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Why-Fi A HAM Radio & 802.11 b/g/a/n Presentation Fixed Infrastructure 11/13/2010© 2010 Justin Richert KDØIQV1.

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Presentation on theme: "Why-Fi A HAM Radio & 802.11 b/g/a/n Presentation Fixed Infrastructure 11/13/2010© 2010 Justin Richert KDØIQV1."— Presentation transcript:

1 Why-Fi A HAM Radio & 802.11 b/g/a/n Presentation Fixed Infrastructure 11/13/2010© 2010 Justin Richert KDØIQV1

2 Introduction Agenda Safety First FCC Rules Modulation Algorithms Industry Standards Fun Stuff 11/13/2010© 2010 Justin Richert KDØIQV2

3 Safety First 2.4 Ghz – This is the microwave spectrum This spectrum causes water molecules to excite and heat up – Your Microwave uses this spectrum to cook things – You can cook yourself if you aren’t careful – Never stand in the radiation area of a high power RF antenna (especially with this band) 11/13/2010© 2010 Justin Richert KDØIQV3

4 Safety First This is your brain on 2.4 GHz Research by NASA in the 1970s has shown microwaves cause thermal expansion in parts of the inner ear – humans hear clicks and buzzing sounds. When injury from exposure to microwaves occurs, it usually results from dielectric heating induced in the body. Exposure to microwave radiation can produce cataracts by this mechanism, because the microwave heating denatures proteins in the crystalline lens of the eye. Produces heat damage in other tissues, up to and including serious burns, which may not be immediately evident because of the tendency for microwaves to heat deeper tissues with higher moisture content. 11/13/2010© 2010 Justin Richert KDØIQV4

5 Regular Consumer FCC Part 15 Rules (non amateur radio) Regulated by EIRP & antenna directionality Permissible under Part 15: Max. Transmitter RF power Ant. gain (dBi)EIRP (W) 2.4 GHz directional29 dBm (800 mW)96.35 28 dBm (640 mW)1210.14 27 dBM (500 mW)1515.81 26 dBm (400 mW)1825.23 25 dBm (320 mW)2140.28 24 dBm (250 mW)2462.79 23 dBm (200 mW)27100.2 22 dBm (160 mW)30160.0 2.4 Ghz Note transmitter power decrease as antenna gain increases - spec 1 Watt (+30dbm), through 6dbi omni-directional antenna for 36dbm per system 11/13/2010© 2010 Justin Richert KDØIQV5

6 Regular Consumer FCC Part 15 Rules (non amateur radio) Regulated by EIRP & antenna directionality 5 Ghz Permissible under Part 15: Max. Transmitter RF power Ant. gain (dBi)EIRP (W) 5.15-5.25 GHz omni-directional 16 dBm (40 mW)60.16 5.25-5.35 GHz omni-directional 23 dBm (200 mW)60.80 5.725-5.825 GHz omni-directional 30 dBm (1 W)63.98 (36dbm) 5.725-5.825 GHz directional 30 dBm (1 W)28630.9 11/13/2010© 2010 Justin Richert KDØIQV6

7 HAM FCC Part 97 Rules Note: Part 97.311 & 97.313 Part 101 Fixed Microwave Services The 2300-2305 MHz segment is allocated to the amateur service on a secondary basis. (Currently the 2300-2305 MHz segment is not allocated to any service on a primary basis.); The 2305-2310 MHz segment is allocated to the amateur service on a secondary basis to the fixed, mobile, and radiolocation services; The 2390-2400 MHz segment is allocated to the amateur service on a primary basis - below the 802.11b/g channels The 2400-2402 MHz segment is allocated to the amateur service on a secondary basis. (Currently the 2400-2402 MHz segment is not allocated to any service on a primary basis.) The 2402-2417 MHz segment is allocated to the amateur service on a primary basis – overlaps 802.11b/g channels -2 to 3 The 2417-2450 MHz segment is allocated to the amateur service on a co- secondary basis with the Government radiolocation service – overlaps 802.11b/g channels 1 to 10 Amateur stations operating within the 2400-2450 MHz segment must accept harmful interference that may be caused by the proper operation of industrial, scientific, and medical devices operating within the band. 11/13/2010© 2010 Justin Richert KDØIQV7

8 2.4GHz 802.11b/g channels 11/13/2010© 2010 Justin Richert KDØIQV8

9 HAM FCC Part 97 Rules Amateur Radio regulated by transmitter power with use of any antenna design of any gain Achievable under Part 97: Max. PEP RF powerAnt. gainEIRP* 900 MHz (spread spectrum) 10 watts 14 dBd yagi (16.1dbi) 411.9 watts 2.4 GHz (spread spectrum i.e. 802.11 or 802.1 1b)802.11802.1 1b 10 watts 24 dBi partial parabolic 2511.89 watts 2.4 GHz (non spread spectrum i.e. 802.11g)802.11g 1500 watts (per 97.313)per 97.313 24 dBi partial parabolic 376.8 Kilo-watts 5.7 GHz (non spread spectrum i.e. 802.11a)802.11a 1500 watts (per 97.313)per 97.313 28 dBi dish946.4 Kilo-watts 11/13/2010© 2010 Justin Richert KDØIQV9

