Glossary of LoRaWAN, NB-IoT and LTE-M Terms
Clear definitions of the radio, network, security and power-management terms commonly used when deploying wireless sensors with Telemetry2U.
Understanding Wireless IoT Terminology
This glossary explains terms used throughout Telemetry2U documentation, device configuration screens and network troubleshooting guides.
LoRaWAN, NB-IoT and LTE-M are all low-power wide-area networking technologies, but they use different radio infrastructure and network architectures. The first section covers LoRaWAN and LoRa radio concepts. The second covers cellular IoT terms used by NB-IoT and LTE-M devices.
Platform-specific definitions: Terms such as Profile, supported device classes and activation methods describe how those settings are used within Telemetry2U. Hardware and other network servers may support additional options.
LoRa and LoRaWAN Terms
Adaptive Data Rate (ADR)
A LoRaWAN mechanism that allows the network to optimise an end device's data rate and transmit power. ADR can reduce airtime and energy use while maintaining a reliable link, and is generally most suitable for devices in fixed locations.
Application Key (AppKey)
A 128-bit secret used during Over-the-Air Activation to authenticate a device and derive session keys. It is normally represented as 32 hexadecimal characters and must be protected from unauthorised access.
Application Server
The part of a LoRaWAN system that receives application payloads, decrypts or decodes device data and makes the resulting measurements available to users or other software. Telemetry2U provides the application layer used for dashboards, alerts, reports and device control.
Bandwidth
The width of the radio channel used for a transmission. Common LoRa bandwidths include 125 kHz, 250 kHz and 500 kHz. A wider bandwidth can support a higher data rate, while a narrower bandwidth generally provides greater receiver sensitivity.
Channel Plan or Frequency Plan
The regional set of radio frequencies, data rates and channel rules used by a LoRaWAN device. Examples include AU915, EU868 and the AS923 variants. The end device, gateway and Telemetry2U profile must use compatible settings.
Class A Device
The mandatory and lowest-power LoRaWAN device class. Each uplink is followed by two short receive windows in which the network may send a downlink. At other times, the device can remain asleep.
Class B Device
A device class that adds scheduled receive windows, called ping slots, which are synchronised using network beacons. This provides more predictable downlink timing than Class A but increases power consumption. Class B is not currently supported by Telemetry2U.
Class C Device
A device class that keeps its receiver open whenever it is not transmitting. This provides the lowest downlink latency but consumes substantially more power, so Class C is normally used with externally powered devices.
Data Rate (DR)
A numbered LoRaWAN setting that determines the modulation parameters and transmission speed. Lower data rates are slower but can provide a more robust link. Higher data rates shorten airtime but require a stronger radio connection.
Device EUI (DevEUI)
A globally unique 64-bit identifier assigned to a LoRaWAN end device. The DevEUI is normally written as 16 hexadecimal characters and is required when registering a device for OTAA.
Downlink
A message sent from the network towards an end device. Downlinks may contain configuration changes, control commands, acknowledgements or application data.
Frame Counter (FCnt)
A sequential counter included in LoRaWAN data frames. Separate uplink and downlink counters help detect duplicate messages and protect against replay attacks. Unexpected counter values can cause a network server to reject a frame.
Gateway
A device that receives LoRa radio packets from nearby end devices and forwards them to a LoRaWAN network server over an Internet connection such as Ethernet, Wi-Fi or cellular. A gateway does not normally decode the application payload.
Gateway EUI
A unique 64-bit identifier used to register and distinguish a LoRaWAN gateway. It is commonly displayed as 16 hexadecimal characters.
LoRa
The long-range radio modulation used by LoRaWAN. LoRa uses Chirp Spread Spectrum modulation to support low-power communication over long distances. LoRa defines the radio link; LoRaWAN defines the networking protocol that operates above it.
LoRaWAN
An open low-power wide-area network protocol maintained by the LoRa Alliance. It defines device activation, message formats, security, network architecture, regional parameters and communication classes for devices using LoRa radios.
Low-Power Wide-Area Network (LPWAN)
A category of wireless network designed to connect devices over long distances while using little power and transmitting relatively small amounts of data. LoRaWAN, NB-IoT and LTE-M are LPWAN technologies.
Network ID (NetID)
An identifier associated with a LoRaWAN network. It helps distinguish network operators and contributes to the addressing information assigned to joined devices.
Network Server
The LoRaWAN component that manages communication between gateways and application servers. It performs functions such as frame validation, duplicate removal, Adaptive Data Rate control and selection of a gateway for downlinks.
Node or End Device
A sensor, controller, meter or other field device that communicates through the IoT network. In LoRaWAN documentation, end device is the formal term, while node is commonly used as a shorter equivalent.
