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Analysis of 5G fronthaul Semi-active WDM Scheme

Date: 2021-09-24 02:31:26 From: C-light Onclick:

The 5G prequel has experienced an upgrade from "none" to "existence" and then to "excellent". 5G fronthaul failures are nearly 10 times worse than 4G, and potential optical path failure points have increased significantly. The impact on 5G availability cannot be ignored, and fronthaul is a key bottleneck for 5G network availability. Therefore, the construction of 5G fronthaul needs to integrate the economy, operability and availability of the entire life cycle. At present, CWDM/LWDM/MWDM/DWDM and other 5G fronthaul WDM bearer solutions coexist and develop, and the semi-active WDM solution supporting the OAM mechanism has become a hot spot for fronthaul deployment.


What is the fronthaul semi-active WDM solution?


The semi-active WDM scheme refers to the use of passive WDM equipment on the RRU/AAU side and the use of active equipment on the BBU/DU side. A coupler is connected in series between the passive wavelength division multiplexer and the optical fiber line on the AAU side, and signals of different wavelengths are transmitted in one optical fiber after passing through the passive wavelength division multiplexer; the multiplexer and demultiplexer on the DU side Optical switch components are connected in series between the optical fiber lines to forward the color light signal forwarded, and perform operation and maintenance on the color light module of AAU. This solution takes into account the saving of optical fiber resources and proper operation and maintenance.



On the BBU/DU side, the two ports of the optical switch are respectively connected to the optical fiber of the main route and the backup route. When the optical fiber link of the main route fails, the optical switch automatically switches to the optical fiber link of the backup route. The coupler on the AAU side is equivalent to a 1:2 optical splitter, which can receive the signals of the main and backup optical fiber links at the same time, and couple the optical signals from the AAU into the main and backup optical fibers at the same time.


A 1:2 non-uniform optical splitter OPS is also connected in series between the optical switch on the BBU/DU side and the optical fiber line to realize the monitoring of the optical fiber link. OPS splits a small amount of light from the optical link to the optical monitoring device PD, as shown in the figure below. The PD can read the transmission network management information modulated in the optical signal by the optical module in the optical link, and transmit the monitoring information to the network management.



Advantages of semi-active WDM solution


Semi-active equipment takes into account the simple and low-cost characteristics of the remote AAU side passive. Through the intervention of active equipment, it effectively solves the shortcomings of passive WDM that cannot be managed and maintained. It can monitor the status of the forward-wavelength division optical network in real time and provide the optical layer. The 1:1 protection ensures the transmission reliability of the 5G fronthaul service link. The network management of semi-active fronthaul equipment usually supports SNMP, CLI, WEB, Telnet network management protocols, and also has remote monitoring and management (OSC) functions, which improves network OAM management performance and brings great convenience to equipment maintenance and management.


The semi-active fronthaul solution has three major characteristics to meet the needs of high-quality 5G network construction.

* 12-wave large capacity, double the passive solution

* Can be operated and maintained, with protection support, and the network availability rate has increased to 5 9

* High-performance 10km transmission distance to meet any deployment scenarios


C-light Passive/Semi-active products for WDM application


* Newly launched SOA amplifier products that complemented medium and long distance transmission for 40G/100G/400G products Expand requirements.

* There is a relatively mature EDFA FTTX scheme.

* Very strong in CWDM/ DWDM MUX/DEMUX universal solution availability (price/delivery capability).

* Very flexible and customizable capability (for insert loss/connector/size/package screen printing, etc.)

* Various successful customized solutions (e.g., single-wave unidirectional/multi-wave bi-directional /6nm spacer narrow pass/industrial MUX)


C-Light DWDM optical module


* The use of the most advanced made in China EML signal processing chip, relative to the traditional overseas Semtech, Tl chip cost is reduced by 30% and the sensitivity is greater than 26dB. The supply guarantee ability is completely independent and free!

* The most mature EML/DML photonic chip made in China is used to produce customizable BOX/TOSA/BOSA encapsulated laser, relative to imported brands Mitsubishi, Broadcom, Sumitomo brand. The cost is reduced 50%, and the supply security ability is completely independent and free.

* We are ahead of most companies in the fiber optic industry to complete 155M/622M/1.25G/2.5G/3G/10G/16G of domestic design and switch to mass production.

* We have the ability to manufacture DWDM industrial grade, and BIDl products.

* We have 25GHZ/ 50GHZ/ 100GHZ/ 200GHZ DWDM product design and supply ability.

* The standing stock of DWDM series products is 100 sets.


C-Light CWDM optical module


* With the most advanced domestic refrigeration chip, the CWDM wavelength drift is less than 3nm under the shell temperature of -40~85℃, achieving the real industrial wavelength and error code.

* It has a communication scheme supporting CDR 10G CWDM optical module and mass production.

* It has a variety of single-fiber CWDM single-wave and multi-wave solutions that most companies in the industry cannot provide optical module products.

* MPO 40G CWDM PSM production capability.

* Capable of supplying a variety of high sensitivity CWDM optical modules.

* The standing stock of CWDM series products is 300 sets.


C-Light optoelectronic product research and development


* C-Light's R & D team has the mature design capability of brand high-speed communication solutions, such as MAXIM, SEMTECH, MACOM, ZTE, UX, HISILICON, and MARVELL, and supports customization according to customer standards.

* The C-Light engineering team has a self-made high-speed (100G/25G/10G) production test system, client evaluation system and professional ability of brand universality testing.

* lnstruments for analysis and testing of error code, spectrum and data signals. We also offer a client brand switches with speeds up to 400G, which are used as test environments for practical applications, and C-Light's R&D department testing specialists provide project environment for the clients to testify research and develop products and problem checking.