MULTIMEDIA SYSTEMSIREK DEFEE
SIGNAL MODULATIONfor
MULTIMEDIA DATA TRANSMISSION
with special emphasis on wireless
MULTIMEDIA SYSTEMSIREK DEFEE
• Content:
- SIGNAL MODULATION TECHNIQUES
- RADIO WAVE PROPAGATION
- WIRELESS SYSTEMS
- WIRELESS DATA TRANSPORT
- SOURCE AND CHANNEL CODING
(WHICH WE ARE NOT COVERING)
MULTIMEDIA SYSTEMSIREK DEFEE
SIGNAL MODULATION TECHNIQUES:
HOW TO OVERLAY BITS OR STREAMS OF
BITS ON A SIGNAL TO CARRY THEM?
FOR MULTIMEDIA TRANSMISSION WE
NEED TO TRANSFER A LOT OF DATA
THUS, WE NEED TO PACK THE DATA
EFFICIENTLY ON TRANSMISSION
CARRIER ( WHICH CAN BE RADIO WAVES,
ELECTRIC CURRENT, PHOTONS)
MULTIMEDIA SYSTEMSIREK DEFEE
Let’s start from the beginning:Sinusoidal Waveform
• The signal at frequency around fc:
s(t) = Acos(2fct + )• To encode digital symbol of {0, 1},
– One can encode using the amplitude A– One can encode using the phase – One can encode using the frequency fc
– Use some combination of amplitude, phase, or frequency.
MULTIMEDIA SYSTEMSIREK DEFEE
Let’s start from the beginning:Sinusoidal Waveform
• The signal at frequency around fc:
s(t) = Acos(2fct + )• To encode digital symbol of {0, 1},
– One can encode using the amplitude A– One can encode using the phase – One can encode using the frequency fc
– Use some combination of amplitude, phase, or frequency.
MULTIMEDIA SYSTEMSIREK DEFEE
Amplitude-Shift Keying (ASK)Change amplitude A
CARRIER
MULTIMEDIA SYSTEMSIREK DEFEE
ASK (cont.)
• The signal is
0
0)2cos(2
2
1
ts
TttfT
Ets bc
b
b
MULTIMEDIA SYSTEMSIREK DEFEE
Phase-shift Keying (PSK)Change phase
MULTIMEDIA SYSTEMSIREK DEFEE
PSK (cont.)
• Signal is
bcb
b
bcb
b
TttfT
Ets
TttfT
Ets
0)2cos(2
0)2cos(2
2
1
MULTIMEDIA SYSTEMSIREK DEFEE
Frequency-shift keying (FSK)
MULTIMEDIA SYSTEMSIREK DEFEE
FSK (cont.)
• Signal is
bb
b
bb
b
TttfT
Ets
TttfT
Ets
0)2cos(2
0)2cos(2
22
11
MULTIMEDIA SYSTEMSIREK DEFEE
FIGURE 1/V.29
Signal space diagram at 9600 bit/s
HOW TO PUT MORE BITS ON THE CARRIER?1. BY USING MORE PHASE SHIFTS E.G. 8-PSK
HERE WE USE8 PHASEVALUESEACH VALUEENCODES3 BITS
MULTIMEDIA SYSTEMSIREK DEFEE
90°
180° 0°
270°
A
B
D
C
(Re)
(Im)
–4 –2 2 4
2
4
–2
–411100 11011
01110 00001 01100
10110100011011110000
00111 01001 00110 01011 00100
11101110101111011001
00000 01111 00010 01101 00011
10100100111010110010
01000 00101 01010
1100011111
T1702150-93/d03
FIGURE 3/V.32
