But while these initiatives reduce CO2 emissions, lower the municipal electricity bill and allow for needs-based lighting, experts are already eyeing up the opportunities that networked lamps present when configured as nodes in a multifunctional communication network.
Street lighting has changed dramatically over the centuries. From fire torches to oil lamps, and gas lighting to the modern light sources we take for granted on our streets today. But as we venture deeper into the information age, the next generation of street lighting may be just around the corner, and the buzzword is ‘connected’. Expect a revolution; engineers are already on the case and are looking at the new opportunities that arise from a connected street lighting infrastructure.
Conventional street lighting accounts for roughly 20 percent of urban electricity costs. It is also mainly responsible for unwanted light pollution. Excessive lighting not only squanders energy, it negatively affects the environment. Intelligent lighting, on the other hand, manages these excesses by illuminating areas of the city on a demand basis. Governments have already responded by issuing guidelines for more economical lighting systems in the wake of Regulation EC245/2009, which wants to see 100 million street lamps within the EU replaced by 2015.
How lamps become intelligent
Most networked street lighting installations involve new lamp hardware, gateways and cloud-based management software. Lamps can be retrofitted with the necessary hardware device (mounted in a small external enclosure, for example), though when switching from older bulbs to more efficient HID or HB LEDs, it is better that they be integrated directly by the lamp manufacturer. The upgraded lamps can then communicate with one another.
In Germany, Deutsche Telekom’s Street Lighting Management system configures street lighting as the nodes of an ‘IPv6 over Low power Wireless Personal Area Network’ (6LoWPAN). This is an IP-based wireless technology for energy-efficient short-haul networks - particularly sensor networks, where techniques such as header compression keep the data transmission low. Ideally, IPv6 and UDP headers can be compressed from 40 bytes and eight bytes down to seven bytes.
Mesh network construction
While the nodes handle the data transport of local traffic, gateways bridge the long-distance routes. Gateways receive information from the network nodes and pass it on to the municipal server infrastructure via mobile phone. At the same time, they send control commands to the nodes, such as ‘on/off’ of ‘dim’ instructions. Gateways can be attached to lampposts or placed in power distribution boards, and are usually positioned so as to reach the greatest possible number of nodes. One gateway can support up to 200 nodes, for example.
In order to avoid failures, a mesh network is employed as the network topology, ensuring each node is connected to one or more other nodes. As a rule, mesh networks are self-healing and are therefore very reliable and robust. As soon as a node malfunctions, the network automatically redirects the data across other nodes. Should a node lie beyond the reach of a gateway, other nodes in the vicinity will automatically act as repeaters and thus ensure that it is connected. All control commands are also stored locally in the node. And in the event of a gateway failure, the lamps will operate according to their most recent programming.
Programmable light
A web portal enables control of connected street lights over a very wide area, as well as at-a-glance monitoring of the network. Where once local authorities were previously dependent upon nocturnal inspection rounds or damage reports from citizens, a web portal automatically identifies defective lamps and provides an appropriate alert. Moreover, it can be used to determine the remaining life of individual bulbs so that replacement can be undertaken in a timely manner.
Intelligent lamps can be programmed to respond to real time needs. For example, using ambient light intensity sensors and motion detectors, lamps can be dimmed as daylight breaks or switched off altogether when the presence of people and/or vehicles has not been detected. Once the lamp’s motion sensor detects a passer-by, it can switch on or shine brighter, as necessary.
Street lighting is not the only sector of urban infrastructure that can be said to be in transition. Authorities, legislative institutions and companies worldwide are busily promoting the widespread digitisation of urban centres and communities; ‘Smart City’ is on the ‘digital agenda’ for Europe. Between 2014 and 2020, Horizon 2020, the European Commission’s research and innovation programme, will be awarding around 80 billion euros in funding for related projects, while the UK Research Councils are prepared to support Smart City research projects within these shores to the tune of £95 million.
The market is particularly buoyant. Machina Research predicts an increase in machine-to-machine (M2M) connections for the ‘Smart City & Public Transport’ segment from 72 million nodes counted at the end of 2012, to a staggering 747 million by 2020. Correspondingly, market turnover is forecast to climb from £4.9 billion to £17.05 billion.
Services range from sensor-based parking guidance apps that offer real time advice to drivers seeking available parking bays, to networked dustbins that convey their capacity levels to the rubbish collection service. To date, however, more comprehensive approaches that combine these individual schemes are in short supply. And that’s where intelligent urban lighting may have a timely role to play in the roll out of a citywide, multi-functional network.
A network for all?
Street lamps are ubiquitous and the pillars upon which they are mounted – the lamp posts – could form the backbone of an application-impartial, multifunctional, city-wide network infrastructure.
The European Innovation Partnership on Smart Cities and Communities (EIP-SCC) has not been slow in recognising the opportunities. In its Operational Implementation Plan, the EIP-SCC suggests that the ‘humble lamp post’ could host any number of Smart City applications - from air quality monitoring, smart metering and wireless services, to charging stations for electric vehicles.
Lamp posts thus become nodes in a flexible, citywide network infrastructure. Narrow-band communication taking place over the nodes is suitable for sensor-based applications, while the broadband network of gateways also supports data-intensive applications such as video streams.
The decisive factor for the long-term success of the urban network, however, is an open architecture. There must be docking points for citizens, governments and businesses. This is the only way to integrate the growing number of individual schemes into a broader ecosystem of networked objects, places and people.
Jürgen Hase is with the German global telecommunications operator, Deutsche Telekom, leading its M2M Competence Centre