FTTH Solution: A Comprehensive Guide
Explore FTTH Network Design and Key Components Including OLT, ONU, Optical Splitters, and Fiber Distribution Boxes for Reliable Home Connectivity
FTTH Network Architecture
OLT→FDH→FDB→FAT→ONU/ONT
FTTH (Fiber To The Home) is a technology that provides high-quality internet access directly to consumers' homes over an optical fiber infrastructure. This provides users with a dependable and high-speed network service and little to no wait times.
There is no need for an FDB if there is no secondary splitting in the ODN structure or if it's a direct point-to-point connection (P2P).
1. OLT (Optical Line Terminal)
· Located at the central office or in the operator's room.
· Responsible for managing access to users, bandwidth allocation, and user authentication.
· Supports multiple-user access.
· The OLT converts the electrical signals into optical ones and transmits these downstream through the ODN.
2. FDH (Fiber Distribution HUB)
· Fiber Distribution: Distributes the main fiber to various branches.
· Splitter Integration: Includes optical splitters to divide the signal into multiple paths.
· Centralized Management: Provides a centralized point for fiber splicing and maintenance.
3. FDB (Fiber Distribution Box)
· Distributes optical signal from distribution fiber to drop fibre
4. FAT (Fiber Access Terminal)
· Provides fiber-optic access to end users. Typically installed on walls, poles, or hallways
· Protects fiber connections and provides patching interfaces to ONU/ONT
5. ONU/ONT (Optical Network Unit/Optical Network Terminal)
· The ONU/ONT converts optical signals into electrical signals and provides network service.
· ONU (Optical Network Unit), located at the user's end, is typically used in multiuser scenarios (e.g., FTTB). Responsible for converting optical signals to electrical signals and providing Ethernet Interfaces.
· ONT (Optical Network Terminal): Located in the home of the user, providing network services directly to users.
Typically, routers and WiFi are integrated into the device.
Passive Optical Network (PON)
PON is the most commonly used architecture for Fiber to the Home. It includes variations such as GPON, EPON and XG (S)-PON. Each of these variants is tailored to specific performance requirements and applications.
1. GPON
This is a P2MP network, which uses optical splitters to connect fibre to multiple end users.
The split ratio can be up to 1:28; However, the most common is 1:32.
It provides downstream speeds of up to 2.5 Gbps and downstream speeds of up to 1.25 Gbps. GPON has been widely adopted by telecom FTTH systems due to its efficiency.
2. EPON
EPON is similar to GPON, but it uses Ethernet protocols to transmit data.
It generally supports a 1:64 split ratio, with 1:32 being the norm.
It offers symmetric data rates upstream and downstream of 1.25Gbps. EPON's cost-effectiveness makes it a popular choice for municipal and enterprise networks.
3. XG(S)-PON (10G PON) Architecture
The technology is based on GPON, EPON, and other advanced PON technologies. It meets the higher bandwidth requirements.
XG-PON features 10 Gbps downstream speeds and 2.5Gbps for upstream. XGS-PON offers 10 Gbps in both directions. This technology is ideal for high-bandwidth apps, including 4K/8K streaming video, cloud computing, and smart city infrastructure.
Implementation of FTTH Solutions
1. Requirement Analysis & Planning
(1) Needs Analysis & Planning
Define coverage area Analyze the population density, building structure, demand for users, and future trends of growth in the targeted area.
(2) Select Network Architecture
Determine whether you want to use Direct Split Architecture or Cascaded Split Architecture.
(3) Planning Bandwidth and Capacity
Determine OLT specifications, fiber links, and splitter specs to meet your current and future needs.
(4) Budget & Cost Assessment
Create a realistic investment plan by evaluating the costs of equipment, deployment of fibers, and construction.
2. Design of the Optical Distribution Network
(1) Trunk Fiber Cable Design
Define the fiber route, length of cable, and method (aerial duct or direct buried).
(2) Splitter Placement
Determine the split ratio (e.g., 1x32 or 1x64) based on the user density and the position of the splitters.
(3) Fiber Distribution Points Plan
Plan the location of installation for fiber access terminals and fiber distribution terminals.
(4) Select the Fiber Connection Method
Choose between pre-connectorized and fusion splicing options.
3. Construction & Installation
(1) Fiber Cable Installation
Install the trunk fiber cable and the branch cables according to the plan.
(2) Splitter Installation
Install PLC Splitters in the designated places and connect them.
(3) Fiber Splicing & Testing
Use OTDR tests to verify optical signal quality.
(4) User Fiber Deployment
Install FTTH Terminals for ONU/ONT and extend fiber to the end users.
4. Test & Acceptance of System
(1) Optical link testing
To ensure that signals are stable, measure the optical power loss between OLT and ONU/ONT.
(2) Configuration and Optimization of Equipment
Configure OLT/ONU and optimize bandwidth, QoS, and VLAN.
(3) User Interface Testing
Test the normal functionality of broadband, IPTV, and VoIP services.
(4) Troubleshooting and Optimization
Improve performance by resolving detected issues, adjusting the ODN structure, and replacing equipment.
5. Operating & Maintenance
(1) Real-time Monitoring
Monitor OLT/ONU status using a Network Management System to maintain stable operations.
(2) Regular Maintenance
Check fiber connectors and splitters to ensure they are free of dust.
(3) Troubleshooting & User Support
Support your customers 24/7 and respond quickly to any network problems.
(4) Network Optimization
To improve service, expand ODN to include more users and optimise bandwidth allocation.