32-point signal structure with trellis coding for 9600 bit/sand states A B C and D used at 4800 bit/s and for training
NOTE – The binary numbers denote Y0 Y1 Y2 Q3 Q4 .n n n n n
2. BY USING MORE AMPLITUDE LEVELSAND PHASE SHIFTS – EXAMPLE 16-QAM
HERE EACHPHASE/AMPLITUDEVALUE ENCODES 5 BITS
MULTIMEDIA SYSTEMSIREK DEFEE
0 0 0 0 1 1 1
0 0 1 1 1 1 1
0 0 0 0 1 1 0
0 0 1 1 1 1 0
0 0 0 1 1 1 0
0 0 1 0 1 1 0
0 0 0 1 1 1 1
8
6
4
2
-2
-4
-6
-8
0 1 0 1 0 0 0 0 1 0 0 0 0 02 7 0 °
1 1 0 0 0 0 1 1 1 1 1 0 0 0 1 1 0 1 0 0 1 1 1 1 0 0 0 0
0 0 0 0 1 0 1 0 1 1 0 0 0 1 0 1 1 1 0 0 1 0 0 0 0 0 1 1
1 0 1 0 1 0 1 1 0 0 1 0 1 1 1 0 1 0 1 1 1 1 0 0 1 1 1 1 1 0 0 1 1 0 1
0 1 0 1 1 0 1 0 0 1 1 0 1 1 0 1 0 1 1 0 0 0 1 0 0 1 0 0 0 0 1 1 1 0 1 0 1 0 0 1 0 1
1 1 1 0 1 0 11 1 0 1 0 1 11 1 1 0 1 0 01 1 0 1 0 1 01 1 1 1 1 0 01 1 0 0 0 1 01 1 1 1 1 0 11 1 0 0 0 1 1
0 0 0 0 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 0 0 0 1 1 0 0 1 0 0 1 1 1 0 1 0 0 0 0 0 0 1 0 0 1 1 1 0 1 1 0 0 0 0 0 0 1
1 0 0 1 0 0 01 0 1 0 0 0 11 0 0 1 1 0 01 0 1 0 0 1 01 0 0 1 1 1 01 0 1 0 1 1 01 0 0 1 0 1 01 0 1 0 1 0 01 0 0 1 0 0 11 0 1 0 0 0 0
0 0 1 1 0 0 1 0 0 1 1 0 1 0 0 1 0 1 1 1 0 0 1 0 0 1 1 0 0 0 1 1 1 0 0 0 1 0 0 1 1 1 0 0 1 1 0 0 0
1 1 1 0 1 1 11 1 1 0 1 1 01 1 0 1 1 1 01 1 1 1 1 1 01 1 0 0 1 1 01 1 1 1 1 1 11 1 0 0 1 1 11 8 0 °
-6-8 -4 -2 2 4 6 8
0 °
1 0 0 0 0 0 01 0 1 1 0 0 1
0 1 1 1 1 1 10 0 0 1 0 1 00 1 1 1 1 1 00 1 1 0 1 1 00 0 0 1 1 0 00 1 1 0 1 1 10 0 0 1 0 0 0
1 0 1 1 0 0 0 1 0 0 0 0 0 1 1 0 1 1 1 0 0 1 0 0 0 0 1 0 1 0 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 1 0 1 0 1 0 0 0 1 0 0
0 0 1 0 0 0 00 1 0 0 0 1 10 0 1 0 1 0 00 1 0 1 0 1 00 1 0 1 0 1 10 0 1 0 0 0 1 0 0 1 0 0 1 0
1 1 0 0 1 0 1 1 1 1 1 0 1 1 1 1 1 1 0 1 0 1 1 0 1 1 0 0
0 1 0 0 0 1 0
1 1 1 0 0 1 0 1 1 0 1 1 0 1
0 1 1 1 1 0 10 0 0 1 0 1 10 1 1 1 1 0 00 1 1 0 1 0 00 0 0 1 1 0 1
1 0 1 1 1 0 1 1 0 0 0 0 1 1 1 0 1 1 1 1 1 1 0 0 0 1 1 1 1 0 1 1 0 1 1 1 0 0 0 1 0 1
0 0 1 0 1 0 10 1 0 0 0 0 10 0 1 0 1 1 10 1 0 1 0 0 10 0 1 0 0 1 1
1 1 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0 1 0 0 0 1 1 1 0 0 0 1
0 1 1 1 0 0 00 1 1 0 0 0 09 0 °
C
D
A
B
1 1 1 0 0 1 11 1 0 0 1 0 0
0 1 0 1 1 1 1
1 1 0 1 1 1 1
0 0 0 1 0 0 1
0 1 1 0 1 0 1
1 0 1 0 0 1 1
(Im )
(Re)
T1701310-90
n n n n n n n
F IG U R E 2 -1 /V .32 b is
N o te – B ina ry nu m bers refer to Y 0 , Y 1 , Y 2 , Q 3 , Q 4 , Q 5 , Q 6 .A , B , C , D refe r to syn ch ro n iz ing signal e lem en ts .
