Random access to over-the-air user equipment in connected mode

Abstract

Methods, systems, and apparatus for wireless communications are described. In a wireless communications system, a base station may send an indication of a precompensation timing value for use in transmitting a random access message by an airborne user equipment (UE), the random access message being part of a random access procedure between the base station and the airborne UE when the airborne UE is in a connected state. The precompensation timing value may be based on a location of the airborne UE. In some examples, the base station may monitor a set of random access resources associated with the precompensation timing value and the airborne UE for the random access message, and the airborne UE may send the random access message using a first random access resource in the set of random access resources associated with the precompensation timing value and the airborne UE.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. patent application No. 17 / 461,611, entitled “RANDOMACCESSFOR AERIAL USER EQUIPMENTS IN CONNECTED MODE,” filed by Saha et al. on August 30, 2021, which has been assigned to the assignee of this application. Technical Field

[0003] The following relates to wireless communications including random access to an over-the-air user equipment (UE) in connected mode. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency and power). Examples of such multiple access systems include fourth generation (4G) systems, such as long term evolution (LTE) systems, advanced LTE (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems, which may be referred to as new radio (NR) systems. These systems may use techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each base station or network access node supporting communication of multiple communication devices simultaneously, which may also be referred to as user equipment (UE). Summary of the invention

[0005] The described techniques relate to improved methods, systems, devices, and apparatuses for supporting random access to an airborne user equipment (UE) in connected mode. In general, the described techniques allow an airborne UE in connected mode (e.g., connected state) to use an improved random access channel (RACH) procedure. In some examples, a base station may send a pre-compensated timing value (e.g., t pre) for a UE (e.g., an airborne UE) to use for transmission of a random access message. The random access message may be part of a RACH procedure between a base station and a UE when the UE is in connected mode, and the pre-compensation timing value may be based on the location of the UE. The UE may send a random access message using a first random access resource in a set of random access resources associated with the pre-compensation timing value and the UE, and the base station may monitor the set of random access resources associated with the pre-compensation timing value and the UE to obtain the random access message. In some examples, the base station may broadcast signaling indicating a plurality of pre-compensation timing values ​​to one or more UEs, wherein the pre-compensation timing values ​​may be associated with one or more areas (e.g., airborne coverage areas) supported by the base station. Additionally or alternatively, the UE may determine (e.g., calculate) a pre-compensation timing value based on the location of the UE, the location of the base station, or both.

[0006] A method for wireless communication at a base station is described. The method may include sending an indication of a precompensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and monitoring a set of random access resources for the random access message based on the indication, the set of random access resources being associated with the precompensation timing value and the airborne UE.

[0007] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to send an indication of a precompensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and to monitor a set of random access resources for the random access message and a set of random access resources associated with the precompensation timing value and the airborne UE based on the indication.

[0008] Another apparatus for wireless communication at a base station is described. The apparatus may include means for sending an indication of a precompensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and means for monitoring a set of random access resources for the random access message based on the indication, the set of random access resources being associated with the precompensation timing value and the airborne UE.

[0009] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to send an indication of a precompensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and to monitor a set of random access resources for the random access message based on the indication, the set of random access resources associated with the precompensation timing value and the airborne UE.

[0010] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending an indication of a pre-compensation timing value may include operations, features, units, or instructions for sending an indication of a pre-compensation timing value for a random access message transmitted by an airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE when the airborne UE may be in a connected state.

[0011] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending an indication of a pre-compensation timing value may include operations, features, units, or instructions for sending an indication to an airborne UE, the indication of the pre-compensation timing value being sent via radio resource control (RRC) signaling, a medium access control (MAC) control element (MAC-CE), or downlink control information (DCI), wherein the pre-compensation timing value may be specific to the airborne UE.

[0012] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending an indication of a precompensation timing value may include operations, features, means, or instructions for sending an index corresponding to a precompensation timing value for transmitting a random access message by an over-the-air UE.

[0013] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending an indication of a pre-compensation timing value may include operations, features, units, or instructions for sending broadcast signaling indicating a set of multiple regions and corresponding region identifiers, wherein each region in the set of multiple regions can be associated with a corresponding pre-compensation timing value for transmitting a random access message by an over-the-air UE.

[0014] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for sending an indication of an air UE activation area identifier to the air UE via a dedicated RRC message.

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for sending a bitmap to an air UE via a MAC-CE or a DCI to activate a region identifier for the air UE.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for maintaining a list including a set of multiple regions and corresponding pre-compensation timing values ​​based on one or more measurements associated with one or more aerial UEs.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, each precompensation timing value corresponds to a minimum value of precompensation for a corresponding zone of the random access preamble transmission.

