Efficient dual sphere soft demapping for multi antenna communication systems

A wireless device comprising:

• one or more processors configured to:
• perform a first QR decomposition on a first matrix relating to a first stream and a second stream among a plurality of spatial streams;
• perform a second QR decomposition on a second matrix relating to the first stream and the second stream, different from the first matrix;
• and
• perform, using a result of the first QR decomposition and a result of the second QR decomposition, soft demapping using sphere decoding on the first stream and the second stream.

A method for demapping in a wireless device, the method comprising:

• performing, by one or more processors, first soft demapping using sphere decoding on first data relating to a first stream and a second stream among a plurality of spatial streams;
• performing, by the one or more processors, second soft demapping using sphere decoding on second data relating to the first stream and the second stream, different from the first data;
• and
• determining, by the one or more processors, using a result of the first soft demapping and a result of the second soft demapping, log likelihood ratio (LLR) values of the first stream and the second stream.