JüRGEN HASE, vice president of the machine-to-machine competence center at Deutsche Telekom, projects that smart street lights will form the basis of municipal networks and enable services in parking control, waste management, and traffic flow.

The next generation of street lighting will be connected. Cities all over the world are already experimenting with intelligent lighting systems that can be controlled remotely. They lower municipal electricity costs, enable demand-driven lighting, and reduce CO₂ emissions. Current designs are even taking that a step further: Experts see networked lamps as nodes in multifunctional communications networks for the "smart city."

Up until now, turning night into day and illuminating the dark has been the main task of street lighting. In the future, however, street lamps will fulfill many more functions. They will notify the garbage collection service whenever neighborhood waste bins must be emptied, or register a change in traffic volume and feed that data into an intelligent transport system (ITS). Street lighting will no longer be an isolated sphere but part of a networked urban infrastructure.

The basis of this vision is the emerging Internet of Things (IoT) and the associated concept of the smart city. Every conceivable object and location will be connected: cars, cargo containers, street lights, and car parks — even wristwatches, eyeglasses, and pens. They will each measure various parameters in their environment and digitize everyday challenges such as finding a parking space. At the center of this change is machine-to-machine (M2M) communication, the automatic exchange of data between networked devices either with each other or with a control center.

The public sector already recognizes the opportunities inherent in a higher degree of cross-linking. Smart city solutions are regarded as key in reducing energy and maintenance costs, complying with the legal requirements of climate protection and providing better services to citizens. Intelligent street lighting plays a central role in this. In fact, in many cities, defective lamps account for roughly 20% of all citizen complaints, and intelligent systems can automate the repair process. In combination with LEDs, a programmable light management system reduces urban electricity costs up to 70%.

Driving the networked city

Intelligent lighting systems have already been on the market for a couple of years. However, they have hardly gained widespread roll-out in any city or town. It is through the repositioning of street lighting as the backbone of the networked city that the breakthrough could be imminent. Authorities, private sector companies, and supranational institutions such as the European Union (EU) are actively promoting the digitization of urban infrastructure.

The European Commission has launched the European Innovation Partnerships on Smart Cities and Communities (EIP SCC). Between 2014 and 2020, Horizon 2020, the research and innovation program, will make available roughly €80 million ($103.5 million) in funding. The humble lamppost is particularly significant in the EIP-SCC's Operational Implementation Plan as the bright starting point of the networked urban infrastructure. In addition to street lighting, an application-agnostic network can facilitate any desired application — whether it is air quality monitoring, smart metering, or traffic control.

More than artificial light

To understand how smart street lighting will evolve, it helps to look at other operational scenarios involving machine communication. In the industrial sector, for example, M2M is used for remote maintenance of machinery and equipment. Technicians can see the status of wearing parts and consumables from afar. As soon as an error occurs or the system detects a pre-defined pattern, it automatically alerts the staff. This creates a new level of transparency concerning production processes, overdue maintenance, and the use of resources. Intelligent lighting systems provide similar benefits. In order to identify defective lamps, the city will no longer be dependent upon nightly inspection trips and complaints from citizens. The system will reveal the status of the connected city lighting right at its hub.

When things around us become smart, their range of functions expands. In Boston, MA, for example, there are smart park benches where citizens may charge their smartphones and tablets. At the same time, these park benches also measure environmental factors such as air quality and noise levels. Thus, cross-linked benches provide more than seating accommodations. They mutate into charging stations and measuring instruments for sustainable urban spaces. Analogously, networked streetlights are more than mere appliances for artificial lighting. They become nodes in a multi-functional network.

Basic architecture of intelligent lighting

What requirements must an intelligent lighting solution meet in order to act as a multifunctional network? Its basic structure must correspond to the multiplicity of current market solutions. First, technicians equip the lamps with electronic devices by either placing the hardware in a small box attached to the outside of the street lamp or retrofitting the devices into the fixture. Alternatively, the lamp manufacturer will integrate the hardware directly. Of course, some of the older model lamps may need updating to more efficient LEDs. Once upgraded, the lamps can be integrated into a short-distance network.

In addition to the hardware in the lamps, mobile communication gateways are used for exchanging data over long distances. These can be attached to lampposts or housed in power distribution grids. Usually, they are positioned so that each gateway reaches a maximum number of nodes. In the Street Lighting Management solution of Deutsche Telekom (based on the PE.AMI system from Paradox Engineering), a single gateway supports up to 200 nodes. It receives information from the nodes and forwards it to a server infrastructure in the cloud or to a city's local server. Likewise, the gateway sends control commands back to the nodes and instructs them to switch the lights on and off or dim them.

Neural pathway of the smart city

The combination of nodes and gateways produces a double-layered network. The narrowband network of nodes is pre-destined for sensor-based applications such as smart metering. The broadband network of gateways is meant for data-intensive applications such as traffic monitoring with video cameras. Mesh networks form the network topology. Each node is thereby connected with one or more other nodes. As a rule, mesh networks are self-healing and thus highly reliable. Whenever a node fails, the network automatically forwards the data via other nodes.

Street lighting solutions can establish multi-purpose networks.

In regard to data transmission, IP standards will form the basis. Objects and locations have IP addresses assigned and are therefore clearly identifiable. The IPv6 Internet Protocol is regarded as the key prerequisite for the IoT and the smart city. Compared to the previous protocol, IPv4, it expands the address space from 2³² to 2¹²⁸ unique addresses and thus ensures that address space in the networked city will not run out. Particularly promising as well is the IPv6 over Low Power Wireless Personal Area Network protocol (6LoWPAN). As an energy-efficient, short-range radio technology, 6LoWPAN is especially ideal for sensor networks.

Operating system for the city

In addition to standards for data transmission, interoperable management systems software is essential. The majority of intelligent lighting solutions offer Web-based portals through which the associated lamps are programmed and managed. Here, cycles may be specified in which the lamps are switched on and off. Once combined with brightness and motion sensors, complex patterns are possible. As the sky darkens, the lights shine brighter. In seldom visited areas, the lamps will switch on only when their motion sensors detect people passing by.

In order to support more smart-city applications, management software for city lighting must not remain sealed off. It should be extensible by means of third-party applications. Ideally, the city will implement an application-independent management portal - a type of operating system for urban areas that will provide docking points for government agencies, citizens, and the private sector.

Cooperation requested

In addition to funding, inherent high complexity has so far been an obstacle in the way of a smart city solutions breakthrough. It requires the cooperation of different industries with different competencies, and this is especially true for intelligent lighting systems. In addition to traditional manufacturers of lamps and bulbs, hardware manufacturers, software providers, and connectivity service providers all come into play. Negotiating individual contracts with each of these players, however, can be very difficult for customers — particularly as the compatibility of the components being utilized must be ensured.

To facilitate this procedure, international mobile operators such as Deutsche Telekom will be able to step into this market by bundling all the necessary components into complete offers. The foundation for this is an extensive partner network covering all niches of the networked ecosystem. For instance, historic street lamps represent a typical challenge. In order to upgrade them, particular components as well as an in-depth knowledge of restoration are essential. The partner network includes smaller companies that have specialized in the restoration of historic street lamps as well as in all associated crafts. Challenges such as lamp restoration or even the integration of different IT systems can thus be collaboratively solved. Cooperation is the key to the networked city, and intelligent street lighting is a promising starting point.