[0018] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for receiving a capability message from an airborne UE indicating the ability of the airborne UE to perform operations such as measuring the position of the airborne UE, applying a pre-compensation timing value, or both.

[0019] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for sending a second message of a random access procedure after monitoring a set of random access resources for a random access message. The second message indicates a timing pre-compensation of the random access message.

[0020] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending an indication of a pre-compensation timing value may include operations, features, means, or instructions for sending signaling indicating the location of a base station via system information or dedicated RRC signaling.

[0021] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending an indication of a precompensation timing value may include an operation, feature, means, or instruction for sending signaling that configures a precompensation timing value offset to an over-the-air UE.

[0022] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for receiving a report based on completion of a random access procedure, the report indicating that a pre-compensation timing value was determined or used by the over-the-air UE.

[0023] A method for wireless communication at an airborne UE is described. The method may include receiving an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and based on receiving the indication, sending the random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE.

[0024] An apparatus for wireless communication at an airborne UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to receive an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and based on receiving the indication, to send the random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE.

[0025] Another apparatus for wireless communication at an airborne UE is described. The apparatus may include means for receiving an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE and means for sending the random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE based on the received indication.

[0026] A non-transitory computer-readable medium storing code for wireless communication at an airborne UE is described. The code may include instructions executable by a processor to receive an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE, and based on the received indication, transmit the random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE.

[0027] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a pre-compensation timing value may include operations, features, units, or instructions for receiving an indication of a pre-compensation timing value for transmission of a random access message by an airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE when the airborne UE may be in a connected state.

[0028] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a pre-compensation timing value may include operations, features, units, or instructions for receiving signaling indicating the location of a base station via system information or dedicated RRC signaling and determining the pre-compensation timing value based on the location of the base station.

[0029] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a precompensation timing value may include an operation, feature, unit, or instruction for receiving signaling that configures a precompensation timing value offset to an airborne UE and determines a precompensation timing value based on the precompensation timing value offset.

[0030] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for determining a pre-compensation timing value based on a location of the base station and a location of the UE in the air.

[0031] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for sending a report based on completion of the random access procedure, the report indicating a pre-compensation timing value determined by the over-the-air UE.

[0032] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include the following operations, features, units, or instructions: based on the pre-compensation timing value being available at the air UE, transmitting a random access message using the pre-compensation timing value via a second random access resource in a set of random access resources; and based on the pre-compensation timing value being unavailable at the air UE, transmitting a random access message via a third random access resource in the set of random access resources.

[0033] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for sending a capability message from an airborne UE indicating the capability of the airborne UE to perform the following operations: for measuring the position of the airborne UE, applying a pre-compensation timing value, or both.

[0034] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a pre-compensation timing value may include operations, features, units, or instructions for receiving an indication of a pre-compensation timing value from a base station via RRC signaling, MAC-CE, or DCI, wherein the pre-compensation timing value may be specific to an airborne UE.

[0035] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a pre-compensation timing value may include operations, features, means, or instructions for receiving an index corresponding to the pre-compensation timing value for transmission of a random access message by an over-the-air UE.

[0036] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving an indication of a pre-compensation timing value may include an operation, feature, unit, or instruction to receive broadcast signaling indicating a set of multiple areas and corresponding area identifiers, wherein each area in the set of multiple areas can be associated with a respective pre-compensation timing value for transmission of a random access message by an over-the-air UE.

[0037] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for receiving an indication to activate a region identifier for airborne UEs from a base station and via a dedicated RRC message.

[0038] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include receiving a bitmap from a base station and via a MAC-CE or a DCI to activate a zone identifier for an airborne UE.

[0039] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, each precompensation timing value corresponds to a minimum value of precompensation for a corresponding zone of the random access preamble transmission.

[0040] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for receiving a second message for a random access procedure after sending a random access message, the second message indicating a timing pre-compensation for the random access message. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 An example of a wireless communication system supporting random access to an over-the-air UE in connected mode in accordance with aspects of the present disclosure is shown.

[0042] Figure 2 An example of a wireless communication system supporting random access to an over-the-air UE in connected mode in accordance with aspects of the present disclosure is shown.

[0043] Figure 3 An example of a wireless communication system supporting random access to an over-the-air UE in connected mode in accordance with aspects of the present disclosure is shown.

[0044] Figure 4An example of a process flow supporting random access to an over-the-air UE in connected mode in accordance with aspects of the present disclosure is shown.

[0045] Figure 5 and Figure 6 A block diagram of an apparatus supporting random access to an over-the-air UE in connected mode is shown in accordance with aspects of the present disclosure.

