A convolutional decoder includes a first storage, a second storage, a branch metric processor to determine branch metrics for transitions of states from a start step to a last step according to input bit streams, an ACS processor to select maximum likelihood path metrics to determine a survival path according to the branch metrics and to update states of the start step to the first storage and the second storage alternately based on the selection of the maximum likelihood path metrics, and a trace back logic to selectively trace back the survival path based on the states of the start step stored in a selected storage among the first storage and the second storage.

A decoding circuit and a decoding method based on the Viterbi algorithm are provided. The decoding method includes the following steps: decoding an encoded data based on the Viterbi algorithm to generate a decoded data; performing error correction on the decoded data to obtain a data content of the encoded data; comparing the decoded data and the data content to generate bit correction information; using the encoded data to calculate multiple first branch metrics based on the Viterbi algorithm, the first branch metrics corresponding to a target bit of the data content; adjusting at least one of the first branch metrics based on the data content and the bit correction information to generate multiple second branch metrics; and selecting the first branch metrics or the second branch metrics based on the bit correction information.

Techniques are presented for mapping a digital data sequence into a signal point sequence for transmission. The signal point sequence belongs to a set of possible signal point sequences. In one example, a digital data sequence is received. Forbidden branch flags that forbid certain signal points in the possible signal points sequences are applied. The signal point sequence is selected from a subset of all the possible signal point sequences based on the digital data sequence. The subset is defined by the forbidden branch flags.

A decoding circuit and a decoding method based on the Viterbi algorithm are provided. The decoding method includes the following steps: decoding an encoded data based on the Viterbi algorithm to generate a decoded data; performing error correction on the decoded data to obtain a data content of the encoded data; comparing the decoded data and the data content to generate bit correction information; using the encoded data to calculate multiple first branch metrics based on the Viterbi algorithm, the first branch metrics corresponding to a target bit of the data content; adjusting at least one of the first branch metrics based on the data content and the bit correction information to generate multiple second branch metrics; and selecting the first branch metrics or the second branch metrics based on the bit correction information.

A system and method for applying noise to data is described. The system accesses a metric value of a metric of each user from a group of users of an application. The metric indicates a measure of an operation of the application by a corresponding user. The system generates noise values and defines a distribution of the noise values to the group of users. The system modifies the metric value of the metric of each user with a corresponding noise value from the noise values based on the distribution.

Techniques are presented for mapping a digital data sequence into a signal point sequence for transmission. The signal point sequence belongs to a set of possible signal point sequences. In one example, a digital data sequence is received. Forbidden branch flags that forbid certain signal points in the possible signal points sequences are applied. The signal point sequence is selected from a subset of all the possible signal point sequences based on the digital data sequence. The subset is defined by the forbidden branch flags.

A system and method for applying noise to data is described. The system accesses a metric value of a metric of each user from a group of users of an application. The metric indicates a measure of an operation of the application by a corresponding user. The system generates noise values and defines a distribution of the noise values to the group of users. The system modifies the metric value of the metric of each user with a corresponding noise value from the noise values based on the distribution.

The invention discloses a method and a receiving device of the Viterbi algorithm. The method is applicable for a Viterbi decoder that receives an output signal generated by a convolution code encoder processing an original signal. The convolution code encoder includes M registers and M is a positive integer greater than or equal to 2. The method includes the following steps. First, for the first to the Mth data of the output signal, the Viterbi decoder performs the add-compare-select operation based on the known M initial values of the M registers. Then, for the Mth-last to the last data of the output signal, the Viterbi decoder performs the add-compare-select operation based on the known last M bits values of the original signal, thereby reducing the computational complexity of the add-compare-select unit.

The invention discloses a convolutional code decoder and a convolutional code decoding method. The convolutional code decoder performs decoding operation according to a received data and an auxiliary data to obtain a target data and includes an error detection data generation circuit, a channel coding circuit, a selection circuit, and a Viterbi decoding circuit. The error detection data generation circuit performs an error detection operation on the auxiliary data to obtain an error detection data. The channel coding circuit, coupled to the error detection data generation circuit, performs channel coding on the auxiliary data and the error detection data to obtain an intermediate data. The selection circuit, coupled to the channel coding circuit, generates a to-be-decoded data according to the received data and the intermediate data. The Viterbi decoding circuit, coupled to the selection circuit, decodes the to-be-decoded data to obtain the target data.

The invention discloses an improved method and a receiving device of the Viterbi algorithm. The improved method is applicable for a Viterbi decoder that receives an output signal generated by a convolution code encoder processing an original signal. The convolution code encoder includes M registers and M is a positive integer greater than or equal to 2. The improved method includes the following steps. First, for the first to the Mth data of the output signal, the Viterbi decoder performs the add-compare-select operation based on the known M initial values of the M registers. Then, for the Mth-last to the last data of the output signal, the Viterbi decoder performs the add-compare-select operation based on the known last M bits values of the original signal, thereby reducing the computational complexity of the add-compare-select unit.