Wireless Coexistence Impacts and Test Methods

NIST CTL’s Shared Spectrum Metrology Group is developing new interference metrics to gauge the how well wireless devices in increasingly crowded RF environments coexist while operating in shared frequency bands. The National Broadband Interoperability Testbed (NBIT), which our group operates, plays a central role in these efforts, as does our work to develop distributed spectrum-monitoring systems.

We need new interference metrics because technological advances in computing, signal processing, and computational speed are enabling systems to work well in cluttered RF environments that would have degraded the performance of past systems.

The work aims to identify insightful, easy-to-interpret key performance indicators (KPI) that are based on real-world scenarios, yielding meaningful, measurable, comparable, repeatable and quantitative results. Among the coexistence metrics under consideration:
   • Transmission power
   • Channel usage statistics
   • Signal to noise ratio (SNR)
   • Signal to noise + interference ratio (SNIR)
   • Error Vector Magnitude (EVM)
   • Bit Error Rate (BER)
   • Packet error rate (PER)
   • Time of application response
   • Quality of application response

Using KPIs based on these and other measures, we aim to provide deeper insights into coexistence and its impact on wireless system performance and user experience. These insights can, in turn, help industry develop equipment even more capable of operating in crowded wireless conditions.