[0046] Figure 7 A block diagram of a communications manager supporting random access to an over-the-air UE in connected mode is shown in accordance with aspects of the present disclosure.

[0047] Figure 8 A diagram of a system including devices supporting random access to an over-the-air UE in connected mode is shown in accordance with aspects of the present disclosure.

[0048] Fig. 9 and Fig.10 A block diagram of an apparatus supporting random access to an over-the-air UE in connected mode is shown in accordance with aspects of the present disclosure.

[0049] Fig.11 A block diagram of a communications manager supporting random access to an over-the-air UE in connected mode is shown in accordance with aspects of the present disclosure.

[0050] Fig.12 A diagram of a system including devices supporting random access to an over-the-air UE in connected mode is shown in accordance with aspects of the present disclosure.

[0051] Figures 13 to 17 A flow chart illustrating a method of supporting random access to an over-the-air UE in connected mode in accordance with aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0052] A wireless multiple access communication system may include multiple base stations or network access nodes, each of which supports communication of multiple communication devices simultaneously, and the multiple communication devices may be further referred to as user equipment (UE). In some wireless communication systems, the UE may include an aerial UE, which may be a device capable of flying or manipulating in the air. An example of an aerial UE is an unmanned aerial vehicle (UAV), which may also be referred to as a drone. Some aerial UEs may support uplink or downlink communications with one or more base stations or sidelink communications between each other.

[0053] In some examples, a base station may support different coverage areas for ground and air communications. For example, a base station may cover an air coverage (e.g., volume) that is larger than ground coverage (e.g., area). During a random access channel (RACH) process, a UE may send a preamble in a random access message (e.g., Msg1, MsgA) to establish communication with a base station. However, due to the different coverage areas supported by the base station, an air UE may send a random access message that arrives at the base station with a longer propagation delay than a ground UE. In this way, an air UE in a radio resource control (RRC) connection mode may send a random access message slowly depending on the location of the base station and the air UE, which may increase latency and reduce transmission speed. In addition, although a ground UE may use timing advance to perform a RACH process, the air UE may be at a sufficiently large distance from the base station that the preamble used to calculate the timing advance may be insufficient for the air UE. In this way, it may be beneficial to apply a pre-compensated timing value before performing a RACH process so that the air UE can reuse the random access resources used by the ground UE.

[0054] The techniques described herein enable an airborne UE in a connected mode (e.g., a connected state) to use an improved RACH procedure. In some examples, a base station may send a pre-compensated timing value (e.g., t pre ) for a UE (e.g., an airborne UE) to use for transmission of a random access message. The random access message may be part of a RACH procedure between a base station and a UE when the UE is in connected mode, and the pre-compensation timing value may be based on the location of the UE. The UE may send a random access message using a first random access resource in a set of random access resources associated with the pre-compensation timing value and the UE, and the base station may monitor the set of random access resources associated with the pre-compensation timing value and the UE to obtain the random access message. In some examples, the base station may broadcast signaling indicating a plurality of pre-compensation timing values ​​to one or more UEs, wherein the pre-compensation timing values ​​may be associated with one or more areas (e.g., airborne coverage areas) supported by the base station. Additionally or alternatively, the UE may determine (e.g., calculate) a pre-compensation timing value based on the location of the UE, the location of the base station, or both.

[0055] Certain aspects of the subject matter described herein may be implemented to achieve one or more advantages. The described techniques may support improvements to RACH procedures for airborne UEs in connected mode. For example, in some cases, the described techniques may enable a UE to send a random access message associated with a RACH procedure with reduced propagation delay, which may reduce latency and improve user experience. Thus, the supported techniques may include improved network operation, and in some examples, may increase network efficiency, among other benefits.

[0056] Various aspects of the present disclosure are initially described in the context of a wireless communication system. Various aspects of the present disclosure are then described in the context of a process flow. Various aspects of the present disclosure are further illustrated and described by apparatus diagrams, system diagrams, and flow charts related to random access of an airborne UE in connected mode.

[0057] Figure 1 An example of a wireless communication system 100 supporting random access to a UE in a connected mode according to aspects of the present disclosure is shown. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communication, ultra-reliable communication, low latency communication, communication with low-cost and low-complexity devices, or any combination thereof.

[0058] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100 and may be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support signal communication according to one or more radio access technologies.

[0059] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, mobile, or both at different times. The UEs 115 may be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. 1. The UEs 115 described herein can communicate with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices), such as Figure 1 shown.

[0060] The base stations 105 may communicate with the core network 130, or with each other, or both. For example, the base stations 105 may interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105), or indirectly (e.g., via the core network 130), or both via the backhaul links 120 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul links 120 may be or include one or more wireless links.

