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ECEN5553 Telecom SystemsDr. George ScheetsWeek #13[28a] "What to Expect from 11ac’s Next Big Deal"[28b] "Old-School Wi-Fi is Slowing Down Networks"[28c] "Inside the IT Challenges of Sports and Entertainment"[29a] "Fantastic 4G"[29b] "A Surge in Small Cells"[30] "Riding the Data Tsunami in the Cloud"Exam #2 Results (90 points max)
Hi = 86.9, Low = 42.0, Average = 70.01, Deviation = 14.81A > 81, B > 66, C > 57, D > 48
Term PaperTerm Paper14 November – Remote DL14 November – Remote DLLate Fee = -1 point per working dayLate Fee = -1 point per working day
Final ExamFinal ExamLive: 10:00 – 11:50 AM, Monday, 8 DecemberLive: 10:00 – 11:50 AM, Monday, 8 DecemberDL: Not Later than Monday, 15 DecemberDL: Not Later than Monday, 15 December
ECEN5553 Telecom SystemsDr. George ScheetsWeek #13[28a] "What to Expect from 11ac’s Next Big Deal"[28b] "Old-School Wi-Fi is Slowing Down Networks"[28c] "Inside the IT Challenges of Sports and Entertainment"[29a] "Fantastic 4G"[29b] "A Surge in Small Cells"[30] "Riding the Data Tsunami in the Cloud"Exam #2 Results (90 points max)
Hi = 86.9, Low = 42.0, Average = 70.01, Deviation = 14.81A > 81, B > 66, C > 57, D > 48
Term PaperTerm Paper14 November – Remote DL14 November – Remote DLLate Fee = -1 point per working dayLate Fee = -1 point per working day
Final ExamFinal ExamLive: 10:00 – 11:50 AM, Monday, 8 DecemberLive: 10:00 – 11:50 AM, Monday, 8 DecemberDL: Not Later than Monday, 15 DecemberDL: Not Later than Monday, 15 December
Final ExamFinal Exam
Work 5 of 7 pagesWork 5 of 7 pages 2 - 3 pages will be from the Fall '13 final2 - 3 pages will be from the Fall '13 final 85-90% Notes85-90% Notes
10-15% Readings10-15% Readings Use the space provided!Use the space provided!
# Facts should be # Facts should be >> number of points number of pointsetc.etc.
Start Reviewing Now!
Syllabus Grade Break PointsSyllabus Grade Break Points A A >> 410 points (90%) 410 points (90%) B B >> 364 points (80%) 364 points (80%) C C >> 319 points (70%) 319 points (70%) D D >> 273 points (60%) 273 points (60%)
>> 410 points? Guaranteed an A 410 points? Guaranteed an A >> 364 but < 410? Guaranteed a B, etc. 364 but < 410? Guaranteed a B, etc. Otherwise, at mercy of CourtOtherwise, at mercy of Court
Fall 2013 Break PointsFall 2013 Break Points A A >> 387 points (85%) 387 points (85%) B B >> 341 points (75%) 341 points (75%) C C >> 296 points (65%) 296 points (65%) D D >> 250 points (55%) 250 points (55%)
Fall 2014 points likely not the same.Fall 2014 points likely not the same. Probably in same vicinityProbably in same vicinity Won't know for sure until everything's gradedWon't know for sure until everything's graded
Satcom & Flat Panel Antenna ArraysSatcom & Flat Panel Antenna Arrays
USS Lake Champlain: Aegis Guided Missile Cruiserimage source: wikipedia
Bit Error Rate Unsatisfactory?Bit Error Rate Unsatisfactory?
