Soft bit computation unit for MIMO detection and error correction

A Multiple Input Multiple Output (MIMO) detector, comprising:

• a plurality of receive antennas for receiving a signal;
• a hard-output unit which performs a first decoding operation on the signal using channel estimate information and a decoding tree to produce output data for a bit estimation value comprising a maximum likelihood solution along with a naturally ordered vector identifying all explored node metrics and node indices;
• and
• a soft-output unit comprising a mask computation unit for generating a set of bit-masks and a log-likelihood ratio (LLR) computation unit for generating soft bit values for each bit estimation value by:
• determining the set of bit-masks through repetition and indexing operations applied on the explored node indices;
• masking the naturally ordered vector with the set of bit-masks to generate masked node metrics;
• determining candidate soft bit values by subtracting metrics of all nodes that form the maximum likelihood solution from the masked node metrics;
• and
• determining a final soft bit value by identifying which of the candidate soft bit values has a lowest value.