[0061] The one or more base stations 105 described herein may include or may be referred to by a person of ordinary skill in the art as a base station transceiver, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next generation NodeB or a giga NodeB (both may be referred to as gNBs), a Home NodeB, a Home eNodeB, or other suitable terminology.

[0062] UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where a "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, and other examples.

[0063] The UE 115 described herein can communicate with various types of devices, such as other UEs 115, which can sometimes act as relays, as well as base stations 105 and network devices, including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, such as Figure 1 shown.

[0064] The UE 115 and the base station 105 can communicate with each other wirelessly via one or more communication links 125 through one or more carriers. The term "carrier" can refer to a collection of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, the carrier used for the communication link 125 may include a portion of a radio frequency spectrum band (a physical layer channel (e.g., a bandwidth portion (BWP)) operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR)). Each physical layer channel can carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operations, user data, or other signaling. The wireless communication system 100 can use carrier aggregation or multi-carrier operation to support communication with the UE 115. The UE 115 can be configured with multiple downlink component carriers and one or more uplink component carriers according to the carrier aggregation configuration. Carrier aggregation can be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0065] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations with respect to other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel raster for discovery by a UE 115. A carrier may operate in a standalone mode, where initial acquisition and connection may be performed by a UE 115 via the carrier, or the carrier may operate in a non-standalone mode, where a different carrier is used to anchor the connection (e.g., the same or different radio access technology).

[0066] The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry both downlink and uplink communications (e.g., in TDD mode).

[0067] A carrier may be associated with a particular bandwidth of a radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as a "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of a plurality of determined bandwidths of a carrier for a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). The devices of the wireless communication system 100 (e.g., a base station 105, a UE 115, or both) may have a hardware configuration that supports communication on a particular carrier bandwidth, or may be configured to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communication via carriers associated with a plurality of carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., a subband, a BWP) or all of the carrier bandwidth.

[0068] The signal waveform transmitted through the carrier wave may be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system using MCM techniques, a resource element may be composed of a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period is inversely proportional to the subcarrier spacing. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Therefore, the more resource elements received by the UE 115 and the higher the order of the modulation scheme, the higher the data rate for the UE 115 can be. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity used to communicate with the UE 115.

[0069] The time interval for the base station 105 or the UE 115 may be expressed as a multiple of a basic time unit, for example, the basic time unit may be referred to as T s =1 / (Δf max ·N f ) seconds sampling period, where Δf max It can represent the maximum supported subcarrier spacing, and N f The maximum supported discrete Fourier transform (DFT) size may be indicated. The time intervals of the communication resources may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0070] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, the frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into multiple time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include multiple symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, the time slot may be further divided into multiple mini-time slots containing one or more symbols. In addition to the cyclic prefix, each symbol period may contain one or more (e.g., N f ) sampling period. The duration of a symbol period may depend on the subcarrier spacing or the frequency band of operation.

[0071] A subframe, slot, mini-slot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI)).

[0072] Physical channels can be multiplexed on a carrier according to various techniques. For example, a physical control channel and a physical data channel can be multiplexed on a downlink carrier using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. A control region (e.g., a control resource set (CORESET)) for a physical control channel can be defined by multiple symbol periods and can extend across a system bandwidth or a subset of a system bandwidth of a carrier. One or more control regions (e.g., CORESETs) can be configured for a set of UEs 115. For example, one or more UEs 115 can monitor or search a control region to obtain control information according to one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate can refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with a coding information format for a given payload size. A search space set can include a common search space set configured to send control information to multiple UEs 115 and a UE-specific search space set for sending control information to a specific UE 115.

[0073] Each base station 105 can provide communication coverage via one or more cells, such as macro cells, small cells, hot spots, or other types of cells, or any combination thereof. The term "cell" can refer to a logical communication entity used to communicate with the base station 105 (e.g., via a carrier), and can be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) for distinguishing adjacent cells. In some examples, a cell can also refer to a geographic coverage area 110 or a portion (e.g., a sector) of a geographic coverage area 110 on which a logical communication entity operates. Depending on various factors such as the capabilities of the base station 105, such a cell can range from a smaller area (e.g., a building, a subset of a building) to a larger area. For example, a cell can be or include a building, a subset of a building, or an external space between or overlapping a geographic coverage area 110, as well as other examples.

[0074] A macro cell generally covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to UEs 115 with service subscriptions to network providers that support macro cells. Small cells may be associated with lower-power base stations 105 than macro cells, and small cells may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to UEs 115 with service subscriptions to network providers, or may provide restricted access to UEs 115 associated with small cells (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). A base station 105 may support one or more cells, and may also support communication through the one or more cells using one or more component carriers.

