Wireless connectivity for IoT

Wireless architecture for IoT

Before evaluating the various connectivity options for your IoT project, it’s important to understand the functional architecture of IoT solutions. IoT solutions require secure, bidirectional communication between devices, which could number anywhere between two and several million. A back-end solution that provides functions such as management, monitoring, analysis, automation is also required. The architecture is quite different from the typical web system and involves several layers:

Sensors and devices
Application back-end
Presentation / analytics

While being able to crunch large amounts of data off-device brings huge benefits, the cloud isn’t always available or you may require quicker response times. This is where Edge computing can help. Put simply, the Edge is where the data is produced and initially aggregated – static gateways, sensors, computers, smartphones, etc.

Does every product need connectivity?

Simply adding connectivity to a typical consumer product is no shortcut to success. The point of connectivity is to provide added value benefits to the end user, the producer, or preferably both. That may be improved performance, the ability to perform a product update, better insights, diagnostic feedback or something different.

While connectivity could be added to every household appliance, it has to be done with the customer first and foremost in mind. If the connectivity functionality is thrown together quickly and/or is difficult or cumbersome to use, it could present a security issue.

In 2016, security researchers uncovered a huge botnet – a hacked network using computers remotely to send out spam – of over 100,000 devices. The botnet included the expected, such as routers, and the unexpected, including many smart televisions and at least one fridge.

The most obvious product genres that are bound for connectivity include anything portable that could be easily lost. Item tracking technology is relatively low cost and there is already a level of familiarity thanks to functionality like ‘Find my iPhone’ and an obvious instant consumer benefit.

Of course, even when there isn’t a direct benefit to the customer of getting connected, the business itself could see numerous benefits through the collection and analysis of big data.

How do you know how your customers are using your products? If a fault occurs, does your business know? Getting such reports can raise awareness of bugs, and enable the business to quickly correct mistakes, delivering better and safer products to the customer. You could hold focus groups, but connected products allow (with customer permission) the collection and analysis of aggregated data from much larger sample groups.

To go wireless or wired?

Cabled connections still have a vital part to play for big business. Not only are there obvious security benefits of being able to control physical access, wired high speed connections such as optical fibres can handle vast amounts of data over significant distances.

Connection speed isn’t just about bandwidth, latency is also a factor. Wireless connections such as Wi-Fi is subject to interference as there are many devices sharing a limited number of frequencies. Dropped packets, higher latency and lower speeds all impact the quality of the connection.

Having a physical backbone of connectivity gives a certain level of assuredness, so when communication is critical, wired can often prove to be the best choice.

Wireless infrastructure is almost always a hybrid of wired and wireless, which offers a completely different level of flexibility and access compared to wired-only. That level of flexibility comes at a much lower cost than wiring in Ethernet ports all over a factory.

Choosing the right wireless connectivity standard

There are many different connectivity options for an IoT solution. Many are used in combination because of the different features and benefits of each one. Take a look at your smartphone, which has cellular, Wi-Fi and Bluetooth all built in as standard.

Wi-Fi and cellular are popular choices for when a device needs to be connected directly to the Internet. Bluetooth Low Energy is a great choice for connecting devices to each other and to a gateway device such as a smartphone when low power consumption is required.

Read more: Are There Too Many Wireless Standards?

The correct choice for your circumstances will depend on many factors, including:

Power requirements (mains or battery?)
Read more: The Importance of Average Power Consumption to Battery Life
Bandwidth requirements (how much data?)
Frequency of data transfer (how often?)
Range requirements (how far away?)
Physical size limitations (how big?)
Cost limitations (how expensive?), critical infrastructure and logistics.

Network topologies

Devices in a network have to be connected in some logical manner. The layout and interconnections are known as the network topology or architecture. Network topologies include point-to-point, bus, star, ring, mesh, tree and hybrid. When describing topology, devices are referred to as 'nodes.’

The simplest to understand is point-to-point, which is simply a direct link between two devices. Bus topology uses one main cable as a backbone, to which all nodes are directly connected. Each IoT use-case may require a different kind of topology to meet its unique challenge.

In star topology, each device is connected to a central hub – usually a gateway – with point-to-point connections. It’s low-cost, easy to add new node, and robust because if one connection fails, the others remain intact.

Tree topology consists of a central coordinator node, several routers to extend range, and end devices. Each end device is only able to communicate with its parent router or coordinator.

