Smart cities – transformed

Author : David Armour, Senior Product Manager at Semtech

04 October 2018

The influx into the world’s urban landscapes is accelerating adoption of technologies being used in smart cities to drive greater efficiency through reduced operating costs and improved quality of life for citizens. And as this piece explains, the numbers behind this use of smart technology are growing.

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In a recent meeting of the LoRa Alliance, for example, it was noted that over 50 million LoRa-based devices have already been shipped globally, to date. This reflects a compound annual growth rate (CAGR) for the technology of more than 100% – with the continued emergence of new use cases every day.

For engineers working on these projects, one of the most critical decisions is to base their design on a network which provides long data range, secure bi-directional communication and battery-life of years (rather than months). For many current projects, such as those outlined below, LoRa Wide Area Networks (LoRaWAN) technology is supporting the transformation from today’s cities into sleeker and more efficient smart cities.

These citizen-rich, efficient cities of the future demand sustainable infrastructure to deliver smart twists in many areas of city life. The smart coverage and communication will be based on sophisticated implementation of wireless technology and intelligent decision-making by smart technologies. This will mean that each city’s informed decision-making will demand streamlined collection and analysis of real-time data from thousands of connected devices.

In addition, over-the-air (OTA) updates will support the millions of devices which will be deployed, maintained and updated over time to ensure easy scalability. These devices  will be able to collect data for use in governance, energy, mobility, infrastructure, technology, healthcare, and the citizens’ experience – plus many other use cases developed by engineers and smart cities.

Scaling down waste-management costs

In the real world, adding smart, real-time decision-making to city waste management services can provide deliverable improvements in measurement. With millions of commuters every day, South Korea’s capital city of Seoul is a classic example of how LoRaWAN networking can be used to minimise the cost of waste collection. Smart air-pollution monitoring has demonstrated that the city has realised a 46% increase in the recycling of waste, while also achieving an 83% reduction in cost.

Seoul’s waste difficulties began with the vast number of commuters and travellers filling or overflowing the city’s public waste bins as they moved through the urban landscape.

Historically, Seoul would have no real-time data on the fill level of each bin around target areas. The city’s solution to the efficiency challenge was to install a smart waste bins data system: using a LoRaWAN system, this enabled the city to track the fill level of each bin and the efficiency of the overall waste collection operation (see Figure 1 – links to ActiveMag).

These benefits have resulted in a lower amount of litter and cleaner public areas for Seoul. It has also allowed this city to reduce the smart collection of waste to a frequency of 66%.

Sleek switching to solar power

In Carson City, Nevada, city leaders have found that the implementation of a smart energy switch between legacy and solar power has proved an innovative solution to their energy issues.

Credit: Shutterstock

The solar equipment used in Carson City provided some sound advantages, but was also exposed to wind and snow in the local climate. Driven by a desire to maximise smart city thinking, Carson installed a smart network to support efficient switching between the two technologies at night –  as well as during cloudy or inclement daytime conditions. The city has installed a long-range and reliable network that can deliver real-time measurement and decision-making.

Managing the infrastructure for the switch, between the legacy and solar technologies, was implemented on LoRaWAN. By implementing advanced technologies, this network was able to combine efficient virtualisation with easy access by managers and in-field operators to data and reports through mobile computers.

The result of this real-time, smart city decision-making delivered an overall boost in solar power output of up to 750,000 KWH. In addition, the network enabled the city to encourage more efficient use of their labour force.

Sharing smart energy reduction

Making customers more aware of their energy usage, and the associated environmental benefits, has been part of another LoRaWAN initiative: one which has enabled two French cities, Lyon and Grenoble, to deliver real reductions in heating costs. As two independent cities, they are around 70 miles apart; however, sharing this technology has been a viable and efficient approach to implementing shared smart city thinking.