S ig n a l sp a ce d iagram an d m a p p in g for m od u la t io n a t 14 4 00 b it/s p er secon d
128-QAM EXAMPLE -COMBINATION OF AMPLITUDEAND PHASE ENCODES SPECIFIC BIT PATTERN
MULTIMEDIA SYSTEMSIREK DEFEE
392 330 274 222 177 135 102 77 55 41 35 31 37 48 65 91 118 155 198 248 303 361
380 316 255 203 158 119 84 60 39 24 17 15 20 30 49 72 101 138 182 230 283 348 415
384 324 277 229 189 156 96 87 83 92 172 208 254 299 354
355 294 243 201 160 98 79 64 58 62 71 90 180 221 271 323 387
406 350 306 266 234 253 288 327 379
360 310 263 165 242 289 338 391
412 371 340 353 390
401 357 318 298 337 378
398
408 396 394 400 414
375 349 339 329 326 335 347 359 386
314 290 279 269 265 273 281 302 322
282 257 236 224 216 212 218 228 247 270
206 185 173 164 162 170 181 197 220
146 133 123 121 125 137 154 179 207193226
131 110 100 117 140
126 112 14154
367 304 244 194 148 108 75 50 28 13 6 4 8 21 38 63 93 127 171 219 275 336 402
362 296 238 186 142 103 69 43 22 1 0 5 16 32 56 85 122 163 213 267 328 3959
365 300 240 190 144 106 73 45 25 3 2 7 18 36 59 88 124 166 217 272 331 39711
372 307 251 199 152 113 80 52 33 19 12 10 14 26 42 66 134 174 225 280 341 40997
388 320 261 210 167 128 67 47 34 27 23 29 40 57 81 111 147 187 237 291 35194
410 343 284 232 183 149 89 68 53 46 44 51 61 78 99 132 168 209 258 315 376115
369 311 259 214 175 95 82 74 76 86 157 195 235 285 342 399139 116 104 12970
403 345 292 249 205 191 227 268 319 373176 150 136 161130 114 107 105 109 120
382 332 287 250 231 264 308 358 413215 184 178 202169 153 145 143 151 159
377 333 293 278 312 352 404260 233 223 245211 200 192 188 196 204
383 346 325 363 407313 286 276 295262 252 241 239 246 256
405 385370 344 334 356321 309 301 297 305 317
411 393389 374 366 364 368 381
–11
–15
–19
–23
–27
–31
–35
–39
–43
9
5
1
–3
–7
45
41
37
13
17
21
25
29
33
–43 –39 –35 –31 –27 –23 –19 –15 –11 –7 –3 1 5 9 45413713 17 21 25 29 33
T1403000-97/d05
Figure 5/V.34 – One-quarter of the points in the superconstellation
EXAMPLE OF NUMBERS ENCODING BYSPECIFIC BIT PATTERNS
Thesevalues of signal are encoded by specificmodulation patternson the previouspage
MULTIMEDIA SYSTEMSIREK DEFEE
• The more bits we put the better signal to
noise must be (small phase and amplitude
values are lost in noise)
How to put even more bits on a signal?
By using multicarrier modulation –
bits are overlayed on many carriers at the
same time.
MULTIMEDIA SYSTEMSIREK DEFEE
• ONE USES MANY CHANNELS. EACH CHANNEL IS MODULATED E.G. WITH 8 KBITS/S. WITH MANY CHANNELS
OVERALL DATA RATE GROWS
• EACH CHANNEL CAN BE INDIVIDUALLY TUNED TO THE
TRANSMISSION BANDWIDTH, E.G.
SOME CHANNELS CAN BE SKIPPED
COMPLETELY.
Now we have many carriers
MULTIMEDIA SYSTEMSIREK DEFEE
s1 (t) = Acos(2f1ct + )
s3 (t) = Acos(2f3ct + )s2 (t) = Acos(2f2ct + )
sn (t) = Acos(2fnct + )………………………
The carriers are assumed to be close to each otherf1c fnc……………..
f
A
How the overall modulated signal will look ?
In time domain In frequency domain
signals overlap they also overlap
Example of four subcarriers Spectra of individual subcarriers
We have to add additional condition for signals in order to be able to separate them
• This condition is orthogonality
MULTIMEDIA SYSTEMSIREK DEFEE
* 1 ,
0 , i j
i jx t x t dt
i j
* 1 ,
0 , i j
i jX f X f df
i j
In time domain In frequency domain
The carriers must satisfy these special conditionsThen by summing and adding upp it will be possibleto separate themThis principle is called OFDM, ORTHOGONALFREQUENCY DIVISION MULTIPLEX
MULTIMEDIA SYSTEMSIREK DEFEE
• WHERE ARE THESE SIGNAL
MODULATION TECHNIQUES APPLIED?1. PSK, QPSK – GOOD FOR WEAK SIGNALS,
APPLIED IN THE GSM MOBILE SYSTEM, ALSO IN DIGITAL TELEVISION FROM SATELLITES
2. QAM – REQUIRES STRONGER SIGNALS, APPLIED IN DIGITAL CABLE TELEVISION
AND IN THE EXTENSION OF GSM CALLED EDGE
3. MULTICARRIER OFDM – APPLIED IN TERRESTRIAL DIGITAL TELEVISION, IN WIRELESS LAN, AND IN NEW 4G MOBILE NETWORK VERY EFFICIENT USE OF BANDWIDTH, CAN BE ADJUSTED FOR BAD SIGNAL PROPAGATION
MULTIMEDIA SYSTEMSIREK DEFEE
The OFDM modulation
• It uses radio bands very effectively• Applications in wireless networks
Digital Terrestrial Television: e.g. 8 000, 32 000
Digital Mobile Television 4 000and 8 000 carriers
Wireless LAN (802.11a/g): 52 carriers
Ultra Wide Band: many carriers in many bands
NEW 4th generation mobile system called LTE (Long Term Evolution)- thousands of carriers
MULTIMEDIA SYSTEMSIREK DEFEE
The OFDM modulation cntd.• Applications in wired networks
ADSL – broadband networking over telephone lines
It seems OFDM is the winning signal modulation
technology for multimedia data transmission:- it allows high data bandwidth and is robust against
signal loss
- it is complicated but this is not a problem with current hardware and computer technology
c@Irek Defée MULTIMEDIA SYSTEMS
EXAMPLE OF APPLICATION OF OFDM :
ADSL SYSTEM
BROADBAND NETWORKING
For the home
c@Irek Defée MULTIMEDIA SYSTEMS
• NETWORKING FOR HOME HAS TO BE CHEAP AND DISTRIBUTED ON LARGE SCALE• HOW TO MAKE IT? - LAYING NEW CABLES – NOT
ECONOMICAL (MAYBE IN NEW BUILDINGS)
- WIRELESS – BROADBAND NOT POSSIBLE (MAYBE IN THE FUTURE??)
