Lora wireless technology principle and advantages and disadvantages
1. Introduction to LoRa Wireless Technology
LoRa is a long-distance wireless transmission technology based on spread spectrum technology. It is actually one of many LPWAN communication technologies. It was first adopted and promoted by Semtech in the United States. This solution provides users with a simple means of realizing long-distance, low-power wireless communication. At present, LoRa wireless technology mainly operates in the ISM frequency band, mainly including 433, 868, 915 MHz, etc.
LoRa is the physical layer or wireless modulation used to establish long-distance communication links. Many conventional wireless systems use Frequency Shift Keying (FSK) modulation as the physical layer because it is a very efficient modulation that achieves low power consumption. LoRa® is based on chirp spread spectrum modulation, which maintains the same low power consumption characteristics as FSK modulation, but significantly increases the communication distance. Linear spread spectrum has been used in military and space communications for decades due to its ability to achieve long communication distances and robustness to interference, but LoRa® is the first low-cost implementation for commercial use.
The advantage of LoRa modules is their long-range capability in terms of technology. A single gateway or base station can cover an entire city or hundreds of square kilometers. In a given location, the distance is highly dependent on the environment or obstacles, but LoRa® and LoRaWAN™ have a link budget that is better than any other standardized communication technology. Link budget, usually expressed in decibels (dB), is the primary factor in determining distance in a given environment.
2. The composition of LoRa wireless technology network
The LoRa network is mainly composed of four parts: terminal (with built-in LoRa module), gateway (or base station), server and cloud. Application data can be transferred in both directions.
LoRa Alliance The LoRa Alliance is an open, non-profit organization led by Semtech in March 2015. Its founding members include Actility in France, AUGTEK in China, and Royal Dutch Telecom kpn. In less than a year, the alliance has developed more than 150 member companies, including IBM, Cisco, Orange and other heavyweight manufacturers. There are a large number of enterprises in each link of the industrial chain (terminal hardware manufacturers, chip manufacturers, module gateway manufacturers, software manufacturers, system integrators, network operators), the openness of this technology, competition and cooperation. Adequacy has promoted the rapid development and ecological prosperity of LoRa.
3. Lora network architecture and principle
In a mesh network, individual terminal nodes forward information from other nodes to increase the communication distance of the network and the size of the network area. While this increases range, it also increases complexity, reduces network capacity, and reduces battery life as nodes accept and forward information from other nodes that may not be relevant to them. When implementing long-distance connections, the long-distance star architecture makes the most sense to preserve battery life.
In a LoRaWAN™ network, nodes are not associated with dedicated gateways. Instead, data transmitted by one node is usually received by multiple gateways. Each gateway forwards the received packets from the end node to the cloud-based network server through some backhaul (cellular, ethernet, etc.). Intelligence and sophistication are placed on the server, which manages the network and filters redundant incoming data, performs security checks, schedules confirmation through the optimal gateway, and performs adaptive data rates, etc.
Fourth, the introduction of LoRaWAN protocol
LoRaWAN is a low-power wide area network communication protocol based on the open source MAC layer protocol released by the LoRa Alliance. Provides local, national, or global network communication protocols primarily for battery-powered wireless devices.