Aspects of the present disclosure provide techniques and apparatus for performing narrowband physical random access channel (PRACH) procedures in large cells. For example, aspects of the present disclosure provide techniques for narrowband PRACH procedures (e.g., narrowband internet of things (NB-IoT)) to accommodate larger RTTs (e.g., up to 100 km). In some cases, supporting larger RTTs may involve a base station altering its PRACH processing by performing a two-step process of, first, obtaining a frequency domain phase offset based on an uplink signal from a UE, which provides a fractional delay and, second, performing a time domain correlation for different timing hypotheses to determine a timing offset based on the uplink signal. Supporting larger RTTs may also involve enabling a new NPRACH format that may coexist with legacy 3.75 kHz resources.

A method for wireless communication of a user equipment (UE) in a radio resource control (RRC) Inactive state, the method includes sending, by the UE, an RRC Connection Resume Request message to a base station, and transmitting, by the UE, a packet to the base station using one or more radio resources allocated by the base station, where the base station identifies the UE based on the RRC Connection Resume Request message, which includes a UE ID or a UE-specific preamble. Before the UE enters the RRC Inactive state, the base station sends a pre-configured random access configuration to the UE for transmitting the packet in a subsequent a random access procedure. The pre-configured random access configuration includes at least one of a pre-configured bandwidth part configuration, a plurality of access control parameters, the UE ID, and a time pattern for the random access procedure.

In response to receiving a random access channel message from a User Equipment (UE), a network element in a communication network may initiate a random access procedure, for example. The random access channel message includes multiple sequences, such as a first sequence associated with a group of UEs that includes the UE and a second sequence associated with the UE, and may be in any one of multiple different message formats. The random access procedure could include respective search stages for each of the multiple sequences. Power control for random access message transmission is also implemented by the UE in some embodiments.

Techniques are described for wireless communication. A method for wireless communication at a user equipment (UE) includes receiving an indication of at least one receive capability of a network access device; transmitting a first message of a random access channel (RACH) procedure; receiving a random access response (RAR) message in response to transmitting the first message; and interpreting the RAR message according to a format based at least in part on the received indication. A method for wireless communication at a network access device includes transmitting an indication of at least one receive capability of the network access device; receiving, from a UE, a first message of a RACH procedure; and transmitting a RAR message to the UE in response to receiving the first message. The RAR message has a format based at least in part on the at least one receive capability of the network access device.

Techniques are described herein to improve a link budget of physical random access channel (PRACH) transmissions used during a random access (RACH) procedure. The link budget of a PRACH transmission associated with the RACH procedure may be improved by transmitting multiple PRACH transmissions. The multiple PRACH transmissions may be combined to achieve some combining gain. Each retransmission of a PRACH transmission may be done at a higher power level than the previous PRACH transmission. If UE receives an indication that a target base station failed to successfully decode the PRACH transmission, the UE may retransmit the PRACH transmission but at a higher power level than the initial PRACH transmission. PRACH transmissions may be distributed across multiple slots. PRACH transmissions may be distributed across multiple frequency sub-bands in the same slot or across frequency sub-bands in the different slots.

The present disclosure describes a method, an apparatus, and a computer-readable medium for a random access channel (RACH) procedure at a user equipment. For example, the method may select a two-step RACH procedure or a four-step RACH procedure at the UE based at least on RACH configuration information received from a base station or the RACH configuration information at the UE. The example method may further include transmitting, from the UE, one or more messages associated with the two-step RACH procedure or the four-step RACH procedure based on the selection.

Certain aspects of the present disclosure are generally directed to design of random access channel (RACH) procedures. For example, certain aspects of the present disclosure provide a method for wireless communication by a user equipment (UE). The method generally includes receiving an indication of a RACH procedure capability of a network entity, and selecting a first RACH procedure or a second RACH procedure, based on the indication. The UE may then communicate one or more messages with the network entity based on the selected first RACH procedure or the selected second RACH procedure.

A base station receives from a wireless device repetitions of a random access preamble across a plurality of system frames. The base station further transmits a downlink control information (DCI). The transmitted DCI comprises a system frame number field indicating a system frame number and a radio resource assignment. The base station also transmits a random access response via the radio resource assignment. The base station further determines, in response to the system frame number indicating a last system frame, among the plurality of system frames, on which the base station receives the repetitions, that the random access response corresponds to the random access preamble of the wireless device.

A device identification apparatus, applicable to a first network device, the device identification apparatus includes: a receiver configured to receive first information transmitted by a first device, wherein, the first information is used to indicate that the first device is a Network-Controlled repeater or is used to determine that the first device connects to a network as a Network-Controlled repeater, or, the first information is repeater-specific first information.

A device identification apparatus, applicable to a first network device, the device identification apparatus includes: a receiver configured to receive first information transmitted by a first device, wherein, the first information is used to indicate that the first device is a Network-Controlled repeater or is used to determine that the first device connects to a network as a Network-Controlled repeater, or, the first information is repeater-specific first information.