Application of WDM in 5G Fronthaul
411 2023-02-03
The 5G era has arrived. If the traditional optical fiber direct connection solution is adopted, the 5G fronthaul network will require a large amount of optical fibers, which not only requires high deployment costs, but also complicates post-operation and maintenance. Therefore, in the 5G era, it is necessary to explore innovative fronthaul bearer solutions. The fronthaul solutions in the 5G era mainly include: optical fiber direct connection, passive WDM, semi-active WDM and active WDM. Today we will introduce the application of passive WDM in 5G fronthaul.
The passive wavelength division multiplexer (WDM) is designed to solve the fiber resources for long-distance transmission between the distributed unit (DU) and the active antenna unit (AAU) in the centralized radio access network (C-RAN) 5G fronthaul architecture Insufficient problem, in addition, passive WDM can also save fiber resources. In passive WDM, colored optical modules are directly deployed on AAUs and DUs, and multiple AAUs can share one optical fiber for transmission through passive WDM without power supply at the remote end. Passive WDM is the most suitable solution for 5G fronthaul. According to different wavelengths, 5G passive wavelength division multiplexers can be divided into CWDM (coarse wavelength division multiplexing), DWDM (dense wavelength division multiplexing), MWDM (medium wave Division Multiplexing) and LWDN (Wavelength Division Multiplexing).
Application of WDM Network Topology in 5G Transmission
The passive WDM network topology in 5G transmission consists of fronthaul and backhaul. The 5G fronthaul interconnects the AAU/RRH (active antenna unit processing unit/radio remote head unit) to the CU/BBU (central unit/baseband unit), and the 5G backhaul interconnects the CU/BBU to the core network.
Advantage
The solution of carrying passive WDM in 5G fronthaul has the following advantages: high bandwidth, high reliability, cost-effective CPRI rate, low latency, low insertion loss, low cost, 4/6/8/12/18/24 /48 optional channels, significantly saving fiber, plug and play, easy to install and deploy, easy to maintain
Application Scenario
Passive WDM is suitable for end-to-end C-RAN network scenarios, areas where optical fibers are scarce, and areas that lack pipeline resources. Potential application scenarios for passive WDM include: 5G fronthaul, oil and gas, industrial, electric power, mining, cable TV, FTTx, passive optical network, etc. HTF can provide different types of passive WDM, and can customize base on customers’ requirements.
Different Passive WDM Solutions
Passive WDM solutions include CWDM, DWDM, MWDM and LWDM.
(1) CWDM
CWDM uses wavelength multiplexing technology, which has the advantages of high bandwidth, high channel isolation, low temperature sensitivity, and low cost. It enables operators to transmit 18 bands simultaneously in a pair of optical fibers.
(2) DWDM
DWDM is a cost-effective solution with point absorption modulated lasers (EM). It features high reliability and stability, high channel isolation, high bandwidth, low insertion loss and less complexity.
(3) MWDM
MWDM focuses on the first 6 wavelengths of CWDM, compresses the 20nm wavelength interval of CWDM to 7nm, and uses thermal electron cooler (TEC) temperature control technology to expand 1 wave to 2 waves, which can further save fiber resources while achieving capacity Increase. .
(4) LWDM
LWDM is based on Ethernet communication wavelength division multiplexing (LAN WDM). Its channel spacing is 200~800GHz, which is between DWDM (100GHz, 50GHz) and CWDM (about 3THz). LWDM provides high reliability and stability, high channel isolation and low insertion loss. In addition, LWDM can support 12-wave 25G to increase capacity and save fiber.
In conclusion
Passive WDM can help solve 5G front-end transmission problems by saving fiber resources and reducing costs. Passive WDM bearer rates include 10G, 25G, 40G, and 100G. In addition, passive WDM has the advantages of high bandwidth, high channel isolation, low delay, low insertion loss, simple maintenance, and easy deployment.