With the introduction of 4G and 5G, Communication Service Providers need to plan for 2G/3G closure to reuse the spectrum and reduce costs. This white paper provides recommendations on how to prepare for closure in the Circuit Switching and IP Multimedia Subsystem domains. 4G and 5G have enabled CSPs to gain access to new frequency bands and to re-farm the 2G/3G spectrum, allowing it to be used in a more efficient way. This results in more capacity and lower costs for mobile broadband. Energy efficiency and security are also improving as the transition from 2G/3G to 4G/5G is progressing. The transition is expected to continue at a fast pace and many CSPs have already reached a VoLTE penetration exceeding 90 percent where it would be possible to retire both the 2G/3G networks for voice purposes. However, some challenges remain for these CSPs, such as IoT devices and emergency calls from vehicles (eCall) in the European Union (EU), preventing the final closure. Additionally, inbound roaming needs to be considered before closing a CSP’s own 2G/3G network. to gradually replace 2G/3G is a long process, which can take more than 10 years. In addition to the introduction of IMS, the 4G/5G radio network needs to provide sufficient coverage and have voice services enabled and tuned. A sufficient base of VoLTE capable phones is also a prerequisite for replacing 2G/3G for voice services.

By September 2021, China had made substantial progress in deploying 5G base stations across the country. According to reports at that time, China had deployed hundreds of thousands of 5G base stations, covering many cities and urban areas. The Chinese government had set ambitious targets to accelerate 5G network construction and aimed to provide widespread coverage in major cities, transportation hubs, industrial parks, and other strategic areas. It's important to note that the percentage of 5G base stations can vary over time as the deployment progresses. For the most up-to-date information on the current percentage of 5G base stations in China, I would recommend referring to official sources like reports from telecommunications authorities, industry research publications, or contacting the relevant Chinese government agencies or telecommunication companies directly. hinese operators continue to expand their 5G infrastructure across the country and have already installed a total of 2.73 million base stations, state news agency Xinhua reported, citing data from China’s Ministry of Industry and Information Technology. Mainland China is the largest 5G market in the world, accounting for more than 60% of global 5G connections at the end of 2022. With strong takeup of 5G among consumers, the focus of operators is now increasingly shifting to 5G for enterprises. This offers opportunities to grow revenues beyond connectivity in adjacent areas such as cloud services – a segment where operators in China have recently made significant progress,” the GSMA report reads. 5G will overtake 4G in 2024 to become the dominant mobile technology in China, according to the report. “4G and 5G dominance in China means legacy networks are now being phased out. While most users have been migrated to 4G and 5G, legacy networks continue to support various IoT services. However, some estimates suggest that legacy networks could be almost entirely shut down in China by 2025,” the study reads.

The construction of 6G network facilities has already begun for major Chinese telecom companies. Beijing Mobile China Mobile is the first operator to have started researching 6G technology; it has set up a separate exhibition area at this year's Mobile World Congress showcasing its progress in 6G along with several forums debating pertinent topics here. China Telecom and China Unicom were among the major players at the ongoing Mobile World Congress in Shanghai. The event opened with more than 300 Global Mobile manufacturers, operators, and vendors. As of my knowledge cutoff in September 2021, the deployment of 6G networks and the showcasing of 6G capabilities by Chinese mobile operators such as China Mobile, China Telecom, and China Unicom are still in the early stages. However, I can provide a general description of the anticipated capabilities and potential focus areas of 6G networks based on industry trends and expectations. Please note that this information may not reflect the latest developments as of today. 1. Ultra-High-Speed and Low Latency: 6G is expected to deliver significantly faster speeds and lower latency compared to previous generations. It aims to achieve data transfer rates in the terabits per second range and latency as low as a few milliseconds, enabling near-instantaneous communication and immersive applications. 2. Massive Connection Density: 6G networks aim to support an incredibly high number of connected devices per unit area. This capability is crucial for enabling the widespread implementation of Internet of Things (IoT) devices, smart cities, and other applications that require the simultaneous connectivity of a massive number of devices. 3. Extended Spectrum and Frequency Bands: 6G is expected to leverage new, higher frequency ranges beyond the capabilities of 5G networks. These frequency bands, such as the terahertz (THz) band, offer broader bandwidths and enable faster data transmission, but they come with challenges related to signal propagation and coverage. 4. Intelligent and Immersive Experience: 6G is anticipated to enhance user experiences with advanced technologies like augmented reality (AR), virtual reality (VR), holography, and advanced human-computer interaction. This could involve innovations such as ultra-high-definition content streaming, real-time holographic communications, and immersive virtual experiences. 5. AI-Enabled Networks: AI and machine learning are expected to play a significant role in 6G networks, allowing for intelligent network management, resource allocation, and optimization. AI-based technologies can enhance network efficiency, security, and quality of service while enabling new and innovative applications. 6. Green and Sustainable Networks: Energy efficiency and sustainability are likely to be key considerations in 6G networks. Efforts will be made to minimize the environmental impact through advancements in energy-efficient hardware and network optimization techniques. It's import...

