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configurability.md

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Configurability

Set sampling interval and logic from cloud

The Asset Tracker can be configured remotely through nRF Cloud's device shadow mechanism. This allows dynamic adjustment of device behavior without requiring firmware updates.

Configuration through nRF Cloud UI

  1. Log in to nRF Cloud
  2. Navigate to "Devices" and select your device
  3. Click on "View Config" in the top bar
  4. Select "Edit Configuration"
  5. Enter the desired configuration:
{
  "update_interval": 60
}
  1. Click "Commit" to apply the changes

The device will receive the new configuration through its shadow and adjust its update interval accordingly.

Configuration Flow

  1. Initial Setup

    • Device starts with default interval from CONFIG_APP_MODULE_TRIGGER_TIMEOUT_SECONDS
    • Upon cloud connection, device automatically requests shadow configuration

  2. Runtime Configuration

    • Cloud module receives and processes shadow updates
    • Device maintains last known configuration during offline periods

  3. Impact on Device Behavior The update_interval configuration controls the frequency of:

    • Location updates
    • Sensor sampling (environmental, battery, network quality)
    • FOTA update checks
    • Shadow update polling

Set location method priorities

The Asset Tracker supports multiple location methods that can be prioritized based on your needs. Configuration is done through board-specific configuration files.

Available Location Methods

  • GNSS (GPS)
  • Wi-Fi positioning
  • Cellular positioning

Configuration Examples

  1. Thingy91x Configuration (wifi available):
CONFIG_LOCATION_REQUEST_DEFAULT_METHOD_FIRST_WIFI=y
CONFIG_LOCATION_REQUEST_DEFAULT_METHOD_SECOND_GNSS=y
CONFIG_LOCATION_REQUEST_DEFAULT_METHOD_THIRD_CELLULAR=y
CONFIG_LOCATION_REQUEST_DEFAULT_WIFI_TIMEOUT=10000
  1. nRF9151 DK Configuration (wifi unavailable):
CONFIG_LOCATION_REQUEST_DEFAULT_METHOD_FIRST_GNSS=y
CONFIG_LOCATION_REQUEST_DEFAULT_METHOD_SECOND_CELLULAR=y

Network configuration

NB-IoT vs LTE-M

The Asset Tracker supports both LTE Cat NB1 (NB-IoT) and LTE Cat M1 (LTE-M) cellular connectivity:

  • NB-IoT: Optimized for:

    • Low data rate applications
    • Better coverage
    • Stationary or low-mobility devices

  • LTE-M: Better suited for:

    • Higher data rates
    • Mobile applications
    • Lower latency requirements

Network Mode Selection

The following network modes are available (LTE_NETWORK_MODE):

  • Default: Use the system mode currently set in the modem
  • LTE-M: LTE Cat M1 only
  • LTE-M and GPS: LTE Cat M1 with GPS enabled
  • NB-IoT: NB-IoT only
  • NB-IoT and GPS: NB-IoT with GPS enabled
  • LTE-M and NB-IoT: Both LTE-M and NB-IoT enabled
  • LTE-M, NB-IoT and GPS: Both LTE modes with GPS enabled

Network Mode Preference

When multiple network modes are enabled (LTE-M and NB-IoT), you can set preferences (LTE_MODE_PREFERENCE):

  • No preference: Automatically selected by the modem
  • LTE-M: Prioritize LTE-M over PLMN selection
  • NB-IoT: Prioritize NB-IoT over PLMN selection
  • LTE-M, PLMN prioritized: Prefer LTE-M but prioritize staying on home network
  • NB-IoT, PLMN prioritized: Prefer NB-IoT but prioritize staying on home network

Example configuration in prj.conf:

# Enable both LTE-M and NB-IoT with GPS
CONFIG_LTE_NETWORK_MODE_LTE_M_NBIOT_GPS=y

# Prefer LTE-M while prioritizing home network
CONFIG_LTE_MODE_PREFERENCE_LTE_M_PLMN_PRIO=y

PSM (Power Saving Mode)

PSM allows the device to enter deep sleep while maintaining network registration. Configuration is done through Kconfig options:

PSM Parameters

  1. Periodic TAU (Tracking Area Update)

    • Controls how often the device updates its location with the network
    • Configuration options: 
      # Configure TAU in seconds
CONFIG_LTE_PSM_REQ_RPTAU_SECONDS=1800  # 30 minutes

  2. Active Time (RAT)

    • Defines how long the device stays active after a wake-up
    • Configuration options: 
      # Configure RAT in seconds
CONFIG_LTE_PSM_REQ_RAT_SECONDS=60  # 1 minute

Key aspects:

  • Device negotiates PSM parameters with the network
  • Helps achieve longer battery life
  • Device remains registered but unreachable during sleep
  • Wakes up periodically based on TAU setting
  • Stays active for the duration specified by RAT

APN (Access Point Name)

The Access Point Name (APN) is a network identifier used by the device to connect to the cellular network's packet data network. Configuration options:

  • Default APN: Most carriers automatically configure the correct APN
  • Manual Configuration: If needed, APN can be configured through Kconfig: 
    CONFIG_PDN_DEFAULT_APN="Access point name"

Common scenarios for APN configuration:

  • Using a custom/private APN
  • Connecting to specific network services
  • Working with MVNOs (Mobile Virtual Network Operators)

Note: In most cases, the default APN provided by the carrier should work without additional configuration.