Disclosed is the radio (wireless) communication system providing a radio communication service and the terminal, and more particularly, to a method of an uplink HARQ (Hybrid Automatic Repeat reQuest) operation at an expiry of time alignment timer in an Evolved Universal Mobile Telecommunications System (E-UMTS) evolved from the Universal Mobile Telecommunications System (UMTS) or a Long Term Evolution (LTE) system.

Techniques and apparatus for hybrid automatic retransmission request (HARQ) acknowledgement (ACK) bundling in half duplex frequency division duplexing (HD-FDD) systems are provided. One technique includes determining ACK parameter(s) to be used for acknowledging a bundled transmission that includes instance(s) of a channel across subframe(s). An indication of the ACK parameter(s) is signaled to a user equipment (UE). The ACK parameter(s) include a first ACK parameter that conveys a size of the bundled transmission and a second ACK parameter that conveys an amount of time for the UE to delay acknowledging a data transmission in an instance of the channel after receiving the data transmission. The UE may acknowledge the bundled transmission in accordance with the ACK parameter(s).

Methods and apparatuses are provided for generating a protocol data unit (PDU). An apparatus may comprise a processor configured to provide a medium access control (MAC) entity and a segmentation entity. The MAC entity may indicate an amount of data associated with the segmentation entity to be multiplexed by the MAC entity. The segmentation entity may segment, based on the indicated amount of data, a service data unit (SDU) into a segment, and the MAC entity may multiplex the segment into a MAC protocol data unit (PDU). The MAC PDU may include a field that indicates whether the segment is included and whether the segment is a last segment. The apparatus may further comprise a transmitter configured to transmit the MAC PDU.

Timing considerations for autonomous uplink (AUL) downlink feedback information (AUL-DFI) is disclosed. With the flexible timeline for new radio (NR) operations, signaling of the processing timeline may be used for the served user equipments (UEs) to properly interpret the acknowledgement information in the AUL-DFI. The UE receives a signal identifying a minimum processing time of the serving base station to process AUL. Using the knowledge of the minimum processing time, the UE determines which of the outstanding AUL transmissions are accurately addressed in the AUL-DFI and which are still pending. Additional signaling to the UE may instruct the UE when to implement any changes to transmission parameters also signaled via the AUL-DFI. Slots prior to the indicated change time will be transmitted using the current parameters, while slots after the indicated time will use the updated parameters from the AUL-DFI.

An operation method of a receiving terminal in sidelink communications may comprise: receiving one or more transport blocks (TBs) from a transmitting terminal; generating hybrid automatic repeat request (HARQ) responses for code block groups (CBGs) included in each of the one or more TBs; selecting one or more HARQ responses from among the HARQ responses based on priorities; and transmitting the one or more HARQ responses to the transmitting terminal through a physical sidelink feedback channel (PSFCH) resource.

A method and apparatus for sending uplink control information by a multi-mode wireless transmit/receive unit (WTRU) capable of operating on multiple component carriers of a plurality of radio access technologies (RATs) for multi-RAT operation are disclosed. The WTRU may generate uplink control information (UCI) pertaining to a first RAT and a second RAT, wherein the UCI may include a first plurality of hybrid automatic repeat request acknowledgements (HARQ-ACKs) pertaining to a plurality of downlink (DL) transmissions of the first RAT and a second plurality of HARQ-ACKs pertaining to a plurality of DL transmissions of the second RAT. The WTRU may multiplex at least part of the generated UCI pertaining to the first RAT and at least part of the generated UCI pertaining to the second RAT onto a physical channel on a component carrier of the second RAT.

Certain aspects of the present disclosure provide techniques and apparatus for hybrid automatic repeat request (HARQ) feedback retransmission. An example method of wireless communication by a user equipment generally includes receiving signaling indicating to reschedule HARQ feedback for transmission; determining the HARQ feedback based at least in part on one or more fields of the signaling; and transmitting the HARQ feedback based on the determination.

A user equipment is configured with at least two collections of uplink resources to be used for transmitting control information to a communication network. The UE receives an assignment of radio resources to be used for receiving a downlink transmission from a base station of the communication network. The UE receives an acknowledgement resource indication, ARI, indicating one of the configured collections of uplink resources to be used for transmitting control information associated with the DL transmission. Further, the UE transmits the control information to the base station on at least a subset of the indicated collection of UL resources. In example embodiments, the indicated collection of uplink resources comprises a plurality of selectable uplink resource sets. The control information is transmitted on one of the uplink resource sets which corresponds to an operational state of the communication network.

Disclosed is a wireless communication base station apparatus whereby it is possible to prevent degradation of throughput of LTE terminals, even when LTE terminals and LTE+ terminals are present together. In this apparatus, a setting section (105) sets in each subframe a resource block in which is arranged a reference signal that is employed solely by LTE+ terminals, based on the pattern of arrangement of reference signals employed solely by LTE+ terminals. In the case of symbols that are mapped to antennas (110-1) to (110-4), an arrangement section (106) arranges the characteristic cell reference signals employed by both LTE terminals and LTE+ terminals in all of the resource blocks in a single frame. In contrast, in the case of the symbols that are mapped to the antennas (110-5) to (110-8), the arrangement section (106) arranges in some of the resource blocks, that are set in accordance with the setting results input from a setting section (105), the characteristic cell reference signals that are employed solely by the LTE+ terminals.

The present disclosure provides a random access method and a terminal device. The method includes: reserving a first MAC PDU buffered in a HARQ buffer or buffering a second MAC PDU in a HARQ buffer if a random access procedure is successful, where the first MAC PDU is a PDU that is buffered in a Msg3 buffer in a contention random access procedure, the second MAC PDU is a PDU that includes at least data content of the first MAC PDU and is buffered in a target buffer, and the target buffer and the Msg3 buffer are different buffers.