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Semester 3: B.Sc Internet of Things
Introduction to RFID systems, components, operating principles
Introduction to RFID systems
Definition and Overview
RFID stands for Radio Frequency Identification. It is a technology that uses radio waves to automatically identify and track tags attached to objects.
Components of RFID systems
An RFID system consists of three main components: the RFID tag, the RFID reader, and the backend system. Tags may be active, passive, or semi-passive. Readers capture the tag data and transmit it to the backend system for processing.
Operating Principles
RFID systems operate based on radio frequency communication. The reader emits an electromagnetic field that activates the tag, which then transmits its stored information back to the reader.
Applications of RFID
RFID is used in various applications such as inventory management, asset tracking, access control, and supply chain management.
Advantages and Disadvantages
Advantages of RFID include automation, improved accuracy, and real-time data collection. Disadvantages may involve cost, privacy concerns, and interference issues.
Frequency ranges, coding, modulation, data integrity, security of RFID systems
Frequency ranges, coding, modulation, data integrity, security of RFID systems
Frequency Ranges
RFID systems operate in various frequency ranges: Low Frequency (LF): 125-134 kHz; High Frequency (HF): 13.56 MHz; Ultra High Frequency (UHF): 860-960 MHz; Microwaves: 2.45 GHz to 5.8 GHz. Each frequency band has its advantages and limitations in terms of range, data transfer speed, and environmental impact.
Coding
RFID systems use various coding techniques to ensure unique identification. Common coding schemes include: Binary Coding: Using binary digits to represent data. Gray Code: Reduces errors in digital communication. Manchester Encoding: Combines clock and data signals for improved synchronization.
Modulation
Modulation techniques in RFID are crucial for effective data transmission. Common methods include: Amplitude Shift Keying (ASK): Varies the amplitude of the carrier wave. Frequency Shift Keying (FSK): Varies the frequency of the carrier wave. Phase Shift Keying (PSK): Varies the phase of the carrier wave.
Data Integrity
Data integrity in RFID systems ensures accurate data capture and transmission. Techniques include: Error Detection Codes: Parity checks and checksums to identify data corruption. Data Validation Mechanisms: Cross-referencing received data with expected values.
Security
Security measures in RFID systems are vital due to privacy concerns. Key strategies include: Encryption: Protects data during transmission using algorithms. Access Control: Ensures only authorized devices can access RFID data. Anti-cloning Techniques: Prevents duplication of RFID tags.
Wireless Sensor Networks: Node architecture, physical layer, MAC layer protocols
Wireless Sensor Networks: Node architecture, physical layer, MAC layer protocols
Node architecture
Wireless Sensor Nodes typically consist of four main components: sensing, processing, communication, and power supply. The sensing unit contains sensors to collect data from the environment. The processing unit, usually a microcontroller, processes the data and determines actions based on predefined algorithms. The communication unit is responsible for transmitting the data wirelessly, using various protocols depending on the application. The power supply manages energy efficiency and can include batteries or energy harvesting components.
Physical Layer
The physical layer in Wireless Sensor Networks defines the transmission medium and the technology used for communicating data. It focuses on the physical ones and zeros of communication. Common technologies include Zigbee, Bluetooth, and LoRa. The physical layer is crucial as it directly affects the range, data rate, and power consumption of the sensor networks, which are critical aspects in battery-powered devices.
MAC Layer Protocols
Medium Access Control (MAC) protocols manage how devices in a network share the communication medium efficiently. In Wireless Sensor Networks, MAC protocols must consider energy efficiency, reliability, and latency. Examples include CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), TDMA (Time Division Multiple Access), and FDMA (Frequency Division Multiple Access). Each protocol has its own advantages and is chosen based on the network requirements and application scenarios.
Security in WSN: Attacks, protocols, IEEE 802.15.4 and ZigBee security
Introduction to WSN Security
Wireless Sensor Networks (WSNs) are vulnerable to various security threats due to their wireless nature and resource constraints. Securing these networks is essential to ensure data integrity, confidentiality, and availability.
Types of Attacks on WSN
Common attacks include: 1. Eavesdropping - Interception of communication. 2. Jamming - Disruption of communication. 3. Sinkhole Attacks - Deceptive routing by compromising nodes. 4. Sybil Attacks - Nodes presenting multiple identities.
Security Protocols for WSNs
Security protocols aim to provide authentication, encryption, and integrity services. Protocols like Secure Sensor Network Protocol (SSNP) and TinySec have been designed for energy-efficient security.
IEEE 802.15.4 Security Features
IEEE 802.15.4 provides a standard for low-rate wireless personal area networks (LR-WPANs). It includes mechanisms for security including AES-128 encryption, access control, and key management.
ZigBee Security Model
ZigBee builds upon IEEE 802.15.4 to add security features. It employs a security framework that includes encryption, authentication, and integrity checks to ensure secure communication in IoT applications.
Challenges in WSN Security
Key challenges include limited energy resources, scalability, and the dynamic nature of WSNs. These factors complicate the implementation of robust security measures.
