Maintaining wireless service

Communications News, Sept, 1998 by Joseph B. Caldarone

A remote monitoring and testing system, combined with predictive facilities, helps Bell Atlantic Mobile keep its network online.

Building a wireless telecommunications network involves unique challenges, such as cell site location and spectrum allocation; but it also involves all of the problems a land-line carrier faces, including network testing and performance monitoring. When Bell Atlantic Mobile began building its wireless telephone network, testing initially was implemented in the time-honored fashion: field engineers were situated across the network and were equipped with portable test sets.

Bell Atlantic Mobile's Network-Operations Control Center (NOCC) is located in Bedminster, N.J., and is responsible for the operation of the entire Bell Atlantic Mobile network. The NOCC operates 24 hours a day, 7 days a week. Network failures are identified by the NOCC, where technicians analyze each problem and, until recently, worked with regional switch engineers and local land-line telephone companies to locate the problem and correct it. This process can take several hours, especially if the trouble call comes in at night or on a weekend, when on-call field personnel might have to drive an hour or more to reach an office, or when a local company might have only a skeleton staff on duty. Furthermore, relying on somebody else to perform circuit testing was undesirable.

The common perception of the wireless industry is that customers are individuals who sign up for wireless telephone service one by one and use their wireless phones strictly for voice. While many of Bell Atlantic Mobile's customers fit this profile, there are also many corporate and government customers who use their wireless phones for both voice and data. Many public safety vehicles, for example, now have onboard computers that use the network to send and receive data.

Regardless of the profiles, all customers--large and small-expect the network to be fully operational and have little tolerance for service interruptions. Clearly, a faster means of locating network problems was needed in Bedminster.

NETWORK TESTING

One part of Bell Atlantic Mobile's solution was installing the REACT 2001 remote test system from Hekimian Laboratories, Inc. in the NOCC. The system communicates with remote test equipment to monitor, set up loopbacks, and perform the other operations necessary to test a circuit.

Entering a circuit identification number causes the REACT system to download circuit information from the network database. This information is used to display a circuit diagram on the screen. The technician then uses a mouse to choose the point on the diagram at which to test and also to choose the type of testing to be done. Results are displayed on the same screen.

Implementation of the new system has been relatively trouble free. NOCC technicians have welcomed it because it makes their job simpler. Because REACT works from the network database, implementing testing has required that information in the database be corrected (or completed in some cases), but this updating would have been needed eventually anyway.

With the system operational in one region of the network and coming online in a second religion, the time savings have been dramatic. After identifying a problem, technicians in the NOCC are able to fully test a circuit in minutes, right through to the cell site, before alerting a field engineer or contacting a local telephone company. Some 600 T1 circuits currently can be tested through the system, with more being equipped all the time.

PERFORMANCE MONITORING

A second part of the solution to the network monitoring and testing challenge is due to be implemented in the coming months. Hekimian' s PM Integrator performance monitoring support system will be installed to allow proactive monitoring of circuit quality. During the night, the PM Integrator system will upload daily performance monitoring data from network elements equipped to collect it, then analyze the data to calculate a figure called the quality index for each circuit. Circuits for which the quality index is below a certain threshold will be listed on a report each morning. Technicians can examine the circuits on the report to determine why performance is degrading.

Using the performance monitoring system will let Bell Atlantic Mobile identify problem T1 circuits before they actually cause network problems. The system will be accessible from remote terminals to provide performance-monitoring analysis capabilities at regional offices as well as at Bedminster.

In addition to these systems, other systems are being added to the NOCC to perform other functions to enhance alarm monitoring. We want the NOCC to be the central point of support for all of our network elements. The ultimate goal is to allow a single technician at a single terminal to perform all network troubleshooting functions (including both switching and facilities equipment), and to bring a second-tier support function to the NOCC.