GNU Radio Manual and C++ API Reference 3.9.4.0
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header_format_ofdm.h
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1/* -*- c++ -*- */
2/* Copyright 2016 Free Software Foundation, Inc.
3 *
4 * This file is part of GNU Radio
5 *
6 * SPDX-License-Identifier: GPL-3.0-or-later
7 *
8 */
9
10#ifndef INCLUDED_DIGITAL_HEADER_FORMAT_OFDM_H
11#define INCLUDED_DIGITAL_HEADER_FORMAT_OFDM_H
12
15#include <pmt/pmt.h>
16#include <boost/crc.hpp>
17
18namespace gr {
19namespace digital {
20
21/*!
22 * \brief Header formatter that includes the payload length,
23 * packet number, and a CRC check on the header.
24 * \ingroup packet_operators_blk
25 *
26 * \details
27 *
28 * Child class of header_format_base. This version's header
29 * format looks like:
30 *
31 * \li length (12 bits): length of the payload
32 * \li number (12 bits): packet number
33 * \li CRC8 (8 bits): A CRC8 check on the header contents
34 *
35 * Instead of duplicating the payload length, we only add it once
36 * and use the CRC8 to make sure it's correctly received.
37 *
38 * \verbatim
39 | 0 -- 11 | 12 -- 23 | 24 -- 31 |
40 | len | pkt len | CRC8 |
41 \endverbatim
42 *
43 * Reimplements packet_header_default in the style of the
44 * header_format_base.
45 */
47{
48public:
49 typedef std::shared_ptr<header_format_ofdm> sptr;
50 header_format_ofdm(const std::vector<std::vector<int>>& occupied_carriers,
51 int n_syms,
52 const std::string& len_key_name = "packet_len",
53 const std::string& frame_key_name = "frame_len",
54 const std::string& num_key_name = "packet_num",
55 int bits_per_header_sym = 1,
56 int bits_per_payload_sym = 1,
57 bool scramble_header = false);
59
60 /*!
61 * \brief Encodes the header information in the given tags into
62 * bits and places them into \p out.
63 *
64 * \details
65 * Uses the following header format:
66 * - Bits 0-11: The packet length (what was stored in the tag with key \p
67 * len_tag_key)
68 * - Bits 12-23: The header number (counts up everytime this function is called)
69 * - Bit 24-31: 8-Bit CRC
70 */
71 bool format(int nbytes_in,
72 const unsigned char* input,
73 pmt::pmt_t& output,
74 pmt::pmt_t& info) override;
75
76 bool parse(int nbits_in,
77 const unsigned char* input,
78 std::vector<pmt::pmt_t>& info,
79 int& nbits_processed) override;
80
81 /*!
82 * Returns the length of the formatted header in bits.
83 */
84 size_t header_nbits() const override;
85
86 /*!
87 * Factory to create an async packet header formatter; returns
88 * an sptr to the object.
89 */
90 static sptr make(const std::vector<std::vector<int>>& occupied_carriers,
91 int n_syms,
92 const std::string& len_key_name = "packet_len",
93 const std::string& frame_key_name = "frame_len",
94 const std::string& num_key_name = "packet_num",
95 int bits_per_header_sym = 1,
96 int bits_per_payload_sym = 1,
97 bool scramble_header = false);
98
99protected:
100 pmt::pmt_t d_frame_key_name; //!< Tag key of the additional frame length tag
101 const std::vector<std::vector<int>>
102 d_occupied_carriers; //!< Which carriers/symbols carry data
103 int d_syms_per_set; //!< Helper variable: Total number of elements in
104 //!< d_occupied_carriers
106 std::vector<uint8_t> d_scramble_mask; //!< Bits are xor'd with this before tx'ing
108
109 /*! Get info from the header; return payload length and package
110 * rest of data in d_info dictionary.
111 */
112 int header_payload() override;
113};
114
115} // namespace digital
116} // namespace gr
117
118#endif /* INCLUDED_DIGITAL_HEADER_FORMAT_OFDM_H */
std::shared_ptr< header_format_base > sptr
Definition: header_format_base.h:114
Header formatter that includes the payload length, packet number, and a CRC check on the header.
Definition: header_format_crc.h:47
Header formatter that includes the payload length, packet number, and a CRC check on the header.
Definition: header_format_ofdm.h:47
int d_syms_per_set
Helper variable: Total number of elements in d_occupied_carriers.
Definition: header_format_ofdm.h:103
size_t header_nbits() const override
std::shared_ptr< header_format_ofdm > sptr
Definition: header_format_ofdm.h:49
header_format_ofdm(const std::vector< std::vector< int > > &occupied_carriers, int n_syms, const std::string &len_key_name="packet_len", const std::string &frame_key_name="frame_len", const std::string &num_key_name="packet_num", int bits_per_header_sym=1, int bits_per_payload_sym=1, bool scramble_header=false)
bool parse(int nbits_in, const unsigned char *input, std::vector< pmt::pmt_t > &info, int &nbits_processed) override
pmt::pmt_t d_frame_key_name
Tag key of the additional frame length tag.
Definition: header_format_ofdm.h:100
int d_bits_per_payload_sym
Definition: header_format_ofdm.h:105
const std::vector< std::vector< int > > d_occupied_carriers
Which carriers/symbols carry data.
Definition: header_format_ofdm.h:102
std::vector< uint8_t > d_scramble_mask
Bits are xor'd with this before tx'ing.
Definition: header_format_ofdm.h:106
static sptr make(const std::vector< std::vector< int > > &occupied_carriers, int n_syms, const std::string &len_key_name="packet_len", const std::string &frame_key_name="frame_len", const std::string &num_key_name="packet_num", int bits_per_header_sym=1, int bits_per_payload_sym=1, bool scramble_header=false)
size_t d_header_len
Definition: header_format_ofdm.h:107
bool format(int nbytes_in, const unsigned char *input, pmt::pmt_t &output, pmt::pmt_t &info) override
Encodes the header information in the given tags into bits and places them into out.
#define DIGITAL_API
Definition: gr-digital/include/gnuradio/digital/api.h:18
GNU Radio logging wrapper for log4cpp library (C++ port of log4j)
Definition: basic_block.h:29
std::shared_ptr< pmt_base > pmt_t
typedef for shared pointer (transparent reference counting).
Definition: pmt.h:84