below 40 GHz, in response to the commercialization process, which is expected to be completed in early 2019. Frequencies above 100 GHz may not appear until 2020. The International Telecommunication Union (ITU) has currently proposed that the most suitable frequencies for 5G are 28, 39 and 73 GHz.

Of course, some companies have greater ambitions. For example, the 5G Modem released by Intel emphasizes that it is universally applicable. It not only supports the most important sub-6 GHz spectrum and millimeter wave bands, but also has ultra-wideband operation, ultra-low latency, aggregated bandwidth and other performance, and supports technologies such as 5G NR. However, it is expected that the first wave of 5G devices to be launched will still rely on LTE technology and OFDM waveforms that have existed since the 4G era.

Beamforming and Massive MIMO

In fact, the 5G system is not just a high-frequency system, but a multi-channel system. High-frequency antennas will be smaller, which means that more antennas can be placed in the same device, and through multiple-input multiple-output (MIMO), the data transmission rate of 5G will be comparable to that of optical fiber, at least ten times that of 4G. Many countries are now planning to divert expired 3G spectrum to 5G development.

For example, China has planned that its 5G system spectrum will use the 4800~5000 MHz and 3300-3600 MHz bands in addition to millimeter waves to comply with the ITU's IMT-2020 work plan. However, overall, the design of 5G millimeter wave chips is completely different from that of 4G. Problems such as metal conductor loss, dielectric loss, radiation loss and heat dissipation of high-frequency circuit components need to be overcome, and the industry currently prefers components made of gallium nitride semiconductor technology.

In addition to materials, beamforming and Massive MIMO have become hot words in 5G technology. Beamforming is a technology that uses sensor arrays to send and receive signals in a directional manner. It extends the signal transmission distance by superimposing the transmitted or received signals in a specific direction. Massive MIMO is a powerful technology that uses multiple beamforming antennas to achieve massive data transmission.

Of course, this is not easy, because the base station has to use Massive MIMO technology not only to face multiple terminals, but these terminals are often in a mobile state, which also means that the estimation of the signal path (Channel Estimation) will be more difficult, and there are also problems such as pilot contamination and complicated precoding. Of course, simplifying and improving MIMO technology is a major challenge to realizing 5G communications.

D2D and Network Slicing

Not only that, 5G's ambition also includes applications in different scenarios, such as D2D communication (Device to Device) based on cellular networks. In fact, 3GPP began to explore D2D communication technology as early as 2013. Its predecessor was various wireless communication technologies that do not rely on infrastructure to achieve terminal-to-terminal communication, such as Bluetooth. But compared with other similar technologies, D2D will be more flexible. It can not only transmit when there is no network infrastructure, but also use nearby devices with network to connect to the network when there is no network.

Of course, in the 5G era, D2D communication will be able to bring higher spectrum utilization and improve user experience by using Proximity Service (ProSe), including various communication modes such as broadcast, multicast, and unicast. It can even be applied to similar Internet of Things (M2M) communications. Of course, it is also much more complex than the traditional cellular network architecture.

In order to include so many services, network slicing has become a key technology for 5G. Simply put, it is to use the software-defined network (SDN) architecture in the physical network to cut and virtualize the network (Network Function Virtualization, NFV). Each virtual network, including equipment, access, transmission and core networks, is logically independent, and other services will not be affected by errors in one virtual network.

It is more flexible than the currently used LTE mobile network architecture to support a variety of services. Generally speaking, 5G network applications can be divided into three fields: mobile broadband, large-scale IoT and critical IoT, to respond to different applications. Therefore, network slicing is more important, and China's ZTE has taken the lead in launching a fairly mature 5GE2E network slicing technology solution.

However, commercialization still needs to start with "non-independent 5G". Based on the 4G network, the quasi-5G model will be developed. Operators can use the existing LTE network to start trial operation and deployment of 5G NR in 2019, and can add 5G radio access carriers in the future to increase applications. In fact, 3GPP completed the standard of non-independent 5G as early as the end of 2017, laying the foundation for large-scale trials and commercial deployment.

5G Application Scenarios

In simple terms, 5G applications can be divided into five levels: large-scale data transmission, mobile user experience, improving enterprise efficiency, creating a digital ecosystem, and 5G infrastructure and services. Huawei Technologies' 5G white paper mentions that there are ten major scenarios for future 5G applications, including cloud graphics computing, Internet of Vehicles, smart manufacturing, smart energy, wireless medical care, smart home entertainment, connected drones, social live broadcast networks, personal AI assistants, and smart cities.

The most dependent on 5G is real-time computer graphics rendering and modeling in the cloud, which means that the equipment requirements for VR and AR will be greatly reduced, and the number of users will be more effectively expanded to make it more popular, and it will occupy a place in various industries. However, the premise is that a large amount of extremely low-latency data transmission can enable users to effectively access high-speed computing servers in the cloud to achieve economies of scale.

It is estimated that the market size of AR and VR will reach US$292 billion by 2025, and will become the main business of mobile service providers. Of course, there are also well-known emerging technologies such as self-driving cars and smart manufacturing that require 5G, but the market potential is still wireless home entertainment, ultra-high-definition 8K video and cloud games will be important battlefields for 5G technology.

However, there are still many obstacles in the deployment of 5G technology, not only technical issues, but also commercial considerations. For example, unlike the previous 4G network, the 5G radio characteristics also make its coverage rate not as good as 4G. More base stations are needed within the same range, which will have more cost considerations for manufacturers.

Therefore, in the 5G era, more infrastructure sharing will bring greater investment benefits. For example, the British government is committed to resolving investment barriers, clarifying the framework for infrastructure sharing, reducing corporate taxes and even directly intervening in policies to ensure that the market has sufficient funds to promote the development of 5G networks. Of course, the 5G policies of various countries are not yet clear and will change according to the final standards and the results of commercial trials.