Meaning
Signal detection parameters in wireless receivers define the power level above which an unscheduled radio frequency transmission is classified as an active channel. Setting the energy detection threshold determines the boundary between thermal noise and a valid signal from an alien transceiver. Devices evaluate the received power within a specific channel bandwidth before attempting to transmit.
When the measured power remains below this value, the transceiver categorises the spectrum as clear.
Receiver Sensitivity
The selection of this value directly influences the trade-off between false alarms and missed detections. A low energy detection threshold causes the node to defer transmission even when the interfering signal is too weak to cause a collision, which reduces the channel utilization. Conversely, a high threshold can lead to collisions if the device transmits while a hidden node is actively communicating.
The optimum point balances these risks based on the density of the network. RF engineers must adjust this parameter during system integration to match the specific antenna gain and cable losses of the final product assembly.
Calibration Accuracy
Analog-to-digital converter resolution and low-noise amplifier gain stability determine the accuracy with which a transceiver can enforce this limit. Thermal drift in the RF front end can shift the perceived noise floor, which requires periodic calibration to maintain consistency. When calibrations are skipped, the device can suffer from erratic medium access behavior.
Regulatory Compliance
Global spectrum sharing rules, such as those defined by the Federal Communications Commission, mandate specific threshold levels for unlicensed devices. Testing laboratories verify compliance by injecting calibrated RF bursts into the antenna port of the device. The equipment must reliably detect these bursts and withhold transmission within the required time window.
