Design Considerations for Spectrum Monitoring Systems
Due to spectrum congestion and sophistication of wireless communication technologies, it is an ever-increasing challenge to monitor spectrum, particularly considering the rapid growth of wireless, satellite, and point-to-point communication devices. Regulators are asked to hunt for and resolve RF interference in this crowded and complex spectrum.
There are two likely scenarios. There is a-priori information on the emitters to be tracked or tested, e.g., approximate frequency and amplitude. Here, traditional spectrum analysis techniques and equipment will work extremely well. Alternately, there is no prior knowledge.
Without control of the RF/microwave airspace and with little information about the target signals, the RF spectrum-monitoring task is a discovery process. Signals of interest reveal themselves to spectrum monitoring because many wireless signals vary in power, duration, and bandwidth. Some of the complex interactions between systems may actually be harmonics of known emitters, translated into frequencies where they become unwanted interferers. There can be thousands, even tens of thousands of irrelevant signals that need to be ignored when capturing data on emissions of interest.
Key considerations in the design of spectrum monitoring systems include types of equipment, speed and sophistication of data capture and processing, degree of integration with software tools for analysis and comparison with other license and type approval data. Other considerations include proximity to active airspace, staff skills, and mobile versus fixed locations.
State-of-the-art spectrum monitoring equipment is highly integrated. Integration typically involves the use of graphical user interface (GUI) based spectrum management tools and systems which are specifically designed to operate multiple electronic components simultaneously and remotely over data protocols such as TCP/IP. This allows for an integrated network system for management of the radio spectrum using remote devices. These devices can be located at existing government sites and facilities on the outskirts of population centres. Remote devices permit access to monitoring equipment from anywhere through compatible computer, a modem and a telephone line or network connection (LAN or WAN). Remote devices can be controlled in several ways:
Locally from the server;
Remotely across a LAN;
Modem over a WAN.
There are equipment and organizational and functional aspects to architecting spectrum monitoring systems.
The key technical equipment components are described in Section 6.3.1 Monitoring Equipment. Additional equipment components in a monitoring system include: buildings, power supplies, mobile vehicles and man portable components.
Organizational components include centralized, regional and remote locations for siting of monitoring equipment in stations and operational staffing or use of unmanned remote capabilities, where applicable.
In addition to technical equipment, functional components of spectrum monitoring systems include: central monitoring control; operational consoles for operation of equipment and analysis of data; and data networking and management systems for data communications and repository.