Rohde & Schwarz has extended the functionalities of its R&S AVQA advanced voice quality assurance system from IP to radio frequency (RF). This takes advantage of the ED-137 protocol with information such as the frequency ID or radio signal strength indicator (RSSI). With this information, R&S AVQA provides great new insights into the RF channel.
High-quality voice communications are paramount in air traffic control (ATC) and need to be maintained. In mid-2020, Rohde & Schwarz released R&S AVQA, a groundbreaking monitoring solution for voice communications in air traffic management. Later that year, the company introduced RSSI monitoring as a unique enhancement to R&S AVQA.
The RSSI monitor provides short-term and long-term statistics on the signal and noise distribution received by radios. This gives radio engineers valuable insights into the RF spectrum behavior. If an air traffic controller reports poor transmission quality, the source, such as a weak signal or poor IP transmission, is easy to discover.
Another new function is the frequency monitor, which automatically monitors the utilization of a radio channel. It also provides user behavior analytics of air traffic controllers and pilots and allows disturbances in the RF spectrum to be quickly and easily recognized. Users are automatically alarmed of irregularities such as long pressed PTT or long SQL as well as technical issues such as SQL/PTT drops.
R&S AVQA uses a patented loopback monitor for continuous, non-intrusive monitoring of the RF transmission and reception channel. In a typical installation, the RX and TX sites are geographically distributed to reduce interference. R&S AVQA takes advantage of the systemwide monitoring and correlates both signals. The system also monitors signal delay and the RSSI level, which must be within the predefined range. If irregularities occur, the system alerts the user.
"Air traffic is recovering and communications systems need to be ready to handle the future increase in air traffic," explains Jindrich Slavik, ATC portfolio manager, Rohde & Schwarz. "R&S AVQA provides non-intrusive IP and RF assurance for air traffic communications, helping to quickly identify hidden impairments in the infrastructure and to ensure compliance with legal requirements."