Reduced-complexity multiple-input, multiple-output detection
AssigneeAgere Systems Inc.
InventorsNils Graef, Joachim S. Hammerschmidt
Life of this patent
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Abstract
A wireless receiver detects signals generated with a multiple-input, multiple-output (MIMO) transmitter. The receiver applies maximum-likelihood detection (MLD) for soft-output signal detection, where an MLD exhaustive search across all candidate vectors is performed recursively by computing and accumulating the differences between, for example, the Euclidean metrics of consecutive candidate tests. Difference terms used for the accumulation are also calculated recursively. An ordering of candidates, such as by a triangular-waveform shaped ordering, is employed such that only one candidate variable is changed between any two consecutive candidate evaluations, leading to a reduced set of computations.
Claims27
An apparatus for detecting a data pattern from a plurality of received signals, the apparatus comprising:
- a mapper providing a sequence of scan values derived from a sequence of count values, each scan value selecting one of a set of candidates in a varying pattern, wherein the mapper generates the sequence of scan values so as to select each of the set of candidates in a periodic scan pattern;
- a difference term generator providing, for each of the sequence of count values, a difference term between a current metric value and a previous metric value based on a set of coefficients for a received symbol;
- an accumulator combining, for each of a sequence of count values, the difference term with one or more previous difference terms to provide one of a set of metric values;
- and
- a comparator generating, based on the set of metric values corresponding to the sequence of scan values, soft-output values corresponding to the data pattern;
- wherein the received symbol is represented by symbol values in two or more dimensions, and the mapper generates the sequence of scan values so as to select each of the set of candidates in a scan pattern in each dimension, the scan pattern of each dimension varying in frequency with the scan pattern of at least one other dimension.
For a signal processing application, a computer-implemented method of detecting a data pattern from a plurality of received signals, the method comprising the steps of:
- (a) the computer providing a sequence of scan values derived from a sequence of count values, each scan value selecting one of a set of candidates in a varying pattern, wherein step (a) includes the step of generating the sequence of scan values so as to select each of the set of candidates in a periodic scan pattern;
- (b) the computer generating, for each of the sequence of count values, a difference term between a current metric value and a previous metric value based on a set of coefficients for a received symbol;
- (c) the computer combining, for each of a sequence of count values, the difference term with one or more previous difference terms to provide one of a set of metric values;
- and
- (d) the computer generating, based on the set of metric values corresponding to the sequence of scan values, soft-output values corresponding to the data pattern;
- wherein, for step (a), the received symbol is represented by symbol values in two or more dimensions, and step (a) includes the step of the computer generating the sequence of scan values so as to select each of the set of candidates in a scan pattern in each dimension, the scan pattern of each dimension varying in frequency with the scan pattern of at least one other dimension.
A computer-readable medium having stored thereon a plurality of instructions, the plurality of instructions including instructions which, when executed by a processor, cause the processor to implement a method for detecting a data pattern from a plurality of received signals, the method comprising the steps of:
- (a) providing a sequence of scan values derived from a sequence of count values, each scan value selecting one of a set of candidates in a varying pattern, wherein step (a) includes the step of generating the sequence of scan values so as to select each of the set of candidates in a periodic scan pattern;
- (b) generating, for each of the sequence of count values, a difference term between a current metric value and a previous metric value based on a set of coefficients for a received symbol;
- (c) combining, for each of a sequence of count values, the difference term with one or more previous difference terms to provide one of a set of metric values;
- and
- (d) generating, based on the set of metric values corresponding to the sequence of scan values, soft-output values corresponding to the data pattern;
- wherein, for step (a), the received symbol is represented by symbol values in two or more dimensions, and step (a) includes the step of generating the sequence of scan values so as to select each of the set of candidates in a scan pattern in each dimension, the scan pattern of each dimension varying in frequency with the scan pattern of at least one other dimension.
Dependencies are inferred from the claim text.