The result of developing this initiative has measured a 16% reduction in heating costs, while also encouraging citizens to adopt greater energy awareness. This awareness includes the environmental benefits of reducing energy usage and understanding the need to defer the cost of installing additional energy-generation infrastructure.

Enabling consumers to monitor their power usage with a LoRaWAN-based Internet of Things (IoT) interface equips them with greater control over their energy consumption. Improved real-time knowledge and control has also enabled them to monitor and govern their costs – and to minimise the output of greenhouse gases.

To encourage citizen participation, the platform used by Lyon and Grenoble also has a separate system to provide citizens with financial rewards for reducing energy consumption.

Costs versus metrics

Metrics based around Semtech’s LoRa technology indicate that the objectives of both engineers and target smart city use cases can be supported. Several features simplify the decision for engineers to opt for LoRaWAN, rather than use other network protocols to control and support cost reduction in smart cities.

The LoRaWAN gateways typically act as packet forwarders and send packets to a network server that resides in the Cloud,  via a backhaul connection that may use Ethernet, Wi-Fi, 3G or 4G/LTE. The low cost of gateways, compared to cellular base stations, allows the capacity of a LoRaWAN network to be increased by adding additional gateways, making scalability easy and inexpensive. The result is that LoRaWANs combine the ability to cover a wide area (see Figure 2) with relatively low bandwidth – as well as extended battery life, low-cost hardware and high connection density.

Credit: Shutterstock

Take, for example, a star network based on LoRaWAN technology. This communicates data directly into a single gateway from internal or external sensors – attached at distances up to 20 kilometres away. Despite the distance, the network operates without the complex coverage analysis which would be necessary to support a mesh network in the same application.

Any smart city application will also want to maintain a strong hold on cost. In LoRaWAN applications, low operating costs are supported by battery-operated sensors, which can run for up to 20 years. It lso eliminates the sensor power-source wiring used in GSM, LTE or Wi-Fi networks.

With a receiver current of 4.5 mA, the latest Semtech SX126x family provides a 50% reduction compared to the previous generation, and a high power option of +22 dBm. This extends battery life of LoRa-based sensors by up to 30%, which dramatically reduces the frequency of battery replacement.

A choice of operating bands is also essential for extending flexibility to different applications. Some smart cities may choose to operate the LoRaWAN in the unlicensed ISM band. This delivers minimal or no spectrum costs, while operating via an external service delivers added flexibility for a low connection fee.

Operating with multiple and competing network service providers helps smart cities to drive down costs, or they can choose to deploy a municipal city-wide network to host different applications. This can allow the cost to be offset by leasing bandwidth to companies within the city.

The robust signalling provided by LoRa can penetrate through buildings to ensure coverage in dense smart city areas. This can mean that a city can use a single gateway to cover multiple buildings, which are situated at up to two kilometres away – and ensure a long reach compared to other wireless solutions.

In addition to simple and secure installation, smart cities will also have the confidence of integrated AES-128 encryption and the flexibility of a seamless and scalability network. Support from the LoRa ecosystem will provide multiple sources and providers for hardware, while the LoRa Alliance will certify sensors and other devices for interoperability.

Measuring the benefits

Developing the networks and systems to produce more efficient, citizen-rich smart cities will require some innovative thinking from engineers and city leaders alike. Currently, there are 14 categories of indicators which have been included by the International Standards Organisation: these can help to measure the metrics of networking initiatives.

The growing proliferation of smart city technology can enhance the experience and effectiveness within many areas. These can include street lighting, traffic light maintenance, predictive maintenance, traffic flow, parking management, and many more areas. The reliability, long-range and battery-saving nature of LoRaWAN means that this list is likely to continue to expand rapidly.

As the world moves into a more populous landscape, engineers and smart city leaders are going to have to look carefully at the different choices for smart sensing and control. It is only by making the right choices at the right time that efficient networking will be able to collect and analyse data from thousands of connected devices to deliver the technology and services smart cities require.


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