ECEN4523 Commo TheoryECEN4523 Commo TheoryLecture #35 9 November 2015Lecture #35 9 November 2015Dr. George ScheetsDr. George Scheetswww.okstate.edu/elec-engr/scheets/ecen4533www.okstate.edu/elec-engr/scheets/ecen4533

ECEN4523 Commo TheoryECEN4523 Commo TheoryLecture #35 9 November 2015Lecture #35 9 November 2015Dr. George ScheetsDr. George Scheetswww.okstate.edu/elec-engr/scheets/ecen4533www.okstate.edu/elec-engr/scheets/ecen4533

Read 8.3Read 8.3 Problems: 8.2-5, 6, & 9Problems: 8.2-5, 6, & 9 Quiz #8, 13 November (Live) [Chapter 8]Quiz #8, 13 November (Live) [Chapter 8]

Remote DL students Remote DL students << 20 November 20 November Design Problem Design Problem

Remote DL students Remote DL students << 13 November 13 November Late Designs AcceptedLate Designs Accepted

Cost = -1 point per Working DatyCost = -1 point per Working Daty

ECEN4523 Commo TheoryECEN4523 Commo TheoryLecture #36 11 November 2015Lecture #36 11 November 2015Dr. George ScheetsDr. George Scheetswww.okstate.edu/elec-engr/scheets/ecen4533www.okstate.edu/elec-engr/scheets/ecen4533

ECEN4523 Commo TheoryECEN4523 Commo TheoryLecture #36 11 November 2015Lecture #36 11 November 2015Dr. George ScheetsDr. George Scheetswww.okstate.edu/elec-engr/scheets/ecen4533www.okstate.edu/elec-engr/scheets/ecen4533

Problems: 8.3 – 1, 2, 4, & 6Problems: 8.3 – 1, 2, 4, & 6 Quiz #8, 13 November (Live) [Chapter 8]Quiz #8, 13 November (Live) [Chapter 8]

Remote DL students Remote DL students << 20 November 20 November Design Problem Design Problem

Remote DL students Remote DL students << 13 November 13 November Late Designs AcceptedLate Designs Accepted

Cost = -1 point per Working DayCost = -1 point per Working Day Quiz 7 ResultsQuiz 7 Results

Hi = 10, Low = 4.7, Ave = 8.03, Hi = 10, Low = 4.7, Ave = 8.03, σσ = 2.26 = 2.26

Channel Capacity (C)Channel Capacity (C) Bandwidth, Bit Rate, SNR, and BER relatedBandwidth, Bit Rate, SNR, and BER related Channel Capacity defines relationshipChannel Capacity defines relationship

C = Maximum reliable bit rate C = Maximum reliable bit rate C = W*Log C = W*Log22(1 + SNR) bps(1 + SNR) bps

Bandwidth sets the maximum Baud rateIf move too many Baud, symbols will smear.

SNR sets the maximum number ofdifferent symbols (the "M" in M-ary)you can reliably tell apart.

1999 Silk Road1999 Silk Road During dot.com boomDuring dot.com boom Company selling fiber optic gearCompany selling fiber optic gear Claim: Can move Tbps over 64 KHz BWClaim: Can move Tbps over 64 KHz BW Fiber optic laser center freq 160,000 GHzFiber optic laser center freq 160,000 GHz

Jitter around 64 KHzJitter around 64 KHz

101099 bps = 64000*Log bps = 64000*Log22(1 + SNR)(1 + SNR) 2215,62515,625 – 1 = SNR – 1 = SNR Calculator couldn't find SNR high enoughCalculator couldn't find SNR high enough

2nd Claim2nd Claim

Same time periodSame time period Claim: Claim:

Can move Exobits/sec over power linesCan move Exobits/sec over power lines Won't need fiber optic cablesWon't need fiber optic cables

Power Line CommunicationsPower Line Communications

Image SourceWikipedia

Transformers don't pass high frequency signals.

Power Lines act as AntennasPower Lines act as Antennas

Source: http://www.doobybrain.com/2008/02/03/electromagnetic-fields-cause-fluorescent-bulbs-to-glow/

Lizzy Borden Lizzy Borden Alleged Alleged

18921892Ax Ax

MurdererMurderer

Lizzie Borden took an axeLizzie Borden took an axe

And gave her mother forty whacks.And gave her mother forty whacks.

When she saw what she had doneWhen she saw what she had done She gave her father forty-one. She gave her father forty-one.

Bernoulli Trials & Binomial DistributionBernoulli Trials & Binomial Distribution You must have a two state experimentYou must have a two state experiment

Success or FailureSuccess or Failure Stable probabilitiesStable probabilities

You must be interested in the You must be interested in the numbernumber of successes (or failures)of successes (or failures) Specific order not importantSpecific order not important

The individual experiments must be The individual experiments must be Statistically IndependentStatistically Independent

Need P(Number of Outcomes)?Need P(Number of Outcomes)? 1) Binomial Distribution? 1) Binomial Distribution? 2) If no, think Conditional Probability2) If no, think Conditional Probability

Draw an event treeDraw an event tree Assign probabilitiesAssign probabilities

P(a1)

P(a2)

P(a3)

P(b1|a1)

P(b2|a1)

P(b4|a2)

P(b6|a3)

P(a1∩b1)

P(a2∩b3)

P(a1∩b2)

P(a2∩b4)

P(a3∩b5)

P(a3∩b6)

P(b3|a2)

P(b5|a3)