The Internet of Things (IoT) is the revolution technology of this decade in information technology. It works by connecting physical devices with the internet. The goal of IoT is to connect the basic services and facilities like smart phones, transportation system, home appliances, watches, sensors, etc. to a common interface so that they all can communicate with each other to provide a better interface. The basic requirement of IoT is wireless communication. There are number of wireless protocols and technologies that can support IoT. The physical devices are connected with each other wirelessly. It gives rise to the machine to machine interface. IoT also require smart devices which are able to connect with other without human intervention . The challenges faced by the IoT are lack of international standards, privacy and trust issues, authentication, etc.
It is a technology in which the communication is achieved with the help of electromagnetic waves. In this type of communication there is generally a transmitter and receiver. A transmitter is used to transmit information with the help of an antenna whereas a receiver is used to receive information with the help of antenna only. There are various technologies that are using wireless communication . IoT generally uses wireless communication to share information . As this technology is growing every day, a standard is set by IEEE for various technologies. All devices that are using this technology have to follow these standards and protocols.
Wireless Technologies in IoT
There are many wireless technologies that are present and they can be used in IoT:
It is a wireless technology developed by Zigbee alliance. It follows IEEE 802.15.4 standard. Due to its short range it is used in close proximity. It is generally used for 10-100 meters. It is used to wireless personal area network (WPAN). Zigbee has low data rate, hence it is mostly used in home automation, collecting data for medical devices, smart energy devices and other application which require low power and low bandwidth. As compared to other wireless technologies Zigbee is simpler and less expensive. The data rate used in Zigbee is 250kbits/sec. Zigbee is used in in applications that require long battery life. The data in Zigbee is secured with 128 symmetric encryption keys. It takes 15ms for Zigbee to respond from sleeping to work mode and 30ms for a node to connect to a network. A master zigbee node can handle up to 254 child nodes .
RF links and NFC
RF links uses radio frequencies for communications. It is also called Radio Frequency Identification (RFID). They are used to identify a specific target using two components known as tag and reader. Tag is generally installed on the target and reader used to read it whenever target comes in the range. It can provide a communication link up to 1km. The range of RFID depends upon the transmission power and the antenna used. It uses electronic chip to transmit data. Power is given to the reader where as there is no power required for the tag. In some cases power tags are also used and hence the operating frequency is increased. The response time for RFID is generally faster. As soon as the tag comes in the range of electromagnetic field it can be detected. The life or durability of RFID is also long. The tag is completely packed, hence there is no chance for any kind of damage.
NFC stands for Near Field Communication. This is also a wireless protocol which is used to transmit and receive data over wireless channel. In this technology, there are two devices one of which is a portable device and it communicate with its port in a close range of 4cm. This is used in payment applications with smartphones. It also used radio frequencies .
Bluetooth and BLE
Bluetooth is used for short range communication. Typical range for bluetooth is within 10m. It was developed by Jaap Haarsten in 1994 working for Ericson. The IEEE standardization for Bluetooth is IEEE 802.15.1. It was one of the first wireless technologies which were originally designed to replace rs232 connectors. It is used where short and cheap communication with low power consumption is required. It can create a personal area network and does not require line of sight for communication. It is very important for the connection of IoT sensors and actuators because the power consumption is key factor. The only disadvantage with Bluetooth is that it cannot be connected to the internet directly. It needs a gateway like a computer to connect with the internet .
BLE stands for Bluetooth low energy. It is an advanced version of the classic Bluetooth. It uses low power as compared to the typical Bluetooth while maintaining the same communication. Cost of BLE is also less than Bluetooth. Most of the current devices like laptops, desktops, smart phones, etc. are using BLE .
Wifi is the short form for Wireless Fidelity. It basically means a local area network which is not wired, hence it is called wireless local area network. If follows IEEE 802.11 standard. Various devices that uses WiFi are personal computers, smartphones, tablets, smart television, printers, smart home appliances, etc. It uses two frequency bands which are, 2.4GHz UHF and 5.8GHz SHF ISM bands. There is no specific range for Wifi. It depends on the power of transmitter and receiver. Any device that came in the range of the transmitter can access the Wifi. This makes it vulnerable for the security as compared with the wired communication. The main advantage of using the WiFi in IoT is that it is very easy to use and access the internet .
It is also known as Worldwide Interoperability for Microwave Access. It is based on the IEEE 802.16 standard. It was one of the alternate technologies used in the 4G communication in place of LTE technology. The general speed provided in WiMAX was 30 to 40 megabit per second. WiMAX was upgraded in 2011 and the speed provided is 1 Gigabit per second.
This wireless communication protocol is widely used in home automation. Z-wave was developed by Zensys in 2001. Typical range of Z-wave is up to 100 metres. It uses 800-900 MHz radio frequency range for communication. It is an open communication protocol. This technology is basically used to send message to the control unit from one or more nodes. There are two kinds of devices involved with Z-wave. One is poll controllers which are used to send commands to the slave devices and other device is used to execute the command .
It is a short form for IPv6 over Low Power Wireless Personal Area Network. This is a very promising protocol for internet of things. It uses IPv6 protocols to send and receive data with IEEE 802.15.4 standard. IPv6 uses 128 bit encryption which is enough to address all the devices in the world . 6LoWPAN is a connection oriented technology.
It stands for Light Fidelity. Like WiFi, this is also a wireless communication technology in which light is used to transmit and receive the information. Visible light spectrum, ultraviolet light and infrared are used to transmit data. This is presently an emerging technology and more research is required on this. The speed in LiFi is much greater as compared to any other wireless technology .
There is no doubt in saying that Internet of Things is the revolution technology and it will grow with a very fast rate. The requirement for IoT is the wireless connectivity. Wired connections are not preferred in IoT. The main reason for that is the ease of access, longer range and low power consumption. The drawback of using wireless communication is the lack of security. Another concern is about the authentication. All the protocols discussed in this paper are for wireless communication. Among those some are in present use and some will be used in future. IoT is still a new and emerging technology and a lot of research and standardization is still required in it.
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