Application of LoRa communication meter in intelligent building energy consumption management and monitoring

1. Introduction to LoRa technology

LoRa, the full name of Long Range, is one of the low-power wide area network (LPWAN, Low Power Wide Area Network) communication technologies. It uses advanced spread spectrum modulation technology and codec scheme to increase the link budget and better Anti-interference performance. LoRa's link budget of up to 157 dB enables the communication distance to reach more than 15 km (depending on the environment). It not only maintains the same low power consumption characteristics as FSK modulation, but also significantly increases the communication distance, while improving network efficiency and Interference is eliminated, that is, terminals with different spreading sequences will not interfere with each other even if they use the same frequency to transmit at the same time, and have better stability against communication deep fading and Doppler frequency shift.

Currently, LoRa mainly operates in free frequency bands around the world, including 433, 868,

915 MHz etc. This article uses the LoRa module in the 433 MHz frequency band, with a channel spacing of 2MHz, half-duplex, and transparent encrypted transmission to ensure data transmission security. It has the characteristics of long distance, low power consumption, multi-node, and low cost, and is suitable for building equipment that is widely distributed and widely separated. Communication network with long distance, anti-interference ability and low power consumption. This frequency band belongs to the ISM license-free frequency band, and there is no need to pay fees to the operator. There is less interference in this frequency band, and LoRa can well support communications in this frequency band.

2. Intelligent building data transmission network design based on LoRa

The building has a large area on a single floor, a complex structure of each functional zone, a large number of room partitions, and diversified energy consumption types. If the traditional integrated wiring method is used, there will be problems such as huge construction volume, high fiber cost for wiring equipment, long time span, and difficulty in subsequent maintenance and replacement. Moreover, the construction of intelligent building energy consumption management system is a late-stage reform.

Due to the influence of the location of the cable wells in the early stages of building construction, it is likely that a large area of repeated wiring will be required. This in itself is a waste of energy. It will also hinder the normal operation of the hospital during renovation and is extremely inefficient. Therefore, taking into account the actual situation of the hospital that has been put into operation, wireless data transmission was chosen to speed up the construction process to the greatest extent, save resources, and at the same time minimize the impact on operations.

According to the characteristics of the intelligent energy consumption management system and the actual situation of the building, the system is divided into four layers: on-site collection equipment, gateway, terminal data processing equipment, and cloud. The use of LoRa technology for wireless data transmission eliminates the cost of integrated wiring cables, reduces the difficulty of construction, greatly shortens the construction time and simplifies the later maintenance process, making it easier to carry out maintenance on each node equipment. Perform repair and replacement.

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