10 HAM FCC Part 97 Rules Achievable – Meaning You should still use minimum xmit power Pecuniary Interest – The communications you make under Part 97 must be to and from licensed amateurs. These communications cannot be made with a pecuniary interest and may not be obscene or indecent – Amateur stations may not provide internet service in competition to commercial service, even if provided at no price 11/13/2010© 2010 Justin Richert KDØIQV10

11 Direct Sequence Spread Spectrum (DSSS) Direct-Sequence Spread Spectrum (DSSS) is a modulation technique where the transmitted signal takes up more bandwidth than the information signal that is being modulated. The name 'spread spectrum' comes from the fact that the carrier signals occur over the full bandwidth (spectrum) of a device's transmitting frequency. Sub-carriers are continuously transmitted The resulting signal resembles white noise to a conventional receiver Signal intelligence can be extracted when the signal level is below the noise level Resistant to intended or unintended jamming Reduced signal/background-noise level hampers interception (stealth) Requires high power CPUs and complex mathematical software processing with highly accurate clocking Cannot be built with electronic components only 11/13/2010© 2010 Justin Richert KDØIQV11

12 Direct Sequence Spread Spectrum (DSSS) Uses Used in The United States GPS and European Galileo satellite navigation systems Used in Cordless phones operating in the 900 MHz, 2.4 GHz and 5.8 GHz bands Used in 802.11b Wireless in conjunction with CCK DS-CDMA (Direct-Sequence Code Division Multiple Access) is a multiple access scheme based on DSSS, by spreading the signals from/to different users with different codes. It is the most widely used type of CDMA (e.g. cell phones) 11/13/2010© 2010 Justin Richert KDØIQV12

13 Complementary Code Keying (CCK) Complementary Code Keying (CCK) is a modulation scheme used with wireless networks (WLANs) that employ the IEEE 802.11b specificationIEEE 802.11b CCK is the form of modulation utilized when 802.11b operates at either 5.5 or 11 Mbit/s. The CCK modulation used by 802.11b transmits data in symbols of eight chips, where each chip is a complex QPSK(Quadrature phase-shift key) bit- pair at a chip rate of 11Mchip/s.chipsQPSK 11/13/2010© 2010 Justin Richert KDØIQV13

14 CCK Modulation 1.M-ary Orthogonal Keying utilizing ‘polyphase complementary codes’ 2.With M-ary modulation techniques (QPSK etc), the "symbols per second" rate can be much slower than the "bits per second" data rate 3.Normally known “symbol per second rate” (BAUD rate) transmits multiple bits per baud 11/13/2010© 2010 Justin Richert KDØIQV14

15 Orthogonal Frequency Division Multiplexing (OFDM) Is a frequency-division multiplexing (FDM) scheme utilized as a digital multi-carrier modulation method A large number of closely-spaced orthogonal sub- carriers are used to carry data Sub-carriers are continuously transmitted Is NOT spread spectrum by FCC definition Each sub-carrier per channel carries part of or duplicate data Resistant to narrow band interference Requires high power CPUs and complex mathematical software processing with highly accurate clocking Cannot be built with electronic components only 11/13/2010© 2010 Justin Richert KDØIQV15

16 OFDM Modulation 11/13/2010© 2010 Justin Richert KDØIQV16

17 Orthogonal Frequency Division Multiplexing (OFDM) Uses Used in ADSL connections that follow the G.DMT (ITU G.992.1) standard, in which existing copper wires are used to achieve high-speed data connections. – For experimental amateur radio applications, users have hooked up commercial off-the-shelf ADSL equipment to radio transceivers which simply shift the bands used to the radio frequencies the user has licensed Used in wireless LAN and MAN applications, including IEEE 802.11a/g/n and WiMAX.IEEE 802.11a/g/nWiMAX Used by many powerline devices to extend Ethernet connections to other rooms in a home through its power wiring. Adaptive modulation is particularly important with such a noisy channel as electrical wiring.powerlineAdaptive modulation 11/13/2010© 2010 Justin Richert KDØIQV17

18 IEEE 802.11b (2.4GHz band) Modulation Scheme: DSSS/CCK Each “channel” is 20Mhz wide comprising 5 sub-channels with two on either side of the center channel – “Channel 6” overlaps channels 3 through 9 Capable of up to 11 Mbps Has been superseded by 802.11g for consumer applications Frequency Used is 2.402 Ghz – 2.484 Ghz Used for point to point links Still used by military applications due to security requirements – Thus FCC stringency on consumer device EIRP 11/13/2010© 2010 Justin Richert KDØIQV18

