A transmitting UE may in a device-to-device (D2D) communication may identify a demodulation reference signal (DMRS) sequence for a D2D transmission based at least in part on a subset of bits of a sidelink control information (SCI) transmission. The subset of bits of the SCI transmission may be selected such that the bits have sufficient variability to reduce the likelihood that multiple UEs may use the same DMRS sequence. The subset of bits of the SCI transmission may be all or a portion of a cyclic redundancy check (CRC) for the SCI.

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.

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.

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 /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.

Provided is a method for detecting whether a random access channel (RACH) preamble collision occurs in a wireless communication system. An evolved Node B (eNB) receives, from a first user equipment (UE), a first RACH preamble generated by using a combination of a plurality of sequences, and also receives, from a second UE, a second RACH preamble generated by using one sequence. The eNB detects whether a collision occurs between the first RACH preamble and the second RACH preamble on the basis of the received patterns of the first RACH preamble and the second RACH preamble, wherein the received patterns of the first RACH preamble and the second RACH preamble are based on channel delay caused by multiple paths.

A method of facilitating a user equipment (UE) communicating with a base station (BS) via a cell of a mobile communications system is disclosed. The UE selects a random access preamble (RAP) from a set of RAPs and transmits the RAP to the BS. The BS receives the RAP and estimates a time of arrival of the RAP. A pre-defined set is used in generating the set of RAPs via at least one Zadoff-Chu sequence. The pre-defined set includes all of the following values: 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419.

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 technique includes multiplying, by a user device, a first uplink control information, associated with a first control channel format length, with a first orthogonal signal to obtain a first spread control signal, multiplying, by the user device, a second uplink control information, associated with a second control channel format length, with a second orthogonal signal that is different than the first orthogonal signal to obtain a second spread control signal, the second control channel format length being different than the first control channel format length, receiving, by the user device, a first resource grant indicating one or more resource blocks for uplink transmission, the first resource grant associated with or provided for the first uplink control information, and transmitting, by the user device, at least partially simultaneously via the one or more resource blocks, the first spread control signal and the second spread control signal.

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 includes the steps of setting a standard sequence with a standard sequence length (Nb) and a standard sequence number (rb) in a step (ST101), setting a threshold value (Xth(m)) in accordance with an RB number (m) in a step (ST103), setting a sequence length (N) corresponding to RB number (m) in a step (ST104), judging whether r/Nrb/Nb=Xth(m) is satisfied in a step (ST106), including a plurality of Zadoff-Chu sequences with a sequence number (r) and a sequence length (N) in a sequence group (rb) in a step (ST107) if the judgment is positive, and allocating the sequence group (rb) to the same cell in a step (ST112).

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 includes the steps of setting a standard sequence with a standard sequence length (Nb) and a standard sequence number (rb) in a step (ST101), setting a threshold value (Xth(m)) in accordance with an RB number (m) in a step (ST103), setting a sequence length (N) corresponding to RB number (m) in a step (ST104), judging whether r/Nrb/Nb=Xth(m) is satisfied in a step (ST106), including a plurality of Zadoff-Chu sequences with a sequence number (r) and a sequence length (N) in a sequence group (rb) in a step (ST107) if the judgment is positive, and allocating the sequence group (rb) to the same cell in a step (ST112).