A wireless device selects, in response to initiating a random access procedure, a first radio resource for transmitting a message. In response to determining the first radio resource is invalid for transmission of the message, the wireless device transmits, via a second radio resource, the message based on determining the second radio resource is valid for the transmission of the message and determining a time difference between the second radio resource and the first radio resource is smaller than a threshold.

Methods, systems, and devices for wireless communications are described. The described techniques may enhance coverage by supporting repetitions of a random access request. A user equipment (UE) may receive, from a network entity, a synchronization signal block (SSB) message. The UE may measure the SSB message in order to determine signal metric, such as reference signal received power (RSRP). Based on the RSRP of the SSB, the UE may determine to transmit a set of repetitions of a random access request. The UE may then monitor a resource of a downlink control channel for a random access response from the network entity.

In response to initiating a two-step random access (RA) procedure, a wireless device selects a first radio resource for transmission of a first message of the two-step RA procedure. Based on the first radio resource being invalid for the transmission of the first message, the wireless device switches from the two-step RA procedure to a four-step RA procedure and transmits, via a second radio resource, a preamble for the four-step RA procedure.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may transmit, and a user equipment (UE) may receive, initial timing advance information in a msg2 communication of a four-step random access channel procedure based at least in part on a subcarrier spacing in a cell associated with the base station. The UE may transmit, and the base station may receive, a msg3 communication with an initial timing advance that is based at least in part on the initial timing advance information. The base station may transmit, and the UE may receive, updated timing advance information resolving a timing advance wrap-around between the UE and the base station based at least in part on the base station detecting the msg3 communication. Numerous other aspects are provided.

Methods, systems, and devices for wireless communications are described. Generally, the described techniques provide for dynamically activating and deactivating random-access channel (RACH) occasions (ROs). A base station may configure one or more ROs on which a user equipment (UE) can transmit RACH messages. If higher priority signaling (e.g., downlink signaling or uplink signaling) overlaps in time with the ROs, the base station may deactivate one or more ROs to decrease the likelihood of self-interference or cross-link interference (e.g., if the UE or the base station are operating in full duplex mode). The base station may deactivate or activate ROs by indicating indices for one or more ROs, indices for one or more synchronization signal blocks (SSBs), a pattern of ROs, some or all ROs within a time period, some or all ROs until a next downlink signal updates the RO configuration or activates ROs, or any combination thereof.

Apparatuses, methods, and systems are disclosed for selecting a base unit in response to a handover condition being triggered. One method (1000) includes selecting (1002) a base unit of multiple base units for handover in response to at least one base unit of the multiple base units triggering a handover condition. The method (1000) includes transmitting (1004) a random access preamble to the base unit. The method (1000) includes performing (1006) a reestablishment procedure to establish communication with one base unit of the multiple base units in response to determining an inability to access each base unit of the multiple base units that meets the handover condition.

A method and an apparatus for maintenance of a bandwidth part. The method and apparatus resolve an issue of the prior art in which expiration of a bandwidth part deactivation timer during a random access process changes the bandwidth part to a default bandwidth part, such that data cannot be transmitted on an optimal bandwidth part, and may even cause an interruption of an ongoing data transmission, while also affecting an ongoing random access process. In embodiments of the present invention, a terminal keeps a current active bandwidth part unchanged during a random access process, and performs a restart operation of a bandwidth part deactivation timer after the random access process is successfully completed, such that a situation where a bandwidth part changes to a default bandwidth part does not occur during the random access process, thereby reducing interruption to ongoing data transmissions and reducing the impact on ongoing random access processes.

To avoid blocking node AC queues in the degraded MU EDCA mode due to regular OFDMA transmission of data from another AC queue in resource units provided by an AP, the present invention proposes to use a dedicated HEMUEDCATimer for each AC queue, in order for them to be able to exit the degraded MU EDCA mode independently of the other AC queues. In this respect, upon successfully transmitting data stored in two or more traffic queues, in each of one or more accessed resource units provided by the AP within one or more transmission opportunities, the node sets each traffic queue transmitting in the accessed resource unit in the degraded MU EDCA mode for a predetermined degrading duration counted down by a respective timer associated with the transmitting traffic queue. Next, upon expiry of any timer, the node switches back the associated traffic queue to the conventional EDCA mode.

Methods, systems, and devices for wireless communication are described. A base station may determine a configuration including a set of signature waveforms for a micro-sleep mode of operation in shared spectrum, and may transmit the configuration to at least one user equipment (UE) served by the base station. Additionally, a UE may receive a configuration including a set of signature waveforms for a micro-sleep mode of operation in shared spectrum. The UE may detect at least one signature waveform of the set of signature waveforms, and in response to detecting the at least one signature waveform, operate in the micro-sleep mode for a period of time.

A system for converging fifth generation (5G) communication systems for supporting higher data rates beyond fourth generation (4G) systems with a technology for Internet of things (IoT) is provided. The communication method and system may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A system is provided for determining system information validity by acquiring and storing a first system information block and other system information, including information on a public land mobile network (PLMN) identity and a value tag, and determining whether the stored system information is valid for the cell. As another example, a terminal and base station are provided for performing beam failure detection and a recovery procedure using first and second configuration information for beam failure recovery (BFR) and if failure is detected, initiating a first random access (RA) procedure and if second configuration information is received while the first RA procedure is ongoing, terminating the first RA procedure and initiating a second RA procedure based on the second configuration information.