Multi antenna technology can improve the spectrum efficiency of wireless re-sources and improve the quality of communication under the condition of no additional power and bandwidth.In this paper,a multi user MIMO downlink space division multiple access( SDMA) algorithm is proposed,which is suitable for indoor distributed system sce-narios.First,ratio of the signal power to interference power was computed by measuring the power of different users in different channel.And then,a preliminary decision of whether to use SDMA was done according to the ratio. Finally,SDMA interference compensation w...