Student Presentations

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• Student Presentations

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WiMaxEd Katz, ECE410

• Worldwide Interoperability for Microwave Access

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Certification awarded by the Wimax Forum, an
industry group

• Interoperability
• Compliance to IEEE 802.16 standards
• WiBro- South Korean service based on 802.16.
  WiBro products are expected to be certified
  during 2007
• HiperMAN European standard software support in
  versions 802.16.c forward

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Interoperability

• Determined at forum certified labs
• AT4 Wireless (formerly ETECOM Spain)
• Telecommunications Technologies Association IT
  Testing Certification (Seoul, Korea)
• Testing of base station and subscriber station
  products
• As of 31Oct2006 approximately 30 fixed wireless
  broadband products have been certified

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IEEE 802.16

• Developed by IEEE working group 802.16 on
  Broadband Access standards
• Standards are established for air interface
  between Subscriber and Base transceivers
• Divided into Physical and Media Access Control
  Layers

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Physical Layer

• Frequency Band
• 10 GHz- 66 GHz 2 GHz- 10 GHz
• Modulation Schemes
• Various, including QPSK, 16-QAM, 64-QAM
• Error Correction (Reed-Solomon GF256)
• Synchronization
• Data Rate
• Time Division Multiplexing

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MAC Layer

• Controls all issues of providing service to
  subscribers
• Allocates physical layer resources to
  applications
• Convergence sub layer
• Defines functions specific to service
  applications, i.e. telephony, internet access,
  Audio/Video multicast

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Applications
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Applications- telephony
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Applications- Broadband internet
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Applications-Broadband internet
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Vendors Products

• Motorola
• TK101151B Canopy
• Base station, 6 Access points
• 1200 subscribers
• 24,700 list
• TK10190B Canopy
• 900 MHz Unlicensed
• 30 Subscriber stations
• 17,050

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Vendors Products, cont.

• Airspan
• HiperMAX base station w/mobility
• Micromax
• Adaptix
• BX3000
• Alvarion
• Breezmax

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Rural Service Provider

• Altius Broadband
• Rural MD
• Motorola 900 MHz (unlicensed)
• 50k build out, 200 customers per tower
• Customer Premise Equipment 300 each
• Licensed Bands (2.3, 2.5 GHZ)
• 40k per sector per base station
• 10k to commission base station
• 250 per CPE

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Research focus

• Price trends
• What services are being provided?
• Mainly affects CPE prices
• Determine trends in other technologies
• i.e. WiFi, Cable Connections, etc
• Determine cost of HW vs Software
• Other resources
• Research librarians at PSU Library have been
  contacted
• They recommend primary research , i.e. writing
  to companies and asking them
• Various databases accessible through library
• Mostly Economics and Business
• Provide trends a for industry expenditures, but
  not specific prices
• Complimentary research

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WiFi vs WiMAX
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WiFi - Wireless Fidelity

• WiFi is IEEE 802.11 Standard.
• WiFi has gained a lot of popularity in the recent
  years.
• Intended for wireless Local Area Networks.
• Typical range of WiFi is 150ft indoors and 300ft
  outdoors.
• Greatly simplifies the setup of a network.
• Limits the amount of wire that needs to be
  placed.
• Network can be up and running in less time.
• For obvious reasons WiFi is very popular with
  Portable Devices.

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Flavors of IEEE 802.11

• IEEE 802.11 or WiFi is broken down into a few
  different releases.
• 802.11b
• First to hit to market
• Least expensive to implement
• Operates at 2.4 GHz
• Data rate of 11Mbps.
• 802.11a
• Second to hit the market
• Operates at 5 GHz
• Data rate of 54 Mbps
• 802.11g
• Last to emerge
• Operates at 2.4 GHz
• Data rate of 54 Mbps

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Basic WiFi Components

• Wireless Access point (WAP or AP)
• If you have a broadband connection and a router
  in place, but would like to add wireless
  capabilities to your network, then you need to
  obtain a WAP.
• The WAP transmits the signal that is then picked
  up by the wireless devices.
• This can be looked at as the door between your
  wired network and your wireless network.

