MIMO WIRELESS COMMUNICATION

SYSTEMS

Bhaskar D. Rao

University of California, San DiegoLa Jolla, CA 92093-0407

Textbooks Introduction to Space-Time Wireless

Communications, A. Paulraj, R. Nabar and D. Gore, Cambridge University Press

Fundamentals of Wireless Communications, D. Tse and P. Vishwanath

Space-Time Block Coding for Wireless Communications, E. G. Larsson and P. Stoica

MIMO Wireless Communications, Edited by E. Biglieri, R. Calderbank ….

Prerequistive Classes Digital Communication (ECE 258A,B) Channel Coding (ECE 259A,B) Information Theory (ECE 255A) Statistical Signal Processing (ECE

251A) Array Processing (ECE 251D) Estimation Theory (ECE 275A,B)

Prerequisites

Course Grading Homeworks 40%

Theory and Matlab Project 25%

Presentation on day of Finals Exam 35%

Wireless Channel Characteristics Fading: Multiple Paths with different phases add

up at the receiver resulting in a random path gain ISI: Paths with different delays causing

intersymbol interference (Frequency Selective Channels)

CCI: Co-Channel users create interference Noise: Thermal noise from electronics Doppler: Channel varies over time (mobility) Bandwidth: Bandwidth limited and so data

rates can grow only as log(1 + SNR)

Space-Time Processing for Wireless Communications

Base station Base station

Mobile

Mobile

Mobile

Mobile

Mobile

Goal: Exploit the spatial dimension to improve capacity and

quality of network

Variants of Multiple Antenna Systems

Terminology

Benefits of Space-Time Processing

Increased Capacity Improved Signal Quality Increased Coverage Lower Power Consumption Higher Data Rates

These requirements are often conflicting. Need balancing to maximize system performance

Technical Rationale Spatial Diversity to Combat Fading Spatial Signature for Interference Suppr

ession Array Gain enables Lower Power Consu

mption Multiple Transmit Antennas provide

Transmit Diversity Capacity Improvements using Spatial M

ultiplexing

Scenarios

Base Station or Mobile Receive versus Transmit Antennas MIMO systems Choice of Multiple Access Scheme

(CDMA or TDMA) Microcell versus Macrocell Mobility versus Fixed

Beamforming

Antenna Array

Interferer

Interferer

Interferer

DesiredUser

Multi-Input Multi-Output System

Capacity of MIMO systems

Role of Diversity

Two Fading Channels combined to improve SNR: Diversity gain

Spatial Diversity to Combat Fading