What is 5G's forward, intermediate and backward transmission

⦁ Logical Architecture Diagram of 5G Mobile Communications
      Before figuring out the 5G pre-transmission, mid-transmission and back-transmission, let's understand the logical architecture diagram of 5G mobile communication, the 5G network architecture consists of three parts: access network, bearer network and core network:

Figure 1 Logical architecture diagram of 5G mobile communication

      Take two cell phones for example, the communication data has gone through several links: cell phone A → access network (base station) → bearer network → core network (telecom room - bearer network - backbone network) → bearer network → access network (base station) → cell phone B.
      Access network is generally a wireless access network, which is what we usually call RAN (Radio Access Network), which realizes the function of connecting all cell phone terminals to the network. We often talk about the base station, which belongs to the radio access network, 5G pre-transmission, intermediate transmission and back transmission are relative to the base station.
⦁ Composition of the base station
      In 4G communication, a base station usually includes BBU (mainly responsible for signal modulation), RRU (mainly responsible for RF processing), feeder (connecting RRU and antenna) and antenna. Each 4G base station has a BBU and is directly connected to the core network through the BBU.

Figure 2 Comparison of the composition of 4G and 5G base stations

      The base station of 5G network is reconfigured into the following three functional entities: CU centralized unit, DU distribution unit and AAU active antenna unit.
      CU: The non-real-time part of the original BBU is split out and redefined as CU, which is responsible for processing non-real-time protocols and services.
      AAU: Part of the physical layer processing function of BBU and the original RRU and passive antenna are combined into AAU.
      DU: The remaining functions of BBU are redefined as DU, which is responsible for processing physical layer protocols and real-time services.
      So the 4G network has only two parts, pre-transmission and backhaul, while in the 5G network it evolves into three parts, the part of the AAU connecting to the DU is called pre-transmission, the part of the DU connecting to the CU is called mid-transmission, and the communication bearer between the CU and the core network is called backhaul. It should be noted that, according to the standards proposed by 5G, CU, DU and AAU can be separated or combined, so a base station may not necessarily have the three forms of pre-transmission, mid-transmission and back-transmission at the same time.
      Moduletek Limited can provide optical module solutions for 5G pre-transmission, mid-transmission and return transmission.
      If you have any questions about the above content, you can contact us by Email : web@moduletek.com