Estimate channel and coarse frequency offset for OFDM from preamblesInput: OFDM symbols (in frequency domain). The first one (or two) symbols are expected to be synchronisation symbols, which are used to estimate the coarse freq offset and the initial equalizer taps (these symbols are removed from the stream). The following n_data_symbols
are passed through unmodified (the actual equalisation must be done elsewhere). Output: The data symbols, without the synchronisation symbols. The first data symbol passed through has two tags: 'ofdm_sync_carr_offset' (integer), the coarse frequency offset as number of carriers, and 'ofdm_sync_eq_taps' (complex vector). Any tags attached to the synchronisation symbols are attached to the first data symbol. All other tags are propagated as expected.
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#include <gnuradio/digital/ofdm_chanest_vcvc.h>
Public Types | |
typedef boost::shared_ptr < ofdm_chanest_vcvc > | sptr |
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enum | { WORK_CALLED_PRODUCE = -2, WORK_DONE = -1 } |
Magic return values from general_work. More... | |
enum | tag_propagation_policy_t { TPP_DONT = 0, TPP_ALL_TO_ALL = 1, TPP_ONE_TO_ONE = 2 } |
Static Public Member Functions | |
static sptr | make (const std::vector< gr_complex > &sync_symbol1, const std::vector< gr_complex > &sync_symbol2, int n_data_symbols, int eq_noise_red_len=0, int max_carr_offset=-1, bool force_one_sync_symbol=false) |
Additional Inherited Members | |
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virtual | ~block () |
unsigned | history () const |
void | set_history (unsigned history) |
void | declare_sample_delay (int which, unsigned delay) |
void | declare_sample_delay (unsigned delay) |
unsigned | sample_delay (int which) const |
bool | fixed_rate () const |
Return true if this block has a fixed input to output rate. More... | |
virtual void | forecast (int noutput_items, gr_vector_int &ninput_items_required) |
Estimate input requirements given output request. More... | |
virtual int | general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) |
compute output items from input items More... | |
virtual bool | start () |
Called to enable drivers, etc for i/o devices. More... | |
virtual bool | stop () |
Called to disable drivers, etc for i/o devices. More... | |
void | set_output_multiple (int multiple) |
Constrain the noutput_items argument passed to forecast and general_work. More... | |
int | output_multiple () const |
bool | output_multiple_set () const |
void | set_alignment (int multiple) |
Constrains buffers to work on a set item alignment (for SIMD) More... | |
int | alignment () const |
void | set_unaligned (int na) |
int | unaligned () const |
void | set_is_unaligned (bool u) |
bool | is_unaligned () const |
void | consume (int which_input, int how_many_items) |
Tell the scheduler how_many_items of input stream which_input were consumed. This function should be called at the end of work() or general_work(), after all processing is finished. More... | |
void | consume_each (int how_many_items) |
Tell the scheduler how_many_items were consumed on each input stream. More... | |
void | produce (int which_output, int how_many_items) |
Tell the scheduler how_many_items were produced on output stream which_output . More... | |
void | set_relative_rate (double relative_rate) |
Set the approximate output rate / input rate. More... | |
double | relative_rate () const |
return the approximate output rate / input rate More... | |
virtual int | fixed_rate_ninput_to_noutput (int ninput) |
Given ninput samples, return number of output samples that will be produced. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this. More... | |
virtual int | fixed_rate_noutput_to_ninput (int noutput) |
Given noutput samples, return number of input samples required to produce noutput. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this. More... | |
uint64_t | nitems_read (unsigned int which_input) |
Return the number of items read on input stream which_input. More... | |
uint64_t | nitems_written (unsigned int which_output) |
Return the number of items written on output stream which_output. More... | |
tag_propagation_policy_t | tag_propagation_policy () |
Asks for the policy used by the scheduler to moved tags downstream. More... | |
void | set_tag_propagation_policy (tag_propagation_policy_t p) |
Set the policy by the scheduler to determine how tags are moved downstream. More... | |
int | min_noutput_items () const |
Return the minimum number of output items this block can produce during a call to work. More... | |
void | set_min_noutput_items (int m) |
Set the minimum number of output items this block can produce during a call to work. More... | |
int | max_noutput_items () |
Return the maximum number of output items this block will handle during a call to work. More... | |
void | set_max_noutput_items (int m) |
