digital_ofdm_carrier_allocator_cvc Class Reference
Create frequency domain OFDM symbols from complex values, add pilots.This block turns a stream of complex, scalar modulation symbols into vectors which are the input for an IFFT in an OFDM transmitter. It also supports the possibility of placing pilot symbols onto the carriers. More...
#include <digital_ofdm_carrier_allocator_cvc.h>
Public Member Functions | |
| ~digital_ofdm_carrier_allocator_cvc () | |
| std::string | len_tag_key () |
| const int | fft_len () |
| std::vector< std::vector< int > > | occupied_carriers () |
| int | work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) |
| Just like gr_block::general_work, but makes sure the input is valid. | |
Protected Member Functions | |
| int | calculate_output_stream_length (const gr_vector_int &ninput_items) |
| Calculate the number of output items. | |
Friends | |
| DIGITAL_API digital_ofdm_carrier_allocator_cvc_sptr | digital_make_ofdm_carrier_allocator_cvc (int fft_len, const std::vector< std::vector< int > > &occupied_carriers, const std::vector< std::vector< int > > &pilot_carriers, const std::vector< std::vector< gr_complex > > &pilot_symbols, const std::string &len_tag_key) |
Detailed Description
Create frequency domain OFDM symbols from complex values, add pilots.
This block turns a stream of complex, scalar modulation symbols into vectors which are the input for an IFFT in an OFDM transmitter. It also supports the possibility of placing pilot symbols onto the carriers.
The carriers can be allocated freely, if a carrier is not allocated, it is set to zero. This allows doing OFDMA-style carrier allocations.
Input: A tagged stream of complex scalars. The first item must have a tag containing the number of complex symbols in this frame. Output: A tagged stream of complex vectors of length fft_len. This can directly be connected to an FFT block. Make sure to set this block to 'reverse' for the IFFT and to deactivate FFT shifting.
Carrier indexes are always such that index 0 is the DC carrier (note: you should not allocate this carrier). The carriers below the DC carrier are either indexed with negative numbers, or with indexes larger than fft_len/2. Index -1 and index fft_len-1 both identify the carrier below the DC carrier.
Constructor & Destructor Documentation
| digital_ofdm_carrier_allocator_cvc::~digital_ofdm_carrier_allocator_cvc | ( | ) |
Member Function Documentation
| int digital_ofdm_carrier_allocator_cvc::calculate_output_stream_length | ( | const gr_vector_int & | ninput_items | ) | [protected, virtual] |
Calculate the number of output items.
This is basically the inverse function to forecast(): Given a number of input items, it returns the maximum number of output items.
You most likely need to override this function, unless your block is a sync block or integer interpolator/decimator.
Reimplemented from gr_tagged_stream_block.
| const int digital_ofdm_carrier_allocator_cvc::fft_len | ( | ) | [inline] |
| std::string digital_ofdm_carrier_allocator_cvc::len_tag_key | ( | ) | [inline] |
References gr_tagged_stream_block::d_length_tag_key_str.
| std::vector<std::vector<int> > digital_ofdm_carrier_allocator_cvc::occupied_carriers | ( | ) | [inline] |
| int digital_ofdm_carrier_allocator_cvc::work | ( | int | noutput_items, |
| gr_vector_int & | ninput_items, | ||
| gr_vector_const_void_star & | input_items, | ||
| gr_vector_void_star & | output_items | ||
| ) | [virtual] |
Just like gr_block::general_work, but makes sure the input is valid.
The user must override work to define the signal processing code. Check the documentation for general_work() to see what happens here.
Like gr_sync_block, this calls consume() for you (it consumes ninput_items[i] items from the i-th port).
A note on tag propagation: The PDU length tags are handled by other functions, but all other tags are handled just as in any other gr_block. So, most likely, you either set the tag propagation policy to TPP_DONT and handle the tag propagation manually, or you propagate tags through the scheduler and don't do anything here.
- Parameters:
-
noutput_items The size of the writable output buffer ninput_items The exact size of the items on every input for this particular PDU. These will be consumed if a length tag key is provided! input_items See gr_block output_items See gr_block
Implements gr_tagged_stream_block.
Friends And Related Function Documentation
| DIGITAL_API digital_ofdm_carrier_allocator_cvc_sptr digital_make_ofdm_carrier_allocator_cvc | ( | int | fft_len, |
| const std::vector< std::vector< int > > & | occupied_carriers, | ||
| const std::vector< std::vector< int > > & | pilot_carriers, | ||
| const std::vector< std::vector< gr_complex > > & | pilot_symbols, | ||
| const std::string & | len_tag_key | ||
| ) | [friend] |
The documentation for this class was generated from the following file:
