Apparatuses, systems, and methods for transmitting a preamble. The UE may transmit a preamble to a base station in a random access channel (RACH). The RACH may be located in unlicensed spectrum. The bandwidth of the preamble may cover a majority of a nominal channel bandwidth of the RACH. The UE may receive a random access response and establish a connection with the base station in response to receiving the random access response.

Disclosed are a method for performing a random access and a terminal, the method comprising: acquiring information on a sequence set and information on a phase pattern vector set to be used during a random access step; selecting, from among a plurality of phase pattern vectors included in the phase pattern vector set, any one phase pattern vector corresponding to the repeating transmission frequency of an RACH signal; transmitting, to a base station, the generated RACH signal for a time period up to the repeating transmission frequency by using the selected phase pattern vector and any one sequence selected from among a plurality of sequences included in the sequence set; and receiving, from the base station, an RACH response signal indicating an estimated sequence and an estimated phase pattern vector.

A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal.

A communication system with increased throughput for providing communication between transceivers via a wireless communication channel through multiple, N, single input, single output, SISO, links provided for a corresponding number, N, of data sequences, wherein each transceiver includes a transmitter having spreading units each configured to spread in an operation mode of the communication system a data sequence with an associated predefined unique spreading code sequence to generate a spread data sequence multiplexed to an antenna unit of the respective transceiver configured to transmit the spread data sequences via the wireless communication channel to antenna units of other transceivers of the communication system.

Aspects of the present disclosure provide techniques for variable spreading factor codes for non-orthogonal multiple access (NOMA). In an exemplary method, a base station assigns, from a first codebook of N short code sequences of length K, a subset of the short code sequences to a number of user equipments (UEs); receives a signal including uplink data or control signals from two or more of the UEs, wherein a first uplink data or control signal is sent using a first subsequence of one of the assigned short code sequences, and a second uplink data or control signal is sent using a second subsequence of one of the assigned short code sequences or using one of the assigned short code sequences; and decodes each uplink data or control signal in the signal based on the assigned short code sequences and subsequences of the assigned the short code sequences.

Aspects of the present disclosure provide design that allows for assigning code sequences for UEs for use in RSMA.

A method to disguise existence of a communication channel and/or type of communication method thereby to provide a discrete communication channel and/or protect communicated contents from malevolent manipulations, the method comprising: at a transmitter end, transforming a signal to be transmitted into a noise-like signal without changing the original communication parameters and protocol, and transmitting the noise-like signal; and/or at a receiver end, receiving a noise-like signal and de-spreading the noise-like signal thereby to reconstruct the signal to be transmitted.

A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal.

A network node (700), a wireless device and methods therein for handling radio resources when feedback signalling is employed to indicate either an acknowledgement, ACK, or a non-acknowledgement, NACK, of correct reception of data transmitted by the wireless device. The network node (700) assigns a shared radio resource to a group of wireless devices (702) to be used for retransmission in case the feedback signalling for a transmission of data indicates a NACK. When receiving a set of concurrent transmissions of data from the wireless devices (702) where a subset of the concurrent transmissions of data is not received correctly, the network node (700) transmits a NACK to those wireless devices that transmitted the subset that was not received correctly. The network node (700) then receives on the shared radio resource a retransmission of at least one of the concurrent transmissions of data in the subset that was not received correctly from at least one wireless device to which said NACK was transmitted.

A satellite communications system can use a spread-spectrum waveform and format, a synchronization scheme, and/or a power management algorithm. This approach can provide benefits such as allowing every terminal to communicate with every other terminal, link margin permitting. This gives the network a mesh topology although it can be configured in a star topology for highly asymmetric applications. A further understanding of the nature and the advantages of particular embodiments disclosed herein may be realized by reference of the remaining portions of the specification and the attached drawings.