OFDM Blocks

Classes
class	gr_ofdm_bpsk_demapper
	take a vector of complex constellation points in from an FFT and demodulate to a stream of bits. Simple BPSK version. More...
class	gr::digital::ofdm_frame_equalizer_vcvc
	OFDM frame equalizerThis does two things: First, it removes the coarse carrier offset. If a tag is found on the first item with the key 'ofdm_sync_carr_offset', this is interpreted as the coarse frequency offset in number of carriers. Next, it performs equalization in one or two dimensions on a tagged OFDM frame. The actual equalization is done by a ofdm_frame_equalizer object, outside of the block. More...
class	gr::digital::ofdm_serializer_vcc
	Serializes complex modulations symbols from OFDM sub-carriersThis is the inverse block to the carrier_allocator_cvc. It outputs the complex data symbols as a tagged stream, discarding the pilot symbols. More...
class	gr::digital::packet_header_ofdm
	Header utility for OFDM signals. More...
class	digital_ofdm_carrier_allocator_cvc
	Create frequency domain OFDM symbols from complex values, add pilots.This block turns a stream of complex, scalar modulation symbols into vectors which are the input for an IFFT in an OFDM transmitter. It also supports the possibility of placing pilot symbols onto the carriers. More...
class	digital_ofdm_chanest_vcvc
	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. More...
class	digital_ofdm_cyclic_prefixer
	Adds a cyclic prefix and performs pulse shaping on OFDM symbols.Input: OFDM symbols (in the time domain, i.e. after the IFFT). Optionally, entire frames can be processed. In this case, len_tag_key must be specified which holds the key of the tag that denotes how many OFDM symbols are in a frame. Output: A stream of (scalar) complex symbols, which include the cyclic prefix and the pulse shaping. Note: If complete frames are processed, and rolloff_len is greater than zero, the final OFDM symbol is followed by the delay line of the pulse shaping. More...
class	digital_ofdm_frame_acquisition
	take a vector of complex constellation points in from an FFT and performs a correlation and equalization.This block takes the output of an FFT of a received OFDM symbol and finds the start of a frame based on two known symbols. It also looks at the surrounding bins in the FFT output for the correlation in case there is a large frequency shift in the data. This block assumes that the fine frequency shift has already been corrected and that the samples fall in the middle of one FFT bin. More...
class	digital_ofdm_frame_sink
	Takes an OFDM symbol in, demaps it into bits of 0's and 1's, packs them into packets, and sends to to a message queue sink.NOTE: The mod input parameter simply chooses a pre-defined demapper/slicer. Eventually, we want to be able to pass in a reference to an object to do the demapping and slicing for a given modulation type. More...
class	digital_ofdm_insert_preamble
	insert "pre-modulated" preamble symbols before each payload. More...
class	digital_ofdm_mapper_bcv
	take a stream of bytes in and map to a vector of complex constellation points suitable for IFFT input to be used in an ofdm modulator. Abstract class must be subclassed with specific mapping. More...
class	digital_ofdm_sampler
	does the rest of the OFDM stuff More...
class	digital_ofdm_sync_sc_cfb
	Schmidl & Cox synchronisation for OFDM. More...