System designer has several options:System designer has several options: Use FEC codesUse FEC codes Increase received signal powerIncrease received signal power
Crank up transmitter power outCrank up transmitter power out Use directional antennasUse directional antennas
Use more effective modulation techniqueUse more effective modulation technique Slow down the transmitted symbol rateSlow down the transmitted symbol rate Use less noisy receiver electronicsUse less noisy receiver electronics
Voyager II Deep Space ProbeVoyager II Deep Space Probe Used all of previous techniques on downlink:Used all of previous techniques on downlink:
2:1 FEC Coding (different code than in previous examples)2:1 FEC Coding (different code than in previous examples) Increasingly sophisticated earth receive antennasIncreasingly sophisticated earth receive antennas Binary PSK signalingBinary PSK signaling Reduced bit rates Reduced bit rates Cryogenically cooled receiver electronicsCryogenically cooled receiver electronics
Flight historyFlight history LaunchLaunch , August 1977 , August 1977 Jupiter fly-by, July 1979, Message bit rate: 115.2 KbpsJupiter fly-by, July 1979, Message bit rate: 115.2 Kbps Saturn fly-by, August 1981, Message bit rate: 44 KbpsSaturn fly-by, August 1981, Message bit rate: 44 Kbps Uranus fly-by, Uranus fly-by, January 1986, Message bit rate: 29.9 KbpsJanuary 1986, Message bit rate: 29.9 Kbps Neptune fly-by, August 1989, Message bit rate: 21.6 KbpsNeptune fly-by, August 1989, Message bit rate: 21.6 Kbps Now well past Pluto. NASA is still in contact.Now well past Pluto. NASA is still in contact.
Pre-Cellular Mobile Telephony Pre-Cellular Mobile Telephony
source: Telecommunications by Warren Hioki, 1st Edition
0th Generation Mobile Phones0th Generation Mobile Phones
Source: http://www.wb6nvh.com/MTSfiles/Carphone1.htm
Cellular Telephone SystemCellular Telephone Systemso
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Cellular Telephony Advantages:Cellular Telephony Advantages: Frequency Reuse Reduced Transmitter Power Out Reduced Multipath Problems Reduced brain damage? Subdividing Cells increases System
Capacity More Reliable due to cell overlap
Cellular Telephony Disadvantages:Cellular Telephony Disadvantages:
More complexMore complex More installation hasslesMore installation hassles
BS to MTSO link (Backhaul) & switching BS to MTSO link (Backhaul) & switching requirements can get out of hand requirements can get out of hand
Techniques to Increase Bit Rate(Per Channel Basis)
Techniques to Increase Bit Rate(Per Channel Basis)
Use FECUse FEC Increase Received Signal PowerIncrease Received Signal Power Change Modulation TechniqueChange Modulation Technique Build a Quieter ReceiverBuild a Quieter Receiver Slow Down Transmitted Bit RateSlow Down Transmitted Bit Rate Increase Available BandwidthIncrease Available Bandwidth Compress the Application SignalCompress the Application Signal
Increases Increases apparentapparent bit rate bit rate
Seven Smaller CellsSeven Smaller Cells
Set #310 Channels
Set #110 Channels
Set #210 ChannelsCan
Support70 Userswith sameChannelset.
Mobile TrafficMobile Traffic
Source: "The Great Spectrum Famine", IEEE Spectrum Magazine, October 2010.
Cellular Telephony - OperationPower Up & Intermittently ThereafterCellular Telephony - OperationPower Up & Intermittently Thereafter
Mobile tunes to strongest control channelMobile tunes to strongest control channel Mobile communicates with BS/MTSOMobile communicates with BS/MTSO Local MTSO notes in database mobileLocal MTSO notes in database mobile
is active & which cell it's inis active & which cell it's in If mobile is roaming, Home MTSO isIf mobile is roaming, Home MTSO is
notified, typically via SS7 or SIP Signalingnotified, typically via SS7 or SIP Signaling
Cellular Telephony - OperationMobile to Wired callCellular Telephony - OperationMobile to Wired call
Mobile transmits # to BS/MTSOMobile transmits # to BS/MTSO Uses Control ChannelUses Control Channel
Unused voice RF channel is assigned Unused voice RF channel is assigned Mobile tunes to assigned channelsMobile tunes to assigned channels
BS & MTSO coordinate BackhaulBS & MTSO coordinate Backhaul MTSO places call via CO to wired unitMTSO places call via CO to wired unit
Could be via PSTN or VoIPCould be via PSTN or VoIP
Cellular Telephony - Operation Wired to Mobile callCellular Telephony - Operation Wired to Mobile call
Signaling info shipped to home MTSOSignaling info shipped to home MTSO Home MTSO checks databaseHome MTSO checks database
Mobile in home area? Mobile is pagedMobile in home area? Mobile is paged Mobile not in home area? Mobile not in home area?
