1.    Application reports timeout


Description of fault: when hand-held WLAN scanners are used, the connection of the application used is terminated with a "timeout" at irregular intervals. In order to resume regular operation, the device must be restarted manually.

 

Cause and solution proposal: troubleshooting revealed that the WLAN terminals were not configured optimally and were equipped with an unsuitable firmware version. During ensuing client certification, the client's optimum WLAN settings were determined for the customer's infrastructure. In cooperation with the terminal manufacturer a stable firmware image was developed, which helped to eliminate the problems associated with using that particular client.   


2.     Automated guided vehicles come to a stop


Description of fault: the automated guided vehicles stop at a specific position along their route. The vehicles only continue once they have been moved some meters along the route by means of manual control.

Cause and solution proposal:
during the as-is analysis of the WLAN coverage in the relevant areas of the AGV route, it was found that - contrary to what the customer assumed - the problems were not caused by an insufficient WLAN signal level. Spectrum analysis identified a further radio system in the 2.4 GHz frequency band that transmits a strong narrow-band permanent signal on the central frequency of the local WLAN channel. The interference caused in the radio channel prevents communication between the AGV and their control center so that the vehicles are forced to stop. A frequency management concept coordinated the frequencies used by the two radio systems and any further ones. This solution has eliminated the interference and prevents future disruptions.



3.    Low data throughput and slow page loading in the intranet


Description of fault: in office environments, the WLAN connection only achieves very low data throughput with laptops and intranet pages can be very slow to load.

Cause and solution proposal: an on-site interference study including WLAN protocol analysis identified several reasons for the low data throughput and the slow loading of intranet pages in the office environment. We found several access points with outdated hardware that were thus no longer able to cater for the large number of users and the resulting data volume. The analysis also found a strikingly high channel load caused by a less than optimum configuration of the WLAN controllers, which was adapted to customer requirements on the spot. A follow-up study was commissioned to look into several access point models sourced from varying manufacturers, which the customer planned to use. These tests were completed in the customer's real-life environment and served as the basis for a decision on the replacement of all outdated access points.



4.    Noise and connection termination during VoWLAN telephone calls


Description of fault: users experienced problems during telephone calls over VoWLAN telephones in various parts of the building. They complained about noise or even connections being terminated during the telephone call.


Cause and solution proposal: troubleshooting found that some areas were no longer sufficiently covered by the WLAN due to structural alterations within the building. The WLAN design was used to plan coverage in these areas for the use of VoWLAN telephones and to optimize the existing WLAN infrastructure in the remaining areas of the building. This optimization not only resulted in the problems being eliminated but also in significantly reducing the number of access points required.