This scheme changes the previous compromise between transmission distance and power consumption, and provides users with a simple system that can realize long distance, long battery life and large capacity, thus expanding the sensor network. LoRa technology has the characteristics of long distance, low power consumption (long battery life), multi-node and low cost.
LoRa is widely deployed in smart communities, smart homes and buildings, smart meters, smart agriculture, smart logistics and other vertical industries because of its low power consumption, long transmission distance and flexible networking, which well meets the needs of fragmentation, low cost and large connection of the Internet of Things.
Overview of LoRa's characteristics:
1. Transmission distance: 2-5Km in town and 15Km in suburb.
2. Operating frequency: ISM frequency band includes 433, 868, 9 15MH, etc.
3. Standard: IEEE 802.15.4g.
4. Modulation mode: Based on spread spectrum technology, it is a variant of linear modulation spread spectrum (CSS) with forward error correction (FEC) capability, and it is the proprietary technology of semtech.
5. Capacity: One LoRa gateway can connect thousands of LoRa nodes.
6. Battery life: up to 10 year.
7. Security: AES 128 encryption.
8. Transmission rate: hundreds to tens of Kbps. The lower the rate, the longer the transmission distance.
LoRaWAN core functions:
1, controlling wireless parameters: rate, power, frequency and ADR adaptive rate;
2. Realize QoS: reliable communication QoS:ACK, network management, etc.
3. Communication protocol: information redundancy, accurate reply (find the gateway with the strongest signal and send the reply information to the end node), wake-up node, etc.
4. Network security: node access, network layer and application layer encryption and decryption;
5. Node roaming: the mobile node switches from gateway A to gateway B;
6. Value-added services: node positioning, automatic node upgrade, etc.
The network entity of LoRaWAN is divided into four parts: terminal node, gateway, LoRaWAN server and user server.
1, end node: end nodes are generally various sensors, which are used for data acquisition, switch control, etc.
2. Gateway: LoRa gateway, which encapsulates and forwards the collected node data.
3.NetworkServer: mainly responsible for the integrity check of uplink and downlink packets.
4.ApplicationServer: mainly responsible for network activation of OTAA devices and encryption and decryption of application data.
5.CustomerServer: receives data from the node from AS, performs business logic processing, and sends the data to the node through the API interface provided by AS.
Laura
LoRa is a physical layer or wireless modulation used to establish long-distance communication links. Many traditional wireless systems use frequency shift keying (FSK) modulation as the physical layer because it is a very effective modulation to achieve low power consumption. LoRa is based on LFM spread spectrum modulation, which maintains the same low power consumption characteristics as FSK modulation, but obviously increases the communication distance.
Linear spread spectrum has been applied in military and space communication fields for decades. Because it can realize long-distance communication and anti-interference ability, LoRa is the first low-cost implementation for commercial use.