OFDM Cyclic Prefixer: Difference between revisions

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[[Category:Block Docs]]
[[Category:Block Docs]]
[[Category:Stub Docs]]
Adds a cyclic prefix and performs pulse shaping on OFDM symbols.
This is the template for the [[:Category:Block_Docs|"Page-per-block Docs"]].  This first section should describe what the block does and how to use it, using however many paragraphs necessary.  Note that the title of the wiki page should match the block's name in GRC, i.e. the one defined in the block's .grc file.  Look at the [[FFT]] Block for a good example.


As this is a basic template, it's also in the [[:Category:Stub_Docs|"Stub Docs category"]]. Please improve it.
; Input: OFDM symbols (in the time domain, i.e. after the IFFT). Optionally, entire frames can be processed. In this case, Length Tag Key must be specified which holds the key of the tag that denotes how many OFDM symbols are in a frame.
 
; Output: A stream of (scalar) complex symbols, which include the cyclic prefix and the pulse shaping.
: Note: If complete frames are processed, and Rolloff is greater than zero, the final OFDM symbol is followed by the delay line of the pulse shaping.
 
The pulse shape is a raised cosine in the time domain.


== Parameters ==
== Parameters ==
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>


; Param 1 (''R'')
; FFT Length
: Description of parameter, provide any tips or recommended values.  Note that the name of the parameter above should match the param's label that shows up in grc (e.g. Sample Rate).
: FFT Length (i.e. length of the OFDM symbols)
 
; CP Length
: Cyclic prefix length (in samples)
 
; Rolloff
: Length of the rolloff flank in samples


; Param 2
; Length Tag Key
: blah blah blah
: For framed processing, the key of the length tag


== Example Flowgraph ==
== Example Flowgraph ==
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; C++ files
; C++ files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-digital/lib/ofdm_cyclic_prefixer_impl.cc]


; Header files
; Header files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-digital/lib/ofdm_cyclic_prefixer_impl.h]


; Public header files
; Public header files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-digital/include/gnuradio/digital/ofdm_cyclic_prefixer.h]


; Block definition
; Block definition
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-digital/grc/digital_ofdm_cyclic_prefixer.block.yml]

Revision as of 15:13, 9 September 2019

Adds a cyclic prefix and performs pulse shaping on OFDM symbols.

Input
OFDM symbols (in the time domain, i.e. after the IFFT). Optionally, entire frames can be processed. In this case, Length Tag Key must be specified which holds the key of the tag that denotes how many OFDM symbols are in a frame.
Output
A stream of (scalar) complex symbols, which include the cyclic prefix and the pulse shaping.
Note: If complete frames are processed, and Rolloff is greater than zero, the final OFDM symbol is followed by the delay line of the pulse shaping.

The pulse shape is a raised cosine in the time domain.

Parameters

FFT Length
FFT Length (i.e. length of the OFDM symbols)
CP Length
Cyclic prefix length (in samples)
Rolloff
Length of the rolloff flank in samples
Length Tag Key
For framed processing, the key of the length tag

Example Flowgraph

Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.

Source Files

C++ files
[1]
Header files
[2]
Public header files
[3]
Block definition
[4]