Repeated random access transmission

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may send a first random access channel (RACH) message multiple times on a corresponding RACH opportunity until a second RACH message is received from a base station in a random access response (RAR) window. Sending the first RACH message multiple times may include: a preamble sequence selected from a subset of preamble sequences configured for such a repeated first RACH message transmission scheme. In addition, the UE subset may use such a repeated first RACH message transmission scheme based on a link condition between the UE and the base station, an exposure condition of the UE, other measurements, and the like. In some cases, a shortened RAR window length may be configured for such a repeated first RACH message transmission scheme.

Description

[0001] Cross-references

[0002] This patent application claims the benefits of the following applications: U.S. Provisional Patent Application No. 63 / 013,136, entitled “Repetitive Random Access Transmissions,” filed by Taherzadeh Boroujeni et al. on April 21, 2021, and U.S. Patent Application No. 17 / 223,383, entitled “Repetitive Random Access Transmissions,” filed by Taherzadeh Boroujeni et al. on April 6, 2021, each of which is assigned to the assignee of this application. Technical Field

[0003] The following relates generally to wireless communications, and more particularly, to repeated random access transmissions. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems (e.g., long term evolution (LTE) systems, improved LTE (LTE-A) systems, or LTE-A Pro systems) and fifth generation (5G) systems (which may be referred to as new radio (NR) systems). These systems may employ techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiplexing (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM).

[0005] A wireless multiple access communication system may include multiple base stations or network access nodes, each of which simultaneously supports communications for multiple communication devices, which may be further referred to as user equipment (UE). When connecting to a base station to receive or send subsequent communications, the UE may perform a random access channel (RACH) procedure to establish a connection with the base station. Summary of the invention

[0006] The described technology relates to improved methods, systems, devices and apparatuses for supporting repeated random access transmissions. In general, the described technology provides that a user equipment (UE) sends a random access request message for a random access channel (RACH) process during two or more occasions based on received configuration information for the RACH process (e.g., received from a base station or other network device). For example, the UE may send a first instance of the random access request message during a first opportunity, a second instance of the random access request message during a second opportunity, and so on. In addition, the UE may use a subset of RACH preambles from a full set of RACH preambles that can be used for the RACH process when sending the random access request message during two or more opportunities, wherein the subset of RACH preambles is indicated in the configuration information for the RACH process. In some cases, the UE may determine to send the random access request message during two or more opportunities based on a power measurement satisfying a threshold, an exposure condition of the UE, an additional measurement, or a combination thereof. In addition, the UE may determine the number of opportunities for sending the random access request message based on the configuration information for the RACH process.

[0007] In some cases, the configuration information for the RACH procedure may also include two or more time lengths for a random access response (RAR) window (e.g., a time window), wherein the RAR window is used to transmit a RAR of the RACH procedure to the UE (e.g., in response to a random access request message). For example, the base station may receive two or more instances of the random access request message during two or more corresponding occasions, and may then determine to send the RAR to the UE during the RAR window based on the configuration information. Based on sending the random access request message during two or more occasions, the UE and the base station may use a shortened length RAR window compared to a longer RAR window length for a RACH procedure in which the UE sends the random access request message once. Therefore, using the shortened length RAR window, the UE may send each instance of the random access request message during an opportunity that occurs after the shortened length RAR window expires. For example, the UE may send a first instance of the random access request message during a first opportunity, wait for a duration equal to the shortened length of the RAR window, then send a second instance of the random access request message during a second opportunity, wait again for a duration equal to the shortened length of the RAR window, and so on, until sending a last instance of the random access request message during a last opportunity, and then the UE monitors the RAR during subsequent RAR windows with shortened lengths.

[0008] A method of wireless communication at a UE is described. The method may include: receiving configuration information from a base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information; determining, based on a condition of a communication link between the UE and the base station, to send a random access request message of the random access procedure during two or more opportunities in the set of opportunities; and sending a first instance of the random access request message during a first opportunity in the set of opportunities and sending a second instance of the random access request message during a second opportunity in the set of opportunities based on the determination to send the random access request message during two or more opportunities in the set of opportunities.

[0009] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to perform the following operations: receive configuration information from a base station for performing a random access procedure with the base station within a timing set associated with the configuration information; determine, based on a condition of a communication link between the UE and the base station, to send a random access request message for the random access procedure during two or more timings in the timing set; and send a first instance of the random access request message during a first timing in the timing set and send a second instance of the random access request message during a second timing in the timing set based on determining to send the random access request message during two or more timings in the timing set.

[0010] Another apparatus for wireless communication at a UE is described. The apparatus may include: a unit for receiving configuration information from a base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information; a unit for determining, based on a condition of a communication link between the UE and the base station, to send a random access request message for the random access procedure during two or more opportunities in the set of opportunities; and a unit for sending a first instance of the random access request message during a first opportunity in the set of opportunities and sending a second instance of the random access request message during a second opportunity in the set of opportunities based on determining to send the random access request message during two or more opportunities in the set of opportunities.

[0011] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to: receive configuration information from a base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information; determine, based on a condition of a communication link between the UE and the base station, to send a random access request message of the random access procedure during two or more opportunities in the set of opportunities; and send a first instance of the random access request message during a first opportunity in the set of opportunities and send a second instance of the random access request message during a second opportunity in the set of opportunities based on the determination to send the random access request message during two or more opportunities in the set of opportunities.

[0012] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving information from a base station indicating a subset of random access preambles associated with sending a random access request message within two or more occasions in a set of occasions, the random access preamble subset being indicated from a set of random access preambles that can be used for a random access procedure, wherein determining to send the random access request message during the two or more occasions is based on the received information.

[0013] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: selecting a random access preamble from a subset of random access preambles, wherein the first instance and the second instance of sending a random access request message during the first opportunity and the second opportunity include sending the random access preamble.

[0014] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a different cyclic shift may be applied to the random access preamble for each instance of sending a random access request message.

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: selecting a first random access preamble for a first occasion from a subset of random access preambles, wherein sending a first instance of a random access request message during the first occasion includes sending the first random access preamble; and selecting a second random access preamble for a second occasion from the subset of random access preambles, wherein sending a second instance of a random access request message during the second occasion includes sending the second random access preamble.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: using configuration information to perform power measurements associated with a communication link; and determining that the power measurement satisfies a threshold, wherein determining to send a random access request message during two or more occasions is based on the power measurement satisfying the threshold.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the power measurement may include a reference signal received power (RSRP) measurement, a received signal strength indication (RSSI) measurement, or a combination thereof.

[0018] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for identifying an exposure condition of the UE, wherein determining to send a random access request message during two or more opportunities is based on the exposure condition of the UE.

[0019] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving from a base station information indicating a first length of a time window associated with sending a random access request message within two or more occasions in a timing set, and a second length of a time window associated with sending a random access request message at a single occasion in the timing set, the time window being used to transmit a RAR of a random access procedure to a UE, and the first length being shorter than the second length.

[0020] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a first instance of a random access request message may be sent before a first time window having a first length, and a second instance of the random access request message may be sent after a first time window associated with the first instance expires according to the first length.

[0021] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for monitoring a RAR of a random access procedure after a last instance of sending a random access request message, wherein the RAR is monitored during a time window according to a first length.

[0022] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining a first length of a time window and a second length of a time window based on a single bit field in the information, a time window length table, or a combination thereof.

[0023] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first length of the time window can be based on the second length of the time window, the frequency range used for the random access procedure, the frequency band used for the random access procedure, or a combination thereof.

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining a number of opportunities for sending a random access request message in a set of opportunities based on configuration information, wherein determining to send a random access request message during two or more opportunities is based on determining the number of opportunities.

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the number of opportunities to send a random access request message can be based on a bandwidth used to perform a random access procedure, a frequency range used for the random access procedure, a spectrum band used for the random access procedure, or a combination thereof.

[0026] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the configuration information may be received via a synchronization signal block (SSB), a system information block (SIB), system information, or a combination thereof.

[0027] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, an opportunity set may occur between receiving a first SSB carrying configuration information and receiving a second SSB carrying additional configuration information.

[0028] A method of wireless communication at a base station is described. The method may include: sending configuration information to a UE for the UE to perform a random access procedure with the base station within a set of opportunities associated with the configuration information; receiving a first instance of a random access request message for the random access procedure from the UE during a first opportunity in the set of opportunities; receiving a second instance of the random access request message for the random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity; and sending a RAR for the random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving the first instance and the second instance of the random access request message during two or more opportunities in the set of opportunities.

[0029] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to perform the following operations: send configuration information to a UE for the UE to perform a random access procedure with the base station within a timing set associated with the configuration information; receive a first instance of a random access request message for the random access procedure from the UE during a first timing in the timing set; receive a second instance of a random access request message for the random access procedure from the UE during a second timing in the timing set, the second timing occurring after the first timing; and send a RAR for the random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving the first instance and the second instance of the random access request message during two or more timings in the timing set.

[0030] Another apparatus for wireless communication at a base station is described. The apparatus may include: a unit for sending configuration information to a UE for the UE to perform a random access procedure with the base station within a set of opportunities associated with the configuration information; a unit for receiving a first instance of a random access request message for the random access procedure from the UE during a first opportunity in the set of opportunities; a unit for receiving a second instance of the random access request message for the random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity; and a unit for sending a RAR for the random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving the first instance and the second instance of the random access request message during two or more opportunities in the set of opportunities.

[0031] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to: send configuration information to a UE for the UE to perform a random access procedure with the base station within a set of opportunities associated with the configuration information; receive a first instance of a random access request message for the random access procedure from the UE during a first opportunity in the set of opportunities; receive a second instance of the random access request message for the random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity; and send a RAR for the random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving the first instance and the second instance of the random access request message during two or more opportunities in the set of opportunities.

[0032] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for sending to a UE information indicating a random access preamble subset associated with the UE sending a random access request message within two or more occasions in a set of occasions, the random access preamble subset being indicated from a set of random access preambles that can be used for a random access procedure.

[0033] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first instance and the second instance of the random access request message may be received with the same random access preamble or different random access preambles.

[0034] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a first instance of a random access request message may be received with a random access preamble having a first cyclic shift applied, and a second instance of the random access request message may be received with a random access preamble having a second cyclic shift applied.

[0035] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: sending to a UE information indicating a first length of a time window associated with the UE sending a random access request message within two or more occasions in a timing set, and a second length of a time window associated with the UE sending a random access request message at a single occasion in the timing set, the first length being shorter than the second length.

[0036] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining a first length of the time window based on a second length of the time window, a frequency range used for a random access procedure, a frequency band used for a random access procedure, or a combination thereof.

[0037] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first length of the time window and the second length of the time window may be indicated based on a single bit field in signaling, a time window length table, or a combination thereof.

[0038] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the second instance of the random access request message may be received after the first instance of the random access request message according to the first length.

[0039] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a number of opportunities for the UE to send a random access request message, wherein the number of opportunities is based on a bandwidth for performing a random access procedure, a frequency range for the random access procedure, a frequency band for the random access procedure, or a combination thereof; and sending an indication of the number of opportunities to the UE in configuration information.

[0040] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining that the UE will send a random access request message within two or more occasions in a timing set, wherein a first instance and a second instance of the random access request message may be received based on determining that the UE will send a random access request message within two or more occasions in the timing set.

[0041] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, determining that the UE will send a random access request message within two or more opportunities in a set of opportunities can be based on power measurements, exposure conditions of the UE, or a combination thereof.

[0042] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: selecting a first beam to receive a first instance of a random access request message; and selecting a second beam to receive a second instance of the random access request message, the second beam being different from the first beam.

[0043] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first beam and the second beam may be different based on a beam refinement process.

[0044] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the configuration information may be sent via SSB, SIB, system information, or a combination thereof.

[0045] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, opportunity set may occur between sending a first SSB carrying configuration information and sending a second SSB carrying additional configuration information. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 An example of a system for wireless communications supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown.

[0047] Figure 2An example of a wireless communication system supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown.

[0048] Figure 3 Examples of repeated random access transmission configurations in accordance with aspects of the present disclosure are shown.

[0049] Figure 4 An example of a process flow supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown.

[0050] Figure 5 and Figure 6 A block diagram illustrating an apparatus supporting repeated random access transmissions in accordance with aspects of the present disclosure.

[0051] Figure 7 A block diagram of a user equipment communication manager supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown.

[0052] Figure 8 A diagram illustrating a system including a device supporting repeated random access transmissions in accordance with aspects of the present disclosure.

[0053] Fig. 9 and Fig.10 A block diagram illustrating an apparatus supporting repeated random access transmissions in accordance with aspects of the present disclosure.

[0054] Fig.11 A block diagram of a base station communications manager supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown.

[0055] Fig.12 A diagram illustrating a system including a device supporting repeated random access transmissions in accordance with aspects of the present disclosure.

[0056] Figures 13 to 19 A flow chart illustrating a method of supporting repeated random access transmissions according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0057] When establishing a connection between a base station and a user equipment (UE), the UE and the base station may perform a random access channel (RACH) procedure to obtain information for the connection. In some cases, the RACH procedure may involve a two-step RACH procedure or a four-step RACH procedure. In a two-step RACH procedure, two (2) messages are exchanged between the UE and the base station. In a four-step RACH procedure, four (4) messages are exchanged between the UE and the base station. In both types of RACH procedures, the UE may send a first RACH message to request the start of the RACH procedure. The first message may be referred to as a RACH request message, a random access request message, a RACH preamble, a physical RACH (PRACH) preamble, msg1, msgA, etc. However, when communication is established between the UE and the base station based on the base station not successfully receiving the first RACH message, the UE using inefficient transmission parameters to send the first RACH message, or a combination thereof, the first message of the RACH procedure may provide a bottleneck.