19 IEEE 802.11b/g Channel Plan Channel Center Frequency Frequency deltaChannel WidthOverlaps Channels 12.412 GHz2.401–2.423 GHz2–5 22.417 GHz5 MHz2.406–2.428 GHz1,3–6 32.422 GHz5 MHz2.411–2.433 GHz1–2,4–7 42.427 GHz5 MHz2.416–2.438 GHz1–3,5–8 52.432 GHz5 MHz2.421–2.443 GHz1–4,6–9 62.437 GHz5 MHz2.426–2.448 GHz2–5,7–10 72.442 GHz5 MHz2.431–2.453 GHz3–6,8–11 82.447 GHz5 MHz2.436–2.458 GHz4–7,9–12 92.452 GHz5 MHz2.441–2.463 GHz5–8,10–13 102.457 GHz5 MHz2.446–2.468 GHz6–9,11–13 112.462 GHz5 MHz2.451–2.473 GHz7–10,12–13 122.467 GHz5 MHz2.456–2.478 GHz8–11,13–14 132.472 GHz5 MHz2.461–2.483 GHz9–12,14 142.484 GHz12 MHz2.473–2.495 GHz12–13 11/13/2010© 2010 Justin Richert KDØIQV19

20 IEEE 802.11g (2.4GHz band) Modulation Scheme: OFDM Capable of up to 54 Mbps Used in place of 802.11b (though not as secure) Used in most corporate installations Uses Same frequency and channel plan as 802.11b Used for user access rather than point to point links Most PC’s used 802.11g by default 11/13/2010© 2010 Justin Richert KDØIQV20

21 IEEE 802.11a (5.8GHz band) Modulation Scheme: OFDM Frequency Used is 5.180 Ghz – 5.825 Ghz Capable of up to 54 Mbps Used in most corporate installations Used in most point to point links Most Mac’s including iPODs, iPADs, and iPhones by default Less cluttered frequency / More channels 11/13/2010© 2010 Justin Richert KDØIQV21

22 IEEE 802.11a Channel Plan Channel Center Frequency Channel Width 36518020 Mhz 40520020 Mhz 44522020 Mhz 48524020 Mhz 52526020 Mhz 56528020 Mhz 60530020 Mhz 64532020 Mhz 100550020 Mhz 104552020 Mhz 108554020 Mhz 112556020 Mhz 116558020 Mhz 136568020 Mhz 140570020 Mhz 149574520 Mhz 153576520 Mhz 157578520 Mhz 161580520 Mhz 165582520 Mhz 11/13/2010© 2010 Justin Richert KDØIQV22

23 12 non-overlapping 802.11a channels 20 MHz wide each 3 sets of 4 channels 4x40mw ch for indoor 4x200mw ch for indoor, outdoor 4x800mw ch for outdoor Power specified at the IR 5 GHz (802.11a) 11/13/2010© 2010 Justin Richert KDØIQV23

24 IEEE 802.11n (2.4; 3.6; 5GHz bands) 802.11n is not a new spectrum, it’s a new way of utilizing spectrum Utilizes Multiple-input multiple-output (MIMO) – MIMO is a technology which uses multiple antennas to coherently resolve more information than possible using a single antenna. 802.11n is capable of up to 600Mbps utilizing 4X4 (i.e. 4 receive antennas and 4 transmit antennas) Uses different modulation and multiplexing schemes based upon the amount of bandwidth required. 802.11n uses a 40 Mhz wide channel rather than the typical 20 Mhz wide channel Just starting to be deployed en masse 11/13/2010© 2010 Justin Richert KDØIQV24

25 IEEE 802.16 (WiMAX) Basis for Sprint / Verizon 4G Uses 16-QAM & 64-QAM Capable of up to 1Gbps in fixed Point to Point applications Capable of up to 128 Mbps in mobile applications (such as cell phones) 11/13/2010© 2010 Justin Richert KDØIQV25

26 Discussions Case Study 1: Junior High wants to do electronic curriculum. 600 Students with iPads Case Study 2: Warehouse for PDA based product scanners Case Study 3: HAM Radio Events – Providing data connectivity – ARRL HSMM Project – High Speed Multimedia with encryption & strong security protocols – D-STAR & 802.11 COTS devices (Medtronic Twin Cities Marathon) Case Study 4: Minneapolis – City Wireless Access (Wireless Meshing) Case Study 5: Missouri ARES EMCOMM – Winlink – OES (Official Emergency Stations) 11/13/2010© 2010 Justin Richert KDØIQV26


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