British telecom operator Three has announced a 385% year-on-year increase in 5G usage in 2021. This means more usage on the Three network than 3G, which is often used as a backup when 4G isn’t available. Three attributes the explosive growth in 5G usage to the fact that 5G devices are so popular with consumers that it expects 5G to account for 35 percent of data usage by the end of the year. According to the company, the rapid development of 5G has been driven by consumers’ desire for faster connections. It estimates that 5G could save 23 hours of download time a month, allowing people to move on to other tasks. In its latest findings, it said phone calls became more popular over the same period, with a spike in data on people streaming content on Sunday night. Carlo Melis, chief network officer at Three UK, said: “For mobile users in the UK, it’s time for the old to go and the new to come. The development of 5G is unprecedented and it has now surpassed 3G data usage on our network. It’s telling. Ultra-fast connectivity is the future for our customers – sports and entertainment streaming were two of the main drivers of the data surge last year. To keep up with the demand for data, we’re investing over £2 billion in transforming our network and IT infrastructure, 5G is now live in more than 370 places, covering half of the UK’s population.”

6G will perceive your environment Before looking into the future, it is worth looking back. The previous shift to 4G has witnessed a substantial increase in speed. Now, 5G provides better connectivity and extremely fast speeds for many terminal devices. Although 6G will undoubtedly bring higher speeds, a key to 6G is to use these radios to sense the surrounding environment and transmit information. 5G already has preliminary applications in this area. For example, cellular radio signals can be positioned like GPS. In the 6G era, your mobile phone will be able to recognize the terminal devices around you and act as a bridge between the physical world and the digital world. Those beautiful augmented reality demonstrations can be achieved through 6G: when you look at the restaurant, a digital menu will pop up on the glasses screen. Apple has enabled people to use AirTags to track objects through Bluetooth in many of its devices. But TingfangJi said that the 6G experience will be more like radar, allowing more interaction between devices. “You can actually perceive the environment, so it should be stronger!” For 6G, the mobile communication industry is seeking to expand the use of new frequency bands. The dry megahertz-level frequencies currently used by mobile communication network operators can provide users with a large rate, but the network coverage is limited. TingfangJi introduced that they are studying the terahertz spectrum; The next-generation technology can also solve the dilemma that dry megahertz spectrum is now facing-in the case of the best of both worlds, it may provide higher capacity and wider coverage at the same time. “We are going to introduce some basic technologies to overcome this problem. This is what we are doing, which is very exciting.” What is 5G-Advanced? The industry’s research and development of 6G (mainly referring to the vision) has just begun. Now, it is just a collection of ideas and goals. More specific is the prospect of 5G-Advanced, which is an upgraded version of 5G that may appear in the next two and a half years. Although no one knows exactly what it will consist of, researchers at 3GPP (the Telecommunication Standardization Organization established in December 1998) discussed what improvements the industry should focus on. “5G-Advanced provides us with a second opportunity to examine the basic trade-offs within 5G.” TingfangJi said. He added that researchers are working on 50 areas for 5G-Advanced, but may be further narrowed to around 20. Qualcomm has proposed to integrate machine learning into 5G systems and make the network better handle IoT devices. Qualcomm also proposed the use of full-duplex radio — in which both parties can communicate with each other at the same time.

In the initial stage of 5G deployment, in order to save costs and quickly develop services, most operators choose the non-independent networking (NSA) mode. Due to the cost and maturity of the 5G core network, 5G base stations in the NSA mode preferentially access the 4G core network (EPC). Therefore, the Option 3 series (Option 3x) is the first choice for introducing eMBB services in the early stage of 5G. In the architecture diagram of Option 3x in the above figure, the red line represents the control plane (C-Plane), which is used to transmit control signaling. It has the following characteristics: There is a control plane link called S1-MME between the 4G base station and the core network; The 5G base station does not have a control plane link directly to the core network; There is a control plane link called X2-C between the 4G base station and the 5G base station; The 4G base station is connected to the 4G core network as a control plane anchor point and assumes all control plane functions, so it is also called a “master node.” The 5G base station does not undertake the control plane function, and its interaction with the control plane of the core network is completely dependent on 4G, so it is called a “secondary node.” The green line in the figure represents the user plane (U-Plane), which is used to transmit user data. It has the following characteristics: There is a user plane link called X2-U between the 4G base station and the 5G base station; Both 4G base stations and 5G base stations have S1-U user plane links to the core network. In summary, the option 3 series architecture is a dual connection with 4G as the primary node and 5G as the secondary node, so it is also called EN-DC (EUTRA-NR Dual Connection). In such a dual-connection architecture, mobile phones have two paths to reach the core network via 4G or 5G base stations. So, which path should the data take? There are 3 choices: Downlink data starts from the PDCP layer and is sent to the RLC/MAC/PHY layers of 4G and 5G for independent processing. Finally, the mobile phone receives both 4G and 5G data at the same time. The same applies to the uplink, but in the opposite direction. Two channels of data are sent from the mobile phone to the 4G and 5G base stations, and then processed by their respective PHY/MAC/RLC layers, and finally merged at the PDCP layer. As shown in the figure above, for MCG bearers, regardless of whether the PDCP layer is 4G (E-UTRA) or 5G (NR), it will be transferred to the RLC/MAC/PHY layer of the 4G base station for processing, which means that the MCG bearer is based on 4G; Correspondingly, for the SCG bearer, the entire PDCP/RLC/MAC/PHY is processed by the 5G module, which means that the SCG bearer is based on 5G; Finally, for the split bearer, the data is split into two paths from the PDCP layer of 5G NR, and then to the RLC/MAC/PHY layer of 4G and 5G for processing.