The optical fiber repeater is mainly composed of optica […]
The optical fiber repeater is mainly composed of optical near-end machine, optical fiber, and optical remote machine (covering unit). Both the optical near-end machine and the optical remote machine include a radio frequency unit (RF unit) and an optical unit. After the wireless signal is coupled from the base station, it enters the optical near-end machine, through electrical-to-optical conversion, the electrical signal is converted into an optical signal, from the optical near-end machine to the optical fiber, and transmitted to the optical remote machine through the optical fiber. The signal is converted into an electrical signal and enters the RF unit for amplification. After the signal is amplified, it is sent to the transmitting antenna to cover the target area. The working principle of the uplink is the same. The signal transmitted by the mobile phone passes through the receiving antenna to the optical remote machine, then to the near-end machine, and returns to the base station.
Near-end machine: Master Block, master control unit
Remote unit: Slave Block, which is a controlled unit/slave unit/covering unit
1. There are actually many ways to obtain the input signal of the near-end machine, such as donor antenna, coupling base station, RRU, etc.;
2. The near-end machine is generally installed in the base station machine room, and the remote machine is installed at the edge of the coverage area or at an appropriate location inside (see indoor or outdoor coverage). The remote machine usually needs to install an ODB (optical fiber distribution box). ).
The directional antenna of the near-end device of the fiber optic repeater receives the downlink signal from the base station and sends it to the near-end host, amplifies it and sends it to the optical transceiver for electrical/optical conversion, transmits the optical signal with wavelength of 1.55&1.31μm, and then sends it to the optical multiplexer , The optical signal of the original transmission link (wavelength: 1.31μm) is combined and transmitted to the far end via the optical cable; the remote optical wavelength splitter separates the optical signal of the 1.31μm and 1.55μm wavelengths, and allows the 1.55μm wavelength of the optical signal The input optical transceiver performs optical/electrical conversion and restores it to a downlink signal, which is amplified by the internal power amplifier of the remote host, and transmitted by the omnidirectional antenna to the mobile station. The uplink signal of the mobile station is sent to the base station in the reverse direction, thus completing the signal connection between the base station and the mobile station and establishing a call.
A near-end machine can be connected to multiple (usually 1-4) remote machines. The near-end machine is usually small and is usually installed in a cabinet. The remote machine is larger and is generally mounted on the wall.
The biggest difference between an optical fiber repeater and a wireless repeater is the transmission method of the base station signal. The optical fiber repeater transmits through optical fiber, while the wireless repeater transmits through space. Therefore, the optical fiber repeater has the following characteristics:
①The output signal frequency is the same as the input signal frequency, transparent channel.
②The shrouded area antenna can be omnidirectional or directional according to the terrain.
③There is no isolation problem of wireless repeater transmission and reception, and the location is convenient.
④The distance between the optical fiber relay end and the near-end machine should not exceed 20 kilometers.
Ningbo Guangdao Communication Technology Co., Ltd.(https://www.nb-fibercome.com)