Narrowband random access preambles for non-terrestrial network communications

Methods, systems, and devices for wireless communications are described in which random access preambles may be designed to provide for relatively low inter-carrier interference (ICI) of adjacent available frequency resources in a non-terrestrial network (NTN). Random access preambles for NTN random access requests may be selected from a first set of random access preambles that are different from a second set of random access preambles for terrestrial random access requests. The first set of random access preambles may be a subset of the second set of random access preambles. The first set of random access preambles may be provided for contention-based random access (CBRA) and contention-free random access (CFRA) preambles may be configured by a base station from random access preambles that correspond to or are different from the second set of random access preambles.

FIELD OF TECHNOLOGY

The following relates generally to wireless communications and more specifically to narrowband random access preambles for non-terrestrial network communications.

BACKGROUND

In some cases, there may be a large distance between a UE and a serving node of the UE, such as when one or more of a gateway, base station, or the UE are at a high altitude relative to one another (e.g., in a non-terrestrial network (NTN) or system with high altitude platform stations (HAPSs)). Because of the distance between wireless nodes in such cases, signal strength for communications may be relatively low, and there may be a relatively long round-trip delay or propagation delay in message transmissions (e.g., relative to terrestrial networks). Further, communications in such situations may experience relatively large amounts of Doppler shift due to relatively fast movement of nodes relative to one another. Efficient techniques for managing communications to enhance efficiency and reliability may thus be desirable for such systems.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support narrowband random access preambles for non-terrestrial networks. In accordance with various aspects, random access preambles may be designed to provide for relatively low inter-carrier interference (ICI) for random access preambles that may be transmitted using adjacent available frequency resources in a non-terrestrial network (NTN). In some cases, random access preambles for NTN random access requests may be selected from a first set of random access preambles that may have parameters that are different from a second ret of random access preambles for terrestrial network random access messages. In some cases, the first set of random access preambles may facilitate uplink synchronization in the presence of larger frequency shifts in random access messages than the second set of random access preambles. In some cases, the first set of random access preambles may be a subset of the second set of random access preambles. For example, in some cases, an initial subcarrier for a random access preamble of the first set of random access preambles may be selected from a subset of a set of available initial subcarriers, where the second set of random access preambles may include all of the set of available initial subcarriers. In some cases, a subset of the first set of random access preambles may be provided for contention-based random access (CBRA) in NTN, and contention-free random access (CFRA) preambles may be configured by a base station from random access preambles that correspond to or are different from a subset of the second set of random access preambles.

A method of wireless communication at a UE is described. The method may include receiving, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, selecting, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network, and transmitting the random access message to the base station via the satellite link using the selected narrowband random access parameters.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network, and transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, selecting, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network, and transmitting the random access message to the base station via the satellite link using the selected narrowband random access parameters.

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, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network, and transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of narrowband random access parameters include a first set of starting subcarriers allocated for contention-based random access preambles and may be different from a second set of starting subcarriers allocated for contention-based random access preambles in the second set of narrowband random access parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, adjacent starting subcarriers of the first set of starting subcarriers may have a first frequency spacing that is larger than a second frequency spacing between adjacent starting subcarriers of the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers allocated for contention-based random access preambles may have fewer available starting subcarriers per unit of frequency than the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers may have a different range of starting subcarriers within a total number of available starting subcarriers for contention-based random access and contention-free random access than that of the second set of starting subcarriers.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers corresponds to a subset of the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers may be selected from the second set of starting subcarriers based on one or more of a starting subcarrier index value or a pattern of starting subcarriers from the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the pattern of starting subcarriers includes one out of every m consecutive starting subcarriers from the second set of starting subcarriers, where m is an integer.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of a total number of available starting subcarriers allocated for contention-based and contention-free random access preambles in the second set of narrowband random access parameters, where the first set of starting subcarriers is determined at least in part by a pattern of starting subcarriers from the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the pattern of starting subcarriers includes one out of every m consecutive starting subcarriers from the total number of available starting subcarriers in the second set of narrowband random access parameters, where m is an integer.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of narrowband random access parameters include a first set of random access preambles for contention-based random access that have one or more different characteristics than a second set of random access preambles of the second set of narrowband random access parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of random access preambles may have one or more of a different intra-preamble repetition unit (PRU) frequency hopping pattern, a different inter-PRU frequency hopping pattern, a different subcarrier spacing, a different number of subcarriers spanned in frequency, or any combinations thereof, relative to the second set of random access preambles. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, at least one intra-PRU hopping pattern provides that two random access preambles that are adjacent in frequency in a first portion of the PRU are non-adjacent in frequency in a second part of the PRU.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of random access preambles are configured from a first candidate set of random access preambles and the second set of random access preambles are configured from a second candidate set of random access preambles, where the first candidate set of preambles is a subset of the second candidate set of random access preambles. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, one or more preamble formats, preamble subcarrier spacings, or any combinations thereof of the second candidate set of random access preambles are precluded from the first candidate set of random access preambles.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the receiving the configuration information further may include operations, features, means, or instructions for receiving an indication of a first subset of the first set of narrowband random access parameters that provide resources corresponding to the first subset and a second subset of the first set of narrowband random access parameters that provide resources corresponding to the second subset, where the resources corresponding to the first subset have one or more parameters that are different than corresponding parameters of the second subset resources. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the resources corresponding to the first subset or the second subset are any one of contention-based random access resources or contention-free random access resources.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first subset of narrowband random access parameters use random access parameters that are not different from those of terrestrial random access messages and the second subset of narrowband random access parameters use random access parameters specific to non-terrestrial random access messages. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the random access parameters include one or more of a set of starting subcarrier indices, a frequency hopping pattern for random access preambles, a subcarrier spacing, a number of subcarriers spanned in frequency, or any combinations thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the resources corresponding to the first subset and the resources corresponding to the second subset are located in a same set of frequency resources and in different time resources, in different sets of frequency resources and a same set of time resources, in different frequency and time resources, or interlaced with each other within the same set of time and frequency resources. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a periodicity of the resources corresponding to the first subset are different from a periodicity of the resources corresponding to the second subset.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitting the random access message further includes transmitting one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access preamble message transmissions. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for periodic contention-free random access resources is received from the base station in radio resource control signaling. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for periodic contention-free random access resources is activated based on activation signaling received in one or more of a medium access control (MAC) control element or a downlink control information communication from the base station. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the activation signaling includes information for adjustment of one or more parameters associated with the one or more further random access messages.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the base station, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the time or frequency correction command may be provided in the physical layer downlink control information when the indicated correction value is less than a threshold value, and where the time or frequency correction command is provided in a medium access control (MAC) control element when the indicated correction value meets or exceeds the threshold value.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of narrowband random access parameters supports different random access resource configurations associated with one or more repetitions of a preamble repetition unit (PRU) than the second set of narrowband random access parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a maximum number of preamble repetitions supported by the first set of narrowband random access parameters is less than the maximum number of repetitions supported by the second set of narrowband random access parameters for at least a subset of random access preamble configurations.

A method of wireless communication at a base station is described. The method may include transmitting, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, detecting one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters, and transmitting a random access response to the UE via the satellite link responsive to the detecting.

An apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters, and transmit a random access response to the UE via the satellite link responsive to the detecting.

Another apparatus for wireless communication at a base station is described. The apparatus may include means for transmitting, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, detecting one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters, and transmitting a random access response to the UE via the satellite link responsive to the detecting.