Signaling info is forwarded to local MTSO Signaling info is forwarded to local MTSO Local MTSO database indicates Mobile's cellLocal MTSO database indicates Mobile's cellMobile is paged & tunes to assigned RF channelMobile is paged & tunes to assigned RF channel
End-to-End Voice channel is set upEnd-to-End Voice channel is set up BS & MTSO coordinate BackhaulBS & MTSO coordinate Backhaul MTSO & CO coordinate Long HaulMTSO & CO coordinate Long Haul
Cellular Telephony - OperationCellular Telephony - Operation HandoffHandoff
MTSO/BS/Mobile decides signal gettingMTSO/BS/Mobile decides signal gettingtoo weaktoo weak
Adjacent cells are polledAdjacent cells are polledUnused voice RF channels in the newUnused voice RF channels in the new
cell is assignedcell is assignedMobile tunes to assigned channelMobile tunes to assigned channelMTSO reroutes traffic: MTSO reroutes traffic:
Old BS Old BS MTSO to New BS MTSO to New BS MTSO MTSO
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Advanced Mobile Phone System (AMPS)Advanced Mobile Phone System (AMPS)
1st Generation U.S. Cellular1st Generation U.S. Cellular Analog FDMAAnalog FDMA
30 KHz FM channels30 KHz FM channels # of subscribers peaked in 1999# of subscribers peaked in 1999 February 18, 2008February 18, 2008
FCC no longer required carriers to supportFCC no longer required carriers to support Should now be called OMPSShould now be called OMPS
RIP
1G AMPSFDMA1G AMPSFDMA
frequency
tim
eDifferent channels use some of the frequency all of the time.
1 32 4Cell 1Cell 2
AMPS
1G Backhaul1G Backhaul
Typically a T-1 Typically a T-1 23 calls23 calls 1 signaling channel1 signaling channel
14.4 Kbps data per user14.4 Kbps data per user Voice Backhaul Voice Backhaul
Moving a little data on the sideMoving a little data on the side
2G Mobile Wireless (MAN) 2G Mobile Wireless (MAN)
Time Division Multiple AccessTime Division Multiple Access U.S. TDMA, 2G, gone U.S. TDMA, 2G, gone → GSM→ GSM GSM, 2G, Data Speeds GSM, 2G, Data Speeds << 14.4 Kbps 14.4 Kbps
ObsoleteObsolete
RIP
2G Mobile Wireless (MAN) 2G Mobile Wireless (MAN)
Time Division Multiple AccessTime Division Multiple Access U.S. TDMA, 2G, gone U.S. TDMA, 2G, gone → GSM→ GSM GSM, 2G, Data Speeds GSM, 2G, Data Speeds << 14.4 Kbps 14.4 Kbps
ObsoleteObsolete
Code Division Multiple Access Code Division Multiple Access TIA-95 CDMA (a.k.a. IS-95 or CDMA1), 2GTIA-95 CDMA (a.k.a. IS-95 or CDMA1), 2G
Data Speeds Data Speeds << 14.4 Kbps 14.4 KbpsObsoleteObsolete
RIP
+1
-1time
time
time+1
-1-1-1
+1 +1 +1
Traffic(9 Kbps)
SpreadingSignal27 Kcps
TransmittedSignal27 Kcps(mappedonto hi freq)
+1 +1+1
-1 -1
DSSS - Transmit Side
Wireless Wireless
X
27 KcpsSquare Pulses
cos(2πfct)
BPSK output27 Kcps90% of power in 54 KHz BW
centered at fc Hertz
X
cos(2πfct)
BPSK input27 Kcps+ noise
27 KcpsSquare Pulses+ filtered noise
RCVR Front End
RF Transmitter
Low PassFilter
time
time+1
-1-1-1
+1 +1 +1DespreadingSignal27 Kcps
