# US 12,114,363 B2 · Methods for balancing resources utilized in random-access procedures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,114,363 B2 - Document ID: US12114363B2 - Status: Granted - Kind: B2 - Application number: 17/765,111 - Filed: 2020-11-05 - Published: 2022-12-01 - Granted: 2024-10-08 - Earliest claimed: 2019-11-07 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Krishna Chitti; Andreas Cedergren; Robert Mark Harrison; Zhipeng Lin; Jonas Sedin - Web page: https://patentgrep.com/patent/US12114363B2 ## CPC - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/004: {in the uplink, i.e. towards network} - H04W 74/0836: with 2-step access - H04W 74/0838: using contention-free random access [CFRA] - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Embodiments include methods for user equipment (UE) random access to a cell in a wireless network. Such methods include selecting one of a plurality of available random-access preambles and mapping the selected random-access preamble to one of a plurality of available physical uplink shared channel (PUSCH) resource units (PRUs) based on a mapping constraint. In the mapping constraint, one or more of the available PRUs are not used for the mapping and an integer number of the available random-access preambles are mapped to each of the available PRUs that are used for the mapping. Such methods also include transmitting the selected random-access preamble on a random access channel (RACH) and transmitting a data message on the PRU mapped to the selected random-access preamble. Other embodiments include complementary methods for a network node, as well as UEs and network nodes configured to perform such methods. ## Claims ### Claim 1 A method for user equipment (UE) random access to a cell in a wireless network, the method comprising: selecting one of a plurality of available random-access preambles; mapping the selected random-access preamble to one of a plurality of available physical uplink shared channel (PUSCH) resource units (PRUs) based on a mapping constraint that comprises: one or more of the available PRUs are not used for the mapping, and an integer number of the available random-access preambles are mapped to each of the available PRUs that are used for the mapping; transmitting the selected random-access preamble on a random access channel (RACH); and transmitting a data message on the PRU to which the selected random-access preamble is mapped. ### Claim 2 (depends on 1) The method of claim 1, wherein: the available random-access preambles are arranged into a plurality of first groups; the available PRUs are arranged into a plurality of second groups; and the mapping constraint includes a one-to-one mapping between the first groups and the second groups. ### Claim 3 (depends on 2) The method of claim 2, wherein selecting one of the available random-access preambles comprises: selecting one of the first groups based on a UE measurement of downlink signal quality; and randomly selecting a random-access preamble from the selected first group. ### Claim 4 (depends on 1) The method of claim 1, wherein: the mapping constraint is associated with a mapping period; and during the mapping period, the available PRUs that are not used for the mapping occur after the available PRUs that are used for the mapping. ### Claim 5 (depends on 1) The method of claim 1, wherein at least one of the following depends on whether frequency hopping is enabled for the PUSCH: how many of the available PRUs are not used for the mapping; and the integer number of the available random-access preambles mapped to each of the available PRUs that are used for the mapping. ### Claim 6 (depends on 1) The method of claim 1, wherein the data message is transmitted on the PRU to which the selected random-access preamble is mapped, using one or more of the following: a lower power level relative to power levels for other available PRUs; a UE-specific spatial filter; and a UE-specific scrambling code. ### Claim 7 (depends on 1) The method of claim 1, wherein the data message is transmitted on the PRU to which the selected random-access preamble is mapped without receiving a response, from the wireless network, to the transmission of the selected random-access preamble. ### Claim 8 (depends on 1) A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment, UE configured for random access to a cell in a wireless network, configure the UE to perform operations corresponding to the method of claim 1. ### Claim 9 A method for a network node to facilitate user equipment (UE) random access to a cell in a wireless network, the method comprising: detecting a random-access preamble transmitted by a UE on a random access channel (RACH); mapping the detected random-access preamble to one of a plurality of available physical uplink shared channel (PUSCH) resource units (PRUs) based on a mapping constraint that comprises: one or more of the available PRUs are not used for the mapping, and an integer number of the available random-access preambles are mapped to each of the available PRUs that are used for the mapping; and receiving a data message transmitted by the UE on the PRU to which the detected random-access preamble is mapped. ### Claim 10 (depends on 9) The method of claim 9, wherein: the available random-access preambles are arranged into a plurality of first groups; the available PRUs are arranged into a plurality of second groups; and the mapping constraint includes a one-to-one mapping between the first groups and the second groups. ### Claim 11 (depends on 10) The method of claim 10, wherein the detected random-access preamble is from a particular one of the first groups that is associated with