![Page 1: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/1.jpg)
Day 8
Multiplexing
![Page 2: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/2.jpg)
More than 1 signal per cable• Typically a single cable can carry a
single connection– Not good if you want a cable to be
able to send lots of separate• Telephone calls• TV channels• Data connections
![Page 3: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/3.jpg)
Multiple ways to slice things• By Frequency
– Frequency Division Multiplexing
• By time– Synchronous Time Division
Multiplexing – Statistical Time Division Multiplexing
• Other special application– Wavelength Division Multiplexing– Discrete Multitone– Code Division Multiplexing
![Page 4: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/4.jpg)
Frequency Division Multiplexing• Examples
– FM Radio– TV/Cable TV– D-AMPS (old cellular) – 802.11b/g (3 channels)
![Page 5: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/5.jpg)
Frequency Division Multiplexing
![Page 6: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/6.jpg)
Guard Bands• Used to prevent “cross talk”
between the channels.• Empty frequencies between
channels.
![Page 7: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/7.jpg)
Synchronous time division• Each station gets a chance to talk.
– If a station has anything to say, their data is inserted into their block.
– If nothing to say, the block is left empty
– Everyone gets equal time.
![Page 8: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/8.jpg)
Synchronous Time Division Multiplexing
![Page 9: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/9.jpg)
T1/DS1 – 1.544Mb/s• The T1 is a high speed data line
designed to interconnect phone switches.– Also available to end users to provide high
speed data or lots of phone lines
• It uses synchronous time division multiplexing
• 24 Channels – Each frame gets 1 byte from each of 24
devices– 8000 frames per second are transmitted– 56k/channel for voice, 64k for data.
• Extra control bit is used giving 7 bits which is all that is necessary for voice.
• ~$400/month + install
![Page 10: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/10.jpg)
ISDN• 2 B channels (64k)• 1 D channel (16k)• Signal
– Control bits– 8 bits from B1– Control bits– D bit– Control bits– 8 bits from B2
![Page 11: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/11.jpg)
SONET• Synchronous Optical Network
– Single clock• Atomic clock
– Synchronous Transport Signals• OC 1 – 51.84Mbps
– 8000 frames/second 6480 bits/frame• OC 3 = 3*OC1 = 155.52Mbps
– ~ $40k/month• OC48 = 2.5Gbps
– ~$80k/month• OC192 = 192 OC1 =~ 10Gbps
– ~$1/4million per month• 1, 3, 9, 12, 18, 24, 36, 48, 96, 192
• Gige ~$15k/month
![Page 12: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/12.jpg)
Statistical Time Division• Not everyone has something to
say at all times.– Why not give the traffic to those who
do
• If so, we need to add addresses so we know who said what.
• Multiplexer must be smart
![Page 13: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/13.jpg)
Size of frames• Either they must be set in stone• Or you must transmit the size so
the other side can tell where one frame ends and the next starts
![Page 14: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/14.jpg)
Wavelength Division Multiplexing• Using laser color to differentiate
streams• You can now multiplex multiple
OC192’s together on a single cable.– Has been used to create up to
1.6Tbps over a single fiber pair
![Page 15: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/15.jpg)
Discrete Multitone Multiplexing• Examples
– DSL– Digital FM Radio– 802.11a/g
• A specific example of frequency division multiplexing– Data in a particular channel is
transmitted on multiple different frequencies at once.
– Frequencies are chosen to avoid interference with other data
![Page 16: Day 8 Multiplexing. More than 1 signal per cable Typically a single cable can carry a single connection –Not good if you want a cable to be able to send](https://reader035.vdocuments.site/reader035/viewer/2022081603/5697bf891a28abf838c8a2fc/html5/thumbnails/16.jpg)
Code Division Multiplexing• Each user has a code:
– A: 10111001– B: 01101110– C: 11001101
• If you want to send a 1 you send your code, if you want to send a 0 you send the inverse of your code (flip all 0’s and 1’s)
• Receiver gets the sum of all this, adds each code (1= 1 or 0= -1).– +8 means they sent a 1, -8 means
they sent 0