Communication networks are the foundation of any smart city. The technology they rely on to capture and transfer data efficiently differs from one case to the next, depending on the requirements that need to be met.
The backbone of every communication network in a Smart City is broadband. This is what enables citizens, institutions and companies to gain Internet access and exchange data with the Smart City cloud. Copper cables are the conventional choice for broadband infrastructures, but fibre-optic networks and even wireless networks are also available nowadays. Wireless and mobile phone networks alike have developed in leaps and bounds over recent years – as illustrated by a live demonstration by Deutsche Telekom and Huawei in early 2016. Using millimetre wave technology, this showed that achieving connection speeds of as much as 70 Gbps was possible during multi-user operation. Based on 5G, the demonstration used an advanced version of multi-beam forming technology that ensures high-performance broadband connections in buildings and densely populated areas. According to Dr Wen Tong, Head 5G Developer and Huawei Wireless CTO: “Millimetre-wave MU-MIMO technology has enabled us to achieve unprecedented speeds in mobile broadband access, akin to those found in fibre-optic networks.” Multi-beam forming technology generates steerable pencil-shaped beams between the antenna array and customers’ devices. These beams are able to transmit and receive on the same frequency, separated by their different beam signatures. The mmWave multi-user MIMO technology used to demonstrate the record-breaking speeds delivers exceptional connectivity rates of 20 Gbps to each user – around 60 times faster than the fastest mobile broadband connection available today. This would enable 100 GB of high-resolution video material to be downloaded in just 40 seconds.
The same infrastructure, different features
The most distinctive characteristic of the 5G era, however, is the ability to accommodate a whole host of different requirements efficiently and reliably in a single infrastructure by using virtual network segments. This type of operation harnesses virtualisation technology to run multiple virtual networks in parallel within a single infrastructure. Its basis is the principle of network slicing, which specifies which topology, protocols and network resources need to be used. One virtual network segment might ensure real-time communication, for instance, while another uses the same infrastructure to transmit significant quantities of data in record time. The network changes its properties like a chameleon. Claudia Nemat, Member of the Board of Management of Deutsche Telekom, says: “The aim of 5G goes beyond simply offering better performance. This new type of mobile communications is also set to accommodate customers’ requirements in a more personalised fashion – whether they are looking for high data rates, short latencies or low-energy high-volume applications.”
New alternative for sensor connections
Smartphones and notebook computers are not the devices responsible for the majority of signals in a Smart City, however – it is the millions of sensors in the Internet of Things (IoT) that are behind this. Most of these sensors only need to send tiny data volumes, a task for which the broadband network is vastly oversized. On the other hand, conventional communication methods such as WLAN, Bluetooth and LTE often fail to provide the necessary range or object penetration – or are too cost-intensive for many small-scale applications. For this reason, a new type of network technology – Low-Power Wide-Area (LPWA) – has developed in recent years with the aim of connecting sensors and, as a result, everyday objects within a city to a communication network. There are various systems behind the term, one of which is Narrowband IoT, a type of technology that uses existing networks in a licensed spectrum – such as the 5G network – and supports the majority of IoT devices. It is particularly designed for applications with low broadband requirements (from 100 bps to a few kbps), including intelligent parking systems, electricity meters and waste management systems. Additionally, this technology enables far better reception within buildings when compared to the GSM mobile communications standard, for instance. Its low energy consumption also ensures a battery life of as much as ten years.
Connecting without a mobile communications network
Other LPWA systems work entirely independently of the mobile communications networks, using the unlicensed wireless spectrum. LoRa and Sigfox, both hailing from France, and the start-up company Ingenu are undoubtedly the biggest names in this field.
Distributed by Semtech, the LoRa solution is specifically designed for transmitting low data rates while at the same time handling extensive distances of up to 20 kilometres. Other benefits it offers are its inexpensive hardware, end-to-end encryption and the long battery life of its wireless units – as much as ten years. The LoRa Alliance, an industry association, has also defined the LoRaWAN open standard, designed to ensure that all devices which use it can be operated in the LoRa wireless network. “With this technology, cities in particular stand to save on costs and acquire crucial information that they can use to optimise their infrastructure,” says Marcus Walena, founder of Digimondo. The start-up is currently at work in major German cities, developing a LoRa communications network for the Internet of Things. “This is a cost-effective method of data communication that will give cities the right tools to face the challenges of the future,” states Walena.
A similar system – but this time based on a different type of modulation technology – is Sigfox. Also focusing on straightforward, economical and energy-savvy two-way remote transfer for low data volumes, Sigfox already exists (or is in the process of being launched) in 20 countries and its network is currently used by more than seven million devices.
Pursuing a different path to other network concepts, the US company Ingenu has used RPMA (Random Phase Multiple Access) to develop technology that can achieve a range of up to 65 kilometres (in areas without obstructions). Under real-life conditions, it still enables more than 700 square kilometres of coverage per telecommunications tower. There are now already 38 private networks worldwide that are equipped with this technology.
Alongside these three LPWA providers, it is possible to find several other companies offering wireless systems for connecting objects to a Smart City communication network. As a result, there is the risk that cities will rely on fragmented solutions rather than using standardised systems for their IoT. A Machina Research white paper commissioned by mobile communications and research company InterDigital indicated that failing to standardise these solutions could result in Smart Cities incurring costs of as much as 341 billion dollars by 2025. As Jim Nolan, Executive Vice President IoT Solutions at InterDigital, explains: “The world of IoT is currently characterised by competing technologies and platforms, further complicated by numerous standards development organisations, and this fragmentation is causing a delay in the widespread adoption of IoT. We can’t hope to realise any Smart City ambitions until all stakeholders can agree on a common set of IoT standards.”