Term Paper 14 November – Remote DL Late Fee = -1 point per working day Final Exam Live: 10:00 – 11:50 AM, Monday, 8 December DL: Not Later than Monday, 15 December ECEN5553 Telecom Systems Dr. George Scheets Week #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 = A > 81, B > 66, C > 57, D > 48 Term Paper 14 November – Remote DL Late Fee = -1 point per working day Final Exam Live: 10:00 – 11:50 AM, Monday, 8 December DL: Not Later than Monday, 15 December

Final Exam n Work 5 of 7 pages n pages will be from the Fall '13 final n 85-90% Notes 10-15% Readings n Use the space provided! # Facts should be > number of points etc. Start Reviewing Now!

Syllabus Grade Break Points n A > 410 points (90%) n B > 364 points (80%) n C > 319 points (70%) n D > 273 points (60%) n > 410 points? Guaranteed an A n > 364 but 364 but < 410? Guaranteed a B, etc. n Otherwise, at mercy of Court

Fall 2013 Break Points n A > 387 points (85%) n B > 341 points (75%) n C > 296 points (65%) n D > 250 points (55%) n Fall 2014 points likely not the same. u Probably in same vicinity u Won't know for sure until everything's graded

Satcom & Flat Panel Antenna Arrays USS Lake Champlain: Aegis Guided Missile Cruiser image source: wikipedia

Bit Error Rate Unsatisfactory? System designer has several options: n Use FEC codes n Increase received signal power u Crank up transmitter power out u Use directional antennas n Use more effective modulation technique n Slow down the transmitted symbol rate n Use less noisy receiver electronics

Voyager II Deep Space Probe n Used all of previous techniques on downlink: u 2:1 FEC Coding (different code than in previous examples) u Increasingly sophisticated earth receive antennas u Binary PSK signaling u Reduced bit rates u Cryogenically cooled receiver electronics n Flight history u Launch, August 1977 u Jupiter fly-by, July 1979, Message bit rate: Kbps u Saturn fly-by, August 1981, Message bit rate: 44 Kbps u Uranus fly-by, January 1986, Message bit rate: 29.9 Kbps u Neptune fly-by, August 1989, Message bit rate: 21.6 Kbps u Now well past Pluto. NASA is still in contact.

Pre-Cellular Mobile Telephony source: Telecommunications by Warren Hioki, 1st Edition

0 th Generation Mobile Phones Source:

Cellular Telephone System source: Telecommunications by Warren Hioki, 1st Edition ISP

Cellular Telephony Advantages: n n Frequency Reuse n n Reduced Transmitter Power Out n n Reduced Multipath Problems n n Reduced brain damage? n n Subdividing Cells increases System Capacity n n More Reliable due to cell overlap

Cellular Telephony Disadvantages: n More complex n More installation hassles n BS to MTSO link (Backhaul) & switching requirements can get out of hand

1987 Mobile Phone source: September 1987 Electronic Design Magazine

Techniques to Increase Bit Rate (Per Channel Basis) n Use FEC n Increase Received Signal Power n Change Modulation Technique n Build a Quieter Receiver n Slow Down Transmitted Bit Rate n Increase Available Bandwidth n Compress the Application Signal u Increases apparent bit rate

One Big Cell 30 Channels could support 30 users

Seven Smaller Cells Set #3 10 Channels Set #1 10 Channels Set #2 10 Channels Can Support 70 Users with same Channel set.

Mobile Traffic Source: "The Great Spectrum Famine", IEEE Spectrum Magazine, October 2010.

London, 1995

Hidden Cell Towers sources: businessweek.com mobilitydigest.com

Cellular Telephony - Operation Power Up & Intermittently Thereafter n Mobile tunes to strongest control channel n Mobile communicates with BS/MTSO n Local MTSO notes in database mobile is active & which cell it's in n If mobile is roaming, Home MTSO is notified, typically via SS7 or SIP Signaling

Cellular Telephony - Operation Mobile to Wired call n Mobile transmits # to BS/MTSO u Uses Control Channel n Unused voice RF channel is assigned u Mobile tunes to assigned channels n BS & MTSO coordinate Backhaul n MTSO places call via CO to wired unit u Could be via PSTN or VoIP

Cellular Telephony - Operation Wired to Mobile call n Signaling info shipped to home MTSO n Home MTSO checks database u Mobile in home area? Mobile is paged u Mobile not in home area? Signaling info is forwarded to local MTSO Local MTSO database indicates Mobile's cell Mobile is paged & tunes to assigned RF channel n End-to-End Voice channel is set up u BS & MTSO coordinate Backhaul u MTSO & CO coordinate Long Haul

Cellular Telephony - Operation n Handoff MTSO/BS/Mobile decides signal getting too weak Adjacent cells are polled Unused voice RF channels in the new cell is assigned Mobile tunes to assigned channel MTSO reroutes traffic: Old BS  MTSO to New BS  MTSO

Wireless WAN Data source: Telecommunications by Warren Hioki, 1st Edition ISP To World x x

Advanced Mobile Phone System (AMPS) n 1st Generation U.S. Cellular n Analog FDMA u 30 KHz FM channels n # of subscribers peaked in 1999 n February 18, 2008 u FCC no longer required carriers to support u Should now be called OMPS RIP

1G AMPS FDMA frequency time Different channels use some of the frequency all of the time Cell 1 Cell 2 AMPS

1G Backhaul n Typically a T-1 u 23 calls u 1 signaling channel n 14.4 Kbps data per user n Voice Backhaul u Moving a little data on the side