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 transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters, and transmit a random access response to the UE via the satellite link responsive to the detecting.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of narrowband random access parameters include a first set of starting subcarriers allocated for contention-based random access preambles and are different from a second set of starting subcarriers allocated for contention-based random access preambles in the second set of narrowband random access parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, adjacent starting subcarriers of the first set of starting subcarriers have a first frequency spacing that is larger than a second frequency spacing between adjacent starting subcarriers of the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers allocated for contention-based random access preambles have fewer available starting subcarriers per unit of frequency than the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers have a different range of starting subcarriers within a total number of available starting subcarriers for contention-based random access and contention-free random access than that of the second set of starting subcarriers.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers corresponds to a subset of the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers may be selected from the second set of starting subcarriers based on one or more of a starting subcarrier index value or a pattern of starting subcarriers from the second set of starting subcarriers.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of a total number of available starting subcarriers allocated for contention-based and contention-free random access preambles in the second set of narrowband random access parameters, where the first set of starting subcarriers may be determined at least in part by a pattern of starting subcarriers from the second set of starting subcarriers. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of narrowband random access parameters include a first set of random access preambles for contention-based random access that have one or more different characteristics than a second set of random access preambles of the second set of narrowband random access parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of random access preambles have one or more of a different intra-preamble repetition unit (PRU) frequency hopping pattern, a different inter-PRU frequency hopping pattern, a different subcarrier spacing, a different number of subcarriers spanned in frequency, or any combinations thereof, relative to the second set of random access preambles. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, at least one intra-PRU hopping pattern provides that two random access preambles that are adjacent in frequency in a first portion of the PRU are non-adjacent in frequency in a second part of the PRU.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of random access preambles are configured from a first candidate set of random access preambles and the second set of random access preambles are configured from a second candidate set of random access preambles, where the first candidate set of preambles is a subset of the second candidate set of random access preambles. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, one or more preamble formats, preamble subcarrier spacings, or any combinations thereof of the second candidate set of random access preambles are precluded from the first candidate set of random access preambles.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the transmitting the configuration information further may include operations, features, means, or instructions for transmitting an indication of a first subset of the first set of narrowband random access parameters that provide resources corresponding to the first subset and a second subset of the first set of narrowband random access parameters that provide resources corresponding to the second subset, where the resources corresponding to the first subset have one or more parameters that are different than corresponding parameters of the second subset resources. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first subset of narrowband random access parameters use random access parameters that are not different from those of terrestrial random access messages and the second subset of narrowband random access parameters use random access parameters specific to non-terrestrial random access messages.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the random access parameters include one or more of a set of starting subcarrier indices, a frequency hopping pattern for random access preambles, a subcarrier spacing, a number of subcarriers spanned in frequency, or any combinations thereof. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the resources corresponding to the first subset and the resources corresponding to the second subset are located in a same set of frequency resources and in different time resources, in different sets of frequency resources and a same set of time resources, in different frequency and time resources, or interlaced with each other within the same set of time and frequency resources.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the receiving the random access message further includes receiving one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access message transmissions. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the configuration for periodic contention-free random access resources is transmitted to the UE in radio resource control signaling and activated based on activation signaling transmitted in one or more of a medium access control (MAC) control element or a downlink control information communication from the base station. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the activation signaling includes information for adjustment of one or more parameters associated with the one or more further random access messages.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the UE, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of narrowband random access parameters supports different random access resource configurations associated with one or more repetitions of a preamble repetition unit (PRU) than the second set of narrowband random access parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a maximum number of preamble repetitions supported by the first set of narrowband random access parameters is less than the maximum number of repetitions supported by the second set of narrowband random access parameters for at least a subset of random access preamble configurations.

DETAILED DESCRIPTION

Non-terrestrial networks (sometimes referred to as NTNs) may provide coverage by using high-altitude vehicles between user terminals and gateways or base stations (e.g., next-generation NodeBs or giga-NodeBs (which may be referred to as a gNB, and also referred to as access stations or access gateways)). A gateway may, for example, transmit data to a satellite which may then be relayed to a user terminal, and vice-versa. A high-altitude vehicle itself may be a base station, in some examples. A user terminal may be any device capable of transmitting signals to a satellite. Examples of a user terminal may include a user equipment (UE), a relay equipment configured to relay a signal between a satellite and a user terminal, or a combination thereof. NTNs may involve the use of high altitude platform stations (HAPSs) and/or satellites to provide coverage for terrestrial base stations and UEs. The terms HAPS and satellite are used interchangeably herein to refer to a remote NTN device that may provide coverage to one or more other high altitude or terrestrial devices. Likewise, the terms gateway and base station are used interchangeably herein to refer to a network node that serves a UE and provides network access to the UE.

The gateway and the satellite may be thousands of kilometers apart and it may take some time for electromagnetic waves to propagate over the distance between the gateway and the satellite and between the satellite and the user terminal. Thus, the propagation delay for non-terrestrial networks may be many orders of magnitude larger than the propagation delay for terrestrial networks. As such, the round trip delay (sometimes referred to as an RTD) associated with a signal may also be orders of magnitude larger for non-terrestrial networks than for terrestrial networks. Further, due to the high mobility of high-altitude vehicles such as non-geostationary satellites, communications with some satellites may promote large and time-varying Doppler shifts.

In some systems, one or more UEs, satellites, and gateways may support narrowband communications (e.g., narrowband Internet-of-Things (NB-IoT) communications), in which devices may use a relatively narrow frequency bandwidth for communications. Uplink synchronization (in time and frequency) in NB-IoT communications, similarly as in other types of cellular communications systems, may be achieved by a UE transmitting a “random access preamble” over a narrowband physical random access channel (NPRACH) in the uplink. A base station that receives the random access preamble may then determine the time and frequency offset of the received signal from the UE with respect to the base-station's time and frequency references. In terrestrial systems, the UE is then provided with a timing advance (TA) command to compensate for the timing difference with respect to the base-station's reference. In some terrestrial systems, the residual frequency offset of such communications is relatively small, and as long as the base station is aware of the offset (e.g., a carrier frequency offset (CFO)), the base station does not need to send a frequency correction command to the UE. In NTNs, however, the frequency offset between the received signal from the UE and the base-station's reference may be relatively large, due to the multiple Doppler shift components that may be present in NTNs (e.g., due to a satellite's continuous state of motion in its orbit). In some cases such frequency shifts may be significant enough to create a loss of orthogonality across subcarriers across the transmissions received at the base station (i.e., inter-carrier interference (ICI) from multiple UEs having (potentially different) frequency offsets). Various aspects of the present disclosure provide techniques to allow efficient uplink communications for NB-IoT over NTNs, taking into account the potentially large frequency offset.

As described herein, UEs, gateways, and satellites may support random access techniques in which random access preambles may be designed to provide for relatively low ICI for adjacent random access frequency resources used in a NTN. As used herein, “adjacent” resources (e.g., adjacent random access preamble frequency resources) refer to valid resources that are directly prior to or subsequent to a particular resource (e.g., for a valid frequency resource n that is available for transmission of a random access preamble, adjacent random access resources would be valid frequency resources n−1 and n+1, where the n+1thor n−1thvalid resource may not be consecutive in frequency to the nthvalid resource). In some cases, random access preambles for NTN random access requests may be selected from a first set of random access preambles that may have parameters that are different from a second ret of random access preambles for terrestrial network random access messages. In some cases, the first set of random access preambles may provide for larger frequency shifts in random access messages than the second set of random access preambles for terrestrial random access requests. In some cases, the first set of random access preambles may correspond to a subset of the second set of random access preambles. For example, in some cases an initial subcarrier for a random access preamble of the first set of random access preambles may be selected from a subset of a set of available initial subcarriers, where the second set of random access preambles may include all of the set of available initial subcarriers. In some cases, an entire range of available initial subcarriers from the second set of random access preambles may be available for use in contention-based random access (CBRA) and contention-free random access (CFRA), where CBRA preambles may have a limited set of valid initial subcarriers within the range, and where CFRA preambles may be configured by a base station from random access preambles that correspond to or are different from the second set of random access preambles.

Particular aspects of the subject matter described herein may be implemented to realize one or more of the following potential advantages. The described techniques may support improvements in reliability for random access messages from a UE to a base station in communications using high-altitude vehicles and/or high velocity vehicles (e.g., satellites or other non-terrestrial-based equipment), user terminals, and gateways, in non-terrestrial networks, among other advantages. As such, supported techniques may include features for enhancing efficiency of non-terrestrial communications. The described techniques may also support reduced latency for random access procedures and, in some examples, may promote higher mobility support for user terminals in non-terrestrial networks compared to terrestrial networks, among other benefits.

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are also illustrated by resource diagrams and timing diagrams. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to narrowband random access preambles for non-terrestrial network communications.

The base stations105may communicate with the core network130, or with one another, or both. For example, the base stations105may interface with the core network130through one or more backhaul links (e.g., via an S1, N2, N3, or other interface). The base stations105may communicate with one another over the backhaul links (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations105), or indirectly (e.g., via core network130), or both. In some examples, the backhaul links may be or include one or more wireless links.

The wireless communications system100includes base stations105, UEs115, satellites120, and a core network130. In some examples, the wireless communications system100may be an LTE network, an LTE-A network, an LTE-A Pro network, or a NR network. In some cases, wireless communications system100may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Wireless communications system100may also include one or more satellites120. Satellites120(or other high altitude devices) may communicate with base stations105(also referred to as gateways in NTNs) and UEs115(or other high altitude or terrestrial communications devices). A satellite120may be any suitable type of communication satellite configured to relay communications between different end nodes in a wireless communication system. Satellites120may be examples of a space satellite, a balloon, a dirigible, an airplane, a drone, an unmanned aerial vehicle, and/or the like. In some examples, the satellites120may be in a geosynchronous or geostationary earth orbit, a low earth orbit or a medium earth orbit. A satellite120may be a multi-beam satellite configured to provide service for multiple service beam coverage areas in a predefined geographical service area. The satellite120may be any distance away from the surface of the earth.

