To　mitigate　the　effect　of　multipath　components　on　ranging　performance,　we　investigate　a　new　joint　communication-and-localization　system　based　on　DCSK-UWB　technique.　In　particular,　we　put　forward　a　feedback　variance-detection-based　time　of　arrival　(FVD-ToA)　estimator　for　the　DCSK-UWB　system.　Furthermore,　we　derive　the　Crammer-Rao　lower　bound　(CRLB)　and　Ziv-Zakai　lower　bound　(ZZLB)　for　the　proposed　DCSK-UWB-aided　joint　communication-and-localization　system　over　IEEE　802.15.4a　channel　models.　Simulation　results　illustrate　that　the　proposed　FVD-ToA　estimator　outperforms　its　non-feedback　counterpart　and　the　traditional　energy-detection-based　(ED)　ToA　estimator.　In　consequence,　the　proposed　framework　has　desirable　potential　for　the　Internet-of-Things　(IoT)-enabled　joint　communication-and-localization　applications.　©　2022　IEEE.