[0058] Described herein are systems, devices, and techniques in which a UE can use the same preamble sequence or linked preamble sequence to send a first RACH message multiple times on corresponding RACH occasions to improve the reliability of the first RACH message being successfully received at a base station. In some cases, the first RACH message can be sent until a second RACH message is received from a base station in a random access response (RAR) window (e.g., after the last opportunity to send the first RACH message). Sending the first RACH message multiple times may include: a preamble sequence selected from a subset of preamble sequences configured for such repeated transmission of the first RACH message. For example, by using a subset of preamble sequences associated with repeated transmissions of the first RACH message, the base station can more easily detect, receive, and decode the first RACH message that is transmitted multiple times. In addition, a subset of UEs can use such a repeated first RACH message transmission scheme based on the link condition between the UE and the base station. Examples of link conditions may include power measurements, exposure conditions of the UE, other measurements, and the like.

[0059] In some cases, a shortened RAR window length may be used when sending a first RACH message using such a repeated first RACH message transmission scheme, compared to a RAR window length for a RACH process that does not use repeated RACH transmissions. In addition, such a repeated first RACH message transmission scheme may be used for a number of opportunities (e.g., quantity) between receiving a first synchronization signal block (SSB) (e.g., a synchronization signal (SS) / physical broadcast channel (PBCH) block) (which configures a repeated first RACH message transmission scheme) and receiving a second SSB (which configures a different RACH process). In some cases, the number of opportunities to send the first RACH message may be configured by the base station.

[0060] Various aspects of the present disclosure are first described in the context of wireless communication systems. In addition, various aspects of the present disclosure are illustrated by additional wireless communication systems, repeated random access transmission configurations, and process flows. Various aspects of the present disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flow charts related to repeated random access transmissions.

[0061] Figure 1 An example of a wireless communication system 100 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an improved LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

[0062] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support transmission of signals according to one or more radio access technologies.

[0063] UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, mobile, or both at different times. UEs 115 may be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. 1 . The UEs 115 described herein are capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices). Figure 1 as shown in .

[0064] The base stations 105 may communicate with the core network 130, or with each other, or both. For example, the base stations 105 may interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105), or indirectly (e.g., via the core network 130), or both via the backhaul links 120 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul links 120 may be or include one or more wireless links.

[0065] One or more of the base stations 105 described herein may include or be referred to by a person of ordinary skill in the art as a base station transceiver, a radio base station, an access point, a radio transceiver, a Node B, an eNodeB (eNB), a next generation Node B or a giga Node B (any of which may be referred to as a gNB), a Home Node B, a Home eNodeB or other appropriate terminology.

[0066] UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device or a subscriber device, or some other appropriate terminology, where a "device" may also be referred to as a unit, a station, a terminal or a client, etc. UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or may be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be implemented in various items such as home appliances, or vehicles, meters, etc.

[0067] The UE 115 described herein is capable of communicating with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as base stations 105 and network devices, including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, such as Figure 1 as shown in .

[0068] The UE 115 and the base station 105 can communicate with each other wirelessly via one or more communication links 125 on one or more carriers. The term "carrier" can refer to a set of radio frequency spectrum resources with a specified physical layer structure to support the communication link 125. For example, the carrier used for the communication link 125 may include a portion of the radio frequency spectrum band (e.g., bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel can carry acquisition signaling (e.g., synchronization signals, system information), control signaling to coordinate operations for the carrier, user data, or other signaling. The wireless communication system 100 can use carrier aggregation or multi-carrier operation to support communication with the UE 115. According to the carrier aggregation configuration, the UE 115 can be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used with frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0069] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling for coordinating operations with respect to other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel raster for discovery by UE 115. A carrier may operate in a standalone mode, where initial acquisition and connection may be performed by UE 115 via the carrier, or a carrier may operate in a non-standalone mode, where the connection is anchored using a different carrier (e.g., the same or different radio access technology).

[0070] The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry both downlink and uplink communications (e.g., in TDD mode).

[0071] A carrier may be associated with a particular bandwidth of a radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as a "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of a plurality of determined bandwidths of a carrier for a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). A device of the wireless communication system 100 (e.g., a base station 105, a UE 115, or both) may have a hardware configuration that supports communications on a particular carrier bandwidth, or may be configurable to support communications on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communications via carriers associated with a plurality of carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., a subband, a BWP) or all of a carrier bandwidth.

[0072] The signal waveform transmitted through the carrier wave may be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Therefore, the more resource elements received by the UE 115 and the higher the order of the modulation scheme, the higher the data rate of the UE 115. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity used to communicate with the UE 115.

[0073] One or more numerologies for a carrier may be supported, where the numerologies may include subcarrier spacing (Δf) and cyclic prefixes. A carrier may be divided into one or more BWPs with the same or different numerologies. In some examples, a UE 115 may be configured with multiple BWPs. In some examples, a single BWP of a carrier may be active at a given time, and communications for a UE 115 may be limited to the one or more active BWPs.

[0074] The time interval for the base station 105 or the UE 115 may be expressed as a multiple of a basic time unit, for example, the basic time unit may be referred to as T s =1 / (Δf max ·N f ) seconds sampling period, where Δfmax It can represent the maximum supported subcarrier spacing, and N f The maximum supported discrete Fourier transform (DFT) size may be indicated. The time intervals of the communication resources may be organized according to radio frames, each radio frame having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0075] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, the frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into multiple time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include multiple symbol periods (e.g., depending on the length of the cyclic prefix appended to the front of each symbol period). In some wireless communication systems 100, the time slots may be further divided into multiple micro-time slots containing one or more symbols. In addition to the cyclic prefix, each symbol period may contain one or more (e.g., N f ) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or the operating band.

[0076] A subframe, slot, mini-slot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI)).

[0077] Physical channels may be multiplexed on a carrier according to various techniques. For example, physical control channels and physical data channels may be multiplexed on a downlink carrier using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a plurality of symbol periods and may extend across a system bandwidth or a subset of a system bandwidth of a carrier. One or more control regions (e.g., CORESETs) may be configured for a group of UEs 115. For example, one or more UEs in UE 115 may monitor or search a control region to obtain control information according to one or more search space sets, and each search space set may include one or more control channel candidates with one or more aggregation levels arranged in a cascaded manner. The aggregation level for a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0078] Each base station 105 can provide communication coverage via one or more cells (e.g., macro cells, small cells, hot spots or other types of cells or any combination thereof). The term "cell" can refer to a logical communication entity used for communication with the base station 105 (e.g., via a carrier), and can be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), etc.) for distinguishing adjacent cells. In some examples, a cell can also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors (e.g., the capabilities of the base station 105), the range of such a cell can range from a smaller area (e.g., a building, a subset of a building) to a larger area. For example, a cell can be or include a building, a subset of a building, or an external space between or overlapping a geographic coverage area 110, etc.

[0079] A macro cell typically covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by a UE 115 having a service subscription with a network provider that supports the macro cell. A small cell may be associated with a lower power base station 105 than a macro cell, and the small cell may operate in the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. A small cell may provide unrestricted access to a UE 115 having a service subscription with a network provider, or may provide restricted access to a UE 115 associated with the small cell (e.g., a UE 115 in a closed subscriber group (CSG), a UE 115 associated with a user in a home or office). A base station 105 may support one or more cells, and may also support communication on one or more cells using one or more component carriers.

[0080] In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access to different types of devices.

[0081] In some examples, the base stations 105 may be mobile and thus provide communication coverage for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. For example, the wireless communication system 100 may include a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0082] The wireless communication system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and in some examples, transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for either synchronous operation or asynchronous operation.

[0083] Some UEs 115 may be configured to employ an operating mode that reduces power consumption, such as half-duplex communication (e.g., a mode that supports unidirectional communication by sending or receiving but does not support sending and receiving simultaneously). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power saving techniques for UE 115 include entering a power-saving deep sleep mode when not participating in active communications, operating on a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, UE 115 may be configured to operate using a narrowband protocol type, wherein the narrowband protocol type is associated with a specified portion or range (e.g., a subcarrier set or resource block (RB)) within a carrier, within a guard band of a carrier, or outside a carrier.

[0084] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. UE115 can be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication may include private communication or group communication, and may be supported by one or more mission-critical services (e.g., mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData)). Support for mission-critical functions may include prioritizing services, and mission-critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency may be used interchangeably herein.

[0085] In some examples, UE 115 is also able to communicate directly with other UE 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 using D2D communication may be located within a geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be located outside the geographic coverage area 110 of the base station 105, or may otherwise be unable to receive transmissions from the base station 105. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, in which each UE 115 sends a signal to each other UE 115 in the group. In some examples, the base station 105 facilitates the scheduling of resources for use in D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0086] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connection, and other access, routing or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobile management entity (MME), an access and mobility management function (AMF)) for managing access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) for routing packets or interconnections to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UE 115 served by a base station 105 associated with the core network 130. User IP packets may be transmitted through a user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator IP service 150. The operator IP service 150 may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0087] Some of the network devices (e.g., base stations 105) may include subcomponents such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with the UE 115 through one or more other access network transport entities 145 (which may be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs)). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs), or combined in a single network device (e.g., base station 105).

[0088] The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Typically, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, but for macro cells, these waves may penetrate buildings sufficiently to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) than transmission using the lower frequencies and longer wavelengths of the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0089] The wireless communication system 100 can utilize both licensed and unlicensed radio spectrum bands. For example, the wireless communication system 100 can employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band (such as the 5 GHz industrial, scientific, and medical (ISM) band). When operating in an unlicensed radio frequency spectrum band, devices such as base stations 105 and UEs 115 can employ carrier sensing to achieve conflict detection and avoidance. In some examples, operations in unlicensed bands can be based on carrier aggregation configurations combined with component carriers operating in licensed bands (e.g., LAA). Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, etc.

[0090] The base station 105 or UE 115 may be equipped with multiple antennas that may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located within one or more antenna arrays or antenna panels that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be located at the same antenna assembly (e.g., an antenna tower). In some examples, antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array with multiple rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0091] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or control an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array so that certain signals propagating in a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals transmitted via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with a specific orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0092] The base station 105 or the UE 115 may use beam scanning techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. The base station 105 may send some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times in different directions. For example, the base station 105 may send signals based on different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device such as the base station 105 or a receiving device such as the UE 115) a beam direction for the base station 105 to later transmit or receive.

[0093] Base station 105 may transmit some signals (e.g., data signals associated with a particular receiving device) in a single beam direction (e.g., a direction associated with a receiving device such as UE 115). In some examples, the beam direction associated with transmissions along the single beam direction may be determined based on signals transmitted in one or more beam directions. For example, UE 115 may receive one or more of the signals transmitted by base station 105 in different directions and may report to base station 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0094] In some examples, transmissions by a device (e.g., a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from the base station 105 to the UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may send a precoded or unprecoded reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)). The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals sent by base station 105 in one or more directions, UE 115 may employ similar techniques to send signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by UE 115) or to send signals in a single direction (e.g., for sending data to a receiving device).

[0095] When receiving various signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) from the base station 105, the receiving device (e.g., UE 115) can try multiple reception configurations (e.g., directional listening). For example, the receiving device can try multiple reception directions by receiving via different antenna subarrays, processing the received signals according to different antenna subarrays, receiving according to different reception beamforming weight sets (e.g., different directional listening weight sets) applied to the signals received at multiple antenna elements of the antenna array, or processing the received signals according to different reception beamforming weight sets applied to the signals received at multiple antenna elements of the antenna array, any of which can be referred to as "listening" according to different reception configurations or reception directions. In some examples, the receiving device can use a single reception configuration to receive along a single beam direction (e.g., when receiving a data signal). The single reception configuration can be aligned on a beam direction determined based on listening according to different reception configuration directions (e.g., a beam direction determined to have the highest signal strength, the highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

[0096] The wireless communication system 100 can be a packet-based network that operates according to a layered protocol stack. In the user plane, the communication of the bearer or packet data convergence protocol (PDCP) layer can be based on IP. The radio link control (RLC) layer can perform packet segmentation and reorganization to communicate through logical channels. The medium access control (MAC) layer can perform priority processing, as well as multiplexing of logical channels to transport channels. The MAC layer can also use error detection technology, error correction technology, or both to support retransmission of the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection between the UE 115 and the base station 105 or the core network 130 that supports the wireless bearer for user plane data. At the physical layer, the transport channel can be mapped to the physical channel.

[0097] UE 115 and base station 105 can support retransmission of data to increase the likelihood that the data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood that data is correctly received through communication link 125. HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, a device can support HARQ feedback for the same time slot, wherein the device can provide HARQ feedback in a specific time slot for data received in a previous symbol in the time slot. In other cases, the device can provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0098] A UE 115 attempting to access a wireless network may perform an initial cell search by detecting a primary synchronization signal (PSS) from a base station 105. The PSS may implement synchronization of time slot timing and may indicate a physical layer identification value. The UE 115 may then receive a secondary synchronization signal (SSS). The SSS may implement radio frame synchronization and may provide a cell identification value, which may be combined with a physical layer identification value to identify a cell. The SSS may also implement detection of a duplex mode and a cyclic prefix length. Some systems (e.g., TDD systems) may send an SSS but not a PSS. The PSS and SSS may be located in the center 62 and 72 subcarriers of a carrier, respectively. In some cases, the base station 105 may use multiple beams in a beam scanning manner to send synchronization signals (e.g., PSS, SSS, etc.) throughout the cell coverage area. In some cases, PSS, SSS, and / or broadcast information (e.g., PBCH) may be sent in different SS blocks (e.g., SSBs) on corresponding directional beams, wherein one or more SSBs may be included in an SS burst.