c@Irek Defée MULTIMEDIA SYSTEMS
• THE ONLY REALISTIC POSSIBILITY
IS TO USE EXISTING CABLING
THERE ARE TWO TYPES OF EXTERNAL
CABLES FOR CARRYING INFORMATION
AVAILABLE IN HOMES:
TELEPHONE (ALMOST EVERYWHERE)
CABLE TV (IN MANY PLACES)
c@Irek Defée MULTIMEDIA SYSTEMS
• TELEPHONE NETWORK IS DESIGNED AS NARROWBAND, CABLES ARE FOR
SPEECH, 4kHz BAND
BUT EVERYBODY HAS SEPARATE LINE
• CABLE TV IS DESIGNED AS BROADBAND BUT ALL USERS SHARE
THE SAME CABLE (FOR TV SIGNAL)
IT LOOKS IMPOSSIBLE TO USE THEM
c@Irek Defée MULTIMEDIA SYSTEMS
• WITH THE OFDM TECHNOLOGY THIS
CAN CHANGE. TELEPHONE CABLE
IS NARROWBAND BUT ITS BANDWIDTH IS NOT 4 kHz.
Bandwidth of typical telephone cable:
4kHz 1MHzABOVE THE 4kHz CABLE BANDWIDTH IS VERY VARIABLE. IT IS DIFFERENT FOR EACH CABLE AND DEPENDS ON DISTANCE
c@Irek Defée MULTIMEDIA SYSTEMS
• UNTIL RECENTLY UNEQUALIZED BANDWIDTH WAS NOT USEFUL,
TOO MUCH SIGNAL DEGRADATION
• NEW SIGNAL PROCESSING TECHNIQUES ENABLE ITS USE
c@Irek Defée MULTIMEDIA SYSTEMS
ADSL
ASYMMETRIC DIGITAL SUBSCRIBER LOOP
THE TECHNIQUE FOR USING ”BAD” CABLE
BANDWIDTH BASED ON
OFDM MULTICARRIER SIGNAL MODULATION
c@Irek Defée MULTIMEDIA SYSTEMS
TELEPHONE NETWORK
TELEPHONEEXCHANGE
BROADBAND LINK
LINKS TO CUSTOMERSARE FEW KMLONG, CABLING IS NARROWBAND
DSLAM
MODEM
MODEM
MODEM
ADSL IN
ADSL MODEMS ENABLE TO USE MORE BANDWIDTH
c@Irek Defée MULTIMEDIA SYSTEMS
MULTICARRIER MODULATION IN ADSL
f
4 kHz CARRIER CHANNELS
EACH CHANNEL IS SEPARATELY MODULATED WITH A SIGNAL.
SIGNAL LEVEL OF EACH CHANNEL CAN BEMATCHED TO THE GAIN AT ITS FREQUENCY
VOICE BANDHIGH BAND
c@Irek Defée MULTIMEDIA SYSTEMS
• IN PRACTICAL SYSTEM ONE USES
256 CHANNELS. EACH CHANNEL IS
MODULATED WITH E.G. 32 KBITS/S
IN TOTAL THIS GIVES 8 Mbits/sec !!!• EACH CHANNEL CAN BE INDIVIDUALLY
TUNED TO THE TRANSMISSION SIGNAL
LEVEL, E.G. SOME CHANNELS CAN BE SKIPPED COMPLETELY.
c@Irek Defée MULTIMEDIA SYSTEMS
• COMPLETE SYSTEM
f4 25 160 240 .....................1200 kHz
TEL. UPSTREAM DOWNSTREAM DATA DATA FROM USER TO USER
THE SYSTEM IS ASYMMETRIC, IT SENDS MORE DATA DOWN THE LINE THAN UP (E.G. 256 kbits/s up)BUT FOR HOME USERS THIS IS OK
c@Irek Defée MULTIMEDIA SYSTEMS
• THERE ARE VERY MANY DETAILS IN ADSL STANDARD:- HOW THE CARRIERS ARE MODULATED?
(QAM MODULATION)- HOW THE MODULATION IS REALIZED?
