Glossary of IoT Terms: LoRaWAN, NB-IoT & LTE

Adaptive Data Rate (ADR)

When adaptive data rate is enabled, the data rate and transmit power are automatically adjusted until optimal performance settings are found. This helps minimise power consumption while maintaining link reliability. ADR is controlled by the end-device and is recommended for static nodes.

Application Key (AppKey)

A 128-bit secret shared between the end-device and the application server, used to derive session keys during activation. Typically displayed as a 32-digit hexadecimal number, it must be entered when registering a new node on the Telemetry2U platform.

Application Server

The top layer in the LoRaWAN stack that handles encryption/decryption and formatting of device data. Telemetry2U’s application server sits between the network server and the user interface.

Bandwidth

The frequency range used for transmission. LoRa supports 125 kHz, 250 kHz, and 500 kHz bandwidths. Higher bandwidth allows faster transmission but reduces range.

Channel Plan

A regional configuration defining supported data rates and frequencies. Telemetry2U supports plans such as AU915, EU868, AS923 variants, and more. The device’s plan must match its profile on the platform.

Class A Device

The most common device class for low-power operation. It only receives downlinks after sending an uplink, allowing it to remain in deep sleep most of the time.

Class B Device

Adds scheduled receive windows using gateway beacons. Increases downlink opportunities but requires time synchronisation. Not supported by Telemetry2U.

Class C Device

Devices continuously listen for downlink messages, except when transmitting. Provides low-latency communication at the cost of higher power usage. Suitable for externally powered nodes.

Data Rate (DR)

Transmission speed, influenced by spreading factor and bandwidth. For AU915, DR0 is 980 bps, and DR13 is up to 21,900 bps. Lower data rates may require improved antenna placement or additional gateways.

Device EUI (DevEUI)

A globally unique identifier assigned to each end device. Required for node registration.

Downlink

Messages sent from the network/server to the end device.

Frame Counter (FCnt)

A sequential count of uplinks and downlinks that helps prevent replay attacks and duplication. Messages with unexpected counters are discarded.

Gateway

A hardware device with a LoRa transceiver that forwards messages between nodes and the network server. Communications to the network server occur over the Internet via Ethernet or Wi-Fi.

Gateway EUI

A unique identifier assigned to each gateway. Required for gateway registration.

LoRa

Short for “Long Range”, LoRa is the modulation technique used for low-power, long-range radio communication. It uses Chirp Spread Spectrum (CSS) technology. See also LoRaWAN for wide-area networking capabilities.

LoRaWAN

An open protocol that builds on LoRa to create a wide-area network, adding layers for device authentication, security, and routing.

Network ID

A unique identifier used to distinguish a LoRaWAN network from others.

Network Server

Manages communication between gateways and the application server. Handles authentication, deduplication, downlink selection, and ADR commands. Telemetry2U provides its own managed network server.

Node

Also called a device or sensor, a node is an end device in a LoRaWAN or IoT network. “Node” helps differentiate from product models.

Over-the-Air Activation (OTAA)

The preferred method of network join. Devices use their DevEUI and AppKey to securely generate session keys during the join process. OTAA is the only supported method on Telemetry2U.

Payload

The actual sensor or command data transmitted in a single message. Payload size is limited and depends on the current data rate.

Port

A one-byte field in each message, often used to distinguish between different data formats or message types.

Profile

Defines the channel plan and class settings for a device on Telemetry2U. For example, AU915 and AU915-C refer to Class A and Class C devices, respectively.

Received Signal Strength Indicator (RSSI)

Measures the strength of received signals in decibels. LoRa RSSI values are negative, typically ranging from -50 (strong) to -130 (weak). Below -110, consider improving antenna setup or adding a gateway.

Spreading Factor (SF)

Determines how long each bit is spread out during transmission. Higher SF means better range but slower data rates and more battery usage.

Sub-Bands

LoRaWAN channel plans are divided into sub-bands. For example, AU915 is split into 8 sub-bands. Gateways and nodes must be aligned on the same sub-band.

Uplink

Messages sent from the end device to the network server or application.

Access Point Name (APN)

A configuration setting on a mobile device that identifies the external network it connects to over cellular infrastructure. Essential for NB-IoT and LTE devices to access the internet.

Carrier Aggregation

A technique in LTE-Advanced that combines multiple frequency bands to increase total bandwidth and data throughput.

Cat-M1 (LTE-M)

A category of LTE designed for IoT. Offers moderate data rates, support for voice (VoLTE), mobility, and power-saving features.

Coverage Enhancement

Used in NB-IoT and LTE-M to improve signal reliability in poor coverage areas like basements or remote sites.

Extended Discontinuous Reception (eDRX)

Allows devices to sleep for extended periods, reducing power consumption while remaining reachable for incoming data.

Half-Duplex Communication

Transmission and reception occur alternately, not at the same time. Often used in NB-IoT to conserve battery life.

In-Band Operation

An NB-IoT deployment mode where the network shares the LTE carrier’s existing frequency allocation.

Latency

The time delay between data transmission and reception. NB-IoT typically has higher latency than LTE-M, making it better for non-time-sensitive applications.

Modulation Techniques

NB-IoT uses SC-FDMA for uplink and OFDMA for downlink. These techniques help balance range, energy efficiency, and reliability.

Power Saving Mode (PSM)

A sleep mode where the device retains its network registration but becomes unreachable, significantly extending battery life.

Quality of Service (QoS)

A measure of service reliability and performance, including delay, jitter, and throughput. LTE-M supports higher QoS than NB-IoT.

Release 13

The 3GPP standard that introduced both NB-IoT and LTE-M to support low-power wide-area network (LPWAN) use cases, including smart metering, tracking, and remote monitoring.

Single Carrier Frequency Division Multiple Access (SC-FDMA)

A modulation technique used for uplink in LTE and NB-IoT. SC-FDMA offers reduced power consumption, helping improve device battery life.

Voice over LTE (VoLTE)

A technology that allows voice calls over LTE networks. Supported by LTE-M, enabling voice functionality without separate channels.