This disclosure relates to techniques for synchronization signals. The synchronization signal comprise a primary synchronization signal (PSS) generated based on a PSS sequence and a secondary synchronization signal (SSS) generated based on an SSS sequence. The SSS sequence may be generated based on a first sequence corresponding to a first cyclic shift and a second sequence corresponding to a second cyclic shift. The first cyclic shift and the second cyclic shift are associated with a Cell ID. The PSS sequence may be generated based on one of the first and the second sequences.

A demodulator and method includes a plurality of correlation circuits, a result combining stage, and a time combining stage. The plurality of correlation circuits may be configured to output a plurality of correlation values that indicate a likelihood of whether a pattern of a buffered portion of an input data signal matches a first plurality of target frequency behavior patterns. The plurality of correlation circuits may be further configured to output a plurality of delayed correlation values that indicate a likelihood of whether a pattern of a delayed buffered portion of the input data signal matches a second plurality of target frequency behavior patterns, where both the buffered portion and the delayed buffered portion include a current symbol.

Methods, systems, and devices for wireless communications are described that support pairwise cross correlation sequences for non-orthogonal multiple access wireless communications. A user equipment (UE) may receive, from a base station, an indication of a spreading factor and a number of transmitters in a group of non-orthogonal multiple access (NOMA) transmitters configured for concurrent transmissions. The UE may determine, based on the spreading factor and the number of transmitters, a first spreading sequence of a set of spreading sequences from a first codebook, the first spreading sequence having a defined value for pairwise cross correlation with each spreading sequence of the plurality of spreading sequences. The first UE may identify data to be transmitted in an uplink transmission, apply the first spreading sequence to the data to be transmitted in the uplink transmission, and transmit the uplink transmission to the base station.

A demodulator and method includes a plurality of correlation circuits, a result combining stage, and a time combining stage. The plurality of correlation circuits may be configured to output a plurality of correlation values that indicate a likelihood of whether a pattern of a buffered portion of an input data signal matches a first plurality of target frequency behavior patterns. The plurality of correlation circuits may be further configured to output a plurality of delayed correlation values that indicate a likelihood of whether a pattern of a delayed buffered portion of the input data signal matches a second plurality of target frequency behavior patterns, where both the buffered portion and the delayed buffered portion include a current symbol.

A transmitter stores mappings of distinct values of an information signal to corresponding ones of distinct combinations of K chirps taken from M chirps that are different from each other, such that each of the distinct values is mapped to a corresponding one of the distinct combinations of K chirps. The transmitter receives a distinct value among the distinct values of the information signal. The transmitter selects, based on the mappings, a distinct combination of K chirps among the distinct combinations of K chirps that is mapped to the distinct value. The transmitter sums the K chirps of the distinct combination of K chirps to produce a symbol that represents the distinct value. The transmitter modulates the symbol to produce a modulated symbol, and transmits the modulated symbol. A receiver receives a modulated symbol that conveys a distinct value, and recovers the distinct value using stored mappings.

This disclosure relates to techniques for synchronization signals. The synchronization signal comprise a primary synchronization signal (PSS) generated based on a PSS sequence and a secondary synchronization signal (SSS) generated based on an SSS sequence. The SSS sequence may be generated based on a first sequence corresponding to a first cyclic shift and a second sequence corresponding to a second cyclic shift. The first cyclic shift and the second cyclic shift are associated with Cell ID. The PSS sequence may be generated based on one of the first and the second sequences.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network controller may determine a first set of spreading sequences and a second set of spreading sequences for non-orthogonal multiple access (NOMA) communication, wherein the first set of spreading sequences is different than the second set of spreading sequences; and configure a first cell to use the first set of spreading sequences and a second cell to use the second set of spreading sequences; or configure the first set of spreading sequences to be used for first user equipment associated with a cell center of the first cell and the second set of spreading sequences to be used for second user equipment associated with a cell edge of the first cell or the second cell. Numerous other aspects are provided.

A receiver signal is sampled at a sampling rate equivalent to a chip rate at which chips of a known signal are timed. The resulting receiver signal samples are segmented into receiver signal segments, which are filtered by respective matched filters that are matched to known signal segments segmented from the known signal. Indexes are assigned to elements of the resulting filter response sequences to define an array thereof. Frequency transforms are computed of elements of the filter response sequences in respective columns of the array. Indexes are assigned to elements of the resulting frequency response sequences to define another array thereof. Channel effects imparted on a radio signal are jointly estimated from characteristics of the other array at which at least one local maximum is located.

A communication device, a method of operating a communication device, and a spread-spectrum receiver are disclosed. The method includes receiving an incoming RF signal, demodulating the incoming RF signal to generate a baseband signal, filtering the baseband signal with a normalized matched filter having filter characteristics matched to a pulse-shaping filter of the transmitter that generated the incoming RF signal, and extracting a received signal from a normalized output generated by the normalized matched filter. As a result, interferences and noise from harsh environments may be suppressed.

This disclosure relates to techniques for synchronization signals. The synchronization signal comprise a primary synchronization signal (PSS) generated based on a PSS sequence and a secondary synchronization signal (SSS) generated based on an SSS sequence. The SSS sequence may be generated based on a first sequence corresponding to a first cyclic shift and a second sequence corresponding to a second cyclic shift. The first cyclic shift and the second cyclic shift are associated with Cell ID. The PSS sequence may be generated based on one of the first and the second sequences.