IoT comments What are overheads, headers and payloads? You are expected to understand how the data being transmitted is organized How does the overhead information affect the proportion of useful data transmitted How does this affect bandwidth utilization? Frequency, interference, antenna, beamforming , antenna arrays --> please look them up especially if you are new to networks and communications ********************************************* Depending on the modulation type we may have different data rates. We have not done modulation in the course though It is a way of coding the data to transmit the more bits that can be transmitted by a modulation scheme the higher the data rate ******************************************** Spreading factor is used in Code division multiple access (CDMA) technologies. They generally use Spread spectrum technology . In this technology, the data rate of an input signal is increased using another fast signal called a chirp In DSSS - Direct Sequence Spread Spectrum, each bit is multiplied by the chirp. In effect the data rate is multiplied by the spreading factor ********************************************** Note on this slide that what is doing the trick in Bluetooth is software the algorithm. This is communication software which is a specialized field on its own ********************************************* Would be good to find out what Amazon Echo, Dash, Apple Siri, Google Home do Realise that Amazon, Google and Apple and competing in this space as well Note: These products have become possible because AI, ML, Analytics are happening right on the edge device. This is an interesting and emerging area of research Are Edge and Fog computing replacing cloud computing? Does the Cloud still have a place in IoT systems? How has the use of the Cloud changed with the advent of Edge/Fog computing? *********************************************** What is the distance range for Short range? Medium range? How does licensed or unlicensed band affect the following: device approval, cost, quality of service and time to market? *******************Which technologies operate in unlicensed band and which ones operate in the licensed bands. Which ones operate in both? Is there a possible trade-off? How does the frequency band (magnitude) affect range or coverage **************************** So a large packet is divided at the source and transmitted and these packet slices are reassembled at the destination to reconstruct the complete packet. Also, every technology has a maximum limit on data. So by segmentation and reassembly we are able to cope with this limitation ********************************************* data rate: the rate at which bits are transmitted. In some LANs (eg Wi-Fi) the data rate can vary with time. they are generally measured in kilobits per second (kbps) or megabits per second (Mbps) Throughput refers to the overall effective transmission rate, taking into account things like transmission overhead, protocol inefficiencies and perhaps even competing traffic. It is generally measured at a higher network layer than the data rate. Throughput is always less than the data rate due to factors such as latency affecting throughput bandwidth is mostly used as a synonym for data rate. The term comes from radio transmission, where the width of the frequency band available is proportional to the data rate that can be achieved. **************************************** when selecting an acess technology, we should consider the issue of latency. however, we can implement deterministic data paths for real-time applications with extremely low data loss rates, packet delay variation (jitter), and bounded latency, such as audio and video streaming, industrial automation, and vehicle control. IEEE Std 802.15.4-2003 defined the protocol and compatible interconnection for data communication devices using low-data-rate, low-power ***************************************** When data is sent over the Internet, each unit transmitted includes both header information and the actual data being sent. The header identifies the source and destination of the packet, while the actual data is referred to as the payload. Because header information, or overhead data, is only used in the transmission process, it is stripped from the packet when it reaches its destination. Therefore, the payload is the only data received by the destination system. ******************************************** Small devices with limited CPU, memory, and power resources, so called constrained devices (also known as sensor, smart object, or smart device) can constitute a network, becoming “constrained nodes” in that network. Such a network may itself exhibit constraints, e.g. with unreliable or lossy channels, limited and unpredictable bandwidth, and a highly dynamic topology. *********************************************** QUIZ 2 Part B Q1: 1a. 6LoWPAN - IPv6 over Low -Power Wireless Personal Area Networks. b. LLN - Low-Power