In some cases, a cell may be provided or established by a satellite120as part of a non-terrestrial network. A satellite120may, in some cases, perform the functions of a base station105, act as a bent-pipe satellite, or may act as a regenerative satellite, or a combination thereof. In other cases, satellite120may be an example of a smart satellite, or a satellite with intelligence. For example, a smart satellite may be configured to perform more functions than a regenerative satellite (e.g., may be configured to perform particular algorithms beyond those used in regenerative satellites, to be reprogrammed, etc.). A bent-pipe transponder or satellite may be configured to receive signals from ground stations and transmit those signals to different ground stations. In some cases, a bent-pipe transponder or satellite may amplify signals or shift from uplink frequencies to downlink frequencies. A regenerative transponder or satellite may be configured to relay signals like the bent-pipe transponder or satellite, but may also use on-board processing to perform other functions. Examples of these other functions may include demodulating a received signal, decoding a received signal, re-encoding a signal to be transmitted, or modulating the signal to be transmitted, or a combination thereof. For example, a bent-pipe satellite (e.g., satellite120) may receive a signal from a base station105and may relay the signal to a UE115or base station105, or vice-versa.

UEs115may communicate with satellites120and/or base stations or gateways105using communications links125. In some cases, random access resources for UE115random access messages may be configured to provide sufficient frequency differences between adjacent frequency resources such that ICI of random access messages using the adjacent frequency resources, due to movement of the satellite120, is relatively low or eliminated for communications links125via a satellite120. In accordance with various techniques discussed herein, a UE115may select random access resources for random access messages via a NTN from a different set of available random access resources than used for terrestrial random access messages.

FIG.2illustrates an example of a wireless communications system200that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. In some examples, wireless communications system200may implement aspects of wireless communications system100. Wireless communications system200may include a gateway105-a(or base station), a UE115-a, and a satellite120-a, which may be examples of a base station105, UEs115, and satellites120as described with reference toFIG.1. The gateway105-amay serve a coverage area110-ain cases of a terrestrial network, and the satellite120-amay serve coverage area110-ain cases of an NTN.

In some examples, the satellite120-amay relay communications between the gateway105-aand the UE115-a. For example, the gateway105-amay communicate with the UE115-avia the satellite120-aor vice-versa. In some examples, for communications originating at the gateway105-aand going to the UE115-a, the gateway105-amay transmit an uplink transmission205-ato the satellite120-a, which may be referred to as a service link. The satellite120-amay relay the uplink transmission205-aas a downlink transmission205-bto the UE115-a, which may be referred to as a feeder link. In other examples, for communications originating at the UE115-aand going to the gateway105-a, the UE115-amay transmit an uplink transmission210-ato the satellite120-avia feeder link. The satellite120-amay relay the uplink transmission210-aas a downlink transmission210-bto gateway105-avia the service link.

The gateway105-aand the satellite120-amay be thousands of kilometers apart and the satellite120-amay be moving at a relatively high speed relative to the gateway105-a. Likewise, the gateway105-aand UE115-amay be thousands of kilometers apart and the satellite120-amay be moving at a relatively high speed relative to the UE115-a. Due to the high rates of speed of the satellite120-a, Doppler shifts of communications for non-terrestrial networks may be many orders of magnitude larger than the Doppler shifts for terrestrial networks. As a result, in cases where the UE115-auses NPRACH resources for random access message transmissions, such messages may be subject to Doppler shifts that, if terrestrial NPRACH configurations were implemented, may experience ICI in the event that another UE were to use an adjacent random access resource in frequency.

In some cases, NPRACH preambles for NTN random access requests may be configured to provide tolerances for additional frequency shifts relative to terrestrial NPRACH configurations. In some cases, NPRACH preambles may be selected by the UE115-afrom a first set of random access preambles for NTN communications that are different from a second set of random access preambles for terrestrial communications. In some cases, the first set of random access preambles may correspond to a subset of the second set of random access preambles. For example, in some cases an initial subcarrier for a random access preamble of the first set of random access preambles may be selected from a subset of a set of available initial subcarriers of the second set of random access preambles. In some cases, an entire range of available initial subcarriers from the second set of random access preambles may be available for use in contention-based random access (CBRA) and for use in contention-free random access (CFRA). In such cases, CBRA preambles may have a limited set of valid initial subcarriers within the range, and CFRA preambles for NTN communications may be configured by a base station from random access preambles that correspond to or are different from the second set of random access preambles. The base station in such cases may schedule different UEs115with CFRA preambles such that ICI from concurrent random access transmissions is low or not present.

FIG.3illustrates an example of a time-frequency mapping of narrowband random access preambles300that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. In some examples, time-frequency mapping of narrowband random access preambles300may implement aspects of wireless communications system100or200. In this example, a set of frequency resources in a set of random access resources may include a number of subcarriers that are available for a random access preamble transmission (e.g., a random access request that is transmitted from a UE to a base station), which may be referred to as a number of subcarriers spanned in frequency or NscRA.

A UE may transmit a random access preamble on the NPRACH channel for several different purposes, including for the purposes of enabling uplink time-frequency synchronization at the network, requesting channel access, and the like. Two types of NPRACH transmissions include UE-initiated communications (also termed contention-based), and network-initiated (also termed contention-free). A number of NPRACH preambles may be configured, which in this example includes a first preamble305, a second preamble310, a third preamble315, and a fourth preamble320. The time-frequency mapping of NPRACH preambles305through320may provide frequency hopping patterns that provide enhanced frequency diversity of a random access message transmission. Each NPRACH preamble305through320may include a symbol group325, which may include 3 or 5 (depending on preamble format) repetitions an OFDM symbol, along with a cyclic prefix (CP). A preamble repetition unit (PRU)330may include a configured number of symbol groups, such as 4 symbol groups in the example ofFIG.3. The symbol groups325may follow frequency hopping patterns, which may be further sub-divided into Intra-PRU hopping patterns (e.g., fixed patterns relative to the frequency location of the starting symbol group in a preamble repetition unit) and Inter-PRU hopping patterns (e.g., a pseudorandom determination of the frequency location of the starting symbol group in a PRU). With the above structure, an NPRACH preamble (out of all configured preambles) may be specified by the frequency location of the first symbol group in the first PRU, which may be determined according to:

As shown in the example ofFIG.3, the NPRACH preamble to be used is thus determined by the variable ninit, where, for UE-initiated preamble transmission (i.e., CBRA), the UE's MAC layer may randomly pick a value for ninitwithin the set {0, 1, . . . , Nsc_contNPRACH} out of the total possible range set {0, 1, . . . , NscNPRACH}. For network-initiated preamble transmission (i.e., CFRA), the network indicates a value of ninitfrom the set {0, 1, . . . , NscNPRACH}. The values of Nsc_contNPRACHand NscNPRACHare network configured and indicated by higher layers to a MAC layer of the UE.

In some cases, for terrestrial-based random access, from the above ranges of values for ninit, a priori, all values in the range set are permissible, and two UEs may end up randomly choosing ninitUE1and ninitUE2that are adjacent (e.g., differ by one starting subcarrier). As discussed above, in deployments that may experience relatively large Doppler shifts, random access messages transmitted in adjacent subcarriers may experience ICI, and thus in accordance with various aspects as discussed herein frequency resources for a random access message may be selected to avoid ICI. In some cases, for terrestrial NB-IoT random access, since the uplink frequency offset is in many cases not large enough to cause ICI at the base station between such “adjacent” preamble sequences, the selection of ninitfor CBRA may be from all available values of Nsc_contNPRACH. In other cases, such as discussed with reference to the examples ofFIGS.4through7, UEs may use random access preambles that provide for reduced ICI in high Doppler shift communications.

FIG.4illustrates an example of a narrowband random access resources400that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. In some examples, narrowband random access resources400may implement aspects of wireless communications system100or200. In this example, random access preamble configurations in NTN deployments may be different from those for terrestrial deployments.

In this example, a terrestrial configuration of preambles405may include a non-CBRA preamble subset410that may include values of ninitthat are reserved for CFRA and may be provided to a UE as part of a network-initiated random access message. The set of preambles405configured for terrestrial communication in this example also includes a CBRA preamble subset415, from which the UE can randomly select a value for ninit. As discussed above, when randomly selecting a value for ninit, the UE may select from the values {0, 1, . . . , Nsc_contNPRACH} of the CBRA preamble subset415, and in cases with network initiated random access the value for ninitmay be provided and from the total possible range set {0, 1, . . . , NscNPRACH}.

