# US 2021/0345448 A1 · Medium access control protocol data unit in a message 3 buffer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0345448 A1 - Document ID: US20210345448A1 - Status: Published application - Kind: A1 - Application number: 17/375,956 - Filed: 2021-07-14 - Published: 2021-11-04 - Earliest claimed: 2018-09-10 - Assignees: Lenovo (Singapore) Pte. Ltd. - Applicants: Lenovo (Singapore) PTE. LTD. - Inventors: Joachim Loehr; Prateek Basu Mallick; Ravi Kuchibhotla - Web page: https://patentgrep.com/patent/US20210345448A1 ## CPC - H04W 80/02: Data link layer protocols - H04L 1/1822: involving configuration of automatic repeat request [ARQ] with parallel processes - H04L 1/1835: {Buffer management} - H04L 1/1874: {Buffer management} - H04W 28/065: {using assembly or disassembly of packets} - H04W 72/1268: of uplink data flows - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 74/02: Hybrid access - H04W 74/0833: Random access procedures, e.g. with 4-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) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Apparatuses, methods, and systems are disclosed for using a medium access control protocol data unit in a message 3 buffer. One method includes, in response to a medium access control protocol data unit being in a message 3 buffer and receiving an uplink grant: obtaining the medium access control protocol data unit from the message 3 buffer; if a first size of the uplink grant does not match a second size of the medium access control protocol data unit: indicating to a multiplexing and assembly entity to include medium access control sub-protocol data units carrying medium access control service data units from the obtained medium access control protocol data unit in a subsequent uplink transmission; and obtaining the medium access control protocol data unit from the multiplexing and assembly entity. ## Claims ### Claim 1 A method comprising: in response to a medium access control protocol data unit being in a message 3 buffer and receiving an uplink grant within a random access response as part of a random access procedure: obtaining the medium access control protocol data unit from the message 3 buffer; if a first size of the uplink grant does not match a second size of the medium access control protocol data unit and if the random access procedure is successfully completed upon receiving the uplink grant: indicating to a multiplexing and assembly entity to include only medium access control sub-protocol data units carrying medium access control service data units from the obtained medium access control protocol data unit in a subsequent uplink transmission; and obtaining the medium access control protocol data unit from the multiplexing and assembly entity. ### Claim 2 (depends on 1) The method of claim 1, wherein receiving the uplink grant comprises receiving the uplink grant within a random access response as part of a contention-free random access procedure. ### Claim 3 (depends on 1) The method of claim 1, further comprising performing a logical channel prioritization procedure based on the uplink grant. ### Claim 4 (depends on 3) The method of claim 3, wherein the medium access control sub-protocol data units are used as inputs to the logical channel prioritization procedure. ### Claim 5 (depends on 3) The method of claim 3, wherein the medium access control sub-protocol data units comprising a medium access control element are excluded from being part of the inputs. ### Claim 6 (depends on 3) The method of claim 3, wherein the medium access control sub-protocol data units comprising padding are excluded from being part of the inputs. ### Claim 7 (depends on 1) The method of claim 1, further comprising instructing the multiplexing and assembly entity to generate medium access control elements contained in the medium access control protocol data unit. ### Claim 8 (depends on 1) The method of claim 1, further comprising flushing a hybrid automatic repeat request buffer used for transmission of the medium access control protocol data unit in the message 3 buffer if a random access channel preamble from a set of contention-based random access preambles is used. ### Claim 9 (depends on 1) The method of claim 1, further comprising flushing a hybrid automatic repeat request buffer used for transmission of the medium access control protocol data unit in the message 3 buffer before processing the uplink grant. ### Claim 10 An apparatus comprising: a receiver; and a processor that: in response to a medium access control protocol data unit being in a message 3 buffer and the receiver receiving an uplink grant within a random access response as part of a random access procedure: obtains the medium access control protocol data unit from the message 3 buffer; if a first size of the uplink grant does not match a second size of the medium access control protocol data unit and if the random access procedure is successfully completed upon receiving the uplink grant: indicates to a multiplexing and assembly entity to include only medium access control sub-protocol data units carrying medium access control service data units from the obtained medium access control protocol data unit in a subsequent uplink transmission; and obtains the medium access control protocol data unit from the multiplexing and assembly entity. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the receiver receiving the uplink grant comprises the receiver receiving the uplink grant within a random access response as part of a contention-free based random access procedure. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein the processor performs a logical channel prioritization procedure based on the uplink grant. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the medium access control sub-protocol data units are used as inputs to the logical channel prioritization procedure. ### Claim 14 (depends on 12) The apparatus of claim 12, wherein the medium access control sub-protocol data units comprising a medium access control element are excluded from being part of the inputs. ### Claim 15 (depends on 12) The apparatus of claim 12, wherein the medium access control sub-protocol data units comprising padding are excluded from being part of the inputs. ### Claim 16 (depends on 10) The apparatus of claim 10, wherein the processor instructs the multiplexing and assembly entity to generate medium access control elements contained in the medium access control protocol data unit. ### Claim 17 (depends on 10) The apparatus of claim 10, wherein the processor flushes a hybrid automatic repeat request buffer used for transmission of the medium access control protocol data unit in the message 3 buffer if a random access channel preamble from a set of contention-based random access preambles is used. ### Claim 18 (depends on 10) The apparatus of claim 10, wherein the processor flushes a hybrid automatic repeat request buffer used for transmission of the medium access control protocol data unit in the message 3 buffer before processing the uplink grant.