WAVIoT trials showed a 32 km signal transmission range in harsh urban area
WAVIoT has completed the massive NB-Fi based smart metering IoT solution. The test field was in one of the megalopolis in harsh urban built-up surroundings. Here are some details about our tests. The exact location for NB-Fi Base station installation is one of the key success factors for ensuring stable long-range wireless communication.
We have planned to install the base station on the top of 230 m skyscrapers, but the circumstances allowed us to set the antenna only on the top of a 25-story building with a total height of 60 meters.
Based on the theoretical calculations, the line of horizontal sight from the 60 m building is about 30 kilometers. That is the earth-point signal distance.
One of the key NB-Fi protocol technical benefits is the signal communication reliable opportunity at -3 dBm below the noise floor level.
As the modem has already got out of sight and the signal went down below the noise floor, we expected that further moves will not give any results. But as we can see, the base station has been receiving the data packets with some minor errors.
The final packet has been received at 32 kilometers distance which was out of the view. We assume some reflections from the hi-rise buildings. By that moment, signal strength went down the noise floor at -3 dBm.
One sector antenna has been installed on top of the building with a recommended 7' vertical tilt. The surrounding environment included a lot of tall and other concrete buildings a which were much higher than the base station installation spot.
The measured noise level in the installation place was significantly high -133 dBm in the 50 Hz band.
After the base station installation, WAVIoT team has been making the signal measurements every 3-5 kilometers. Reference 17 dBm signal has been sent from the standard testing modem which is equipped with a button.
The maximum signal transmission range observed by the team with no omission errors reached 30 kilometers. At this range, the signal strength comes down to the noise floor of -133 dBm.