Schmidl & Cox synchronisation for OFDM. More...
#include <gnuradio/digital/ofdm_sync_sc_cfb.h>
Public Types | |
typedef boost::shared_ptr < ofdm_sync_sc_cfb > | sptr |
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typedef basic_block_sptr | opaque_self |
typedef for object returned from self(). More... | |
Static Public Member Functions | |
static sptr | make (int fft_len, int cp_len, bool use_even_carriers=false) |
Additional Inherited Members | |
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virtual | ~hier_block2 () |
opaque_self | self () |
Return an object, representing the current block, which can be passed to connect. More... | |
void | connect (basic_block_sptr block) |
Add a stand-alone (possibly hierarchical) block to internal graph. More... | |
void | connect (basic_block_sptr src, int src_port, basic_block_sptr dst, int dst_port) |
Add gr-blocks or hierarchical blocks to internal graph and wire together. More... | |
void | msg_connect (basic_block_sptr src, pmt::pmt_t srcport, basic_block_sptr dst, pmt::pmt_t dstport) |
Add gr-blocks or hierarchical blocks to internal graph and wire together. More... | |
void | msg_connect (basic_block_sptr src, std::string srcport, basic_block_sptr dst, std::string dstport) |
void | msg_disconnect (basic_block_sptr src, pmt::pmt_t srcport, basic_block_sptr dst, pmt::pmt_t dstport) |
void | msg_disconnect (basic_block_sptr src, std::string srcport, basic_block_sptr dst, std::string dstport) |
void | disconnect (basic_block_sptr block) |
Remove a gr-block or hierarchical block from the internal flowgraph. More... | |
void | disconnect (basic_block_sptr src, int src_port, basic_block_sptr dst, int dst_port) |
Disconnect a pair of gr-blocks or hierarchical blocks in internal flowgraph. More... | |
void | disconnect_all () |
Disconnect all connections in the internal flowgraph. More... | |
virtual void | lock () |
virtual void | unlock () |
int | max_output_buffer (size_t port=0) |
Returns max buffer size (itemcount) on output port i . More... | |
void | set_max_output_buffer (int max_output_buffer) |
Sets max buffer size (itemcount) on all output ports. More... | |
void | set_max_output_buffer (size_t port, int max_output_buffer) |
Sets max buffer size (itemcount) on output port port . More... | |
int | min_output_buffer (size_t port=0) |
Returns min buffer size (itemcount) on output port i . More... | |
void | set_min_output_buffer (int min_output_buffer) |
Sets min buffer size (itemcount) on all output ports. More... | |
void | set_min_output_buffer (size_t port, int min_output_buffer) |
Sets min buffer size (itemcount) on output port port . More... | |
flat_flowgraph_sptr | flatten () const |
hier_block2_sptr | to_hier_block2 () |
bool | has_msg_port (pmt::pmt_t which_port) |
bool | message_port_is_hier (pmt::pmt_t port_id) |
bool | message_port_is_hier_in (pmt::pmt_t port_id) |
bool | message_port_is_hier_out (pmt::pmt_t port_id) |
void | message_port_register_hier_in (pmt::pmt_t port_id) |
void | message_port_register_hier_out (pmt::pmt_t port_id) |
void | set_processor_affinity (const std::vector< int > &mask) |
Set the affinity of all blocks in hier_block2 to processor core n . More... | |
void | unset_processor_affinity () |
Remove processor affinity for all blocks in hier_block2. More... | |
std::vector< int > | processor_affinity () |
Get the current processor affinity. More... | |
bool | all_min_output_buffer_p (void) |
Get if all block min buffers should be set. More... | |
bool | all_max_output_buffer_p (void) |
Get if all block max buffers should be set. More... | |
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pmt::pmt_t | message_subscribers (pmt::pmt_t port) |
virtual | ~basic_block () |
long | unique_id () const |
long | symbolic_id () const |
std::string | name () const |
std::string | symbol_name () const |
gr::io_signature::sptr | input_signature () const |
gr::io_signature::sptr | output_signature () const |
basic_block_sptr | to_basic_block () |
bool | alias_set () |
std::string | alias () |
pmt::pmt_t | alias_pmt () |
void | set_block_alias (std::string name) |
void | message_port_register_in (pmt::pmt_t port_id) |
void | message_port_register_out (pmt::pmt_t port_id) |
void | message_port_pub (pmt::pmt_t port_id, pmt::pmt_t msg) |
void | message_port_sub (pmt::pmt_t port_id, pmt::pmt_t target) |
void | message_port_unsub (pmt::pmt_t port_id, pmt::pmt_t target) |
pmt::pmt_t | message_ports_in () |
Get input message port names. More... | |
