The full name of 5G NR is 5G New Radio. We can get a glimpse of its meaning from the name. The so-called "New Radio" contains two words: "new" and "radio". This leads to two questions: What is a radio? Where shows it is new?
The mobile communication system is mainly composed of two subsystems: terminal, base station, and core network. Among them, the terminal and the base station constitute the base station subsystem, and many complex network elements in the core network constitute the network subsystem.
The terminal is generally our most commonly used mobile phone. The base station is the guy with high towers that can transmit signals. The core network is located at the back, essentially a router, which connects the base stations so that they can communicate with each other.
Among them, the interface between the mobile phone and the base station is called the "radio" because the base station and the mobile phone propagate in the air through electromagnetic waves. It can be seen that the radio is dedicated to the inside of the base station subsystem and has no direct contact with the core network.
In the 5G era, the independence of the two subsystems, the base station and the core network, has increased. Therefore, 5G is very flexible. It can be networked independently or non-independently with 4G. In the independent networking, the 5G base station is connected to the 5G core network; in the non-independent networking, the 5G base station and the 4G base station can be connected to the 4G core network or the 5G core network.
When 4G base stations and 5G base stations are connected to the same core network, they form a 5G non-independent networking system. In this way, regardless of whether the connected core network is 4G EPC or 5G 5GC, the same mobile phone has two air interface connections, and the link to the 4G base station is the "old radio", and the connection to the 5G base station is the so-called The "new radio" is now. The 5G new radio is designed based on the 4G air interface technology, and also uses the OFDM modulation method. Some unreasonable aspects of 4G are corrected in the frame structure, and the support for large connections and low latency is added, so it is more flexible and the spectrum efficiency is also higher.
There are three main ways for operators to deploy 5G NR:
① Non-independent deployment (NSA): LTE + 5G NR millimeter wave
This type of deployment is represented by Verizon and AT&T in the United States, deploying 5G NR millimeter waves on existing LTE networks to supplement coverage hotspots or deploy 5G fixed wireless.
② Non-independent deployment (NSA): LTE + less than 6GHz NR frequency band
This deployment method can quickly achieve better 5G NR coverage, but there are technical complications such as the interface between 4G LTE and 5G NR and carrier aggregation.
③ Independent deployment
It is to directly deploy a complete 5G network, which simplifies the process of non-independent deployment to the 5G core network. The complexity is low, but it requires complete and mature 5G coverage and ecology.