Cognitive Radio Introduction
- 1. Mrs.G.Gnana Priya Assistant Professor(Sr.Gr.)/ECE Ramco Institute of Technology Introduction to Cognitive Radios
- 3. • Communication is the process of establishing connection between two points for information exchange (i.e) Basic process of exchanging information from one location (source) to another location (destination). 3 Introduction to Communication Systems Source Destination Information
- 4. 4 Elements of a Communication System • Basic block diagram of a communication system: Information Source Transmitter Channel (Transmission Medium) Noise & Distortion Receiver Destination
- 5. Electronic Communication Systems Direction of Communication Nature of Information Signal Half Duplex Full Duplex Analog Digital Unidirectional Bidirectional Simplex Techniques of Transmission Baseband Transmission Communication using Modulation Classification of Electronic Communication Systems
- 6. Advantages and disadvantages of wireless communication • Advantages: – Mobility – A wireless communication network is a solution in areas where cables are impossible to install (e.g. hazardous areas, long distances etc.) – Easier to maintain • Disadvantages: – Has security vulnerabilities – Unlike wired comm., wireless comm. is influenced by physical obstructions, climatic conditions, interference from other wireless devices
- 11. “Learning” to Adopt is the only Solution
- 18. Introduction The radio spectrum is divided into licensed and unlicensed frequencies. • The licensed spectrum is for the exclusive use of designated users. For instance, it includes the UHF/VHF TV frequency bands. • The unlicensed spectrum can be freely accessed by any user, following certain rules (e.g., not exceeding a defined limit for transmission power). It includes, for instance, the ISM (Industrial, Scientific and Medical) and U-NII (Unlicensed National Information Infrastructure) frequency bands. ISM is shared by technologies such as IEEE 802.11 for wireless local area networks (WLANs), Bluetooth.
- 21. Bodies work on Standards for Radio Frequency Allocation
- 22. 3 Categories of Radio Frequency bands
- 23. Radio waves generation • When a high-frequency alternating current (AC) passes through a copper conductor it generates radio waves which are propagated into the air using an antenna • radio waves have frequencies between: – 3 Hz – 300 KHz - low frequency – 300 KHz – 30 MHz – high frequency – 30 MHz – 300 MHz – very high frequency – 300 MHz – 300 GHz – ultra high frequency