Enlightenment on using Smallcell to solve deep network coverage in the post-5G era

1. Current status of network coverage in the post-5G era

2019 is the first year of 5G commercialization in China, and 5G has brought great convenience to people's lives. The latest data from the Ministry of Industry and Information Technology shows that by the end of September 2023, my country has built and opened 3.189 million 5G base stations, covering all prefecture-level cities and county towns, with 22.6 5G base stations per 10,000 people, accounting for more than 60% of the world's total base stations. In the more than four years of 5G commercialization, 5G applications have covered many areas of life such as transportation and medical care. 5G communications play a huge role in the live broadcast of the 2022 Beijing Winter Olympics, the prevention and control of new coronary pneumonia, telemedicine, autonomous driving of Internet of Vehicles, and smart venues for the 2023 Asian Games in Hangzhou.

In the early stage of 5G network construction, the focus of network coverage was on breadth. With the growth of the number of users, the traffic in hot spots will surge during peak hours, resulting in a decline in user experience. Entering the post-5G communication era, people have put forward higher requirements for the transmission speed of wireless communications. With the deployment of 5G high-frequency bands, 5G macro station signal transmission has a greater path loss, and the obstruction of buildings has made indoor 5G signal coverage seriously insufficient. As a result, the current dilemma has emerged: first, the high frequency band of 5G makes it difficult for outdoor macro station signals to reach indoors, and second, more and more business and traffic demands occur indoors in the 5G tob and toc era. The cost of building a station is too high to simply increase the coverage of macro stations. In response to the above dilemma, small base stations have become a "weapon" to solve the pain points of 5G networks and provide a new solution for achieving 5G deep coverage. The networking mode of "macro base stations as the main and small base stations as the auxiliary" is the main network deployment method in the post-5G era.

2. Introduction and application prospects of Smallell

Smallcell originated from Femtocell. International standard organizations such as the Smallcell Forum and 3GPP have conducted long-term research on femtocell and carried out a lot of work on technical standards. As Femtocell has moved from home base station applications to various application scenarios such as enterprises and indoor hot spots, its name has been changed to Smallcell. Smallcell inherits the basic standards of Femtocell and expands various application scenarios and new requirements to form a complete Smallcell technical standard. There are two main definitions of Smallcell: First, in the 3GPP standard, it is defined as a low-power device node with lower transmission power than macro base stations, aiming to solve the capacity improvement of indoor and outdoor hot spot scenarios and cope with the blowout growth of data traffic. Second, the Smallcell Forum defines smallcell as various low-transmission power, small-range coverage wireless access devices deployed by operators working in the licensed frequency band, helping to improve the coverage and capacity of macro cellular networks, and becoming a beneficial supplement for operators to efficiently use wireless spectrum resources and data offload. The device form and application scenario of Smallcell are shown in Figure 1.

Figure 1 Smallcell device form and application scenario

As shown in Figure 1, the large-scale deployment of Smallcell (including femtocell\microcell\picocell) can solve the problems of indoor coverage, hotspot coverage, and deep coverage of mobile communication networks, make up for the shortcomings of macro cells, improve spectrum efficiency, increase network capacity, and better meet the development needs of future mobile communication services and improve user experience. In general, the application prospects of Smallcell technology are very broad, and it can provide better solutions for wireless communications in various fields and promote the process of digitalization and intelligence.

In 2022, professional research organization ABI Research predicts that when Massive MIMO macro base stations cannot meet 5G capacity requirements, outdoor small cell deployment will begin to increase around 2025. Fei Liu, an industry analyst at ABI Research and 5G mobile network infrastructure, pointed out that 5G small base stations complement macro base stations, increase network capacity, and expand coverage in densely populated areas where signals are weak or unavailable. As an effective supplement to 5G macro base stations, 5G small cell applications are becoming more and more common. According to the Smallcell Forum (SCF) in the "SCF market status report July 2020" report, the number of small base stations will maintain an average annual growth of 13% from 2.7 million to 6.3 million from 2019 to 2026, with a cumulative deployment of 38.3 million. Among them, telecom operators' small base station deployment in urban environments has increased by an average of 24% per year, and 80% are concentrated in enterprises, industries and schools indoors. Small base stations deployed by enterprises will grow at an average annual rate of 9%, accounting for 68% of the total; small base stations deployed in rural and remote areas will maintain an average annual growth rate of 19%, mainly serving industrial and IoT companies, and 957,000 will be installed by 2026.