Over-the-Air Activation (OTAA)
A LoRaWAN join method in which a device authenticates with the network and receives session parameters dynamically. OTAA supports fresh session keys after a successful join and is the activation method supported by Telemetry2U.
Payload
The application data carried inside a message, such as temperature readings, battery voltage or a control command. LoRaWAN payload capacity depends on the regional plan, data rate and protocol overhead.
Port (FPort)
A one-byte LoRaWAN field used to identify the purpose or format of a frame payload. Device manufacturers often use different FPort values for measurements, configuration messages and diagnostic data.
Profile
A Telemetry2U configuration that defines the regional channel plan and supported device class. For example, an AU915 profile is used for a Class A device, while an AU915-C profile identifies a Class C device.
Received Signal Strength Indicator (RSSI)
An estimate of the received radio signal power, normally reported in dBm. LoRa RSSI values are usually negative; a value closer to zero represents a stronger received signal. RSSI should be assessed together with SNR, packet reliability, antenna placement and the local radio environment.
Signal-to-Noise Ratio (SNR)
The difference between the wanted signal level and the background noise level, measured in decibels. LoRa can often decode packets with a negative SNR, but a higher value generally indicates a healthier radio link.
Spreading Factor (SF)
A LoRa modulation setting that affects receiver sensitivity, data rate and airtime. A higher spreading factor can improve reception of weak signals but increases transmission time and energy used per message.
Sub-Band
A group of channels within a larger regional frequency plan. AU915 and US915 use multiple channel groups, and gateways and end devices must be configured to use compatible channels for reliable communication.
Uplink
A message sent from an end device towards the network server and application. Sensor measurements and device status reports are normally carried in uplinks.
NB-IoT and LTE-M Terms
Access Point Name (APN)
A cellular network setting that identifies the packet-data service or private network a device should use. The APN must match the SIM provider's requirements before an NB-IoT or LTE-M modem can establish an IP data connection.
Carrier Aggregation
An LTE-Advanced technique that combines multiple radio carriers to increase bandwidth and throughput. It is primarily associated with higher-rate LTE services rather than the narrowband operation used by typical NB-IoT devices.
Coverage Enhancement
Cellular IoT techniques that repeat transmissions or use more robust radio settings to improve communication in difficult locations. Coverage enhancement can increase reliability but also increases latency, airtime and energy use.
Extended Discontinuous Reception (eDRX)
A cellular power-saving feature that allows a device to check less frequently for incoming network traffic. Longer eDRX cycles can extend battery life while keeping the device periodically reachable for downlink communication.
Half-Duplex Communication
A communication method in which transmission and reception do not occur at the same time. Half-duplex operation reduces modem complexity and is used by many low-power cellular IoT devices.
In-Band Operation
An NB-IoT deployment mode that places the narrowband carrier inside an operator's existing LTE channel. Other deployment options include guard-band and standalone operation.
Latency
The delay between sending data and receiving the expected response. Cellular IoT latency varies with coverage, network configuration and power-saving settings. LTE-M usually supports lower latency than NB-IoT.
Long Term Evolution (LTE)
The 3GPP mobile broadband technology commonly known as 4G. LTE provides the network foundation from which the LTE-M and NB-IoT cellular IoT technologies were developed.
LTE-M or Cat-M1
A low-power LTE category designed for machine-type communication. LTE-M supports mobility, relatively low latency, power-saving features and higher data rates than NB-IoT. Network support can also include Voice over LTE.
Narrowband Internet of Things (NB-IoT)
A 3GPP cellular LPWAN technology designed for low-cost devices that send small amounts of data. NB-IoT prioritises coverage, capacity and low power consumption over mobility, throughput and low latency.
Orthogonal Frequency Division Multiple Access (OFDMA)
A radio access technique that divides available bandwidth into many closely spaced subcarriers. LTE and NB-IoT use OFDMA for downlink transmission.
Power Saving Mode (PSM)
A cellular sleep state in which a device remains registered with the network but is not reachable for downlinks. The modem can consume very little power until its next scheduled update or application-triggered wake-up.
Quality of Service (QoS)
Network mechanisms and performance characteristics associated with factors such as priority, delay, reliability and throughput. The available QoS depends on the cellular technology, operator and subscribed service.
3GPP Release 13
The 3GPP standards release that introduced NB-IoT and LTE-M as cellular technologies for low-power machine-type communication. Later releases have added further coverage, positioning, power and mobility enhancements.
Single-Carrier Frequency Division Multiple Access (SC-FDMA)
A radio access technique used for LTE-family uplink transmission. Its relatively low peak-to-average power ratio helps reduce transmitter power requirements in mobile and IoT devices.
Voice over LTE (VoLTE)
A standards-based method for carrying voice calls over an LTE packet network. LTE-M can support VoLTE where the modem, subscription and mobile network provide the required capability.