Cycleo, a part of Semtech since 2012, has developed and patented a physical layer with a modulation type, with the name LoRA or Long Range, where the transmission utilizes the license-free ISM bands. LoRa consumes very low power and is therefore, ideal for IoT for data transmission. Sensor technology is one possible field of application for LoRa, where low bit rates are sufficient, and where the sensor batteries last for months or even years. Other applications are in the industry, environment technology, logistics, smart cities, agriculture, consumption recording, smart homes, and many others.
LoRa uses wireless transmission technology, and consumes very low power to transmit small amounts of data over distances of nearly 15 Km. It uses CSS or Chirp Spread Spectrum modulation, originally meant for radar applications, and developed in the 1940s, with chirp standing for Compressed High Intensity Radar Pulse. The name suggests the manner of data transmission by this method.
Many current wireless data transmission applications use the LoRa method, owing to its relative low power consumption, and its robustness against fading, in-band spurious emissions, and Doppler effect. IEEE has taken up the CSS PHY as a standard 802.15.4a for use as low-rate wireless personal area networks.
A correlation mechanism, based on band spreading methods, makes it possible for LoRa to achieve the long ranges. This mechanism permits use of extremely small signals that can disappear in noise. De-spreading allows modulation of these small signals in the transmitter. LoRa receivers are sensitive enough to decode these signals, even when they are more than 19 dB below the noise levels. Unlike the DSSS or direct sequence spread spectrum that the UMTS or WLAN uses, CSS makes use of chirp pulses for frequency spreading rather than using the pseudo-random code sequences.
A chirp pulse, modulated by GFSK or FM, usually has a sine-wave signal characteristic along with a constant envelope. As time passes, this characteristic falls or rises continuously in frequency. That makes the frequency bandwidth of the pulse equivalent to the spectral bandwidth of the signal. CSS uses the signal characteristic as a transmit pulse.
Engineers use LoRaWAN to define the MAC or media access protocol and the architecture of the system for a WAN or wide area network. The special design of LoRaWAN especially targets IoT devices requiring energy efficiency and high transmission range. Additionally, the protocol makes it easier for communications with server-based internet applications.
The architecture of the LoRaWAN MAC is suitable for LoRa devices, because of its influence on their battery life, the network capacity, the service quality, and the level of security it offers. Additionally, it has a number of applications as well.
The LoRa Alliance, a standardization body, defines, develops, and manages the regional factors and the LoRa waveform in the LoRaWAN stack for interaction between the LoRa MAC. The standardization body consists of software companies, semiconductor companies, manufacturers of wireless modules and sensors, mobile network operators, testing institutions, and IT companies, all working towards a harmonized standard for LoRaWAN. Using the wireless technology of LoRa, users can create wireless networks covering an area of several square kilometer using only one single radio cell.