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HOW TO CHOOSE CONNECTIVITY MODEL FOR IOT

Overview of IoT

Internet of Things is the concept where in all physical devices can be allocated unique identity number and connected to internet for automatic bidirectional data transfer to cloud for storage, analysis and decision making by intelligent software, then to user through user interface for monitoring and control. Hence IoT serves as the core for digitization and automation of home, industry and power grid. The main components of IoT are sensors/devices/actuators, connectivity, data processing and user interface.



Need of smart sensors

The sensors are used to collect data of all required parameters from a machine or industry. Sometimes a device with many sensors embedded in it and cameras can also be used to gather data. The actuators are used to incorporate the orders received from user interface or intelligent decision making algorithm. The data collected from the sensors are pre-processed at the sensor nodes using inbuilt processors to avoid transfer of large volume of data to cloud (for limiting bandwidth) and unnecessary delay in decision making for conditions which require emergency attention (for minimizing latency). This approach is called edge computing or fog computing. The data can be stored in memory at the sensor node for short span. The data will be sent to cloud only based on requirement to minimize band width requirement.

Selection of connectivity

The data gathered by sensors should be sent to cloud through different type of connectivity. If we want to transfer huge volume of data the bandwidth required is more. If the transmission range is more, then power consumption of sensors will be high which leads to quick draining of sensor battery. Type of connectivity to be selected based on bandwidth, range and power consumption. Possible modes of connectivity are

(i) Satellite where communication network is established through satellite directly. This is used for long distance data transmission and sensors are not under coverage of cellular tower. This will have high power consumption, high range and high band width. Iridium is a commercial satellite constellation capable of delivering true global coverage, uniquely qualified to provide global satellite IoT services due to its network architecture of 66 Low Earth Orbit (LEO) satellites, blanketing the earth with reliable and ubiquitous coverage.

(ii) Cellular where physical objects are connected to the Internet utilizing the same cellular network currently used by smart phones. In other words, this technology can connect IoT devices using existing mobile networks. Thus, it eliminates the need to invest and develop a separate dedicated network infrastructure just for IoT devices. This will have high power consumption, high range and high band width.

(iii) Ethernet where communication takes place through a hard-wired connection, so the range is short because it’s only as far as the wire length. It will have low power consumption and high bandwidth. Data from sensors are sent to cloud through gateway. Gateways act as bridges between sensors/devices and the cloud. Many sensors/devices will communicate to a gateway and the gateway will then take all that information and communicate to the cloud. Gateway can communicate with sensors operating with different protocols likeLPWAN, Wi-Fi, Bluetooth, and Zigbee, among many others. Gateway communicates to cloud using standard MQTT protocol. Gateways can pre-process and filter the data being generated by sensors/devices to decrease transmission, processing, and storage requirements.

(iv) Wi-Fi (Wireless Fidelity) is the most popular IoT communication protocols for wireless local area network (WLAN) that utilizes the IEEE 802.11 standard through 2.4 GHz UHF and 5 GHz ISM frequencies. Wi-Fi provides internet access to devices that are within the range of about 20 - 40 meters from the source. It has a data rate up to 600 Mbps maximum, depending on channel frequency used and the number of antennas. In embedded systems, ESP series controllers from Espressif are popular for building IoT based applications. ESP32 and ESP8266 are the most commonly use Wi-Fi modules for embedded applications. This will have low power consumption, low range and high bandwidth compared to cellular and satellite.

(v) Bluetooth is a technology used for exchanging data wirelessly over short distances and preferred over various IoT network protocols. It uses short-wavelength UHF radio waves of frequency ranging from 2.4 to 2.485 GHz in the ISM band. Here the data is split in packets before sending and then is shared using any one of the designated 79 channels operating at 1 MHz of bandwidth. The range of Bluetooth technology is between 50 – 150 meters and the data is being shared at a maximum data rate of 1 Mbps. Bluetooth also has a module Bluetooth HC-05 that can be interfaced with development boards like Arduino or Raspberry Pi.

(vi) ZigBee is another IoT wireless protocols has features similar to the Bluetooth technology. But it follows the IEEE 802.15.4 standard and is a high-level communication protocol. It has some advantages similar to Bluetooth i.e. low-power consumption, robustness, high security, and high scalability. Zigbee offers a range of about 10 – 100 meters maximum and data rate to transfer data between communicated devices is around 250 Kbps. Zigbee too has its DIY module named XBee & XBee Pro which can be interfaced with Arduino or Raspberry Pi boards.

(vii) Z-Wave is a communication protocol specially designed for Home Automation products and it is also known as a low-power RF communications technology. The data packets are exchanged at data rates of 100kbps maximum and the protocol operates at a frequency of 900 MHz in the ISM band. It has a distance range of up to 30 meters maximum. It supports control of up to 232 devices. Silicon Labs has a product Z-Wave 700, specially developed for Smart Home applications having features like long battery life (10 years) and improved range to about 100 meters. Also, the company has launched a Z-Wave 700 Development Kit which includes Z-Wave software, sample code and the module with an adapter, enabling others to develop Z-Wave based application products.

(viii) RFID (Radio-frequency identification) is a technology that uses electromagnetic fields to identify objects or tags which contains some stored information. The range of RFID varies from about 10cm to 200m maximum. Since the range has a huge difference, the frequency at which the RFID operates has a huge difference too i.e. it starts from KHz and ranges till GHz or can be said as frequency ranges from Low frequency (LF) to Microwave depending upon the application and distance of communication. RFID has RC522 Arduino & Raspberry Pi compatible module that can be used to build an IoT applications.

(ix) LP-WAN (Low Power Wide Area Network) is used for low power, high range and high bandwidth. Messages sent over LPWAN must be small and simple. Because of their simplicity, these messages can be communicated over the distance without a large power source. Messages that are transmitted over LPWAN sometimes aren't received by the gateway (called packet loss). This can usually be overcome by sending multiple messages or by adding additional gateways to the network, but these solutions have power and financial costs respectively.

Why Effyies?

Effyies are in the business of digitization and automation of industries, micro-grid and homes using IoT technologies. Effyies provides IoT solutions with enhanced security, privacy and transparency integrating block chain technology. Effyies provides customized IoT services tailor made for specific industry ranging from small scale to large scale. Join hands with Effyies and ensure reliable service.

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