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Basic WiFi Components

• If you are building a new network and intend for
  it to have wireless capabilities from the
  beginning, then a wireless router would be a good
  choice.
• A wireless router will provide the services of a
  WAP, but at the same time provide that which is
  needed to manage wired networks all in one
  package.

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Basic WiFi Components

• Repeater or Extender
• If you want coverage beyond your AP range, then a
  repeater is required.
• A repeater simply takes a signal, amplifies it
  and rebroadcasts it.
• Some repeaters will also offer other
  functionality.

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Cantenna

• A primitive device referred to as the Cantenna
  can be used to considerable improve the range of
  the transmitter/receiver.
• A cantenna is basically a can that is transformed
  into an antenna to amplify the WiFi signal.
• This fancy device can be manufactured for under
  5 dollars.
• It is recommended that a can slightly longer then
  a Pringles container be used for best results.
• A Cantenna can provide between 12 and 15dB gain.
• Signal range can be improved by something like
  1000ft
• Instructions for doing it yourself
• http//www.turnpoint.net/wireless/cantennahowto.ht
  ml

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Cantenna
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Basic WiFi Components

• Wireless Network Cards
• Used on the end systems to communicate with
  network.
• Comes in ISA, PCI, USB, PCMCIA

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WiFi Network Topology

• Above is a typical WiFi network topology.
• A router is connected to the internet.
• A wireless access point is connected to the
  router.
• All wireless devices are connected to the
  wireless access point.

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WiFi Network Topology

• This is an example of a more complicated Mesh
  WiFi network.
• Here we have a router connected to the Internet.
• We then have a wireless access point connected to
  the router.
• However do to the limited range of WiFi (150
  300 ft) repeaters are used to provide greater
  coverage.

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Cons and Pros of WiFi

• Cons
• Limited signal range
• Not very secure
• Requires wired internet nearby
• Intended for small to medium networks
• Cost of network card is still pretty high

• Pros
• Fast network setup
• No cable runs
• Portability
• One AP can handle gt100 connections
• Service more people for a lower price

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WiMAX - Worldwide Interoperability for Microwave
Access

• WiMAX is a IEEE 802.16 standard
• Designed for Metropolitan area networks (MAN)
• Maximum radius of 30 miles
• Data rate 70 Mbps
• Signal Frequency
• 2 to 11 GHz - Out of sight
• 10 to 66 GHz In sight
• Intended to provided broadband internet coverage
  to large areas.

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Implementing WiMAX

• Two elements define a WiMAX network
• Base Station WiMAX tower
• Connects to the internet and broadcasts the
  signal out to end users.
• Receiver
• Typically this is a wireless network card that
  receives the signal.

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WiMAX Network Topology
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Cons and Pros of WiMAX

• Cons
• Network more complex
• More time to setup
• More Expensive to Implement
• Actual range used is much less then maximum range
  advertised for this technology.
• Typical Radius is 4 to 6 miles
• Does not resolve expense of wireless card.

• Pros
• High data rates
• Good Encryption
• No cable runs required
• Does not require line of sight connection
• Transmits over a wide range

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WiFi or WiMAX?

• Are these two technologies the same?
• Are they fighting for the same market?
• Which is better?

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WiFi or WiMAX?

• Both technologies aim to provide wireless
  communication.
• However they are considerably different and have
  been designed for different purposes.
• Each is good for the purpose that they were
  designed for.
• Therefore they are not fighting for the same
  market.

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WiFi

• WiFi is intended to be used for Local Area
  networks.
• Your house or a coffee shop.
• Not intended for Metropolitan Area Networks.
• Short range, even with cantenna range extenders
  compared to WiMAX.
• Weak encryption compared to WiMAX.
• AP responds on request and if the end users are
  far, they may experience starvation due to closer
  users.

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WiMAX

• Designed for Metropolitan Area Networks.
• Very large coverage.
• Secure data transmission.
• AP allocates end hosts a time slice.
• Requires you to fight for connection once, then
  you are allocated resources for remainder of
  time.
• Allows one tower to connect to another, this is
  called backhaul.
• Reduces out of sight communication frequency to
  ensure better data transmission.

