There is no standardized relationship of any particular physical parameter to the RSSI reading. The 802.11 standard does not define any relationship between RSSI value and power level in [[milliwatts]] or [[dBm|decibels referenced to one milliwatt (dBm)]]. Vendors and chipset makers provide their own accuracy, granularity, and range for the actual power (measured as milliwatts or decibels) and their range of RSSI values (from 0 to RSSI maximum).<ref>{{cite conference|last1=Lui|first1=Gough|last2=Gallagher|first2=Thomas|last3=Binghao|first3=Li|conference=2011 International Conference on Localization and GNSS (ICL-GNSS)|title=Differences in RSSI readings made by different Wi-Fi chipsets: A limitation of WLAN localization|pages=53–57|doi=10.1109/ICL-GNSS.2011.5955283|isbn=978-1-4577-0186-3|year=2011|s2cid=16846238}}</ref> One subtlety of the 802.11 RSSI metric comes from how it is sampled{{mdash}}RSSI is acquired during only the preamble stage of receiving an 802.11 frame, not over the full frame.<ref name=":0" />
As early as 2000, researchers were able to use RSSI for coarse-grained ___location estimates.<ref name=bahl-infocom2000>{{cite webconference|last1=Paramvir|first1=Bahl|last2=Padmanabhan|first2=Venkata|title=RADAR: An In-Building RF-based User Location and Tracking System|url=httphttps://researchwww.microsoft.com/en-us/peopleresearch/padmanabpublication/infocom2000radar-an-in-building-rf-based-user-___location-and-tracking-system/|book-title=Proceedings IEEE INFOCOM 2000.pdf Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies|workdoi=10.1109/INFCOM.2000.832252|accessdateaccess-date=19 December 2014}}</ref> More recent work was able to reproduce these results using more advanced techniques.<ref name="sev-mobisys2013">{{cite conference|last1 = Sen|first1 = Souvik|last2 = Lee|first2 = Jeongkeun|last3 = Kim|first3 = Kyu-Han|last4 = Congdon|first4 = Paul|title = Avoiding Multipath to Revive Inbuilding WiFi Localization|url = http://dl.acm.org/citation.cfm?id=2464463|book-title = MobiSys '13: Proceeding of the 11th annual international conference on Mobile systems, applications, and services | year=2013 | pages=249-262 | doi=10.1145/2462456.2464463 | isbn=9781450316729 | s2cid=16251944 |accessdate = 19 December 2014}}</ref> Nevertheless, RSSI does not always provide measurements that are sufficiently accurate to properly determine the ___location.<ref name=parameswaran-srds2009>{{cite conference|last1=Parameswaran|first1=Ambili Thottam|last2=Husain|first2= M, I.|last3= Upadhyaya|first3= S. |title=Is RSSI a Reliable Parameter in Sensor Localization Algorithms – An Experimental Study|url=http://www.cse.buffalo.edu/srds2009/F2DA/f2da09_RSSI_Parameswaran.pdf|work=September 2009|conference=28th International Symposium On Reliable Distributed Systems, New York|access-date=17 March 2013}}</ref> However, RSSI still represents the most feasible indicator for localization purposes as it is available in almost all wireless nodes and it does not have any additional hardware requirements.<ref name=abdullah2016>{{cite journal|url=https://www.researchgate.net/publication/309257981 |last1=Alhasanat|first1=Abdullah|last2=Sharif|first2= Bayan |last3= Tsemendis|first3= C. |title=Efficient RSS-based collaborative localisation in wireless sensor networks|date=January 2016 |journal=International Journal of Sensor Networks |volume=22 |issue=1 |pages=27-36 |doi=10.1504/IJSNET.2016.079335}}</ref>