[0099] After receiving the PSS and SSS, the UE 115 may receive a master information block (MIB) that may be sent in the PBCH. The MIB may contain system bandwidth information, SFN, and physical HARQ indicator channel (PHICH) configuration. After decoding the MIB, the UE 115 may receive one or more system information blocks (SIBs). For example, the first SIB (SIB1) may contain cell access parameters and scheduling information for other SIBs. Decoding SIB1 may enable the UE 115 to receive a second SIB (SIB2). SIB2 may contain RRC configuration information related to RACH procedures, paging, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), power control, sounding reference signal (SRS), and cell restrictions.

[0100] After completing the initial cell synchronization, the UE 115 may decode the MIB, SIB1, and SIB2 before accessing the network. The MIB may be transmitted on the PBCH and may utilize the first four (4) OFDMA symbols of the second slot of the first subframe of each radio frame. In addition, the MIB may use the middle 6 RBs (72 subcarriers) in the frequency domain. The MIB may carry several important pieces of information for UE initial access, including downlink channel bandwidth (in terms of RBs), PHICH configuration (duration and resource allocation), and SFN. A new MIB may be broadcast every fourth radio frame (SFN mod 4=0) and replayed every frame (10ms). Each repetition is scrambled using a different scrambling code.

[0101] After reading the MIB (new version or copy), the UE 115 can try different phases of the scrambling code until the UE 115 obtains a successful CRC check. The phase of the scrambling code (0, 1, 2, or 3) can enable the UE 115 to identify which of the four repetitions has been received. Therefore, the UE 115 can determine the current SFN by reading the SFN in the decoded transmission and adding the scrambling code phase. After receiving the MIB, the UE 115 can receive one or more SIBs. Different SIBs can be defined according to the type of system information transmitted. A new SIB1 can be transmitted in the fifth subframe of every eighth frame (SFN mod 8=0) and replayed every other frame (20ms). SIB1 may include access information (e.g., initial access related parameters), including cell identification information, and may indicate whether the UE 115 is allowed to camp on the cell. SIB1 may also include cell selection information (or cell selection parameters). In addition, SIB1 may include scheduling information for other SIBs. SIB2 may be dynamically scheduled based on information in SIB1 and may include access information and parameters related to common and shared channels. The periodicity of SIB2 may be set to 8, 16, 32, 64, 128, 256, or 512 radio frames. Based on reading the SSB and SIB1 (e.g., and subsequently SIB2), UE 115 may acquire a cell to potentially establish a connection with the cell (e.g., base station 105).

[0102] After the UE 115 decodes SIB2, the UE 115 may send a RACH preamble (e.g., message 1 (Msgl) in a four-step RACH process) to the base station 105. For example, the RACH preamble may be randomly selected from a set of 64 predetermined sequences. This random selection may enable the base station 105 to distinguish between multiple UEs 115 attempting to access the system simultaneously. The base station 105 may respond with a RAR (e.g., a second message (Msg2)) that provides an uplink resource grant, a timing advance (TA), and a temporary cell radio network temporary identifier (C-RNTI). That is, the base station 105 may detect Msg1 and then send Msg2 by sending both a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH). For example, the PDCCH may be scrambled with a random access radio network temporary identifier (RA-RNTI), which is a function of the RACH timing used by the UE 115 to send Msg1. Within the PDSCH, the base station 105 may include a MAC control element (MAC-CE) to acknowledge receipt of Msg1 and grant an uplink grant to the UE 115 for sending a third message (Msg3) of the RACH procedure. In some cases, the UE 115 may send Msg1 with a power ramp-up so that if Msg2 (e.g., RAR) is not received within the RAR window, the UE 115 may send Msg1 again with a power boost.

[0103] After the base station 105 sends Msg2, the UE 115 may monitor the PDCCH for a downlink control information (DCI) message (e.g., DCI 1_0 format) scrambled with the RA-RNTI (e.g., corresponding to the RACH opportunity used to send Msg1), and if detected, may proceed with PDSCH decoding. If a MAC-CE is found in the PDSCH corresponding to the preamble used by the UE 115 to send Msg1, the UE 115 may recognize that the MAC-CE is for the UE 115, and may follow the uplink grant (e.g., indicated by the MAC-CE) to send an identifier (ID) for the UE 115 (e.g., UE-ID) in Msg3 of the RACH procedure. For example, the UE 115 may then send an RRC connection request (e.g., Msg3) along with a temporary mobile subscriber identity (TMSI) (if the UE 115 has previously been connected to the same wireless network) or a random identifier. The RRC connection request may also indicate the reason why the UE 115 is connected to the network (e.g., emergency, signaling, data exchange, etc.). In some cases, if multiple UEs 115 use the same preamble sequence to send corresponding Msg1 in the same RACH opportunity, the base station 105 may encounter conflicts from multiple UEs 115. In addition, multiple UEs may also send Msg3 on the same resource, thereby causing conflicts or contention at the base station 105. Therefore, the base station 105 can respond to the connection request with a contention resolution message (e.g., the fourth message (Msg4)) addressed to the UE 115, and the contention resolution message can provide a new C-RNTI. If the UE 115 receives the contention resolution message with the correct identity, the UE 115 can continue with the RRC establishment. If the UE 115 does not receive the contention resolution message (e.g., if there is a conflict with another UE 115), the UE 115 can repeat the RACH process by sending a new RACH preamble. This message exchange between the UE 115 and the base station 105 for random access can be referred to as a four-step RACH process.

[0104] In other examples, a two-step RACH process for random access may be performed. For example, a wireless device operating in a licensed or unlicensed spectrum within the wireless communication system 100 may initiate a two-step RACH process to reduce delays in establishing communications with the base station 105 (e.g., compared to a four-step RACH process). In some cases, the two-step RACH process may operate regardless of whether the wireless device (e.g., UE 115) has a valid TA. For example, the UE 115 may use the valid TA to coordinate the timing of its transmissions to the base station 105 (e.g., to account for propagation delays), and may receive the valid TA (as part of the two-step RACH process). In addition, the two-step RACH process may be applicable to any cell size, may work regardless of whether the RACH process is contention-based or contention-free, and may combine multiple RACH messages from a four-step RACH process. For example, the two-step RACH process may include: a first message (e.g., message A (MsgA)) combining Msg1 and Msg3 of the four-step RACH process, and a second message (e.g., message B (MsgB)) combining Msg2 and Msg4 of the four-step RACH process.

[0105] The two-step RACH procedure may be applicable to any cell size supported in the wireless communication system, may operate regardless of whether the UE 115 has a valid TA, and may be applied to any RRC state of the UE 115 (e.g., idle state (RRCIDLE), inactive state (RRC_INACTIVE), connected state (RRC_CONNECTED), etc.). In some cases, the two-step RACH procedure may result in a reduction in signaling overhead and latency, enhanced RACH capacity, power savings for the UE 115, and provide synergy with other applications (e.g., positioning, mobility enhancement, etc.).

[0106] In some network deployment scenarios (e.g., for NR), the two-step RACH process and the four-step RACH process can be used simultaneously to meet different conditions of the system. For example, different conditions may include capacity conditions, delay conditions, reliability conditions, implementation complexity specifications, and the like. Therefore, different transmission opportunities that can be used for two RACH processes or any RACH process can be defined. For example, different transmission opportunities may include RACH opportunities and uplink shared channel opportunities (e.g., PUSCH opportunities). The RACH opportunity may include time and frequency resources allocated for physical RACH (PRACH) transmission. In addition, up to 64 preamble sequences may be configured for each RACH opportunity. In some cases, the two-step RACH process may use a RACH opportunity separate from the four-step RACH process, or may share a RACH opportunity with the four-step RACH process but use a different set of preamble sequences. Additionally or alternatively, the uplink shared channel opportunity (e.g., PUSCH opportunity) may include time and frequency resources allocated for MsgAPUSCH transmission (e.g., for transmission associated with the four-step RACH process).

[0107] In some cases, the first message of the RACH process (e.g., Msg1, Msg2, RACH preamble, PRACH, PRACH preamble, etc.) may provide a bottleneck (e.g., slow down, increase latency, delay, etc.) when the UE 115 uses inefficient transmission parameters to send the first RACH message or a combination thereof to establish communication based on the base station 105 not successfully receiving the first RACH message. In some cases, to alleviate the bottleneck, the UE 115 may use PRACH repetition or may use a different PRACH format for the first RACH message to increase PRACH coverage, or both. In addition, the base station 105 may use beam refinement to enhance the coverage of the PDCCH transmission as part of the second message transmission of the RACH process (e.g., Msg2, MsgB, RAR, etc.) and for subsequent messages. However, the use of these PRACH enhancements or other enhancements may increase the use of PRACH resources and may waste PRACH resources of the UE 115 in situations where the enhancements may be unnecessary. Therefore, techniques are desired to improve coverage of first RACH messages and PRACH (eg, and general RACH procedures) without unduly increasing usage of PRACH resources.

[0108] The wireless communication system 100 may support efficient techniques for the UE 115 to send a first RACH message multiple times on corresponding RACH opportunities using the same preamble sequence or concatenated preamble sequences until a second RACH message (e.g., a RACH response) is received from the base station 105 in the RAR window. When the first RACH message is sent multiple times, the multiple instances of the first RACH message may include a preamble sequence selected from a subset of preamble sequences configured for such repeated first RACH message transmission schemes. For example, by using a subset of preamble sequences, the base station 105 may more easily detect, receive, and decode the first RACH message sent multiple times. In addition, the UE subset may use such a repeated first RACH message transmission scheme based on the link status (e.g., power measurement) between the UE and the base station, the exposure status of the UE, other measurements, etc. This repeated first RACH message transmission scheme may be used for the number of opportunities between receiving a first SSB (which is configured with a repeated first RACH message transmission scheme) and receiving a second SSB (which is configured with a different RACH process). In some cases, the number of opportunities to send the first RACH message may be configured by the base station 105.

[0109] Figure 2 An example of a wireless communication system 200 supporting repeated random access transmissions according to aspects of the present disclosure is shown. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100, or can be implemented by aspects of the wireless communication system 100. For example, the wireless communication system 200 can include a base station 105-a and a UE 115-a, which can be respectively as described in reference Figure 1 The examples of corresponding base stations 105 and UEs 115 are described. In some cases, UE 115-a may attempt to establish a connection with base station 105-a using a RACH procedure, such as reference Figure 1 As part of the RACH procedure, base station 105-a may send one or more downlink messages to UE 115-a on resources of downlink carrier 205, and UE 115-a may send one or more uplink messages to base station 105-a on resources of uplink carrier 210. Although shown as separate carriers, downlink carrier 205 and uplink carrier 210 may be a single carrier.

[0110] Prior to performing a RACH procedure, the base station 105-a may send RACH configuration information 215 on the downlink carrier 205. In some cases, the base station 105-a may send the RACH configuration information 215 as part of an SSB, a SIB (e.g., SIB1), a remaining minimum system information (RMSI), an additional system information (SI) message, etc. In addition, the RACH configuration information 215 may include a configuration for the UE 115-a to perform a RACH procedure within a plurality of occasions (e.g., RACH occasions). For example, as described herein, the RACH configuration information 215 may include information that enables the UE 115-a to send a random access request message 220 (e.g., a first message of a RACH procedure, Msg1, MsgA, a PRACH message, etc.) on the uplink carrier 210 during two or more of the plurality of occasions.

[0111] In some cases, the UE 115-a may determine a number of opportunities (e.g., a quantity) of multiple opportunities for sending the random access request message 220 based on the RACH configuration information 215. For example, the base station 105-a may determine a limit on the number of repetitions (e.g., a number of opportunities) for the UE to send the random access request message 220 based on a bandwidth used for the RACH process, a frequency range used for the RACH process, a spectrum used for the RACH process, or a combination thereof. The base station 105-a may then indicate the limit to the UE 115-a in the RACH configuration information 215. Additionally or alternatively, the UE 115-a may determine the number of opportunities for sending the random access request message 220 based on a pre-configuration for the UE 115-a (e.g., loaded into the UE 115-a).

[0112] In addition, the RACH configuration information 215 may include an indication of a RACH preamble subset that the UE 115-a may use when sending a random access request message 220 multiple times (e.g., the random access request message 220 is repeated). For example, the RACH preamble subset may include a portion of the total set of RACH preambles that can be used in a RACH process (e.g., up to 64 preamble sequences can be configured for a RACH process). The RACH preamble subset may be associated with repeated transmissions of a first RACH message. By using the RACH preamble subset, the base station 105-a may be configured to detect, combine, and decode random access request messages 220 sent during two or more occasions (e.g., the RACH preamble subset may reduce the complexity of PRACH detection at the base station 105-a).

