Symbol-level combining for multiple input multiple output (MIMO) systems with hybrid automatic repeat request (HARQ) and/or repetition coding

A system for decoding a signal vector in a multiple-input multiple-output transmission scheme, comprising:

• means for receiving multiple signal vectors corresponding to a common transmit signal vector, wherein each of the received signal vectors is associated with a channel response matrix;
• means for combining the multiple received signal vectors into a combined received signal vector, wherein the combined received signal vector has a noise component;
• means for combining the channel response matrices into a combined channel response matrix;
• means for processing the combined received signal vector based on the combined channel response matrix to produce a modified noise component with a diagonal covariance matrix, wherein the means for processing comprises means for multiplying the combined received signal vector, {tilde over (y)}, by {tilde over (H)}−1/2, where {tilde over (H)} is the combined channel response matrix;
• and
• means for decoding the processed combined received signal vector based on the combined channel response matrix.

A system for decoding a signal vector in a multiple-input multiple-output transmission scheme, comprising:

• a receiver for receiving multiple signal vectors corresponding to a common transmit signal vector, wherein each of the received signal vectors is associated with a channel response matrix;
• a vector combiner for combining the multiple received signal vectors into a combined received signal vector, wherein the combined received signal vector has a noise component;
• a matrix combiner for combining the channel response matrices into a combined channel response matrix;
• a signal processor for processing the combined received signal vector based on the combined channel response matrix to produce a modified noise component with a diagonal covariance matrix, wherein the signal processor processes the combined received signal vector by multiplying the combined received signal vector, {tilde over (y)}, by {tilde over (H)}−1/2, where {tilde over (H)} is the combined channel response matrix;
• and
• a decoder for decoding the processed combined received signal vector based on the combined channel response matrix.