FTTA Networks

The Full Test Solutions for FIber-to-the-antenna (FTTA) Deployment

In the stone age of cellular phones, back when voice communication was the only offering, network design focused on coverage, not capacity. Today’s phones have morphed into portable, application-oriented, internet-enabled computers, greatly increasing the strain on network capacity. Unfortunately, adding new macro sites, microcells and picocells simply won’t cut it. A better way to augment the macro layer is by adding low-power nodes like femtocells, remote radio heads/units (RRHs/RRUs) and distributed antenna systems (DAS).

By bringing high data rate to the radio/antenna, fiber-optic links deliver the promises made by mobile broadband. Increasing broadband capacity means growing the wireless network, which decreases the cell radius. Therefore, feeding bandwidth to the entire wireless infrastructure means increasing fiber connectivity and penetration. Essentially, more wireless means better and deeper wireline.

Two standards are used to carry traffic over fiber from the base station’s radio equipment controller (REC) to the radio equipment: common public radio interference (CPRI) and open base station architecture initiative (OBSAI). CPRI is the predominant standard.

Today’s Mobile Networks Reality

The purpose of any fiber-optic network is to perform high-speed, error-free data transmission. Adequate testing during each phase of the network deployment guarantees that products meet specifications, in addition to minimizing costly and time-consuming troubleshooting efforts, including locating dirty/damaged connectors, questionable splices and other faulty components before they disrupt service.

Typical FTTA Scenario

One of the most important factors in ensuring proper transmission is controlling power loss in the network against the link loss-budget specifications from the network design recommendation. This is done by establishing a total end-to-end loss budget with sufficient margin while reducing back reflection to a minimum. This is particularly true for analog RF video signals from extremely narrowband lasers, because strong back reflections degrade the quality of the signal transmission.

Testing Procedure

Once the design of the network has been completed, the lifecycle of a network generally consists of three main phases: construction, activation and maintenance. The following sections highlight some the key testing elements that should be considered during the Construction and Service Validation Phase.

1.Construction Phase

• Step 1 ; Connector Cleanliness

Fiber connector inspection and maintenance (at each connection point)

EXFO’s FIP-400B Fully Automated and Intelligent fiber inspection solutions are designed to speed up and simplify this critical step to any fiber testing and help you deploy faster, more reliable fiber networks, providing accurate and consistent test results, and preventing the reporting of false-positive results.

KEY FEATURES

• 100% automated, one-step inspection process
• On-board connector endface analysis
• (IEC, IPC or custom standards) including MPO/MTP analysis.
• Pass/fail LED indicator for immediate diagnosis of connector health
• Optimal digital image quality with three levels of magnification
  

• Step 2 ; Fiber Characterization

Installation of a fiber loop (Rx to Tx) for loopback testing (at the RRH), and then Characterize end-to-end fiber link, validate loss budget and identify faults (from base station)

The most recent test tool for this application is the intelligent optical link mapper (iOLM). This tool uses the same method as the OTDR, but performs the test procedure automatically. It does this by using different pulse widths to fully characterize the various sections of an FTTH network—each section being characterized with the optimal pulse. Then, the iOLM consolidates all this information into a single comprehensive Link View; the operator does not have to manually compare results at different pulses like a traditional OTDR. The iOLM provides the link’s loss and ORL, in addition to identifying all network elements such as splices, splitters and connectors. It also provides the loss and reflectance values of the identified elements. And when a specific element or the link itself gets a “fail” verdict, it offers a diagnosis to help the operator solve the problem. The whole routine takes 30 to 60 seconds, depending on network complexity.

iOLM Test Result

(For more information about iOLM, Click here)

2. Service Activation Phase

• Remote Radio Head (RRH) and Baseband Unit (BBU) Validation

1. RRH validation using baseband-unit (BBU) emulation with a CPRI protocol analyzer at the specified rate (from base station)
2. BBU validation using RRH emulation with a CPRI protocol analyzer at the specified rate (from base station)
3. Verification that small form-factor pluggable (SFP) transceivers are installed and connected correctly
4. Test at the bottom of the base station, or kilometers away

(For more information about CPRI Testing, Click here)

One Field-Optimized Test Solution

Leveraging the powerful, intelligent FTB-1 Prohandheld test platform, the FTB-700G V2 Series is an automated Ethernet, multiservice and optical testing solution for fixed and mobile networks that integrates all the required testing functionalities needed to effectively activate, validate and troubleshoot wired, wireline, centralized RAN (C-RAN), fiber-to-the-x (FTTx), fronthaul, backhaul, small cell, distributed antenna system (DAS) and data-center networks into a single module.

the FTB-700G V2 Series streamlines processes and empowers field technicians to efficiently test and validate optical networks, SONET/SDH, OTN, Fibre Channel, CPRI and Ethernet circuits.

(For more information about FTB-700Gv2, Click here)