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.

Measuring an end-to-end delay(s) in a distributed communications system (DCS) is disclosed. The DCS is coupled to a signal source(s) supporting multiple logical channels and includes multiple remote units each communicating in one or more of the logical channels. The DCS is configured to measure an end-to-end delay(s), which includes a path delay(s) between the signal source and the remote units and a local delay(s) at each of the remote units, for each of the logical channels. The measured end-to-end delay(s) can help the signal source to more accurately determine an equivalent coverage range of the DCS, thus making it possible to generate random access preambles for the DCS based on as few Zadoff-Chu (ZC) sequences as possible. By generating the random access preambles based on fewer ZC sequences, it is possible to minimize interference among the random access preambles, thus helping to improve random access performance in the DCS.

A terminal includes a decoder to decode a downlink control channel transmitted on one or more control channel element(s) (CCE(s)) in a search space including a plurality of CCEs. Processing circuitry in the terminal determines an uplink channel resource index based on the one or more CCEs, the uplink channel resource index having an association with a first uplink channel transmission spreading sequence and a second different uplink channel transmission spreading sequence. A transmitter transmits a response signal on an uplink channel using the first and second uplink channel transmission spreading sequences.

The invention relates to a client device (100) and a network access node (300) for transmitting and receiving a random access preamble. The modulation sequence for the random access preamble is based on a first sequence and a second sequence. The first sequence is a sequence from a set of near-orthogonal sequences and the second sequence is a sequence from a set of constant envelope sequences. Due to its construction, the random access preamble herein provides low PAPR and suppresses the side-lobes in its auto-correlation function while producing a set of preambles with low cross-correlation. Furthermore, the invention also relates to corresponding methods and a computer program.

Methods, systems, and devices for wireless communications are described. A device (e.g., a base station or a user equipment (UE)) may identify a sequence length corresponding to a number of resource blocks, and select a modulation scheme based on the sequence length. The device may select, from a set of sequences associated with the modulation scheme, a sequence having the sequence length. In some examples, the set of sequences may include at least one of a set of time domain phase shift keying computer-generated sequences or a set of frequency domain phase shift keying computer-generated sequences. The device may generate a reference signal for a data transmission based on the sequence and transmit the reference signal within the number of resource blocks.

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.

A terminal includes a decoder to decode a downlink control channel transmitted on one or more control channel element(s) (CCE(s)) in a search space including a plurality of CCEs. Processing circuitry in the terminal determines an uplink channel resource index based on the one or more CCEs, the uplink channel resource index having an association with a first uplink channel transmission spreading sequence and a second different uplink channel transmission spreading sequence. A transmitter transmits a response signal on an uplink channel using the first and second uplink channel transmission spreading sequences.

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.

Methods, systems, and devices for wireless communications are described. A device (e.g., a base station or a user equipment (UE)) may identify a sequence length corresponding to a number of resource blocks, and select a modulation scheme based on the sequence length. The device may select, from a set of sequences associated with the modulation scheme, a sequence having the sequence length. In some examples, the set of sequences may include at least one of a set of time domain phase shift keying computer-generated sequences or a set of frequency domain phase shift keying computer-generated sequences. The device may generate a reference signal for a data transmission based on the sequence and transmit the reference signal within the number of resource blocks.

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.