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ABSTRACT
This paper discusses an overview about Internet of Things Iot, Wireless Connectivity Technologies.The concept IoT is the future vision of Internet where every physical device, people, machines are connected to a network giving immediate access to information about physical world.In the present world scenario each and every device is connected to internet, exchanging information about their surroundings and themselves. Every device uses a communication protocol to connect to a network. Enabling wireless technologies like RFID tags, embedded sensor devices, smart sensors, and mobile are a revolution for future IoT.This paper provides a technical standards overview of different standards like IEEE, IETF and ITU for IoT enabling wireless technologies. Introduction of Wi-Fi, ZigBee, Z-wave, Bluetooth, LTE-Advanced,WPAN technologies.Present a complete service use-cases to demonstrate how different technologies suit to deliver Iot services.
INTRODUCTION
The word Internet of Things means a wide network of interconnected physical things with unique identity having standard communication protocol [1].Realizing the concept of Internet of Things (IoT) there is a huge growth day by day the number of physical device which are being connected to the Internet. In this process of rapid growth each and every sensor, industrial machines, personal gadgets, medical applications are being connected to internet providing variety of use-cases in every possible environments serving Internet of Things (IoT). Among the multiple wireless communication protocols available with multiple frequencies, the right choice among them is challenging. Internet of Things is a revolution for modern applications enabling Wireless Communication Technologies. The idea behind the concept came from the increased number of RFID tags, mobiles and sensors with unique identity, interacting with each other and sharing their surrounding information [2]. IoT is playing a vital role in sectors like healthcare, industries, transportation, business applications, home automation and security improving our quality of living standards. The outline of this paper is summary on LTE-A, Wi-Fi, ZigBee, Z-wave, Bluetooth protocol standards and specifications, overview of use-cases to demonstrate how each protocol fits IoT services.
This paper is structured as Chapter 2 explains Iot Architecture. Chapter 3 includes summary of Wi-Fi, ZigBee, LTE-A, Z-wave, Bluetooth protocol standards and specifications and their comparison. Chapter 4 reviews application use-cases for IoT in various sectors. Chapter 5 concludes our discussion.
Wireless Technologies
Internet of things is a global network relaying on networking, wireless technologies, sensors and actuators for connecting numerous devices and maintaining communication [6]. RFID and WSN technology are the roots of IoT, which enables to detect identity, maintain track of objects using their tags and special intelligent sensors. [7].Standardization is very important for the success of Iot. International Telecommunication Union, IEEE, Internet Engineering Task Force and many other organizations are working together on standardization for IoT for future development[8][9].
Z-Wave
Firstly a Danish company Zensys developed Z-Wave, it was acquired by Sigma Designs. It operates using 908 MHz in USA and 868 MHz in Europe with data rate from 9.6-40kb/s using binary frequency shift keying modulation. It is a low power MAC protocol which is designed for home automation purpose and Iot communication especially for smart homes. Z-Wave can cover up to 30m point to point communication which is good for applications like light control, wearable health control. The architecture consists of a master and slave in which master controls the slave, and has control of scheduling of the whole network. There are five main layers PHY, MAC, Transfer, Routing and Application Layer. The Z-Wave 400 series chip supports the 2.5 GHz band with bit rate up to 200kb/s. the Mac layer of Z-Wave consists a collision mechanism which allows the transmission of a frame whenever a channel is available otherwise the attempt is delayed for a certain period of time. Communication between two consecutive nodes is managed by the transfer layer. The routing layer performs routing which is based on source routing approach. Each packet can be transmitted up to four hops. A controller will maintain a table to represent the topology of the network.
ZigBee
ZigBee technology is named after the Waggle Dance of bees when returning to hives after a field fight, communicating the distance and type of food they found. This relates to the mesh nature of the ZigBee, where data hop from node to node. ZigBee is a remote systems administration innovation by the ZigBee Alliance for low-data rate and short-range applications. ZigBee convention stack is made out of four fundamental layers: Physical layer, MAClayer, Network layer, and Application layer. ZigBee is based on the initial version of IEEE 802.15.4 which operates in 868 MHz with data rate 20kb/s, 915 MHz with data rate of 40 kb/s, and 2.4 GHz with data rate of 250 kb/s. orthogonal –quadrature phase shift keying is used for the 2.4 GHz signals and Binary phase shift keying is used for 915 MHz and 868 MHz signals. Beacon enabled and beaconless are the two methods of channels available in IEEE 802.15.4.Network layer specifically supports addressing and routing for mesh and tree topologies. The tree topology is rooted at the ZigBee coordinator whereas in a mesh topology roots are created on demand. Only ZigBee routers and coordinators can participate in routing operations.
Wi-Fi
Wi-Fi technology is developed based on IEEE 802.11 standard in replacement of the wired Ethernet technology based on IEEE 802.3 standard.Despite the fact that Wi-Fi innovation essentially defines the link layer of a local system, it is also integrated with the TCP/IP stack, that when individuals say they are utilizing Wi-Fi they certainly imply that they are likewise utilizing a TCP/IP for Internet availability.Wi-Fi is coordinated into every new portable PC, tablets, cell phones and TVs. Exploiting the existing limitless conveyed framework in homes and venture, Wi-Fi's next step is to interface the new things to the Internet.Wi-Fi networks operate in ISM 2.4GHz band. For enabling high data rates over 100Mbps, power consumption is more. Using silicon devices with advanced sleep protocols and fast on and off time can reduce the average power consumption. Every Iot device does not need maximum data rate, by managing power management design we can keep devices connected to the internet for over years using an alkaline battery. Each standard Wi-Fi access points can support up to 250 devices connection simultaneously, and with an enterprise grade access point we can achieve more number of connections.
