# US 11,122,617 B2 · Two step random access procedure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,617 B2 - Document ID: US11122617B2 - Status: Granted - Kind: B2 - Application number: 16/510,649 - Filed: 2019-07-12 - Published: 2019-11-07 - Granted: 2021-09-14 - Earliest claimed: 2016-11-01 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Renqiu Wang; Wanshi Chen; Hao Xu; Hung Ly; Heechoon Lee - Web page: https://patentgrep.com/patent/US11122617B2 ## CPC - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/0836: with 2-step access - H04W 84/042: {Public Land Mobile systems, e.g. cellular systems} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Wireless communication devices are adapted to facilitate a random access procedure. According to one example, scheduled entity can transmit a first transmission that is received by a scheduling entity. The first transmission may include a physical random access channel (PRACH) preamble sequence and a first message including information for determining a device-specific network identifier for the scheduled entity. The scheduling entity may transmit a second transmission that is received by the scheduled entity. The second transmission may include information on a physical downlink control channel (PDCCH) addressed to the device-specific network identifier for the scheduled entity, and a second message on a physical downlink shared channel (PDSCH). Other aspects, embodiments, and features are also included. ## Claims ### Claim 1 A scheduling entity, comprising: a transceiver; a memory; and a processor communicatively coupled to the transceiver and the memory, the processor configured to: receive via the transceiver a first transmission from a scheduled entity for a random access procedure, the first transmission comprising a physical random access channel (PRACH) preamble sequence and a first message, wherein the scheduled entity is without a device-specific temporary cell-radio network temporary identifier (TC-RNTI) when the first transmission is received and the first message includes information for determining the device-specific TC-RNTI for the scheduled entity, wherein the information for determining the device-specific TC-RNTI for the scheduled entity includes one or more parameters associated with resources utilized to send the first transmission; determine the device-specific TC-RNTI for the scheduled entity based on the received information for determining the device-specific TC-RNTI; detect the PRACH preamble sequence; decode the first message; and in response to successfully detecting the PRACH preamble sequence and decoding the first message of the first transmission, transmit via the transceiver a second transmission including information on a physical downlink control channel (PDCCH) addressed to the device-specific TC-RNTI for the scheduled entity, and a second message on a physical downlink shared channel (PDSCH) associated with the PDCCH. ### Claim 2 (depends on 1) The scheduling entity of claim 1, wherein: the information for determining the device-specific TC-RNTI for the scheduled entity further includes at least a portion of a user equipment identity associated with the scheduled entity; and the processor is further configured to determine the device-specific TC-RNTI based on at least a portion of the user equipment identity and the one or more parameters associated with resources utilized to send the first transmission. ### Claim 3 (depends on 1) The scheduling entity of claim 1, wherein the information on the PDCCH comprises a cyclic redundancy check (CRC) scrambled by the device-specific TC-RNTI for the scheduled entity. ### Claim 4 (depends on 1) The scheduling entity of claim 1, wherein the information on the PDCCH is sent in one of a common search space or a device-specific search space. ### Claim 5 (depends on 1) The scheduling entity of claim 1, wherein the processor is further configured to: receive a retransmission of the first transmission after sending the second transmission; and retransmit the second transmission utilizing at least one of increased resources or a lower coding rate for the PDCCH. ### Claim 6 (depends on 1) The scheduling entity of claim 1, wherein the received first message further includes at least one of a channel flag, a buffer status report (BSR), or a scheduling request (SR). ### Claim 7 (depends on 1) The scheduling entity of claim 1, wherein the transmitted second message on the PDSCH comprises at least one of an indication confirming the PRACH preamble, a timing advance value, a back-off indicator, a contention resolution message, a transmit power control (TPC) command, an uplink resource grant, or a downlink resource grant. ### Claim 8 A method of wireless communication at a scheduling entity, comprising: receiving a first transmission from a scheduled entity for a random access procedure, the first transmission comprising a physical random access channel (PRACH) preamble sequence and a first message, wherein the scheduled entity is without a device-specific temporary cell-radio network temporary identifier (TC-RNTI) when the first transmission is received and the first message includes information for determining the device-specific TC-RNTI for the scheduled entity, wherein the information for determining the device-specific TC-RNTI for the scheduled entity includes one or more parameters associated with resources utilized to send the first transmission; determining the device-specific TC-RNTI for the scheduled entity based on the received information for determining the device-specific TC-RNTI; detecting the PRACH preamble sequence; decoding the first message; and in response to successfully detecting the PRACH preamble sequence and decoding the first message of the first transmission, transmitting a second transmission including information on a physical downlink control channel (PDCCH) addressed to the device-specific TC-RNTI for the scheduled entity, and a second message on a physical downlink shared channel (PDSCH) associated with the PDCCH. ### Claim 9 (depends on 8) The method of claim 8, wherein receiving the first transmission comprising the first message including the information for determining the device-specific TC-RNTI for the scheduled entity further comprises: receiving the first transmission comprising the first message including at least a portion of a user equipment identity associated with the scheduled entity; and further comprising determining the device-specific TC-RNTI based on at least a portion of the user equipment identity and the one or more parameters associated with resources utilized to send the first transmission. ### Claim 10 (depends on 8) The method of claim 8, wherein transmitting the second transmission including information on the PDCCH addressed to the device-specific-TC-RNTI for the scheduled entity comprises: transmitting