Methods, systems, and devices for wireless communications are described. A transmitting device may identify a set of allocated resource blocks and a number of the allocated resource blocks. The transmitting device may determine a bit sequence length corresponding to the number of allocated resource blocks. The transmitting device may generate a reference signal based on a bit sequence having the bit sequence length and transmit the reference signal within the allocated resource blocks. The transmitting device may modulate the bit sequence using a π/2 binary phase shift keying modulation scheme. The transmitting device may modulate a data bit sequence using the same modulation scheme to generate a modulated data bit sequence, where a peak to average power ratio (PAPR) of tones transporting the modulated data bit sequence satisfies a PAPR threshold and a PAPR of tones transporting the reference signal also satisfies the PAPR threshold.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may communicate with a base station by initiating a random access procedure with a multi-root preamble. The UE may receive, from the base station, a configuration message that indicates one or more parameters for the multi-root preamble. The one or more parameters may include cyclic shifts, phase rotations, and sequence roots corresponding to a plurality of sequences. The base station may identify the one or more parameters and transmit the configuration message based on the identifying. The UE may identify the one or more parameters for the multi-root preamble based on the configuration message and/or a pre-configuration at the UE. The UE may transmit, to the base station, the multi-root preamble based at least in part on the one or more parameters.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may communicate with a base station by initiating a random access procedure with a two-root preamble. The UE may receive, from the base station, control signaling that indicates a set of root preamble sequences. The UE may transmit, to the base station, a preamble signal that is generated based on a first root preamble sequence and a second root preamble sequence of the set of root preamble sequences. The UE may then monitor for a preamble response based on the preamble signal. In some cases, the base station may be a base station in a terrestrial network. In other cases, the base station may be a satellite in a non-terrestrial network (NTN).

Methods, systems, and devices for wireless communications are described that provide for concurrent reference signal transmissions using common resources, such as demodulation reference signal (DMRS) transmissions, from a number of non-orthogonal multiple access (NOMA) transmitters. Different transmitters may use different sequences for reference signal transmissions, which may allow a receiver, such as a wireless base station, to decode the reference signal transmissions for each NOMA transmitter and perform channel estimation for each NOMA transmitter. The reference signal transmissions may be asynchronous with a bounded timing offset or quasi-synchronous, and the reference signal sequence selection may provide for relatively reliable channel estimation and coherent demodulation.

In one aspect, a method includes: iteratively, for each of a plurality of code maps each formed based on one of a plurality of base spreading codes: determining, in a computing system, a plurality of metrics for the code map; and computing, in the computing system, a weighted sum for the code map based on at least some of the plurality of metrics. After this iterative operation, a first base spreading code associated with the weighted sum having an optimal value may be selected. This first base spreading code may be used to configure one or more wireless devices with the first base spreading code to cause the one or more wireless devices to communicate coded symbols using the first base spreading code.

A communication method performed by a base station in a wireless communication network is disclosed. The base station notifies a terminal of a cyclic shift increment N.sub.CS configuration information indicating an N.sub.CS value. The base station then receives from the terminal a random access preamble related to the N.sub.CS value indicated by the N.sub.CS configuration information. The N.sub.CS value belongs to a set of cyclic shift increments including all of the following cyclic shift increments of 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, and 419.

It is an object to provide a sequence allocating method that, while maintaining the number of Zadoff-Chu sequences to compose a sequence group, is configured to make it possible to reduce correlations between different sequential groups. This method comprises the steps of setting a standard sequence with a standard sequence length and a standard sequence number in a step, setting a threshold value in accordance with an RB number in a step, setting a sequence length corresponding to RB number in a step, judging whether r/N-rb/Nb=Xth(m) is satisfied in a step, including a plurality of Zadoff-Chu sequences with a sequence number and a sequence length in a sequence group in a step if the judgment is positive, and allocating the sequence group to the same cell in a step.

It is possible to provide a radio communication terminal device and a radio transmission method which can improve reception performance of a CQI and a reference signal. A phase table storage unit stores a phase table which correlates the amount of cyclic shift to complex coefficients {w1, w2} to be multiplied on the reference signal. A complex coefficient multiplication unit reads out a complex coefficient corresponding to the amount of cyclic shift indicated by resource allocation information, from the phase table storage unit and multiplies the read-out complex coefficient on the reference signal so as to change the phase relationship between the reference signals in a slot.

A communication method performed by a base station in a wireless communication network is disclosed. The base station notifies a terminal of a cyclic shift increment N.sub.CS configuration information indicating an N.sub.CS value. The base station then receives from the terminal a random access preamble related to the N.sub.CS value indicated by the N.sub.CS configuration information. The N.sub.CS value belongs to a set of cyclic shift increments including all of the following cyclic shift increments of 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419.

An embodiment of the present invention discloses a signal sending method, a signal receiving method, a terminal device, a base station, and a system, to ensure that a signal has a sufficiently large capacity when a PAPR is low, and reduce power consumption of the terminal device. The method in embodiments of the present invention includes: generating, by the terminal device, a first signal; performing, by the terminal device, code division processing on the first signal using a target code division sequence selected from a code division sequence set, to generate a second signal, where any two code division sequences in the code division sequence set meet orthogonality and shift orthogonality; and sending, by the terminal device, the second signal to the base station at a corresponding time-frequency resource location.