[0113] Before sending the random access request message 220 within two or more occasions, the UE 115-a may first determine whether to send the random access request message 220 within two or more occasions. For example, not all UEs 115 attempting a RACH procedure may send the random access request message 220 during more than one occasion or using more than one occasion. Therefore, a subset of UEs 115 may send the random access request message 220 within two or more occasions as part of the RACH procedure. The UE 115-a may determine whether the UE 115-a is part of the subset of UEs 115 based on power measurements, exposure conditions of the UE 115-a (e.g., maximum permissible exposure (MPE)), other measurements, or a combination thereof.

[0114] For example, UE 115-a may perform power measurements (e.g., reference signal received power (RSRP) measurements, received signal strength indication (RSSI) measurements, signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), etc.) on synchronization signals (e.g., SSB, PSS, SSS, SIB, etc.) received from base station 105-a, and if the power measurement satisfies a threshold (e.g., the power measurement value is above or below the threshold), UE 115-a may determine to send a random access request message 220 within two or more opportunities. That is, if UE 115-a is far away from base station 105-a (e.g., or other factors such as interference cause power to drop), the power of the reference signal may be lower at UE 115-a, and therefore, UE 115-a may infer that uplink transmissions (e.g., including Msg1 and random access request message 220 transmissions) may also experience low-power reception at base station 105-a. Therefore, by sending the random access request message 220 within two or more opportunities, the UE 115-a can increase the likelihood that the random access request message 220 is successfully received and decoded by the base station 105-a to advance the RACH process, rather than retrying the random access request message transmission and restarting the RACH process.

[0115] After determining to send the random access request message 220 within two or more occasions, the UE 115-a may use the same RACH preamble or concatenated RACH preamble sequence to send the random access request message 220 within two or more occasions on the corresponding RACH occasions (e.g., repeated PRACH transmissions) until a RAR (e.g., Msg2, MsgB, etc.) is received from the base station 105-a in the RAR window (e.g., after the last repetition). Therefore, the UE 115-a may select the same RACH preamble or concatenated RACH preamble sequence from the subset of RACH preambles that can be used to send random access request message 220 repetitions indicated to the UE 115-a in the RACH configuration information 215 for sending the random access request message 220 during the two or more occasions.

[0116] As shown, the UE 115-a may transmit a first random access request message 220-a (e.g., a first instance) during a first opportunity, a second random access request message 220-b (e.g., a second instance) during a second opportunity, a third random access request message 220-c (e.g., a third instance) during a third opportunity, and a fourth random access request message 220-d (e.g., a fourth instance) during a fourth opportunity. Although four (4) instances of the random access request message 220 are shown being transmitted, the UE 115-a may transmit any number of instances of the random access request message 220 (e.g., two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, etc.) in a corresponding number of opportunities based on the RACH configuration information 215. For example, as part of this illustrated example in the wireless communication system 200, the RACH configuration information 215 may instruct the UE 115-a to transmit the random access request message 220 in four (4) opportunities (e.g., four (4) repetitions). In addition, UE 115-a can continue to send random access request messages 220 according to the repetition scheme until the next SSB is received from base station 105-a. For example, UE 115-a can use RACH configuration information 215 to send random access request messages 220 in two or more opportunities until a subsequent RACH configuration is received from base station 105-a.

[0117] In some cases, the UE 115-a may utilize the same selected RACH preamble sequence from the indicated RACH preamble subset to transmit each random access request message 220. Additionally or alternatively, the UE 115-a may utilize a concatenated RACH preamble sequence to transmit each random access request message 220. That is, the UE 115-a may select a RACH preamble sequence to use for transmitting each random access request message 220, and may apply a different shift (e.g., a cyclic shift) to the selected RACH preamble sequence for each random access request message 220. For example, the UE 115-a may apply a first shift to the selected RACH preamble sequence when sending a first random access request message 220-a, a second shift to the selected RACH preamble sequence when sending a second random access request message 220-b, a third shift to the selected RACH preamble sequence when sending a third random access request message 220-c, and a fourth shift to the selected RACH preamble sequence when sending a fourth random access request message 220-d. Additionally or alternatively, the UE 115-a may select a different RACH preamble sequence from the indicated RACH preamble subset for each random access request message 220 transmission (e.g., a first RACH preamble sequence for the first random access request message 220-a, a second RACH preamble sequence for the second random access request message 220-b, and so on).

[0118] Subsequently, the base station 105-a may use (e.g., apply) a different beam to receive each random access request message 220 from the UE 115-a (e.g., each repetition). For example, the different beams used by the base station 105-a to receive each random access request message 220 may include different refinements of the associated SSB beam (e.g., for sending synchronization information or other information to the UE 115-a). The base station 105-a may combine each received random access request message 220 to successfully receive and decode the random access request message 220. If the base station 105-a successfully receives and decodes the random access request message 220 (e.g., based on each repetition), the base station 105-a may continue to send RARs 225 (e.g., a second RACH message, Msg2, MsgB, etc.) to the UE 115-a.

[0119] The base station 105-a may send a RAR within a RAR window configured for a RACH procedure and for the UE 115-a. In some cases, the length of the RAR window may be different when the UE 115-a sends a random access request message 220 during or using two or more occasions (e.g., PRACH repetitions, random access request message 220 repetitions, etc.) compared to when the UE 115-a sends a random access request message 220 once. For example, the base station 105-a may configure two different RAR window lengths, such as a first RAR window length for random access request message 220 repetitions and a second RAR window length for a single random access request message 220 transmission. In some cases, the base station 105-a may send an indication of the RAR window length in the RACH configuration information 215 or in a separate configuration message. For example, the UE 115-a may identify two different RAR window lengths (e.g., based on a table defined for a RACH procedure) from a single bit field in a system information message. In addition, the base station 105-a can determine the RAR window length used when the UE 115-a sends a random access request message 220 during two or more occasions (e.g., PRACH repetition, random access request message 220 repetition, etc.) based on the RAR window length used when the UE 115-a sends a random access request message 220 once, the bandwidth used for the RACH process, the frequency range used for the RACH process, the spectrum used for the RACH process, or a combination thereof.

[0120] Based on the RAR window length used when the UE 115-a sends the random access request message 220 during two or more occasions, the UE 115-a may identify when to send each instance of the random access request message 220. For example, the UE 115-a may send a first random access request message 220-a during a first occasion, wait for a duration equal to the RAR window length, send a second random access request message 220-b during a second occasion after the duration of the RAR window length expires, wait for a duration equal to the RAR window length, send a third random access request message 220-c during a third occasion after the duration of the RAR window length expires, and so on. After the UE 115-a sends the last random access request message 220 (e.g., the last repetition), the UE 115-a may monitor the RAR 225 during the RAR window according to the RAR window length. Additionally or alternatively, the UE 115-a may monitor the RAR 225 from the base station 105-a during each corresponding RAR window after each corresponding random access request message 220 transmission. If RAR 225 is detected and received, UE 115-a may continue to send a third RACH message to base station 105-a to continue the RACH process. If RAR 225 is not detected or successfully received, UE 115-a may again send a random access request message 220 to base station 105-a (e.g., using a repetition scheme described herein, a different repetition scheme, a single time, etc.) to retry the RACH process.

[0121] Figure 3 An example of a repeated random access transmission configuration 300 according to aspects of the present disclosure is shown. In some examples, the repeated random access transmission configuration 300 can implement aspects of the wireless communication system 100, the wireless communication system 200, or both, or can be implemented by aspects of the wireless communication system 100, the wireless communication system 200, or both. For example, the base station 105 and the UE 115 can use the repeated random access transmission configuration 300 as part of a RACH procedure to establish a connection between the base station 105 and the UE 115. Therefore, as described herein, the UE 115 can send a first RACH message (e.g., a random access request message, Msg1, MsgA, etc.) of the RACH procedure during two or more opportunities to increase the chance that the base station 105 successfully receives and decodes the first RACH message.

[0122] The UE 115 may use the RACH preamble subset 305 to send a random access request 310 during two or more occasions. The random access request 310 may be a first RACH message, and the UE 115 may send multiple instances of the random access request 310 during the respective occasions. In addition, the RACH preamble subset 305 at the beginning of each instance of the random access request 310 may be the same preamble, a concatenated preamble (e.g., a different shift applied to the same preamble), or a different preamble. The UE 115 may determine when to send each instance of the random access request 310 based on the length of the RAR window 315. For example, the base station 105 may configure the length of the RAR window 315 for the repeated random access transmission configuration 300 (e.g., for when the UE 115 sends the random access request 310 within two or more occasions), and indicate the length to the UE 115 (e.g., in a RACH configuration information message).

[0123] For example, as shown, UE 115 may send a first instance of a random access request 310 (e.g., with a RACH preamble selected from RACH preamble subset 305). Subsequently, UE 115 may then send a second instance of the random access request 310 after expiration of the first RAR window 315-a, a third instance of the random access request 310 after expiration of the second RAR window 315-b, and a fourth instance of the random access request 310 after expiration of the third RAR window 315-c.

[0124] In some cases, the UE 115 may monitor each RAR window 315 for a RAR sent by the base station 105 in response to the transmission of the random access request 310. Additionally or alternatively, the UE 115 may not monitor the RAR window 315 for a RAR until the last instance of the random access request 310 is sent in the final opportunity. For example, if the fourth instance of the random access request 310 is the last instance and the final opportunity, the UE 115 may monitor the RAR during the fourth RAR window 315-d that occurs after the transmission of the fourth instance of the random access request 310. Thus, the UE 115 may use the monitoring process to monitor a single RAR window 315 or to monitor multiple RAR windows 315 during a repeating segment of the RAR window 315.

[0125] Additionally, the UE 115 may use the repeated random access transmission configuration 300 for a duration 320. For example, the duration 320 may include a length of time between receiving a first SSB carrying configuration information for the repeated random access transmission configuration 300 and receiving a second SSB carrying updated or additional configuration information for the repeated random access transmission configuration 300.

[0126] Figure 4 An example of a process flow 400 for supporting repeated random access transmissions according to aspects of the present disclosure is shown. In some examples, the process flow 400 can implement aspects of the wireless communication system 100, the wireless communication system 200, or both, or can be implemented by aspects of the wireless communication system 100, the wireless communication system 200, or both. For example, the process flow 400 may include a base station 105-b and a UE 115-b, which may be examples of corresponding base stations 105 and UE 115, respectively, as described in reference to Figure 1-3 As described.

[0127] In the following description of process flow 400, operations between UE 115-b and base station 105-b may be sent in a different order than shown, or operations performed by base station 105-b and UE 115 may be performed in a different order or at a different time. Some operations may also be excluded from process flow 400, or other operations may be added to process flow 400. Base station 105-b and UE 115-b are shown as performing some operations of process flow 400, and in some cases, any wireless device may perform the operations shown.

[0128] At 405, UE 115-b may receive configuration information from base station 105-b for performing a random access procedure (e.g., a RACH procedure) with base station 105-b within a set of opportunities associated with the configuration information. In some cases, UE 115-b may receive the configuration information via an SSB, a SIB (e.g., SIB1), system information (e.g., an RMSI message, an SI message, etc.), or a combination thereof. Additionally, the set of opportunities may occur between receiving a first SSB carrying the configuration information and receiving a second SSB carrying additional configuration information.

[0129] At 410, UE 115-b may receive information from base station 105-b indicating a subset of random access preamble codes (e.g., RACH preamble codes) associated with sending a random access request message (e.g., a repetition of a random access request message) within two or more occasions in a set of occasions, wherein the random access preamble code subset is indicated from a set of random access preamble codes that can be used for a random access process.

[0130] Subsequently, UE 115-b may select a random access preamble from the subset of random access preambles, wherein different instances of the random access request message (e.g., a first instance, a second instance, etc.) are sent together with the selected random access preamble. In some cases, UE 115-a may apply a different cyclic shift to the random access preamble (e.g., a linked random access preamble) for each instance of sending a random access request message. Additionally or alternatively, UE 115-b may select a different random access preamble for each instance of sending a random access request. For example, UE 115-b may select a first random access preamble from the subset of random access preambles for transmitting a first instance of the random access request message during a first opportunity, and may select a second random access preamble from the subset of random access preambles for transmitting a second instance of the random access request message during a second opportunity.

[0131] At 415, UE 115-b may receive information from base station 105-b indicating a first length of a time window associated with sending a random access request message within two or more occasions in a set of occasions, and a second length of a time window associated with sending a random access request message at a single occasion in the set of occasions. In some cases, the time window may be used to transmit a RAR for a random access procedure to UE 115-b, and the first length may be shorter than the second length. UE 115-b may determine the first length of the time window and the second length of the time window based on a single bit field in the information, a time window length table, or a combination thereof. In addition, the first length of the time window may be based on the second length of the time window, a frequency range used for a random access procedure, a frequency band used for a random access procedure, or a combination thereof.

[0132] At 420, UE 115-b may determine, based on a condition of a communication link between UE 115-b and base station 105-b, to send a random access request message for a random access procedure during two or more occasions in a set of occasions. In some cases, UE 115-b may determine, based on configuration information, a number (e.g., quantity) of occasions in a set of occasions for sending a random access request message. In addition, the number of opportunities for sending a random access request message may be based on a bandwidth for performing a random access procedure, a frequency range for a random access procedure, a spectrum band for a random access procedure, or a combination thereof.

