Lec8_Antennas_MIMO_11n (1) - Multiple-Input and Multiple-Output(MIMO and 802.11n(Ch 15 of Textbook Instructor Dr Wei(Lisa Li Computer Science GSU

Lec8_Antennas_MIMO_11n (1) - Multiple-Input and...

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Multiple-Input and Multiple-Output (MIMO) and 802.11n (Ch. 15 of Textbook) Instructor: Dr. Wei (Lisa) Li Computer Science, GSU [email protected]
--- A method for multiplying the capacity of a radio link using multiple transmit and receive antennas to exploit multipath propagation MIMO
An Overview 802.11a/b/g devices send a single spatial stream over a single antenna If signals are reflected, there is a problem To further improve throughput Transmit two or more spatial streams, and employ multiple receive antennas and advanced signal processing to recover the multiple transmitted data streams Actually uses the reflected signals to increase the range and reduce “dead spots” 3
Antenna Basics It was always very hard to introduce antenna techniques until iPhone 4 was released…
Introduction to Antennas An antenna is an electrical conductor or system of conductors Transmission - radiates electromagnetic energy into space (convert the energy into EM waves) Reception - collects electromagnetic energy from space The physical size of the radiating element is proportional to the wavelength The higher the frequency, the shorter the wavelength, and thus, the smaller the antenna size 5
Introduction to Antennas (Cont’d) In two-way communications, the same antenna can be used for transmission and reception But not necessary: e.g., cellular base stations

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