Internet of Things Technology ReviewReference Material for Designers, Engineers & Specifiers.

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INTRODUCTION ................................................................................................................... 3

WIRELESS TECHNOLOGIES ................................................................................................ 4

IOT COMPARISON TABLE ................................................................................................... 9

CASE STUDIES .................................................................................................................... 10

WIRELESS TOPOLOGIES ................................................................................................... 12

Network ..................................................................................................................... 12

Frequencies ............................................................................................................... 14

CONCLUSION ...................................................................................................................... 11

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Introduction:Wireless communication and embedded micro-electromechanical sensing technologies have evolved at a rapid pace. Many of the devices we use every day can now connect to the Internet, and this has made wireless sensor networks possible. The desire to maximize energy efficiency and improve environmental conditions has led to the emergence of new products used to monitor, control, and share information in networked homes and buildings.

Enter the Internet of Things. The Internet of Things (IoT) is a description for embedded and network cloud technologies that enable remote monitoring and control of sensors and systems. IoT can be used in commercial, industrial, utility and residential applications. You’ll find the IoT’s remote monitoring and control applications in hospitals, parking lots, shipping departments, and even bathrooms.

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Wireless Technologies

One important task for IoT developers and system architects is determining which wireless technology best suits their applications’ needs. This can be a daunting project. Many competing wireless technologies appear to have overlapping features or be interchangeable. This paper maps out the pros and cons of several wireless protocols and identifies key items to consider when selecting a wireless technology for a given application.

ZIGBEE:

ZigBee is a short-range, low-power consumption communication link that allows for connections of up to 100 meters. ZigBee end nodes communicate on a local personal area network (PAN) and require an additional device, called a border router, to communicate to cloud services or smart phones. ZigBee operates over the IEEE 802.15.4 media access control network layer typically, in the 2.4GHz spectrum. IEEE 802.15.4 specifies the physical layer and data link layer protocols for LR-WPAN (low-rate wireless personal area networks), making it an ideal option for simple, inexpensive applications. Some ZigBee channels overlap with 2.4 GHz Wi-Fi channels.

Both Wi-Fi and ZigBee use frequency hopping and spread-spectrum techniques to avoid interference. ZigBee transmissions speeds typically top out at 250kbits / second. ZigBee is a low-power wireless technology and may be suitable for battery-powered applications. ZigBee end nodes can act as network repeaters in a network mesh topology to extend their range if needed.

For the 2.4 Ghz implementation with 18dBm transmit power, -6dBm antenna insertion loss and the transmitter placed at a height of 6m from ground, the range for ZigBee increases to 300 meters. This may vary depending on multiple factors such as the environmental, but assuming there are no environmental issues and current radios are being used, the range can be pushed up to 300m.

The Digi Xbee Pro 1W radio is a 802.15.4 radio using the same family of controllers as Mars’ current ZigBee radio, but implementing a power amplifier to give a line of sight of 1200m. It is worth mentioning that with the right front end, a custom ZigBee radio can go beyond the range of 300m.

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ZIGBEE PROS AND CONS LIST

PROS CONS

Low power, suitable for battery devices. Requires a separate border router device.

Utilizes an open specification IEEE 802.15.4 MAC layer.

Incompatibility between some device vendors who implement non-standard

network stacks.

Meshing: there is no single point of failure.

Network physical coverage is relatively higher

Suitable for many end nodes at one physi-cal location.

Wireless Technologies Continued

For 2.4 Ghz implementation with 18dBm transmit power, -6dBm antenna insertion loss and the transmitter placed at a height of 6m from ground, the range for ZigBee increases to 300 meters. This may vary depending on multiple factors such as the environment, but assuming there are no environmental issues and current radios are being used, the range can be pushed up to 300m.

The Digi Xbee Pro 1W radio is a 802.15.4 radio that uses the same family of controllers as Mars’ current ZigBee radio, but implements a power amplifier to give a line of sight of 1200m. It is worth mentioning that with the right front end, a custom ZigBee radio can go beyond the range of 300m.