Set the maximum number of output items this block will handle during a call to work. More... | |
void | unset_max_noutput_items () |
Clear the switch for using the max_noutput_items value of this block. More... | |
bool | is_set_max_noutput_items () |
Ask the block if the flag is or is not set to use the internal value of max_noutput_items during a call to work. More... | |
void | expand_minmax_buffer (int port) |
long | max_output_buffer (size_t i) |
Returns max buffer size on output port i . More... | |
void | set_max_output_buffer (long max_output_buffer) |
Request limit on max buffer size on all output ports. More... | |
void | set_max_output_buffer (int port, long max_output_buffer) |
Request limit on max buffer size on output port port . More... | |
long | min_output_buffer (size_t i) |
Returns min buffer size on output port i . More... | |
void | set_min_output_buffer (long min_output_buffer) |
Request limit on the mininum buffer size on all output ports. More... | |
void | set_min_output_buffer (int port, long min_output_buffer) |
Request limit on min buffer size on output port port . More... | |
float | pc_noutput_items () |
Gets instantaneous noutput_items performance counter. More... | |
float | pc_noutput_items_avg () |
Gets average noutput_items performance counter. More... | |
float | pc_noutput_items_var () |
Gets variance of noutput_items performance counter. More... | |
float | pc_nproduced () |
Gets instantaneous num items produced performance counter. More... | |
float | pc_nproduced_avg () |
Gets average num items produced performance counter. More... | |
float | pc_nproduced_var () |
Gets variance of num items produced performance counter. More... | |
float | pc_input_buffers_full (int which) |
Gets instantaneous fullness of which input buffer. More... | |
float | pc_input_buffers_full_avg (int which) |
Gets average fullness of which input buffer. More... | |
float | pc_input_buffers_full_var (int which) |
Gets variance of fullness of which input buffer. More... | |
std::vector< float > | pc_input_buffers_full () |
Gets instantaneous fullness of all input buffers. More... | |
std::vector< float > | pc_input_buffers_full_avg () |
Gets average fullness of all input buffers. More... | |
std::vector< float > | pc_input_buffers_full_var () |
Gets variance of fullness of all input buffers. More... | |
float | pc_output_buffers_full (int which) |
Gets instantaneous fullness of which input buffer. More... | |
float | pc_output_buffers_full_avg (int which) |
Gets average fullness of which input buffer. More... | |
float | pc_output_buffers_full_var (int which) |
Gets variance of fullness of which input buffer. More... | |
std::vector< float > | pc_output_buffers_full () |
Gets instantaneous fullness of all output buffers. More... | |
std::vector< float > | pc_output_buffers_full_avg () |
Gets average fullness of all output buffers. More... | |
std::vector< float > | pc_output_buffers_full_var () |
Gets variance of fullness of all output buffers. More... | |
float | pc_work_time () |
Gets instantaneous clock cycles spent in work. More... | |
float | pc_work_time_avg () |
Gets average clock cycles spent in work. More... | |
float | pc_work_time_var () |
Gets average clock cycles spent in work. More... | |
float | pc_work_time_total () |
Gets total clock cycles spent in work. More... | |
float | pc_throughput_avg () |
Gets average throughput. More... | |
void | reset_perf_counters () |
Resets the performance counters. More... | |
void | setup_pc_rpc () |
Sets up export of perf. counters to ControlPort. Only called by the scheduler. More... | |
bool | is_pc_rpc_set () |
Checks if this block is already exporting perf. counters to ControlPort. More... | |
void | no_pc_rpc () |
If the block calls this in its constructor, it's perf. counters will not be exported. More... | |
void | set_processor_affinity (const std::vector< int > &mask) |
Set the thread's affinity to processor core n . More... | |
void | unset_processor_affinity () |
Remove processor affinity to a specific core. More... | |
std::vector< int > | processor_affinity () |
Get the current processor affinity. More... | |
int | active_thread_priority () |
Get the current thread priority in use. More... | |
int | thread_priority () |
Get the current thread priority stored. More... | |
int | set_thread_priority (int priority) |
Set the current thread priority. More... | |
bool | update_rate () const |
void | system_handler (pmt::pmt_t msg) |
the system message handler More... | |
bool | finished () |
returns true when execution has completed due to a message connection More... | |
block_detail_sptr | detail () const |
void | set_detail (block_detail_sptr detail) |
void | notify_msg_neighbors () |
Tell msg neighbors we are finished. More... | |
void | clear_finished () |
Make sure we dont think we are finished. 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) |
virtual bool | message_port_is_hier (pmt::pmt_t port_id) |
