System and method for MIMO decoding

A method for decoding received data, the received data comprising in-phase data and quadrature data and the received data including a combination of data transmitted by multiple transmit antennas, the method comprising:

• (a) defining a bounded region based on a number of most significant bits for the in-phase and the quadrature received data, the number of most significant bits being less than or equal to a total number of bits for each of the in-phase and the quadrature received data;
• (b) calculating a current possible candidate to the same number of most significant bits of the received data used to define the bounded region;
• (c) when the current possible candidate is considered to be inside the bounded region, repeating (a) and (b) until the current possible candidate is considered to be outside the bounded region, wherein in (a) the number of most significant bits for the in-phase and the quadrature received data is increased and another bounded region smaller than the first bounded region is defined using the increased number of significant bits and in (b) the current possible candidate is calculated to the same number of most significant bits as the increased number of most significant bits for the in-phase and the quadrature received data;
• (d) when the current possible candidate is considered to be outside the bounded region, storing an identifier and the most significant bits of the current possible candidate;
• (e) if no previous possible candidate has been stored, storing the current possible candidate, or if at least one previous possible candidate has been stored, comparing the number most significant bits of the current possible candidate with the number of most significant bits of the stored previous possible candidate, and discarding the candidate with the lesser number of most significant bits, or additionally storing the current candidate if the number of most significant bits is the same;
• (f) repeating (a) to (e) with all possible candidates until only one possible candidate remains or if more than one candidate remains, calculating all the bits for each remaining candidate and selecting the candidate having a closest Euclidean distance to the received data to obtain one remaining candidate;
• and
• (g) outputting signals representing an identifier of the one remaining candidate.

A wireless device comprising :

• a processor for controlling operation of the wireless device;
• and
• a communications subsystem coupled to the processor for communicating with a communications network and for receiving data comprising in-phase data and quadrature data, the received data including a combination of data transmitted by multiple transmit antennas;
• the processor being configured to implement a MIMO decoding module comprising instructions to cause the device to:
• (a) define a bounded region based on a number of most significant bits for the in-phase and the quadrature received data, the number of most significant bits being less than or equal to a total number of bits for each of the in-phase and the quadrature received data;
• (b) calculate possible candidates to the same number of most significant bits of the received data used to define the bounded region;
• (c) store the calculated most significant bits of any possible candidates considered to be inside the bounded region and discard any candidates considered to be outside the bounded region;
• (d) increase the number of most significant bits for the in-phase and the quadrature received data;
• (e) repeat (a) to (d) until no more than one candidate remains, wherein (a) is repeated using the increased number of most significant bits and (b) is repeated using only the stored most significant bits of possible candidates;
• (f) when less than one candidate remains, calculate all the bits for each remaining candidate of an immediately previous iteration and select the candidate having a closest Euclidean distance to the received data to obtain one remaining candidate;
• and
• (g) output signals representing an identifier of the one remaining candidate.

A wireless device comprising :

• a processor for controlling operation of the wireless device;
• and
• a communications subsystem coupled to the processor for communicating with a communications network and for receiving data comprising in-phase data and quadrature data, the received data including a combination of data transmitted by multiple transmit antennas;
• the processor being configured to implement a MIMO decoding module comprising instructions to cause the device to:
• (a) define a bounded region based on a number of most significant bits for the in-phase and the quadrature received data, the number of most significant bits being less than or equal to a total number of bits for each of the in-phase and the quadrature received data;
• (b) calculate a current possible candidate to the same number of most significant bits of the received data used to define the bounded region;
• (c) when the current possible candidate is considered to be inside the bounded region, repeat (a) and (b) until the current possible candidate is considered to be outside the bounded region, wherein in (a) the number of most significant bits for the in-phase and the quadrature received data is increased and another bounded region smaller than the first bounded region is defined using the increased number of significant bits and in (b) the current possible candidate is calculated to the same number of most significant bits as the increased number of most significant bits for the in-phase and the quadrature received data;
• (d) when the current possible candidate is considered to be outside the bounded region, store an identifier and the most significant bits of the current possible candidate;
• (e) if no previous possible candidate has been stored, store the current possible candidate, or if at least one previous possible candidate has been stored, compare the number most significant bits of the current possible candidate with the number of most significant bits of the stored previous possible candidate, and discard the candidate with the lesser number of most significant bits, or additionally store the current candidate if the number of most significant bits is the same;
• (f) repeat (a) to (e) with all possible candidates until only one possible candidate remains or if more than one candidate remains, calculate all the bits for each remaining candidate and select the candidate having a closest Euclidean distance to the received data to obtain one remaining candidate;
• and
• (g) output signals representing an identifier of the one remaining candidate.

A non-transitory computer program product comprising a computer readable medium tangibly embodying code executable by a processor to, after receiving data comprising in-phase data and quadrature data, the received data including a combination of data transmitted by multiple transmit antennas:

• (a) define a bounded region based on a number of most significant bits for the in-phase and the quadrature received data, the number of most significant bits being less than or equal to a total number of bits for each of the in-phase and the quadrature received data;
• (b) calculate possible candidates to the same number of most significant bits of the received data used to define the bounded region;
• (c) store the calculated most significant bits of any possible candidates considered to be inside the bounded region and discard any candidates considered to be outside the bounded region;
• (d) increase the number of most significant bits for the in-phase and the quadrature received data;
• (e) repeat (a) to (d) until no more than one candidate remains, wherein (a) is repeated using the increased number of most significant bits and (b) is repeated using only the stored most significant bits of possible candidates;
• (f) when less than one candidate remains, calculate all the bits for each remaining candidate of an immediately previous iteration and select the candidate having a closest Euclidean distance to the received data to obtain one remaining candidate;
• and
• (g) output signals representing an identifier of the one remaining candidate.

A non-transitory computer program product comprising a computer readable medium tangibly embodying code executable by a processor to, after receiving data comprising in-phase data and quadrature data, the received data including a combination of data transmitted by multiple transmit antennas:

• (a) define a bounded region based on a number of most significant bits for the in-phase and the quadrature received data, the number of most significant bits being less than or equal to a total number of bits for each of the in-phase and the quadrature received data;
• (b) calculate a current possible candidate to the same number of most significant bits of the received data used to define the bounded region;
• (c) when the current possible candidate is considered to be inside the bounded region, repeat (a) and (b) until the current possible candidate is considered to be outside the bounded region, wherein in (a) the number of most significant bits for the in-phase and the quadrature received data is increased and another bounded region smaller than the first bounded region is defined using the increased number of significant bits and in (b) the current possible candidate is calculated to the same number of most significant bits as the increased number of most significant bits for the in-phase and the quadrature received data;
• (d) when the current possible candidate is considered to be outside the bounded region, store an identifier and the most significant bits of the current possible candidate;
• (e) if no previous possible candidate has been stored, store the current possible candidate, or if at least one previous possible candidate has been stored, compare the number most significant bits of the current possible candidate with the number of most significant bits of the stored previous possible candidate, and discard the candidate with the lesser number of most significant bits, or additionally store the current candidate if the number of most significant bits is the same;
• (f) repeat (a) to (e) with all possible candidates until only one possible candidate remains or if more than one candidate remains, calculate all the bits for each remaining candidate and select the candidate having a closest Euclidean distance to the received data to obtain one remaining candidate;
• and
• (g) output signals representing an identifier of the one remaining candidate.