Chapter 1-Introduction to wireless communication systems

[Pages:36]Chapter 1 Introduction to Wireless Communication Systems

School of Information Science and Engineering, SDU

Outline

l Wireless History l The Wireless Vision l Technical Challenges l Wireless definitions l Classification of Wireless Systems l Modern Wireless Systems and Trends

Wireless History

l Ancient Systems: Smoke Signals, Carrier Pigeons, ... l Radio invented in the 1880s by Marconi l Many sophisticated military radio systems were

developed during and after WW2 l Cellular has enjoyed exponential growth since 1988

l Ignited the wireless revolution l Voice, data, and multimedia becoming ubiquitous l Use in third world countries growing rapidly

l Wifi also enjoying tremendous success and growth l Wide area networks (e.g. Wimax) l Short-range systems: Bluetooth, UWB, ...

The Wireless Vision

l Next-generation Cellular l Wireless Internet Access l Wireless Multimedia l Sensor Networks l Smart Homes/Spaces l Automated Highways l In-Body Networks l Internet of things l All this and more

Technical Challenges

l Network Challenges

l Scarce spectrum l Demanding/diverse applications l Reliability l Ubiquitous coverage l Seamless indoor/outdoor operation

l Device Challenges

l Size, Power, Cost l Multiple Antennas in Silicon l Multi-radio Integration l Coexistence

Wireless System Definitions

l Mobile Station

? A station in the cellular radio service intended for use while in motion at unspecified locations. They can be either handheld personal units (portables) or installed on vehicles (mobiles)

l Base station

? A fixed station in a mobile radio system used for radio communication with the mobile stations. Base stations are located at the center or edge of a coverage region. They consists of radio channels and transmitter and receiver antennas mounted on top of a tower.

Wireless System Definitions

l Mobile Switching Center

? Switching center which coordinates the routing of calls in a large service area. In a cellular radio system, the MSC connections the cellular base stations and the mobiles to the PSTN (telephone network). It is also called Mobile Telephone Switching Office (MTSO)

l Subscriber

? A user who pays subscription charges for using a mobile communication system

l Transceiver

? A device capable of simultaneously transmitting and receiving radio signals

Wireless System Definitions

l Control Channel

? Radio channel used for transmission of call setup, call request, call initiation and other beacon and control purposes.

l Forward Channel

? Radio channel used for transmission of information from the base station to the mobile

l Reverse Channel

? Radio channel used for transmission of information from mobile to base station

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