Fundamental Performance Limits on Time of Arrival Estimation Accuracy with 5G Radio Access

5G radio access technology stimulates new use cases and emerging businessmodels, evolving the world to become a fully mobile and connected networksociety, expected to be operational by 2020. To enable ultra-high reliable andhighly precise features, there are more stringent positioning accuracy requirementsfor location based services and E911 emergency calls, targeting at bothindoor and outdoor users which include humans, devices, vehicles and machines.In currently deployed Long Term Evolution (LTE) networks, Observed TimeDi↵erence of Arrival (OTDoA) positioning is acting as one of the User Equipment(UE) localization techniques. The positioning accuracy in OTDoA methoddepends on various factors, e.g. network deployment, signal propagation conditionand properties of Positioning Reference Signal (PRS). For a given deploymentand propagation scenario, significant improvements of positioning accuracyis achievable by appropriately redesigning the PRS with 5G radio access.In this thesis, fundamental performance limits (i.e. Cramer Rao Lower Bounds)on Time of Arrival (ToA) estimation are derived respectively considering frequencyselective channel with additive white noise, carrier frequency o↵set andWiener phase noise. Particularly, the e↵ects of flexible bandwidth, subcarrierspacing and power allocation on ToA estimation accuracy have been investigatedin di↵erent settings based on corresponding performance bounds. Furthermore,the performance limits on ToA estimation can be translated into UE positioningaccuracy for a given deployment scenario. Overall, the thesis has built valuableinsights on PRS design and waveform optimization for 5G based positioning.5G radioteknik stimulerar nya anv¨andaromr°aden och nya a↵¨arsmodeller samtutvecklar v¨arlden till att bli ett helt mobilt och anslutet n¨atverkssamh¨alle,vilket f¨orv¨antas vara i drift till °ar 2020. F¨or att m¨ojligg¨ora ultrah¨og p°alitlighetoch h¨ogprecisionsfunktionalitet kr¨avs det str¨angare krav p°a positionering f¨orplatsbaserade tj¨anster och n¨odsamtal, som riktar in sig p°a b°ade inomhus- ochutomhusanv¨andare vilket inkluderar m¨anniskor, enheter, fordon och maskiner.I det nuvarande distribuerade LTE-n¨atverket fungerar Observed Time Di↵erenceof Arrival-positionering (OTDoA)-positionering som en av lokaliseringsteknikernaf¨or anv¨andarutrustning (UE). Positioneringsnoggrannheten i OTDoAmetodenberor p°a olika faktorer, t.ex. n¨atverksutbyggnad, signalutbredningsf¨orh°allande och egenskaper f¨or positions referenssignal (PRS). F¨or ett visstinstallations- och utbredningsscenario kan betydande f¨orb¨attringar av positionsnoggrannhetenuppn°as genom att omforma PRS p°a l¨ampligt s¨att.I detta examensarbetet unders¨oks de grundl¨aggande prestandabegr¨ansningarna(dvs Cramer Rao Lower Bounds) vid Ankomsttid (ToA) h¨arl¨adda med avseendep°a frekvensselektiva kanaler med additivt vitt brus, b¨arfrekvensf¨orskjutning ochWienerfasbrus. I synnerhet, unders¨oks e↵ekten av flexibel bandbredd, subcarrieravst°and och e↵ektallokering p°a ToA-estimeringsnoggrannhet unders¨okts iolika inst¨allningar baserat p°a prestandabegr¨ansningarna. Vidare kan prestandabegr¨ansningarna f¨or ToA-estimering ¨overs¨attas till UE-positionsnoggrannhetf¨or ett givet implementationsscenario. Slutligen s°a har detta examensarbetetgett viktiga insikter om positionering av referenssignaldesign och v°agformsoptimeringf¨or 5G-baserad positionering