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Wireless Technologies Continued

Z-Wave

Z-Wave is a proprietary low-power wireless communication protocol that is comparable to ZigBee. Z-Wave operates over the 900MHz spectrum, so interference issues may arise with some 900MHz cordless phones or wireless video devices. This wireless communication protocol requires an additional device, called a primary controller, to communicate to cloud services or smart phones. Z-Wave has transmission speeds typically in the 10kbits – 40kbits / second range. End nodes can be set up to act as network repeaters in a network mesh topology to extend their range.

Z-WAVE PROS AND CONS LIST

PROS CONS

Suitable for many end nodes at one physical location.

Proprietary communications limit customization and flexibility.

Ensures compatibility of all Z-Wave certified devices

Requires a separate primary controller device.

900MHz band may have better performance pass through walls.

A single Z-Wave network has a limit of 232 nodes. Several Z-Wave networks can be

bridged to increase overall size.

Meshing: there is no single point of failure.

Low power

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Wireless Technologies Continued

Wi-Fi:

Arguably the most popular form of wireless networking, Wi-Fi is a medium-to-high power technology that uses radio waves in order to provide wireless high-speed Internet and network connections. Wi-Fi IoT devices typically operate over the 2.4GHz spectrum. 5.8GHz Wi-Fi, while common on computers, is uncommon on IoT devices at the time of this writing. Wi-Fi end nodes most often communicate in infrastructure mode where they communicate to cloud services or smart phones through a Wi-Fi router that is likely already present in most homes. Wi-Fi offers the fastest connection speeds, for IoT devices, typically into the 10Mb / second range.

WI-FI PROS AND CONS LIST

PROS CONS

Suitable for tens of end nodes at one physical location.

Relatively higher power consumption needed

Relatively faster connection speeds 2.4 GHz band may be congested

End-user familiarity

Separate router not required

It is worth noting that things could change later this year if 802.11ah arrives on the market with the promised features.

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BTLE PROS AND CONS LIST

PROS CONS

Low power consumption Network supports few end nodes

Easiest hardware design option 2.4 GHz band may be congested

Wireless Technologies Continued

Bluetooth Low Energy (BTLE):

Bluetooth low energy is a low-power lightweight subcategory of Bluetooth. As the name suggests, the primary difference between Bluetooth and Bluetooth low energy is power consumption. BTLE operates over the 2.4GHz spectrum. Some BTLE channels overlap with ZigBee and Wi-Fi channels. BTLE end nodes most often communicate in a point-to-point link, for example from a device to a smart phone. Recent advances in Bluetooth allow BTLE end nodes to work as network repeaters in a small mesh network to extend their range. BTLE devices operate in a network star topology, with BTLE networks requiring an additional router to communicate with cloud services, though they can communicate directly with smart devices such as phones or tablets. If you need to design something that can easily communicate with any modern mobile platform, particularly Apple devices, BTLE will most likely be your best option. In addition, this type of wireless protocol is ideal for devices that run on batteries for extended periods. BTLE has transmission speeds between 250kbits – 1Mbits / second.

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IoT Comparison Table

IOT PROTOCOL

FREQUENCY SPECTRUM

MAXIMUMTRANSMIT

POWER

MAXIMUM DATA RATE

MAXIMUM RANGE

NETWORK TYPE

USE CASE POSSIBILITIES

IN IOT APPLICATIONS

ZigBee

2.405 – 2.480MHzUp to 16

Channels

Typically 100 mW 250 kbps 10 - 100 m

Mesh or point to

point

Remote monitoring and

control of battery powered wireless sensors / controls. Smart remote for

TVs.

Z-Wave

908.42 MHzUp to 3

Channels

Typically 1 mW

9.6 / 40 / 100

kbps 10 - 30 m Mesh

Home automation remote monitoring

and control. Wireless control

for power outlets, light switches.

Wi-Fi

802.11g

802.11n

2.4 – 2.485GHz Up to 14

Channels

5.15 – 5.85GHz12 to 25

Channels

Typically 1 W 1 Mbps to

300 Mbps 100 m Star

High data rate or real-time monitoring and control

applications. Voice activated products.

