In　this　letter,　a　joint　pulse　position　modulation　(PPM)　and　permutation　index　differential　chaos　shift　keying　(PI-DCSK)　modulation　scheme　(PPM-PI-DCSK)　is　proposed　to　increase　the　data　rate　and　improve　performance.　In　PPM-PI-DCSK,　the　bit　stream　is　divided　into　blocks　of　m　p　+　m　c　+1　bits,　where　m　p　bits　are　modulated　by　PPM,　m　c　bits　are　modulated　by　PI　modulation,　and　the　last　one　bit　is　modulated　by　DCSK.　The　theoretical　bit　error　rate　(BER)　performance　of　the　proposed　PPM-PI-DCSK　is　derived　over　multipath　Rayleigh　fading　channels　and　validated　via　simulations.　Simulation　results　show　that　the　proposed　PPM-PI-DCSK　outperforms　the　benchmark　DCSK-based　schemes.　Furthermore,　the　performance　superiority　is　also　demonstrated　by　the　frequency-modulated　PPM-PI-DCSK　over　a　typical　ultra-wideband　(UWB)　channel.　This　demonstrates　the　superiority　and　feasibility　of　the　proposed　scheme　in　practical　applications.　©　2012　IEEE.