Table Of Contents

MT Depuncture Data Stream (G Dataflow)

Last Modified: January 9, 2017

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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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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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.

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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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.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported


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