GNU Radio 3.6.5.1 C++ API
digital_ofdm_insert_preamble.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2007,2011 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
6  *
7  * GNU Radio is free software; you can redistribute it and/or modify
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10  * any later version.
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21 
22 #ifndef INCLUDED_DIGITAL_OFDM_INSERT_PREAMBLE_H
23 #define INCLUDED_DIGITAL_OFDM_INSERT_PREAMBLE_H
24 
25 #include <digital_api.h>
26 #include <gr_block.h>
27 #include <vector>
28 
31 
34  const std::vector<std::vector<gr_complex> > &preamble);
35 
36 /*!
37  * \brief insert "pre-modulated" preamble symbols before each payload.
38  * \ingroup ofdm_blk
39  *
40  * <pre>
41  * input 1: stream of vectors of gr_complex [fft_length]
42  * These are the modulated symbols of the payload.
43  *
44  * input 2: stream of char. The LSB indicates whether the corresponding
45  * symbol on input 1 is the first symbol of the payload or not.
46  * It's a 1 if the corresponding symbol is the first symbol,
47  * otherwise 0.
48  *
49  * N.B., this implies that there must be at least 1 symbol in the payload.
50  *
51  *
52  * output 1: stream of vectors of gr_complex [fft_length]
53  * These include the preamble symbols and the payload symbols.
54  *
55  * output 2: stream of char. The LSB indicates whether the corresponding
56  * symbol on input 1 is the first symbol of a packet (i.e., the
57  * first symbol of the preamble.) It's a 1 if the corresponding
58  * symbol is the first symbol, otherwise 0.
59  * </pre>
60  *
61  * \param fft_length length of each symbol in samples.
62  * \param preamble vector of symbols that represent the pre-modulated preamble.
63  */
64 
66 {
68  digital_make_ofdm_insert_preamble(int fft_length,
69  const std::vector<std::vector<gr_complex> > &preamble);
70 
71 protected:
72  digital_ofdm_insert_preamble(int fft_length,
73  const std::vector<std::vector<gr_complex> > &preamble);
74 
75 private:
76  enum state_t {
77  ST_IDLE,
78  ST_PREAMBLE,
79  ST_FIRST_PAYLOAD,
80  ST_PAYLOAD
81  };
82 
83  int d_fft_length;
84  const std::vector<std::vector<gr_complex> > d_preamble;
85  state_t d_state;
86  int d_nsymbols_output;
87  int d_pending_flag;
88 
89  void enter_idle();
90  void enter_first_payload();
91  void enter_payload();
92 
93 
94 public:
96  void enter_preamble();
97 
98  int general_work (int noutput_items,
99  gr_vector_int &ninput_items,
100  gr_vector_const_void_star &input_items,
101  gr_vector_void_star &output_items);
102  void forecast (int noutput_items, gr_vector_int &ninput_items_required);
103 
104 };
105 
106 #endif /* INCLUDED_DIGITAL_OFDM_INSERT_PREAMBLE_H */