Figure 2 Smallcell station growth trend

Smallcell deployment scenarios

Smallcell deployment scenarios are very diverse, helping operators meet users' needs for high-speed communications anytime and anywhere. Some typical application scenarios are as follows:

a) Indoor coverage

Smallcells can provide better wireless coverage and capacity in indoor places such as large shopping malls, hotels, and office buildings, improving user experience.

b) City streets

Smallcells can provide better wireless coverage and capacity in densely populated areas such as city streets and squares to meet users' communication needs.

c) Rural and remote areas

Smallcells can provide better wireless coverage and capacity in rural and remote areas, make up for the coverage blind spots of traditional base stations, and improve the quality of communication services.

d) Internet of Things (IoT)

Smallcells can be used to connect IoT devices, providing more stable and efficient communication support for areas such as smart cities and smart homes.

e) Transportation

Smallcells can provide better wireless coverage and capacity in transportation hubs such as subways, train stations, and airports, improving user experience.

f) Industrial sector

Smallcells can provide better wireless coverage and capacity in industrial parks, factories and other places, and support applications such as the Industrial Internet of Things.

g) Medical field

Smallcells can provide better wireless coverage and capacity in hospitals, clinics and other places, supporting applications such as the medical Internet of Things.

4. Smallcell security risks

a) Physical security risks

Smallcells are usually installed in easily accessible locations outdoors or indoors, making them vulnerable to vandalism, theft or destruction. Unauthorized personnel may interfere with or damage the equipment, resulting in interruption of communication services.

b) Data security risks

Smallcells may store some sensitive communication data, which, if not properly protected, may be attacked or illegally obtained by hackers, resulting in the risk of user privacy leakage or communication information leakage.

c) Spectrum security risks

Unauthorized spectrum use may cause spectrum interference and affect the normal operation of surrounding communication equipment.

d) Network security risks

Smallcell stations are connected to the Internet and may be subject to network attacks, including DDoS attacks, malware attacks, etc., which may lead to communication service interruption or data leakage.

In order to address these security risks, the following measures need to be taken to ensure that the small station operates safely and in compliance with regulations:

a) Device authentication and authorization: Authenticate and authorize Smallcell stations to ensure that only authorized personnel can access and operate the devices. Implement regular password resets and permission upgrades to prevent unauthorized access and operation.

b) Adopt technical means of supervision such as frequency regulation.

c) Regularly conduct compliance reviews of Smallcell sites to ensure that their deployment and use comply with local laws and regulations.

d) Access control and authority management: Implement strict access control and authority management, and classify and restrict the access rights of different personnel.

e) Data transmission security: Protect the security of data transmission between Smallcell devices, use encryption technology to encrypt data, and prevent data leakage and tampering.

V. Summary and Suggestions

Small base stations were born in the 3G era, but are playing their role with the development of 5G networks. Smallell technology solves the problem of deep network coverage in the post-5G era, provides better wireless communication support and user experience for different industries and fields, and becomes an important supplement to cellular network infrastructure. However, with the large-scale deployment and application of Smallcell, the security risks it brings are becoming increasingly prominent. For example, criminals use Smallcell stations to steal user sensitive information, providing a new means for network attacks. In order to deal with the security risks brought by small base stations, the specifications and standards of the small base station industry should be strengthened, including regulations on the location selection, power control, spectrum management, etc. of small base stations, to ensure the compliance and security of small base stations.

References

[1] Gao, Z., Zhang, S. (2022). Encrypted 5G Smallcell Backhaul Traffic Classification Using Deep Learning. In: Su, C., Sakurai, K. (eds) Science of Cyber ​​Security - SciSec 2022 Workshops. SciSec 2022. Communications in Computer and Information Science, vol 1680. Springer, Singapore. https://doi.org/10.1007/978-981-19-7769-5_2.

[2] Guo Honggang. Analysis and research on 5G indoor coverage of radio and television[J]. Wireless Internet Technology, 2022, 19(19):1-4.

[3] Sun Zhaoxi, Liu Chao. Research on indoor coverage of 5G network[J]. Information Recording Materials, 2020, 21(9):2.

[4] Feng Wanrong. Research on Small Cell Self-Healing Technology in Heterogeneous Cellular Networks[D]. Beijing University of Posts and Telecommunications.

[5] Huawei Smallcell White Paper: Five Trends Towards Smallcell 2020