Low complexity iterative MIMO receiver based on successive soft interference cancellation and MMSE spatial filtering

A computer readable device having computer readable program code for recovering a bit data sequence from a received signal that comprises a plurality of symbols transmitted by a space-time bit-interleaved coded modulation (ST-BICM) transmitter comprising:

• receiving, by a processor, a vector comprising symbol streams from a plurality of transmit antennae;
• and
• removing, by the processor, a contribution of the symbol streams from the received vector to produce a less corrupted version of the received vector by individually demapping each of the symbol streams comprising the received vector successively, in accordance with an optimal order, the demapping comprising:
• calculating, by the processor, a log-likelihood ratio (LLR) value for each stream of the symbol streams;
• optimizing, by the processor, ordering of the symbol streams to enable interference cancellation during demapping of a first stream of the symbol streams, wherein optimizing ordering comprises applying a spatial filter to the symbol streams and selecting a best stream from the symbol streams as the first stream to be demapped;
• demapping, by the processor, each individual symbol stream of the symbol streams successively from the received vector in accordance with the optimized order by successively reconstructing, by the processor, each symbol stream and removing the contribution of each symbol stream individually from the received vector, wherein the reconstructing comprises utilizing the more current of an LLR value fed back from a decoder or an LLR value from a previous demapping;
• and
• filtering, by the processor, each reconstructed symbol stream with its respective channel response and removing the filtered symbol stream from the received vector.

A system comprising:

• a memory device;
• and
• a processor communicably coupled to the memory device, the processor to:
• receive a vector comprising symbol streams from a plurality of transmit antennae;
• and
• remove a contribution of the symbol streams from the received vector to produce a less corrupted version of the received vector by individually demapping each of the symbol streams comprising the received vector successively, in accordance with an optimal order, the demapping comprising:
• calculating, by the processor, a log-likelihood ratio (LLR) value for each stream of the symbol streams;
• optimizing, by the processor, ordering of the symbol streams to enable interference cancellation during demapping of a first stream of the symbol streams, wherein optimizing ordering comprises applying a spatial filter to the symbol streams and selecting a best stream from the symbol streams as the first stream to be demapped;
• demapping, by the processor, each individual symbol stream of the symbol streams successively from the received vector in accordance with the optimized order by successively reconstructing, by the processor, each symbol stream and removing the contribution of each symbol stream individually from the received vector, wherein the reconstructing comprises utilizing the more current of an LLR value fed back from a decoder or an LLR value from a previous demapping;
• and
• filtering, by the processor, each reconstructed symbol stream with its respective channel response and removing the filtered symbol stream from the received vector.