[0133] In some cases, UE 115-b may use the configuration information to perform power measurements associated with the communication link and may determine that the power measurements satisfy a threshold, wherein a determination to send a random access request message during two or more occasions is based on the power measurements satisfying the threshold. For example, the power measurements may include RSRP measurements, RSSI measurements, different measurements, or a combination thereof. Additionally or alternatively, UE 115-b may identify an exposure condition (e.g., an MPE condition) of UE 115-b, wherein a determination to send a random access request message during two or more occasions is based on the exposure condition of the UE.

[0134] At 425 , UE 115 - b may send a first instance of a random access request message during a first opportunity in the set of opportunities.

[0135] At 430, UE 115-b may send a second instance of the random access request message during a second opportunity in the set of opportunities based on determining to send the random access request message during two or more opportunities in the set of opportunities. In some cases, the first instance of the random access request message may be sent before a first time window having a first length (as described in 415), and the second instance of the random access request message may be sent after the first time window associated with the first instance expires according to the first length.

[0136] Base station 105-b may select a first beam to receive a first instance of the random access request message and may select a second beam to receive a second instance of the random access request message, wherein the second beam is different from the first beam. In some cases, the first beam and the second beam may be different based on a beam refinement process.

[0137] At 435, the base station 105-b may attempt to receive and decode the random access request message (e.g., determine the random access request message) based on receiving the first instance and the second instance of the random access request message. For example, the base station 105-b may combine the first instance and the second instance to fully receive and decode the random access request message.

[0138] At 440, the UE 115-b may monitor for a random access response of a random access procedure after sending a last instance of the random access request message, wherein the random access response is monitored during a time window according to a first length. For example, the base station 105-b may send a random access response of the random access procedure to the UE 115-b during a time window configured for transmitting the random access response. In some cases, the base station 105-b may send a random access response based on receiving a first instance and a second instance of the random access request message during two or more occasions in the set of occasions.

[0139] Figure 5 A block diagram 500 of a device 505 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The device 505 may be an example of aspects of a UE 115 as described herein. The device 505 may include a receiver 510, a UE communication manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0140] The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repeated random access transmissions, etc.). The information may be transmitted to other components of the device 505. The receiver 510 may be a reference Figure 8 Examples of aspects of the described transceiver 820. The receiver 510 may utilize a single antenna or a group of antennas.

[0141] The UE communication manager 515 may receive configuration information from the base station for performing a random access procedure with the base station within a timing set associated with the configuration information. In some cases, the UE communication manager 515 may determine to send a random access request message for the random access procedure during two or more timings in the timing set based on the status of the communication link between the UE and the base station. In addition, the UE communication manager 515 may send a first instance of the random access request message during a first timing in the timing set and send a second instance of the random access request message during a second timing in the timing set based on determining to send the random access request message during two or more timings in the timing set. The UE communication manager 515 may be an example of various aspects of the UE communication manager 810 described herein.

[0142] In some examples, the UE communication manager 515 as described herein may be implemented to achieve one or more potential advantages for the UE 115. For example, based on sending at least a first instance and a second instance of a random access request message during corresponding opportunities, the UE communication manager 515 may enable the UE 115 to perform a RACH procedure more efficiently. Multiple instances (e.g., repetitions) of the random access request message may enable the base station 105 to have a higher probability of successfully receiving and decoding the random access request message, thereby reducing the latency of the RACH procedure and potentially alleviating additional RACH procedures to be performed to establish a connection between the UE 115 and the base station 105. In addition, if the random access request message is not successfully received or decoded at the base station 105, the UE communication manager 515 may reduce the signaling overhead that may be caused by retrying the RACH procedure.

[0143] The UE communication manager 515 or its subcomponents may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. When implemented in code executed by a processor, the functions of the UE communication manager 515 or its subcomponents may be performed by a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any combination thereof designed to perform the functions described in the present disclosure.

[0144] The UE communication manager 515 or its subcomponents may be physically located at various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the UE communication manager 515 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the UE communication manager 515 or its subcomponents may be combined with one or more other hardware components, including but not limited to: an input / output (I / O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0145] The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be co-located with the receiver 510 in a transceiver component. For example, the transmitter 520 may be a reference Figure 8 Examples of aspects of the described transceiver 820. The transmitter 520 may utilize a single antenna or a group of antennas.

[0146] Figure 6 A block diagram 600 of a device 605 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The device 605 may be an example of aspects of the device 505 or UE 115 as described herein. The device 605 may include a receiver 610, a UE communication manager 615, and a transmitter 635. The device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0147] The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repeated random access transmissions, etc.). The information may be transmitted to other components of the device 605. The receiver 610 may be a reference Figure 8 Examples of aspects of the described transceiver 820. The receiver 610 may utilize a single antenna or a group of antennas.

[0148] UE communication manager 615 may be an example of aspects of UE communication manager 515 as described herein. UE communication manager 615 may include RACH configuration component 620, RACH repetition determination component 625, and RACH request component 630. UE communication manager 615 may be an example of aspects of UE communication manager 810 described herein.

[0149] RACH configuration component 620 may receive configuration information from a base station for performing a random access procedure with the base station within a set of occasions associated with the configuration information.

[0150] The RACH repetition determining component 625 may determine to send a random access request message of a random access procedure during two or more opportunities in the opportunity set based on the status of the communication link between the UE and the base station.

[0151] RACH request component 630 can send a first instance of the random access request message during a first opportunity in the set of opportunities and send a second instance of the random access request message during a second opportunity in the set of opportunities based on determining to send a random access request message during two or more opportunities in the set of opportunities.

[0152] Based on the techniques for sending the first and second instances of the random access request message, the processor of the UE 115 (e.g., a processor that controls the receiver 610, the transmitter 635, or a processor that controls the random access request message) may be configured to receive the random access request message from the UE 115. Figure 8 The transceiver 820 described herein can reduce delays and signaling overhead caused by the following situation: if the random access request message is sent in one instance during a single opportunity, the base station 105 does not receive the random access request message. For example, multiple instances of the random access request message can enable the base station 105 to combine different instances to increase the probability that the random access request message is successfully decoded. Therefore, the base station 105 and the UE 115 can have a higher probability of establishing a connection in a single RACH process, rather than retrying the RACH process or resending different RACH messages, thereby reducing delays and reducing signaling overhead.

[0153] The transmitter 635 can transmit signals generated by other components of the device 605. In some examples, the transmitter 635 can be co-located with the receiver 610 in a transceiver component. For example, the transmitter 635 can be a reference Figure 8 Examples of aspects of the described transceiver 820. The transmitter 635 may utilize a single antenna or a group of antennas.

[0154] Figure 7A block diagram 700 of a UE communication manager 705 supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown. The UE communication manager 705 may be an example of aspects of the UE communication manager 515, the UE communication manager 615, or the UE communication manager 810 described herein. The UE communication manager 705 may include a RACH configuration component 710, a RACH repetition determination component 715, a RACH request component 720, a RACH preamble selection component 725, a RAR window length component 730, and a number of opportunities determination component 735. Each of these components may be in communication with each other directly or indirectly (e.g., via one or more buses).

[0155] The RACH configuration component 710 may receive configuration information from a base station for performing a random access procedure with the base station within a timing set associated with the configuration information. In some cases, the configuration information may be received via an SSB, a SIB, system information, or a combination thereof. Additionally, the timing set may occur between receiving a first SSB carrying the configuration information and receiving a second SSB carrying additional configuration information.

[0156] The RACH repetition determination component 715 can determine, based on the status of the communication link between the UE and the base station, to send a random access request message for a random access process during two or more opportunities in the opportunity set. In some examples, the RACH repetition determination component 715 can use configuration information to perform power measurements associated with the communication link, and can determine that the power measurement meets a threshold, wherein the determination to send a random access request message during two or more opportunities is based on the power measurement meeting the threshold. In some cases, the power measurement may include an RSRP measurement, an RSSI measurement, or a combination thereof. Additionally or alternatively, the RACH repetition determination component 715 can identify the exposure status of the UE, wherein the determination to send a random access request message during two or more opportunities is based on the exposure status of the UE.

[0157] RACH request component 720 can send a first instance of the random access request message during a first opportunity in the set of opportunities and send a second instance of the random access request message during a second opportunity in the set of opportunities based on determining to send a random access request message during two or more opportunities in the set of opportunities.

[0158] The RACH preamble selection component 725 may receive information from a base station indicating a subset of random access preambles associated with sending a random access request message within two or more occasions in a set of occasions, the random access preamble subset being indicated from a set of random access preambles available for a random access procedure, wherein determining to send the random access request message during the two or more occasions is based on the received information. In some examples, the RACH preamble selection component 725 may select a random access preamble from the subset of random access preambles, wherein sending a first instance and a second instance of the random access request message during the first occasion and the second occasion includes sending the random access preamble. In some cases, a different cyclic shift may be applied to the random access preamble for each instance of sending the random access request message.

[0159] Additionally or alternatively, the RACH preamble selection component 725 may select a first random access preamble for a first opportunity from a subset of random access preambles, wherein a first instance of sending a random access request message during the first opportunity includes sending the first random access preamble, and may select a second random access preamble for a second opportunity from the subset of random access preambles, wherein a second instance of sending a random access request message during the second opportunity includes sending the second random access preamble.

[0160] The RAR window length component 730 may receive information from a base station indicating a first length of a time window associated with sending a random access request message within two or more opportunities in a set of opportunities, and a second length of a time window associated with sending a random access request message at a single opportunity in the set of opportunities. In some cases, the time window may be used to transmit a RAR for a random access procedure to a UE, and the first length may be shorter than the second length. In some examples, the RAR window length component 730 may monitor the RAR for a random access procedure after a last instance of sending a random access request message, wherein the RAR is monitored during the time window according to the first length.

[0161] In addition, the RAR window length component 730 can determine the first length of the time window and the second length of the time window based on a single bit field in the information, a time window length table, or a combination thereof. In some cases, the first instance of the random access request message can be sent before the first time window having the first length, and the second instance of the random access request message can be sent after the first time window associated with the first instance expires according to the first length. In some cases, the first length of the time window can be based on the second length of the time window, the frequency range used for the random access procedure, the frequency band used for the random access procedure, or a combination thereof.

[0162] The opportunity number determination component 735 can determine the number of opportunities of the opportunity set for sending the random access request message based on the configuration information, wherein determining to send the random access request message during two or more opportunities is based on determining the number of opportunities. In some cases, the number of opportunities for sending the random access request message can be based on a bandwidth for performing a random access procedure, a frequency range for a random access procedure, a spectrum band for a random access procedure, or a combination thereof.

[0163] Figure 8 A diagram of a system 800 including a device 805 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The device 805 may be an example of a device 505, a device 605, or a UE 115 as described herein, or include components of the device 505, the device 605, or a UE 115. The device 805 may include components for two-way voice and data communications, including components for sending communications and components for receiving communications, including a UE communications manager 810, an I / O controller 815, a transceiver 820, an antenna 825, a memory 830, and a processor 840. These components may be in electrical communication via one or more buses (e.g., a bus 845).

[0164] The UE communication manager 810 may receive configuration information from the base station for performing a random access procedure with the base station within a timing set associated with the configuration information. In some cases, the UE communication manager 810 may determine to send a random access request message for the random access procedure during two or more timings in the timing set based on a condition of a communication link between the UE and the base station. In addition, the UE communication manager 810 may send a first instance of the random access request message during a first timing in the timing set and send a second instance of the random access request message during a second timing in the timing set based on determining to send the random access request message during two or more timings in the timing set.

[0165] I / O controller 815 can manage input and output signals for device 805. I / O controller 815 can also manage peripheral devices that are not integrated into device 805. In some cases, I / O controller 815 can represent a physical connection or port for external peripheral devices. In some cases, I / O controller 815 can utilize an operating system, such as Or another known operating system. In other cases, I / O controller 815 can represent a modem, keyboard, mouse, touch screen or similar device, or interact with these devices. In some cases, I / O controller 815 can be implemented as a part of a processor. In some cases, a user can interact with device 805 via I / O controller 815 or via hardware components controlled by I / O controller 815.

[0166] The transceiver 820 can communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 820 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 820 can also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0167] In some cases, a wireless device may include a single antenna 825. However, in some cases, a device may have more than one antenna 825 that can simultaneously send or receive multiple wireless transmissions.

[0168] The memory 830 may include random access memory (RAM) and read-only memory (ROM). The memory 830 may store computer-readable, computer-executable code 835 including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, the memory 830 may contain, among other things, a basic I / O system (BIOS) that may control basic hardware or software operations (e.g., interaction with peripheral components or devices).

[0169] The processor 840 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, a separate gate or transistor logic component, a separate hardware component, or any combination thereof). In some cases, the processor 840 may be configured to operate the memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks that support repeated random access transmissions).

[0170] The code 835 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 835 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 835 may not be directly executable by the processor 840, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0171] Fig. 9 A block diagram 900 of a device 905 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The device 905 may be an example of aspects of a base station 105 as described herein. The device 905 may include a receiver 910, a base station communication manager 915, and a transmitter 920. The device 905 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0172] The receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repeated random access transmissions, etc.). The information may be transmitted to other components of the device 905. The receiver 910 may be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The receiver 910 may utilize a single antenna or a group of antennas.

[0173] The base station communication manager 915 may send configuration information to the UE for the UE to perform a random access procedure with the base station within a timing set associated with the configuration information. In some cases, the base station communication manager 915 may receive a first instance of a random access request message for a random access procedure from the UE during a first timing in the timing set. In addition, the base station communication manager 915 may receive a second instance of a random access request message for a random access procedure from the UE during a second timing in the timing set, the second timing occurring after the first timing. In some cases, the base station communication manager 915 sends a RAR for a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on the first instance and the second instance of the random access request message received during two or more timings in the timing set. The base station communication manager 915 may be an example of various aspects of the base station communication manager 1210 described herein.

