Sleep Current Arithmetic behind a Five Year Battery Claim
Five-year battery claims require balancing microampere sleep floors, primary cell passivation derating, and protocol airtimes across 43,800 hours.
Link Budget Airtime
Meaning
Transmission durations representing the time a wireless packet occupies the physical medium represent an essential temporal resource in network capacity planning. The link budget airtime determines how long a radio transmitter must remain active to deliver a payload successfully over a given distance. Lower signal levels require more redundant modulation, which increases this duration.
Minimising this parameter is necessary to prevent network congestion.
Modulation Dependency
Path loss directly influences the selection of the data rate and the resulting transmission duration. When the signal is weak, the system falls back to slower, more redundant modulation schemes, which increases the link budget airtime for each packet. Conversely, a strong signal allows high data rates that complete the transmission rapidly.
Designers use link budget calculations to predict these transitions.
Network Throughput
Every millisecond a transmitter is active reduces the available capacity for other devices on the same frequency. If a single node consumes excessive link budget airtime due to a poor connection, the overall network performance drops. Dynamic rate adaptation algorithms attempt to balance this by steering nodes to closer gateways.
This prevents a single distant sensor from blocking the channel for closer, faster devices. Systems that use duty-cycled networks must enforce strict limits on packet sizes to keep the channel open for emergency alerts.
Power Consumption
Long transmission times translate to higher energy usage for battery-powered devices. The link budget airtime dictates the duration of the high-current state of the radio. Minimizing this duration is a priority for battery optimization.