Data integrity with the Internet of Things

also ISM spectrum available in sub-1GHz bands, all of which are commonly used for IoT applications. The band is centred at 868MHz in Europe and 915MHz in the US. A challenge arises when multiple devices located in close proximity are sharing the same ISM band. Transmitting devices can interfere with nearby receiving devices, such as in hospitals, where there are a wide variety of machines sharing the same ISM band. The ability of a radio to operate in the presence of such interferers is measured by the blocking specification. The challenge extends beyond devices operating within the ISM band. Without sufficient blocking capability, mobile phones or tablets operating nearby could cause a loss of communication in the system.

By Michael Dalton, Product Marketing Manager in the IoT Group at Analog Devices


iven the explosive growth in the number of devices in the Internet of

Things (IoT), creating reliable wireless connectivity among them is proving a great challenge. Existing wireless connectivity technologies for consumer devices do not always satisfy the performance demands of industrial and healthcare systems, which have different priorities for safety, accuracy, time sensitivity and reliability. Cellular systems are often unsuitable in terms of battery, cost and data throughput. Extremely reliable systems exist today for niche industrial and military applications, but they are designed with reliability being top priority, not cost, whereas industrial IoT needs both.

SMART ‘PLACES’ A key attraction of connected devices in manufacturing includes the potential for yield improvements. To achieve this, it is often necessary to gain remote control of various devices in the production chain to implement adjustments. An example is a control valve for a boiler operating in a chemical production process. Immediate, autonomous control of this valve can make real-time adjustments, based on feedback from other stages in the process, leading to more optimised overall efficiency. In the medical world, hospitals and care centres require wireless connectivity


to monitor patient vital signs to replace clunky wired solutions, ideally with sensor patches connected through a local gateway.

And in smart city applications, with advanced image and acoustic sensing and processing methods, systems mounted in public spaces, such as lampposts, can detect vehicle accidents or criminal activity with a high degree of confidence. This information can be relayed via wireless communications to the appropriate agency or unit, along with the location information to enable faster emergency response.


Each of these examples are subject to distinct environmental challenges that can negatively impact wireless communication. The steel construction and thick walls of factories create large obstacles that can degrade the power of an RF signal to the point where it can’t be received by the target device. The receiver sensitivity of the radio used in the target device will determine how much signal degradation can be tolerated. As little as 2dB change in sensitivity could be the difference between successful and unsuccessful reception. Connected devices will typically operate in the relevant ISM band for that region; ISM bands are license-free. 2.4GHz is standardised globally, and is widely used by Wi-Fi and Bluetooth devices. There is

In smart city applications, with advanced image and acoustic sensing and processing methods, systems mounted in public spaces, such as lampposts, can detect vehicle accidents or criminal activity with a high degree of confidence

EFFECTS Radio transceivers are built on processes that are prone to variations in performance, depending on the operating environment. These are temperature changes, voltage supply reductions as batteries discharge, and silicon manufacturing variations across devices, all of which can cause changes in the operating stability of the device. Let’s assume an event sensing emergency response system operating on a street light: cold winter temperatures could cause the output power of a device to vary or the receiver sensitivity to degrade, resulting in loss of communication. Consumers can tolerate such problems, but it would be unacceptable for an emergency response system. System designers must ensure that the components selected for the sensing and communication system are robust over variable environmental conditions. Reliability is also a concern of the communications microcontroller. Although extremely reliable, both flash and non-volatile memory can become corrupted as a result of unintended effects caused by the operating environment, or even through malicious hardware hacking. Regardless of the mechanism, it is imperative that microcontrollers are equipped with the necessary integrity features to identify when a device has been corrupted. Once identified, it can either correct the error or shut the device down, ringfencing the wider system’s security. Technologies developed by Analog Devices cover every stage of the IoT signal chain, from sensing and measuring, to interpreting and connecting the data. Ensuring the quality and integrity of the information created through this chain is a core design principle and a fundamental requirement to fulfill the true potential of the IoT.

Analog Devices


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