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

1987 Mobile Phone1987 Mobile Phone

source: September 1987Electronic Design Magazine

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

One Big CellOne Big Cell

30 Channelscould support

30 users

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.

London, 1995London, 1995

Hidden Cell TowersHidden Cell Towers

sources: businessweek.commobilitydigest.com

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

Wireless WAN DataWireless WAN Dataso

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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 GSM2G GSMfrequency

tim

eCombo of TDM & FDM

1

2

3

1etc.

4

5

6

4

7

8

9

7

10

11

12

10

Cell 1Cell 2

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.

CDMA: 3D ViewCDMA: 3D View

code #1

code #2

code #3

frequency

time

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

FDMFDMAFDMFDMA

frequency

tim

eDifferent channels use some of the frequency all of the time.

1 32 4

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