Editing Mobile computing (section)

==Mobile data communication==
[[Wireless]] data connections used in mobile computing take three general forms.<ref name="Ositech">{{Cite web|title=Wireless Data Communications for Beginners|url=http://www.ositech.com/downloads/123dwnlod_1.html|url-status=dead|archive-url=https://web.archive.org/web/20110713084232/http://www.ositech.com/downloads/123dwnlod_1.html|archive-date=2011-07-13|access-date=2011-07-12|publisher=Ositech Communications}}</ref> [[Cellular network|Cellular]] data service uses technologies [[GSM]], [[code-division multiple access|CDMA]] or [[General Packet Radio Service|GPRS]], [[3G]] networks such as [[W-CDMA]], [[Enhanced Data Rates for GSM Evolution|EDGE]] or [[CDMA2000]].<ref>Lachu Aravamudhan, Stefano Faccin, Risto Mononen, Basavaraj Patil, Yousuf Saifullah, Sarvesh Sharma, Srinivas Sreemanthula. [http://www.informit.com/articles/printerfriendly.aspx?p=98132 "Getting to Know Wireless Networks and Technology"] {{Webarchive|url=https://web.archive.org/web/20131004200150/http://www.informit.com/articles/printerfriendly.aspx?p=98132 |date=2013-10-04 }}, ''InformIT''<!--accessed July 12, 2011--></ref><ref>[http://www.itu.int/ITU-D/imt-2000/DocumentsIMT2000/What_really_3G.pdf "What really is a Third Generation (3G) Mobile Technology"] {{webarchive|url=https://web.archive.org/web/20110607105523/http://www.itu.int/ITU-D/imt-2000/DocumentsIMT2000/What_really_3G.pdf |date=2011-06-07 }}, ''ITU''<!--accessed July 12, 2011--></ref> and more recently [[4G]] and [[5G]] networks.  These networks are usually available within range of commercial [[Cell site|cell towers]].  [[Wi-Fi]] connections offer higher performance,<ref>Gier, Jim. [http://www.wireless-nets.com/resources/downloads/wireless_industry_report_2007.pdf "Wireless Network Industry Report"] {{Webarchive|url=https://web.archive.org/web/20121012152324/http://www.wireless-nets.com/resources/downloads/wireless_industry_report_2007.pdf |date=2012-10-12 }}, ''Wireless Nets, Ltd.''<!--accessed July 12, 2011--></ref> may be either on a private business network or accessed through public [[Hotspot (Wi-Fi)|hotspots]], and have a typical range of 100 feet indoors and up to 1000 feet outdoors.<ref>[http://www.hotrecruiter.com/resources/technical-tutorials/35-freelance-tips-a-tutorials/893-wi-fi "Wi-Fi"] {{Webarchive|url=https://web.archive.org/web/20120327014110/http://www.hotrecruiter.com/resources/technical-tutorials/35-freelance-tips-a-tutorials/893-wi-fi |date=2012-03-27 }} <!--accessed July 12, 2011--></ref> [[Satellite Internet access]] covers areas where cellular and Wi-Fi are not available<ref>{{cite web|last =Mitchell|first = Bradley|website = about.com|url =http://compnetworking.about.com/od/internetaccessbestuses/g/bldef_satellite.htm|title =Satellite Internet|archiveurl = https://web.archive.org/web/20110726110741/http://compnetworking.about.com/od/internetaccessbestuses/g/bldef_satellite.htm|archivedate = 26 July 2011}}</ref> and may be set up anywhere the user has a [[Line-of-sight propagation|line of sight]] to the satellite's location,<ref>[http://www.compassroseintl.com/pubs/Intro_to_sats.html "Introduction to Global Satellite Systems"] {{Webarchive|url=https://web.archive.org/web/20111023204753/http://www.compassroseintl.com/pubs/Intro_to_sats.html |date=2011-10-23 }}, ''CompassRose International Publications''<!--accessed July 12, 2011--></ref> which for satellites in [[geostationary]] orbit means having an unobstructed view of the southern sky.<ref name="Ositech" /> Some enterprise deployments combine networks from multiple cellular networks or use a mix of cellular, Wi-Fi and satellite.<ref>[http://www.netmotionwireless.com/resources/case_studies.aspx Case studies] {{webarchive|url=https://web.archive.org/web/20120331081316/http://www1.netmotionwireless.com/resources/case_studies.aspx |date=2012-03-31 }}, ''netmotionwireless.com''<!--accessed July 12, 2011--></ref> When using a mix of networks, a [[mobile virtual private network]] ([[mobile virtual private network|mobile VPN]]) not only handles the [[Computer security|security]] concerns, but also performs the multiple network [[login]]s automatically and keeps the [[Application software |application]] connections alive to prevent [[Crash (computing)|crashes]] or data loss during network transitions or coverage loss.<ref>Phifer, Lisa. [http://searchmobilecomputing.techtarget.com/tip/0,289483,sid40_gci1210989_mem1,00.html "Mobile VPN: Closing the Gap"] {{Webarchive|url=https://web.archive.org/web/20200706084816/https://searchmobilecomputing.techtarget.com/tip/Mobile-VPN-Closing-the-gap |date=2020-07-06 }}, ''SearchMobileComputing.com'', July 16, 2006. <!--accessed July 12, 2011--></ref><ref name="Cheng">Cheng, Roger. [https://www.wsj.com/articles/SB119717610996418467 "Lost Connections"] {{Webarchive|url=https://web.archive.org/web/20180328101055/https://www.wsj.com/articles/SB119717610996418467 |date=2018-03-28 }}, ''[[The Wall Street Journal]]'', December 11, 2007. <!--accessed July 12, 2011--></ref>