Testing on a Budget

Your team must install new equipment, pro-actively maintain existing infrastructure, learn about new technologies and manage multivendor equipment, all in the wake of corporate belt-tightening. You need to increase your technical staff to meet these demands, but can't afford to pay several technicians the high salaries they command. One answer to your troubles is more sophisticated, cost-effective testing tools that can ease the strain on your workforce and help resolve the conflict of service quality vs. cost.

When it comes to simplifying a technician's job, the most important test-equipment feature is ease of operation. A test set that takes control of the base station and runs a series of automated tests with predetermined pass/fail limits allows less-skilled technicians to test base stations effectively. Automated routines, including functional and parametric tests, are useful for quick installation, commissioning and out-of-service testing during periodic maintenance. You also should be able to use the test set while the base station is live for in-service RF measurements. You need equipment with some level of automated testing so that technicians don't need to understand and become involved in all of the test-process details.

However, true ease of use comes from more than just automated test sequences. Software needs to employ a task-driven approach to lead technicians sequentially through each step, from turning on the instrument to storing final test results. The best possible scenario would be to have a base-station-specific solution. Testing becomes a manageable task with solutions that include all of the necessary connectors, cabling and base-station-specific software. This approach eliminates confusion and turns the instrument into a dedicated test set for a base station.

Automated test sequences need to clearly indicate failures. Then, your test philosophy and the technician's skill level will direct how the problem is handled. The quickest and least demanding method is to replace all suspect modules in the base station and run the automated measurements until the fault is corrected. If an experienced technician is performing the tests, or if module swapping does not fix the problem, you can troubleshoot and pinpoint the problem.

When you replace modules or change the base station in some significant way, technicians will need to run a suite of acceptance or commissioning tests to verify the base station still is operating correctly. Automated testing accomplishes this task with speed and efficiency.

MEASUREMENT REPEATABILITYAlthough easy, efficient operation is a key virtue in a test set, the instrument also must be reliable. According to installation managers, when test equipment is simple to use, often technicians don't need to understand what the test equipment is doing -- as long as the test equipment tells a consistent story.

By bringing high standards of reliability and automation into the field-service environment, technicians can perform the same test sequences in the same way each time, and the test results are compared with the same pass/fail limits. The test set audits the test procedure to ensure accurate and repeatable results.

With a repeatable test instrument, faults are far more likely to be reproduced at the base-station manufacturer's repair facilities, decreasing the risk of costly no-fault returns.

Because of the complexity of CDMA and TDMA measurements, on-screen and printed materials that accompany a test instrument must provide clear instructions for measurement procedures and measurement-result interpretation. Front-panel menus and displays must be laid out and worded to avoid ambiguity, and documentation needs to be similarly constructed.

Next-generation user interfaces are designed to accommodate all user levels with connection diagrams, simple on-screen measurement procedures and easy-to-comprehend measurement reports. Documentation should emphasize usability and focus on application. Good materials will include a quick-start guide, which is a step-by-step guide to getting started with automated testing.

DRILL DOWN CAPABILITYWhen automated testing does not provide the detailed information needed to solve a problem, often you will dispatch an experienced technician to the base-station site. This technician carries a lot of equipment such as a spectrum analyzer, power and voltmeter, frequency counter, antenna tester and signal generator.

To make fieldwork easier, some manufacturers bundle these multiple-instrument capabilities into a 1-box test set. Depending on the specific product, these test sets provide all of the functionality needed to measure transmitter, receiver, combiner and associated antenna performance.

Technicians can perform many of the automated measurements manually to find the source of network faults. Although next-generation user interfaces are designed for fast and simple automated testing, experienced technicians can penetrate that top layer easily to gain access to the rich test capability below. They can, for example, troubleshoot in the frequency spectrum using the test set's built-in spectrum analyzer to locate interference, check feeder-cable performance, make reflection coefficient measurements on antennas or measure insertion loss.

Although no one instrument comprises all possible test functionality, in many instances, these next-generation test sets are all your technicians need to carry into the field for effective cell-site troubleshooting.

ERGONOMIC CONSIDERATIONSWith more base stations to install, optimize and maintain, (including smaller microcells) technicians frequently work on mountain tops, rooftops and in other unsheltered and hard-to-reach areas. Temperature extremes can affect the instrument's performance and render a laptop PC unusable. Wind, rain, snow and dirt can get into exposed hardware and connectors, degrading equipment performance and measurement reliability. If a test set is not designed appropriately, it will fail after repeated use in a hostile field environment. A rugged test set that is truly designed to withstand the rigors of field testing will have:

* A ruggedized case

* Bright electro-luminescent display for easy reading in the sunlight or at night, and in extreme temperatures

* Connectors located for safe and easy stand-up operation

* Capability to be maneuvered in small spaces

* Feet large enough to keep it grounded in mud and puddles

* Ability to sit on a bench or shelf or stand up on end on the ground

* Sealed display and keypad to protect against moisture and dust

* Easy-to-use keypad and knob even for technicians wearing gloves.

Ergonomic features may not affect the technician's skill level directly, but they can improve the overall speed, ease and comfort level of testing performance.

DEPOT-LEVEL TESTINGTools with task-driven approaches also are important features today. With limited resources and the need to reserve experienced personnel for installation and commissioning or complex troubleshooting tasks, many carriers maintain base stations reactively. They respond to alarms by dispatching technicians to the site to swap modules until the problem disappears. Technicians take faulty modules back to a regional center before shipping them to the manufacturer for replacement or repair. Because carriers must pay considerable costs for no-fault returns, they usually install a test set at regional centers to verify a problem exists in each module before shipping it out.

Depot-level testing generally involves running a checklist of tests on each failed module using a proven base station. Your technicians could benefit from software that employs a task-driven approach, which leads them through each testing step sequentially.

EDUCATION & SUPPORTVendors are continually evolving infrastructure solutions. To keep up with the changes, you upgrade base stations periodically. You also must update test equipment to remain compatible. To help protect your investment, some manufacturers offer service contracts for trouble-free upgrades and test-set maintenance.

To round out the skills of base-station technicians, customized education programs can provide hands-on, practical training. Drawing on expertise in measurement, communications and computing, there are programs for CDMA, TDMA and GSM technologies, as well as general base-station test techniques.

Coupled with these support outlets, next-generation test sets can help you maintain high quality of service on a budget regardless of your technicians' skill levels.