And Lossy Networks c. Wi-SUN - Wireless Smart Ubiquitous Network Q2 a. IEEE 802.11 - WiFi technology b. IEEE 802.15.4 - wireless access technology for low-cost and low-data-rate devices that are powered or run on batteries c. IEEE 802.11ah - Wi-Fi and low-power sensor network communication technologies. technology built on the well-known 802.11 Wi-Fi standards that is specifically for smart objects. d. IEEE 1901.2a – a technology for connecting smart objects over power lines. wired technology that is an update to the original IEEE 1901.2 specification. This is a standard for Narrowband Power Line Communication (NB-PLC) Q3 a. Routing protocol used in P2P network Mobile Peer control protocol (MPCP), EDSR( Encryption based dynamic and secure routing) b. encryption/ security standard in iot networks The IEEE 802.15.4 specification uses Advanced Encryption Standard (AES) with a 128-bit key length as the base encryption algorithm for securing its data. Q4 a. Frequency is inversely proportional to range, so A will have longer range b. The higher the frequency the higher the data rate, so B the sub-GHz frequency bands allow greater distances between devices. These bands have a better ability than the 2.4 GHz ISM band to penetrate building infrastructures or go around obstacles, while keeping the transmit power within regulation. Adv: Because of the long range and low power consumption, sub-GHz networking is particularly well-suited to Internet of Things applications. Single-chip solutions for sub-GHz networking are widely available at low costs. The disadvantage of sub-GHz frequency bands is their lower rate of data delivery compared to higher frequencies. However, most IoT sensors do not need to send data at high rates. Therefore, the lower transmission speeds of sub-GHz technologies are usually not a concern for IoT sensor deployments. Q6 Adaptive Data Rate (ADR) is a mechanism for optimizing data rates, airtime and energy consumption in the network. ADR should be enabled whenever an end device has sufficiently stable RF conditions. This means that it can generally be enabled for static devices. If the static end device can determine that RF conditions are unstable (for example, when a car is parked on top of a parking sensor), ADR should (temporarily) be disabled. Mobile end devices should be able to detect when they are stationary for a longer times, and enable ADR during those times. End devices decide if ADR should be used or not, not the application or the network. Q8: Features 802.11ah 802.15.4 *Suitable applications: -Smart city, Smart home -Smart agriculture, Environment monitoring *Network support -Sensor, Backhaul -Sensor *Frequency -Sub-1 GHz -2.4 GHz, Sub-1 GHz *Channel access -RAW -CSMA/CA *Data rate (maximum) -78 Mbps (16 MHz in Sub-1 GHz) -250 Kbps (2 MHz in 2.4 GHz ) *Range (maximum) -1000 m (without repeaters) -100 m (without repeaters) *Power saving -TIM, DTIM, TWT -Sleep–wake strategy *Relay feature -Relay AP -Full Function Device (FFD) The licensed-band technologies are dedicated to mobile service providers that have acquired spectrum licenses The main challenge faced by providers of the licensed bands is the opportunity for non-mobile service providers to grab market share by offering IoT infrastructure without buying expensive spectrum. LPWA communications are able to cover long distances that in the past required the licensed bands offered by service providers for cellular devices. Using a licensed spectrum has two significant benefits: greater reliability and better performance. Companies using unlicensed bands for IoT deployments run into reliability and performance issues more frequently than those using licensed spectrum, in part because they simply can’t control what other people do. Cellular IoT, LTE, 3G, and narrowband IoT (NB-IOT) technologies use licensed bands, In a P2P network, the "peers" are computer systems which are connected to each other via the Internet. Files can be shared directly between systems on the network without the need of a central server. In other words, each computer on a P2P network becomes a file server as well as a client. The only requirements for a computer to join a peer-to-peer network are an Internet connection and P2P software. Common P2P software programs include Kazaa, Limewire, BearShare, Morpheus, and Acquisition. These programs connect to a P2P network, such as "Gnutella," which allows the computer to access thousands of other systems on the network. Once connected to the network, P2P software allows you to search for files on other people's computers. Meanwhile, other users on the network can search for files on your computer, but typically only within a single folder that you have designated to share. While P2P networking makes file sharing easy and convenient, is also has led to a lot of software piracy and illegal music downloads. Therefore, it is best to be on the safe side and only download software and music from legitimate websites.