Another popular topology for IoT is mesh, in which every node has a direct point-to-point connection with several other nodes. This ensures the network can handle a high volume of traffic, it can cope with several failures, and range is improved by relaying messages through nodes.

Range considerations for wireless connectivity

One of the key considerations when choosing a wireless connectivity solution is the required range of communication. NFC for example works only over very short distances, while Bluetooth 5 offers substantially longer range than was previously possible. Depending on the configuration, at low speeds the range may exceed 1,000m.

Network topologies can also be used to extend range. For example, a low power network can be used to relay a message through nodes in a mesh network, or Bluetooth long range could be used to relay that same message with a single point-to-point or star connection.

Security issues for wireless connectivity

IoT is fundamentally changing how the world sees data security and privacy. Every end point device or gateway device and connection that gathers, transmits, stores or processes sensitive data is a potential risk.

Solid security relies on solid fundamentals. During the design phase, security should be baked in to every level of the product, from the physical chip to the data transmission and end applications.

The management of encryption and authentication are the foundation of resilient security, but there is no need for you to reinvent the wheel. Some open source libraries perform encryption to a very high standard and are well suited even for the resource constraints of an IoT device.

A study by HP found that 70 percent of the most commonly used IoT devices contain security vulnerabilities, including: Insecure web/cloud interface
Insufficient authentication and encryption
Privacy issues
Insecure mobile interface
Insufficient security configurability
Poor physical security

A vulnerable part of a product’s lifetime is the commissioning phase, so this should ideally be a one-time activity to limit risk. Once commissioned, the security details should be stored in the device for future use, and the commissioning channel should be closed so that a hacker is unable to force a device to re-enter into the commissioning phase. Of course, the need for secure commissioning needs to be balanced with usability.

Keeping your connected product updated

Wireless connectivity has brought so many benefits to products, but for developers one of the most interesting is the ability to issue updates and fix bugs after the product is sold.

As devices became more complex – digital music players, GPS watches, and so on – it quickly became both necessary and desirable to update devices to fix bugs and enhance the product without the need for a costly recall.

The combination of moving firmware from ROM chips to flash memory and the increase in wireless connectivity has led to great benefits for manufacturers large and small.

New standards are constantly being developed and if you can reprogram your device to take advantage of these it can lead to improvements to issues such as battery life and performance. By releasing when your product is ‘good enough’, your product development cycle shortens.

Power consumption for connected products

Talking about power consumption can be like running into a minefield of misconception, prejudice and marketing buzzwords. Determining what all the statements involve in reality is not always an easy task.

Power consumption measured in watts is the appropriate term for low power applications. Often the current consumption measured in ampere is used instead, making it more cumbersome to compare solutions as, for example, battery voltages vary.

Read more: Power consumption explained

The costs of getting connected

Short range vs cellular. Cloud solution or writing your own app.

There is as much variation in the cost of wireless connectivity solutions as there are numbers of solutions. In deciding between different options, it’s best not to just look at the total cost of implementation, but also consider the total value provided both to the end user and your company.

Low cost items with a low value – novelty items or products that need to be replaced regularly – are unlikely to favour more than a very basic solution. But solutions that provide significant value to the end user can be priced higher, and can therefore justify a higher production cost. Such application areas include smart cities, critical infrastructure and logistics.

Getting started with wireless connectivity

One substantial issue likely to emerge with the continued growth of IoT and connected devices is a lack of suitably qualified and experienced hardware engineers. Unlike software, where it’s possible for people to teach themselves easily and cheaply with nothing but a computer and some free time, hardware development requires larger investments in terms of time and money.

One solution to the skills shortage is to set up a rapid prototyping process by taking advantage of products and services designed to fill gaps in hardware and software development.

If This Then That (IFTTT) is a simple web-based platform that hooks together various apps, web services and IoT devices. It knows how to work with technology such as Amazon Echo so, if you’re having trouble getting your product or app to work with Alexa directly, you can utilize IFTTT as a stop-gap measure.

On the hardware side of things, the Nordic Thingy:52 is an all-in-one solution for helping anyone get started on hardware projects.

Containing a variety of environmental sensors and outputs including sound and light, the device functions as a Swiss Army Knife for the world of IoT development. Using a Thingy:52 allows you to focus on developing apps and/or establish what hardware functionality your product needs before committing to more expensive development.

Also from Nordic Semiconductor, the nRF Cloud allows easy connectivity and configuration of Bluetooth IoT prototypes in the cloud, with no coding required.

Wireless Connectivity for IoT

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