With the issuance of 5G licenses in China, 5G optical networks are in full swing. In addition to the core network expansion and transmission of 5G optical networks, the fiber-optic transmission equipment is also widely used in the construction of 5G base stations. Today,engineer of Sharetop will share the most common solutions for the 5G base station prequel.
Before introducing the base station pre-transmission solution, let's understand some basic terms of base station transmission.
Radio frequency transceiver module, the RF unit (commonly called RRU).
AAU (Active Antenna Unit) is a mobile network initiated by the macro base station, and then developed to the distributed base station to save the loss and greatly improve the network coverage. The AAU (Active Antenna Unit) series base station is a new form of base station based on AAS technology and integrated RF and antenna design.
RRU and antenna integrated in one AAU
Highly integrated AAU replaces traditionally large numbers of loose parts
The baseband processing module, that is, Baseband Processing (abbreviated as BBU). For the baseband processing of the BBU, we can split it into: 1. Non-real-time slow processing module (such as handover, RRC connection management), Non Realtime. With this module, we have the possibility to focus on clouding, called CU. 2. Real-time fast processing modules (such as codec, fast scheduling), Realtime, this part, we are difficult to cloud, still placed close to the site, called DU.
For CU, DU, how do we physically deploy, there are several options: 1, CU and DU are placed in the BBU box, placed on the site, this is the most familiar 3G/4G base station form, which is RRU+ BBU (including CU and DU) This traditional way, we call DRAN, distributed, emphasizes the separation of baseband and RF modules, 2, CU and DU are placed in the BBU box, the BBU box finds a machine room, centralized stacking, reaching It saves space and equipment room facilities, and at the same time allows BBU resources to be stacked and shared. The site deploys RRUs, and the BBUs are centrally stacked in a machine room close to the site (usually a few kilometers to a dozen kilometers away). In this way, we call CRAN, centralized, which emphasizes the centralized deployment of BBUs.
A fiber optic connection is required between the RRU (radio remote module) and the BBU (baseband processing unit). A BBU can support multiple RRUs. What we call the base station preamble is the optical transmission between the BBU and the RRU.
Several 5G base station pre-transmission solutions introduced by the industry are as follows:
5G Base Station Forwarding Solution Overview