Objective　The　rapid　growth　of　wireless　communication　traffic　is　pushing　existing　networks　toward　greener,　more　energy-efficient　solutions.　Therefore,　research　into　wireless　communication　systems　that　balance　low　complexity　with　high　energy　efficiency　is　of　significant　importance.　Index　Modulation　(IM)　technology,　which　offers　advantages　in　low　complexity　and　high　energy　efficiency,　has　emerged　as　a　promising　candidate　for　future　systems.　Reconfigurable　Intelligent　Surfaces　(RIS)　provide　benefits　such　as　reconfigurability,　simple　hardware,　and　low　energy　consumption,　presenting　new　opportunities　for　wireless　communication　development.　However,　traditional　RIS-　aided　Spatial　Modulation　(RIS-SM)　and　RIS-aided　Code　Index　Modulation　(RIS-CIM)　systems　use　the　index　of　the　receiver　antenna　or　code　to　transmit　additional　information　bits.　Therefore,　the　data　transmission　rates　of　RIS-SM　systems　improve　at　the　cost　of　increasing　the　number　of　receiver　antennas.　To　enhance　the　data　transmission　rates　and　energy　efficiency　of　RIS-SM　systems,　this　paper　proposes　a　RIS-Aided　Joint　Spatial　and　Code　Index　Modulation　(RIS-JSCIM)　communication　system.　Methods　The　proposed　system　utilizes　M-ary　Quadrature　Amplitude　Modulation　(M-QAM)　symbols,　spatial　antenna　index,　and　code　index　to　transmit　information　bits.　The　information　bits　transmitted　through　the　antenna　and　code　indices　of　RIS-JSCIM　do　not　consume　energy,　enabling　RIS-JSCIM　to　achieve　high　energy　efficiency.　At　the　receiver,　both　Maximum　Likelihood　Detection　(MLD)　and　low-complexity　Greedy　Detection　(GD)　algorithms　are　employed.　The　MLD　algorithm,　although　high　in　complexity,　provides　excellent　Bit　Error　Rate　(BER)　performance,　while　the　GD　algorithm　offers　a　better　trade-off　between　complexity　and　BER　performance.　Furthermore,　this　paper　analyzes　the　energy　efficiency　and　complexity　of　the　proposed　RIS-JSCIM　system　and　uses　Monte　Carlo　simulations　to　evaluate　its　BER　performance.　The　performance　metrics　of　the　RIS-JSCIM　system　are　also　compared　with　those　of　other　systems.　The　results　show　that,　despite　a　slight　increase　in　system　complexity,　the　RIS-JSCIM　system　outperforms　others　in　terms　of　energy　efficiency　and　BER　performance.　Results　and　Discussions　This　paper　compares　the　energy　efficiency,　system　complexity,　and　BER　performance　of　the　RIS-JSCIM　system　with　other　systems.　The　comparison　shows　that,　when　the　number　of　receiving　antennas　NR=4　and　the　number　of　Walsh　codes　L=8,　the　energy　efficiency　of　the　RIS-JSCIM　system　improves　by　60%　and　6.67%　compared　to　the　RIS-SM　and　RIS-CIM　systems,　respectively　(Table　2).　The　complexity　of　the　RIS-JSCIM　system　with　the　GD　algorithm　is　comparable　to　that　of　the　GCIM-SM　system　and　slightly　higher　than　that　of　the　RIS-CIM　system　(Table　3).　Simulation　results　indicate　that,　at　BER=10–5,　the　RIS-JSCIM　system　achieves　a　performance　gain　of　over　6　dB　compared　to　the　RIS-CIM　system　(Fig.　5).　As　the　number　of　RIS　units　N　increases,　both　the　RIS-JSCIM　and　RIS-CIM　systems　show　significant　improvements　in　BER　performance,　with　the　RIS-JSCIM　system　outperforming　the　RIS-CIM　system　at　high　Signal-to-Noise　Ratios　(SNR).　For　example,　at　BER=10–5　and　N=128,　the　RIS-JSCIM　system　offers　a　5　dB　SNR　gain　over　the　RIS-CIM　system　(Fig.　6).　Similarly,　at　high　SNR,　the　BER　performance　of　the　RIS-JSCIM　system　consistently　outperforms　that　of　the　RIS-SM　system　(Fig.　7).　Conclusions　The　RIS-JSCIM　system　utilizes　M-QAM　symbols　to　transmit　information　bits　and　employs　the　receiver　antenna　and　code　indices　to　convey　additional　information.　Both　the　MLD　and　GD　algorithms　are　introduced　for　recovering　the　transmitted　bits.　The　MLD　algorithm　explores　all　possible　combinations　of　receiver　antenna　indices,　code　indices,　and　M-QAM　symbols,　offering　improved　BER　performance　at　the　cost　of　increased　complexity.　In　contrast,　the　GD　algorithm　performs　separate　detection　of　antenna　indices,　code　indices,　and　M-QAM　symbols,　providing　a　favorable　trade-off　between　complexity　and　BER　performance.　The　RIS-JSCIM　system　transmits　receiver　antenna　index　and　code　index　bits　without　consuming　energy,　resulting　in　high　energy　efficiency.　When　the　number　of　receiving　antennas　NR=4　and　the　number　of　Walsh　codes　L=8,　the　energy　efficiency　of　the　RIS-JSCIM　system　improves　by　60%　and　6.67%　compared　to　the　RIS-SM　and　RIS-CIM　systems,　respectively.　Moreover,　when　the　BER=10–5　and　N=128,　the　RIS-JSCIM　system　offers　a　5　dB　SNR　gain　over　the　RIS-CIM　system.　©　2025　Science　Press.　All　rights　reserved.