LoRa Duty Cycle Ceilings That Decide Payload Frequency
LoRa duty cycle ceilings restrict packet frequency by limiting hourly transmission airtime, forcing trade-offs between spreading factor, payload size, and battery life.
Channel Dwell Time
Meaning
Regulatory limits restrict the maximum duration a radio transmitter can continuously occupy a single frequency channel. This channel dwell time ensures that the spectrum remains available for other users by forcing devices to stop transmitting or switch to a different frequency after a set period. Compliance with these timing constraints is a requirement for certification in many regions, including North America and Europe.
Regulatory Compliance
Government agencies set these limits to manage the density of wireless traffic in unlicensed bands. A device that exceeds the allowed channel dwell time can be barred from sale or operation within that jurisdiction.
Frequency Hopping
Systems that use spread spectrum technology often jump between many different channels to distribute their energy across the band. The time spent on each hop must stay below the legal limit to maintain a legal and fair use of the airwaves.
Throughput Constraint
Short limits on occupancy can reduce the amount of data a device can send in a single burst. Engineers must optimize the packet size and the data rate to fit the required information into the window allowed by the channel dwell time. If a message is too long, the system must split it into multiple fragments, which increases the overhead and complexity of the communication protocol.