[0075] In some examples, an operator may support multiple cells and may configure different cells based on different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access to different types of devices.

[0076] In some examples, base stations 105 may be mobile and thus provide communication coverage for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. For example, the wireless communication system 100 may include a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0077] The wireless communication system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and in some examples, transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operation.

[0078] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide automatic communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communication or MTC may include communication from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application that utilizes the information or presents the information to a human interacting with the application. Some UEs 115 may be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and business-based commercial charging.

[0079] Some UEs 115 may be configured to employ an operating mode that reduces power consumption, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception, but not simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power saving techniques for UE 115 include entering a power saving deep sleep mode when not engaged in active communications, operating over a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs 115 may be configured to operate using a narrowband protocol type that is associated with a defined portion or range (e.g., a subcarrier or resource block (RB)) within a carrier, within a guard band of a carrier, or outside a carrier.

[0080] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC). UE 115 can be designed to support ultra-reliable, low-latency or critical functions. Ultra-reliable communication can include private communication or group communication, and can be supported by one or more services such as voice push, video or data. Support for ultra-reliable, low-latency functions can include determination of service priorities, and such services can be used for public safety or general commercial applications. The terms "ultra-reliable", "low latency" and "ultra-reliable low latency" can be used interchangeably in this article.

[0081] In some examples, UE 115 may also be able to communicate directly with other UE 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication may be within a geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105, or otherwise unable to receive transmissions from the base station 105. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, wherein each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates resource scheduling for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0082] In some systems, the D2D communication link 135 can be an example of a communication channel (e.g., a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, vehicles can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. Vehicles can send signal information related to traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some examples, vehicles in a V2X system can communicate with the network via one or more network nodes (e.g., base station 105) using vehicle-to-network (V2N) communication, or communicate with roadside infrastructure (e.g., roadside units), or both.

[0083] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connection, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a fifth generation (5G) core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets or interconnects to an external network (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by a base station 105 associated with the core network 130. User IP packets may be transferred through a user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to IP services 150 of one or more network operators. IP services 150 may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0084] Some network devices, such as base stations 105, may include subcomponents such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with a UE 115 through one or more other access network transport entities 145, which may be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or merged into a single network device (e.g., base station 105).

[0085] The wireless communication system 100 can operate using one or more frequency bands typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). In general, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelength ranges from about one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, but the waves can penetrate the structure sufficiently to allow a macro cell to provide services to a UE 115 located indoors. Compared to transmission using a lower frequency and a longer wavelength in the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz, transmission of UHF waves may be associated with a smaller antenna and a shorter transmission distance (e.g., less than 100 kilometers).

[0086] The wireless communication system 100 can utilize both licensed radio frequency spectrum bands and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 can adopt licensed assisted access (LAA), LTE-unlicensed (LTE-U) radio access technology, or NR technology in unlicensed bands (e.g., 5GHz industrial, scientific and medical (ISM) bands). When operating in unlicensed radio frequency spectrum bands, devices such as base stations 105 and UEs 115 can use carrier sensing to detect and avoid collisions. In some examples, operations in unlicensed bands can be based on carrier aggregation configurations combined with component carriers operating in licensed bands (e.g., LAA). Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, as well as other examples.

[0087] The base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array with multiple rows and columns of antenna ports, which the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays, which may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0088] The base station 105 or UE 115 can use MIMO communication to exploit multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. Such a technology may be referred to as spatial multiplexing. For example, multiple signals may be sent by a transmitting device via different antennas or different antenna combinations. Similarly, multiple signals may be received by a receiving device via different antennas or different antenna combinations. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technologies include: single-user MIMO (SU-MIMO), in which multiple spatial layers are sent to the same receiving device; and multi-user MIMO (MU-MIMO), in which multiple spatial layers are sent to multiple devices.

[0089] Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals transmitted via antenna elements of an antenna array so that some signals propagating at a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustment of signals transmitted via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each of the antenna elements may be defined by a set of beamforming weights associated with a specific orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0090] The wireless communication system 100 can be a packet-based network operated according to a layered protocol stack. In the user plane, the communication at the bearer layer or the packet data convergence protocol (PDCP) layer can be based on IP. The radio link control (RLC) layer can perform packet segmentation and reorganization to communicate through logical channels. The medium access control (MAC) layer can perform priority processing and multiplex logical channels into transport channels. The MAC layer can also use error detection technology, error correction technology or both to support retransmission at the MAC layer to improve link efficiency. In the control plane, the RRC protocol layer can provide the establishment, configuration and maintenance of the RRC connection between the UE115 and the base station 105 or the core network 130 supporting the radio bearer for user plane data. At the physical layer, the transport channel can be mapped to the physical channel.

