Method and Apparatus for Detecting Data in Wireless Communication Networks

A method for detecting data in a wireless communication system, the method comprising:

• receiving a digital communication signal, the digital communication signal comprising a plurality of transmitted layers;
• determining an estimated channel matrix based on the digital communication signal;
• determining a first estimated transmitted symbol vector and a mean square error matrix based on a linear analysis of the received digital communication signal;
• determining a first set of bit log likelihood ratios by performing linear minimum mean square error detection based on the first estimated transmitted symbol vector;
• determining a second set of bit log likelihood ratios by performing a tree search for one or more layers in the plurality of transmitted layers in the digital communication signal, based on the first estimated transmitted symbol vector and the mean square error matrix;
• determining a refined set of bit log likelihood ratios based on the first set of bit log likelihood ratios and the second set of bit log likelihood ratios;
• and
• determining a second estimated transmitted symbol vector based on the refined set of bit log likelihood ratios, wherein the tree search comprises:
• selecting a set of parent layers from the plurality of transmitted layers, wherein a number of layers in the set of parent layers is less than or equal to a number of layers in the plurality of transmitted layers;
• determining a shortened channel correlation matrix for each layer in the set of parent layers, based on the mean square error matrix;
• determining an optimal shortened channel matrix, based on each determined shortened channel correlation matrix and the estimated channel matrix;
• and
• selecting a single child node for each parent node in the tree search based on evaluation of a branch metric.

A computer program for detecting data in a wireless communication system, the computer program comprising a non-transitory computer program storage medium comprising instructions that when executed by a processor cause the processor to:

• receive a digital communication signal, the digital communication signal comprising a plurality of transmitted layers;
• determine an estimated channel matrix based on the digital communication signal;
• determine a first estimated transmitted symbol vector and a mean square error matrix based on a linear analysis of the received digital communication signal;
• determine a first set of bit log likelihood ratios by performing linear minimum mean square error detection based on the first estimated transmitted symbol vector;
• determine a second set of bit log likelihood ratios by performing a tree search for one or more layers in the plurality of transmitted layers in the digital communication signal, based on the first estimated transmitted symbol vector and the mean square error matrix;
• determine a refined set of bit log likelihood ratios based on the first set of bit log likelihood ratios and the second set of bit log likelihood ratios;
• and
• determine a second estimated transmitted symbol vector based on the refined set of bit log likelihood ratios, wherein the tree search comprises instructions that when executed by a processor cause the processor to:
• select a set of parent layers from the plurality of transmitted layers, wherein a number of layers in the set of parent layers is less than or equal to a number of layers in the plurality of transmitted layers;
• determine a shortened channel correlation matrix for each layer in the set of parent layers, based on the mean square error matrix;
• determine an optimal shortened channel matrix, based on each determined shortened channel correlation matrix and the estimated channel matrix;
• and
• select a single child node for each parent node in the tree search based on evaluation of a branch metric.