(512-POINT FFT)- HOW THE ERROR CORRECTION IS PERFORMED? (FEC)- HOW THE SIGNALS ARE
SYNCHRONIZED? (PILOT TONE)
c@Irek Defée MULTIMEDIA SYSTEMS
• THESE DETAILS CAN BE FOUND IN THE ADSL STANDARD AND OVERVIEWS ON THE WEB.
• ADSL IS NOW OFFERED COMMERCIALLY ON LARGE SCALE
PRICES (ARE IN THE RANGE OF
FEW TENS OF €/m FOR 1-8 Mb/s BANDWIDTH. THE SYSTEM WORKS VERY RELIABLY.
c@Irek Defée MULTIMEDIA SYSTEMS
• BUT FROM PRACTICE IT IS KNOWN
THAT ADSL HAS A PROBLEM TOO:
- BANDWIDTH OFFERED DEPENDS ON
DISTANCE, CABLE QUALITY AND
MAY VARY WIDELY
c@Irek Defée MULTIMEDIA SYSTEMS
New ADSL standards
• These are ADSL2 and ADSL2+. They
provide improvements by: - using higher signal power- bonding several phone lines- using greater bandwidth comparing to ADSL
(up to 2.2 MHz)- real time channel estimation and adaptation
of bitrate to channel conditions
MULTIMEDIA SYSTEMSIREK DEFEE
ANOTHER EXAMPLE:Proposed Ultra Wide Band Network
• Ultra Wide Band is wireless network
of very short range but with very
high data transfer rate (600 Mb/s to
1000 Mb/s and more)
This network can eliminate e.g. MONITOR
cable. Then mobile device can drive
the monitor directly.
c@Irek Defée MULTIMEDIA SYSTEMS
UWB -Ultra Wideband Communication
• UWB system is proposed for high speed communication between devices, to eliminate cables:
c@Irek Defée MULTIMEDIA SYSTEMS
Where is UWB?Look around the show for various applications…
Disk Backup
Print Files
Camera Downloads
MP3 File Transfers
Movie Transfers
Video Streaming
…and more!
c@Irek Defée MULTIMEDIA SYSTEMS
What Problem Does UWB Solve?
The Customer’s Frustration with Cables:
• Tangle of cables in our Homes and Offices
• Ever increasing file sizes of content to be downloaded and enjoyed by Consumers
• Consumers don’t want to wait long for a file to transfer
• User Models limited by the use of Cables• Customers to-day prefer Wireless
UWB is more than a Cable replacement technology
Create new User Models and product opportunities not possible today with cables
BUT…..MUST Match the Security of cables
MUST be easy to use
UWB is more than a Cable replacement technology
Create new User Models and product opportunities not possible today with cables
BUT…..MUST Match the Security of cables
MUST be easy to use
c@Irek Defée MULTIMEDIA SYSTEMS
The Vision: Creating new User Models and Product opportunities
PersonalWireless Storage/Wallet
Photo & Video ClipDisplay
Photo Printer
SHARE and EXCHANGECreate New User Models not
possible in the Cabled World
Connecting PC, CE and Mobile Segments
Multi Channel Speakers
In Car Media center& video
Share video clipsMusic & Photos
Media Center
c@Irek Defée MULTIMEDIA SYSTEMS
The Model that Consumers Expect
• Compatible and InteroperableCompatible and Interoperable out of the box
• ManyMany suppliers supporting a Common Standard at all levels of the ecosystem
Buy it Plug it in Use it…Easily!
MULTIMEDIA SYSTEMSIREK DEFEE
UWB opportunity
• If Ultra Wide Band networking becomes
popular and monitors/TV’s will
get it, then there will be no need to
connect TV and monitor by cable
to their signal sources. Mobile devices
will display on them directly
MULTIMEDIA SYSTEMSIREK DEFEE
Imagine this
Mobile device has wireless
links to keyboard and display
Bluetooth
UWB
Ultra Wide Band
Mobile devices are more and
more capable (processors,
memory, hard discs), resembling
PC from few years ago
c@Irek Defée MULTIMEDIA SYSTEMS
Principle of UWB
• Ultra wideband system uses very broad
frequency band:
There are UWB standards proposed which are based on several principles: One of them is MULTIBAND OFDMwith many thousands of carriers.
MULTIMEDIA SYSTEMSIREK DEFEE
UWB is Multi-band OFDM
• Central Idea #1: – Divide the spectrum into bands that are 528 MHz wide.