ReceivedSignal27 Kcps
+1 +1+1
-1 -1
+1
-1
timeRecoveredTraffic9 Kbps
DSSS-Receiver
time+1ReceivedSignal #227 Kcps
-1 -1
timeRecoveredGarbage from 2ndsignal -1 -1
+1
+1 +1+1
time
-1-1
+1 +1 +1DespreadingSignal #127 Kcps
+1 +1
-1
DSSS-Receiver2nd Signal active
-1
Input toMatchedFilterDetector(sum)
+1
-1
timeRecoveredTraffic9 Kbps
timeRecoveredGarbage from 2ndsignal -1 -1
+1
+2
+1
-1
+1
-2
time
DSSS-Receiver2 Signals active
ReceiverMatchedFilterDetectorOutput
Additional signals transmitting at the same time increase the apparent noise seen by our system.
Message (voice) BER will increase.
+1
-1 time
Input toMatchedFilterDetector(sum)
+2
-2
time
TBit
CDMACDMAfrequency
tim
eDifferent channels use all of the bandwidth all of the time.
Channels use different codes. Other channels cause noise-like interference.
Multiplexing SchemesMultiplexing Schemes
Frequency Division MutiplexingFrequency Division Mutiplexing Time Division MultiplexingTime Division Multiplexing Statistical MultiplexingStatistical Multiplexing Code Division MultiplexingCode Division Multiplexing
2G Backhaul2G Backhaul
Still Frequently T Carrier Still Frequently T Carrier T1's or a maybe a T3T1's or a maybe a T3
14.4 Kbps – 200 Kbps data per user14.4 Kbps – 200 Kbps data per user Primarily Voice Backhaul Primarily Voice Backhaul
Moving a little more data on the sideMoving a little more data on the side
Mobile Wireless EvolutionMobile Wireless Evolution
Developmenthalted in 2005
2G: Voice! Voice!2.5G: One eye
on data.3G: Voice & Data4G: Hi Speed Data
LTE(4G)
WiMax
Sprint2012-2013
3G Mobile Wireless (MAN)3G Mobile Wireless (MAN) Universal Mobile Telephone Service (UMTS)Universal Mobile Telephone Service (UMTS)
3G GSM, Data Rates from 384 Kbps to 2+ Mbps3G GSM, Data Rates from 384 Kbps to 2+ Mbps Wideband CDMA, 5 MHz BWWideband CDMA, 5 MHz BW
High Speed Packet Access (HSPA)High Speed Packet Access (HSPA) 3G GSM, UMTS upgrade, data 3G GSM, UMTS upgrade, data << 2(4+) Mbps up(down)link 2(4+) Mbps up(down)link W-CDMA: more codes & higher M-Ary for dataW-CDMA: more codes & higher M-Ary for data
Code Division Multiple Access 2000 (CDMA 2000)Code Division Multiple Access 2000 (CDMA 2000) 3rd Generation 3rd Generation Data Rates 200 Kbps to maybe 3+ Mbps Data Rates 200 Kbps to maybe 3+ Mbps
3G Backhaul3G Backhaul
T3's & SONETT3's & SONET ATM or IP BasedATM or IP Based
Some Carrier EthernetSome Carrier Ethernet Mixed Traffic EnvironmentMixed Traffic Environment
Orthogonal FDMOrthogonal FDMfrequency
tim
e
Channels split into sub-channelsBits parceled out to sub-channels
Advantage:Sub-channel bit rates can be modified to cope with narrow band interferenceLess susceptible to multipath
Channel 1
FDM with Multi-pathFDM with Multi-path
XMTR
RCVRdirect path
bounce path
direct path pulsesbounce path pulses
Signal sum seen by Receiver
T2 T3 Symbol decision intervals at Receiver.The third bit is obliterated by multi-path.
