@pamoja/lora

Time-on-air, duty-cycle off-time, the regional channel plans a LoRa node must keep to, and the link budget that sets its range. One capability of pamoja, one memory-safe Rust core with bindings for TypeScript, Python, and C#.

Install

npm install @pamoja/lora
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This pulls in @pamoja/native, the compiled engine. npm install pamoja is the whole framework in one package.

Example

The test that runs in CI, spliced here as it ran.

From bindings/node/guides/lora.ts:

import { LoraRegion, airtimeUs, messagesPerHour, minOffTimeUs, planFor } from '@pamoja/lora'

// EU863-870 numbers its data rates from the slowest. DR0 is SF12 at 125 kHz, the setting
// that reaches furthest and holds the channel longest.
const plan = planFor(LoraRegion.Eu868)
const link = plan.linkSettings(0)!
console.log(`${plan.name} DR0 is SF${link.spreadingFactor} at 125 kHz`)

// The time on air for that setting, coding rate 4/5, an eight-symbol preamble, an explicit
// header and CRC on, carrying a ten-byte reading.
const airtime = airtimeUs(link, 10)
console.log(`airtime   ${(airtime / 1e6).toFixed(2)} s for ten bytes`)

// 868.1 MHz falls in a sub-band capped at 1% of the time and 16 dBm, so every transmission
// buys ninety-nine times its own length in silence.
const channel = 868_100_000
const permille = plan.dutyCyclePermille(channel)!
console.log(`channel   ${permille} per mille duty cycle, ${plan.maxEirpDbm(channel)} dBm`)

const offTime = minOffTimeUs(link, 10, permille)!
console.log(`silence   ${(offTime / 1e6).toFixed(1)} s owed after each reading`)

// The airtime plus that silence is what one reading really costs, which is the budget a
// deployment plans against.
console.log(`budget    ${messagesPerHour(link, 10, permille)} readings an hour`)

// A frequency in no sub-band the plan describes has no duty cycle to budget against. That
// is a limit published elsewhere, not permission to transmit.
const outside = plan.dutyCyclePermille(700_000_000)
const elsewhere =
  outside === null
    ? 'in no sub-band of this plan, so its limit is published elsewhere'
    : `limited to ${outside} per mille`
console.log(`700 MHz   ${elsewhere}`)
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The same capability in every language

Documentation

• @pamoja/lora reference, every class, function, and type this package exports.
• The LoRa airtime and range guide, with the same example in Rust, Python, and C#.
• Every capability, and the install page.

License

MIT