OFDM Receiver: Difference between revisions

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; Occupied Carriers
; Occupied Carriers
: A vector of vectors describing which OFDM carriers are occupied.
: A vector of vectors describing which OFDM carriers are occupied with data symbols.


; Pilot Carriers
; Pilot Carriers
Line 23: Line 23:


; Pilot Symbols
; Pilot Symbols
: The pilot symbols.
: A vector of vectors indicating the pilot symbols.


; Sync Word 1
; Sync Word 1

Revision as of 13:11, 1 June 2022

Hierarchical block for OFDM demodulation.

The input is a complex baseband signal (e.g. from a UHD source). The detected packets are output as a stream of packed bits on the output.

Parameters

FFT Length
The length of FFT (integer).
Cyclic Prefix Length
The length of cyclic prefix in total samples (integer).
Packet Length Tag Key
The name of the tag giving packet length at the input.
Occupied Carriers
A vector of vectors describing which OFDM carriers are occupied with data symbols.
Pilot Carriers
A vector of vectors describing which OFDM carriers are occupied with pilot symbols.
Pilot Symbols
A vector of vectors indicating the pilot symbols.
Sync Word 1
The first sync preamble symbol. This has to be with zeros on alternating carriers. Used for fine and coarse frequency offset and timing estimation.
Sync Word 2
The second sync preamble symbol. This has to be filled entirely. Also used for coarse frequency offset and channel estimation.
Header Modulation
Payload Modulation
Scramble Bits
Activates the scramblers (set this to True unless debugging)
Log Debug Info
Write output into log files (Warning: creates lots of data!)

Example Flowgraph

This flowgraph can be found at https://github.com/gnuradio/gnuradio/blob/master/gr-digital/examples/ofdm/ofdm_loopback.grc

Ofdm loopback example fg.png

Source Files

Python file
[1]
Block definition
[2]