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Si t e Survey Fundament alsSi t e Survey Fundament als
Chapt er 9Chapt er 9
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What is a Si t e Sur vey?What is a Si t e Sur vey?
z An RF site survey is a map to successfully
im plem ent ing a w ireless net w ork.
z
A site survey is the most important step inim plem ent ing any w ir eless net w ork.
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Prepar ing f or a Si t e SurveyPrepar ing f or a Si t e Survey
z Facil i t ies Analysis
z Purpose & Business Requi rem ent s
z Bandw id t h & Roam ing Requir ement s
z Available Resourcesz Exist ing Net w orks
z
Area Usage & Tow ers
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Facil i t y AnalysisFacil i t y Analysis
z What kind of faci l i t y is i t ?
z Consider the obvious differences that
would exist in conducting a site survey of asmall off ice with versus performing a si tesurvey of a large of f ice.
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Exist ing Net w orksExist ing Net w orks
z Is t here already a
network (wired orwireless) in place?
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Area Usage & Tow ersArea Usage & Tow ers
z Is t he wireless LAN
going t o be usedindoors, outdoors, orboth?
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Purpose & Business RequirementsPurpose & Business Requirements
z What is t he purpose of t he wireless LAN?
z What are the business requirements?
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Bandwidth & Roaming RequirementsBandwidth & Roaming Requirements
z What bandwidth and
roaming requirementsare there?
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5. 5 Mbps dat a rat e5. 5 Mbps dat a rat e
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Roam ing Requi rem ent sRoam ing Requi rem ent s
z How many users are t ypical ly in a given
area?z What t ype of appl icat ions wil l be used over
t he wireless LAN?
z Are t here any non-t ypical t imes in whichnet work needs may change for a part iculararea?
z What mobil i t y or roaming coverage isnecessary?
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Avai lable ResourcesAvai lable Resources
z What are t he available resources?
z Are facility blueprints available (electronicor print ed)?
z Are t here any previous sit e survey report s
available?z Is a facil i t ies escort or securit y badge
required?
z Is physical access t o wiring closets and t heroof available if needed?
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Security RequirementsSecurity Requirements
z What level of network security is
necessary?z What corporat e pol icies are in place
regarding wireless LAN securit yimplement at ion and management ?
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Preparation ChecklistPreparation Checklistz Bui lding blueprint s
z Previous w ir eless LAN sit e survey docum ent at ion
z Current net w ork diagram
z A meet ing wi th the network admin is t ra tor , the bu i ld ingmanager, t he secur i t y of f icer .
z
Access to al l areas of the faci l i ty to be affected by thew i rel ess LAN
z Access t o w ir ing closet s
z Access t o roof ( i f out door ant ennas are ant icipat ed)
z Future construction plans, i f avai lable.
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Site Survey EquipmentSite Survey Equipment
z Access Point
z PC Card and Ut i l i t iesz Lapt ops & PDAs
z Paper
z Outdoor Surveys
z Spect rum Analyzer
z Net w ork Analyzerz Si t e Survey Ki t Checkl ist
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Access PointAccess Point
z Used during a site survey should have
vari able out put power and ext ernal ant ennaconnectors.
z The var iable output power feature a l lowsfor easy sizing of coverage cells during the
si t e survey.
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PC Card and Ut i l i t iesPC Card and Ut i l i t ies
z Signal st rengt h (m easured i n dBm)
z Noise f loor (m easured in dBm)
z Signal- t o-noise rat io ( SNR ) (measured in
dB)z Link speed
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Laptops &Laptops & PDAsPDAs
z A laptop computer or PDA unit is used by
the site surveyor for checking for signalstrength and coverage while roamingaround t he f ac i l i t y.
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Out door SurveysOut door Surveys
z Outdoor si te surveys wi l l take more t ime,
ef for t , and equipment than wi l l indoorsurveys
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Spect rum AnalyzerSpect rum Analyzer
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Net w ork AnalyzerNet w ork Analyzer
z Pick up any
packet s beingt ransmi t t ed bywireless LANsand wi l l
providedetai ledinf ormat ion onchannel s inuse, di st ance,and signalstrength.
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Si t e Survey Ki t Checkl istSi t e Survey Ki t Checkl istz Lapt op and/ or PDA included sit e survey ut i l i t y soft w arez Wirel ess PC card wi t h dr i ver & ut i l i t y sof t ware
z Access poi nt s or br idges as neededz Bat t ery pack & DC-t o-AC convert erz Clipboard, pen, penci ls, notebook paper, gr id paper, & hi- l i t erz Bluepr int s & net w ork diagramsz Indoor & outdoor ant ennasz Cables & connect orsz Binoculars and t w o-way r adiosz Umbr el la and/ or rain sui tz Specialized software or hardware such as a spectrum analyzer or
snif ferz Tools, double-sided tape, and other i tems for temporary hardware
mount ingsz Secure & padded equipment case for housing computers, tools,
secure documents dur ing the survey and travel to and from the
survey sit e
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Conduct ing a Si t e SurveyConduct ing a Si t e Survey
z Indoor Surveys
z Outdoor Surveys
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RF Inf orm at ion Gat her ingRF Inf orm at ion Gat her ingz Range & coverage pat t erns
z
Dat a rat e boundar iesz Documentat ion
z Throughput t est s & capaci t y planning
z
In t er ference sourcesz Wired dat a connect ivi t y & AC pow erc requ irement s
z Out door ant enna p lacement
z
Spot checks
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Range and Coverage Pat t ernsRange and Coverage Pat t erns
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Marked up f l oor planMarked up f l oor plan
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Dat a Rat e Boundar iesDat a Rat e Boundar ies
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Int er f erence SourcesInt er f erence Sourcesz Are there any exist ing wireless LANs in use in or
near t he faci l i t y?z Are t here any plans for future wireless LAN
inst al lat ions other t han t he one in quest ion?
If t his is a mult i-tenant building, aret here any ot herorganizat ions wit hin
t he building t hathave wireless LANs orsources of RF? Are anyot her organizat ions
planning wireless LANimplementations?
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Int er f erence SourcesInt er f erence Sources
z Are there any ot her common sources of RF
int erference in t he 2.4 GHz band in use int he facil i t y?
z In case 802.11a net works are to be
inst al led, are t here any RF sources in the 5GHz range?
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ObstacleObstacle -- Induced Signal LossInduced Signal Loss
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Spot ChecksSpot Checks
z Coverage in per im et er areas
z Over lapping coverage f or seamless roaming
z Co-channel and adjacent channel
int erf erence in al l areas
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Si t e Survey Repor t ingSi t e Survey Repor t ingz Report Format
z
Purpose and Business Requirementsz Methodology
z RF Coverage Areas
z Throughputz Interference
z Problem Areas
z Drawings
z Hardware placement & configurationinformation