mobile communications ecs 455 - prapun.phath.amprapun.phath.am/ecs455 452 and senior projects -...
TRANSCRIPT
Asst. Prof. Dr. Prapun Suksompong
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EC Talk
Office Hours: (BKD 3601-7)
Wednesday 9:30-11:30
Wednesday 16:00-17:00
Thursday 14:40-16:00
Outline
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Courses
ECS 452: Digital Communication Systems
ECS 455: Mobile Communications
ECS 456, 477
Senior projects
Courses: General Information
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Annotated lecture notes and slides from previous years are available at prapun.com http://www2.siit.tu.ac.th/prapun/ecs455/ http://www2.siit.tu.ac.th/prapun/ecs452/
Tentative grading policy
No project
Assignments 5%
Class Participation and Quizzes 15%
Midterm Examination 40%
Final Examination 40%
Asst. Prof. Dr. Prapun [email protected]
Course Introduction
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Mobile CommunicationsECS 455
Office Hours: (BKD 3601-7)
Wednesday 9:30-11:30
Wednesday 16:00-17:00
Thursday 14:40-16:00
Marty Cooper: Cellphone Inventor
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1973
Motorola DynaTAC prototype
Weighed nearly two kilos
Cost approximately $1 million for Motorola to produce.
20 minutes battery life
[http://gizmodo.com]Not a problem because you could
not hold it up for twenty
minutes; it was so heavy.
iPhone 5s Teardown
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Qualcomm MDM9615M LTE Modem
Qualcomm WTR1605L
LTE/HSPA+/CDMA2K/TDSCDMA/EDGE/GPS transceiver
iPhone 5s Spec
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Cellular:
GSM
ECS455: Topics
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1. “Wireless” Communications: Problems and Solutions.
2. “Cellular” Communications: Motivation and Analysis.
3. Multiple Access Schemes: How can many users share communication resources?
4. Spread Spectrum Communications including CDMA (2G-3G)
5. OFDM systems (3.5-4G)
6. Communication techniques in GSM, GPRS, EDGE, UMTS (W-CDMA), WiMAX (OFDMA), LTE (SC-FDMA)
Asst. Prof. Dr. Prapun [email protected]
Course Introduction
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Digital Communication Systems
ECS 452
Office Hours: (BKD 3601-7)
Wednesday 9:30-11:30
Wednesday 16:00-17:00
Thursday 14:40-16:00
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“The fundamental problem of
communication is that of
reproducing at one point
either exactly or approximately a
message selected at another point.”
Shannon, Claude.
A Mathematical Theory Of
Communication. (1948)
Basic elements of communication
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Noise Source
ReceiverTransmitterInformation
SourceDestinationChannel
Received
SignalTransmitted
SignalMessage Message
Digital Communication
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Source
Encoder
Channel
Encoder
Channel
Channel
Decoder
Source
Decoder
010100
010100
Bin
ary
Inte
rfac
e
Input
Output
Take the bits from one place to another.
Binary data stream (sequence of data) without
meaning (from channel viewpoint).
This is the major layering of all digital communication systems.
Know the probabilistic
structure of the input
source.
+ noise &
interference
Waveform sequence symbols bits
General Ideas
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Extension of Principles of Communications (ECS332) and
Probability and Random Processes (ECS315)
Focus more on
performance analysis (bit error rates),
optimal receivers, and
limits (information theoretic capacity).
ECS 452 Topics
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Random noise process
Optimal Receivers
Digital modulation techniques and their performance
Source coding and entropy
Information theory (capacity)
Channel coding
Wireless communications
MIMO: Multiple-Input Multiple-Output
OFDM: Orthogonal-Frequency Division Multiplexing
ECS456: Optical Communication
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Prerequisite: ECS233 (Electromagnetics)
Description: Characteristics of lightwave propagation in optical
fibers.
Types of optical fibers.
Optical transmitters and receivers.
Optical filters and amplifiers.
Optical components: optical divider and combiner, coupler, lens switches.
Optical communication systems.
Coding, multiplexing, demultiplexing, switching, and wavelength conversion.
Optical network architectures.
Type: Lecture 80% Project 20%
Note: Good for better job opportunity
ECS477 Signal Processing for
Communication Systems
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Prerequisite: ECS472 (DSP)
Description: Project-Based
Speech coding and decoding
image coding and decoding
filter banks and multi-rate signal
processing
channel estimation/ equalization/
synchronization
array processing and power spectral
estimation
adaptive filtering
Type: Lecture 50% Project 50%
Note: MATLAB programming intensive,
good for graduate study.