In some cases, different random access parameters may be used for NTN random access (e.g., for NB-IoT random access via a NTN), which provide for reduced ICI in the presence of relatively high Doppler frequency shifts for communications to or from a UE. In the example ofFIG.4, a candidate set of NTN preambles420may be configured that provide a limited number of valid ninitvalues for CBRA out of all ninitvalues in the range of the CBRA preamble subset430, and also provide a non-CBRA preamble subset425. In this candidate configuration, the CBRA preamble subset430may include additional possible ninitvalues compared to those provided for the terrestrial configuration of preambles405. Put another way, the maximum value of ninitfor the subset430may be larger than for subset415. In another example, a second candidate set of NTN preambles435may be provided that does not include subsets, where the ninitvalues may be selected from all available NscNPRACHvalues440. In such cases, relative to terrestrial configuration of preambles405, the differences may be in, for example, a range (maximum and minimum) of starting subcarriers for CBRA where, instead of the first Nsc_contNPRACHstarting subcarriers out of a possible NscNPRACHsubcarriers being allocated to CBRA, the CBRA preambles may be configured across the entire NscNPRACHsubcarriers, as in the second candidate set of NTN preambles435. In some cases, certain restrictions may be applied to the ninitvalues that may be selected, such as skipping certain starting subcarriers within a range to provide robustness from ICI across CBRA preambles. In some cases, the number of starting subcarriers allocated for CBRA may be configured to provide a reduced number of starting subcarriers for CBRA preambles per unit of frequency as compared to terrestrial configuration of preambles405. In other cases, the values and/or patterns of starting subcarriers within the range of possible values may be configured to provide robustness from ICI across CBRA preambles. For example, for CBRA, the UE may choose the value of ninitrandomly from the set

{0,2,4,…⁢,⌊Nsc_contN⁢P⁢R⁢A⁢C⁢H2⌋}
in the candidate NTN configuration of preambles420, which provides more protection from ICI across valid CBRA preambles. In examples where the second candidate set of NTN preambles435is used, the UE may choose the value of ninitrandomly from the set

{0,2,4,…⁢,⌊NscNPRACH2⌋}.
It is noted that the example patterns ofFIG.4are exemplary only, for purposes of illustration and discussion of the concept of skipping certain starting subcarriers and/or increasing the range of starting subcarriers to improve robustness to ICI of CBRA preambles. Patterns other than these examples may be used and are within the scope of the present disclosure.

In other cases, for at least for some time-frequency locations for NTN random access preamble transmissions, at least some preambles may differ from terrestrial preambles (e.g., the preambles in405) in at least one defining characteristic. For example, NTN preambles may have a different intra-PRU hopping pattern, a different inter-PRU hopping pattern, a different subcarrier Spacing (e.g. 7.5 kHz), a different frequency span (i.e., NscRA), or any combinations thereof, that may provide protection from ICI across CBRA preambles. For example, for at least a set of preamble sequences, the intra-PRU hopping pattern may be configured such that if two of these sequences are adjacent in frequency in a first part of a PRU, they are not adjacent in the second part of the PRU (while in the terrestrial preambles405, if any two sequences are adjacent in the first part of a PRU, they are also adjacent (by the same amount in frequency) in the second part of the PRU). In further cases, for at least for some time-frequency locations for random access preamble transmissions, certain preambles may be precluded in order to provide protection from ICI across CBRA preambles. For example, certain preamble formats (e.g. Preamble Format 2) may be precluded, or preambles with certain subcarrier spacings (e.g., 1.25 kHz) may be precluded. While the example ofFIG.4shows different sets of preambles that may be used for terrestrial and for NTN deployments, such sets of preambles may have other configurations and may be provided in periodic resources in which different resources may have different configurations for NTN random access messages.FIGS.5through7show some examples of such random access resource configurations for NTN.

While various of the described techniques provide for protection from ICI across CBRA preambles, CFRA preambles may be indicated by the network and may also be selected to provide protection from ICI. When used for uplink time and frequency synchronization, a network-initiated CFRA preamble may in some cases be used to track drifts in timing and frequency over time and, as opposed to initial synchronization and correction, these drifts may be much smaller than initial offsets. As a result, some of the CBRA techniques provided herein may not be needed for CFRA preambles in NTN. Thus, in some cases, properties for at least some CFRA preambles may be different from that of UE-initiated CBRA preambles for NB-IoT over NTN. Note that this is different than terrestrial NB-IoT, where the properties for both CFRA and CBRA preambles are the same. For example, CFRA preambles in NTN may follow terrestrial NB-IoT designs (e.g., legacy subcarrier spacing, unrestricted ninitwithin CFRA preamble space, legacy hopping patterns, legacy NscRA, etc.), while at least some CBRA preambles may incorporate some of the designs described herein for providing protection from ICI across CBRA preambles.

In some cases, network-initiated CFRA preamble transmission may be triggered by an NPDCCH order, where a particular encoding of DCI (e.g., DCI Format N1) may indicate to the UE the resource and preamble to transmit on NPRACH. In NTN deployments, the drift may follow a relatively pre-determined evolution, owing to the regular orbit of the satellite causing predictable Doppler shifts and the like. As a result, the network may determine that (e.g., every 10 seconds) the UE needs to correct its accumulated drift. For such use cases, for NB-IoT over NTN, a UE may be configured with a periodic transmission of CFRA preambles. The configuration may be via higher layers (e.g. RRC signaling), and may in some cases be activated or deactivated by DCI. In some cases, the activation/deactivation DCI may also adjust parameters such as transmission periodicity, first transmission occasion, and the like.

In some cases, timing corrections (e.g., timing advance (TA) commands) are provided by MAC control elements (CEs), which requires an NB-IoT UE to monitor an NPDSCH to receive such commands. An exception to this case is for transmission on a preconfigured uplink resource (PUR), where a DCI (on NPDCCH) can provide a TA command, thereby saving UE power from not having to monitor NPDSCH. Further, for NTN, a frequency correction command, similar to a TA command, may be provided to UEs in order to compensate frequency shifts. In some cases, an NB-IoT UE in an NTN may receive time and/or frequency correction commands in a physical layer DCI. In some cases, such commands may be provided in DCI if the time/frequency offsets relatively small (e.g., below a threshold value), and may be provided in a MAC-CE otherwise.

Additionally, due to relatively rapid change of satellite beams (e.g., especially for Low Earth Orbit (LEO) satellites), very large repetitions for NB-IoT channels (e.g., in accordance with coverage enhancement techniques designed for deep coverage) may not be feasible for NTN deployments. As a result, the supported NPRACH resource configurations (e.g., specifying a number of repetitions of a PRU) may be different for NTN versus terrestrial random access. In particular, the maximum number of repetitions supported for NPRACH in NTN may be less than the maximum number of repetitions supported for NPRACH in terrestrial.

FIG.5illustrates an example of a narrowband random access resources500that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. In some examples, narrowband random access resources500may implement aspects of wireless communications system100or200. In this example, periodic random access resources505may be configured.

In this example, random access resources505may include a first set of resources510with NTN preambles or restrictions (e.g., as discussed with reference toFIG.4) and a second set of resources515that are not different in properties and configuration to terrestrial preambles (e.g., without restrictions on selection of preambles as in terrestrial preambles). In some cases, the first set of resources510may be used for CBRA, and the second set of resources515may be used for CFRA. In other cases, both the first set of resources510and the second set of resources515may be used for CFRA, and only the first set of resources510may be used for CBRA. In the example ofFIG.5, periodicity of the random access resources505may be defined by an offset value520(S1) and period525(P1). Thus, random access resources505-amay occur at a time S1following a reference starting time, with subsequent instances of random access resources505-band505-coccurring according to period525. A UE operating in such a deployment may select a random access preamble based on the random access resources505.

FIG.6illustrates an example of a narrowband random access resources600that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. In some examples, narrowband random access resources600may implement aspects of wireless communications system100. In this example, again, periodic random access resources605may be configured.

In this example, random access resources605may include interleaved preambles610in which preambles having restrictions or parameters for NTN (e.g., as discussed with reference toFIG.4) are interleaved with preambles that are not different in properties and configuration to terrestrial preambles (e.g., without restrictions on selection of preambles as in terrestrial preambles). In some cases, the preambles having restrictions or parameters for NTN may be used for CBRA and the other interleaved preambles (i.e., without restrictions) may be used for CFRA. In this example, periodicity of the random access resources605may be defined by an offset value620(S1) and period625(P1). Thus, a first instance of random access resources605-amay occur at a time S1following a reference starting time, with a second instance of random access resources605-band a third instance of random access resources605-coccurring according to period625. A UE operating in such a deployment may select a random access preamble based on the random access resources605.

