What is a LoRa module?

LoRa and LoRaWAN together define a Low Power, Wide Area (LPWA) networking protocol designed to wirelessly connect battery operated ‘things’ to the internet in regional, national or global networks, and targets key Internet of things (IoT) requirements such as bi-directional communication, end-to-end security, mobility and localization services. The low power, low bit rate, and IoT use distinguish this type of network from a wireless WAN that is designed to connect users or businesses, and carry more data, using more power. The LoRaWAN data rate ranges from 0.3 kbit/s to 50 kbit/s per channel.

LoRa (from "long range") is the physical proprietary radio modulation technique. It is based on spread-spectrum modulation techniques derived from chirp spread spectrum (CSS) technology. It was developed by Cycleo (patent 9647718-B2), a company of Grenoble, France, later acquired by Semtech.

LoRaWAN defines the software communication protocol and system architecture. The continued development of the LoRaWAN protocol is managed by the open, non-profit LoRa Alliance, of which SemTech is a founding member.

MultiTech LoRa modules are secure, regulatory-certified, Arm? Mbed? programmable, low-power RF modules, providing long-range, low bit rate IoT data connectivity to sensors and actuators.

What does LoRa stand for?

long range

LoRa (short for long range) is a spread spectrum modulation technique derived from chirp spread spectrum (CSS) technology. Semtech's LoRa is a long range, low power wireless platform that has become the de facto wireless platform of Internet of Things (IoT).

What is the use of LoRa?

LoRa is flexible for rural or indoor use cases in smart agriculture, smart cities, industrial IoT (IIoT), smart environment, smart homes and buildings, smart utilities and metering, and smart supply chain and logistics.

LoRa PHY

LoRa uses a proprietary spread spectrum modulation that is similar to and a derivative of chirp spread spectrum (CSS) modulation. The spread spectrum LoRa modulation is performed by representing each bit of payload information by multiple chirps of information. The rate at which the spread information is sent is referred to as the symbol rate, the ratio between the nominal symbol rate and chirp rate is the spreading factor (SF) and represents the number of symbols sent per bit of information.[3] The result is an M-ary digital modulation,

where the {displaystyle M=2^{SF}} possible waveforms at the output of the modulator are chirp modulated signals over the frequency interval ({\displaystyle f_{0}-B/2,f_{0}+B/2}) with M different initial frequencies: the instantaneous frequency is linearly increased, and then wrapped to {\displaystyle f_{0}-B/2} when it reaches the maximum frequency {\displaystyle f_{0}+B/2}.

LoRa can trade off data rate for sensitivity with a fixed channel bandwidth by selecting the amount of spread used (a selectable radio parameter from 6 to 12 [12]). Lower SF means more chirps are sent per second; hence, you can encode more data per second. Higher SF implies fewer chirps per second; hence, there are fewer data to encode per second. Compared to lower SF, sending the same amount of data with higher SF needs more transmission time, known as airtime. More airtime means that the modem is up and running longer and consuming more energy. The benefit of high SF is that more extended airtime gives the receiver more opportunities to sample the signal power, which results in better sensitivity.

The LoRa modem allows changing of the transmission power from 2dBm to 14dBm (433 MHz) or as high as 20dBm (865 MHz to 867 MHz, 915 MHz, and 923 MHz) as per the regulations of each country. Higher transmission power gives the receiver better signal power and better sensitivity, but at the cost of consuming more energy. There are measurement studies of LoRa performance with regard to energy consumption, communication distances, and medium access efficiency.

 According to the LoRa Development Portal, the range provided by LoRa can be up to three miles (five kilometers) in urban areas, and up to 10 miles (15 kilometers) or more in rural areas (line of sight).

In addition, LoRa uses forward error correction coding to improve resilience against interference. LoRa's high range is characterized by high wireless link budgets of around 155 dB to 170 dB.[16] Range extenders for LoRa are called LoRaX.

What is difference between LoRa and WiFi?

Residential Connectivity: Wi-Fi is used to connect billions of personal and professional devices in homes, while LoRaWAN is used for home security and access control, leak detection, and fuel tank monitoring, and many other applications.

