pamoja-lora

LoRa link math for pamoja: exact time-on-air and duty-cycle off-time, so a long-range node stays within regulations and budgets its power, no_std and allocation-free.

The same capability in every language

LoRa link math for the pamoja SDK.

LoRa is the SDK's answer to reach: kilometres of range on license-free bands at tiny power. That reach comes with a hard constraint, though. A LoRa transmission occupies the channel for a duration fixed by the radio settings, and the regional regulations a deployment lives under cap how much of the time a node may transmit, typically around one percent. A node that ignores this is both illegal and, since transmitting is the most expensive thing it does, wasteful of its battery.

This crate provides the arithmetic that keeps a long-range node honest, with no radio and no floating point:

• LinkSettings - the spreading factor, bandwidth, coding rate, and frame options of a link, with airtime_us for a payload's exact time on air and min_off_time_us for the silence a duty-cycle limit then forces.

The time-on-air calculation is the published LoRa formula, evaluated with exact integer arithmetic, so the same numbers a deployment planner uses are available on the node itself. It pairs naturally with the metered-link batch encoding in pamoja-codec - pack a batch, then ask what it costs to send - and with the duty-cycling in pamoja-power.

This is the link-budget half of LoRa support; driving the radio arrives with the hardware-I/O layer.

Examples

use pamoja_lora::LinkSettings;

let link = LinkSettings::new(12, 125_000); // SF12, 125 kHz: maximum range
let airtime = link.airtime_us(20); // time on air of a 20-byte payload

// At a 1% duty cycle, the node must then stay quiet for ninety-nine times as long.
assert_eq!(link.min_off_time_us(20, 10), airtime * 99);

License

MIT - part of the pamoja workspace: one memory-safe Rust core with bindings for every language.