Iterative minimum mean square error (mmse) detection methods for multiple-input multiple-output (mimo) communication systems

A method of detecting signals in a multiple-input multiple-output (MIMO) communication system, the method comprising:

• receiving a signal vector and a channel matrix associated with transmissions from a plurality of antennas, each element of the signal vector corresponding to a receive antenna;
• initializing symbol information for the signal vector;
• applying a minimum mean square error (MMSE) detection process to the signal vector;
• generating one or more candidate symbol vectors for one or more transmit layers using a maximum likelihood approximation (MLA), wherein each candidate symbol vector is expanded using the MMSE detection process applied to remaining transmit layers;
• selecting hard-decision symbol estimates from among the evaluated candidate symbol vectors;
• and
• outputting final hard-decision symbol estimates from the MMSE detection process as detected symbols.

A method of detecting signals in a multiple-input multiple-output (MIMO) communication system, the method comprising:

• receiving a signal vector and a channel matrix associated with transmissions from a plurality of antennas, each element of the signal vector corresponding to a receive antenna;
• initializing symbol information for the signal vector;
• applying a minimum mean square error (MMSE) detection process to the signal vector;
• generating one or more candidate symbol vectors for one or more transmit layers using a maximum likelihood approximation (MLA), wherein each candidate symbol vector is expanded using the MMSE detection process applied to remaining transmit layers;
• computing soft-decision probabilities for symbols of the signal vector based on the evaluated candidate symbol vectors;
• and
• outputting final symbol estimates from the soft-decision probabilities as detected symbols.