Struct LinkBudget 

pub struct LinkBudget {
    pub transmit_power_dbm: Decibels,
    pub transmit_antenna_gain_dbi: Decibels,
    pub transmit_cable_loss_db: Decibels,
    pub receive_antenna_gain_dbi: Decibels,
    pub receive_cable_loss_db: Decibels,
    pub noise_figure_db: Decibels,
}

The gains and losses of a link, from the transmitting radio to the receiving one.

The fields are the parts of a deployment a maker chooses: how hard the radio drives, which antenna goes on each end, and how much cable sits between each antenna and its radio. The methods add them up against a path and a receiver. The default is 0 dBm between two isotropic antennas with no cable, heard with RADIO_NOISE_FIGURE_DB.

Examples

use pamoja_lora::budget::{Decibels, LinkBudget};

// 14 dBm into a 2.15 dBi antenna through half a decibel of pigtail.
let budget = LinkBudget {
    transmit_power_dbm: Decibels::from_db(14),
    transmit_antenna_gain_dbi: Decibels::from_hundredths(215),
    transmit_cable_loss_db: Decibels::from_tenths(5),
    ..LinkBudget::default()
};
assert_eq!(budget.eirp_dbm().to_string(), "15.65");

// Under a 16 dBm EIRP ceiling, that antenna and cable leave 14.35 dBm for the radio.
let most = budget.max_transmit_power_dbm(Decibels::from_db(16));
assert_eq!(most.to_string(), "14.35");

Fields

transmit_power_dbm: Decibels

The power the transmitting radio delivers at its antenna port, in dBm.

transmit_antenna_gain_dbi: Decibels

The gain of the transmitting antenna over an isotropic antenna, in dBi.

transmit_cable_loss_db: Decibels

The loss in the cable and connectors between the transmitting radio and its antenna, in dB.

receive_antenna_gain_dbi: Decibels

The gain of the receiving antenna over an isotropic antenna, in dBi.

receive_cable_loss_db: Decibels

The loss in the cable and connectors between the receiving antenna and its radio, in dB.

noise_figure_db: Decibels

The noise figure of the receiver, in dB, such as RADIO_NOISE_FIGURE_DB for a node or GATEWAY_NOISE_FIGURE_DB for a gateway.

Implementations

impl LinkBudget

pub fn eirp_dbm(&self) -> Decibels

Returns the equivalent isotropically radiated power, in dBm.

Returns

The transmit power plus the transmitting antenna gain, less the transmitting cable loss. This is the figure regional power ceilings limit.

pub fn received_dbm(&self, path_loss_db: Decibels) -> Decibels

Returns the power that reaches the receiving radio across a path, in dBm.

Arguments

• path_loss_db - the loss between the two antennas, such as free_space_loss_db.

Returns

The EIRP less the path loss, plus the receiving antenna gain, less the receiving cable loss.

pub fn sensitivity_dbm(&self, link: LinkSettings) -> Decibels

Returns the weakest signal the receiver can demodulate on a link, in dBm.

Arguments

• link - the link settings, whose spreading factor and bandwidth set the floor.

Returns

The sensitivity at this budget’s noise figure.

pub fn max_path_loss_db(&self, link: LinkSettings) -> Decibels

Returns the most path loss the link survives, in dB.

Arguments

• link - the link settings, whose spreading factor and bandwidth set the sensitivity.

Returns

How far the power reaching the receiver with no path loss sits above the sensitivity. A path that loses more than this does not close.

pub fn margin_db(&self, link: LinkSettings, path_loss_db: Decibels) -> Decibels

Returns how far above the sensitivity a signal arrives across a path, in dB.

Arguments

• link - the link settings, whose spreading factor and bandwidth set the sensitivity.
• path_loss_db - the loss between the two antennas.

Returns

The link margin, which is negative where the path loses more than the link survives.

pub fn max_transmit_power_dbm(&self, eirp_ceiling_dbm: Decibels) -> Decibels

Returns the most transmit power that keeps the EIRP at or under a ceiling, in dBm.

Arguments

• eirp_ceiling_dbm - the EIRP limit, such as the max_eirp_dbm a channel plan publishes for a frequency.

Returns

The ceiling less the transmitting antenna gain, plus the transmitting cable loss. A higher-gain antenna leaves less power for the radio.

Trait Implementations

impl Clone for LinkBudget

fn clone(&self) -> LinkBudget

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for LinkBudget

impl Debug for LinkBudget

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for LinkBudget

fn default() -> Self

Returns the “default value” for a type.

impl Eq for LinkBudget

impl Hash for LinkBudget

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LinkBudget

fn eq(&self, other: &LinkBudget) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for LinkBudget