Optimizing Cell Phone Service for College Football Fans

The equipment room for the distributed antenna system (DAS) at one of the nation’s largest football stadiums.


Picture one of the nation’s largest football stadiums packed with more than 100,000 people, each equipped with his or her own mobile phone. Wireless service providers typically rely on the stadium’s distributed antenna system (DAS) to maximize coverage inside of buildings. Unfortunately, the high-density of a stadium makes it challenging to service the simultaneous mobile connections while maintaining a high-quality signal. After each major event, it’s not uncommon for carriers to receive reports of performance issues that need optimization before the next game.

A senior radio access network (RAN) engineer for one of the largest wireless telecommunications providers in the United States is responsible for investigating signal integrity issues at this stadium. It was becoming prohibitively time-consuming him for to plug-in an RF spectrum analyzer to each radio head to investigate the signals. Instead, he wanted a common public radio interface (CPRI) analyzer that could tap into the baseband unit (BBU) output. This enabled him to easily pull out the IQ data samples and convert them into spectral data in the frequency domain for analysis.

Other significant debugging features included the ability to display multiple signals simultaneously, allowing him to detect system imbalances. Previous experience with competitive analyzers demonstrated very slow boot and setup up times in addition to low sweep rates, resulting in missed data.

When Signal Craft Technologies introduced him to the SignalCraft SIQMA CPRI analyzer, the performance improvement was significant; all the functions ran faster with very little lag time. Plus, SIQMA can capture every CPRI frame for 100 percent interference detection and also provide simultaneous multi-antenna support, offering the highest quality CPRI analysis for the lowest cost.

Because of SIQMA’s easy-to-use interface and fast response times, our customer was able to quickly resolve several DAS issues within the span of a couple of hours.


Figure 2. External interference is clearly shown with the SIQMA interface.

The SIQMA CPRI analyzer provided this RAN engineer with much greater accuracy for troubleshooting and allowed him to record videos of waveforms for further analysis and to show the DAS operator. Also, the client appreciated the portability of SIQMA with its ability to run all day on battery power or plug into AC power.

Read the full case study to learn more about quick and efficient DAS optimization with the SIQMA CPRI Analyzer.