A Quick Start Guide to Fiber-to-theAntenna (FTTA) Installation and Maintenance Testing Vol.
A Quick Start Guide to Fiber-to-the-Antenna (FTTA) Installation and Maintenance Testing Vol. 2 — Tier 2 Certification Notice Every effort was made to ensure that the information in this document was accurate at the time of printing. However, information is subject to change without notice, and VIAVI reserves the right to provide an addendum to this document with information not available at the time that this document was created. Copyright © Copyright 2017 VIAVI Solutions. All rights reserved.
Table of Contents FTTA .......................................................................................................................................................................................................................4 Macrocell and Fiber Components .................................................................................................................................................................... 5 Inspect Before You Connect ...............................................
FTTA Staggering increases in bandwidth demand are forcing network operators to new models of mobile infrastructure like FTTA to improve the user experience and reduce costs. Optimized cabling and component performance between the radio remote unit (RRU) and the base band unit (BBU) is key to delivering optimized system performance between the backhaul network and the end user. Network professionals must ensure network uptime and reliability while maximizing the customer experience.
Macrocell and Fiber Components This guide will focus on macrocell fiber installation and maintenance tests. This type of network architecture generally involves RRU and BBU functions that are physically separated. The radio equipment is relocated next to their respective antennas in the RRU enclosures. Fiber is deployed using a remote fiber feeder cable (RFF) that interconnects the BBU located at ground level to a breakout box at the top. The fiber is then patched using a jumper into the RRU.
Connectors Fiber connectors enable fiber-to-fiber mating by aligning the two optical fibers. Fiber connectors come in various types and have different characteristics for use in different applications.
Simplex Fiber Core Cladding Ferrule Fiber endface view Body: Houses the ferrule that secures the fiber in place; utilizes a latch and key mechanism that aligns the fiber and prevents the rotation of ferrules of two mated connectors. Ferrule: Thin cylinder where the fiber is mounted and acts as the fiber alignment mechanism; the end of the fiber is located at the end of the ferrule which is referred to as the endface. The overall diameter of the ferrule depends on the relevant connector type.
Inspect Before You Connect Contamination is the #1 source of troubleshooting in optical networks! A single particle mated into the core of a fiber can cause significant back reflection (return loss), insertion loss, and equipment damage. Visual inspection is the only way to determine if fiber connectors are truly clean before mating them.
Inspect INSPECT Inspect Bulkhead 1. Select the appropriate bulkhead inspection tip that corresponds to the connector type and install on a probe. 2. Insert the probe into the bulkhead to inspect. 3. Determine whether the bulkhead is clean or dirty. yy If clean, do not touch it and CONNECT yy If dirty, CLEAN Inspect Patch Cord 1. Select the appropriate patch cord inspection tip that corresponds to the connector type and install on probe. 2. Attach the patch cord to the probe. 3.
IS IT CLEAN Inspection Criteria Dirt is everywhere, and a typical dust particle (2 – 15 μm in diameter) can significantly affect signal performance and cause permanent damage to the fiber endface. Most field test failures can be attributed to dirty connectors, and most connectors are not inspected until the problem is detected, after permanent damage has already occurred. Zones and Acceptance Criteria Zones are a series of concentric circles that identify areas of interest on the connector endface.
IS IT CLEAN Acceptance Criteria The tables below list the acceptance criteria standardized by the International Electrotechnical Commission (IEC) for single-mode and multimode connectors as documented in IEC 61300-3-35 Ed. 1.0. Single-Mode PC Connectors, RL ≥26 dB (Ref: Table 5) Zone Name Diameter Defects Scratches A. Core 0 – 25 μm 2 ≤3 μm none >3 μm none 2 ≤3 μm none >3 μm none B. Cladding 25 – 120 μm no limit <2 μm 5 from 2 – 5 μm none >5 μm no limit ≤3 μm none >3 μm C.
CLEAN Clean Clean Bulkhead with the IBC™ Guide cap cover Guide Cap Nozzle 1. Select the appropriate cleaning tool for the connector type. Nozzle extender lock Guide cap cover 2. Pull off the guide cap cover. Repeat steps 3, 4, and 5 if necessary. Dry Clean 3. A ttach the cleaning tool to the connector and push the cleaner into the patch cord two times (two clicks). Impact Determine whether clean or dirty. 4. I f clean, do not touch it and CONNECT 5.
