5G Technology Development and Future Applications
An Overview of 5G Network Architecture
5G Overall Network Architecture, Software-Based and Service-Oriented 5G Core Network Architecture, and Non-Standalone and Standalone Network
In this article, I will introduce the 5G network architecture. This article consists of three parts. The first is the overall architecture of the 5G network, showing you the tremendous change from the end-to-end of 5G technology. The second part introduces the architecture of the 5G core network. In the last part, I will briefly explain the two modes of 5G that are relatively unique. One is the non-standalone network (NSA) and the other is the standalone network (SA).
Let’s first look at the overall architecture of 5G networks. It can be said that the end-to-end 5G network has a tremendous change from devices, wireless networks, transmission networks, core networks, and business.
5G Overall Network Architecture
5G Devices have undergone major changes.
The first is different form factors appear. Due to the emergence of various usage scenarios, the form of the terminal has also changed greatly. It is not only a smartphone, but also VR/AR glasses in the future, and the equipment of the car, including the television set at home, and the refrigerator, including the drone in use. Yeah, GSA had identified fifteen announced form factors (phones, head-mounted display, hotspots, indoor CPE, outdoor CPE, laptops, modules, snap-on dongles/adapters, enterprise routers, IoT routers, drones, robots, TVs, head-mounted displays, a switch, USB terminals, and a vending machine).
The biggest change of the 5G devices is that it has a higher transmission power, which is 3dB higher than the transmission power of current 4G devices, to reach 26 dBm.
Another big change is that more antennas have appeared in the device. The basic test we are doing now using 2T4R (two antennas for transmission and two for reception). 4R has basically become a standard option. 2T is now in the process of being promoted.
The air interface defined by 3GPP for 5G is known as New Radio (NR). The first biggest change on the NR is that it has greater bandwidth. It is required that the low-frequency band below 6GHz can reach a bandwidth of 100 MHz, and then the high-frequency band above 6GHz can reach a bandwidth of 400 MHz, which can be said to have a very large improvement over LTE.
Massive MIMO (multiple-input and multiple-output) uses large numbers of antennas. The antenna we have can reach 64 channels and 192 arrays.
The design of the entire 5G wireless network also changed greatly. The first one, there is a new concept, beamforming. It is used to direct radio waves to a specific target to improve signal quality and data transfer speed. In 5G, we can have more fine-grained management and scheduling of the beamforming for more precise quality control of the customers
There is also a new design of a new reference signal, the DMRS (Demodulation Reference Signal), which is a new encoding method.
Another new technical feature is the flexible parameter configurations, including a shorter frame configuration and minislot parameters for shorter frame scheduling.
A new network architecture appears on the entire network architecture. This is a centralized unit (CU) and distributed unit (DU) separated network architecture. Unlike 4G, 5G base stations are split to CU and DU. This is a major change in network architecture.
There is a new way of transmitting system messages in our high-level design, not only a broadcast mode but also an on-demand transmission mode. New states of the terminals may appear. In LTE, it is mainly connected state and idle state, but a new state called deactivated state may appear in 5G. This is a major change in wireless networks.
One relatively large change in the transmission network is its greater exchange capacity: From 640G to 12.8T.
It also provides higher performance, the transmission delay between its nodes requires a very large improvement, that is, it reaches 10 nanoseconds, the time error can reach nanoseconds.
A new SDN technology is introduced to the transmission network to achieve global intelligent scheduling, intelligent operation and maintenance.
On the core network, we said that its changes can be simplified to what we simply call the Four Modernizations.
The first is IT, the second is the Internet, the third is extremely simplified, and the fourth is service-based. The most typical change in the network architecture of the core network is to propose a service-based network architecture, such as SBA, to separate the control plane from the user plane. There are also technologies that support network slicing and edge computing. In the next section, I will give you a detailed introduction.
The new business is related to the typical usage scenario I have written in the previous article. Because 5G will support three types of usage scenarios, namely eMBB, URLLC, mMTC, so our business will also have such diversified services based on these three types of usage scenarios. For example, 5G can provide communication between vehicles and communication between vehicles and infrastructures to realize self-driving cars.
Remote surgery and remote healthcare are possible with the use of the high-speed 5G network. With the connections to equipment and devices at home, smart homes can be achieved.
Software-Based and Service-Oriented 5G Core Network Architecture
Let me show you the relatively tremendous changes in the 5G core network architecture. As you may know about LTE, the core network of LTE is basically a rigid network. It can be said that from the base station, the serving gateway, MME, and PDN Gateway are all such fixed connections, and their functions are also fixed functional modules, fixed signal interactions. When we read the specification of the protocol, we may know that the protocol defines the transmission of a specific message in an interface between different nodes, and defines the format of that message.
However, when 5G is adopted, there will be an extraordinary change in the core network architecture. It can also be said that a change from CT to IT integration is that there will be a message bus type architecture. All the previous functions are fixed on each device, but we may now have different function modules, and each function has been implemented into this so-called soft network, at which we can deploy custom-defined network functions and network connections. Each of the functions can be connected through a bus, and when this function is needed, the interface on this bus will be called. The device name of the entire network is also updated because its functions are updated. So the three main pieces of equipment of the core network are briefly introduced: AMF (Access and Mobility Management Function), SMF (Session Management Function), and UPF (User Plane Function). In the LTE network, all session management functions were distributed on various devices, including MME, Serving Gateway, and PDN Gateway. However, in a 5G network, we will concentrate these functions on the SMF, so we completely separated this user plane and control plane, and carried out a clearer division of this function. Therefore, this bus-based service-based network architecture is a relatively large feature of the 5G core network architecture.
Non-Standalone and Standalone Mode
Let me introduce you to the more unique networking modes that have emerged in 5G. We know that the previous generations of technology are basically that each generation of technology is end-to-end, from the terminal, base station, to the core network, everything is new. However, due to the different requirements of different operators for network deployment time in 5G, including consideration of investment cost, 5G has a relatively unique networking model called Non-Standalone (NSA) mode. 5G will have two modes: Standalone (SA) mode and Non-Standalone (NSA) mode.
For NSA, there are new 5G NR, but the device will be connected to the 4G base station and the 4G core network for the signaling plane. The 5G base station only performs data offload, whether it is data offload from our 4G base station or data offload from the 4G core network EPC. This is the most typical Non-Standalone network, that is, the 5G network cannot run independently. It must rely on the existence of the 4G network. The device is connected to the 4G EPC through the LTE base station for signaling. In fact, there are many options of Non-Standalone mode in the standard, but the most typical choice is to choose option three, the mentioned one.
SA refers to new 5G equipment and devices from the top to the bottom, from the terminal to the base station to the core network. 5G networks can operate independently. The operation between 4G and 5G is performed through the interoperation between the 5G core network and the 4G EPC, or through the operation between the upgraded LTE base station and the new 5G core network. These are mainly the two unique networking modes.
This series introduces 5G network knowledge, including 5G usage scenarios, network architecture, air interface key technologies, transmission network evolution, candidate spectrum, network slicing, etc. to help you understand 5G technology and business application scenarios.