FIG.7illustrates an example of a narrowband random access resources700that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. In some examples, narrowband random access resources700may implement aspects of wireless communications system100or200. In this example, again, periodic random access resources705may be configured.

In this example, a first set of random access resources715may occur with a reduced periodicity as compared to a second set of random access resources710that have a longer periodicity. In some cases, the first set of random access resources715may have NTN preambles or restrictions (e.g., as discussed with reference toFIG.4) and the second set of resources710use preambles that are not different in properties and configuration to terrestrial preambles (e.g., without restrictions on selection of preambles as in terrestrial preambles). In some cases, the second set of random access resources710may be used for CFRA and may provide enhanced scheduling flexibility to a base station, while the first set of random access resources715may be used for CBRA. In this example, a first periodicity of the second set of random access resources710may be defined by a first offset value720(S1) and first period730(P1). In this example, a second periodicity of the first set of random access resources715may be defined by a second offset value725(S2) and second period735(P2).

In some cases, the second periodicity735may be greater than the first periodicity730, and thus provide that the second set of random access resources710has more resources than the first set of random access resources715. In such examples, UEs may be allocated resources for random access messages based on a likelihood of frequency error that may be present in communications from the UE. For example, the second set of random access resources710may be designed for UEs that have poor or no global navigation satellite system (GNSS) support, and as a result may have large residual frequency errors, and the first set of random access resources715may be designed for UEs with simultaneous GNSS and relatively little uncompensated error. In some cases, the first set of random access resources715(e.g., having the properties such as skipped starting subcarriers, etc.) may occur less frequently than the second set of random access resources710, so as to not unnecessarily lower overall random access capacity due to the presence of a relatively small number of UEs with poor or no GNSS support and/or poor internal compensation.

FIG.8shows a block diagram800of a device805that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. The device805may be an example of aspects of a UE115as described herein. The device805may include a receiver810, a communications manager815, and a transmitter820. The device805may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver810may 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 narrowband random access preambles for non-terrestrial network communications, etc.). Information may be passed on to other components of the device805. The receiver810may be an example of aspects of the transceiver1120described with reference toFIG.11. The receiver810may utilize a single antenna or a set of antennas.

The communications manager815may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network, and transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters. The communications manager815may be an example of aspects of the communications manager1110described herein.

The transmitter820may transmit signals generated by other components of the device805. In some examples, the transmitter820may be collocated with a receiver810in a transceiver module. For example, the transmitter820may be an example of aspects of the transceiver1120described with reference toFIG.11. The transmitter820may utilize a single antenna or a set of antennas.

The communications manager915may be an example of aspects of the communications manager815as described herein. The communications manager915may include a configuration manager920, a random access manager925, and a NTN communications manager930. The communications manager915may be an example of aspects of the communications manager1110described herein.

The configuration manager920may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network.

The random access manager925may select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network.

The NTN communications manager930may transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters.

The transmitter935may transmit signals generated by other components of the device905. In some examples, the transmitter935may be collocated with a receiver910in a transceiver module. For example, the transmitter935may be an example of aspects of the transceiver1120described with reference toFIG.11. The transmitter935may utilize a single antenna or a set of antennas.

FIG.10shows a block diagram1000of a communications manager1005that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. The communications manager1005may be an example of aspects of a communications manager815, a communications manager915, or a communications manager1110described herein. The communications manager1005may include a configuration manager1010, a random access manager1015, a NTN communications manager1020, a random access parameter manager1025, and a DCI manager1030. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The configuration manager1010may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. In some examples, the configuration manager1010may receive an indication of a first subset of the first set of narrowband random access parameters that provide contention-free random access resources and a second subset of the first set of narrowband random access parameters that provide contention-based random access resources, where the contention-free random access resources have one or more parameters that are different than corresponding parameters of the contention-based random access resources.

In some cases, the first set of narrowband random access parameters include a first set of random access preambles for contention-based random access that have one or more different characteristics than a second set of random access preambles of the second set of narrowband random access parameters. In some cases, the first set of random access preambles are configured from a first candidate set of random access preambles and the second set of random access preambles are configured from a second candidate set of random access preambles, where the first candidate set of preambles is a subset of the second candidate set of random access preambles. In some cases, the first set of narrowband random access parameters include a first subset of narrowband random access parameters that correspond to terrestrial network narrowband random access parameters and a second subset of narrowband random access parameters that are different than terrestrial network narrowband random access parameters.

In some cases, the first subset of narrowband random access parameters and the second subset of narrowband random access parameters are located in a same set of frequency resources and in different time resources, in different sets of frequency resources and a same set of time resources, or in different frequency and time resources. In some cases, the first set of narrowband random access parameters supports different random access resource configurations associated with one or more repetitions of a preamble repetition unit (PRU) than the second set of narrowband random access parameters. In some cases, a maximum number of preamble repetitions supported by the first set of narrowband random access parameters is less than the maximum number of repetitions supported by the second set of narrowband random access parameters for at least a subset of random access preamble configurations.

The random access manager1015may select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network. In some cases, the transmitting the random access message further includes transmitting one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access message transmissions. In some cases, the configuration for periodic contention-free random access resources is received from the base station in radio resource control signaling and activated based on activation signaling received in one or more of a medium access control (MAC) control element or a downlink control information communication from the base station. In some cases, the activation signaling includes information for adjustment of one or more parameters associated with the one or more further random access messages.

The NTN communications manager1020may transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters.

The random access parameter manager1025may adjacent starting subcarriers of the first set of starting subcarriers have a first frequency spacing that is larger than a second frequency spacing between adjacent starting subcarriers of the second set of starting subcarriers. In some cases, the first set of narrowband random access parameters include a first set of starting subcarriers allocated for contention-based random access preambles and is different from a second set of starting subcarriers allocated for contention-based random access preambles in the second set of narrowband random access parameters. In some cases, the first set of starting subcarriers allocated for contention-based random access preambles has fewer available starting subcarriers per unit of frequency than the second set of starting subcarriers. In some cases, the first set of starting subcarriers allocated for contention-based random access preambles has a different range of starting subcarriers within a total number of available starting subcarriers than the second set of starting subcarriers. In some cases, the first set of starting subcarriers includes one or more starting subcarriers that are allocated for contention-free random access preambles in the second set of narrowband random access parameters. In some cases, the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of the second set of starting subcarriers. In some cases, the first set of starting subcarriers are selected from the second set of starting subcarriers based on one or more of a starting subcarrier index value or a pattern of starting subcarriers from the second set of starting subcarriers.

In some cases, the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of a total number of available starting subcarriers allocated for contention-based and contention-free random access preambles in the second set of narrowband random access parameters. In some cases, the first set of random access preambles have one or more of a different intra-preamble repetition unit (PRU) frequency hopping pattern, a different inter-PRU frequency hopping pattern, a different subcarrier spacing, a different number of subcarriers spanned in frequency, or any combinations thereof, relative to the second set of random access preambles. In some cases, at least one intra-PRU hopping pattern provides that two random access preambles that are adjacent in frequency in a first portion of the PRU are non-adjacent in frequency in a second part of the PRU. In some cases, one or more preamble formats, preamble subcarrier spacings, or any combinations thereof of the second candidate set of random access preambles are precluded from the first candidate set of random access preambles.

In some cases, the first subset of narrowband random access parameters use random access parameters that are identical to those of terrestrial random access messages and the second subset of narrowband random access parameters use random access parameters specific to non-terrestrial random access messages. In some cases, the random access parameters include one or more of a set of starting subcarrier indices, a frequency hopping pattern for random access preambles, a subcarrier spacing, a number of subcarriers spanned in frequency, or any combinations thereof.

The DCI manager1030may receive, from the base station, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link.

FIG.11shows a diagram of a system1100including a device1105that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. The device1105may be an example of or include the components of device805, device905, or a UE115as described herein. The device1105may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager1110, an I/O controller1115, a transceiver1120, an antenna1125, memory1130, and a processor1140. These components may be in electronic communication via one or more buses (e.g., bus1145).

The communications manager1110may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network, and transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters.

The I/O controller1115may manage input and output signals for the device1105. The I/O controller1115may also manage peripherals not integrated into the device1105. In some cases, the I/O controller1115may represent a physical connection or port to an external peripheral. In some cases, the I/O controller1115may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, the I/O controller1115may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller1115may be implemented as part of a processor. In some cases, a user may interact with the device1105via the I/O controller1115or via hardware components controlled by the I/O controller1115.

