1. Communication systems Dr. Bahawodin Baha School of Engineering University of Brighton, UK July 2007

2. Block diagram of a Communication System

3. COMMUNICATION SYSTEMS Provide electronic exchange of multimedia data, Voice, data, video, music, email, web pages, etc. Communication Systems of today Radio and TV broadcasting, Public Switched Telephone Network (voice, fax, modem) –Cellular Phones –Computer networks (LANs, WANs, and the Internet) –Satellite systems (pagers, voice/data, movie broadcasts) –Bluetooth

4. Provide electronic exchange of multimedia information The information to be transmitted is electromagnetic wave or electrical signal may represent: multimedia data, Voice, data, video, music, email, web pages, etc. The frequency bandwidth occupied by the information signal is called the baseband, and the signal is often referred to as the baseband signal. Channel – is the medium by which the transmitted signal is propagated: Various layers of atmosphere, cable for telephone or date link, cable TV or Electrical signals are converted to a corresponding light signal that is propagated through a fiber optic channel

5. Electromagnetic Spectrum

6. Based on these conditions, the radio spectrum is divided into the following sub bands: Extra Low Frequency (ELF)300 – 3000 Hz (l =1000 – 100km) Very Low Frequency (VLF)3 – 30 kHz (l = 100 – 10 km) Applications: mining, underwater communication (submarine), Sonar Low Frequency (LF)30 – 300 kHz (l = 10 – 1 km) Applications: broadcasting, radio navigation Medium Frequency (MF)300 – 3000 kHz (l = 1000 – 100 m) Applications: AM radio broadcasting (550 – 1600 kHz) High Frequency (HF)3 – 30 MHz (l = 100 – 10 m) Applications: Broadcasting over large areas, amateur radio (ham), citizens band (CB) radio. Very High Frequency (VHF)30 – 300 MHz (l = 10 – 1 m) Applications: TV, FM radio (88 –1108 MHz ), radio beacons for air traffic control Ultra High Frequency (UHF)300 – 3000 MHz (l = 1 m – 10 cm) Applications: broadcasting, satellite (TV) broadcasting, all (1G to 3G) land mobile telephones, cordless telephones, some air traffic control. Super High Frequency (SHF)3 – 30 GHz (l = 10 – 1 cm) Applications: Satellite service for telephony and TV, mobile services in the future Extremely High Frequency (EHF)30 – 300 GHz (l = 10 – 1 mm) Applications: communications at short distances (within Line-Of-Sight), broadcast satellite for HDTV (for satellite communication between satellites in space, not space to earth).

7. Communication theories Communication systems send and receive information electronically over communication channels Modulation Demodulation Amplification Filtering Signal detection Digital Signal Processing, DSP

8. Wireless Communication Objectives: Multimedia wireless Communications at any Time and Anywhere Brief history Ancient Systems: Smoke Signals, Carrier Pigeons Radio invented in the 1880s by Marconi Many sophisticated military radio systems were developed during and after WW2 Cellular has enjoyed exponential growth since 1988, with more than 1 billion users worldwide today Ignited the recent wireless revolution, 1980-2003 Growth rate tapering off Is there a future for wireless?

9. Design Challenges Hardware Design Precise components Small, lightweight, low power Cheap High frequency operations System Design Converting and transferring information High data rates Robust to noise and interference Supports many users Network Design Connectivity and high speed Energy and delay constrains

10. Main Points Introduction to Communication Systems Block diagram of a Communication System Electromagnetic spectrum Main theories Wireless and mobile Communications Design challenges include hardware, system and network issues

11. The END http://www.uobkupartnership.talktalk.net