Systems, methods and instrumentalities are disclosed for superposed signaling for bandwidth efficiency in wireless communications. Homogeneous and heterogeneous signals may be superposed on the same channel. Superposed signals may comprise, for example, multi carrier, frequency division and code division signals, including multiple access, e.g., OFDMA and CDMA, signals. Data for various receivers may be dynamically selected for signal superpositioning, for example, based on radio access technology, communication rate (e.g. high and low rates), distance between transmitter and receiver (e.g. near and far signals). Communication rate and power may be allocated to superposed signals. Interference nulling may be applied, for example, by selecting or excluding spreading codes and/or subcarriers. Nulled locations may be used to transmit critical information. Interference shaping may be applied to modify interference, e.g., by transmitting interference symbols using reserved spreading codes. Support information, e.g., code indices, code length and/or subcarriers, may be signaled to support or optimize performance.

A method for a terminal, in a wireless communication system, receiving a downlink signal from a cell in which a plurality of beams are multiplexed according to an embodiment of the present invention comprises the steps of: generating a quasi-orthogonal scrambling sequence that is used for scrambling the downlink signal; and receiving the downlink signal through one or more beams of the plurality of multiplexed beams using the generated quasi-orthogonal scrambling sequence, wherein the terminal can initialise the quasi-orthogonal scrambling sequence using a beam-specific parameter corresponding to one or more beams for transmitting the downlink signal when generating the quasi-orthogonal scrambling sequence.

One embodiment relates to a method for transmitting a random access preamble in a transmitting sub-frame at a terminal device. The method (200) comprises: creating a random access preamble such that it comprises a plurality of random access sequences (S210); dividing the plurality of random access sequences into a number N.sub.c of groups, each of groups including two or more random access sequences (S220); performing code division multiplexing with respect to the groups of the plurality of random access sequences in a frequency domain, based on an orthogonal cover code selected for the terminal device from a pre-defined code set (S230); and transforming signals after the code division multiplexing into the time domain (S240). There are provided corresponding methods and devices.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may use a lower code rate by splitting a data stream into multiple data sub-streams. The UE may split the data stream to synchronously encode, modulate, and spread the data sub-streams at different layers. Then, the UE may superpose or combine the sub-streams together. The UE may scramble the combined data stream with a UE-specific scrambling code. In some examples, the UE may then apply a cyclic prefix to the combined data stream. The UE may then transmit the combined data stream to a base station. The receiving base station may use layer-wise matched filters and element-wise signal estimators (ESE) to obtain soft information such as log-likelihood ratios. Channel decoders may then determine estimated bits for each layer of each user of the combined data stream.

A technique for allocating transmission bandwidth in a wireless network includes logically organizing transmission resources along a two-dimensional grid of physical resource blocks (PRBs), where each PRB is made up of a first equal number of time slots along a time dimension and a second equal number of subcarriers along a frequency dimension; and allocating PRBs to data transmissions such that locations of PRBs are hopped for successive transmissions within the two-dimensional grid.

Methods, systems, and devices for designing and configuring reference signals in wireless communication systems are disclosed. An example method for wireless communication includes transmitting, by a wireless device to a network node, a sounding reference signal (SRS), where the SRS is determined by a first parameter and a cyclic shift parameter, and a value of the first parameter hops at a level of a first type of time unit and a value of the cyclic shift parameter hops at a level of a second type of time unit. Another example method for wireless communication includes receiving, by a wireless device from a network node, a configuration for an SRS resource, and transmitting an SRS in the SRS resource, where the configuration includes information associated with one or more time-domain orthogonal cover codes (TD-OCC) or a multiplexing type for multiple SRS ports in the SRS resource.

The present disclosure describes the concept of operations and the medium access control protocols of a wireless communication system using code-division multiple access with interference avoidance (CDMA-IA) as its physical layer. The system can dynamically share a common band with other networks without a central radio resource controller. In one embodiment, the wireless communication system includes a plurality of radio nodes forming a wireless mesh network, wherein the pairs of radio nodes use, individually optimized, time division duplexing. At least one radio node includes a software-defined radio, a memory, and an electronic processor. The electronic processor is configured to control the software-defined radio to transmit a pilot signal and share various state information with the other nodes of the network. The shared information includes local spectrum occupancy and node connectivity sets. The pervasive sharing of spectrum occupancy among all nodes enables the usage of the shared band to be maximized.

Certain aspects of the present disclosure relate to communication systems, and more particularly, to single-carrier waveform generation for transmission. An exemplary method generally includes concatenating a first sequence of data samples with samples of a known sequence to generate a first series of samples, performing a discrete Fourier transform (DFT) on the first series of samples to generate a first series of frequency-domain samples, mapping the first series of frequency-domain samples and first zero values to first tones of a system bandwidth, performing an inverse discrete Fourier transform (IDFT) on the mapped first series of frequency-domain samples and the mapped first zero values to generate first time-domain samples of a first orthogonal frequency domain multiplexing (OFDM) symbol, and transmitting the first OFDM symbol as a single-carrier waveform in a first period.

A method for receiving, by a terminal, a signal on the basis of a non-orthogonal multiple access scheme in a wireless communication system comprises the steps of: receiving, from a base station, control information including information on a codebook selected for the terminal among pre-defined codebooks for non-orthogonal multiple access and information on a codeword selected from the selected codebook; receiving, from the base station, data for the terminal according to scheduling of the control information; and detecting data for the terminal by performing a multi-user detection (MUD) scheme on the basis of the information on the selected codebook and the information on the selected codeword.

Various aspects described herein relate to techniques for using orthogonal demodulation reference signals (DMRSs) for downlink control channels in wireless communications systems. In an aspect, a method for a user equipment (UE) includes receiving one or more DMRSs over a multi-symbol downlink control channel. The method may further include identifying a time-first control channel element (CCE)-to-resource element group (REG) mapping for the multi-symbol downlink control channel, and identifying an orthogonal DMRS of the one or more DMRSs based on the time-first CCE-to-REG mapping, and decoding the multi-symbol downlink control channel based on at least the identified orthogonal DMRS.