In some cases, the wireless device may include a single antenna1125. However, in some cases the device may have more than one antenna1125, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory1130may include RAM and ROM. The memory1130may store computer-readable, computer-executable code1135including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory1130may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The code1135may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code1135may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code1135may not be directly executable by the processor1140but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

The receiver1210may 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 narrowband random access preambles for non-terrestrial network communications, etc.). Information may be passed on to other components of the device1205. The receiver1210may be an example of aspects of the transceiver1520described with reference toFIG.15. The receiver1210may utilize a single antenna or a set of antennas.

The communications manager1215may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters, and transmit a random access response to the UE via the satellite link responsive to the detecting. The communications manager1215may be an example of aspects of the communications manager1510described herein.

The transmitter1220may transmit signals generated by other components of the device1205. In some examples, the transmitter1220may be collocated with a receiver1210in a transceiver module. For example, the transmitter1220may be an example of aspects of the transceiver1520described with reference toFIG.15. The transmitter1220may utilize a single antenna or a set of antennas.

FIG.13shows a block diagram1300of a device1305that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. The device1305may be an example of aspects of a device1205, or a base station105as described herein. The device1305may include a receiver1310, a communications manager1315, and a transmitter1335. The device1305may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver1310may 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 narrowband random access preambles for non-terrestrial network communications, etc.). Information may be passed on to other components of the device1305. The receiver1310may be an example of aspects of the transceiver1520described with reference toFIG.15. The receiver1310may utilize a single antenna or a set of antennas.

The communications manager1315may be an example of aspects of the communications manager1215as described herein. The communications manager1315may include a configuration manager1320, a random access manager1325, and a NTN communications manager1330. The communications manager1315may be an example of aspects of the communications manager1510described herein.

The configuration manager1320may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network.

The random access manager1325may detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters.

The NTN communications manager1330may transmit a random access response to the UE via the satellite link responsive to the detecting.

The transmitter1335may transmit signals generated by other components of the device1305. In some examples, the transmitter1335may be collocated with a receiver1310in a transceiver module. For example, the transmitter1335may be an example of aspects of the transceiver1520described with reference toFIG.15. The transmitter1335may utilize a single antenna or a set of antennas.

FIG.14shows a block diagram1400of a communications manager1405that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. The communications manager1405may be an example of aspects of a communications manager1215, a communications manager1315, or a communications manager1510described herein. The communications manager1405may include a configuration manager1410, a random access manager1415, a NTN communications manager1420, a random access parameter manager1425, and a DCI manager1430. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The configuration manager1410may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network.

In some examples, the configuration manager1410may transmit an indication of a first subset of the first set of narrowband random access parameters that provide contention-free random access resources and a second subset of the first set of narrowband random access parameters that provide contention-based random access resources, where the contention-free random access resources have one or more parameters that are different than corresponding parameters of the contention-based random access resources. In some cases, the first set of narrowband random access parameters include a first set of random access preambles for contention-based random access that have one or more different characteristics than a second set of random access preambles of the second set of narrowband random access parameters. In some cases, the configuration for periodic contention-free random access resources is transmitted to the UE in radio resource control signaling and activated based on activation signaling transmitted in one or more of a medium access control (MAC) control element or a downlink control information communication from the base station. In some cases, the activation signaling includes information for adjustment of one or more parameters associated with the one or more further random access messages. In some cases, the first set of narrowband random access parameters supports different random access resource configurations associated with one or more repetitions of a preamble repetition unit (PRU) than the second set of narrowband random access parameters. In some cases, a maximum number of preamble repetitions supported by the first set of narrowband random access parameters is less than the maximum number of repetitions supported by the second set of narrowband random access parameters for at least a subset of random access preamble configurations.

The random access manager1415may detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters. In some cases, the receiving the random access message further includes receiving one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access message transmissions.

The NTN communications manager1420may transmit a random access response to the UE via the satellite link responsive to the detecting.

The random access parameter manager1425may adjacent starting subcarriers of the first set of starting subcarriers have a first frequency spacing that is larger than a second frequency spacing between adjacent starting subcarriers of the second set of starting subcarriers. In some cases, the first set of narrowband random access parameters include a first set of starting subcarriers allocated for contention-based random access preambles and is different from a second set of starting subcarriers allocated for contention-based random access preambles in the second set of narrowband random access parameters. In some cases, the first set of starting subcarriers allocated for contention-based random access preambles has fewer available starting subcarriers per unit of frequency than the second set of starting subcarriers. In some cases, the first set of starting subcarriers allocated for contention-based random access preambles has a different range of starting subcarriers within a total number of available starting subcarriers than the second set of starting subcarriers. In some cases, the first set of starting subcarriers includes one or more starting subcarriers that are allocated for contention-free random access preambles in the second set of narrowband random access parameters. In some cases, the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of the second set of starting subcarriers. In some cases, the first set of starting subcarriers are selected from the second set of starting subcarriers based on one or more of a starting subcarrier index value or a pattern of starting subcarriers from the second set of starting subcarriers. In some cases, the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of a total number of available starting subcarriers allocated for contention-based and contention-free random access preambles in the second set of narrowband random access parameters.

In some cases, the first set of random access preambles have one or more of a different intra-preamble repetition unit (PRU) frequency hopping pattern, a different inter-PRU frequency hopping pattern, a different subcarrier spacing, a different number of subcarriers spanned in frequency, or any combinations thereof, relative to the second set of random access preambles. In some cases, at least one intra-PRU hopping pattern provides that two random access preambles that are adjacent in frequency in a first portion of the PRU are non-adjacent in frequency in a second part of the PRU.

In some cases, the first set of random access preambles are configured from a first candidate set of random access preambles and the second set of random access preambles are configured from a second candidate set of random access preambles, where the first candidate set of preambles is a subset of the second candidate set of random access preambles. In some cases, one or more preamble formats, preamble subcarrier spacings, or any combinations thereof of the second candidate set of random access preambles are precluded from the first candidate set of random access preambles. In some cases, the first subset of narrowband random access parameters use random access parameters that are identical to those of terrestrial random access messages and the second subset of narrowband random access parameters use random access parameters specific to non-terrestrial random access messages. In some cases, the random access parameters include one or more of a set of starting subcarrier indices, a frequency hopping pattern for random access preambles, a subcarrier spacing, a number of subcarriers spanned in frequency, or any combinations thereof.

In some cases, the first set of narrowband random access parameters include a first subset of narrowband random access parameters that correspond to terrestrial network narrowband random access parameters and a second subset of narrowband random access parameters that are different than terrestrial network narrowband random access parameters. In some cases, the first subset of narrowband random access parameters and the second subset of narrowband random access parameters are located in a same set of frequency resources and in different time resources, in different sets of frequency resources and a same set of time resources, or in different frequency and time resources.

The DCI manager1430may transmit, to the UE, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link.

FIG.15shows a diagram of a system1500including a device1505that supports narrowband random access preambles for non-terrestrial network communications in accordance with aspects of the present disclosure. The device1505may be an example of or include the components of device1205, device1305, or a base station105as described herein. The device1505may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager1510, a network communications manager1515, a transceiver1520, an antenna1525, memory1530, a processor1540, and an inter-station communications manager1545. These components may be in electronic communication via one or more buses (e.g., bus1550).

The communications manager1510may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network, detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters, and transmit a random access response to the UE via the satellite link responsive to the detecting.

The network communications manager1515may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager1515may manage the transfer of data communications for client devices, such as one or more UEs115.

In some cases, the wireless device may include a single antenna1525. However, in some cases the device may have more than one antenna1525, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory1530may include RAM, ROM, or a combination thereof. The memory1530may store computer-readable code1535including instructions that, when executed by a processor (e.g., the processor1540) cause the device to perform various functions described herein. In some cases, the memory1530may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

At1605, the UE may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of1605may be performed according to the methods described herein. In some examples, aspects of the operations of1605may be performed by a configuration manager as described with reference toFIGS.8through11.

At1610, the UE may select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network. The operations of1610may be performed according to the methods described herein. In some examples, aspects of the operations of1610may be performed by a random access manager as described with reference toFIGS.8through11.

At1615, the UE may transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters. The operations of1615may be performed according to the methods described herein. In some examples, aspects of the operations of1615may be performed by a NTN communications manager as described with reference toFIGS.8through11.

At1705, the UE may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of1705may be performed according to the methods described herein. In some examples, aspects of the operations of1705may be performed by a configuration manager as described with reference toFIGS.8through11.

