Random access channel and associated uplink data channel structure construction

A non-transitory computer-readable storage medium storing computer instructions, which when executed by one or more computer processors, cause the one or more computer processors to:

• aggregate a plurality of physical random access (PRACH) preambles into a preamble group based on radio resource control (RRC) signaling received by a wireless device, the preamble group indicating a configuration of a physical uplink shared channel (PUSCH) used for communication between the wireless device and a base station;
• determine a size of the preamble group using at least one of a ceiling operation or a floor operation performed on a number of contention-based preambles and a number of preamble groups used for a two-step random access channel (RACH);
• select a first PRACH preamble from the preamble group;
• encode a message comprising the first PRACH preamble and a payload carried by the PUSCH, the configuration of the PUSCH comprising parameters for decoding the message;
• and
• transmit the message to the base station, wherein the base station decodes the message based on the parameters of the configuration of the PUSCH indicated by the preamble group.

A method comprising:

• receiving, by a wireless device via radio resource control (RRC) signaling, information indicative of a plurality of physical random access (PRACH) preambles;
• determining a preamble group that includes at least a subset of the plurality of PRACH preambles, the preamble group indicating a configuration of a physical uplink shared channel (PUSCH) used for communication between the wireless device and a base station;
• determining, by the wireless device, a size of the preamble group using at least one of a ceiling operation or a floor operation performed on a number of contention-based preambles and a number of preamble groups used for a two-step random access channel (RACH);
• selecting, by the wireless device, a first PRACH preamble from the preamble group;
• encoding, by the wireless device, a message comprising the first PRACH preamble and a payload carried by the PUSCH, the configuration of the PUSCH comprising parameters for decoding the message;
• and
• transmitting, by the wireless device, the message to the base station, wherein the base station decodes the message based on the parameters of the configuration of the PUSCH indicated by the preamble group.