Hi everyone!
Today I will continue to write migration from GPON to XG(S)-PON. Now, I will explain the hybrid solution for migration from GPON to XG(S)-PON. Let's get started.
Telecommunication operators require a reliable and easy migration from GPON to XG(S)-PON. ODN is the largest part of the access network. Most of the investment is invested in that part of the access network. GPON and XG(S)-PON standards use different wavelengths (figure 1.), so it is possible that both standards coexist in the same ODN. It is very important. In this way, telecommunication operators can offer GPON and XG(S)-PON in the same ODN.
Figure 1. Different wavelengths for GPON and XG(S)-PON
Most modern OLTs (such as the Huawei MA5800) support XG(S)-PON. Thanks to this fact, it is possible to migrate from the current to the next PON standard in two ways:
using an XG(S)-PON boards (hybrid solution) and
using only Combo or Flex PON boards.
Hybrid solution
This solution is to use XG(S)-PON service boards within the same OLT with the existing GPON service boards or a special OLT in which there will be only XG(S)-PON service boards. Simultaneous and parallel operation of these two standards is enabled by the use of WDM multiplexer/demultiplexer. In this way, both standards are enabled at ODN. Users can choose GPON or XG(S)-PON and the ONU/ONT device depends on it.
Figure 2. The hybrid solution
The advantage of this technology is the retention of existing GPON service boards. All previous investments remain. But this solution has disadvantages, too. Introducing a new element - WDM MUX/DEMUX requires changes and additional space in the headend or central office. In addition, this component introduces additional IL (Insertion Loss), which is about 1 to 1.5 dB. Using this solution for migration requires an upgrade software of OLT and NMS. In some cases, it may require the replacement of control boards.
Figure 3. Process evolution from GPON to XG(S)-PON
At one point in the future, all users will use the new standard. Then, the entire system switches to XG(S)-PON, which will mean the GPON service boards and WDM MUX/DEM will uninstall.
This is the end of this article. I hope you have learned something new.
I will continue to write about this topic in the next article >> Evolution from GPON to XG(S)-PON (4).
Thank you!