At1710, the UE may receive an indication of a first subset of the first set of narrowband random access parameters that provide contention-free random access resources and a second subset of the first set of narrowband random access parameters that provide contention-based random access resources, where the contention-free random access resources have one or more parameters that are different than corresponding parameters of the contention-based random access resources. The operations of1710may be performed according to the methods described herein. In some examples, aspects of the operations of1710may be performed by a configuration manager as described with reference toFIGS.8through11.

At1715, the UE may select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network. The operations of1715may be performed according to the methods described herein. In some examples, aspects of the operations of1715may be performed by a random access manager as described with reference toFIGS.8through11.

At1720, the UE may transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters. The operations of1720may be performed according to the methods described herein. In some examples, aspects of the operations of1720may be performed by a NTN communications manager as described with reference toFIGS.8through11.

At1805, the UE may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of1805may be performed according to the methods described herein. In some examples, aspects of the operations of1805may be performed by a configuration manager as described with reference toFIGS.8through11.

At1810, the UE may select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network. The operations of1810may be performed according to the methods described herein. In some examples, aspects of the operations of1810may be performed by a random access manager as described with reference toFIGS.8through11.

At1815, the UE may transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters. The operations of1815may be performed according to the methods described herein. In some examples, aspects of the operations of1815may be performed by a NTN communications manager as described with reference toFIGS.8through11.

At1820, the UE may the transmitting the random access message further includes transmitting one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access message transmissions. The operations of1820may be performed according to the methods described herein. In some examples, aspects of the operations of1820may be performed by a random access manager as described with reference toFIGS.8through11.

At1905, the UE may receive, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of1905may be performed according to the methods described herein. In some examples, aspects of the operations of1905may be performed by a configuration manager as described with reference toFIGS.8through11.

At1910, the UE may select, based on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network. The operations of1910may be performed according to the methods described herein. In some examples, aspects of the operations of1910may be performed by a random access manager as described with reference toFIGS.8through11.

At1915, the UE may transmit the random access message to the base station via the satellite link using the selected narrowband random access parameters. The operations of1915may be performed according to the methods described herein. In some examples, aspects of the operations of1915may be performed by a NTN communications manager as described with reference toFIGS.8through11.

At1920, the UE may receive, from the base station, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link. The operations of1920may be performed according to the methods described herein. In some examples, aspects of the operations of1920may be performed by a DCI manager as described with reference toFIGS.8through11.

At2005, the base station may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of2005may be performed according to the methods described herein. In some examples, aspects of the operations of2005may be performed by a configuration manager as described with reference toFIGS.12through15.

At2010, the base station may detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters. The operations of2010may be performed according to the methods described herein. In some examples, aspects of the operations of2010may be performed by a random access manager as described with reference toFIGS.12through15.

At2015, the base station may transmit a random access response to the UE via the satellite link responsive to the detecting. The operations of2015may be performed according to the methods described herein. In some examples, aspects of the operations of2015may be performed by a NTN communications manager as described with reference toFIGS.12through15.

At2105, the base station may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of2105may be performed according to the methods described herein. In some examples, aspects of the operations of2105may be performed by a configuration manager as described with reference toFIGS.12through15.

At2110, the base station may transmit an indication of a first subset of the first set of narrowband random access parameters that provide contention-free random access resources and a second subset of the first set of narrowband random access parameters that provide contention-based random access resources, where the contention-free random access resources have one or more parameters that are different than corresponding parameters of the contention-based random access resources. The operations of2110may be performed according to the methods described herein. In some examples, aspects of the operations of2110may be performed by a configuration manager as described with reference toFIGS.12through15.

At2115, the base station may detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters. The operations of2115may be performed according to the methods described herein. In some examples, aspects of the operations of2115may be performed by a random access manager as described with reference toFIGS.12through15.

At2120, the base station may transmit a random access response to the UE via the satellite link responsive to the detecting. The operations of2120may be performed according to the methods described herein. In some examples, aspects of the operations of2120may be performed by a NTN communications manager as described with reference toFIGS.12through15.

At2205, the base station may transmit, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network. The operations of2205may be performed according to the methods described herein. In some examples, aspects of the operations of2205may be performed by a configuration manager as described with reference toFIGS.12through15.

At2210, the base station may detect one or more random access messages from the UE via a satellite link of the non-terrestrial network based on the first set of narrowband random access parameters. The operations of2210may be performed according to the methods described herein. In some examples, aspects of the operations of2210may be performed by a random access manager as described with reference toFIGS.12through15.

At2215, the base station may transmit a random access response to the UE via the satellite link responsive to the detecting. The operations of2215may be performed according to the methods described herein. In some examples, aspects of the operations of2215may be performed by a NTN communications manager as described with reference toFIGS.12through15.

At2220, the base station may transmit, to the UE, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link. The operations of2220may be performed according to the methods described herein. In some examples, aspects of the operations of2220may be performed by a DCI manager as described with reference toFIGS.12through15.

Aspect 1: A method for wireless communication at a UE, comprising: receiving, from a base station, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network; selecting, based at least in part on the receiving, one or more narrowband random access parameters from the first set of narrowband random access parameters for a random access message to be transmitted to the base station via a satellite link of the non-terrestrial network; and transmitting the random access message to the base station via the satellite link using the selected narrowband random access parameters.

Aspect 2: The method of aspect 1, wherein the first set of narrowband random access parameters include a first set of starting subcarriers allocated for contention-based random access preambles that is different from a second set of starting subcarriers allocated for contention-based random access preambles in the second set of narrowband random access parameters.

Aspect 3: The method of aspect 2, wherein adjacent starting subcarriers of the first set of starting subcarriers have a first frequency spacing that is larger than a second frequency spacing between adjacent starting subcarriers of the second set of starting subcarriers.

Aspect 4: The method of any of aspects 2 through 3, wherein the first set of starting subcarriers allocated for contention-based random access preambles has fewer available starting subcarriers per unit of frequency than the second set of starting subcarriers.

Aspect 5: The method of any of aspects 2 through 4, wherein the first set of starting subcarriers has a different range of starting subcarriers within a total number of available starting subcarriers for contention-based random access and contention-free random access than that of the second set of starting subcarriers.

Aspect 6: The method of any of aspects 2 through 5, wherein the first set of starting subcarriers corresponds to a subset of the second set of starting subcarriers.

Aspect 7: The method of aspect 6, wherein the first set of starting subcarriers are selected from the second set of starting subcarriers based at least in part on one or more of a starting subcarrier index value or a pattern of starting subcarriers from the second set of starting subcarriers.

Aspect 8: The method of aspect 7, wherein the pattern of starting subcarriers comprises one out of every m consecutive starting subcarriers from the second set of starting subcarriers, where m is an integer.

Aspect 9: The method of any of aspects 2 through 8, wherein the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of a total number of available starting subcarriers allocated for contention-based and contention-free random access preambles in the second set of narrowband random access parameters, the first set of starting subcarriers is determined at least in part by a pattern of starting subcarriers from the second set of starting subcarriers.

Aspect 10: The method of aspect 9, wherein the pattern of starting subcarriers comprises one out of every m consecutive starting subcarriers from the total number of available starting subcarriers in the second set of narrowband random access parameters, where m is an integer.

Aspect 11: The method of any of aspects 1 through 10, wherein the first set of narrowband random access parameters include a first set of random access preambles for contention-based random access that have one or more different characteristics than a second set of random access preambles of the second set of narrowband random access parameters.

Aspect 12: The method of aspect 11, wherein the first set of random access preambles have one or more of a different intra-preamble repetition unit (PRU) frequency hopping pattern, a different inter-PRU frequency hopping pattern, a different subcarrier spacing, a different number of subcarriers spanned in frequency, or any combinations thereof, relative to the second set of random access preambles.

Aspect 13: The method of aspect 12, wherein at least one intra-PRU hopping pattern provides that two random access preambles that are adjacent in frequency in a first portion of the PRU are non-adjacent in frequency in a second portion of the PRU.

Aspect 14: The method of aspect 11, wherein the first set of random access preambles are configured from a first candidate set of random access preambles and the second set of random access preambles are configured from a second candidate set of random access preambles, the first candidate set of random access preambles is a subset of the second candidate set of random access preambles.

Aspect 15: The method of aspect 14, wherein one or more preamble formats, preamble subcarrier spacings, or any combinations thereof of the second candidate set of random access preambles are precluded from the first candidate set of random access preambles.

