A wireless communications method synchronously transmits periodically from synchronized base stations of a single frequency network a common downlink synchronization signal (IoT-PSS) that underlays broadcasted signals transmitted in licensed bands of a cellular system, and a system frame number least significant bits signal (IoT-SFN-LSB) indicating timing of transmission of a system information block signal (IoT-SIB) that contains information related to downlink and uplink transmission schedules and allocations. An IoT device receives the common downlink synchronization signal and transmits uplink data only after receiving the synchronization signal and system frame number signal.

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 is configured to receive the first CP-DSSS signal. Associated methods and communications systems are also disclosed.

A wireless communication terminal apparatus wherein even when a SC-FDMA signal is divided into a plurality of clusters and the plurality of clusters are then mapped to respective discontinuous frequency bands (when C-SC-FDMA is used), the improvement effect of system throughput can be maintained, while the user throughput can be improved. In the apparatus, a DFT unit (210) subjects a symbol sequence of time domain to a DFT process, thereby generating signals of frequency domain. A setting unit (211) divides the signals input from the DFT unit (210) into a plurality of clusters according to a cluster pattern that is in accordance with an MCS set, an encoding size, or the number of Ranks occurring during MIMO transmissions, which is indicated in those signals input, and then maps the plurality of clusters to the respective ones of a plurality of discontinuous frequency resources, thereby setting a constellation of the plurality of clusters in the frequency domain.

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(?/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).

A user terminal apparatus includes a receiver to receive control information, and a data processor, coupled to the receiver, to select a sequence from a subset of different sequences. The difference sequences are based on a base sequence, and the subset of different sequences depends on the control information. The different sequences are respectively associated with different message sizes or different radio conditions at the user terminal apparatus, have different cyclic shifts, and are arranged in an order of increasing cyclic shift. A transmitter, coupled to the data processor, transmits the selected sequence.

Transmission of random access preamble structures within a cellular wireless network is based on the use of cyclic shifted constant amplitude zero autocorrelation (CAZAC) sequences to generate the random access preamble signal. A pre-defined set of sequences is arranged in a specific order. Within the predefined set of sequences is an ordered group of sequences that is a proper subset of the pre-defined set of sequences. Within a given cell, up to 64 sequences may need to be signaled. In order to minimize the associated overhead due to signaling multiple sequences, only one logical index is transmitted by a base station serving the cell and a user equipment within the cell derives the subsequent indexes according to the pre-defined ordering. Each sequence has a unique logical index. The ordering of sequences is identified by the logical indexes of the sequences, with each logical index uniquely mapped to a generating index. When a UE needs to transmit, it produces a second sequence using the received indication of the logical index of the first sequence and an auxiliary parameter and then produces a transmission signal by modulating the second sequence.

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(?/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 and apparatuses pertaining to opportunistic peak-to-average power ratio reduction in multi-user multi-input and multi-output (MU-MIMO) wireless communication are described. A method may involve determining whether a length of a payload of each spatial stream of a plurality of spatial streams is less than a predetermined length for transmission of each spatial stream of the plurality of spatial streams. The method may also involve padding one or more time slots associated with a first spatial stream of the plurality of spatial streams with one or more special symbols other than zero in response to a determination that the length of a first payload of the first spatial stream is less than the predetermined length. The method may further involve transmitting the first spatial stream which includes the first payload and the one or more special symbols.

In a radio communication system using OCC for DMRS, a base station apparatus correctly receives PUSCH. If a first mode is set in which a demodulation reference signal of a physical uplink shared channel is multiplied by an orthogonal code determined in advance or if a temporary C-RNTI was used for a transmission of downlink control information, the demodulation reference signal of the physical uplink shared channel is multiplied by the orthogonal code determined in advance, and if a second mode is set in which the demodulation reference signal of the physical uplink shared channel is multiplied by an orthogonal code determined on the basis of cyclic shift information in the downlink control information and moreover, if an RNTI other than the temporary C-RNTI was used for the transmission of the downlink control information, the demodulation reference signal of the physical uplink shared channel is multiplied by the orthogonal code determined on the basis of the cyclic shift information in the downlink control information.

In orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) systems, a wireless transmit/receive unit (WTRU) selects a random access channel (RACH) and a phase for a constant amplitude zero auto correlation (CAZAC) sequence for RACH transmission. The WTRU then transmits a RACH transmission to a Node B via the selected RACH. Once the RACH transmission is detected, the Node B sends an acknowledgement (ACK) to the WTRU over an ACK channel. The Node B may transmit the ACK on a shared channel. The WTRU may ramp up transmit power while the RACH transmission is transmitted, or steps up transmit power of a subsequent RACH transmission. The RACH transmission and data transmission may be either time multiplexed or frequency multiplexed. A plurality of RACHs may be defined and one of the defined RACHs may be selected randomly or based on predetermined criteria.