CONNECT Connect There are three basic principles that are critical to achieving an efficient fiber optic connection: yy Perfect core alignment yy Physical contact yy Pristine connector interface Today’s connector design and production techniques have eliminated most of the challenges to achieving core alignment and physical contact. What remains challenging is maintaining a pristine end face. As a result, contamination is the #1 reason for troubleshooting optical networks.
TEST Test Fiber Continuity A visual fault locator (VFL) emits visible light to let technicians easily see light escaping from bends or breaks in the fiber. This is ideal for continuity checking and also to provide a means to identify the correct RFF fiber is routed to the correct RRU port.
TEST Optical Time Domain Reflectometer (OTDR) Testing An OTDR is a fiber optic tester for characterizing fiber and optical networks. It detects, locates, and measures events at any location on the fiber link. The ability of an OTDR to characterize a fiber is based on detecting small signals that are returned back to it in response to the injection of a large signal, a process similar to radar technology.
1 Front-end reflective event Connection between the OTDR and the patchcord or launch cable. 2 Connector Loss TEST (L) (L) Ghost An unexpected event resulting from a strong reflection causing “echoes” on the trace. When it appears, it is often seen after the fiber end.
TEST OTDR Testing During the Construction Phase Testing Tx and Rx Fibers Using a Loopback (recommended) During construction, a patchcord loop (20 m) is placed on each duplex pair after tower/rooftop installation: a patch cord is looped at the top for a test of the duplex pair. A patch cord allows the two duplex pairs to be measured for loss and reflectance.
TEST OTDR Testing During the Construction Phase Testing Tx or Rx Fibers (no loopback) During construction, a receive cable (10 – 20 m recommended) is placed at the top of a tower/rooftop, connected to the RRU jumper, to allow the measurement of an entire link and the far-end connector loss and reflectance. A non-reflective terminator or an APC connector is recommended to minimize the reflectance on the far connector.
TEST OTDR Testing During the Maintenance Phase During the maintenance phase, a launch cable is placed between the OTDR and the base station connector (10 – 20 m recommended) allows the loss and reflectance of the base station connector to be measured. Because of a limited access to the top of a tower/rooftop on the far end, the fiber is plugged into the RRU equipment. Before performing the OTDR measurement, make sure that the fiber being tested has no signal and that the equipment is shut down.
OTDR Results Interpretation on a T-BERD/MTS-2000 To speed up the interpretation of measurement results, a Link Mapper View provides results in a schematic map for immediate diagnosis of problems.
OTDR Results Interpretation on a T-BERD/MTS-2000 Detailed Result Page 1. Auto detection and identification of cell tower elements 2. Event position, loss and reflectance per tested wavelength 3.
TIER 2 Certification Report As with Tier 1, a Tier 2 certification report provides documentation to prove fiber performance and quality of work. The goal is to certify work with onboard PDF reports generated directly from the OTDR. A typical Tier 2 certification should include details related to all OTDR events detected during the acquisition.
VIAVI Essential Fiber Test Tools for FTTA Tier 2 Certification VIAVI acceptance test tools: y Ensure reliable, robust operation of the mobile infrastructure y Future-proof the network to survive environmental effect and aging equipment and components y Optimize system component and equipment performance y Drive best practices and field operational efficiencies y Prevent unnecessary operational costs such as tower climbs Visual Fault Locator The FFL-050 has a compact, ergonomic design for ultimate portabili
VIAVI Essential Fiber Test Tools for FTTA Tier 2 Certification 4100 Series OTDR Modules for T-BERD/MTS-2000 and 4000 Platforms OTDR modules enable field technicians to rapidly, reliably, and costeffectively install, turn-up, and troubleshoot any optical network architecture—enterprise, FTTx, access point-to-point, point-to-multipoint passive optical networks (PONs), and metro.
Contact Us +1 844 GO VIAVI (+1 844 468 4284) To reach the VIAVI office nearest you, visit viavisolutions.com/contacts. © 2017 VIAVI Solutions, Inc. Product specifications and descriptions in this document are subject to change without notice. fttavol2-qsg-fit-nse-ae 30175765 901 1017 viavisolutions.
