NB-IoT connected smart meters to improve gas metering in Shenzhen

Shenzhen Gas has a large fleet of existing gas meters, which are installed in a variety of hard to reach locations, such as indoors and underground, meaning that existing communications networks have struggled to maintain connectivity with all meters. The meter success rate is low, data transmissions are so far unstable and power consumption is too high. Against this background, Shenzhen Gas, China Telecom, Huawei, and Goldcard have jointly trialed NB-IoT gas meters to try and solve some of the challenges that the industry faces with today’s smart gas meters.

In March 2017, a number of smart gas meters manufactured by Goldcard were deployed in partnership with Shenzhen Gas, China Telecom and Huawei for trial of NB-IoT communications in a range of different scenarios and locations using 800MHz spectrum.

By using NB-IoT, Shenzhen Gas, China Telecom, Goldcard, and Huawei are able to take advantage of standardized data gathering and IoT platforms, where the whole end-to-end management of network operations can be conducted centrally by either the gas company or mobile operator. As part of the trial, the partners have implemented a new framework for smart gas metering, which allows new applications to be rolled out on the network quickly. This is hosted on the eCloud jointly developed by China Telecom and Huawei, with a data structure specifically formulated for the Chinese gas industry. This means that gas suppliers and their partners across China can take advantage of these new technologies.

The partners wanted to test the successful completion of a number of different scenarios, including pre-paid and postpaid billing and payments, valve controls, various meter parameter changes, different communications configurations and data integrity protection. As such, the trial has been designed to test a number of different scenarios and ensure that gas meters can be connected even in difficult to reach locations, such as inside metal meter cabinets or inside large buildings.

The targets the NB-IoT enabled gas meters were to be measured against were designed to be stringent and inline with the expectations of the gas industry performance requirements. These included a meter reading success rate of over 99%, ability to conduct meter readings on demand and successful reads even when the signal received by the meter is very weak.

• Improved efficiency – NB-IoT can reduce costs of operations for Shenzhen Gas by allowing real-time data analysis and prompt troubleshooting, which decreases the operational costs and improves operations efficiency.

• Data security – End-to-end security management of the NBIoT gas solution ensures data integrity. NB-IoT is only used by mobile network operators on licensed spectrum. This means that risk of interference is minimized and data security can be assured. As NB-IoT networks are based on existing mobile technology, they are easily deployed by mobile operators, and the enhanced coverage these networks offer ensures that all meters can be connected, removing the need to use multiple network types to obtain data.

• Improved power consumption – NB-IoT devices running on battery power can last up to 10 years. This is due to optimized communications profiles and low-power signal requirements. This means that meter maintenance costs can be minimized, as there is no need to visit meters and update components on a regular basis. Gas meters are also free to be located in any location along a pipeline; there is no need to locate gas meters close to power supplies or in specific areas to ensure network coverage. This gives the gas supplier a great deal of flexibility in how they roll out their gas smart meters, and the rollout programme can be optimized to ensure the lowest cost installation.

• NB-IoT has significant coverage advantages over other networks (up to 20dB over GPRS networks).

• The coverage delivered in field tests was good with an average uplink rate of 13 kbps and an average downlink rate of 7.8 kbps, which is sufficient for meter reading.

•  A trial was designed to simulate communications to 3 million meters within a 200 minute window. Various commands were simulated, including registration, meter readings, payments and valve control. The results of this trial were also very positive, with NB-IoT demonstrating that the average response time is 640ms, with data collected from every device within 60 seconds of first communication, averaging 30 seconds across all 3 million meters. NB-IoT proved that it is suitable for use in smart gas meters, even at this large scale, and is clearly a good option for connecting large fleets of smart gas meters in the future.