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vor 9 Jahren

9-2014

  • Text
  • Wireless
  • Technologies
  • Bild
  • Devices
  • Bluetooth
  • Anwendungen
  • Komponenten
  • Applications
  • Rohde
  • Frequency
  • Mikrowellentechnik
HF-Praxis 9/2014

RF & Wireless phone

RF & Wireless phone accessories have lowered the costs). • Range: We need the capability to cover an enough range or have some capabilities to extend the coverage (repeaters, routers, etc.) without having too big impacts on the system cost. • An International Standard that is NOT domain-specific: Domain-specific standards will still be widely used but we want to find and select basic wireless technologies that fit many verticals. Figure 7 Fixed AND Mobile Use Cases Figure 8 Short-range Technologies with Power Consumptions, Distances and Data Rates computing engine (microcontroller). • Power consumption: Many use cases require battery or some kind of energy harvesting technology as a power source. • Ease-of-use: It must be easy to associate a device to the network and to the Internet service. • Security: Security (authentication and encryption) must be adequately supported by the wireless technology and sometimes end-to-security (all the way from sensors to the Web services) is required. • Available ecosystem: Possibility to connect to smartphones, tablets, PCs, home gateways, etc. is important. This requirement also drives volumes and has an important impact on the cost (a good example is Classic Bluetooth where the large volumes of phones and Which Wireless Technologies should one choose? Figure 8 shows a graphic representation of the short range technologies that support the main part of the drivers and requirements listed above. This graph mainly shows technologies that are available in mobile devices such as smartphones, laptops, etc. The reason for only showing wireless technologies available in mobile devices is the above mentioned requirement on an available ecosystem. One exception to the rule is 802.15.4 that both fulfills the requirement on an internationally used standard and is widely used in early IoT use cases for example building automation and smart energy. The illustrated range is point-topoint and heavily depends on the individual devices’ radio design and shall thus be considered as an indication only. The same concept applies for power consumption since the actual power consumption is use case dependent. Our illustration indicates how well the different technologies support low power applications. As we are focusing on the “last 100 meters,” we will look more into the wireless technologies situated to the left of the red line. Figure 9 shows a table on how different wireless technologies fit specific verticals according to connectBlue. Infrared and NFC can be ruled out except for very specific use cases / 48 hf-praxis 9/2014

RF & Wireless Figure 9 Technologies and Verticals verticals. connectBlue believes that 802.15.4 based technologies will become a niche technology especially in those areas it already is established such as home and building automation and smart energy (see more on this in the conclusions section later). Let us compare the three selected technologies seen from the drivers (requirements) identified earlier: Conclusions that can be drawn from the figure 10 table include the following: • All three technologies have built-in link layer authentication and encryption which sometimes needs to be completed with end-to-end security from the sensor to the Web application. • Some IoT use cases may be fully behind an enterprise firewall (e.g. a use case inside a factory where the IoT Internet Service runs on a local server). There are also IoT systems operating on a widearea network but acting as local networks by the use VPN tunnels or similar security mechanisms. • Correctly used, Bluetooth low energy has the potential for less power consumption than 802.15.4 (less overhead). • The lack of native support for 802.15.4 in the for the ecosystem’s important mobile devices (smartphones, tablets, laptops, etc.) is a problem especially for mobile or temporarily mobile use cases. • The ecosystem with phones, tablets, laptops and phone accessories will drive down the cost for Bluetooth low energy. • 802.15.4 has a main advantage in its range since many 802.15.4 based technologies (e.g. ZigBee) support mesh whereby coverage can be extended by using routers. • Bluetooth low energy is very reliable with its support for Adaptive Frequency Hopping (AFH) and other features inherited from Classic Bluetooth. • WLAN, also commonly referred to as Wi-Fi, can be used in devices with less demands on low power consumption and as a wireless backbone in combination with other technologies (more on this later). The connectBlue conclusion is that Bluetooth low energy has a high potential in becoming an important technology for the Figure 10 Comparison of Wireless Technologies and their Usefulness in IoT Figure 11: IoT Architecture for Short-range Sensors / Devices hf-praxis 9/2014 49

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