[0174] The base station communication manager 915 or its subcomponents may be implemented in hardware, in code (e.g., software or firmware) executed by a processor, or any combination thereof. When implemented in code executed by a processor, the functions of the base station communication manager 915 or its subcomponents may be performed by a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

[0175] The base station communication manager 915 or its subcomponents may be physically located in various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the base station communication manager 915 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the base station communication manager 915 or its subcomponents may be combined with one or more other hardware components, including but not limited to: I / O components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0176] The transmitter 920 can transmit signals generated by other components of the device 905. In some examples, the transmitter 920 can be co-located with the receiver 910 in a transceiver component. For example, the transmitter 920 can be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The transmitter 920 may utilize a single antenna or a group of antennas.

[0177] Fig.10 A block diagram 1000 of a device 1005 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The device 1005 may be an example of aspects of the device 905 or base station 105 as described herein. The device 1005 may include a receiver 1010, a base station communication manager 1015, and a transmitter 1040. The device 1005 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0178] The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to repeated random access transmissions, etc.). The information may be transmitted to other components of the device 1005. The receiver 1010 may be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The receiver 1010 may utilize a single antenna or a group of antennas.

[0179] The base station communication manager 1015 may be an example of aspects of the base station communication manager 915 as described herein. The base station communication manager 1015 may include a RACH configuration indicator 1020, a RACH request instance component 1025, an additional RACH request instance component 1030, and a RAR component 1035. The base station communication manager 1015 may be an example of aspects of the base station communication manager 1210 described herein.

[0180] The RACH configuration indicator 1020 may send configuration information to the UE, so that the UE may perform a random access procedure with the base station within a timing set associated with the configuration information.

[0181] The RACH request instance component 1025 can receive a first instance of a random access request message for a random access procedure from a UE during a first opportunity in a set of opportunities.

[0182] The additional RACH request instance component 1030 can receive a second instance of a random access request message for a random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity.

[0183] The RAR component 1035 may send a RAR of a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving a first instance and a second instance of a random access request message during two or more occasions in the set of occasions.

[0184] The transmitter 1040 can transmit signals generated by other components of the device 1005. In some examples, the transmitter 1040 can be co-located with the receiver 1010 in a transceiver component. For example, the transmitter 1040 can be a reference Fig.12 Examples of various aspects of the described transceiver 1220. The transmitter 1040 may utilize a single antenna or a group of antennas.

[0185] Fig.11A block diagram 1100 of a base station communication manager 1105 supporting repeated random access transmissions in accordance with aspects of the present disclosure is shown. The base station communication manager 1105 can be an example of aspects of the base station communication manager 915, the base station communication manager 1015, or the base station communication manager 1210 described herein. The base station communication manager 1105 can include a RACH configuration indicator 1110, a RACH request instance component 1115, an additional RACH request instance component 1120, a RAR component 1125, a RACH preamble indicator 1130, a RAR window length indicator 1135, a RACH request opportunity number component 1140, and a beam selection component 1145. Each of these components can communicate directly or indirectly with each other (e.g., via one or more buses).

[0186] The RACH configuration indicator 1110 may send configuration information to the UE for the UE to perform a random access procedure with the base station within a timing set associated with the configuration information. In some cases, the configuration information may be sent via an SSB, a SIB, system information, or a combination thereof. In addition, the timing set may occur between sending a first SSB carrying the configuration information and sending a second SSB carrying additional configuration information.

[0187] The RACH request instance component 1115 can receive a first instance of a random access request message for a random access procedure from a UE during a first opportunity in a set of opportunities.

[0188] The additional RACH request instance component 1120 may receive a second instance of a random access request message for a random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity. In some examples, the additional RACH request instance component 1120 may determine that the UE is to send a random access request message within two or more opportunities in the set of opportunities, wherein the first instance and the second instance of the random access request message are received based on determining that the UE is to send a random access request message within two or more opportunities in the set of opportunities. In some cases, determining that the UE is to send a random access request message within two or more opportunities in the set of opportunities may be based on power measurements, exposure conditions of the UE, or a combination thereof.

[0189] The RAR component 1125 may send a RAR of a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving a first instance and a second instance of a random access request message during two or more occasions in the set of occasions.

[0190] The RACH preamble indicator 1130 may send information indicating a random access preamble subset associated with the UE sending a random access request message within two or more opportunities in the opportunity set to the UE, the random access preamble subset being indicated from a set of random access preambles that can be used for a random access procedure. In some cases, the first instance and the second instance of the random access request message may be received with the same random access preamble or different random access preambles. Additionally or alternatively, the first instance of the random access request message may be received with a random access preamble to which a first cyclic shift is applied, and the second instance of the random access request message may be received with a random access preamble to which a second cyclic shift is applied.

[0191] The RAR window length indicator 1135 may send information to the UE indicating a first length of a time window associated with the UE sending a random access request message within two or more occasions in the opportunity set, and a second length of a time window associated with the UE sending a random access request message at a single opportunity in the opportunity set, wherein the first length is shorter than the second length. In some examples, the RAR window length indicator 1135 may determine the first length of the time window based on the second length of the time window, the frequency range used for the random access procedure, the frequency band used for the random access procedure, or a combination thereof. In some cases, the first length of the time window and the second length of the time window may be indicated based on a single bit field in the signaling, a time window length table, or a combination thereof. In addition, the second instance of the random access request message may be received after the first instance of the random access request message according to the first length.

[0192] The RACH request opportunity number component 1140 can determine a number of opportunities for the UE to send a random access request message, where the number of opportunities is based on a bandwidth used to perform a random access procedure, a frequency range used for a random access procedure, a frequency band used for a random access procedure, or a combination thereof. In some examples, the RACH request opportunity number component 1140 can send an indication of the number of opportunities to the UE in a configuration message.

[0193] The beam selecting component 1145 can select a first beam to receive a first instance of the random access request message. In some examples, the beam selecting component 1145 can select a second beam to receive a second instance of the random access request message, the second beam being different from the first beam. In some cases, the first beam and the second beam can be different based on a beam refinement process.

[0194] Fig.12A diagram of a system 1200 including a device 1205 supporting repeated random access transmissions according to aspects of the present disclosure is shown. The device 1205 may be an example of a device 905, a device 1005, or a base station 105 as described herein, or include components of the device 905, the device 1005, or the base station 105. The device 1205 may include components for two-way voice and data communications, including components for sending communications and components for receiving communications, including a base station communication manager 1210, a network communication manager 1215, a transceiver 1220, an antenna 1225, a memory 1230, a processor 1240, and an inter-station communication manager 1245. These components may be in electrical communication via one or more buses (e.g., a bus 1250).

[0195] The base station communication manager 1210 may send configuration information to the UE for the UE to perform a random access procedure with the base station within a timing set associated with the configuration information. In some cases, the base station communication manager 1210 may receive a first instance of a random access request message for a random access procedure from the UE during a first timing in the timing set. In addition, the base station communication manager 1210 may receive a second instance of a random access request message for a random access procedure from the UE during a second timing in the timing set, the second timing occurring after the first timing. In some cases, the base station communication manager 1210 may send a RAR for a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving the first instance and the second instance of the random access request message during two or more timings in the timing set.

[0196] The network communications manager 1215 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 1215 may manage the transmission of data communications for client devices (eg, one or more UEs 115).

[0197] The transceiver 1220 can communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 1220 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 1220 can also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0198] In some cases, a wireless device may include a single antenna 1225. However, in some cases, a device may have more than one antenna 1225 that can simultaneously send or receive multiple wireless transmissions.

[0199] Memory 1230 may include RAM, ROM, or a combination thereof. Memory 1230 may store computer readable code 1235 including instructions that, when executed by a processor (e.g., processor 1240), cause the device to perform various functions described herein. In some cases, memory 1230 may include, among other things, a BIOS that may control basic hardware or software operations (e.g., interactions with peripheral components or devices).

[0200] Processor 1240 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a separate gate or transistor logic component, a separate hardware component, or any combination thereof). In some cases, processor 1240 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into processor 1240. Processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause device 1205 to perform various functions (e.g., functions or tasks that support repeated random access transmissions).

[0201] The inter-station communication manager 1245 can manage communications with other base stations 105 and can include a controller or scheduler for controlling communications with UE 115 in cooperation with other base stations 105. For example, the inter-station communication manager 1245 can coordinate the scheduling of transmissions to UE 115 to implement various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-station communication manager 1245 can provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0202] The code 1235 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 1235 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 1235 may not be directly executable by the processor 1240, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0203] Fig.13 1 is a flow chart of a method 1300 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1300 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1300 may be implemented by a UE 115 or a component thereof as described herein. Figures 5 to 8The UE communication manager described herein may be used to perform. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0204] At 1305, the UE may receive configuration information from the base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1305 may be performed according to methods as described herein. In some examples, aspects of the operations of 1305 may be performed as described with reference to Figures 5 to 8 The described RACH configuration component is performed.

[0205] At 1310, the UE may determine, based on the status of the communication link between the UE and the base station, to send a random access request message of a random access procedure during two or more opportunities in the opportunity set. The operation of 1310 may be performed according to the method as described herein. In some examples, various aspects of the operation of 1310 may be performed as described with reference to Figures 5 to 8 The described RACH repetition determination component is performed.

[0206] At 1315, the UE may send a first instance of the random access request message during a first opportunity in the opportunity set and send a second instance of the random access request message during a second opportunity in the opportunity set based on determining to send a random access request message during two or more opportunities in the opportunity set. The operations of 1315 may be performed according to methods as described herein. In some examples, aspects of the operations of 1315 may be performed as described with reference to Figures 5 to 8 The described RACH request component is performed.

[0207] Fig.14 1400 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1400 may be implemented by the UE 115 or components thereof as described herein. For example, the operations of the method 1400 may be implemented by the UE 115 or components thereof as described herein. Figures 5 to 8 The UE communication manager described herein may be used to perform. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0208] At 1405, the UE may receive configuration information from the base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1405 may be performed according to methods as described herein. In some examples, aspects of the operations of 1405 may be performed as described with reference to Figures 5 to 8The described RACH configuration component is performed.

[0209] At 1410, the UE may determine, based on the status of the communication link between the UE and the base station, to send a random access request message of a random access procedure during two or more opportunities in the opportunity set. The operation of 1410 may be performed according to the method as described herein. In some examples, various aspects of the operation of 1410 may be performed as described with reference to Figures 5 to 8 The described RACH repetition determination component is performed.

[0210] At 1415, the UE may receive from the base station information indicating a random access preamble subset associated with sending a random access request message within two or more opportunities in the set of opportunities, the random access preamble subset being indicated from a set of random access preambles that may be used for a random access procedure, wherein determining to send the random access request message during the two or more opportunities is based on the received information. The operations of 1415 may be performed according to methods as described herein. In some examples, aspects of the operations of 1415 may be performed as described with reference to Figures 5 to 8 The described RACH preamble selection component is performed.

[0211] At 1420, the UE may send a first instance of the random access request message during a first opportunity in the opportunity set and send a second instance of the random access request message during a second opportunity in the opportunity set based on determining to send a random access request message during two or more opportunities in the opportunity set. The operations of 1420 may be performed according to methods as described herein. In some examples, aspects of the operations of 1420 may be performed as described with reference to Figures 5 to 8 The described RACH request component is performed.

[0212] Fig.15 1 is a flow chart of a method 1500 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1500 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1500 may be implemented by a UE 115 or a component thereof as described herein. Figures 5 to 8 The UE communication manager described herein may be used to perform. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0213] At 1505, the UE may receive configuration information from the base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1505 may be performed according to methods as described herein. In some examples, aspects of the operations of 1505 may be performed as described with reference to Figures 5 to 8 The described RACH configuration component is performed.

[0214] At 1510, the UE may determine, based on the status of the communication link between the UE and the base station, to send a random access request message of a random access procedure during two or more opportunities in the opportunity set. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be performed as described with reference to Figures 5 to 8 The described RACH repetition determination component is performed.

[0215] At 1515, the UE may use the configuration information to perform power measurements associated with the communication link. The operations of 1515 may be performed according to methods as described herein. In some examples, aspects of the operations of 1515 may be performed as described with reference to Figures 5 to 8 The described RACH repetition determination component is performed.

[0216] At 1520, the UE may determine that the power measurement satisfies a threshold, wherein determining to send a random access request message during two or more opportunities is based on the power measurement satisfying the threshold. The operations of 1520 may be performed according to methods as described herein. In some examples, aspects of the operations of 1520 may be performed as described with reference to Figures 5 to 8 The described RACH repetition determination component is performed.

[0217] At 1525, the UE may send a first instance of the random access request message during a first opportunity in the opportunity set and send a second instance of the random access request message during a second opportunity in the opportunity set based on determining to send a random access request message during two or more opportunities in the opportunity set. The operations of 1525 may be performed according to methods as described herein. In some examples, aspects of the operations of 1525 may be performed as described with reference to Figures 5 to 8 The described RACH request component is performed.