• Advantages:– Transmitter and receiver process smaller bandwidth signals.– Instantaneous processing BW = 528 MHz.
f3432MHz
3960MHz
4488MHz
5016MHz
5544MHz
6072MHz
6600MHz
7128MHz
7656MHz
8184MHz
8712MHz
9240MHz
9768MHz
Band #1
Band #2
Band #3
Band #4
Band #5
Band #6
Band #7
Band #8
Band#9
Band #10
Band #11
Band #12
Band #13
10296MHz
Band #14
Band Group #1 Band Group #2 Band Group #3 Band Group #4 Band Group #5
MULTIMEDIA SYSTEMSIREK DEFEE
Exploiting the Band Plan
• Exploit range of band group’s to separate applications:
Longer Range Apps Use BG #1 and #2
f3432MHz
3960MHz
4488MHz
5016MHz
5544MHz
6072MHz
Band #1
Band #2
Band #3
Band #4
Band #5
Band #6
Band Group #1 Band Group #2
MULTIMEDIA SYSTEMSIREK DEFEE
Exploiting the Band Plan
• Exploit range of band group’s to separate applications:
` Shorter Range Apps Use BG #3 and #4
f3432MHz
3960MHz
4488MHz
5016MHz
5544MHz
6072MHz
6600MHz
7128MHz
7656MHz
8184MHz
8712MHz
9240MHz
9768MHz
Band #7
Band #8
Band#9
Band #10
Band #11
Band #12
10296MHz
Band Group #3 Band Group #4
MULTIMEDIA SYSTEMSIREK DEFEE
Overview of Multi-band OFDM
• Central Idea #2: – Interleave OFDM symbols across all bands.
• Advantages:– Exploits frequency diversity.– Provide robustness against multi-path / interference.– Same transmit power as if the entire band is used.
TimeFreq (MHz)
3168
3696
4752
4224
Band # 1
Band # 2
Band # 3
MULTIMEDIA SYSTEMSIREK DEFEE
• EDGE – ENHANCED DATA RATE FOR
GSM EXPANSION
TECHNIQUE FOR INCREASING THE BIT
RATE OF GSM SYSTEM BY USING
8-PSK.
IT IS ADOPTED FOR DATA TRANSFER
BUT REQUIRES MAJOR HARDWARE
UPGRADES IN THE SYSTEM
IMPORTANT EXAMPLE
MULTIMEDIA SYSTEMSIREK DEFEE
• Ultra Wide Band connections were demonstrated for television sets
• Television sets are
• becoming so thin that that there is no place
• for connectors
• Signal can be
transmitted by wireless UWB link.
CURRENT STATUS OF UWB
c@Irek Defée MULTIMEDIA SYSTEMS
ANOTHER EXAMPLE Home Communication over Powerlines
• Powerlines are everywhere, in every room
at home. There is a question if they could be used
for data transmission. After very long development
it looks that powerline communication will become
available e.g. one can see products from:
www.devolo.com
c@Irek Defée MULTIMEDIA SYSTEMS
• The system is very simple to install:
c@Irek Defée MULTIMEDIA SYSTEMS
• How this system operates?
It is based on a standard called Homeplug. For signal
transmission the band which is used is 2-28 MHz
with OFDM modulation. It has 917 carriers and
carriers can be independently modulated by
different modulations from PSK up to 1024 QAM
The maximum data rate can be up to 150 Mb/s,
practical rates are 40-85 Mb/s.
The standard has a lot of other details:
www.homeplug.org
FURTHER EXAMPLES OF OFDMWIRELESS SYSTEMS
MULTIMEDIA SYSTEMSIREK DEFEE
1. LTE – next generation mobile system2. WiMax – next generation network3. WLAN – local area network
c@Irek Defée MULTIMEDIA SYSTEMS
LTE – Next mobile system after 3G
• LTE = Long Term Evolution
• Extension of 3G network
• Higher databandwith, uses OFDM modulation
• LTE is fully oriented to multimedia and advanced applications -> analyze next slide
c@Irek Defée MULTIMEDIA SYSTEMS
c@Irek Defée MULTIMEDIA SYSTEMS
LTE OFDM• Orthogonal Frequency-Division Multiplexing
• FDM where carriers are appropriately spaced to insure orthogonality. Notice the overlap!!
• Spectrally efficient!!
