The NIST CTL’s spectrum sensing and monitoring research and development efforts focus in three areas: sensor technology, monitoring infrastructure, and analysis of spectrum occupancy to aid in real-time wireless-access coordination.
In sensor technology, the NIST CTL is:
- Developing wideband sensor technology and signal processing algorithms to increase the accuracy and effective bandwidth of sensors (the early focus being on the 3.5 GHz band)
- Developing sensing algorithms capable of more than simple energy detection – such as cyclostationary and matched-filter sensing – that exploit known characteristics of the signal to improve sensing performance in low signal-to-noise ratio (SNR) environments
- Assessing the various windowing functions commonly used for spectral analysis, as well as the kernel functions for quadratic time-frequency representations, and their impact on detection performance
- Implementing the above techniques and algorithms on a range of readily-available software-defined radio (SDR) platforms, for feasibility assessment and dissemination as open-source software modules
- Validating the above techniques using instrumentation-grade high-dynamic-range and/or high-bandwidth analog-to-digital converters (ADCs).
In monitoring infrastructure, we are:
- Creating a scalable architecture, interface specifications, and representative implementation for gathering, storing, and presenting spectrum-occupancy measurements. Parcel to this effort includes:
- Developing a database for long-term storage of spectrum-occupancy measurements
- Developing a graphical user interface (GUI) and application program interface (API) for access to stored measurements
- Building front-end servers for receiving and analyzing real-time, streamed measurements
- Calibrating low-cost spectrum sensors
- Performing uncertainty analysis of spectrum occupancy measurements
- Developing SDR sensor software for calibration, database population, and real-time measurement streaming
- Investigating the use of wide-bandwidth (~1 GHz or more) ADCs to coordinate the array of sensors
- Identifying additional properties – such as protocol identification, waveform traces, and sufficient time/frequency resolution – to ensure compatibility with coexistence and interference metrics.
In work related to the analysis of spectrum occupancy for real-time coordination, the NIST CTL is:
- Developing statistical models of spectrum occupancy derived from long-term measurements and comparing them with existing occupancy models in the literature
- Creating efficient algorithms for real-time calculation and near-term prediction of spectrum occupancy to support dynamic spectrum coordination.