Internet of Things (IoT)

Internet of Things (IoT)

What is an IoT system? An IoT system is a concept of connecting sensors and actuators into a coherent network with Cloud computing services that can provide services to the user.

The Internet of Things (IoT) aims to transform people’s lives through smart homes and businesses. In the home, the goal is a network of connected appliances, lights, climate controls, security, and entertainment systems, all of which work together to make life more convenient and rewarding for consumers. In commercial buildings, IoT aims to improve the efficiency, functionality, automation, and safety of buildings such as offices, healthcare facilities, hotels, and schools. In the consumer market, IoT technology is most synonymous with products pertaining to the concept of the smart home systems.


The IoT devices are connected in a Private Area Network (PAN) using wireless communica- tion protocols. The PAN is then connected through the router(s) to Internet allowing it to accessing the Cloud computing services. The data processed in the Cloud can result in necessity for physical action. The action may be as simple as sending a text message or as complex as activating a set of actuators to accomplish some task.


An IoT system  has following features:

  • Device Identification. An individual device in an IoT PAN has a unique address.
  • Sensing. The IoT PAN has a number of sensing devices that collect data from a monitored event or environment. Examples of sensors include detectors for motion, light, vibration, pressure, temperature, accelera- tion, magnetic field, infrared, proximity, distance, biometric parameters and many others.
  • Response. The IoT PAN may also have a number of devices that respond, that is, perform actions. Examples include relays, actuators and switches.

  • Communication. The IoT devices in the PAN communicate wirelessly with each other. The sensor data are communicated, by the router, to a central location, usually using Cloud computing, for processing and evaluation. Results of data evaluation are then communicated back to the IoT PAN for any required physical action.

  • Computation. Cloud computing services are usually used to process the IoT sensor data. Cloud computing formulates a response and sends to the IoT router, if needed. The IoT router then uses the PAN wireless communication links, to deliver the message.

  • Services. The IoT PAN is ubiquitous and provides a number of services: item identification, collecting and communicating sensor data, event monitoring, performing physical action(s), and device collaboration.

  • Semantics. Cloud processing software analyzes the data and provides a context-aware response for the IoT system.


All these capabilities in the IoT PAN are provided under practical constraints. Some of the major constraints on the IoT PAN are:

  1. Low power. Many of IoT devices are battery powered; replacing bat- teries is expensive, inconvenient, and unreliable. Even if the IoT devices are attached to the power grid, low power is required for a couple of reasons. First, the IoT devices are continuously operating and therefore even small amount of power consumption can quickly add up. Second, a typical IoT installation consists of hundreds of devices. The aggregate power consumption of these devices operating continuously can be quite significant.
  2. Low cost. Cost is always a major factor in the consumer adoption of any product. Low cost promotes a wider use of the smart technologies.
  3. Security. Beside physical security of the IoT devices, authenticity, pri- vacy, confidentiality, and integrity of data are important consideration in an IoT system.
  4. Communication. The IoT faces communication constraints on mul- tiple fronts. The IoT PAN radio operates on low power, short range transmission, in a restricted public frequency spectrum. The operating environment is noisy with other equipment generating radio interfer- ence, and there are many physical obstacles. The IoT communication also faces the challenge of frequent network route changes as IoT


IoT Private Area Network

There are a number of IoT protocols currently available, Z-Wave, ZigBee, Thread, IoTivity, AllJoyn, and among others. Although particulars for each of these protocols are different, they share many similarities. All these protocols establish a wireless Private Area Network (PAN). PAN network topology is built using connectivity through wireless radios. Topologies commonly used for PAN are point-to-point, star and mesh. The mesh topology is the most popular due to its robustness, scalability and fault resilience. A typical PAN with mesh topology can be seen in Figure 11.1. Generally, an IoT network have three types of nodes: End devices, PAN routers, Border routers. Data from IoT devices can be transmitted across multiple hops, as determined by a routing protocol, before arriving at gateway Border router(s). The End devices normally consist of sensors or actuators. The PAN routers serve multiple purposes, besides being sensors or actuators, PAN routers also act as communication router for the End devices. The PAN routers have additional capability to connect with other PAN routers and/or Border routers. The Bor- der router(s) have an additional capability to act as gateway to Internet/Cloud by connecting to Internet router. The End devices can communicate with either the PAN network router or directly with Border routers. An example of a Border router is Nest thermostat, which has connectivity to both PAN and Wi-Fi router, plus it is also an IoT sensor and actuator.