c@Irek Defée MULTIMEDIA SYSTEMS
OFDM signal in time and frequencyOFDM signal in time and frequency
Fig. Frequency –time representation
Fig. MIMO
Please note that signals on different subcarriers (frequency axis)carry modulation symbols (time axis). Modulation symbols (QPSK or QAM) are separated by short breaks (guard intervals)
c@Irek Defée MULTIMEDIA SYSTEMS
LTE Parameters System to the User– How much data can be sent to the user
– The system is very flaxible, has many parameters
Transmission BW1.25 MHz 2.5 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Sub-frame duration 0.5 ms
Sub-carrier spacing 15 kHz
Sampling frequency 1.92 MHz(1/2 3.84 MHz)
3.84 MHz 7.68 MHz(2 3.84 MHz)
15.36 MHz(4 3.84 MHz)
23.04 MHz(6 3.84 MHz)
30.72 MHz(8 3.84 MHz)
FFT size 128 256 512 1024 1536 2048
Number of occupied sub-carriers†, ††
76 151 301 601 901 1201
Number of OFDM symbols
per sub frame(Short/Long CP)
7/6
CP length (μs/samples)
Short (4.69/9) 6,(5.21/10) 1*
(4.69/18) 6,(5.21/20) 1
(4.69/36) 6,(5.21/40) 1
(4.69/72) 6,(5.21/80) 1
(4.69/108) 6,
(5.21/120) 1
(4.69/144) 6,(5.21/160) 1
Long (16.67/32) (16.67/64) (16.67/128) (16.67/256) (16.67/384) (16.67/512)
c@Irek Defée MULTIMEDIA SYSTEMS
How much data teh user can sentTransmission BW 1.25
MHz2.5 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Timeslot duration 0.675 ms
Sub-carrier spacing 15 kHz
Sampling frequency 1.92 MHz
(1/2 3.84 MHz)
3.84 MHz 7.68 MHz(2 3.84 MHz)
15.36 MHz
(4 3.84 MHz)
23.04 MHz
(6 3.84 MHz)
30.72 MHz
(8 3.84 MHz)
FFT size 128 256 512 1024 1536 2048
Number of occupied sub-carriers†, ††
76 151 301 601 901 1201
Number of OFDM symbols
per Timeslot(Short/Long CP)
9/8
CP length (μs/samples) Short 7.29/14 7.29/28 7.29/56 7.29/112 7.29/168 7.29/224
Long 16.67/32 16.67/64 16.67/128 16.67/256 16.67/384 16.67/512
Timeslot Interval (samples) Short 18 36 72 144 216 288
Long 16 32 64 128 192 256
LTE parameters User to the System
c@Irek Defée MULTIMEDIA SYSTEMS
LTE modulation structure
In the LTE the channel width and number of carriers is flexible 12 carriers form one resource block, 1 slot in time is 0.5 msand it carries 7 OFDM symbols, 1 subframe is 2 slots
LTE DATA TRANSFER CAPACITY
• There are so many parameters in the system
that data transfer can be very flexibly adjusted. One can say that practically several tens of megabits per second is possible. Thus, LTE will be the first wide area wireless network with full multimedia data transfer capabilities
MULTIMEDIA SYSTEMSIREK DEFEE
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax Network
• New type of networks to be deployed in the near future
• Two types specified:
• One type of them is a substitute for ADSL,
with wireless modems – fixed network
• Antoher type is full mobile network
c@Irek Defée MULTIMEDIA SYSTEMS
WiMAX• World Interoperability for Microwave Access
• There are two main applications of WiMAX:
1) Fixed WiMAX (IEEE 802.16-2004) - Fixed WiMAX applications are point-to-multipoint enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL for homes and businesses.
2) Mobile WiMAX (IEEE 802.16e-2005) - Mobile WiMAX offers the full mobility of cellular networks at true broadband speeds.
c@Irek Defée MULTIMEDIA SYSTEMS
WiMAXFixed WiMAX Architecture
c@Irek Defée MULTIMEDIA SYSTEMS
WiMAXMobile WiMAX Architecture
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax Basics
• WiMax allows data transport over multiple broad frequency ranges
• WiMax’s transmission range and data rate vary significantly depending on the frequency bands an implementation uses
• Orthogonal frequency division multiplexing (OFDM)
• 10 to 66 GHz range
• 75 Mbits
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax frequency bands• IEEE 802.16a
Spectrum: 2 to 11GHzMore flexible while maintaining the technology’s data rate and transmission range
• IEEE 802.16b5 and 6 GHz frequencyprovides quality of servicepriority transmission for real-time voice and video and to offer differentiated service levels for different traffic types
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax Technical Specifications
• OFDM modulation with 256 cariers, 192 useful• Mobile WiMax 256 to 1024 carriers• Modulation PSK, QPSK, 16 QAM, 64 QAM
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax Data Rates
• Note: there are several channel bandwidths,
many modulation types and OFDM carriers
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax Technical Specifications
• Up to 280 Mbps per base stations• Base station transmission range up to 50 km• True broadband for portable users - providing
broadband connectivity for laptops and PDAs with integrated WiMax technology
c@Irek Defée MULTIMEDIA SYSTEMS
WiMax radio frequency bands
• 2.3 GHz, 2.5 GHz, 3.4 GHz, 3.6 GHz,
• 5.4 GHz, 5.8 GHz and possibly others
• such as 700 MHz and 900 MHz or even up to 66 GHz
c@Irek Defée MULTIMEDIA SYSTEMS
WLANWIRELESS LOCALAREA NETWORK
c@Irek Defée MULTIMEDIA SYSTEMS
What is Wireless LAN?
