The NB‑IoT communication of an ultrasonic water meter is implemented based on the end‑to‑end cloud‑pipe‑end architecture. The entire process includes four key steps:
1. Terminal-side measurement and data collection
The ultrasonic water meter uses the time‑difference method (ToF) to measure flow: a pair of ultrasonic transducers transmit and receive signals alternately. The flow rate is calculated by measuring the time difference between upstream and downstream propagation. The MCU collects flow data, performs temperature compensation, and stores it locally.
2. NB‑IoT network access and data transmission
The built‑in NB‑IoT module (e.g., BC95, A7670) is woken up by the RTC timer. It initiates network access via AT commands, completes operator authentication, and establishes a connection. Data is packaged in a standard format (e.g., TLV/Binary) with device ID, timestamp, flow, and battery status, then transmitted using protocols like CoAP/MQTT.
3. Network layer forwarding and security
Data passes through the NB‑IoT base station → core network → IoT platform (e.g., OneNET). The transmission is secured by DTLS encryption and device identity authentication to prevent tampering and eavesdropping.
4. Platform-side application and two‑way control
The water utility platform parses and stores data, enabling remote reading, billing, leak detection, and valve control. The platform can issue commands (e.g., read parameters, open/close valve) to the meter, which executes them and returns results via the NB‑IoT network.
Key low‑power mechanisms:
PSM (Power Saving Mode): Enters deep sleep after transmission, with current as low as μA level.
eDRX: Extends discontinuous reception to balance latency and power consumption.
Typical daily uplink power consumption is ~18.7 mJ, enabling a battery life of 8–10 years.
Post time: Apr-21-2026