T3time
delay
T1
OFDM with Multi-pathOFDM with Multi-path
direct
T3
bounce
directbounce
directbounce
T2T1
Matched filter detector will work OK.
delay
Slower symbol rate over each subchannel.
Hybrid ARQHybrid ARQ
Standard ARQStandard ARQ Resend packet if it arrives corruptedResend packet if it arrives corrupted TCP does thisTCP does this
Hybrid ARQHybrid ARQ Save contents of corrupted packetSave contents of corrupted packet Request a retransmissionRequest a retransmission Combine ResultsCombine Results
Hybrid ARQHybrid ARQ Hard Decision Matched Filter Bit DetectorHard Decision Matched Filter Bit Detector
Sample Bit Multiple TimesSample Bit Multiple Times Compute an AverageCompute an Average If Average > Threshold, Call it a Logic 1If Average > Threshold, Call it a Logic 1 If Average < Threshold, Call it a Logic 0If Average < Threshold, Call it a Logic 0
Won't Work Well With Hybrid ARQWon't Work Well With Hybrid ARQ Suppose 00101100 flunks CRCSuppose 00101100 flunks CRC Suppose 00011100 retrans also flunks CRCSuppose 00011100 retrans also flunks CRC Are 3rd and 4th Bits 1's or 0's?Are 3rd and 4th Bits 1's or 0's?
Hybrid ARQHybrid ARQ
Soft Decision Matched Filter Bit DetectorSoft Decision Matched Filter Bit Detector Sample Bit Multiple TimesSample Bit Multiple Times Compute an AverageCompute an Average How Far From Threshold?How Far From Threshold?
Barely Above? Could Say "It might be a Logic 1"Barely Above? Could Say "It might be a Logic 1" Above? Could Say "It's probably a Logic 1"Above? Could Say "It's probably a Logic 1" Well Above? Could Say "It's very likely a Logic 1"Well Above? Could Say "It's very likely a Logic 1" Far Above? Could Say "I'm positive it’s a Logic 1"Far Above? Could Say "I'm positive it’s a Logic 1"
Ditto for Voltages Below ThresholdDitto for Voltages Below Threshold
Hybrid ARQHybrid ARQ Soft Decision Matched Filter Bit DetectorSoft Decision Matched Filter Bit Detector Suppose 00Suppose 0010101100 flunks CRC1100 flunks CRC
Suppose Average for 3rd bit barely aboveSuppose Average for 3rd bit barely above Suppose Average for 4th bit barely belowSuppose Average for 4th bit barely below
Suppose 00Suppose 0001011100 retrans also flunks CRC1100 retrans also flunks CRC 3rd bit average far below → Positive it's a Logic 03rd bit average far below → Positive it's a Logic 0 4th bit average barely above → Iffy Logic 14th bit average barely above → Iffy Logic 1
Byte probably is 00Byte probably is 00000011001100 We're pretty sure 3rd bit is a Logic 0We're pretty sure 3rd bit is a Logic 0 4th bit can't be a 1, as 00011100 flunked CRC4th bit can't be a 1, as 00011100 flunked CRC
4G Backhaul4G Backhaul
Frequently SONETFrequently SONET IP & MPLS BasedIP & MPLS Based
Some Carrier EthernetSome Carrier Ethernet Bursty Data EnvironmentBursty Data Environment
Hauling a little Voice over IP on the sideHauling a little Voice over IP on the side