Wireless site survey
A wireless site survey, sometimes called an RF site survey or wireless survey, is the process of planning and designing a wireless network, to provide a wireless solution that will deliver the required wireless coverage, data rates, network capacity, roaming capability and Quality of Service (QoS).[1] The survey usually involves a site visit to test for RF interference, and to identify optimum installation locations for access points. This requires analysis of building floor plans, inspection of the facility, and use of site survey tools. Interviews with IT management and the end users of the wireless network are also important to determine the design parameters for the wireless network.
As part of the wireless site survey, the effective range boundary is set, which defines the area over which signal levels needed support the intended application. This involves determining the minimum signal to noise ratio (SNR) needed to support performance requirements.
Independent studies have shown that most of the Wi-Fi wireless networks installed today are not optimally designed or installed,[citation needed] and many do not provide the service that they were intended to. Because of this, stringent wireless site surveys, planning and design exercises are becoming essential, especially to support the new breed of wireless services such as Mobile VoIP and real-time location-based service.
Wireless site survey can also mean the walk-testing, auditing, analysis or diagnosis of an existing wireless network, particularly one which is not providing the level of service required.[1]
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[edit] Wireless site survey software
Wireless site surveys are typically conducted using computer software that collects and analyses WLAN metrics and/or RF spectrum characteristics. Before a survey, a floor plan or site map is imported into a site survey application and calibrated to set scale. During a survey, a surveyor walks the facility with a portable computer that continuously records the data. The surveyor either marks the current position on the floor plan manually, by clicking on the floor plan, or uses a GPS receiver that automatically marks the current position if the survey is conducted outdoors. After a survey, data analysis is performed and survey results are documented in site survey reports generated by the application.
All these data collection, analysis, and visualization tasks are highly automated in modern software. In the past, however, these tasks required manual data recording and processing .[2][3]
[edit] Notable site survey applications
Currently, professional-level site survey applications exist primarily for Microsoft Windows. Notable applications include: [4][5][6][7]
- AirMagnet Survey by AirMagnet
- Ekahau Site Survey by Ekahau
- TamoGraph Site Survey by TamoSoft
- Visiwave Site Survey by AZO Technologies
- WaveDeploy by Ixia (formerly VeriWave)
Some site survey applications for other platforms, including iOS and Android, also exist, however they are limited in functionality due to the limitations of the underlying platform API. For example, signal level measurements cannot be obtained on iOS without jailbreaking[8]. The feasibility of creating professional-level applications for non-Windows tablets is debated.[9][10]
[edit] Types of wireless site surveys
There are three main types of wireless site surveys: passive, active, and predictive.
During a passive survey, a site survey application passively listens to WLAN traffic to detect active access points, measure signal strength and noise level. However, the wireless adapter being used for a survey is not associated to any WLANs.
During an active survey, the wireless adapter is associated with one or several access points to measure round-trip time, throughput rates, packet loss, and retransmissions.
During a predictive survey, a model of the RF environment is created using simulation tools. Virtual access points are then placed on the floor plan to estimate expected coverage and adjust their number and location.
Additionally, some survey application allow the user to collect RF spectrum data using portable hardware spectrum analyzers, which is beneficial in case of high RF interference from non-802.11 sources, such as microwave ovens or cordless phones.[11][12]
[edit] References
- ^ a b Joshua Bardwell; Devin Akin (2005). Certified Wireless Network Administrator Official Study Guide (Third ed.). McGraw-Hill. pp. 479-547. ISBN 978-0072255386. http://books.google.com/books?id=QnMunBGVDuMC&printsec=frontcover&dq=cwna+official+study+guide&hl=en&ei=EJaXTpSaFMPSiALTu4HCDQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAA#v=onepage&q&f=false.
- ^ "Wireless Site Survey FAQ". http://www.cisco.com/en/US/tech/tk722/tk809/technologies_q_and_a_item09186a00805e9a96.shtml. Retrieved 2012-01-12.
- ^ "Performing a Site Survey". http://www.cisco.com/en/US/docs/wireless/wlan_adapter/cb21ag/user/2.0/configuration/guide/winapFkh.html. Retrieved 2012-01-12.
- ^ "Veriwave WaveDeploy: A New Way To Site Survey". http://www.networkcomputing.com/wireless/229501638. Retrieved 2012-01-12.
- ^ "TamoSoft Wi-Fi Tools Worth Looking At". http://www.networkcomputing.com/wireless/229500228. Retrieved 2012-01-12.
- ^ "Wireless security tools". http://wirelesslanprofessionals.com/wlw038-wlan-hardware-software-options/. Retrieved 2012-01-12.
- ^ "WLAN Hardware & Software Options". http://www.corecom.com/html/wlan_tools.html. Retrieved 2012-01-12.
- ^ "Apple Bans Wi-Fi Stumbler iPhone Apps – Blames Use Of Private APIs". http://www.iphonehacks.com/2010/03/apple-bans-wifi-stumbler-iphone-apps-blames-use-of-private-apis.html. Retrieved 2012-01-12.
- ^ "Argument Against Using iPad for WiFi Surveys". http://wlanbook.com/argument-against-using-ipad-for-wifi-surveys/. Retrieved 2012-01-12.
- ^ "Site survey for iPad users". http://www.cwnp.com/bbpress/topic.php?id=6811. Retrieved 2012-01-12.
- ^ "Automated 802.11 Spectrum Analysis/Remediation: Benefits And Implications". http://www.networkcomputing.com/next-gen-network/229501644. Retrieved 2012-01-12.
- ^ "Analyze this: Low-cost wireless spectrum analyzers do the trick". http://www.networkworld.com/reviews/2009/032309-wlan-test.html. Retrieved 2012-01-12.
