diff options
Diffstat (limited to 'gr-digital/include/digital_ofdm_cyclic_prefixer.h')
| -rw-r--r-- | gr-digital/include/digital_ofdm_cyclic_prefixer.h | 62 |
1 files changed, 49 insertions, 13 deletions
diff --git a/gr-digital/include/digital_ofdm_cyclic_prefixer.h b/gr-digital/include/digital_ofdm_cyclic_prefixer.h index 1b9682bb35..e6c36b4c14 100644 --- a/gr-digital/include/digital_ofdm_cyclic_prefixer.h +++ b/gr-digital/include/digital_ofdm_cyclic_prefixer.h @@ -24,36 +24,72 @@ #define INCLUDED_DIGITAL_OFDM_CYCLIC_PREFIXER_H #include <digital_api.h> -#include <gr_sync_interpolator.h> -#include <stdio.h> +#include <gr_tagged_stream_block.h> class digital_ofdm_cyclic_prefixer; typedef boost::shared_ptr<digital_ofdm_cyclic_prefixer> digital_ofdm_cyclic_prefixer_sptr; -DIGITAL_API digital_ofdm_cyclic_prefixer_sptr -digital_make_ofdm_cyclic_prefixer (size_t input_size, size_t output_size); +/*! + * \param input_size FFT length (i.e. length of the OFDM symbols) + * \param output_size FFT length + cyclic prefix length (in samples) + * \param rolloff_len Length of the rolloff flank in samples + * \param len_tag_key For framed processing the key of the length tag + */ +DIGITAL_API digital_ofdm_cyclic_prefixer_sptr +digital_make_ofdm_cyclic_prefixer (size_t input_size, + size_t output_size, + int rolloff_len=0, + const std::string &len_tag_key=""); /*! - * \brief adds a cyclic prefix vector to an input size long ofdm - * symbol(vector) and converts vector to a stream output_size long. + * \brief Adds a cyclic prefix and performs pulse shaping on OFDM symbols. * \ingroup ofdm_blk + * + * Input: OFDM symbols (in the time domain, i.e. after the IFFT). Optionally, + * entire frames can be processed. In this case, \p len_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 \p rolloff_len 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. */ -class DIGITAL_API digital_ofdm_cyclic_prefixer : public gr_sync_interpolator +class DIGITAL_API digital_ofdm_cyclic_prefixer : public gr_tagged_stream_block { friend DIGITAL_API digital_ofdm_cyclic_prefixer_sptr - digital_make_ofdm_cyclic_prefixer (size_t input_size, size_t output_size); + digital_make_ofdm_cyclic_prefixer (size_t input_size, size_t output_size, int rolloff_len, const std::string &len_tag_key); + protected: - digital_ofdm_cyclic_prefixer (size_t input_size, size_t output_size); + digital_ofdm_cyclic_prefixer (size_t input_size, size_t output_size, int rolloff_len, const std::string &len_tag_key); + + //! Return the number of complex samples from the number of OFDM symbols (includes rolloff) + int calculate_output_stream_length(const gr_vector_int &ninput_items); public: - int work (int noutput_items, - gr_vector_const_void_star &input_items, - gr_vector_void_star &output_items); + int work(int noutput_items, + gr_vector_int &ninput_items, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items); + private: - size_t d_input_size; + size_t d_fft_len; + //! FFT length + CP length in samples size_t d_output_size; + //! Length of the cyclic prefix in samples + int d_cp_size; + //! Length of pulse rolloff in samples + int d_rolloff_len; + //! Buffers the up-flank (at the beginning of the cyclic prefix) + std::vector<float> d_up_flank; + //! Buffers the down-flank (which trails the symbol) + std::vector<float> d_down_flank; + std::vector<gr_complex> d_delay_line; // We do this explicitly to avoid outputting zeroes (i.e. no history!) }; #endif /* INCLUDED_DIGITAL_OFDM_CYCLIC_PREFIXER_H */ + |