Method of reduced state decoding and decoder thereof
AssigneeHuawei Technologies Co., Ltd.
InventorsYiqun Ge, Wuxian Shi
Life of this patent
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Abstract
Methods and devices are disclosed for receiving and decoding sparsely encoded data sequences using a message passing algorithm (MPA) or maximum likelihood sequence estimation (MLSE). Such data sequences may be used in wireless communications systems supporting multiple access, such as sparse code multiple access (SCMA) systems. The Methods and devices reduce the number of states in a search space for each received signal and associated function node based on a search threshold based on a characteristic related to the received signal and/or to a quality of a resource element over which the received signal is transmitted.
Claims13
A method of decoding a plurality of signals, comprising, at a receiving device:
- receiving a plurality of received signals over a corresponding plurality of resource elements, wherein each received signal is associated with a plurality of possible states and represents sparsely encoded data combined from a plurality of input signals that have been sparsely encoded using respective codewords;
- generating a received signal estimate for each of the plurality of signals;
- determining, for each of the plurality of received signals:
- a search threshold based on at least one of:
- (i) a characteristic of the received signal and (ii) a quality of the corresponding resource element over which the received signal was received, wherein the characteristic of the received signal comprises at least one of signal to noise ratio (SNR) and signal power level, and the quality of the corresponding resource element for determining the search threshold comprises at least one of a channel factor estimate and a channel factor estimate to channel noise ratio;
- and
- a respective reduced search space comprising a number of states within the search threshold from the received signal estimate for the received signal;
- and
- decoding each of the plurality of the received signal estimates within the respective reduced search spaces to recover the input signals.
A system for decoding a plurality of signals, comprising a non-transitory memory configured to store instructions and a processor configured to receive instructions from the non-transitory memory to cause the system to:
- receive, at a signal interface, a plurality of received signals over a corresponding plurality of resource elements, wherein each received signal is associated with a plurality of possible states and represents sparsely encoded data combined from a plurality of input signals that have each been sparsely encoded using respective codewords;
- generate, at a pre-processing module, a received signal estimate for each of the plurality of received signals;
- determine, at a Conditional Channel Probability(CCC) Calculator, a respective reduced search space for each of the plurality of received signal estimates, the reduced search space for each received signal estimate comprising a number of states within a search threshold from the received signal estimate, the search threshold for each received signal estimate being based on at least one of:
- (i) a characteristic related to the received signal that the received signal estimate was generated for and (ii) a quality of the resource element corresponding to the received signal that the received signal estimate was generated for, wherein the characteristic related of the received signal comprises at least one of signal to noise ratio (SNR) and signal power level, and the quality of the corresponding resource element for determining the search threshold comprises at least one of a channel factor estimate and a channel factor estimate to channel noise ratio;
- and
- decode each of the received signal estimates within the respective reduced search spaces to recover the input signals.
Dependencies are inferred from the claim text.