How to test wireless M2M IoT devices for network readiness

Machine-to-machine (M2M) communication is a significant and growing subset of the larger Internet of Things (IoT) movement, so you have to ask, “Is my network ready for machine-to-machine (M2M) devices?”

IoT can include vehicles and home appliances, M2M applications target field services, environmental monitoring, healthcare, traffic control, agriculture, fleet management, public utilities, security and oil and gas applications. The tricky part of an enterprise M2M deployment is deciding which connectivity protocol to use and then figuring out how to test to make sure the rollout goes smoothly.

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This guide describes the strengths and limitations of seven wireless technologies and provide a checklist of items that you should review during the testing phase of the project.

M2M Types

M2M devices utilize a broad range of technologies, some legacy and some new and evolving. The following chart shows some of the most popular technologies found in M2M devices.

Network World / IDG

Cellular

Cellular is the most pervasive technology used in M2M communication because of its ability to transfer high volumes of data at high speeds anyplace where cell coverage is available. The challenge with current 4G technology is that it may soon be unable to support some M2M communications due to lack of bandwidth efficiency. New 5G technology promises lower latency, faster speeds, better battery life for many devices and significantly improved network capacity.

 Here’s what you need to consider when testing an M2M rollout based on cellular technology:

1. Coverage: With cellular, coverage is the first order of business. While most providers offer reliable coverage in the most populous areas and along Interstate highways, for more remote locations, coverage can vary greatly between providers. Cellular providers have coverage maps that show where devices should work, but there is no substitute for field testing the actual devices.
2. Throughput: Data throughput is another important test parameter. Make sure your cellular devices and providers can handle your usage scenario by testing with live or sample data. And be sure to plan for future growth.
3. Portability: If portability is a requirement, confirm that devices operate correctly on more than one network.
4. Battery life: Test M2M devices to ensure adequate battery life despite what the manufacturer says it is. Reliable re-charging and external power solutions may be required for some installations.

Wi-Fi

Wi-Fi is available just about everywhere, so it is relatively easy to connect M2M devices to an existing Wi-Fi network. On the plus side, data throughput can reach 1 Gb+ over distances of up to 300 feet, but cost and power consumption may make Wi-Fi less than ideal for M2M. Here’s what you need to test before using Wi-Fi for M2M communication:

1. Signal strength: For Wi-Fi installations it is important to test access-point signal strength throughout the coverage area.
2. Load testing: This is necessary to determine if there is enough capacity to handle all traffic, especially at peak times.
3. Security: Make sure all connected devices meet the security requirements for your organization, including current authentication and encryption standards.
4. Monitoring: It is important to identify the types of traffic utilized on the Wi-Fi network, locate potential bottlenecks, look for attacks and ensure mission-critical devices have adequate bandwidth at all times.

Bluetooth

Bluetooth has a range of 800+ feet and power consumption is fairly low. Bluetooth is also fairly inexpensive, and it benefits from its ubiquity, especially in the personal device segment (smart devices, wearables etc.). Here’s what you need to test:

1. Compatibility: There are so many different specifications of Bluetooth that both forward and backward compatibility is an important aspect of Bluetooth device testing.
2. Performance: You will want to test range, discoverability as well as quality of transmission, whether Bluetooth is used for audio or data transmissions.
3. Security: With Bluetooth being so commonplace, many companies, like Visa, recommend running regular Bluetooth scans on corporate networks to ensure only authorized devices are connected. Bluetooth devices have been known to be used for skimming and data theft.

ZigBee

ZigBee devices are best suited for small data sets. The operational range is only about 300 feet, but by using mesh networking and intermediate devices, ZigBee can transfer data over longer distances. ZigBee uses 128-bit encryption for all transmissions. Here’s what to test for a ZigBee rollout:

1. Placement: With the relatively short range of ZigBee devices, proper placement is important. Again, testing the actual devices in the field will help determine the best configuration. Enclosures and antenna placement can reduce signal strength so these should be checked.
2. Power loss: Make sure the device reliably performs the task it is assigned to do and that it can recover in a power loss situation. Critical data should be stored in non-volatile memory to ensure retention after a power loss.

NFC

Near-Field Communication (NFC) has a range of less than four inches, which makes it suitable for contact-less mobile payments, electronic tickets, access control and public transportation. Low cost and low power consumption also make NFC attractive.

1. Accuracy: NFC utilizes peer-to-peer communication with either a passive or active device like in an access control or mobile payment system), or two active devices (data exchange such as Android Beam). You want to test field strength, frequency accuracy along with basic connectivity and functionality. Small variations in frequency can negatively impact the read range and rate, leading to a poor user experience.
2. Access control: To test for access control, you can use a uniform type of access card. In some situations, it might make sense to use what is known as a golden unit, which is a type of access or payment card known to be manufactured to certain specifications. This can then be used to test all readers in a given installation.
3. Device compatibility: For a mobile pay system where users bring their own devices (it is estimated that well over 75% of all NFC devices are smart phones), it’s important to test with the widest possible range of devices.

Z-Wave

has low latency, low power consumption and an operating range of up to 300 feet outdoors. With a data rate limited to about 100K bit/sec, it is suitable for automation tasks like thermostats, security systems, lighting control and other sensors.

1. Controller coverage: Since Z-Wave uses both controller and slave devices, ensuring that controllers can reach each of the slaves is critical. Networks can be bridged, but that may come at a cost in reduced performance.
2. Transfer rates: As with other lower rate technologies, you need to make sure the data transfer rates are adequate.
3. Interoperability: Since Z-Wave is a proprietary technology, it is important to test for interoperability with other devices and possible interference with cordless phone systems and other electronic devices. Interference with Wi-Fi and Bluetooth is not a concern with Z-Wave.

Sigfox

Sigfox utilizes an ultra-narrow band that can transmit small packets of data long distances (30+ miles). Sigfox is a proprietary technology that requires a subscription and currently coverage is available only in the larger metro areas in the US. While only small amounts of data can be transferred, Sigfox devices generally consume very little power, providing battery life of 10+ years. Sigfox offers compatibility with Wi-Fi, Bluetooth and GPS.

1. Coverage: With Sigfox, you first and foremost need to determine there is adequate coverage in the geographic area where the devices will be deployed.
2. Data rates: Make sure the data transfer capabilities of Sigfox will do the job, as Sigfox provides just about 12 bytes in each upload message and 8 bytes in each downlink message.

We don’t know what the future holds for M2M communication, but it expected that reduced hardware and data transfer costs, together with ease of integration with platform-based services, will lead to even wider adoption of M2M devices.