c@Irek Defée MULTIMEDIA SYSTEMS
Wireless LAN Solution
• Extends the local area network • Freedom to access the corporate network
- high-speed rates- features comparable to those of wired networks
• Reliable communications in network access areas
- meeting rooms- other corporate offices- airports - hotels - remote and home offices
• Secure access to important information - e-mail- corporate data- the Internet
c@Irek Defée MULTIMEDIA SYSTEMS
Wireless LAN PC CardWireless LAN PC Card • Each wireless station and access point has a wireless LAN card• Provides an interface between an end-user device and radio waves
Wireless LAN Access PointWireless LAN Access Point• Connected to the wired network
• Acts as bridge between wireless and wired network• Enables high-performance network access
Internet
E-mail E-mail
serverserver
WWWWWWserverserver
Radio signalRadio signal
Security solutionSecurity solution
+
FirewallFirewall
How Does Wireless LAN Solution Work?
c@Irek Defée MULTIMEDIA SYSTEMS
THE WIRELESS LAN SOLUTION
COMMON AREASMEETING ROOMS
TRAINING CENTERSTEMPORARY
OFFICES
CORPORATE CAMPUS
AIRPORTS, HOTELSCONVENTION CENTERS
BUSINESS TOWERS
HOT SPOTS
BRANCH OFFICES
CONNECTIVITY TO CORPFACILITIES, ACCESS FOR
ROAD WARRIORS
HOME OFFICE
QUICK CONNECTIONPORTABLE
EASY START-UP
c@Irek Defée MULTIMEDIA SYSTEMS
• THERE ARE FOUR FAMILIES OF
WLAN STANDARDS:
WLAN Standard Over-the-Air (OTA) Estimates (Bitrate of signals transmitted)
Actual rate for data transmission(Data transfer)
802.11b OLD 11 Mbps 5 Mbps
802.11g 54 Mbps 25 Mbps (when .11b is not present)
802.11a 54 Mbps 25 Mbps
802.11n 200+ Mbps 100 Mbps Note: 802.11n is new and not commonly available yet
c@Irek Defée MULTIMEDIA SYSTEMS
• WLAN RADIO BANDS
IEEE 802.11g 2.4 GHz
IEEE 802.11a 5 GHz (200MHz)
IEEE 802.11n 2.4 and 5 GHz
• MODULATION:
- OFDM - (MULTICARRIER
MODULATION) IEEE 802.11a and g
c@Irek Defée MULTIMEDIA SYSTEMS
What is IEEE802.11b WLAN?It is substitute for the Ethernet. All userssend and receive packets in the same band.radio resources are allocated for them onrandomized basis. The more users are on-line, the less bandwidthis available. IEEE 802.11b bandwidth is:11 Mb/s theoretically 5 Mb/s practically – shared by all usersRange: 15-100m (bulidings, open spaces)
c@Irek Defée MULTIMEDIA SYSTEMS
• CHANNEL BANDWIDTH
20 MHz – 52 CARRIER FREQUENCIES 48 USED FOR DATA
QPSK AND QAM MODULATION IS USED FOR CARRIERS GROSS BIT RATES ARE FROM 6-54 Mb/sec USEFUL BIT RATES ABOUT HALF OF
THAT
c@Irek Defée MULTIMEDIA SYSTEMS
• THE SYSTEM DATA TRANSFER IS
ORGANISED AS TIME DIVISION
MULTIPLEX IN FRAMES
EACH FRAME HAS LENGTH OF 2 ms
AND WITHIN IT PACKETS OF DATA
SEND (48 BYTES)
c@Irek Defée MULTIMEDIA SYSTEMS
• PERFORMANCE CAN REACH PRACTICALLY 20 Mb/sec
• THE NUMBER OF USERS:
TRANSMISSION RANGE IS 30-150 M (TRANSMITTER POWER 0.2-1W) THERE ARE MAX. 19 CHANNELS• DEPENDING ON THE BANDWIDTH THERE COULD BE ABOUT 50-70(?) USERS FOR 1 ACCESS POINT
c@Irek Defée MULTIMEDIA SYSTEMS
The 802.11n standard
• This is new standard improving on the older ones
• The major improvements are:
- Better OFDM modulation up to 65 Mb/s
- It can use several transmission and receiving systems and the same time
c@Irek Defée MULTIMEDIA SYSTEMS
Multiple stream transmission in 802.11n
Here there is a scheme with 2 streams, in the 802.11n standard there can be 2,3, or 4 streams, the bit rate will be 2x,3x,4x higher.In the end we can have up to 100 Mb/s data transfer with 4 streams.The standard has also optional modes of operation (with wider channels)The data rate then could be up to 300 Mb/s.
Digital Terrestrial and Mobile Television
• There are 3 standards: DVB-T, DVB-T2 and DVB-H
• OFDM modulation is used with 2000, 4000, 8000…. up to 32 000 carriers
• Each carrier can be modulated with PSK, 16-QAM, 64-QAM up to 256-QAM
• Data rates are between 20-40 Mbits/sec in single TV
channel with 8 MHz width
Digital Television is widely used in Europe
MULTIMEDIA SYSTEMS
IREK DEFEE
Top Related