In　this　paper,　we　propose　a　polarization-aided　detection　and　decoding　scheme　for　polar-coded　multi-user　spatial　modulation　(PA-MU-SM)　systems.　Exploiting　the　polar　code　structure,　we　treat　the　reception　processing　in　MU-SM　as　a　polar　re-encoding　that　generates　an　extended-length　polar　code　with　nested　user　codes.　The　proposed　method　enables　us　to　decode　all　user　messages　within　this　single　polar　decoder.　Then,　a　Monte-Carlo　construction　is　utilized　to　optimize　the　nested　user　codes　of　the　extended-length　polar　code.　Furthermore,　to　eliminate　the　interference　between　user　layers　of　the　PA-MU-SM,　an　iterative　polarization-aided　(I-PA)　scheme　is　designed　and　can　theoretically　achieve　MU-SM　channel　capacity　via　a　four-stage　channel　transform.　Simulation　results　show　that　the　proposed　PA　and　I-PA　schemes　offer　better　error　performance　than　the　traditional　polar-coded　spatial　modulation　(PC-SM)　schemes.　©　1967-2012　IEEE.