[0091] The wireless communication system 100 may include multiple base stations 105 or network access nodes, each of which supports communication for multiple communication devices (e.g., UE 115) at the same time. In some wireless communication systems 100, UE 115 may include an aerial UE, which may be a device capable of flying or maneuvering in the air. An example of an aerial UE is a UAV, which may also be referred to as a drone. In some examples, the aerial UE may communicate with an aerial UE controller, which may be referred to as a UAV controller (UAVC), which may control the aerial UE (e.g., using the Internet, Bluetooth, or any form of radio frequency communication). Additionally or alternatively, the aerial UE may be configured with a radio access network (RAN) device and may communicate with a base station 105 or other network entity via the RAN (e.g., using a third generation partnership project (3GPP) technology, such as a 5G NR network). Some aerial UEs may support uplink or downlink communication with one or more base stations 105 or sidelink communication with each other.

[0092] Aerial UE may include at least two separate entities or components. Flight-related components may perform some or all functions such as flight, maneuvering (e.g., avoiding obstacles), navigation, landing and takeoff, and may include power supplies (e.g., batteries or hydrogen batteries), electric or other types of motors, propellers, sensors and controllers. Communication-related components may perform functions associated with communications with ground controllers or other entities such as wireless communication systems 100, and may employ wireless technologies such as 4G LTE, 5G NR or both. Communication-related components may perform functions common to non-aerial wireless devices such as smartphones, tracking devices or IoT devices, and may be referred to as UE 115. These two components may share some resources (e.g., power supplies, processors and memories) and may coordinate and interact to control the flight path, navigation and maneuvering of aerial UEs. As discussed herein, aerial UE may refer only to communication-related components, only to flight-related components, or to both components. Aerial UE may be a UAV and these two terms may be used interchangeably herein.

[0093] In some examples, when UE 115 (e.g., an airborne UE) is in RRC connected mode, UE 115 may perform a random access procedure. For example, UE 115 may perform contention-free random access, wherein a dedicated RACH configuration may be optional for a connected UE 115 (e.g., a UE in RRC connected mode). That is, if the base station 105 configures UE 115 with a dedicated RACH configuration, UE 115 may perform contention-free random access. In contention-free random access, the base station 105 may send a random access preamble assignment to UE 115. In response, UE 115 may send a random access preamble (e.g., Msg1) to the base station 105, and the base station 105 may send a random access response (e.g., Msg2) to UE 115. In some examples, if the base station 105 avoids configuring UE 115 for contention-free random access, UE 115 may perform contention-based random access. In contention-based random access, UE 115 may send a random access preamble (e.g., Msg1) to base station 105. Base station 105 may send a random access response (e.g., Msg2) to UE 115, and in response UE 115 may schedule a physical uplink shared channel (PUSCH) transmission (e.g., Msg3) with base station 105. Base station 105 may then transmit a contention resolution solution (e.g., Msg4) to UE 115.

[0094] The random access process can be triggered by multiple events. For example, UE 115 can perform a random access process to obtain random access from an idle state (e.g., RRC_IDLE). When the uplink synchronization state of UE 115 is "non-synchronous", UE 115 can also use the random access process during the RRC connection reestablishment process, or after the downlink or uplink data arrives during the connected state (e.g., RRC_CONNECTED). In some examples, when UE 115 lacks physical uplink control channel (PUCCH) resources for scheduling requests, the random access process can be triggered after the uplink data arrives during the connected state (e.g., RRC_CONNECTED). In addition or alternatively, the random access process can be triggered after the scheduling request fails, based on a request via RRC signaling after synchronization reconfiguration (e.g., switching), or based on the UE 115 transitioning from an inactive state (e.g., RRC_INACTIVE). In some examples, if the measurement report is used to add a secondary cell, the random access process can be triggered to establish time alignment for a secondary timing advance group (TAG). In some cases, UE 115 may request additional system information, may perform a beam failure recovery procedure, or may experience consistent uplink listen-before-talk (LBT) failure on a special cell (Spcell), each of which may trigger a random access procedure.

