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

Why-Fi

A HAM Radio & 802.11 b/g/a/n Presentation

Fixed Infrastructure11/13/2010 © 2010 Justin Richert KDØIQV 1

Introduction

AgendaSafety FirstFCC RulesModulation AlgorithmsIndustry StandardsFun Stuff

11/13/2010 © 2010 Justin Richert KDØIQV 2

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)


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 KDØIQV 4

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 directional 29 dBm (800 mW) 9 6.35

28 dBm (640 mW) 12 10.14

27 dBM (500 mW) 15 15.81

26 dBm (400 mW) 18 25.23

25 dBm (320 mW) 21 40.28

24 dBm (250 mW) 24 62.79

23 dBm (200 mW) 27 100.2

22 dBm (160 mW) 30 160.0

• 2.4 Ghz

Note transmitter power decrease as antenna gain increases - spec 1 Watt (+30dbm), through 6dbi omni-directional antenna for 36dbm per system


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 GHzomni-directional 16 dBm (40 mW) 6 0.16

5.25-5.35 GHzomni-directional 23 dBm (200 mW) 6 0.80

5.725-5.825 GHz omni-directional 30 dBm (1 W) 6 3.98 (36dbm)

5.725-5.825 GHz directional 30 dBm (1 W) 28 630.9


HAM FCC Part 97 RulesNote: 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.


2.4GHz 802.11b/g channels

HAM ALLOCATION

23

90

24

10

24

30

24

00

24

20

24

40

24

50

24

60

25

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24

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24

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24

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802.11b STANDARD FREQS

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5 -

24

32

CH

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42

CH

9 -

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52

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CH

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HAM FCC Part 97 RulesAmateur Radio regulated by transmitter power with use

of any antenna design of any gainAchievable under Part 97: Max. PEP RF power Ant. gain EIRP*

900 MHz (spread spectrum) 10 watts 14 dBd yagi

(16.1dbi) 411.9 watts

2.4 GHz (spread spectrum i.e. 802.11 or 802.11b)

10 watts 24 dBi partial parabolic 2511.89 watts

2.4 GHz (non spread spectrum i.e. 802.11g)

1500 watts (per 97.313)

24 dBi partial parabolic 376.8 Kilo-watts

5.7 GHz (non spread spectrum i.e. 802.11a)

1500 watts (per 97.313) 28 dBi dish 946.4 Kilo-watts


http://www.qsl.net/kb9mwr/projects/wireless/allocations.html#802.11

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


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


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)


Complementary Code Keying (CCK)

• Complementary Code Keying (CCK) is a modulation scheme used with wireless networks (WLANs) that employ the IEEE 802.11b specification

• 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.


CCK Modulation1. 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


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


OFDM Modulation


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.

• 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.


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


IEEE 802.11b/g

• Channel Plan

Channel Center Frequency Frequency delta Channel Width Overlaps Channels

1 2.412 GHz 2.401–2.423 GHz 2–5

2 2.417 GHz 5 MHz 2.406–2.428 GHz 1,3–6

3 2.422 GHz 5 MHz 2.411–2.433 GHz 1–2,4–7

4 2.427 GHz 5 MHz 2.416–2.438 GHz 1–3,5–8

5 2.432 GHz 5 MHz 2.421–2.443 GHz 1–4,6–9

6 2.437 GHz 5 MHz 2.426–2.448 GHz 2–5,7–10

7 2.442 GHz 5 MHz 2.431–2.453 GHz 3–6,8–11

8 2.447 GHz 5 MHz 2.436–2.458 GHz 4–7,9–12

9 2.452 GHz 5 MHz 2.441–2.463 GHz 5–8,10–13

10 2.457 GHz 5 MHz 2.446–2.468 GHz 6–9,11–13

11 2.462 GHz 5 MHz 2.451–2.473 GHz 7–10,12–13

12 2.467 GHz 5 MHz 2.456–2.478 GHz 8–11,13–14

13 2.472 GHz 5 MHz 2.461–2.483 GHz 9–12,14

14 2.484 GHz 12 MHz 2.473–2.495 GHz 12–13


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


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


IEEE 802.11a• Channel Plan

Channel Center Frequency Channel Width

36 5180 20 Mhz

40 5200 20 Mhz

44 5220 20 Mhz

48 5240 20 Mhz

52 5260 20 Mhz

56 5280 20 Mhz

60 5300 20 Mhz

64 5320 20 Mhz

100 5500 20 Mhz

104 5520 20 Mhz

108 5540 20 Mhz

112 5560 20 Mhz

116 5580 20 Mhz

136 5680 20 Mhz

140 5700 20 Mhz

149 5745 20 Mhz

153 5765 20 Mhz

157 5785 20 Mhz

161 5805 20 Mhz

165 5825 20 Mhz11/13/2010 © 2010 Justin Richert KDØIQV 22

• 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

802.11a Standard Frequencies

5745

5765

5785

5805

U-NIIUpper Band

(800mw max)

5180

5220

5200

5240

U-NIILower Band(40mw max)

5260

5280

5300

5320

U-NIIMiddle Band(200mw max)

5470 - 5725 MHzProposed additional U-NII Spectrum

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fied

5650

- 5

925

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5760

.3 -

576

0.4

5150

5250

5350

5450

5550

5650

5725

5825

5925

Ham Allocation

5 GHz (802.11a)


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


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)


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)


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

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