New progress in millimeter wave 5G

The propaganda about 5G is booming and in full swing, making people believe that the real millimeter wave 5G will appear in front of you like a moving high-speed train. But in fact, most 5G services may take years to become viable. The 15th release of 3GPP brings a new process for 5G that exceeds many companies' expectations (except for the telecom companies that lobby for them), namely, additional sub-6 GHz frequency bands and non-independent millimeter wave protocols.

This allows wireless service providers to formally promote 5G services, although the performance standards of these services are far less than the revolutionary advantages of 5G that people often say. Although impressive, the 15th edition or 5G NR (5G New Radio) seems more like a continuous upgrade of 4G LTE, except that millimeter wave signals can also be used with the frequency spectrum below 6 GHz to create higher bandwidth, thereby Improve data rate and connection performance [1, 2]. In many large cities, in addition to large stadiums, arenas, and transportation hubs that are considered viable areas for millimeter wave 5G, there are still many limitations in other areas.

There are several factors, many of which are beyond the scope of the radio access network (RAN) and extend to the backhaul and core network infrastructure. In many places and instances, neither the core network nor the architecture used for design can provide critical millimeter wave 5G functions. These features include throughput of up to 10Gbps, latency of less than 1ms, the ability to provide services for various types of communication (including large-scale machine-to-machine communication), higher reliability, and the so-called "last mile Internet connection" "Service" for fixed wireless access for homes and small offices.

If the core network is not the limiting factor, then the backhaul network or RAN may become the limiting factor. In order to achieve Gbps speed and low latency, as well as the reliability that must be available in any environment, some people believe that the core network and some backhaul networks need to be "fiberized" or connected based on high-speed fiber. Optical fiber installation is not only expensive and relatively complicated to operate, but it is also not feasible to install optical fibers in many areas. Under these circumstances, some people believe that several macro-cell heterogeneous network architectures equipped with millimeter-wave backhaul may be able to provide services to countless millimeter-wave Small Cells required to effectively cover metropolitan areas [3]. Others believe that the core network, backhaul network, and RAN should be designed as a whole system, rather than separate but interconnectable parts. Since the future 5G service may dominate the traffic flow and the number of users in the future subway area, this is most likely a feasible direction. However, many cities have invested heavily in core network and backhaul network resources, and it may take some time to upgrade their existing infrastructure.