Blue ToothLow Energy

(BTLE)

2.402 – 2.480MHz Up to 39

Channels

Typically 100 mW 250 kbps 10 - 100 m

Star,Scatternet, or Point to

point

Local user interface for appliances /

devices.

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Case Studies

Somfy Z-Wave to ILT Interface:

IoT has become a key component of home automation and smart homes because it adds beyond-line-of-sight monitoring and control. Within and around a building, home automation applications often include short to mid-range end nodes (remote sensors and controls). Mars client Somfy Systems of Dayton, New Jersey needed a digital motor interface to control window coverings for residential areas. This digital motor interface needed to be capable of producing real-time status reports for motorized blinds and shades. Range was not a factor because of the application. The Z-Wave Digital Motor Interface (ZDMI) is a Z-Wave routing device that resides as a node within a designated Z-Wave control network. By utilizing wireless Z-Wave, an inter-operable two-way RF mesh networking technology, the ZDMI receives control commands from a central controller and sends back motor position status.

Kimberly-Clark Intelligent Restroom

Mars client Kimberly-Clark of Atlanta, Georgia was looking into creating an “intelligent” restroom that would have the ability to monitor battery life and low paper in their paper towel dispensers. The goal was to reduce the amount of supplies and maintenance required to support an office restroom. Again, because of the application, range was not a huge factor. Initially, Wi-Fi seemed like the better option because of its high data rate and real-time monitoring capabilities. However, Mars ended up utilizing the ZigBee protocol because of its compatibility with battery-powered wireless sensors.

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Wireless Topologies

Network

There are a few major network topologies commonly used in wireless technology today:

Star Network: A star network is the most common computer network topology. In a star

network, there is a central hub, which can also be known as a router, gateway, or controller,

depending on the technology. All the nodes communicate directly with the hub, and then the

hub relays messages to the Internet or to another hub. If nodes want to communicate directly

with each other, the message is relayed via the hub. The transmission lines that are formed

between a hub and the nodes form a star-like arrangement. This is typically how Wi-Fi and your

cell phones work.

Typical Star Network Topology

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Mesh Network: In a fully-meshed network, there is no need for a central hub. Any node can act as a relay to any other node. The idea being, if two nodes cannot reach each other directly, the message can be delivered through one or more other nodes in the mesh. Mesh networks can reach greater lengths than other technologies by hopping a message through several nodes. There are many variations to a meshed network. Some nodes may opt not to route messages. A battery powered device may do this to conserve power. Another variation may direct some messages to a single gateway node. The gateway would bridge messages on the mesh network to another network, such as the Internet, using a different communication technology, such as ethernet or cellular.

Typical Mesh Network Topology

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Point-to-Point Network: In a point-to-point network, two devices are paired and connected with each other. Ultimately this tends to look like a star network, as it is usually a less capable device (like a headset) connecting to a smartphone or computer, which acts like the hub.

Frequencies

With so many wireless devices, it can be helpful to select frequencies that are less popular to avoid jamming and interference. However, there are also advantages to using higher or lower frequencies. Lower frequencies typically have longer range and are less affected by buildings or metal along the transmission path. Higher frequencies allow for increased data rates but are not as good at penetrating metals.

Typical Point-to-Point Network Topology

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While there are similarities between many of the IoT wireless protocols, selecting the appropriate technology is critical for project success. The most important thing a designer, engineer or specifier can do is to thoroughly define and prioritize exactly what it is that the IoT system needs to accomplish. Home and building automation systems and products may be single-focused or may integrate and coordinate several functions such as security, safety, entertainment, comfort, energy management, communication, and appliance control.

These products are capable of processing and exchanging information, and include flexible and adaptable designs that support sophisticated sensors and controls for various applications including lighting and energy management, garage door openers, HVACR systems, security, and appliances. From intelligent lighting controls, to safety sensing and monitoring devices, to central digital building controllers, Mars International has experience with the technologies, platforms, and protocols required to design and build complete product solutions.

Conclusion

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