# US 10,873,977 B2 · Random access process of an unlicensed cell in a wireless device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,977 B2 - Document ID: US10873977B2 - Status: Granted - Kind: B2 - Application number: 16/570,353 - Filed: 2019-09-13 - Published: 2020-01-02 - Granted: 2020-12-22 - Earliest claimed: 2015-07-05 - Assignees: Ofinno, LLC - Applicants: Ofinno, LLC - Inventors: Esmael Dinan - Web page: https://patentgrep.com/patent/US10873977B2 ## CPC - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/0838: using contention-free random access [CFRA] - H04W 76/27: Transitions between radio resource control [RRC] states - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A wireless device receives a message indicating a maximum counter value. A listen-before-talk (LBT) is performed for transmission of a preamble for a random access (RA) procedure. When a corresponding RA response is not received: a preamble transmission opportunity counter is increased based on the LBT being performed; a preamble transmission counter is increased based on the LBT being successful; the RA procedure is considered unsuccessfully completed in response to the preamble transmission counter reaching the maximum counter value; and the RA procedure is considered unsuccessfully completed in response to the preamble transmission opportunity counter reaching the maximum counter value. ## Claims ### Claim 1 A method comprising: receiving, by a wireless device, a message indicating a maximum counter value; performing a listen-before-talk (LBT) for transmission of a preamble for a random access (RA) procedure; when a corresponding RA response is not received: increasing a preamble transmission opportunity counter based on the LBT being performed; increasing a preamble transmission counter based on the LBT being successful; considering the RA procedure unsuccessfully completed in response to the preamble transmission counter reaching the maximum counter value; and considering the RA procedure unsuccessfully completed in response to the preamble transmission opportunity counter reaching the maximum counter value. ### Claim 2 (depends on 1) The method of claim 1, further comprising setting a preamble power parameter based on the preamble transmission counter. ### Claim 3 (depends on 2) The method of claim 2, further comprising: receiving a control order indicating the transmission of the preamble; in response to receiving the control order: resetting the preamble transmission counter; and resetting the preamble transmission opportunity counter. ### Claim 4 (depends on 3) The method of claim 3, wherein the control order is a physical downlink control channel (PDCCH) comprising a preamble index and a RA mask index. ### Claim 5 (depends on 2) The method of claim 2, further comprising: based on the LBT for transmission of the preamble indicating a clear channel, monitoring a control channel for the corresponding RA response during a RA response window; and based on the LBT for transmission of the preamble indicating a busy channel, not monitoring the control channel for the corresponding RA response. ### Claim 6 (depends on 2) The method of claim 2, further comprising: based on the LBT for transmission of the preamble indicating a clear channel, starting a RA response window timer for monitoring a control channel for the corresponding RA response; and based on the LBT for transmission of the preamble indicating a busy channel, not starting a RAN response window timer for monitoring the control channel for the corresponding RA response. ### Claim 7 (depends on 2) The method of claim 2, further comprising based on the LBT for transmission of the preamble indicating a busy channel: not starting a RAN response window timer for monitoring a control channel for the corresponding RA response; and selecting a RA resource for transmission of the preamble in response to: the preamble transmission counter being lower than the maximum counter value; and the preamble transmission opportunity counter being lower than the maximum counter value. ### Claim 8 (depends on 1) The method of claim 1, further comprising: receiving a control order indicating the transmission of the preamble; in response to receiving the control order: resetting the preamble transmission counter; and resetting the preamble transmission opportunity counter. ### Claim 9 (depends on 8) The method of claim 8, wherein the control order is a physical downlink control channel (PDCCH) comprising a preamble index and a RA mask index. ### Claim 10 (depends on 1) The method of claim 1, wherein the preamble transmission opportunity counter is configured to limit a time duration that the preamble is used for the RA procedure on a cell. ### Claim 11 (depends on 1) The method of claim 1, further comprising: transmitting, by a physical layer, the preamble if the LBT succeeds, otherwise dropping transmission of the preamble; and receiving, by a MAC layer, a power ramping suspension indication from a physical layer when the transmission of the preamble is dropped due to a failure of the LBT. ### Claim 12 (depends on 1) The method of claim 1, further comprising considering the RA procedure successfully completed when the wireless device receives the corresponding RA response. ### Claim 13 (depends on 1) The method of claim 1, wherein the preamble transmission opportunity counter is configured to count a number of transmission opportunities of the preamble. ### Claim 14 (depends on 1) The method of claim 1, further comprising selecting RA resources for the transmission of the preamble based on: the corresponding RA response not being received; the preamble transmission counter being less than the maximum counter value; and the preamble transmission opportunity counter being less than the maximum counter value. ### Claim 15 (depends on 1) The method of claim 1, further comprising monitoring a downlink channel for the corresponding RA response within a RA response window, the corresponding RA response comprising a preamble identifier of the preamble. ### Claim 16 (depends on 1) The method of claim 1, wherein the message further comprises: RA resource information elements of a RA channel (RACH) on a cell; a RA response window information element; and a maximum RA transmission counter information element. ### Claim 17 (depends on 1) The method of claim 1, further comprising transmitting, by a physical layer, the preamble if the LBT succeeds, otherwise dropping transmission of the preamble. ### Claim 18 (depends on 1) The method of claim 1, further comprising: based on the LBT for transmission of the preamble indicating a clear channel, monitoring a control channel for the corresponding RA response during a RA response window; and based on the LBT for transmission of the preamble indicating a busy channel, not monitoring the control channel for the corresponding RA response. ### Claim 19 (depends on 1) The method of claim 1, further comprising: based on the LBT for transmission of the preamble indicating a clear channel, starting a RA response window timer for monitoring a control channel for the corresponding RA response; and based on the LBT for transmission of the preamble indicating a busy channel, not starting a RAN response window timer for monitoring the control channel for the corresponding RA response. ### Claim 20 (depends on 1) The method of claim 1, further comprising based on the LBT for transmission of the preamble indicating a busy channel: not starting a RAN response window timer for monitoring a control channel for the corresponding RA response; and selecting a RA resource for transmission of a preamble in response to: the preamble transmission counter being lower than the maximum counter value; and the preamble transmission opportunity counter being lower than the maximum counter value.