doc.: IEEE /0098r0 Submission November 2015 Hyunduk Kang et al, ETRISlide 1 Consideration on Neighbor Discovery Date: Authors:

doc.: IEEE /0098r0 Submission Interference vs. Neighbor discovery Interference among wireless systems is caused by wireless systems located nearby each other A first step on interference mitigation might be which wireless systems are interfering me on which channel –Interference on the same operating channel –Interference on the adjacent channel (due to partial channel overlap) Neighbor discovery let you know –Who is your neighbor that can cause co-channel or adjacent channel interference –What is further information regarding your neighbors such as network type, operating parameters, and so on. November 2015 Hyunduk Kang et al, ETRISlide 2

doc.: IEEE /0098r0 Submission Case Study: Interference vs. Neighbor Discovery among WLANs November 2015 Hyunduk Kang et al, ETRISlide 3

doc.: IEEE /0098r0 Submission Inter-BSS Interference Inter-BSS Interference (IBI) is interference among multiple basic service sets (BSSs), located nearby each other There are three types of inter-BSS interference –AP-AP IBI –AP-STA IBI –STA-STA IBI November 2015 Hyunduk Kang et al, ETRISlide 4

doc.: IEEE /0098r0 Submission Inter-BSS Interference: AP-AP It occurs when a AP receiving data from its associated STA is interfered by a neighbor AP transmitting data to its associated STA, and vice versa. November 2015 Hyunduk Kang et al, ETRISlide 5

doc.: IEEE /0098r0 Submission Inter-BSS Interference: AP-STA It occurs when a AP receiving data from its associated STA is interfered by a neighbor AP transmitting data to its associated STA, and vice versa. November 2015 Hyunduk Kang et al, ETRISlide 6

doc.: IEEE /0098r0 Submission Inter-BSS Interference: STA-STA It occurs when a STA receiving data from its associated AP is interfered by a neighbor STA transmitting data to its associated AP, and vice versa. November 2015 Hyunduk Kang et al, ETRISlide 7

doc.: IEEE /0098r0 Submission Overlapping Geography It is possible to categorize overlapping geography based on IBI classification Types of overlapping –AP-AP overlapping –BSS-BSS overlapping –STA-STA overlapping November 2015 Hyunduk Kang et al, ETRISlide 8

doc.: IEEE /0098r0 Submission AP-AP Overlapping November 2015 Hyunduk Kang et al, ETRISlide 9 AP1 and AP2 directly can hear each other APs and STAs might suffer from –AP-AP IBI –AP-STA IBI –STA-STA IBI

doc.: IEEE /0098r0 Submission BSS-BSS Overlapping November 2015 Hyunduk Kang et al, ETRISlide 10 AP1 and AP2 directly can NOT hear each other APs and STAs might suffer from –AP-STA IBI –STA-STA IBI

doc.: IEEE /0098r0 Submission STA-STA Overlapping November 2015 Hyunduk Kang et al, ETRISlide 11 AP1 and AP2 directly can NOT hear each other STAs might suffer from –STA-STA IBI

doc.: IEEE /0098r0 Submission No Overlapping: BSS-BSS Separation November 2015 Hyunduk Kang et al, ETRISlide 12 There is no interference between BSSs Ideal spatial reuse is possible

doc.: IEEE /0098r0 Submission Comparison among Types of Overlap November 2015 Hyunduk Kang et al, ETRISlide 13 Type of overlapping Inter-BSS interference: AP-AP Inter-BSS interference: AP-STA Inter-BSS interference: STA-STA Amount of Inter-BSS interference Hidden neighbor AP AP-APYES Heavy- BSS-BSS-YES MediumYES STA-STA--YESLightYES No----- AP-AP could get lot of co-channel interference. However, it might be favorable to mitigate interference since AP can hear each other directly BSS-BSS seems to difficult to mitigate co-channel interference since APs are blinded each other

doc.: IEEE /0098r0 Submission Existing Mechanisms for Neighbor Discovery on WLANs Spectrum sensing –CCA-ED (for other wireless system) –CCA-SD (for WLANs, preamble detection is possible) Passive scanning –Beacon listening Active scanning –Probe request/response Virtual carrier sensing –RTS/CTS BSS color: ah-D2.0 Neighbor report Reduced neighbor report: af-2012 Radio measurement November 2015 Hyunduk Kang et al, ETRISlide 14

doc.: IEEE /0098r0 Submission Possible Mechanisms for Neighbor Discovery among Wireless Systems November 2015 Hyunduk Kang et al, ETRISlide 15

doc.: IEEE /0098r0 Submission Spectrum sensing (or radio measurement) Each wireless systems perform it by itself In general, two methods are –Energy detection (to reveal existence of other wireless systems) ED Threshold adjustment is one of important issues to deal with –Feature detection (to identity type of other wireless systems) Decode preamble information of other wireless systems Obtain more information based on preamble data November 2015 Hyunduk Kang et al, ETRISlide 16

doc.: IEEE /0098r0 Submission Message exchanging Neighbor information could be exchanged –Via wireless channel –Via wired channel Neighbor information could be exchanged –By directly among neighbors –By indirectly using external entities Neighbor information could be obtained by combinations of –Results of spectrum sensing (or radio measurement) by each wireless systems –Geo-location information if available November 2015 Hyunduk Kang et al, ETRISlide 17

doc.: IEEE /0098r0 Submission Concluding Remarks Neighbor discovery is the very first step for interference mitigation for better coexistence among wireless systems Neighbor discovery among dissimilar wireless systems might be more difficult than that among similar wireless systems –Just to reveal existence of neighbor is not enough for interference mitigation. –The more information on neighbor, the better coexistence among neighbor –How/What to exchange among neighbor is one of important issues November 2015 Hyunduk Kang et al, ETRISlide 18