Assoc. Prof. Dr. Chalie Charoenlarpnopparut
Asst. Prof. Dr. Prapun Suksompong
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Senior Projects
At a glance
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MATLAB Simulations
Wireless Communications
1. OFDM, MIMO, Multi-User Techniques
2. Visible light communication (VLC)
3. 60 GHz Communication
4. Game theory in wireless and communication networks
5. RFID Localization
WiFi: IEEE 802.11
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802.11: PHY Data Rates
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Wireless Digital Comm. System
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Encoder0100101010001 Decoder
0100101010001
Transmitter (Tx) Receiver (Rx)
Wireless Channel (SISO)
MIMO: 802.11n
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(Multiple Input Multiple Output)
Encoder0100101010001 Decoder
0100101010001
y
zy x H
NoiseChannel Matrix
x
Wireless Channel (MIMO)
MIMO/SDM
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Encoder0100101010001
Decoderyx
Problem: Interference among transmitting antennas
Solution: Pre-process (pre-code) the transmitted signals
Advantage: Space-division multiplexing (SDM)Transmit multiple independent data streams or
spatial streams on different antennas
1110101010101
0000101111000
0100101010001
1110101010101
0000101111000
(SU-MIMO)
802.11agn: 54 Mb/s to 600 Mb/s
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802.11ac PHY Data Rates
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Multiple Users: Downlink MU-MIMO
26 4(2,2) System
STA1
STA2
Encoder
Encoder
0100101010001
0100101010001
0100101010001
0100101010001
x
1s
2s
1y
2y
2 2
1
2
1 1zy x
y zx
H
H
To: STA1
To: STA2
(in the bedroom)
(in the living room)
At a glance
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MATLAB Simulations
Wireless Communications
1. OFDM, MIMO, Multi-User Techniques
2. Visible light communication (VLC)
3. 60 GHz Communication
4. Game theory in wireless and communication networks
5. RFID Localization
Radio-frequency spectrum
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Commercially exploited bands
c f
Wavelength
Frequency
83 10 m/s
[http://www.britannica.com/EBchecked/topic-art/585825/3697/Commercially-exploited-bands-of-the-radio-frequency-spectrum]
Note that the freq. bands are
given in decades; the VHF band
has 10 times as much frequency
space as the HF band.
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Thailand Freq. Allocations Chart
30http://www.ntc.or.th/uploadfiles/freq_chart_thai.htm
Thailand 2.1GHz Auction
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4.5bn baht per license (freq chunk)
1 license (chunk) = 5 MHz (UL) + 5 MHz (DL)
450 million baht per MHz
30 million baht per MHz per year
Limitations/constraints of RF
Communications
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Radio wave resource
Limited (bandwidth), Scarce, Expensive, Regulated
Capacity: We are simply running out of spectrum.
Can’t keep up with the demand of wireless data transmissions
Interference with other products/systems
Have to switch off your mobile phone during flights.
Mobile phones and WiFi’s are undesirable in certain parts of hospitals, especially around MRI scanners and in operating rooms.
Security
Radio waves penetrate through walls. They can be intercepted.
And God said, ְיִהי אֹור
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VLC and LEDs
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Visible Light Spectrum (VLC)
Widespread deployment of Light-Emitting Diodes (LEDs) for energy conservation in general lighting.
Substitute of conventional incandescent and fluorescent lamp due to its lower power consumption, high efficiency and longer lifetime.
Information can be modulated (at high-speed) into the instantaneous optical intensity. Provide a data channel in addition to the illumination, which is
provided by the average signal level. Convergence of illumination and communications.
VLC is now regarded as one of the most important green communication technologies.
VLC: Advantages
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Huge bandwidth
10,000 times larger than the radio waves spectrum.
Unregulated, license-free operation. No licensing fees.
High communication security. Easy to block.
No interference with sensitive electronic systems.
Safe
Light has been around for many millions of years. It has created us, has created life, has created all the stuff of life.
So it's inherently safe to use.
Availability: the existing lighting infrastructure can be used
Billions of light bulbs already installed.
Low-cost front-end devices
Possible Applications
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Possible Applications
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At a glance
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MATLAB Simulations
Wireless Communications
1. OFDM, MIMO, Multi-User Techniques
2. Visible light communication (VLC)
3. 60 GHz Communication
4. Game theory in wireless and communication networks
5. RFID Localization
60 GHz Wireless Communications
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Millimeter-wave (mm-wave) technology
Unlicensed band
One of the largest being allocated
At least 5 GHz of continuous bandwidth worldwide
Small form factor
Can be conveniently integrated into consumer electronic products.
Huge path loss
Enables higher-frequency reuse in each indoor environment.
Cognitive radios: Motivation
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Back to radio-frequency spectrum
Traditional Rule: Allow predetermined licensed users the right to transmit at given frequencies. Frequency bands were sold at auction, bringing considerable revenue
to the government. Unlicensed users are regarded as “harmful interference.”
Radio-frequency resources are not fully utilized There exists a large number of frequency bands that have
considerable, and sometimes periodic, idle time intervals. For example, some TV stations do not work at night. Spectrum holes.
Cognitive radios
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A revolutionary communication paradigm that can utilize the
existing wireless spectrum resources more efficiently.
New Assumption: Users are intelligent and have the ability to
observe, learn, and act to optimize their performance.
Game theory has been recognized as an important tool in
studying, modeling, and analyzing the cognitive interaction
process.
Game Theory
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A branch of applied mathematics as well as of applied sciences.
A formal framework with a set of mathematical tools
To
study the complex interactions
analyze competition and cooperation
among interdependent rational players (having individual self-
interests.)
For more than half a century, game theory has led to revolutionary
changes in economics.
Three Nobel Prizes have been given in the economic sciences for
work primarily in game theory.
RFID Positioning and Localization
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RFID = Radio Frequency
Identification
Want to link identification
information to location
The strength (and its changes) of
RF signals could be utilized to
locate and hence track objects.