pmt::pmt_t | message_ports_out () |
Get output message port names. More... | |
void | _post (pmt::pmt_t which_port, pmt::pmt_t msg) |
bool | empty_p (pmt::pmt_t which_port) |
is the queue empty? More... | |
bool | empty_p () |
bool | empty_handled_p (pmt::pmt_t which_port) |
are all msg ports with handlers empty? More... | |
bool | empty_handled_p () |
size_t | nmsgs (pmt::pmt_t which_port) |
How many messages in the queue? More... | |
void | insert_tail (pmt::pmt_t which_port, pmt::pmt_t msg) |
pmt::pmt_t | delete_head_nowait (pmt::pmt_t which_port) |
pmt::pmt_t | delete_head_blocking (pmt::pmt_t which_port, unsigned int millisec=0) |
msg_queue_t::iterator | get_iterator (pmt::pmt_t which_port) |
void | erase_msg (pmt::pmt_t which_port, msg_queue_t::iterator it) |
const msg_queue_map_t & | get_msg_map (void) const |
virtual void | setup_rpc () |
Set up the RPC registered variables. More... | |
bool | is_rpc_set () |
Ask if this block has been registered to the RPC. More... | |
void | rpc_set () |
When the block is registered with the RPC, set this. More... | |
virtual bool | check_topology (int ninputs, int noutputs) |
Confirm that ninputs and noutputs is an acceptable combination. More... | |
template<typename T > | |
void | set_msg_handler (pmt::pmt_t which_port, T msg_handler) |
Set the callback that is fired when messages are available. More... | |
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msg_accepter () | |
~msg_accepter () | |
void | post (pmt::pmt_t which_port, pmt::pmt_t msg) |
send msg to msg_accepter on port which_port More... | |
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pmt::pmt_t | hier_message_ports_in |
pmt::pmt_t | hier_message_ports_out |
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enum | vcolor { WHITE, GREY, BLACK } |
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hier_block2 (void) | |
hier_block2 (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature) | |
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basic_block (void) | |
basic_block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature) | |
Protected constructor prevents instantiation by non-derived classes. More... | |
void | set_input_signature (gr::io_signature::sptr iosig) |
may only be called during constructor More... | |
void | set_output_signature (gr::io_signature::sptr iosig) |
may only be called during constructor More... | |
void | set_color (vcolor color) |
Allow the flowgraph to set for sorting and partitioning. More... | |
vcolor | color () const |
virtual bool | has_msg_handler (pmt::pmt_t which_port) |
Tests if there is a handler attached to port which_port . More... | |
virtual void | dispatch_msg (pmt::pmt_t which_port, pmt::pmt_t msg) |
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std::string | d_name |
gr::io_signature::sptr | d_input_signature |
gr::io_signature::sptr | d_output_signature |
long | d_unique_id |
long | d_symbolic_id |
std::string | d_symbol_name |
std::string | d_symbol_alias |
vcolor | d_color |
bool | d_rpc_set |
msg_queue_map_t | msg_queue |
std::vector< boost::any > | d_rpc_vars |
pmt::pmt_t | d_message_subscribers |
Schmidl & Cox synchronisation for OFDM.
Input: complex samples. Output 0: Fine frequency offset, scaled by the OFDM symbol duration. This is in [1]. The normalized frequency offset is then 2.0*output0/fft_len. Output 1: Beginning of the first OFDM symbol after the first (doubled) OFDM symbol. The beginning is marked with a 1 (it's 0 everywhere else).
The evaluation of the coarse frequency offset is not done in this block. Also, the initial equalizer taps are not calculated here.
Note that we use a different normalization factor in the timing metric than the authors do in their original work[1]. If the timing metric (8) is
we calculate the normalization as
i.e., we estimate the energy from both half-symbols. This avoids spurious detects at the end of a burst, when the energy level suddenly drops.
[1] Schmidl, T.M. and Cox, D.C., "Robust frequency and timing synchronization for OFDM", Communications, IEEE Transactions on, 1997.
typedef boost::shared_ptr<ofdm_sync_sc_cfb> gr::digital::ofdm_sync_sc_cfb::sptr |
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static |
fft_len | FFT length |
cp_len | Length of the guard interval (cyclic prefix) in samples |
use_even_carriers | If true, the carriers in the sync preamble are occupied such that the even carriers are used (0, 2, 4, ...). If you use all carriers, that would include the DC carrier, so be careful. |