LoRaWAN

Since LoRa defines the lower physical layer, the upper networking layers were lacking. LoRaWAN is one of several protocols that were developed to define the upper layers of the network. LoRaWAN is a cloud-based medium access control (MAC) layer protocol, but acts mainly as a network layer protocol for managing communication between LPWAN gateways and end-node devices as a routing protocol, maintained by the LoRa Alliance.

LoRaWAN defines the communication protocol and system architecture for the network, while the LoRa physical layer enables the long-range communication link. LoRaWAN is also responsible for managing the communication frequencies, data rate, and power for all devices.

Devices in the network are asynchronous and transmit when they have data available to send. Data transmitted by an end-node device are received by multiple gateways, which forward the data packets to a centralized network server.

Data are then forwarded to application servers.

 The technology shows high reliability for the moderate load, however, it has some performance issues related to sending acknowledgements

LoRa devices and the LoRaWAN standard offer compelling features for IoT applications including long range, low power consumption and secure data transmission. The technology is utilized by public, private or hybrid networks and provides greater range than Cellular networks. Deployments can easily integrate into existing infrastructure and enable low-cost battery-operated IoT applications. Semtech's LoRa chipsets are incorporated into devices manufactured by a large ecosystem of IoT solution providers, and connected to networks around the globe. Simply stated, LoRa connects devices to the Cloud, providing a "voice" to things — making the world a better place to live, work and play. 

LoRa Modules

Semtech corporation is the leader in LoRa wireless technology and as such have introduced a number of LoRa RF modules for the market. In particular, the SX127x family of RF transceivers for the IoT/M2M markets.

These RF modules operated between 860-1000 MHz and 137-960MHz. Semtech also offer evaluation and testing devices at 860MHz band.

Adafruit has recently introduced a number of breakout boards and development boards based around the Semtech RFM69 and RFM95 modules for a range of frequencies such as 433, 868 and 960 MHz.

These are +20dBm LoRa packet radios that have a special radio modulation that is not compatible with the RFM69s but can go much farther. They can easily go 2 Km (1.24 mi) line of sight using simple wire antennas, or up to 20Km (12.4 mi) with directional antennas and settings tweaking’s.

Packet radio with ready-to-go Arduino libraries

Uses the license-free ISM band: "European ISM" @ 868MHz or "American ISM" @ 915MHz

Use a simple wire antenna or spot for uFL or SMA radio connector

SX1276 LoRa? based module with SPI interface

+5 to +20 dBm up to 100 mW Power Output Capability (power output selectable in software)

~100mA peak during +20dBm transmit, ~30mA during active radio listening.

Range of approx. 2Km (1.24 mi), depending on obstructions, frequency, antenna and power output

Each radio comes with some header, a 3.3V voltage regulator and level shifter that can handle 3-5V DC power and logic so you can use it with 3V or 5V devices. Some soldering is required to attach the header. You will need to cut and solder on a small piece of wire (any solid or stranded core is fine) in order to create your antenna. Optionally you can pick up a uFL or SMA edge-mount connector and attach an external duck.

MicroChip, also being a key partner in the LoRa Alliance have also introduced a number of LoRa modules for the IoT market. The module is a small form factor with up to 14 GPIO pins for connecting sensors and actuators whilst taking up very little space.

"The RN2483 module is a revolutionary end-node IoT solution for the new LoRa technology network, enabling extremely long-range, bidirectional communication with significant battery life," said Steve Caldwell, vice president of Microchip's Wireless Products Division. "As a founding member of the LoRa Alliance, we are working to ensure our modules are compatible with all partner gateways and back-end network service providers."

The RN2483 comes with the LoRaWAN? protocol stack, so it can easily connect with the established and rapidly expanding LoRa Alliance infrastructure—including both privately managed local area networks (LANs) and telecom-operated public networks—to create Low Power Wide Area Networks (LPWANs) with nationwide coverage. This stack integration also enables the module to be used with any microcontroller that has a UART interface, including hundreds of Microchip's PIC? MCUs. Additionally, the RN2483 features Microchip's simple ASCII command interface for easy configuration and control.

With its scalability, robust communication, mobility and the ability to operate in harsh outdoor environments, the RN2483 is well suited for a broad range of low-data-rate wireless monitoring and control designs.