An apparatus for communication in a wireless communication network comprises a coder that encodes a set of data symbols to produce a set of coded symbols; a modulator that modulates the coded symbols onto a set of subcarrier frequencies to generate a time-domain signal comprising a sum of a set of modulated pulse waveforms; and a transmitter configured for transmitting the time-domain signal in the wireless communication network. The coder employs a matrix of spreading codes, wherein each column of the matrix multiplies a different one of the data symbols, which causes the modulator to produce a corresponding one of the set of modulated pulse waveforms. Each column of the matrix of spreading codes comprises a set of linearly increasing phases, which provides a time offset to the corresponding modulated pulse waveforms.

Acknowledgement feedback is conveyed to a network node for unicast and multicast transmissions received by a wireless device. The wireless device configures uplink control channel resources responsive to an uplink channel format indicated by an uplink channel format indicator. Each possible ACK or NAK combination for the unicast and multicast transmissions maps to a different cyclic shift of a base sequence defined according to the uplink control channel format. The wireless device receives a unicast transmission and a multicast transmission. Further, when in a joint acknowledgement mode, the wireless device configures acknowledgement feedback for the received unicast and multicast transmissions according to the cyclic shift mapping and jointly transmits the acknowledgement feedback for both the received unicast transmission and the received multicast transmission to the network node in an acknowledgement time slot.

Provided is a radio communication device which can make Acknowledgement (ACK) reception quality and Negative Acknowledgement (NACK) reception quality to be equal to each other. The device includes: a scrambling unit (214) which multiplies a response signal after modulated, by a scrambling code “1” or “e.sup.−j(π/2)” so as to rotate a constellation for each of response signals on a cyclic shift axis; a spread unit (215) which performs a primary spread of the response signal by using a Zero Auto Correlation (ZAC) sequence set by a control unit (209); and a spread unit (218) which performs a secondary spread of the response signal after subjected to the primary spread, by using a block-wise spread code sequence set by the control unit (209).

An electronic device may include wireless circuitry. The wireless circuitry may include a quadratic phase generator for outputting a perfectly interpolated constant amplitude zero autocorrelation (CAZAC) sequence for a transmit path. The quadratic phase generator may include a numerically controlled oscillator, a switch controlled based on a value output from the numerically controlled oscillator, a first integrator stage, and a second integrator stage connected in series with the first integrator stage. The numerically controlled oscillator may receive as inputs a chirp count and a word length. The switch may be configured to switchably feed one of two input values that are a function of the chirp count and the word length to the first integrator stage. The quadratic phase generator may output full-bandwidth chirps or reduced-bandwidth chirps. Bandwidth reduction can be achieved by scaling the two input values of the switches.

A method for user localization in a cellular network includes receiving, by a receiver unit, Orthogonal Time Frequency Space (OTFS) modulated Constant-Amplitude-Zero-Autocorrelation (CAZAC) sequences generated and transmitted in a Doppler-delay domain by a transmitter unit. The method further includes estimating, by the receiver unit, Doppler shift and/or relative speed between the transmitter unit and the receiver unit by filtering the received OTFS modulated CAZAC sequences.

A user device communicates in a wireless network by encoding a set of data symbols with a set of complex-valued codes to produce a set of subcarrier values. The subcarrier values are modulated onto a set of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers assigned to the user device to produce a time-domain waveform that comprises a superposition of modulated subcarriers, and the time-domain waveform is transmitted in the wireless network. The set of subcarrier values comprises a first polyphase code that encodes a first of the set of data symbols and at least a second polyphase code that encodes at least a second of the set of data symbols. The first polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a first periodic pulse waveform having a peak value centered at a first time in an OFDM symbol interval, and the second polyphase code causes constructive and destructive interference between the modulated subcarriers to produce a second periodic pulse waveform having a peak value centered at a second time in the OFDM symbol interval, wherein the second time is different from the first time.

Various embodiments relate to spread spectrum communication. A communication system may include a base station and a user equipment. The base station may be configured to: add a cyclic prefix (CP) to each block of a number of blocks of a first direct sequence spread spectrum (DSSS) signal to generate a first cyclic prefix-direct sequence spread spectrum (CP-DSSS) signal; add artificial noise to the first CP-DSSS signal; and transmit, via a channel, the first CP-DSSS signal. The user equipment configured to receive the first CP-DSSS signal. Associated methods and communications systems are also disclosed.

Provided is a radio communication device which can make Acknowledgement (ACK) reception quality and Negative Acknowledgement (NACK) reception quality to be equal to each other. The device includes: a scrambling unit (214) which multiplies a response signal after modulated, by a scrambling code “1” or “e.sup.−j(π/2)” so as to rotate a constellation for each of response signals on a cyclic shift axis; a spread unit (215) which performs a primary spread of the response signal by using a Zero Auto Correlation (ZAC) sequence set by a control unit (209); and a spread unit (218) which performs a secondary spread of the response signal after subjected to the primary spread, by using a block-wise spread code sequence set by the control unit (209).

Methods, systems, and devices for the design of symbol-group based spreading schemes are described. An exemplary method for wireless communication includes transmitting, by a terminal, a first spread signal that is generated by spreading a first group of N data symbols using a first set of N sequences, where N is a symbol-group length, L is a spreading length, each of the first set of N sequences is from an orthogonal spreading sequence set that comprises L sequences, and each of the L sequences is of length L. Another exemplary method for wireless communication includes transmitting, by a network node, an indication of a first set of N sequences, and receiving a first spread signal comprising a group of N data symbols spread using the first set of N sequences.

A method for allocating and processing sequences in a communication system includes: dividing sequences in a sequence group into multiple sub-groups, each sub-group corresponding to its own mode of occupying time frequency resources; selecting sequences from a candidate sequence collection corresponding to each sub-group to form the sequences in the sub-group by: the sequences in a sub-group i in a sequence group k being composed of n sequences in the candidate sequence collection, the n sequences making a |r.sub.i/N.sub.i−c.sub.k/N.sub.p.sub.1| or |(r.sub.i/N.sub.i−c.sub.k/N.sub.p.sub.1) modu m.sub.k,i| function value the smallest, second smallest, till the n.sup.th smallest respectively; allocating the sequence group to cells, users or channels. It prevents the sequences highly correlated with the sequences of a specific length from appearing in other sequence groups.