[0218] Fig.16 1 is a flow chart of a method 1600 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1600 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1600 may be implemented by a UE 115 or a component thereof as described herein. Figures 5 to 8 The UE communication manager described herein may be used to perform. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0219] At 1605, the UE may receive configuration information from the base station for performing a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1605 may be performed according to methods as described herein. In some examples, aspects of the operations of 1605 may be performed as described with reference to Figures 5 to 8 The described RACH configuration component is performed.

[0220] At 1610, the UE may determine, based on the status of the communication link between the UE and the base station, to send a random access request message of a random access procedure during two or more opportunities in the opportunity set. The operation of 1610 may be performed according to the method as described herein. In some examples, various aspects of the operation of 1610 may be performed as described with reference to Figures 5 to 8 The described RACH repetition determination component is performed.

[0221] At 1615, the UE may receive from the base station information indicating a first length of a time window associated with sending a random access request message in two or more opportunities in the opportunity set, and a second length of a time window associated with sending a random access request message in a single opportunity in the opportunity set, the time window being used to transmit a RAR of a random access procedure to the UE, and the first length being shorter than the second length. The operation of 1615 may be performed according to a method as described herein. In some examples, aspects of the operation of 1615 may be performed by referring to Figures 5 to 8 The described RACH window length component is performed.

[0222] At 1620, the UE may send a first instance of the random access request message during a first opportunity in the opportunity set and send a second instance of the random access request message during a second opportunity in the opportunity set based on determining to send a random access request message during two or more opportunities in the opportunity set. The operations of 1620 may be performed according to methods as described herein. In some examples, aspects of the operations of 1620 may be performed as described with reference to Figures 5 to 8 The described RACH request component is performed.

[0223] Fig.17 1700 is a flowchart of a method 1700 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1700 may be implemented by a base station 105 or a component thereof as described herein. For example, the operations of the method 1700 may be implemented by a base station 105 or a component thereof as described herein. Figures 9 to 12 The base station may be executed by the base station communication manager described in the foregoing. In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0224] At 1705, the base station may send configuration information to the UE for the UE to perform a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1705 may be performed according to methods as described herein. In some examples, aspects of the operations of 1705 may be performed as described with reference to Figures 9 to 12 The RACH configuration indicator described above is used to perform the above operation.

[0225] At 1710, the base station may receive a first instance of a random access request message for a random access procedure from a UE during a first opportunity in a set of opportunities. The operations of 1710 may be performed according to methods as described herein. In some examples, aspects of the operations of 1710 may be performed as described with reference to Figures 9 to 12 The described RACH request instance components are performed.

[0226] At 1715, the base station may receive a second instance of a random access request message for a random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity. The operations of 1715 may be performed according to methods as described herein. In some examples, aspects of the operations of 1715 may be performed as described with reference to Figures 9 to 12 The described additional RACH request example components are performed.

[0227] At 1720, the base station may send a RAR of a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving a first instance and a second instance of a random access request message during two or more opportunities in the opportunity set. The operations of 1720 may be performed according to methods as described herein. In some examples, aspects of the operations of 1720 may be performed as described with reference to Figures 9 to 12 The described RAR component is used to perform.

[0228] Fig.18 1 is a flow chart of a method 1800 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1800 may be implemented by a base station 105 or a component thereof as described herein. For example, the operations of the method 1800 may be implemented by a base station 105 or a component thereof as described herein. Figures 9 to 12 The base station may be executed by the base station communication manager described in the foregoing. In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0229] At 1805, the base station may send configuration information to the UE for the UE to perform a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1805 may be performed according to methods as described herein. In some examples, aspects of the operations of 1805 may be performed as described with reference to Figures 9 to 12 The RACH configuration indicator described above is used to perform the above operation.

[0230] At 1810, the base station may determine a number of opportunities for the UE to send a random access request message, wherein the number of opportunities is based on a bandwidth for performing a random access procedure, a frequency range for a random access procedure, a frequency band for a random access procedure, or a combination thereof. The operations of 1810 may be performed according to methods as described herein. In some examples, aspects of the operations of 1810 may be performed as described with reference to Figures 9 to 12 The described RACH request opportunity number component is performed.

[0231] At 1815, the base station may send an indication of the number of opportunities to the UE in a configuration message. The operations of 1815 may be performed according to methods as described herein. In some examples, aspects of the operations of 1815 may be performed as described with reference to Figures 9 to 12 The described RACH request opportunity number component is performed.

[0232] At 1820, the base station may receive a first instance of a random access request message for a random access procedure from the UE during a first opportunity in the set of opportunities. The operations of 1820 may be performed according to methods as described herein. In some examples, aspects of the operations of 1820 may be performed as described with reference to Figures 9 to 12 The described RACH request instance components are performed.

[0233] At 1825, the base station may receive a second instance of a random access request message for a random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity. The operations of 1825 may be performed according to methods as described herein. In some examples, aspects of the operations of 1825 may be performed as described with reference to Figures 9 to 12 The described additional RACH request example components are performed.

[0234] At 1830, the base station may send a RAR of a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving a first instance and a second instance of a random access request message during two or more opportunities in the opportunity set. The operations of 1830 may be performed according to methods as described herein. In some examples, aspects of the operations of 1830 may be performed as described with reference to Figures 9 to 12 The described RAR component is used to perform.

[0235] Fig.19 1 is a flow chart of a method 1900 for supporting repeated random access transmissions according to various aspects of the present disclosure. The operations of the method 1900 may be implemented by a base station 105 or a component thereof as described herein. For example, the operations of the method 1900 may be implemented by a base station 105 or a component thereof as described herein. Figures 9 to 12 The base station may be executed by the base station communication manager described in the foregoing. In some examples, the base station may execute an instruction set to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the functions described below.

[0236] At 1905, the base station may send configuration information to the UE for the UE to perform a random access procedure with the base station within a set of opportunities associated with the configuration information. The operations of 1905 may be performed according to methods as described herein. In some examples, aspects of the operations of 1905 may be performed as described with reference to Figures 9 to 12 The RACH configuration indicator described above is used to perform the above operation.

[0237] At 1910, the base station may receive a first instance of a random access request message for a random access procedure from a UE during a first opportunity in a set of opportunities. The operations of 1910 may be performed according to methods as described herein. In some examples, aspects of the operations of 1910 may be performed as described with reference to Figures 9 to 12 The described RACH request instance components are performed.

[0238] At 1915, the base station may receive a second instance of a random access request message for a random access procedure from the UE during a second opportunity in the set of opportunities, the second opportunity occurring after the first opportunity. The operations of 1915 may be performed according to methods as described herein. In some examples, aspects of the operations of 1915 may be performed as described with reference to Figures 9 to 12 The described additional RACH request example components are performed.

[0239] At 1920, the base station may send a RAR of a random access procedure to the UE during a time window configured for transmitting the RAR, the RAR being sent based on receiving a first instance and a second instance of a random access request message during two or more opportunities in the opportunity set. The operations of 1920 may be performed according to methods as described herein. In some examples, aspects of the operations of 1920 may be performed as described with reference to Figures 9 to 12 The described RAR component is used to perform.

[0240] At 1925, the base station may determine that the UE is to send a random access request message within two or more opportunities in the opportunity set, wherein the first instance and the second instance of the random access request message are received based on the determination that the UE is to send a random access request message within two or more opportunities in the opportunity set. The operations of 1925 may be performed according to the methods described herein. In some examples, aspects of the operations of 1925 may be performed as described with reference to Figures 9 to 12 The described additional RACH request example components are performed.

[0241] The following provides an overview of various aspects of the present disclosure:

[0242] Aspect 1: A method for wireless communication at a UE, comprising: receiving configuration information from a base station for performing a random access procedure with the base station within multiple occasions associated with the configuration information; determining to send a random access request message for the random access procedure during two or more occasions among the multiple occasions based at least in part on a condition of a communication link between the UE and the base station; and sending a first instance of the random access request message during a first opportunity among the multiple occasions and sending a second instance of the random access request message during a second opportunity among the multiple occasions based at least in part on determining to send the random access request message during two or more occasions among the multiple occasions.

[0243] Aspect 2: The method according to Aspect 1 also includes: receiving information from a base station indicating a random access preamble code subset associated with sending a random access request message within two or more occasions among multiple occasions, the random access preamble code subset being indicated from a set of random access preamble codes that can be used for the random access process, wherein determining to send a random access request message during two or more occasions is at least partially based on the received information.

[0244] Aspect 3: The method according to aspect 2 also includes: selecting a random access preamble from a subset of random access preambles, wherein sending the first instance and the second instance of the random access request message during the first opportunity and the second opportunity includes sending the random access preamble.

[0245] Aspect 4: The method according to aspect 3, wherein a different cyclic shift is applied to the random access preamble for each instance of sending a random access request message.

[0246] Aspect 5: The method according to Aspect 2 also includes: selecting a first random access preamble code for a first time from a random access preamble code subset, wherein a first instance of sending a random access request message during the first time includes sending the first random access preamble code; selecting a second random access preamble code for a second time from the random access preamble code subset, wherein a second instance of sending a random access request message during the second time includes sending the second random access preamble code.

[0247] Aspect 6: The method according to any of Aspects 1 to 5 further includes: using configuration information, performing power measurements associated with the communication link; and determining that the power measurement satisfies a threshold, wherein determining that a random access request message is sent during two or more occasions is at least partially based on the power measurement satisfying the threshold.

[0248] Aspect 7: The method according to aspect 6, wherein the power measurement includes reference signal received power measurement, received signal strength indication measurement, or a combination thereof.

[0249] Aspect 8: The method according to any of aspects 1 to 7 further includes: identifying an exposure condition of the UE, wherein determining to send the random access request message during two or more opportunities is based at least in part on the exposure condition of the UE.

[0250] Aspect 9: The method according to any aspect of Aspects 1 to 8 further includes: receiving information from a base station, the information indicating a first length of a time window associated with sending a random access request message within two or more occasions among a plurality of occasions, and a second length of a time window associated with sending a random access request message within a single occasion among a plurality of occasions, the time window being used to transmit a random access response of a random access process to a UE, and the first length being shorter than the second length.

[0251] Aspect 10: A method according to Aspect 9, wherein a first instance of the random access request message is sent before a first time window having a first length, and a second instance of the random access request message is sent after a first time window associated with the first instance expires according to the first length.

[0252] Aspect 11: The method according to any of Aspects 9 to 10 further includes: monitoring a random access response of the random access process after the last instance of sending a random access request message, wherein the random access response is monitored during a time window according to a first length.

[0253] Aspect 12: The method according to any of aspects 9 to 11 further includes: determining the first length of the time window and the second length of the time window based at least in part on a single bit field in the information, a time window length table, or a combination thereof.

[0254] Aspect 13: A method according to any of Aspects 9 to 12, wherein the first length of the time window is based at least in part on the second length of the time window, the frequency range used for the random access procedure, the frequency band used for the random access procedure, or a combination thereof.

[0255] Aspect 14: The method according to any aspect of Aspects 1 to 13 further includes: determining the number of opportunities for sending a random access request message based at least in part on configuration information, wherein determining to send a random access request message during two or more opportunities is based at least in part on determining the number of opportunities.

[0256] Aspect 15: A method according to Aspect 14, wherein the number of opportunities for sending a random access request message is at least partially based on a bandwidth used to perform a random access procedure, a frequency range used for a random access procedure, a spectrum band used for a random access procedure, or a combination thereof.

[0257] Aspect 16: The method according to any of aspects 1 to 15, wherein the configuration information is received via a synchronization signal block, a system information block, system information, or a combination thereof.

[0258] Aspect 17: A method according to any of Aspects 1 to 16, wherein a plurality of opportunities occur between receiving a first synchronization signal block carrying configuration information and receiving a second synchronization signal block carrying additional configuration information.

[0259] Aspect 18. A method for wireless communication at a base station, comprising: sending configuration information to a UE so that the UE can perform a random access process with the base station within multiple opportunities associated with the configuration information; during a first opportunity among the multiple opportunities, receiving a first instance of a random access request message for the random access process from the UE; during a second opportunity among the multiple opportunities, receiving a second instance of the random access request message for the random access process from the UE, the second opportunity occurring after the first opportunity; during a time window configured for transmitting a random access response for the random access process, sending a random access response to the UE, the random access response being sent at least in part based on receiving the first instance and the second instance of the random access request message during two or more opportunities among the multiple opportunities.

[0260] Aspect 19: The method according to Aspect 18 also includes: sending information to the UE indicating a random access preamble code subset associated with the UE sending a random access request message within two or more occasions among multiple occasions, and the random access preamble code subset is indicated from a set of random access preamble codes that can be used for the random access process.

[0261] Aspect 20: The method according to aspect 19, wherein the first instance and the second instance of the random access request message are received together with the same random access preamble or different random access preambles.

[0262] Aspect 21: A method according to any of Aspects 19 to 20, wherein a first instance of the random access request message is received together with a random access preamble code to which a first cyclic shift is applied, and a second instance of the random access request message is received together with a random access preamble code to which a second cyclic shift is applied.

[0263] Aspect 22: The method according to any aspect of Aspects 18 to 21 further includes: sending information indicating the following to the UE: a first length of a time window associated with the UE sending a random access request message at two or more occasions among multiple occasions, and a second length of a time window associated with the UE sending a random access request message at a single occasion among the multiple occasions, the first length being shorter than the second length.

[0264] Aspect 23: The method according to Aspect 22 also includes: determining the first length of the time window based at least in part on the second length of the time window, the frequency range used for the random access process, the frequency band used for the random access process, or a combination thereof.

