Table Of Contents

MT Depuncture Data Stream (G Dataflow)

Version:
    Last Modified: February 7, 2018

    Inserts an erasure value inside the punctured input data stream. The erasure value is equivalent to inserting a null symbol in the position of the input data stream that was previously punctured using MT Puncture Data Stream.

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    Note  

    This node accepts the double data type as input, because the input data stream may correspond to the real BPSK symbols at the demodulator. The erasure value symbol inserted depends on the decoding scheme employed following the depuncturing operation.

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    input data stream

    The data stream with a rate to be increased by the process of depuncturing. This data stream is usually obtained from the output of a block or convolutional encoder.

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    puncture pattern

    A binary-valued matrix that determines which elements in the input data stream are omitted.

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    Note  

    The puncture pattern matrix is chronologically ordered by columns with respect to the input data stream. If the dimensions of the puncture pattern matrix are m×n, the m elements of the first column correspond to the first m elements of the input data stream, and so on.

    Default: 1

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    erasure value

    The symbol value to be inserted into the punctured data stream before decoding. The erasure value is equivalent to inserting a null symbol in the position of the input data stream that was previously punctured using MT Puncture Data Stream.

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    Note  

    The value of the erasure symbol inserted depends on the decoding scheme employed following the depuncturing operation. Using a soft-decision Viterbi decoder with n soft bits used to quantize every BPSK modulated symbol, the erasure value must be (2 n soft -1)/2. On the other hand, if the decoder is an unquantized Viterbi decoder, which accepts real-valued BPSK data symbols lying in [-1, 1], the erasure value must be 0. The integer value 0 denotes a strong logic 0, and 2 n soft -1 denotes a strong logic 1.

    Default: 0

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    error in

    Error conditions that occur before this node runs.

    The node responds to this input according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

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    reset?

    A Boolean that determines whether this node uses the stored state information from a previous iteration while depuncturing the input data stream in the current iteration.

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    Note  

    When the length L of the input data stream is not an integer multiple of the product P×Q of the P×Q puncture pattern matrix, the last L modulo (P×Q) bits are buffered inside the node.

    TRUE Clears all previous state information and reinitializes the buffers.
    FALSE Uses the stored state information from the previous iteration while depuncturing the input data stream in the current iteration. The buffered elements are added to the beginning of the input data stream during the next iteration, prior to the depuncturing operation.

    Default: TRUE

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    output data stream

    The data stream returned by this node, which consists of all elements in the input data stream in addition to those that were inserted during the depuncturing operation.

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    error out

    Error information.

    The node produces this output according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

    Web Server: Not supported in VIs that run in a web application


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