GNU Radio's CDMA Package
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Default header formatter for digital packet transmission. More...
#include <packet_header2.h>
Public Types | |
typedef boost::shared_ptr< packet_header2 > | sptr |
Public Member Functions | |
packet_header2 (long header_len, const std::string &len_tag_key="packet_len", const std::string &num_tag_key="packet_num", int bits_per_byte=1, int tcm_type=1, const std::string &tcm_type_key="tcm_type") | |
~packet_header2 () | |
void | set_tcm_type (int tcm_type) |
pmt::pmt_t | num_tag_key () |
bool | header_formatter (long packet_len, unsigned char *out, const std::vector< tag_t > &tags=std::vector< tag_t >()) |
Encodes the header information in the given tags into bits and places them into out . | |
Static Public Member Functions | |
static sptr | make (long header_len, const std::string &len_tag_key="packet_len", const std::string &num_tag_key="packet_num", int bits_per_byte=1, int tcm_type=1, const std::string &tcm_tag_key="tcm_type") |
Protected Attributes | |
pmt::pmt_t | d_tcm_tag_key |
int | d_tcm_type |
Default header formatter for digital packet transmission.
For bursty/packetized digital transmission, packets are usually prepended with a packet header, containing the number of bytes etc. This class is not a block, but a tool to create these packet header.
This is a default packet header (see header_formatter()) for a description on the header format). To create other header, derive packet header creator classes from this function.
gr::digital::packet_headergenerator_bb uses header generators derived from this class to create packet headers from data streams.
typedef boost::shared_ptr<packet_header2> gr::cdma::packet_header2::sptr |
gr::cdma::packet_header2::packet_header2 | ( | long | header_len, |
const std::string & | len_tag_key = "packet_len" , |
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const std::string & | num_tag_key = "packet_num" , |
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int | bits_per_byte = 1 , |
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int | tcm_type = 1 , |
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const std::string & | tcm_type_key = "tcm_type" |
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gr::cdma::packet_header2::~packet_header2 | ( | ) |
bool gr::cdma::packet_header2::header_formatter | ( | long | packet_len, |
unsigned char * | out, | ||
const std::vector< tag_t > & | tags = std::vector< tag_t >() |
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Encodes the header information in the given tags into bits and places them into out
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Uses the following header format: Bits 0-11: The packet length (what was stored in the tag with key len_tag_key
) Bits 12-15: The trellis coded modulation type Bits 16-27: The header number (counts up everytime this function is called) Bit 28-35: 8-Bit CRC All other bits: Are set to zero
If the header length is smaller than 36, bits are simply left out. For this reason, they always start with the LSB.
However, it is recommended to stay above 36 Bits, in order to have a working CRC.
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