virtual bool | message_port_is_hier_in (pmt::pmt_t port_id) |
virtual bool | message_port_is_hier_out (pmt::pmt_t port_id) |
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) |
virtual bool | has_msg_port (pmt::pmt_t which_port) |
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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enum | vcolor { WHITE, GREY, BLACK } |
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block (void) | |
block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature) | |
void | set_fixed_rate (bool fixed_rate) |
void | add_item_tag (unsigned int which_output, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F) |
Adds a new tag onto the given output buffer. More... | |
void | add_item_tag (unsigned int which_output, const tag_t &tag) |
Adds a new tag onto the given output buffer. More... | |
void | remove_item_tag (unsigned int which_input, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F) |
DEPRECATED. Will be removed in 3.8. More... | |
void | remove_item_tag (unsigned int which_input, const tag_t &tag) |
DEPRECATED. Will be removed in 3.8. More... | |
void | get_tags_in_range (std::vector< tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end) |
Given a [start,end), returns a vector of all tags in the range. More... | |
void | get_tags_in_range (std::vector< tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end, const pmt::pmt_t &key) |
Given a [start,end), returns a vector of all tags in the range with a given key. More... | |
void | get_tags_in_window (std::vector< tag_t > &v, unsigned int which_input, uint64_t rel_start, uint64_t rel_end) |
Gets all tags within the relative window of the current call to work. More... | |
void | get_tags_in_window (std::vector< tag_t > &v, unsigned int which_input, uint64_t rel_start, uint64_t rel_end, const pmt::pmt_t &key) |
Operates like gr::block::get_tags_in_window with the ability to only return tags with the specified key . More... | |
void | enable_update_rate (bool en) |
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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::vector< long > | d_max_output_buffer |
std::vector< long > | d_min_output_buffer |
gr::thread::mutex | d_setlock |
gr::logger_ptr | d_logger |
gr::logger_ptr | d_debug_logger |
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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 |
Estimate channel and coarse frequency offset for OFDM from preambles
Input: OFDM symbols (in frequency domain). The first one (or two) symbols are expected to be synchronisation symbols, which are used to estimate the coarse freq offset and the initial equalizer taps (these symbols are removed from the stream). The following n_data_symbols
are passed through unmodified (the actual equalisation must be done elsewhere). Output: The data symbols, without the synchronisation symbols. The first data symbol passed through has two tags: 'ofdm_sync_carr_offset' (integer), the coarse frequency offset as number of carriers, and 'ofdm_sync_eq_taps' (complex vector). Any tags attached to the synchronisation symbols are attached to the first data symbol. All other tags are propagated as expected.
Note: The vector on ofdm_sync_eq_taps is already frequency-corrected, whereas the rest is not.
This block assumes the frequency offset is even (i.e. an integer multiple of 2).
[1] Schmidl, T.M. and Cox, D.C., "Robust frequency and timing synchronization for OFDM", Communications, IEEE Transactions on, 1997. [2] K.D. Kammeyer, "Nachrichtenuebertragung," Chapter. 16.3.2.
typedef boost::shared_ptr<ofdm_chanest_vcvc> gr::digital::ofdm_chanest_vcvc::sptr |
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static |
sync_symbol1 | First synchronisation symbol in the frequency domain. Its length must be the FFT length. For Schmidl & Cox synchronisation, every second sub-carrier has to be zero. |
sync_symbol2 | Second synchronisation symbol in the frequency domain. Must be equal to the FFT length, or zero length if only one synchronisation symbol is used. Using this symbol is how synchronisation is described in [1]. Leaving this empty forces us to interpolate the equalizer taps. If you are using an unusual sub-carrier configuration (e.g. because of OFDMA), this sync symbol is used to identify the active sub-carriers. If you only have one synchronisation symbol, set the active sub-carriers to a non-zero value in here, and also set force_one_sync_symbol parameter to true. |
n_data_symbols | The number of data symbols following each set of synchronisation symbols. Must be at least 1. |
eq_noise_red_len | If non-zero, noise reduction for the equalizer taps is done according to [2]. In this case, it is the channel influence time in number of samples. A good value is usually the length of the cyclic prefix. |
max_carr_offset | Limit the number of sub-carriers the frequency offset can maximally be. Leave this zero to try all possibilities. |
force_one_sync_symbol | See sync_symbol2 . |