Internet of Things (IoT)

Overview

Internet of Things (IoT) is a network of devices that connect to and communicate via the internet or other communication networks. These devices collect, exchange, and act on data, often without human intervention. It enables enhanced interactivity and automation across various domains, from smart homes to industrial applications.

IoT Deployment

The components of a typical IoT network are:

• Embedded Devices & Sensors: Integral components that detect changes in the physical environment.
• IP Network Communication: Facilitates data transmission between devices and cloud servers
• Cloud Integration: Incorporates services like Big Data, Analytics, and Machine Learning in the cloud.

The sensors used in NetSim are abstract, which means that they could be any kind of sensor or embedded device. These sensors are assumed to sense some physical property or random “field” such as temperature, pressure etc. After sensing the sensors transmit the sensed data in the form of “IP Packets' ' of user settable size and user settable interpacket arrival time. NetSim simulates the transmission of these IP packets over an IoT network. It does not focus on the actual “application payload (or the sensed data)” being sent and is not concerned with data storage and analytics of this payload.

Fig: A typical IOT scenario in NetSim. The wireless sensor network can be created using the Auto placement utility.

NetSim IoT /WSN stack

• Application Layer: Sensor App as well as applications such as Voice, Video, CBR etc.
• Transport Layer: UDP
• Network layer: Muli-hop ad hoc routing protocols AODV and RPL
• MAC and PHY layers: IEEE 802.15.4 Zigbee
• Energy module: Models power usage during transmission, reception, and idle states, as well as energy harvesting capabilities

NetSim models IoT as a WSN that connects to an Internetwork through a 6LowPAN Gateway. The 6LowPAN Gateway uses two interfaces: a Zigbee (802.15.4) interface and a WAN Interface. The WSN sends data to a 6LowPAN Gateway. The Zigbee interface allows wireless connectivity to the WSN while the WAN interface connects to the external Internetwork.

Fig: A typical application scenario that can be modeled in NetSim. Sensors can generate (measurement) packets that get queued in its packet buffer. These are then transmitted - directly or via hops - over a wireless link to a gateway that then forwards the packet via the internet to a server. Wireless links support various propagation models and ad hoc routing is supported for multi-hop communication. The MAC/PHY layer protocol supported is 802.15.4.

IEEE 802.15.4 uses either Beacon Enabled or Disabled Mode for packet transmission. In Beacon Enabled Mode, nodes use slotted CSMA/CA algorithm for transmitting packets else they use Unslotted CSMA/CA.

Network Performance Metrics and Log Files

Fig: The Result dashboard and Plot window shown in NetSim after completion of simulation

NetSim provides a wide range of tabular and graphical performance measures. The tabular presentation includes end-to-end delays, jitter, errors, packets generated / received / collided, route tables, TCP Acks, retransmissions etc.

Results are organized per interface, per device, per application and per link. In addition, summary metrics are aggregated and presented system-wide (network-level). Information in the trace files contain individual packet flow and individual event execution. Protocol log files record a myriad of information pertaining to protocol operation necessary for in-depth analysis. The Radio-Measurements file records pathloss, shadow fading loss, received power, SNR, Interference Power, SINR and more.

The results can be exported as a .csv file and opened in a spreadsheet software like Excel.

Wireshark Interfacing: pcap files can be recorded at each node which can be opened in Wireshark for protocol analysis

MATLAB Interface: NetSim can be interfaced with MATLAB offline or online (run-time)

Additional Information:
Knowledgebase Q&A
File Exchange Link
Webinar Link
Research on Low Power WSNs using NetSim