Hello, everyone!
Today, I would like to share with you a Final part article on FTTH-PON networks – Standardization and advancement.
The XG-PON, XGS-PON, & NG-PON2 systems all use the same management, TDM multiplexing, and range technology; the only changes are the OLT capacity as well as optical interfaces.
When XG-PON was first introduced in 2010, members were consuming a great deal of data when viewing movies, downloading video clips and tunes, and browsing, but uploading a lot less (except for users of peer-to-peer networks, but on the other hand, ISPs did not like it).
Simultaneously, the XGS-PON project was put on hold because to a lack of enthusiasm from major telecom companies. The focus of ITU-development T's work has turned to expanding OLT capacities.
Nevertheless, increasing the bit rate at a single-carrier wavelength to 40 or 100 Gb/s for transmitting across a conventional single-mode fiber with a range of 20–40 km necessitates multilayered coherent modulation and identification, as well as digital fiber dispersion compensation.
Following 2006, such technology was effectively adopted in core and metropolitan networks, but it is too complex and expensive for access networks.
Rather, a dense wavelength division multiplexing (DWDM) technology was used, with only four or eight wavelengths. TWDM stands for "combination WDM and TDM multiplexing." NG-PON2 has the possibility of disabling certain wavelengths throughout times of low traffic and save energy.
Whilst WDM transmission in a PON with a spectrally nonselective splitter allows for the "stacking" of numerous physical PONs into a single logical PON with a higher capacity, comprehensive use of this attribute necessitates the purchase of costly and not quite technically sophisticated transceivers with configurable transmitters and receivers.
As with WDM-PON, network administrators were cautious of high expenses that were not backed up by profitability in the price-sensitive access market.
During 2015, prominent operators such as Verizon (the very first major client for GPON) had sought the return of XGS-PON, as the market for symmetrical Internet access had grown significantly, and symmetry was necessary to compete with cable Television operators whose DOCSIS 3.0 networks couldn't handle it.
The ability to have 2 upstream bit rates in 10G EPON reduced the symmetry challenge, but the relatively expensive pricing of 10 Gb/s transceivers compared to 2.5 Gb/s devices for GPON hardware hindered installations, and GPON has dominated since 2010.
Until 2016, China's business use of 10G EPON was confined to connecting switches in FTTB networks.
In 2015, IEEE started working on the NG-EPON standard, which includes TWDM multiplexing and a Nx25 Gb/s data rate. To attain a 20-kilometer range, additional complicated solutions must be used instead of the standard two-level (on/off and NRZ) modulation.
In 2017, Huawei Technologies and BT Openreach tested a prototype 4x25 Gb/s symmetric PON system created by Huawei Technologies.
You are welcome to leave a message and exchange in the comment area. Thank you!
