The difference between RRU and BBU, what is the difference between BBU and RRU, and what do they do

1. The scope is different:

The BBU+RRU multi-aisle solution takes advantage of the fact that there are floors between floors, walls in rooms, and space division between indoor and indoor users. For large stadiums of more than 100,000 square meters, the stands can be divided into several districts, each of which is provided with several channels, and each channel corresponds to a panel-like antenna.

2. The distribution is different:

Generally, the indoor distribution system adopts the electrical distribution mode of cables, while the BBU+RRU scheme adopts the distribution mode of optical fiber transmission. The baseband BBU is centrally placed in the computer room, the RRU can be installed on the floor, and the BBU and RRU are transmitted by optical fiber, and the RRU is connected to the antenna through coaxial cable and power divider (coupler), that is, the backbone is optical fiber, and the branch is coaxial cable.

3. Different directions:

For the downlink direction: the optical fiber is directly connected from the BBU to the RRU, and the baseband digital signal is transmitted between the BBU and the RRU, so that the base station can control the signal of a user to be transmitted from the designated RRU channel, which can greatly reduce the interference to users on other channels in the community.

For the uplink direction: the user's mobile phone signal is received by the nearest channel, and then transmitted from this channel to the base station through the optical fiber, which can also greatly reduce the interference between users on different channels. The BBU+RRU solution is very flexible in capacity configuration, and can support the expansion of each channel from 1 6 carriers to 3 carriers by configuring BBU according to capacity requirements without changing the RRU and indoor distribution system.

1. The concept is different

Because it is not a homogeneous concept in the first place, but it should be said that the specific relationship between the two is like. I hope you find this article helpful. Radio Remote Unit The technical characteristics of the wireless remote unit are that the base station is divided into two parts: the near-end machine, that is, the wireless baseband control (Radio Server) and the remote machine, that is, the radio frequency remote unit (RRU), which is connected by optical fiber, and the interface is based on the open CPRI interface, which can be stably connected with the equipment of mainstream manufacturers.

2. Different locations:

RS can be installed in a suitable computer room location, RRU is installed on the antenna end, in this way, a part of the previous base station module is separated, by separating RS from RRU, the tedious maintenance work can be simplified to the RS side, and an RS can be connected to several RRUs, which not only saves space, but also reduces the installation cost and improves the networking efficiency.

3. The interface is different

At the same time, the interface between the two uses optical fiber, which has low loss Building Base Band Unite -- Indoor Baseband Processing Unit The 3G network uses a large number of distributed base station architectures, and the RRU (Radio Remote Module) and BBU (Baseband Processing Unit) need to be connected with optical fiber. One BBU can support multiple RRUs. The BBU+RRU multi-channel scheme can be used to solve the indoor coverage of large venues.

Usually large buildings have floors between floors, rooms with walls, and space division between indoor and indoor users, and the BBU+RRU multi-aisle solution takes advantage of this feature. For large stadiums of more than 100,000 square meters, the stands can be divided into several districts, each of which is set up with several passages, and each passage corresponds to a panel.

1) Use differently.

1. The power divider is a device that realizes signal distribution.

2. The combiner is to combine the signals of the same frequency band and different frequency bands.

3. There is no problem in using the combiner as a power divider.

4. When using the power divider as a combiner, it should be noted that the input signal is required to be of equal amplitude.

5. However, it should be noted that both should pay attention to the power capacity and frequency band range when using.

2) The principle is different.

In my opinion, a duplexer and a combiner are different, and a duplexer is generally used at the output and input end of the device to isolate signals from different frequency bands. For example, the uplink and downlink signals of mobile communications.

Combiners are generally used in hardware circuits for power synthesis. For example, to get a 40 dBm signal, two power amplifiers with an output power of 20 dBm can be combined.

The internal structural principle of their should also be different, the inside of the duplexer should be a filter cavity (large duplexer), and the inside of the combiner should be a coupling circuit.

3) Different names.

The term "combiner" has been used in two places, to distinguish one is the heterogeneous combiner, also called the antenna sharer, simply put, several filters share a port, saving the number of antennas.

PTN is connected to the network, BBU is connected to PTN, RU is connected to BBU, RRU is connected to the antenna, and the antenna sends out a signal, and your mobile phone has a signal.

Take Huawei as an example, 3161 micro single channel, 3152, 3172 are dual channels (also divided into AC DC, generally DC).

If you want to see whether it is 3G or 4G, you can directly look at the main control board, umptb3, umptb4, which are 4G upgrades and new main control boards. UMPTb7 is the main control board for 3G.

RRU is a remote radio unit, and BBU is a building baseband unit.

BBU (Bui LDING Base Band Unite) is an indoor baseband processing unit. The baseband processing functions (encoding, multiplexing, modulation, and spread spectrum, etc.) of the UU interface, the IUB interface functions of the RNC, signaling processing, local and remote operation and maintenance functions, and the working status monitoring and alarm information reporting functions of the NodeB system are completed.

RRU (Radio Remote Module). The RF Remote Unit (RRU) is divided into 4 large modules: IF module, transceiver module, amplifier and filter module.

The digital IF module is used for modulation and demodulation, digital up-and-down conversion, AD conversion, etc. for optical transmission; The transceiver module completes the conversion of the intermediate frequency signal to the radio frequency signal; Then through the power amplifier and filter module, the RF signal is transmitted through the antenna port.

3G networks use a large number of distributed base station architectures, and the RRU (Remote Radio Module) and the BBU (Baseband Processing Unit) need to be connected with optical fiber. One BBU can support multiple RRUs. The BBU+RRU multi-channel scheme can be used to solve the indoor coverage of large venues.

Optical fiber is used to transmit between the BBU and RRU, and the RRU is connected to the antenna via a coaxial cable and a power divider (coupler).

That is, the backbone adopts optical fiber, and the branch adopts coaxial cable. In the TBU distribution system of BBU+RRU, the cell setting is on the control board of the BBU, and several RRUs may be connected behind a BBU, but not each RRU is a cell.