the PDCCH including a cyclic redundancy check (CRC) scrambled by the device-specific TC-RNTI for the scheduled entity. ### Claim 11 (depends on 8) The method of claim 8, wherein transmitting the second transmission including information on the PDCCH comprises: transmitting the second transmission including information on the PDCCH in one of a common search space or a device-specific search space. ### Claim 12 (depends on 8) The method of claim 8, further comprising: after transmitting the second transmission, receiving a retransmission of the first transmission; and transmitting the second transmission a second time utilizing at least one of increased resources or a lower coding rate for the PDCCH. ### Claim 13 A scheduled entity, comprising: a transceiver; a memory; and a processor communicatively coupled to the transceiver and the memory, the processor configured to: select a physical random access channel (PRACH) preamble sequence from a set of available preamble sequences; transmit via the transceiver a first transmission for a random access procedure without a device-specific temporary cell-radio network temporary identifier (TC-RNTI), the first transmission comprising the PRACH preamble sequence and information for determining the device-specific TC-RNTI for the scheduled entity, wherein the information for determining the device-specific TC-RNTI for the scheduled entity includes one or more parameters associated with resources utilized to send the first transmission; determine the device-specific TC-RNTI for the scheduled entity based on the transmitted information for determining the device-specific TC-RNTI; and receive via the transceiver a second transmission including information on a physical downlink control channel (PDCCH) addressed to the determined device-specific TC-RNTI for the scheduled entity, and a second message on a physical downlink shared channel (PDSCH) associated with the PDCCH. ### Claim 14 (depends on 13) The scheduled entity of claim 13, wherein the information on the PDCCH comprises a cyclic redundancy check (CRC) scrambled by the device-specific TC-RNTI for the scheduled entity. ### Claim 15 (depends on 13) The scheduled entity of claim 13, wherein the information on the PDCCH is received in one of a common search space or a device-specific search space. ### Claim 16 (depends on 13) The scheduled entity of claim 13, wherein the processor is further configured to: save the second message received on the PDSCH after failing to decode the second message; send a negative acknowledgement (NACK); receive a retransmission of the second message on the PDSCH; and utilize both the saved second message received on the PDSCH and the retransmitted second message on the PDSCH to decode the second message received on the PDSCH. ### Claim 17 (depends on 13) The scheduled entity of claim 13, wherein the transmitted first transmission further includes at least one of a channel flag, a buffer status report (BSR), or a scheduling request (SR). ### Claim 18 (depends on 13) The scheduled entity of claim 13, wherein the second message received on the PDSCH comprises at least one of an indication confirming the PRACH preamble, a timing advance value, a back-off indicator, a contention resolution message, a transmit power control (TPC) command, an uplink resource grant, or a downlink resource grant. ### Claim 19 A method of wireless communication at a scheduled entity, comprising: selecting a physical random access channel (PRACH) preamble sequence from a set of available preamble sequences; transmitting a first transmission for a random access procedure without a device-specific temporary cell-radio network temporary identifier (TC-RNTI), the first transmission comprising the PRACH preamble sequence and a first message, wherein the first message includes information for determining the device-specific TC-RNTI for the scheduled entity, wherein the information for determining the device-specific TC-RNTI for the scheduled entity includes one or more parameters associated with resources utilized to send the first transmission; determining the device-specific TC-RNTI for the scheduled entity based on the transmitted information for determining the device-specific TC-RNTI; and receiving a second transmission including information on a physical downlink control channel (PDCCH) addressed to the determined device-specific TC-RNTI for the scheduled entity, and a second message on a physical downlink shared channel (PDSCH) associated with the PDCCH. ### Claim 20 (depends on 19) The method of claim 19, wherein receiving the second transmission including the information on the PDCCH comprises: receiving a cyclic redundancy check (CRC) scrambled by the device-specific TC-RNTI for the scheduled entity. ### Claim 21 (depends on 19) The method of claim 19, wherein receiving the second transmission including the information on the PDCCH comprises: receiving the second transmission including the information on the PDCCH in one of a common search space or a device-specific search space. ### Claim 22 (depends on 19) The method of claim 19, further comprising: failing to decode the second message on the PDSCH; saving the second message received on the PDSCH; sending a negative acknowledgement (NACK); receiving a retransmission of the second message on the PDSCH; and utilizing both the saved second message received on the PDSCH and the retransmitted second message on the PDSCH to decode the second message on the PDSCH. ### Claim 23 (depends on 19) The method of claim 19, wherein transmitting the first transmission comprising the first message comprises: transmitting the first transmission comprising the first message further including at least one of a channel flag, a buffer status report (BSR), or a scheduling request (SR). ### Claim 24 (depends on 19) The method of claim 19, wherein receiving the second transmission including the second message on the PDSCH comprises: receiving the second transmission including the second message on the PDSCH comprising at least one of an indication confirming the PRACH preamble, a timing advance value, a back-off indicator, a contention resolution message, a transmit power control (TPC) command, an uplink resource grant, or a downlink resource grant. ### Claim 25 (depends on 13) The scheduled entity of claim 13, wherein the information for determining the device-specific TC-RNTI for the scheduled entity further includes a portion of a user equipment identity associated with the scheduled entity. ### Claim 26 (depends on 19) The method of claim 19, wherein transmitting the first transmission comprising the first message including the information for determining a device-specific TC-RNTI for the scheduled entity further comprises: transmitting the first transmission comprising a portion of a user equipment identity associated with the scheduled entity.