Optical Path Device Planning in FTTR Scenarios

Optical Path Device Planning in FTTR Scenarios

Background Introduction

        The traditional FTTH (Fiber To The Home) networking solution uses a single optical modem and router, with network cables only reaching the distribution box or living room. Wi-Fi coverage is limited, and after the signal passes through walls, both signal strength and speed deteriorate significantly, making it impossible to achieve high-speed Wi-Fi coverage throughout the home.

        The FTTR (Fiber To The Room) whole-home smart gigabit fiber solution adopts a mode where a 10-gigabit main optical modem connects to N slave optical modems. Fiber connections are used throughout, whether in hallways or rooms. It offers strong transmission capability, higher transmission rates, and a longer lifespan than network cables. It supports 10-gigabit uplink connections and achieves true whole-home Wi-Fi 6. This allows every family member to enjoy the best gigabit broadband experience anywhere in the home, meeting high-quality service requirements such as home VR, 8K ultra-HD TV, high-definition online education, e-sports gaming, and future whole-home smart applications. So, how are optical path devices planned in FTTR scenarios? 

        Depending on the fiber connection method between the FTTR main and slave optical modems, there are two FTTR technical networking solutions: Point-to-Multipoint (P2MP) and Point-to-Point (P2P). The P2MP solution is the primary one, based on PON technology. The principle of PON technology is shown in Figure 1:

        Although FTTR and FTTH use the same core PON technology, due to differences in application scenarios—such as the short distance between the FTTR main gateway and its slave gateways, and typically no more than 16 slave gateways—the following optical path aspects need to be considered in actual deployment and planning:

Optical Module Selection

        The main optical modem is equivalent to a mini OLT. Due to the short transmission distance inside the home and the number of slave gateways generally not exceeding 16, a lower-power GPON Class B+ optical module can be selected to save costs.

      Hilink's SFP GPON OLT Class B+ 20km optical transceiver module is a GPON OLT in SFP package, compliant with the ITU-T G.984.2 standard. It supports 2.488Gbps continuous mode transmission at 1490nm DML and 1.244Gbps burst mode reception at 1310nm APD/TIA. The module offers efficient functionality and feature integration, accessible via a two-wire serial interface. Optical signals are multiplexed onto single-mode fiber through a standard SC connector. In addition to these, we also have GPON OLT C+, C++, C+++, 9DB, 10DB.

      In Combo FTTR scenarios, the upstream interface of the main optical modem adopts a Combo BOSA device that integrates both GPON and 10G PON physical channels, supporting on-demand remote switching of operating modes, enabling PON link load sharing and differentiated service assurance at the central office side.

Splitter Selection

        Home layouts are complex. It is recommended to adopt single-stage or multi-stage splitting solutions based on the situations in the table below.

Note: 1:5 and 1:9 unequal splitters have higher costs, and some manufacturers have alternative solutions. For large flat-floor and villa scenarios, unequal splitters are recommended to optimize optical power distribution.

Splitter Attenuation Reference Values (for Optical Power Budget)

        Currently, the device-level maturity of FTTR technical solutions is gradually improving. To ensure network performance meets service requirements, more attention needs to be paid to engineering aspects such as cabling specifications and optical path budget planning in actual deployment.