Introduction:
LoRa devices and wireless radio frequency technology are a long-distance, low-power IoT solution that has been widely adopted in recent years. This technology supports telecommunications companies, IoT application developers and system integrators to deploy low-cost and interoperable devices around the world. IoT networks, gateways, sensors, module products and IoT services, and provide the required feature set. This article starts from the principle of LoRa technology, describes the technical concept and summarizes its technical characteristics, and introduces the current application methods of LoRa technology in many fields, as well as the development process of this technology at home and abroad in recent years.
Engels:
LoRa devices and radio frequency technology are long-range, low-power Internet of Things (“IoT”) solutions that have been widely adopted in recent years. This technology enables telecom companies, IoT application developers and system integrators to deploy low-cost and globally interoperable IoT networks, gateways, sensors, module products, and IoT services, and provide the required combination of features. This paper begins with the principles of LoRa technology, describes the technical concepts and summarizes its technical characteristics, and introduces the application of LoRa technology in many fields at the present stage, as well as the development process of this technology in China and abroad in recent years ．
LoRa technology principle
1.1 LoRa technical concept
There are many wireless technologies in IoT applications, which can be divided into two categories in terms of transmission distance. One is short-distance communication technology, including ZigBee, Wi-Fi, Bluetooth, etc.; the other is long-distance wireless communication technology, including Wireless Wide Area Networks (WWAN) and Low Power Wide Area Networks (LPWAN), etc. Low-power wide area network technology is a revolutionary Internet of Things access technology in the world in recent years, and LoRa belongs to this technology field.
LoRa is based on linear frequency modulation spread spectrum modulation, which maintains the same low-power characteristics as FSK modulation and significantly increases the communication distance. It changes the previous trade-off considerations about transmission distance and power consumption, and provides users with a simple way to achieve long-distance, Long battery life, high-capacity systems to expand sensor networks. LoRa mainly operates in free frequency bands around the world (i.e. unlicensed frequency bands), including 433, 868, 915 MHz, etc. The LoRa network is mainly composed of terminals (built-in LoRa modules), gateways (or base stations), application servers and cloud storage. Application data can be transmitted in both directions.
LoRaWAN (LoRa Wide-Area Networks) defines the communication protocol and system architecture, stipulates the end-to-end standard specifications for the use of LoRa technology, including IoT market security, energy efficiency, roaming and configuration on-boarding (on-boarding), etc., and is the LoRa Alliance Norms for members.
1.2LoRa technical features
(1) Large communication range The advantage of LoRa lies in the long-distance communication capability of this technology. It is based on linear frequency modulation spread spectrum modulation. It maintains the same low power consumption characteristics as FSK modulation, but significantly increases the communication distance, which is up to A link budget of 157 db enables communication distances up to 15 km, and a single gateway or base station can cover hundreds of square kilometers (coverage depends largely on the surrounding environment or obstacles). The Proximus network deployed in Belgium covers most of the country with only a minimal amount of infrastructure.
(2) Low power consumption/long battery life LoRa is one of the low-power wide area network communication technologies. It is a physical layer or wireless modulation used to establish long-distance communication links. Its receiving current is only 10 mA and its sleep current is 200 nA, which greatly extends the battery life. Many legacy wireless systems use frequency shift keying (FSK) modulation as the physical layer because it is a very efficient modulation that achieves low power consumption. Nodes in a LoRaWAN network are asynchronous and communicate when data is ready to be sent, whether event-driven or scheduled. In the GSMA’s recent research and comparison of various technologies in the LPWAN field, LoRaWAN showed a 3 to 5 times advantage in power consumption performance compared to all other technology options.
(3) Strong anti-interference LoRa technology itself has ultra-high receiving sensitivity (RSSI) and ultra-strong signal-to-noise ratio (SNR). It uses frequency hopping technology and performs frequency shift keying through pseudo-random code sequences to make the carrier frequency continuously jump. Change and spread the spectrum to prevent fixed frequency interference. Terminals with different spreading sequences will not interfere with each other even if they use the same frequency to transmit at the same time. Therefore, the concentrator/Gateway developed on this basis can receive and process data from multiple nodes in parallel, greatly expanding the system. capacity.
capacity.
(4) Large network capacity. In order to make the remote star network available, the gateway must have a very high capacity or ability to receive messages from a large number of nodes. A large-capacity base station based on LoRa can support millions of messages per day, and a single base station Can support thousands of devices. High network capacity in LoRaWAN networks is achieved at the gateway by leveraging adaptive data rates and using multi-channel multi-modem transceivers to receive messages on multiple channels simultaneously.
(5) Low-cost license-free frequency bands, low infrastructure costs, and low node/terminal costs make the link costs of LoRa and LoRaWAN less than any other standardized communication technology. Linear spread spectrum has been used in military and space communications for decades because it enables long communication ranges and robustness to interference, and LoRa is the first low-cost implementation for commercial use.
(6) High network security Security is very important for any LPWAN. LoRaWAN can protect data and privacy very well. It is the most secure solution in the LPWAN field on the market. 128AES encryption. All data from sensors to application servers and backend are encrypted at multiple levels. LoRaWAN uses two layers of security: one for the network and another for the application. Network security ensures the authenticity of nodes in the network, while the secure application layer ensures that network operators cannot access end-user application data. AES encryption is used with key exchange using the IEEE EUI64 identifier.
(7) The technical ecosystem is improved. LoRaWAN has multiple business models, reasonable competition, a diversified ecosystem, and industry leaders, which greatly promotes its expansion and rapid implementation. At the same time, LoRa’s use of open standards and proprietary technology is also a guarantee for its recognition and widespread deployment. The selection of various network components, gateways, end devices, cloud network servers and chips, development kits and end products come from many different vendors to provide different solutions for operators or end users.
Trefwoorden: lora