Aspects of the present disclosure provide design that allows for assigning code sequences for UEs for use in RSMA.

A controller generates a sequence by one of (a) splitting a base sequence into multiple equal-size segments and adding said segments elementwise, and (b) generating several cyclically shifted versions of a base sequence, adding the cyclically shifted versions together, and truncating said cyclically shifted versions.

A method of randomly accessing wireless communication resources in a LTE uplink comprising transmitting, by a user device, a plurality of random access requests wherein each request is transmitted on a different communication channel from a plurality of communication channels and each request comprises a preamble generated using a different root sequence. The method further comprises receiving, at the user device, at least one random access response via the plurality of communication channels; and completing a random access procedure on the communication channel which conveyed the random access response.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may apply one or more spreading sequences to a set of modulation symbols of a data set to generate spread modulation symbols; apply a scrambling sequence to the spread modulation symbols to generate a set of scrambled symbols; and transmit a waveform based at least in part on the set of scrambled symbols. Numerous other aspects are provided.

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).

Certain aspects of the present disclosure provide techniques for wireless communication. A method that may be performed by a base station (BS), the method including determining a plurality of root sets, wherein each root set of the plurality of root sets comprise at least a first root and a second root. In some examples, the method includes transmitting signaling that indicates the plurality of root sets.

A method of randomly accessing wireless communication resources in a LTE uplink comprising transmitting, by a user device, a plurality of random access requests wherein each request is transmitted on a different communication channel from a plurality of communication channels and each request comprises a preamble generated using a different root sequence. The method further comprises receiving, at the user device, at least one random access response via the plurality of communication channels; and completing a random access procedure on the communication channel which conveyed the random access response

Methods, systems, and devices related to applying a spreading code to reference signals are described. In one exemplary aspect, a method for wireless communication includes receiving a message indicating a set of control options available to the mobile device for data transmissions. The method includes selecting a spreading code sequence from a number of spreading code sequences, wherein the spreading code sequence corresponds to a control option in the set of control options, wherein the number of spreading code sequences is greater than a length of each of the spreading code sequence, and wherein the spreading code sequences are generated using a method when the length of each of the spreading code sequences is greater than or equal to a value. The method also includes generating a plurality of reference signal symbols using the spreading code sequence, and transmitting the plurality of reference signal symbols.

Various novel concepts and schemes pertaining to non-orthogonal multiple access for wireless communications are described. A group orthogonal coded access (GOCA) scheme is introduced to reduce multi-user interference (MUI) and improve performance. A repetition division multiple access (RDMA) scheme is introduced to differentiate user equipment (UEs) by different repetition patterns. A low-density spreading (LDS) scheme is introduced to reduce MUI and improve performance.