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Winter 07 Midterm Solutions

• I.                  Lost in Space
• The International Space Station (ISS) is in a
  circular orbit 354 Km above the earths surface.
  (Earth radius is 6,370 Km.)
• (a) How long is the line of sight from the ISS
  to the earths horizon.?                  
• (b)       (b)The orbit time, once around the
  Earth, takes 91.61 minutes. Anousheh Ansari, the
  Iranian tourist astronaut was aboard for 8 days.
  How far did she travel?
• (c)        (c)The orbit is inclined 51.6 degrees
  from the equatorial plane. What is the farthest
  North Latitude that you can see from the space
  station?

(a) D sqrt( 63703542 -63702) sqrt(67242-
63702) 2,153 Km (b) She made 8 x 24 x 60/91.61
125.75 orbits Each orbit was 2p R 2p 6724
42,248 Km total 42248 x 125.75 5,312,703 Km
(c) See right arcsin 2153/6724 18.6. Latitude
18.6 51.6 70.27 deg N
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II. WiFi and WiMAX
Antenna Factory 2.4 GHz Grid
Antenna 13.5 dBi, SMA female connector 65.00
Each

• WiFi is a band at 2.4 GHz, limited to 40
  milliwatts transmitter power and 6 dB antenna
  gain. The bandwidth is 20 MHz and the C/N is 10
  dB.
• (a) Assuming the transmitter has 40 milliwatts
  and 6dB gain, what is the range for a receiver
  with 0 dB gain and 300 deg K receiver Temp.?
• (b) Where allowed, WiFi can be connected to
  high-gain antennas costing only 65 and having a
  gain of 13.5 dB. What is the range if the
  antennas are used at both transmit and receive
  with the 40 milliwatt transmitter?
• (c) What is the range for part (b) if in addition
  we cut the bandwidth to 2 MHz?

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• (a)            EIRP 6 10 log .040 -8 dB B
  206gt 73 dBHz C/N 10
• G/T 0 - 10 log 300 -24 dB.
• EIRP G/T Lfs B C/N k
• Lfs B C/N k EIRP G/T
• Lfs 73 10 - 228.6 8 24 -113.6gt 4.36 x
  10-12 Lfs (l/4pR)2
• l 3x108/2.4x109 .125 M
• R (l/(4p sqrt 4.36 x10-12) 4.76 Km
• (b) Total improvement 13.5 13.5 6 21 dB
  gt 125
• Range goes as sqrt( gain )
• Rb 4.76 x sqrt(125) 53 Km
• (c) Reducing B by 10/2 5 increases range by
  sqrt(5) Rc 119 Km

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III. Community Radio Stations

• The 1000 community radio broadcast station works
  at a frequency of 100 MHz. The bandwidth is 180
  kHz and requires 10 dB C/N for good reception.
  The transmit antenna has 4 dB gain. The receivers
  have a total noise temperature of 700 deg. K.
• (a)                        How much effective
  area does the receive antenna have? Its gain is 1
  dB.
• (b)                        What range will you
  have with the 75-Watt FM transmitter?
• (c)What range for an indoor receiver including 20
  dB loss for walls and/or trees.
• (d)                        What range will you
  have with a 5 dB gain outdoor receiving antenna
  with no loss?

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• (a) Aeff l2 Gr/4p l 3 x 108/100x106 3
  Meters
• G 1 dB gt 1.26
• Aeff 3 x 3 x 1.26/ 4p 0.9 M2
• (b) G 1dB C/N10dB EIRP 4 log 75 4
  18.722.7dBW
• G/T 1 log 700 1-28.4 -27.4 B 180kHz gt
  52.5 dBHz
• Lfs B C/N k EIRP G/T
• Lfs 52.5 10 228.6 22.7 27.4 -161.4
  dBgt7.24 x 10-17
• R (l/(4p sqrt 7.24 x10-17) 9,174 M 28, 060
  Km
• (c) With 20 dB loss you get 10 dB less range or
  2,806 Km.
• (d) With 5 dB outdoor antenna you get (5-1)
  dBgt2.5 greater gain. Therefore sqrt(2.5) greater
  range than in part (b), or 44,367 Km.