[0095] In some examples, the random access process can be triggered based on the handover process of UE 115 with the source base station and the target base station (e.g., two or more base stations 105). For example, the source base station can initiate the handover and send a handover request (e.g., HANDOVER REQUEST) to the target base station through the Xn interface. The target base station can perform admission control and can provide a new RRC configuration as part of the confirmation of the handover request (e.g., HANDOVER REQUEST ACKNOWLEDGEMENT). In some cases, the source base station can provide the RRC configuration to UE 115 by forwarding the RRC reconfiguration message (e.g., RRCReconfiguration) received in the confirmation. The RRC reconfiguration message may include at least a cell identifier (ID) and information for accessing the target cell, so that UE 115 can access the target cell while avoiding reading system information. In some cases, information for contention-based random access and contention-free random access may be included in the RRC reconfiguration message. The access information to the target cell may include beam-specific information (if any). In some examples, based on receiving the RRC reconfiguration message, UE 115 can perform a random access procedure with the target base station, wherein UE 115 can move the RRC connection to the target base station (e.g., switch to a new cell) and reply a completion message (e.g., RRCReconfigurationComplete) to the target base station.

[0096] In some examples, a UE 115 (e.g., an airborne UE) in RRC connected mode may send Msg1 (e.g., MsgA) as part of a RACH process, where Msg1 may be a preamble of the first message sent in the RACH process. UE 115 may receive a timing reference from a downlink frame sent by base station 105. The downlink frame may take time t1 to reach UE 115, where t1=d1 / c, d1 may represent the distance between UE 115 and base station 105, and c may represent the speed of light. In some cases, UE 115 may align the transmission of an uplink random access preamble with the downlink frame timing. UE 115 may then send a random access preamble with a delay t1 (e.g., a propagation delay), and base station 105 may receive the random access preamble with a delay t1. As such, the UE 115 and the base station 105 may experience a total round trip delay of 2t1 between the base station 105 sending the timing reference and the base station 105 receiving the random access preamble (eg, Msg1).

[0097] To reduce round-trip delay and increase communication speed, the techniques described herein enable a UE 115 in connected mode (e.g., an airborne UE) to use an improved RACH procedure. In some examples, the base station 105 may send a pre-compensated timing value (e.g., t pre ) for the UE 115 to use for transmission of a random access message. When the UE 115 is in a connected mode (e.g., RRC_CONNECTED), the random access message may be part of a RACH process between the base station 105 and the UE 115, and the pre-compensation timing value may be based on the location of the UE 115. The UE 115 may send the random access message using a first random access resource in a set of random access resources associated with the pre-compensation timing value and the UE 115, and the base station 105 may monitor the set of random access resources associated with the pre-compensation timing value and the UE 115 to obtain the random access message. In some examples, the base station 105 may broadcast signaling indicating a plurality of pre-compensation timing values ​​to one or more UEs 115, wherein the pre-compensation timing values ​​may be associated with one or more regions (e.g., air coverage regions) supported by the base station 105. Additionally or alternatively, the UE 115 may determine (e.g., calculate) the pre-compensation timing value based on the location of the UE 115, the location of the base station 105, or both.

[0098] Figure 2 An example of a wireless communication system 200 that supports random access to an airborne UE in a connected mode in accordance with aspects of the present disclosure is shown. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100 or can be implemented by aspects of the wireless communication system 100. For example, the wireless communication system 200 can include a base station 105-a and a UE 115-a. It can be an example of a corresponding device described herein. The wireless communication system 200 can include features for improving communication between the base station 105-a and the UE 115-a and other benefits.

[0099] In some cases, the ground and air coverage of a cell may be different. For example, the wireless communication system 200 may include one or more cells 205 that may support ground coverage and a cell 210 (e.g., cell 210-a) that may support air coverage. That is, the cell 205 may support coverage of a ground area, and the cell 210-a may support an air coverage area 215, which may be a volume above the cell 210-a and may be larger than the area on the ground covered by the cell 205. Due to the different coverage, during random access, an air UE may send a preamble with a longer propagation delay than a ground UE to reach the base station 105-a.

[0100] The wireless communication system 200 may implement techniques for improved random access to an airborne UE in a connected mode (e.g., a connected state). For example, the wireless communication system 200 may support a RACH procedure between a base station 105-a and a UE 115-a, where the UE 115-a may be an airborne UE. In some examples, the UE 115-a may communicate with the base station 105-a via a communication link 220, which may be supported by a cell 210-a. In this way, the UE 115-a may be located in an airborne coverage area 215. The base station 105-a may send a pre-compensated timing value (e.g., t pre ) for UE 115-a to use for transmission of random access message 230. Random access message 230 may be part of a RACH procedure between base station 105-a and UE 115-a when UE 115-a is in connected mode, wherein the pre-compensation timing value may be based on the location of UE 115-a. UE 115-a may send random access message 230 using a first random access resource in a set of random access resources associated with the pre-compensation timing value and UE 115a, and base station 105-a may monitor the set of random access resources associated with the pre-compensation timing value and UE 115-a for random access message 230.

