TECHNICAL FIELD

The teachings in accordance with the exemplary embodiments of this invention relate generally to a Random Access Channel (RACH) resource allocation and, more specifically, relate to a Random Access Channel (RACH) resource allocation for a repetition transmission mode and association to Synchronization Signal and PBCH blocks (SS/PBCH).

BACKGROUND

This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:

CB Channel Bandwidth

CORESET Control Resource Set

CSI-RS Channel State Information Reference Signal

DCI Downlink Control Information

DMRS Demodulation Reference Signal

DRS Discovery Reference Signal

FDM Frequency Division Multiplexing

gNB 5G Node B

LBT Listen-Before-Talk

MCS Modulation and Coding Scheme

PBCH Physical Broadcast Channel

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PRB Physical Resource Block

PSS Primary Synchronization Signal

QCL Quasi Co-Location

RACH Random Access Channel

RE Resource Element

RO RACH Occasion

RMSI Remaining Minimum System Information

SLIV Start and Length Indicator Value

SSB Synchronization Signal and PBCH Block

SSS Secondary Synchronization Signal

TDM Time Division Multiplexing

TDRA Time Domain Resource Allocation

UE User Equipment

Random access in wireless systems are used to initiate and facilitate communication between user equipment (UE) and a network. The UE and the network which may include a base station (BS) interact for the random access, and to provide wireless communication services for the UE. Such random access procedures enables a UE to extract timing and frequency and/or phase information for timing and frequency synchronization.

Example embodiments of the invention at least work to improve such random access procedures in radio technologies including new radio (NR) radio technologies.

SUMMARY

Various aspects of examples of the invention are set out in the claims.

According to a first aspect of the present invention, a method comprising: receiving, by a user equipment of a communication network, information comprising a random access channel configuration and a number of cycled beams; determining a number of random access channel occasions for a random access channel occasion group; transforming synchronization signal blocks to a beam index given the number of cycled beams and associating beams with the number of random access channel occasions of the random access channel occasion group; identifying a random access channel occasion group associated with the beam index; selecting at least one preamble associated with the beam index in the random access channel occasion group; and transmitting the at least one preamble within each of the number of random access channel occasions of the random access channel occasion group to perform a random access channel procedure.

According to a second aspect of the present invention, an apparatus comprising: at least one processor; and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least: receive information comprising a random access channel configuration and a number of cycled beams; determine a number of random access channel occasions for a random access channel occasion group; transform synchronization signal blocks to a beam index given the number of cycled beams and associate beams with the number of random access channel occasions of the random access channel occasion group; identify a random access channel occasion group associated with the beam index; select at least one preamble associated with the beam index in the random access channel occasion group; and transmit the at least one preamble within each of the number of random access channel occasions of the random access channel occasion group to perform a random access channel procedure.

According to a third aspect of the present invention, A non-transitory computer storage medium encoded with a computer program, the program comprising instructions that when executed by one or more computers cause the one or more computers to perform operations comprising: receiving information comprising a random access channel configuration and a number of cycled beams; determining a number of random access channel occasions for a random access channel occasion group; transforming synchronization signal blocks to a beam index given the number of cycled beams and associating beams with the number of random access channel occasions of the random access channel occasion group; identifying a random access channel occasion group associated with the beam index; selecting at least one preamble associated with the beam index in the random access channel occasion group; and transmitting the at least one preamble within each of the number of random access channel occasions of the random access channel occasion group to perform a random access channel procedure.

According to a fourth aspect of the present invention, an apparatus comprising: means for receiving information comprising a random access channel configuration and a number of cycled beams; means for determining a number of random access channel occasions for a random access channel occasion group; means for transforming synchronization signal blocks to a beam index given the number of cycled beams and associating beams with the number of random access channel occasions of the random access channel occasion group; means for identifying a random access channel occasion group associated with the beam index; means for selecting at least one preamble associated with the beam index in the random access channel occasion group; and means for transmitting the at least one preamble within each of the number of random access channel occasions of the random access channel occasion group to perform a random access channel procedure.

