Header formatter that includes the payload length, packet number, and a CRC check on the header. More...

#include <gnuradio/digital/header_format_ofdm.h>

Public Member Functions
	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)

virtual	~header_format_ofdm ()

virtual bool	format (int nbytes_in, const unsigned char *input, pmt::pmt_t &output, pmt::pmt_t &info)
	Encodes the header information in the given tags into bits and places them into `out`. More...

virtual bool	parse (int nbits_in, const unsigned char *input, std::vector< pmt::pmt_t > &info, int &nbits_processed)

virtual size_t	header_nbits () const

Public Member Functions inherited from gr::digital::header_format_crc
	header_format_crc (const std::string &len_key_name="packet_len", const std::string &num_key_name="packet_num")

virtual	~header_format_crc ()

void	set_header_num (unsigned header_num)

Public Member Functions inherited from gr::digital::header_format_base
	header_format_base ()

virtual	~header_format_base ()

sptr	base ()

sptr	formatter ()

size_t	header_nbytes () const

Static Public Member Functions
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)

Static Public Member Functions inherited from gr::digital::header_format_crc
static sptr	make (const std::string &len_key_name="packet_len", const std::string &num_key_name="packet_num")

Protected Member Functions
virtual int	header_payload ()

Protected Member Functions inherited from gr::digital::header_format_crc
virtual bool	header_ok ()
	Verify that the header is valid. More...

Protected Member Functions inherited from gr::digital::header_format_base
virtual void	enter_search ()
	Enter Search state of the state machine to find the access code. More...

virtual void	enter_have_sync ()
	Access code found, start getting the header. More...

virtual void	enter_have_header (int payload_len)
	Header found, setup for pulling in the hard decision bits. More...

Protected Attributes
pmt::pmt_t	d_frame_key_name
	Tag key of the additional frame length tag. More...

const std::vector< std::vector< int > >	d_occupied_carriers
	Which carriers/symbols carry data. More...

int	d_syms_per_set
	Helper variable: Total number of elements in d_occupied_carriers. More...

int	d_bits_per_payload_sym

std::vector< uint8_t >	d_scramble_mask
	Bits are xor'd with this before tx'ing. More...

size_t	d_header_len

Protected Attributes inherited from gr::digital::header_format_crc
uint16_t	d_header_number

pmt::pmt_t	d_len_key_name

pmt::pmt_t	d_num_key_name

boost::crc_optimal< 8, 0x07, 0xFF, 0x00, false, false >	d_crc_impl

Protected Attributes inherited from gr::digital::header_format_base
state_t	d_state
	state of the state machine More...

header_buffer	d_hdr_reg
	header_buffer object to hold header bits More...

pmt::pmt_t	d_info
	info captured from the header More...

gr::logger_ptr	d_logger

gr::logger_ptr	d_debug_logger

Additional Inherited Members
Public Types inherited from gr::digital::header_format_base
typedef boost::shared_ptr< header_format_base >	sptr

Protected Types inherited from gr::digital::header_format_base
enum	state_t { STATE_SYNC_SEARCH, STATE_HAVE_SYNC }

Detailed Description

Header formatter that includes the payload length, packet number, and a CRC check on the header.

Child class of header_format_base. This version's header format looks like:

length (12 bits): length of the payload
number (12 bits): packet number
CRC8 (8 bits): A CRC8 check on the header contents

Instead of duplicating the payload length, we only add it once and use the CRC8 to make sure it's correctly received.

  |  0 -- 11 | 12 -- 23 | 24 -- 31 |
  |    len   | pkt len  |   CRC8   |

Reimplements packet_header_default in the style of the header_format_base.

Constructor & Destructor Documentation

gr::digital::header_format_ofdm::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`
	)

virtual gr::digital::header_format_ofdm::~header_format_ofdm ( )

virtual

Member Function Documentation

virtual bool gr::digital::header_format_ofdm::format	(	int	nbytes_in,
		const unsigned char *	input,
		pmt::pmt_t &	output,
		pmt::pmt_t &	info
	)

virtual

Encodes the header information in the given tags into bits and places them into out.

Uses the following header format:

Bits 0-11: The packet length (what was stored in the tag with key len_tag_key)
Bits 12-23: The header number (counts up everytime this function is called)
Bit 24-31: 8-Bit CRC

Reimplemented from gr::digital::header_format_crc.

virtual size_t gr::digital::header_format_ofdm::header_nbits ( ) const

virtual

Returns the length of the formatted header in bits.

Reimplemented from gr::digital::header_format_crc.

virtual int gr::digital::header_format_ofdm::header_payload ( )

protectedvirtual

Get info from the header; return payload length and package rest of data in d_info dictionary.

Reimplemented from gr::digital::header_format_crc.

static sptr gr::digital::header_format_ofdm::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`
	)

static

Factory to create an async packet header formatter; returns an sptr to the object.

virtual bool gr::digital::header_format_ofdm::parse	(	int	nbits_in,
		const unsigned char *	input,
		std::vector< pmt::pmt_t > &	info,
		int &	nbits_processed
	)

virtual

Parses a header. This function is overloaded in the child class, which knows how to convert the incoming hard bits (0's and 1's) back into a packet header.

Parameters

nbits_in	The number of bits in the input array.
input	The input as hard decision bits.
info	A vector of pmt::dicts to hold any meta data or info about the PDU. When parsing the header, the formatter can add info from the header into this dict. Each packet has a single PMT dictionary of info, so the vector length is the number of packets received extracted during one call to this parser function.
nbits_processed	Number of input bits actually processed; If all goes well, this is nbits_in. A premature return after a bad header could be less than this.

MUST be overloaded.

Reimplemented from gr::digital::header_format_crc.

Member Data Documentation

int gr::digital::header_format_ofdm::d_bits_per_payload_sym

protected

pmt::pmt_t gr::digital::header_format_ofdm::d_frame_key_name

protected

Tag key of the additional frame length tag.

size_t gr::digital::header_format_ofdm::d_header_len

protected

const std::vector<std::vector<int> > gr::digital::header_format_ofdm::d_occupied_carriers

protected

Which carriers/symbols carry data.

std::vector<uint8_t> gr::digital::header_format_ofdm::d_scramble_mask

protected

Bits are xor'd with this before tx'ing.

int gr::digital::header_format_ofdm::d_syms_per_set

protected

Helper variable: Total number of elements in d_occupied_carriers.

The documentation for this class was generated from the following file:

header_format_ofdm.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation