gr::digital::mpsk_receiver_cc Class Reference

This block takes care of receiving M-PSK modulated signals through phase, frequency, and symbol synchronization. More...

#include <gnuradio/digital/mpsk_receiver_cc.h>

Public Types
typedef boost::shared_ptr < mpsk_receiver_cc >	sptr
Public Types inherited from gr::block
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 }

Public Member Functions
virtual float	modulation_order () const =0
	Returns the modulation order (M) currently set. More...
virtual float	theta () const =0
	Returns current value of theta. More...
virtual float	mu () const =0
	Returns current value of mu. More...
virtual float	omega () const =0
	Returns current value of omega. More...
virtual float	gain_mu () const =0
	Returns mu gain factor. More...
virtual float	gain_omega () const =0
	Returns omega gain factor. More...
virtual float	gain_omega_rel () const =0
	Returns the relative omega limit. More...
virtual void	set_modulation_order (unsigned int M)=0
	Sets the modulation order (M) currently. More...
virtual void	set_theta (float theta)=0
	Sets value of theta. More...
virtual void	set_mu (float mu)=0
	Sets value of mu. More...
virtual void	set_omega (float omega)=0
	Sets value of omega and its min and max values. More...
virtual void	set_gain_mu (float gain_mu)=0
	Sets value for mu gain factor. More...
virtual void	set_gain_omega (float gain_omega)=0
	Sets value for omega gain factor. More...
virtual void	set_gain_omega_rel (float omega_rel)=0
	Sets the relative omega limit and resets omega min/max values. More...
Public Member Functions inherited from gr::block
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. 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)
	Sets max buffer size on all output ports. More...
void	set_max_output_buffer (int port, long max_output_buffer)
	Sets 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)
	Sets min buffer size on all output ports. More...
void	set_min_output_buffer (int port, long min_output_buffer)
	Sets 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...
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...
Public Member Functions inherited from gr::basic_block
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)
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...
Public Member Functions inherited from gr::msg_accepter
	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...
Public Member Functions inherited from gr::messages::msg_accepter
	msg_accepter ()
Public Member Functions inherited from gr::blocks::control_loop
	control_loop (void)
	control_loop (float loop_bw, float max_freq, float min_freq)
virtual	~control_loop ()
void	update_gains ()
	Update the system gains from the loop bandwidth and damping factor. More...
void	advance_loop (float error)
	Advance the control loop based on the current gain settings and the inputted error signal. More...
void	phase_wrap ()
	Keep the phase between -2pi and 2pi. More...
void	frequency_limit ()
	Keep the frequency between d_min_freq and d_max_freq. More...
virtual void	set_loop_bandwidth (float bw)
	Set the loop bandwidth. More...
void	set_damping_factor (float df)
	Set the loop damping factor. More...
void	set_alpha (float alpha)
	Set the loop gain alpha. More...
void	set_beta (float beta)
	Set the loop gain beta. More...
void	set_frequency (float freq)
	Set the control loop's frequency. More...
void	set_phase (float phase)
	Set the control loop's phase. More...
void	set_max_freq (float freq)
	Set the control loop's maximum frequency. More...
void	set_min_freq (float freq)
	Set the control loop's minimum frequency. More...
float	get_loop_bandwidth () const
	Returns the loop bandwidth. More...
float	get_damping_factor () const
	Returns the loop damping factor. More...
float	get_alpha () const
	Returns the loop gain alpha. More...
float	get_beta () const
	Returns the loop gain beta. More...
float	get_frequency () const
	Get the control loop's frequency estimate. More...
float	get_phase () const
	Get the control loop's phase estimate. More...
float	get_max_freq () const
	Get the control loop's maximum frequency. More...
float	get_min_freq () const
	Get the control loop's minimum frequency. More...

Static Public Member Functions
static sptr	make (unsigned int M, float theta, float loop_bw, float fmin, float fmax, float mu, float gain_mu, float omega, float gain_omega, float omega_rel)
	Make a M-PSK receiver block. More...

Additional Inherited Members
Protected Types inherited from gr::basic_block
enum	vcolor { WHITE, GREY, BLACK }
Protected Member Functions inherited from gr::block
	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)
	Removes a tag from the given input buffer. More...
void	remove_item_tag (unsigned int which_input, const tag_t &tag)
	Removes a tag from the given input buffer. 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)
Protected Member Functions inherited from gr::basic_block
	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)
Protected Attributes inherited from gr::block
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
Protected Attributes inherited from gr::basic_block
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
Protected Attributes inherited from gr::blocks::control_loop
float	d_phase
float	d_freq
float	d_max_freq
float	d_min_freq
float	d_damping
float	d_loop_bw
float	d_alpha
float	d_beta

Detailed Description

This block takes care of receiving M-PSK modulated signals through phase, frequency, and symbol synchronization.

It performs carrier frequency and phase locking as well as symbol timing recovery. It works with (D)BPSK, (D)QPSK, and (D)8PSK as tested currently. It should also work for OQPSK and PI/4 DQPSK.

The phase and frequency synchronization are based on a Costas loop that finds the error of the incoming signal point compared to its nearest constellation point. The frequency and phase of the NCO are updated according to this error. There are optimized phase error detectors for BPSK and QPSK, but 8PSK is done using a brute-force computation of the constellation points to find the minimum.

The symbol synchronization is done using a modified Mueller and Muller circuit from the paper:

"G. R. Danesfahani, T. G. Jeans, "Optimisation of modified Mueller and Muller algorithm," Electronics Letters, Vol. 31, no. 13, 22 June 1995, pp. 1032 - 1033."

This circuit interpolates the downconverted sample (using the NCO developed by the Costas loop) every mu samples, then it finds the sampling error based on this and the past symbols and the decision made on the samples. Like the phase error detector, there are optimized decision algorithms for BPSK and QPKS, but 8PSK uses another brute force computation against all possible symbols. The modifications to the M&M used here reduce self-noise.

Member Typedef Documentation

typedef boost::shared_ptr<mpsk_receiver_cc> gr::digital::mpsk_receiver_cc::sptr

Member Function Documentation

virtual float gr::digital::mpsk_receiver_cc::gain_mu ( ) const

pure virtual

Returns mu gain factor.

virtual float gr::digital::mpsk_receiver_cc::gain_omega ( ) const

pure virtual

Returns omega gain factor.

virtual float gr::digital::mpsk_receiver_cc::gain_omega_rel ( ) const

pure virtual

Returns the relative omega limit.

static sptr gr::digital::mpsk_receiver_cc::make ( unsigned int  M, float  theta, float  loop_bw, float  fmin, float  fmax, float  mu, float  gain_mu, float  omega, float  gain_omega, float  omega_rel  )

static

Make a M-PSK receiver block.

Parameters

M	modulation order of the M-PSK modulation
theta	any constant phase rotation from the real axis of the constellation
loop_bw	Loop bandwidth to set gains of phase/freq tracking loop
fmin	minimum normalized frequency value the loop can achieve
fmax	maximum normalized frequency value the loop can achieve
mu	initial parameter for the interpolator [0,1]
gain_mu	gain parameter of the M&M error signal to adjust mu (~0.05)
omega	initial value for the number of symbols between samples (~number of samples/symbol)
gain_omega	gain parameter to adjust omega based on the error (~omega^2/4)
omega_rel	sets the maximum (omega*(1+omega_rel)) and minimum (omega*(1+omega_rel)) omega (~0.005)

The constructor also chooses which phase detector and decision maker to use in the work loop based on the value of M.

virtual float gr::digital::mpsk_receiver_cc::modulation_order ( ) const

pure virtual

Returns the modulation order (M) currently set.

virtual float gr::digital::mpsk_receiver_cc::mu ( ) const

pure virtual

Returns current value of mu.

virtual float gr::digital::mpsk_receiver_cc::omega ( ) const

pure virtual

Returns current value of omega.

virtual void gr::digital::mpsk_receiver_cc::set_gain_mu ( float  gain_mu )

pure virtual

Sets value for mu gain factor.

virtual void gr::digital::mpsk_receiver_cc::set_gain_omega ( float  gain_omega )

pure virtual

Sets value for omega gain factor.

virtual void gr::digital::mpsk_receiver_cc::set_gain_omega_rel ( float  omega_rel )

pure virtual

Sets the relative omega limit and resets omega min/max values.

virtual void gr::digital::mpsk_receiver_cc::set_modulation_order ( unsigned int  M )

pure virtual

Sets the modulation order (M) currently.

virtual void gr::digital::mpsk_receiver_cc::set_mu ( float  mu )

pure virtual

Sets value of mu.

virtual void gr::digital::mpsk_receiver_cc::set_omega ( float  omega )

pure virtual

Sets value of omega and its min and max values.

virtual void gr::digital::mpsk_receiver_cc::set_theta ( float  theta )

pure virtual

Sets value of theta.

virtual float gr::digital::mpsk_receiver_cc::theta ( ) const

pure virtual

Returns current value of theta.

---

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

• mpsk_receiver_cc.h