Bluetooth
Bluetooth technology has been invented by Ericsson in 1994 and is named after a scientist Scandinavian King. Previously link layer of Bluetooth operating in 2.4GHz ISM band was an IEEE 802.15.1 standard, currently it is replaced with Bluetooth SIG. Basic rate and low energy are the two forms of systems Bluetooth offers. Basic rate has a data rate of 721.2Kbps to 2.1Mbps where low energy has a data rate of 1Mbps and aims for low power consumption. Bluetooth technology is a personal area networking which is used in place of cables for short range communications. It is used in star and point to point network topologies. Bluetooth smart is the recent upgrade for Bluetooth specifications which enables low energy consumption. Bluetooth classic can connect up to eight devices in a star network topology where as in Bluetooth low energy we can connect as many devices available in the range. Bluetooth turned out to be extremely fruitful in cellular telephones, so much that every single cellular telephone today, even intermediate level telephones, have Bluetooth availability. The primary use case that made Bluetooth well known at first was handsfree telephone calls with headsets. From there on, as cellular telephones turned out to be more proficient, more utilize cases like music streaming has evolved.
LTE-A
Long term Evolution Advanced is a communication standard which is designed for cellular networks. LTE-A operates using Orthogonal Frequency Division Multiple Access which divides the frequency into multiple bands and use separately. The architecture of LTE-A has a radio network, mobile nodes, and a core network. Core network maintains full control of mobile devices keeping track of their IP’s, radio network controls data planes and maintain wireless connections and radio access control. LTE-A has a channel width up to 100MHz operating with frequency band of 450MHz to 4.99GHz. It has a Bit rate up to 1Gbps and has a range up to 30km. LTE-A has Ubiquitous coverage with very high capacity. LTE-A has a mobility support as high as 35km/hr. with a potentially high market penetration. LTE-A offers a high uplink 751Mbps and downlink 300Mbps capacity.
COMPARISION
Considering some of the specifications of the wireless technologies let us compare them with different technologies discussed in the paper. Some of the key specifications on which we are concentrating are network topologies, maximum date rate, range, error control, transmitting power, security, Bit rate ,Mac mechanism, Modulation, identification. Table.1. summarizes the key specifications of Bluetooth, Wi-Fi, LTE-A, ZigBee, and Z-Wave
ZigBee is one of the open standard Networking Technology standard based on IEEE 802.15.4, having by more than 10 chip vendors. ZigBee provides long battery life, improving the life of the product. ZigBee operateson worldwide 2.4 GHz frequency band.
Wi-Fi enables high data rate to support internet data sharing and distribution. Wi-Fiis a worldwide accepted open standards based on IEEE 802.11. Wi-Fi provide high speed, high data rate communications.Bluetooth is the standard for short range, low data rate wireless technology connecting a wide range of devices. Bluetooth is worldwide accepted open standards based 802.15.1.ZigBee and Bluetooth smart will dominate the low power network devices market.
Chapter 4
Applications
In this chapter, we discuss application use-cases to point out how different technologies discussed in the paper fit to deliver Iot functionality.
InMedical Monitoring System we need to collect the information of patients vital sign measurements and deliver them to nursing station. Assuming that the patient is suffering with depression we deployed a door and light sensor. For implementing such functionality, a developer can choose sensors that are embedded with ZigBee or Z-wave for communication in order to collect the measurements from sensor and use their access points for building an application that pulls the collected data to the station. To transmit data to doctors remotely, a mobile application can be develop and by using a MQTT client and broker we can fetch the data by subscriptions through a LTE-A connection.
In Bluetooth low energy the internet service is a GATT-based service that resides in the gateway and allow the device to access internet by using standard internet protocol like HTTP. This gateway can be used to connect any device with internet service client.To read and write data from database the Bluetooth device connected to gateway uses internet services.A smart phone can act as a gateway accessing the database through its GSM, 3G, and 4G connections. GAP/GATT are some of the methods used to access GATT-based Bluetooth devices by using internet. They allow to read, write and subscribe data for notifications. Devices are connected to a gateway and does not need to have the information about service/profile. This can be applied in home automation or home care, wearables, fitness.
The number of devices getting connected to Wi-Fi are rich in display, keyboard and other abilities which make entering information easy. Small devices in present world being added to office, home, industries do not have convenient data entry options to configure them. Thus these devices need to be embedded with smart devices to configure them. A coffee-maker with a Wi-Fi option need to know the SSID to connect to the network as a client to allow the users to turn it on and off from a remote location, get notification on completion of brewing, changing temperature etc. By enabling a WPS button on coffee machine and router we can access the coffee maker remotely. By using SSID of coffee maker we can identify the device easily.
The latest LTE-A support use cases in the field of automotive, wearables, health care, smart cities. Street light automation, smart parking, home energy management, security surveillance.
Future Prediction
Availability of smart phones and wireless technologies which are energy efficient and cheap made automation simple. Every wireless technology adapting a standard has achieved IoT devices. Compared to Z-Wave and ZigBee Bluetooth is old technology with smart phone connectivity which is highly beneficial. Wi-Fi is embedded in millions of devices and