Comprehensive study on novel Linear-Dispersion Division Multiple-Access(LDDMA) for multi-user uplink Multiple-Input Multiple-Output(MIMO)systems is proposed.In the new multi-plexing scheme,each user’s information symbol is dispersed by a User-Specific Matrix(USM)both inspace and time domain and linearly combined at base-station side.And a simple random search al-gorithm,based on capacity maximization criteria,is developed to generate a bank of USMs.Simulationresults are presented to demonstrate the advantages of LDDMA.When the Bit Error Rate(BER)reaches 10–3,the performance gains are 3dB and 5dB,compared with Time-Division Linear DispersionCodes(TD-LDC)and BLAST,respectively. Comprehensive study on novel Linear-Dispersion Division Multiple-Access (LDDMA) for multi-user uplink Multiple-Input Multiple-Output (MIMO) systems is proposed. In the new multi-plexing scheme, each user’s information symbol is dispersed by a User- Specific Matrix (USM) both inspace and time domain and linearly combined at base-station side. And a simple random search al-gorithm, based on capacity maximization criteria, is developed to generate a bank of USMs. Simulations Results are presented to demonstrate the advantages of LDDMA. The Bit Error Rate (BER) reaches 10-3, the performance gains are 3dB and 5dB, compared with Time-Division Linear Dispersion Models (TD-LDC) and BLAST, respectively.