The wireless meter reading system offers numerous advantages, including easy installation, convenient payment options, and simple data queries. Previously, FSK modulation solutions did not meet expectations, as they struggled to provide both long-range communication and low power consumption to extend battery life. Now, HOPERF’s LoRa wireless technology effectively addresses these challenges. For example, in a 32-story building with 4 households per floor, a total of 128 water meters can be read; approximately 10 bytes of water usage data can be transmitted every 15 minutes, and any water meter valve can be controlled within 10 seconds (water supply will be cut off for non-payment, and service will resume upon payment).
Analyzing User Requirements:
· Distance: With a building height of 32 stories, obstacles such as walls and doors can cause signal attenuation.
· Power Consumption: Demands are stringent, as the water meters are battery-powered and must enter sleep mode during non-communication periods to conserve energy.
· Scale: The network consists of 128 terminals, forming a small-scale wireless network.
· Topology: Active data reporting + data distribution from the gateway upon wake-up.
This scenario exemplifies a typical "long-range, low-power, low-bandwidth, low-cost" wireless network, making HOPERF’s LoRa system an ideal choice.
TDMA Communication Technology
We utilize TDMA (Time Division Multiple Access) communication technology, ensuring that all terminals within the network communicate without collisions. This maximizes bandwidth usage, eliminates retransmission delays, enhances overall network QoS, and reduces overall power consumption.
The underlying principle is illustrated in the diagram below: N terminals divide a period into N slots. Each terminal communicates with the gateway during its allocated slot. Slot duration depends on the communication rate and the length of actively reported data.
Specific Configuration:
· Communication Rate: Low-rate communication with a high spreading factor to leverage LoRa's long-range capabilities.
· Frequency: 470 MHz, in a free frequency band.
· RF Transmission Power: 20 dBm.
· Number of Terminal Nodes: 128.
· Maximum Upload Size: 10 bytes per transmission.
· Slot Duration: 7000 ms.
· Secondary Reporting Interval: 900000 ms.
· Maximum Wake-Up Data Size: 2 bytes.
· Wake-Up Interval: 7000 ms.
The timing and intervals for wake-up are illustrated in the diagram below.
Overall System Architecture