2G Mobile Wireless (MAN) n Time Division Multiple Access u U.S. TDMA, 2G, gone → GSM u GSM, 2G, Data Speeds < 14.4 Kbps Obsolete RIP

2G GSM frequency time Combo of TDM & FDM etc Cell 1 Cell 2

2G Mobile Wireless (MAN) n Time Division Multiple Access u U.S. TDMA, 2G, gone → GSM u GSM, 2G, Data Speeds < 14.4 Kbps Obsolete n Code Division Multiple Access u TIA-95 CDMA (a.k.a. IS-95 or CDMA1), 2G Data Speeds < 14.4 Kbps Obsolete RIP

+1 time Traffic (9 Kbps) Spreading Signal 27 Kcps Transmitted Signal 27 Kcps (mapped onto hi freq) +1 DSSS - Transmit Side

Wireless X 27 Kcps Square Pulses cos(2πf c t) BPSK output 27 Kcps 90% of power in 54 KHz BW centered at f c Hertz X cos(2πf c t) BPSK input 27 Kcps + noise 27 Kcps Square Pulses + filtered noise RCVR Front End RF Transmitter Low Pass Filter

time Despreading Signal 27 Kcps Received Signal 27 Kcps time Recovered Traffic 9 Kbps DSSS-Receiver

time+1 Received Signal #2 27 Kcps time Recovered Garbage from 2nd signal +1 time +1 Despreading Signal #1 27 Kcps +1 DSSS-Receiver 2nd Signal active

Input to Matched Filter Detector (sum) +1 time Recovered Traffic 9 Kbps time Recovered Garbage from 2nd signal time DSSS-Receiver 2 Signals active

Receiver Matched Filter Detector Output Additional signals transmitting at the same time increase the apparent noise seen by our system. Message (voice) BER will increase. +1 time Input to Matched Filter Detector (sum) +2-2 time T Bit

CDMA frequency time Different channels use all of the bandwidth all of the time. Channels use different codes. Other channels cause noise-like interference.

CDMA: 3D View code #1 code #2 code #3 frequency time

Multiplexing Schemes n Frequency Division Mutiplexing n Time Division Multiplexing n Statistical Multiplexing n Code Division Multiplexing

2G Backhaul n Still Frequently T Carrier u T1's or a maybe a T3 n 14.4 Kbps – 200 Kbps data per user n Primarily Voice Backhaul u Moving a little more data on the side

Mobile Wireless Evolution Development halted in G: Voice! Voice! 2.5G: One eye on data. 3G: Voice & Data 4G: Hi Speed Data LTE (4G) WiMax Sprint

3G Mobile Wireless (MAN) n Universal Mobile Telephone Service (UMTS) u 3G GSM, Data Rates from 384 Kbps to 2+ Mbps u Wideband CDMA, 5 MHz BW n High Speed Packet Access (HSPA) u 3G GSM, UMTS upgrade, data < 2(4+) Mbps up(down)link u W-CDMA: more codes & higher M-Ary for data n Code Division Multiple Access 2000 (CDMA 2000) u 3rd Generation u Data Rates 200 Kbps to maybe 3+ Mbps

3G Backhaul n T3's & SONET n ATM or IP Based u Some Carrier Ethernet n Mixed Traffic Environment

FDM FDMA frequency time Different channels use some of the frequency all of the time. 1324

Orthogonal FDM frequency time Channels split into sub-channels Bits parceled out to sub-channels Advantage: Sub-channel bit rates can be modified to cope with narrow band interference Less susceptible to multipath Channel 1

FDM with Multi-path XMTR RCVR direct path bounce path direct path pulses bounce path pulses Signal sum seen by Receiver T2T3 Symbol decision intervals at Receiver. The third bit is obliterated by multi-path. T3 time delay T1

OFDM with Multi-path direct T3 bounce direct bounce direct bounce T2T1 Matched filter detector will work OK. delay Slower symbol rate over each subchannel.

Hybrid ARQ n Standard ARQ u Resend packet if it arrives corrupted u TCP does this n Hybrid ARQ u Save contents of corrupted packet u Request a retransmission u Combine Results

Hybrid ARQ n Hard Decision Matched Filter Bit Detector u Sample Bit Multiple Times u Compute an Average u If Average > Threshold, Call it a Logic 1 u If Average < Threshold, Call it a Logic 0 n Won't Work Well With Hybrid ARQ u Suppose flunks CRC u Suppose retrans also flunks CRC u Are 3rd and 4th Bits 1's or 0's?

Hybrid ARQ n Soft Decision Matched Filter Bit Detector u Sample Bit Multiple Times u Compute an Average u How Far From Threshold? F Barely Above? Could Say "It might be a Logic 1" F Above? Could Say "It's probably a Logic 1" F Well Above? Could Say "It's very likely a Logic 1" F Far Above? Could Say "I'm positive it’s a Logic 1" u Ditto for Voltages Below Threshold

Hybrid ARQ n Soft Decision Matched Filter Bit Detector n Suppose flunks CRC u Suppose Average for 3rd bit barely above u Suppose Average for 4th bit barely below n Suppose retrans also flunks CRC u 3rd bit average far below → Positive it's a Logic 0 u 4th bit average barely above → Iffy Logic 1 n Byte probably is u We're pretty sure 3rd bit is a Logic 0 u 4th bit can't be a 1, as flunked CRC

4G Backhaul n Frequently SONET n IP & MPLS Based u Some Carrier Ethernet n Bursty Data Environment u Hauling a little Voice over IP on the side