Apparatus and method for trellis-based detection in a communication system

A computer program product comprising a program code stored in a non-transitory computer readable medium configured to:

• construct a trellis representing a transmitted signal formed from a plurality of symbols transmitted by a number of transmit antennas, each symbol having a constellation size, said trellis being formed of columns representing said number of transmit antennas and rows representing values of said plurality of symbols with nodes at intersections thereof;
• form a log likelihood ratio at said nodes of said trellis as a log-sum of a number of exponential terms including a priori information corresponding to a hypothesized transmitted bit value of 0 or 1 of said plurality of symbols, said number of exponential terms being limited by a function of a number of most likely paths of said trellis extending from each node of said trellis and said constellation size;
• and
• form a list at each node of said trellis of a size limited to said number of said most likely paths of said trellis extending from each node of said trellis.

A method, comprising:

• constructing a trellis representing a transmitted signal formed from a plurality of symbols transmitted by a number of transmit antennas, each symbol having a constellation size, said trellis being formed of columns representing said number of transmit antennas and rows representing values of said plurality of symbols with nodes at intersections thereof;
• forming a log likelihood ratio at said nodes of said trellis as a log-sum of a number of exponential terms including a priori information corresponding to a hypothesized transmitted bit value of 0 or 1 of said plurality of symbols, said number of exponential terms being limited by a function of a number of most likely paths of said trellis extending from each node of said trellis and said constellation size;
• and
• forming a list at each node of said trellis of a size limited to said number of said most likely paths of said trellis extending from each node of said trellis.