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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 “last

RF & Wireless “last 100 meters” in low power, low cost, small devices. However, there will still be use cases where 802.15.4 based technologies are used especially in areas where it is already established. In spite of its installed base in smart energy, home and building automation applications, connect- Blue envisions that 802.15.4 will face competition in Bluetooth low energy in these applications as well. WLAN will be used in devices where cost, low power is less important and as a wireless backbone combined with the other wireless technologies. Which Wireless Technologies should one choose? Gateways are a requirement when connecting small lowpower short range devices. Sometimes the gateways are fixed devices connected to a backbone network and sometimes they are embedded within other devices e.g. in an Internet router (ADSL or GSM/3G/4G routers or similar). A mobile device can also act as a gateway and there are several use cases where this use can be Figure 12 Traditional Bluetooth Low Energy Use Case applicable. For example, one use case is when the sensor / device is carried together with the phone e.g. a body-worn sensor. Another use case is where the smartphone becomes a temporary gateway when it approa- ches the sensor / device (e.g. an access control system where the phone is used to authenticate the access using an Internet services). Figure 12 shows a use case where the traditional Bluetooth low energy concept of characteristics and services are exposed from the sensors / devices. This use case will typically require knowledge on behalf of the gateway on what services the sensors expose. Typically, the gateway will expose this knowledge as an Internet accessible API or by pushing data read from the sensors to an Internet based service. Figure 13 shows Bluetooth low energy and 802.15.4 used as transport for IPv6 based communication “end-to-end”. In this use case, an IP-based application in the sensor / device is transparently connected to an Internet service. This case typically uses compression techniques such as 6LoWPAN and CoAP to enable an efficient use of the limited resources of a Bluetooth low energy or an 802.15.4 network. This use case may also enable “end-to-end” security although this will require more computing power in the sensor / device. Figure 14 shows the use of WLAN serving as an intermediate backbone connecting islands of sensors/devices. This makes use of the multi-radio capability of the short-range radio chips already available e.g. chipsets Figure 13 IPv6 „All-the-way“ and IoT 50 hf-praxis 9/2014

RF & Wireless supporting simultaneous use of Bluetooth low energy and WLAN to create miniature gateways. The gateways communicate via Bluetooth low energy down-stream and WLAN upstream. The WLAN up-stream link is connected to a WLAN router connected further upwards to Internet services. This scenario may be used to extend the range or the system size. Figure 15 shows the use of gateways to create a system with interconnecting multiple technologies. The gateways are used to perform the necessary translation to a common backbone (e.g. an IPv6 backbone). This use is especially interesting and easy to use when interconnecting technologies via IPv6 “all-theway” as described in Figure 13. Summary The following are the conclusions one can make from this paper: • There is huge potential for “last 100 meters” of “things”. The main part of future growth in wireless Internet connectivity indeed stems from this area. • Security and privacy, both for private enterprise level IoT use cases and public use cases are essential and need to be individually investigated for each specific use case. • Low power, short-range radio technologies like Bluetooth low energy, 802.15.4 are often a requirement to enable these use cases and various gateways are needed to connect all these low-power devices to the Internet. • Some of the gateways will be fixed devices connected to the Internet but for some use cases there is a need for smartphones or other portable devices to serve as mobile gateways. • There will be several shortrange low power radios used in parallel but Bluetooth low energy is a rising star that connectBlue believes will likely take a significant portion of this market. ◄ Figure 14 Use WLAN „Mini Gateways“ to Extend Coverage and System Size. Figure 15 Interconnecting Multiple Technologies Mats Andersson is the CTO of connectBlue. Mats Andersson has more than 10 years of experience in wireless and more than 30 years of experience in the field of industrial automation. This includes managing development of industrial automation products at Alfa Laval Automation and ABB About the Author Automation Products. connectBlue® is a leading provider of robust Industrial and Medical wireless solutions, designed and tested for the most demanding applications and environments. connectBlue has its head office in Sweden and local offices in Germany and USA. hf-praxis 9/2014 51

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