[0265] Aspect 24: A method according to any of Aspects 22 to 23, wherein the first length of the time window and the second length of the time window are indicated at least in part based on a single bit field in signaling, a time window length table, or a combination thereof.

[0266] Aspect 25: The method according to any of aspects 22 to 24, wherein the second instance of the random access request message is received after the first instance of the random access request message according to the first length.

[0267] Aspect 26: The method according to any aspect of Aspects 18 to 25 also includes: determining the number of opportunities for the UE to send a random access request message, wherein the number of opportunities is at least partially based on the bandwidth used to perform the random access process, the frequency range used for the random access process, the frequency band used for the random access process, or a combination thereof; and sending an indication of the number of opportunities to the UE in the configuration information.

[0268] Aspect 27: The method according to any aspect of Aspects 18 to 26 further includes: determining that the UE is to send a random access request message within two or more occasions among multiple occasions, wherein the first instance and the second instance of the random access request message are received at least in part based on determining that the UE is to send a random access request message within two or more occasions among the multiple occasions.

[0269] Aspect 28: The method according to aspect 27, wherein determining that the UE will send a random access request message within two or more of the multiple occasions is based at least in part on power measurements, exposure conditions of the UE, or a combination thereof.

[0270] Aspect 29: The method according to any of Aspects 18 to 28 further includes: selecting a first beam to receive a first instance of a random access request message; and selecting a second beam to receive a second instance of the random access request message, the second beam being different from the first beam.

[0271] Aspect 30: The method according to aspect 29, wherein the first beam and the second beam are different based at least in part on a beam refinement process.

[0272] Aspect 31: The method according to any of aspects 18 to 30, wherein the configuration information is sent via a synchronization signal block, a system information block, system information, or a combination thereof.

[0273] Aspect 32: A method according to any of Aspects 18 to 31, wherein a plurality of opportunities occur between sending a first synchronization signal block carrying configuration information and sending a second synchronization signal block carrying additional configuration information.

[0274] Aspect 33: An apparatus for wireless communication at a UE, comprising a processor, a memory coupled to the processor, and instructions, the instructions being stored in the memory and executable by the processor to cause the apparatus to perform the method according to any of aspects 1 to 17.

[0275] Aspect 34: An apparatus for wireless communication at a UE, comprising at least one unit for performing the method according to any of aspects 1 to 17.

[0276] Aspect 35: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method according to any of aspects 1 to 17.

[0277] Aspect 36: An apparatus for wireless communication at a base station, comprising a processor, a memory coupled to the processor, and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method according to any of aspects 18 to 32.

[0278] Aspect 37: An apparatus for wireless communication at a base station, comprising at least one unit for performing the method according to any of aspects 18 to 32.

[0279] Aspect 38: A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to perform the method according to any of aspects 18 to 32.

[0280] It should be noted that the methods described herein describe possible implementations, and the operations and steps may be rearranged or otherwise modified, and other implementations are possible. In addition, aspects of two or more of the methods may be combined.

[0281] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems are described for example purposes, and LTE, LTE-A, LTE-A Pro, or NR terminology is used in much of the description, the techniques described herein may be applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0282] The information and signals described herein may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout this specification may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0283] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may also be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other such structure).

[0284] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features used to implement the functions may be physically located at various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0285] Computer-readable medium includes both non-transitory computer storage medium and communication medium, and communication medium includes any medium that promotes computer program to be transmitted from one place to another place.Non-transitory storage medium can be any available medium that general or special-purpose computer can access.By way of example and not limitation, non-transitory computer-readable medium can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage device, or can be used for carrying or storing the program code unit with instruction or data structure form expectation and can be accessed by general or special-purpose computer or general or special-purpose processor any other non-transitory medium.In addition, any connection is appropriately referred to as computer-readable medium.For example, if software is to use coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, from website, server or other remote source transmission, then described coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are included in the definition of computer-readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs use lasers to reproduce data optically. Combinations of the above are also included within the scope of computer-readable media.

[0286] As used herein (including in the claims), "or" as used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can be based on condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0287] In the drawings, similar components or features have the same reference numeral. In addition, individual components of the same type may be distinguished by following the reference numeral with a dash and a second reference numeral that distinguishes the similar components. If only the first reference numeral is used in the specification, the description is applicable to any of the similar components having the same first reference numeral, regardless of the second or other subsequent reference numerals.

[0288] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations, but do not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," and is not "more preferred" or "more advantageous" than other examples. The specific embodiments include specific details to provide a thorough understanding of the described techniques. However, these techniques may be implemented without these specific details. In some instances, in order to avoid obscuring the concepts of the described examples, well-known structures and devices are shown in block diagram form.

[0289] The description herein is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the examples and designs described herein, but to be given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment (UE), comprising: receiving configuration information from a base station for performing a random access procedure with the base station within a plurality of occasions associated with the configuration information, the configuration information indicating a first length of a time window and a second length of the time window, wherein the time window is used to transmit a random access response associated with sending a random access request message for the random access procedure, and wherein the first length is shorter than the second length; determining, based at least in part on a condition of a communication link between the UE and the base station, two or more instances of sending the random access request message of the random access procedure during two or more of the plurality of opportunities; and and performing the random access procedure, wherein performing the random access procedure comprises: sending the two or more instances of the random access request message during the two or more opportunities of the plurality of opportunities based at least in part on the determining and according to the configuration information indicating the first length and the second length, sending a first instance of the random access request message during a first opportunity of the plurality of opportunities and sending a second instance of the random access request message during a second opportunity of the plurality of opportunities.

2. The method according to claim 1, further comprising: receiving, from the base station, information indicating a subset of random access preambles, the subset of random access preambles being indicated from a set of random access preambles that can be used for the random access procedure, wherein determining to send the random access request message during the two or more opportunities is based at least in part on receiving the information.

3. The method according to claim 2, further comprising: A random access preamble is selected from the random access preamble subset, wherein performing the random access procedure further comprises sending the random access preamble.

4. The method according to claim 3, wherein: For each instance of the random access request message sent, a different cyclic shift is applied to the random access preamble.

5. The method according to claim 2, further comprising: selecting a first random access preamble from the subset of random access preambles for the first opportunity, wherein sending the first instance of the random access request message during the first opportunity comprises sending the first random access preamble; and A second random access preamble is selected for the second occasion from the subset of random access preambles, wherein sending the second instance of the random access request message during the second occasion comprises sending the second random access preamble.

6. The method according to claim 1, further comprising: using the configuration information, performing power measurements associated with the communication link; as well as Determining that the power measurement satisfies a threshold, wherein the determining to send the random access request message during the two or more opportunities is based at least in part on the power measurement satisfying the threshold.

7. The method according to claim 6, wherein: The power measurement includes a reference signal received power measurement, a received signal strength indication measurement, or a combination thereof.

8. The method according to claim 1, further comprising: An exposure condition of the UE is identified, wherein determining to send the random access request message during the two or more opportunities is based at least in part on the exposure condition of the UE.

9. The method according to claim 1 in, The first length of the time window for transmitting the random access response is associated with sending the random access request message within the two or more opportunities among the multiple opportunities, and the second length of the time window for transmitting the random access response is associated with sending the random access request message within a single opportunity among the multiple opportunities.

10. The method according to claim 9, wherein: The first instance of the random access request message is sent before a first time window having the first length, and the second instance of the random access request message is sent after the first time window associated with the first instance expires according to the first length.

11. The method according to claim 9, further comprising: After sending a last instance of the random access request message, monitoring the random access procedure for the random access response, wherein the random access response is monitored during the time window according to the first length.

12. The method according to claim 9, further comprising: The first length of the time window and the second length of the time window are determined based at least in part on a single bit field in the configuration information, a time window length table, or a combination thereof.

13. The method according to claim 9, wherein: The first length of the time window is based at least in part on a frequency range used for the random access procedure, a frequency band used for the random access procedure, or a combination thereof.

14. The method according to claim 1, further comprising: A number of the plurality of opportunities for sending the random access request message is determined based at least in part on the configuration information, wherein the determining to send the random access request message during the two or more opportunities is based at least in part on determining the number of opportunities.

15. The method according to claim 14, wherein: The number of opportunities for sending the random access request message is based at least in part on a bandwidth used to perform the random access procedure, a frequency range used for the random access procedure, a spectrum band used for the random access procedure, or a combination thereof.

16. The method according to claim 1, wherein: The configuration information is received via a synchronization signal block, a system information block, system information, or a combination thereof.

17. The method according to claim 1, wherein: The multiple opportunities occur between receiving a first synchronization signal block carrying the configuration information and receiving a second synchronization signal block carrying additional configuration information.

18. A method for wireless communication at a base station, comprising: Sending configuration information to a user equipment (UE) for the UE to perform a random access procedure with the base station within a plurality of occasions associated with the configuration information, the configuration information indicating a first length of a time window and a second length of the time window, wherein the time window is used to transmit a random access response associated with receiving a random access request message for the random access procedure, and wherein the first length is shorter than the second length; receiving, during a first opportunity among the plurality of opportunities and in accordance with the configuration information indicating the first length and the second length, a first instance of the random access request message for the random access procedure from the UE; receiving, during a second opportunity among the plurality of opportunities and in accordance with the configuration information indicating the first length and the second length, a second instance of the random access request message for the random access procedure from the UE, the second opportunity occurring after the first opportunity; and During the time window configured for transmitting the random access response of the random access procedure, the random access response is sent to the UE, the random access response being sent based at least in part on receiving the first and second instances of the random access request message during two or more of the multiple occasions.

19. The method according to claim 18, further comprising: and sending information indicating a subset of random access preambles to the UE, the subset of random access preambles being indicated from a set of random access preambles that can be used for the random access procedure, wherein the first instance and the second instance of receiving the random access request message during the two or more occasions are based at least in part on sending the configuration information.

20. The method according to claim 19, wherein: The first instance and the second instance of the random access request message are received with the same random access preamble or different random access preambles.

21. The method according to claim 19, wherein: The first instance of the random access request message is received with a random access preamble to which a first cyclic shift is applied, and the second instance of the random access request message is received with a random access preamble to which a second cyclic shift is applied.

22. The method according to claim 18: in, The first length of the time window for sending the random access response is associated with transmission of the random access request message within the two or more opportunities among the multiple opportunities, and the second length of the time window for sending the random access response is associated with transmission of the random access request message within a single opportunity among the multiple opportunities, and the first length is shorter than the second length.

23. The method according to claim 22, further comprising: The first length of the time window is determined based at least in part on a frequency range used for the random access procedure, a frequency band used for the random access procedure, or a combination thereof.

24. The method according to claim 22, wherein: The first length of the time window and the second length of the time window are indicated based at least in part on a single bit field in the configuration information, a time window length table, or a combination thereof.

25. The method according to claim 22, wherein: The second instance of the random access request message is received after the first instance of the random access request message according to the first length.

26. The method of claim 18, further comprising: determining a number of opportunities for the UE to send the random access request message, wherein the number of opportunities is based at least in part on a bandwidth used to perform the random access procedure, a frequency range used for the random access procedure, a frequency band used for the random access procedure, or a combination thereof; and An indication of the number of opportunities is sent to the UE in the configuration information.

27. The method of claim 18, further comprising: and determining that the UE is to send the random access request message within the two or more opportunities of the plurality of opportunities, wherein the first instance and the second instance of the random access request message are received based at least in part on the determination.

28. The method of claim 18, further comprising: selecting a first beam to receive the first instance of the random access request message; as well as A second beam is selected to receive the second instance of the random access request message, the second beam being different from the first beam.

29. An apparatus for wireless communication at a user equipment (UE), comprising: means for receiving configuration information from a base station for performing a random access procedure with the base station within a plurality of occasions associated with the configuration information, the configuration information indicating a first length of a time window and a second length of the time window, wherein the time window is used to transmit a random access response associated with sending a random access request message for the random access procedure, and wherein the first length is based on the second length and the first length is shorter than the second length; means for determining, based at least in part on a condition of a communication link between the UE and the base station, to send two or more instances of the random access request message of the random access procedure during two or more of the plurality of opportunities; and Means for performing the random access procedure, wherein performing the random access procedure comprises: sending the two or more instances of the random access request message during the two or more opportunities of the plurality of opportunities based at least in part on the determining and in accordance with the configuration information indicating the first length and the second length, sending a first instance of the random access request message during a first opportunity of the plurality of opportunities and sending a second instance of the random access request message during a second opportunity of the plurality of opportunities.

30. An apparatus for wireless communication at a base station, comprising: means for sending configuration information to a user equipment (UE) for the UE to perform a random access procedure with the base station within a plurality of occasions associated with the configuration information, the configuration information indicating a first length of a time window and a second length of the time window, wherein the time window is used to transmit a random access response associated with receipt of a random access request message for the random access procedure, and wherein the first length is shorter than the second length; means for receiving, during a first opportunity among the plurality of opportunities and in accordance with the configuration information indicating the first length and the second length, a first instance of the random access request message for the random access procedure from the UE; means for receiving, from the UE, a second instance of the random access request message for the random access procedure during a second opportunity among the plurality of opportunities and in accordance with the configuration information indicating the first length and the second length, the second opportunity occurring after the first opportunity; and and means for sending, to the UE, during the time window configured for transmitting the random access response of the random access procedure, the random access response being sent based at least in part on receiving the first and second instances of the random access request message during two or more of the plurality of occasions.

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