a particular downlink signal quality measured by the UE. ### Claim 12 (depends on 9) The method of claim 9, wherein: the mapping constraint is associated with a mapping period; and during the mapping period, the available PRUs that are not used for the mapping occur after the available PRUs that are used for the mapping. ### Claim 13 (depends on 9) The method of claim 9, wherein at least one of the following depends on whether frequency hopping is enabled for the PUSCH: how many of the available PRUs are not used for the mapping; and the integer number of the available random-access preambles mapped to each of the available PRUs that are used for the mapping. ### Claim 14 (depends on 9) The method of claim 9, wherein the data message is received on the PRU to which the detected random-access preamble is mapped, according to one or more of the following: a lower power level relative to power levels for other available PRUs; a UE-specific spatial filter; and a UE-specific scrambling code. ### Claim 15 (depends on 9) The method of claim 9, wherein the data message is received on the PRU to which the detected random-access preamble is mapped without transmitting, to the UE, a response to the detected random-access preamble. ### Claim 16 (depends on 9) A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a network node configured to facilitate user equipment (UE) random access to a cell in a wireless network, configure the network node to perform operations corresponding to the method of claim 9. ### Claim 17 A user equipment (UE) configured for random access to a cell in a wireless network, the UE comprising: radio transceiver circuitry configured to communicate with a network node serving the cell; and processing circuitry operatively coupled to the radio transceiver circuitry, whereby the processing circuitry and the radio transceiver circuitry are configured to: select one of a plurality of available random-access preambles; map the selected random-access preamble to one of a plurality of available physical uplink shared channel (PUSCH) resource units (PRUs) based on a mapping constraint that comprises: one or more of the available PRUs are not used for the mapping, and an integer number of the available random-access preambles are mapped to each of the available PRUs that are used for the mapping; transmit the selected random-access preamble on a random access channel (RACH); and transmit a data message on the PRU to which the selected random-access preamble is mapped. ### Claim 18 (depends on 17) The UE of claim 17, wherein: the available random-access preambles are arranged into a plurality of first groups; the available PRUs are arranged into a plurality of second groups; and the mapping constraint includes a one-to-one mapping between the first groups and the second groups. ### Claim 19 (depends on 18) The UE of claim 18, wherein the processing circuitry and the radio transceiver circuitry are configured to select one of the available random-access preambles based on: selecting one of the first groups based on a UE measurement of downlink signal quality; and randomly selecting a random-access preamble from the selected first group. ### Claim 20 (depends on 17) The UE of claim 17, wherein: the mapping constraint is associated with a mapping period; and during the mapping period, the available PRUs that are not used for the mapping occur after the available PRUs that are used for the mapping. ### Claim 21 (depends on 17) The UE of claim 17, wherein at least one of the following depends on whether frequency hopping is enabled for the PUSCH: how many of the available PRUs are not used for the mapping; and the integer number of the available random-access preambles mapped to each of the available PRUs that are used for the mapping. ### Claim 22 A network node configured to facilitate user equipment (UE) random access to a cell in a wireless network, the network node comprising: radio network interface circuitry configured to communicate with UEs; and processing circuitry operatively coupled to the radio network interface circuitry, whereby the processing circuitry and the radio network interface circuitry are configured to: detect a random-access preamble transmitted by a UE on a random access channel (RACH); map the detected random-access preamble to one of a plurality of available physical uplink shared channel (PUSCH) resource units (PRUs) based on a mapping constraint that comprises: one or more of the available PRUs are not used for the mapping, and an integer number of the available random-access preambles are mapped to each of the available PRUs that are used for the mapping; and receive a data message transmitted by the UE on the PRU to which the detected random-access preamble is mapped. ### Claim 23 (depends on 22) The network node of claim 22, wherein: the available random-access preambles are arranged into a plurality of first groups; the available PRUs are arranged into a plurality of second groups; and the mapping constraint includes a one-to-one mapping between the first groups and the second groups. ### Claim 24 (depends on 22) The network node of claim 22, wherein: the mapping constraint is associated with a mapping period; and during the mapping period, the available PRUs that are not used for the mapping occur after the available PRUs that are used for the mapping. ### Claim 25 (depends on 22) The network node of claim 22, wherein at least one of the following depends on whether frequency hopping is enabled for the PUSCH: how many of the available PRUs are not used for the mapping; and the integer number of the available random-access preambles mapped to each of the available PRUs that are used for the mapping.