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IV. Tidal Wave

• A tsunami is triggered off Mindanao, the
  Philipines, at 8 deg N Lat, 128 deg. E
  Longitude. (a) How long does it take to reach
  Papua, New Guinea. at 3 deg S Lat, 140 deg East
  Longitude? Tsunamis travel at an average of 740
  Km/Hr.(b) The AsiaSat is used to broadcast the
  warning at 4 GHz to 0.5 meter antennas, 45
  efficiency, with 150 deg K noise temperature.
  What EIRP is needed if the signal is 50 kHz and
  10 dB C/N?

(a) The two sides of the triangle from the North
Pole are 82 and 93 degrees and the included angle
is 12 degrees. The third side therefore
is Arccos cos 82 Cos 93 sin 82 sin 93 cos
12Arccos.00728-.9673 16.25 deg. Distance 2
p 6,370 x 16.25/360 1,806 Km Time is 1806/
740 2.44 hours (b) EIRP B C/N k G/T- Lfs
G 0.45(p 0.5/0.075)2 197gt22.9dB EIRP 47
10 228.6 22.9 21.7 197.6 24.8 dBW/M2
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Homework 4 Due Wed February 28
Ill email a short exercise on cash flow and
investment in rural telecom and infrastructure
tomorrow. In the mean time the other part of the
assignment is to prepare the first overview
report on the rural areas of the countries youve
chosen for your final report. The overview can
incorporate the material you provided for the
first homework, working towards the final study.
Ill comment on these for your final report. The
report and the economic analyses are due
Wednesday Feb 28
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Quantization and coding using 16 equal steps
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Standard M-Law PCM 8 segments (3 bits)16
steps each(4 bits) sign (1 bit)8
bits/sample,8,000 samples/sec64,000 bits/sec
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In U.S. standard the lowest order bit of each
channel is stolenevery 6th frame for signaling
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Multiplexing Hierarchy, U.S. Standards
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Comparison of PCM Multiplex Hierarchies
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Digital Encoders
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Variable-Slope Delta Modulation
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Digital Engineers normally use a different set of
parameters to describe performance

• R is the data rate (bits/sec)
• R/W is the Spectral Efficiency (bits/sec per Hz )
• W is the same as B Bandwidth
• Eb/No is the power efficiency
• (joules/bit in the signal
• over joules/Hz in the noise)

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• For Information Theory analyses, C/N is normally
• replaced by the energy per bit, Eb,
• and the noise power Density No, (watts/hz).
• The relationship is
• Eb C(watts)/R(bits/sec) C Eb x R
• No N(watts)/W(hertz bandwidth) N No x W
• Shannon's Law
• R/W Log 2( Eb/No x R/W 1 )
•   . In performance of actual equipment the
  parameters are usually specified as
• Spectrum utilization R/W (from 0.8 to 4
  typical)
• Modulation efficience Eb/No (from 9.4 to 12.5)

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Converting to Radio Engineers JargonSubstitute
the following into the Link Equations for B, C/N
and C/kTand the rest is the same
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Example Digital TV (R4Mb/sec) Transmitted by
Quadrature Phase Shift Keying,

• QPSK (Eb/No 9.9 dB, R/W 1.9 gt2.8 dB
• B 4Mb/s /1.9 2.10 MHz
• C/N Eb/No x R/W 9.92.8 12.7 dB
• "C/kT"l0 log10(4xl0 6) 9.9
• 66.09.975.9 dB

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Shannon's Law

• The theoretical limit of transmitted bit rate and
  signal to noise ratio is given by Shannon's Law.
  Practical systems strive towards the limits but
  are constrained by equipment limitation, handling
  of errors, repeat transmissions, and practical
  signal processing.
• Shannon's Law
• R bit rate Wbandwidth
• C received power N received noise

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Shannons LawC/kT R x Eb/No
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Conceptual Explanation

• Noise sets the uncertainty of resolution of K
  related
• to the ratio of Power and Noise
• K( Pr / Pn l)
• If you can resolve each sample into K values, you
  can derive k bits from each sample by the binary
  representation 2kK. k is then the number of
  bits that can be derived from the sample.

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Systems with 1 kB/sec at 10 -4 BER
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Systems with 1 kB/sec at 10 -4 BER
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Modulation Noise Sensitivity
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16 Amplitude-Phase Plots for Maximum-Distance-
Modulation(MDM)ImprovementonShannonsLaw
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Comparative Performance of MDM