Aspect 16: The method of aspect 1, wherein the receiving the configuration information further comprises: receiving an indication of a first subset of the first set of narrowband random access parameters that provide a first subset of resources corresponding to the first subset of narrowband random access parameters and a second subset of the first set of narrowband random access parameters that provide a second subset of resources corresponding to the second subset of narrowband random access parameters, wherein the first subset of resources have one or more parameters that are different than corresponding parameters of the second subset of resources.

Aspect 17: The method of aspect 16, wherein the first subset of resources or the second subset of resources are any one of contention-based random access resources or contention-free random access resources.

Aspect 18: The method of any of aspects 16 through 17, wherein the first subset of narrowband random access parameters use random access parameters that are not different from those of terrestrial random access messages and the second subset of narrowband random access parameters use random access parameters specific to non-terrestrial random access messages.

Aspect 19: The method of any of aspects 16 through 18, wherein the narrowband random access parameters include one or more of a set of starting subcarrier indices, a frequency hopping pattern for random access preambles, a subcarrier spacing, a number of subcarriers spanned in frequency, or any combinations thereof.

Aspect 20: The method of any of aspects 16 through 19, wherein the first subset of resources and the second subset of resources are located in a same set of frequency resources and in different time resources, in different sets of frequency resources and a same set of time resources, in different frequency and time resources, or interlaced with each other within the same set of time and frequency resources.

Aspect 21: The method of aspect 20, wherein a first periodicity of the first subset of resources is different from a second periodicity of the second subset of resources.

Aspect 22: The method of any of aspects 1 through 21, wherein the transmitting the random access message further comprises transmitting one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access preamble message transmissions.

Aspect 23: The method of aspect 22, wherein the configuration for periodic contention-free random access preamble message transmissions is received from the base station in radio resource control signaling.

Aspect 24: The method of aspect 23, wherein the configuration for periodic contention-free random access preamble message transmissions is activated based at least in part on activation signaling received in one or more of a medium access control (MAC) control element or a downlink control information communication from the base station.

Aspect 25: The method of aspect 24, wherein the activation signaling includes information for adjustment of one or more parameters associated with the one or more further random access messages.

Aspect 26: The method of any of aspects 1 through 25, further comprising: receiving, from the base station, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link.

Aspect 27: The method of aspect 26, wherein the time or frequency correction command is provided in the physical layer downlink control information when an indicated correction value is less than a threshold value, and wherein the time or frequency correction command is provided in a medium access control (MAC) control element when the indicated correction value meets or exceeds the threshold value.

Aspect 28: The method of any of aspects 1 through 27, wherein the first set of narrowband random access parameters supports different random access resource configurations associated with one or more repetitions of a preamble repetition unit (PRU) than the second set of narrowband random access parameters.

Aspect 29: The method of aspect 28, wherein a maximum number of preamble repetitions supported by the first set of narrowband random access parameters is less than the maximum number of preamble repetitions supported by the second set of narrowband random access parameters for at least a subset of random access preamble configurations.

Aspect 30: A method for wireless communication at a base station, comprising: transmitting, to a UE, configuration information for a first set of narrowband random access parameters corresponding to random access messages transmitted over a non-terrestrial network that is different from a second set of narrowband random access parameters for random access messages transmitted over a terrestrial network; detecting one or more random access messages from the UE via a satellite link of the non-terrestrial network based at least in part on the first set of narrowband random access parameters; and transmitting a random access response to the UE via the satellite link responsive to the detecting.

Aspect 31: The method of aspect 30, wherein the first set of narrowband random access parameters include a first set of starting subcarriers allocated for contention-based random access preambles and is different from a second set of starting subcarriers allocated for contention-based random access preambles in the second set of narrowband random access parameters.

Aspect 32: The method of aspect 31, wherein adjacent starting subcarriers of the first set of starting subcarriers have a first frequency spacing that is larger than a second frequency spacing between adjacent starting subcarriers of the second set of starting subcarriers.

Aspect 33: The method of any of aspects 31 through 32, wherein the first set of starting subcarriers allocated for contention-based random access preambles has fewer available starting subcarriers per unit of frequency than the second set of starting subcarriers.

Aspect 34: The method of any of aspects 31 through 33, wherein the first set of starting subcarriers has a different range of starting subcarriers within a total number of available starting subcarriers for contention-based random access and contention-free random access than that of the second set of starting subcarriers.

Aspect 35: The method of any of aspects 31 through 34, wherein the first set of starting subcarriers corresponds to a subset of the second set of starting subcarriers.

Aspect 36: The method of aspect 35, wherein the first set of starting subcarriers are selected from the second set of starting subcarriers based at least in part on one or more of a starting subcarrier index value or a pattern of starting subcarriers from the second set of starting subcarriers.

Aspect 37: The method of aspect 31, wherein the first set of starting subcarriers allocated for contention-based random access corresponds to a subset of a total number of available starting subcarriers allocated for contention-based and contention-free random access preambles in the second set of narrowband random access parameters, the first set of starting subcarriers is determined at least in part by a pattern of starting subcarriers from the second set of starting subcarriers.

Aspect 38: The method of aspect 30, wherein the first set of narrowband random access parameters include a first set of random access preambles for contention-based random access that have one or more different characteristics than a second set of random access preambles of the second set of narrowband random access parameters.

Aspect 39: The method of aspect 38, wherein the first set of random access preambles have one or more of a different intra-preamble repetition unit (PRU) frequency hopping pattern, a different inter-PRU frequency hopping pattern, a different subcarrier spacing, a different number of subcarriers spanned in frequency, or any combinations thereof, relative to the second set of random access preambles.

Aspect 40: The method of aspect 39, wherein at least one intra-PRU hopping pattern provides that two random access preambles that are adjacent in frequency in a first portion of the PRU are non-adjacent in frequency in a second part of the PRU.

Aspect 41: The method of any of aspects 38 through 40, wherein the first set of random access preambles are configured from a first candidate set of random access preambles and the second set of random access preambles are configured from a second candidate set of random access preambles, the first candidate set of preambles is a subset of the second candidate set of random access preambles.

Aspect 42: The method of aspect 41, wherein one or more preamble formats, preamble subcarrier spacings, or any combinations thereof of the second candidate set of random access preambles are precluded from the first candidate set of random access preambles.

Aspect 43: The method of any of aspects 30 through 42, wherein the transmitting the configuration information further comprises: transmitting an indication of a first subset of the first set of narrowband random access parameters that provide resources corresponding to the first subset and a second subset of the first set of narrowband random access parameters that provide resources corresponding to the second subset, wherein the resources corresponding to the first subset have one or more parameters that are different than corresponding parameters of the second subset resources.

Aspect 44: The method of aspect 43, wherein the first subset of narrowband random access parameters use random access parameters that are not different from those of terrestrial random access messages and the second subset of narrowband random access parameters use random access parameters specific to non-terrestrial random access messages.

Aspect 45: The method of aspect 44, wherein the random access parameters include one or more of a set of starting subcarrier indices, a frequency hopping pattern for random access preambles, a subcarrier spacing, a number of subcarriers spanned in frequency, or any combinations thereof.

Aspect 46: The method of any of aspects 43 through 45, wherein the resources corresponding to the first subset and the resources corresponding to the second subset are located in a same set of frequency resources and in different time resources, in different sets of frequency resources and a same set of time resources, in different frequency and time resources, or interlaced with each other within the same set of time and frequency resources.

Aspect 47: The method of any of aspects 30 through 46, wherein the receiving the random access message further comprises receiving one or more further random access messages over the satellite link according to a configuration for periodic contention-free random access message transmissions.

Aspect 48: The method of aspect 47, wherein the configuration for periodic contention-free random access resources is transmitted to the UE in radio resource control signaling and activated based at least in part on activation signaling transmitted in one or more of a medium access control (MAC) control element or a downlink control information communication from the base station.

Aspect 49: The method of aspect 48, wherein the activation signaling includes information for adjustment of one or more parameters associated with the one or more further random access messages.

Aspect 50: The method of any of aspects 30 through 49, further comprising: transmitting, to the UE, in response to the random access message, a physical layer downlink control information communication that provides one or more of a time or frequency correction command for communications via the satellite link.

Aspect 51: The method of any of aspects 30 through 50, wherein the first set of narrowband random access parameters supports different random access resource configurations associated with one or more repetitions of a preamble repetition unit (PRU) than the second set of narrowband random access parameters.

Aspect 52: The method of aspect 51, wherein a maximum number of preamble repetitions supported by the first set of narrowband random access parameters is less than the maximum number of repetitions supported by the second set of narrowband random access parameters for at least a subset of random access preamble configurations.

Aspect 57: An apparatus for wireless communication at a base station, comprising at least one means for performing a method of any of aspects 30 through 52.