[0101] In some cases, the precompensation timing value may be determined by the base station 105-a (e.g., on the network side) and signaled to the UE 115-a via the communication link 220. In some examples, the base station 105-a may maintain a list of regions and a corresponding precompensation timing value for each of the regions. A region may represent an area on the surface of the Earth (e.g., supported by the cell 205) or a volume in the sky covered by the base station 105-a (e.g., supported by the cell 210-a).

[0102] In some examples, the pre-compensation timing value for each region may be the minimum value of the pre-compensation timing for a physical RACH (PRACH) preamble transmission. That is, each pre-compensation timing value may correspond to the minimum value of the pre-compensation for the corresponding region for a RACH preamble transmission (e.g., Msg1, MsgA). In some examples, the base station 105-a may maintain regions and corresponding pre-compensation timing values ​​by configuring recorded measurements for one or more aerial UEs (including UE 115-a). For example, the base station 105-a may maintain a list of regions and corresponding pre-compensation timing values ​​based on one or more measurements associated with one or more aerial UEs, where the measurements may correspond to the location of the aerial UE. In this way, the base station 105-a may have prior information on the volume or coverage area that the base station 105-a can support, which may be indicated by the region. For each region, the base station 105-a may record the pre-compensation timing factor, and the base station 105-a may continue to update the factor based on periodic measurements from the aerial UE.

[0103] The base station 105-a may indicate the pre-compensation timing value to the UE 115-a via one or more methods. In some examples, the base station 105-a may signal the UE-specific pre-compensation timing value to the corresponding UE 115 via dedicated RRC signaling. For example, during a handover process, the base station 105-a may signal the pre-compensation timing value in an RRC reconfiguration message (e.g., RRCReconfiguration). Additionally or alternatively, the base station 105-a may signal the pre-compensation timing value to the UE 115-a using a MAC control element (MAC-CE) or downlink control information (DCI).

[0104] In some examples, the precompensation timing value may be predefined (e.g., by the base station 105-a), and the base station 105-a may use RRC signaling, MAC-CE, or DCI to send an index corresponding to the precompensation timing value to the UE 115-a for the UE 115-a to transmit the random access message 230. That is, from the list of regions and the corresponding precompensation timing values, the base station 105-a may indicate the index of one or more regions and the corresponding precompensation timing value to the UE 115-a. In some cases, the index may be mapped to the precompensation timing value. Additionally or alternatively, the base station 105-a may broadcast a list including the region ID and the corresponding precompensation timing value for each region to one or more UEs 115 in a broadcast message (e.g., a system information block (SIB)). That is, the base station 105-a may broadcast signaling indicating multiple precompensation timing values ​​to one or more airborne UEs, wherein the precompensation timing value may be associated with one or more regions supported by the base station 105-a. For example, one or more airborne UEs may be located in airborne coverage area 215, and one or more airborne UEs may be located in different airborne coverage areas. Based on which airborne coverage area the airborne UE is located, base station 105-a may indicate different pre-compensation timing values. In some cases, base station 105-b may activate one or more area IDs by sending a bitmap to UE 115-b via an indication via MAC-CE or DCI or via a dedicated RRC message.

[0105] The base station 105-a can obtain the location of the UE 115-a to calculate the pre-compensation timing value. For example, when in a connected mode (e.g., RRC_CONNECTED), the base station 105-a can configure the UE 115-a to report location measurements (e.g., via MeasObj and ReportConfig) via dedicated signaling (e.g., RRCReconfiguration or RRCResume). The base station 105-a can configure the UE 115-a to send periodic location measurements to the base station 105-a. In some examples, a base station 105-a with multiple antennas can estimate the direction of the UE 115-a based on the angle of arrival of an uplink signal sent by the UE 115-a. The base station 105-a can estimate the distance from the latest timing advance for the UE 115-a without using additional signaling. In some cases, base station 105-a can obtain the location of UE 115-a by querying a location server, which may include using new signaling in LTE Positioning Protocol A (LPPa), NR Positioning Protocol A (NRPPa), or both.

[0106] In some examples, UE 115-b can estimate its own position and can use the position to calculate a pre-compensation timing value. In some examples, the location of base station 105-a can be signaled to UE 115-a. For example, base station 105-a can send signaling indicating the location of base station 105-a via broadcast system information (e.g., SIB1) or via dedicated RRC signaling. If UE 115-a can perform random access to the same cell, the location of base station 105-a can be the location of the same base station 105. In some cases, during a handover process, the location of the target base station can be provided via an RRC reconfiguration message (e.g., RRCReconfiguration).

[0107] In some cases, base station 105-a may send signaling to configure a pre-compensation timing value offset to UE 115-a. When determining the pre-compensation timing value, UE 115-a may use the pre-compensation timing value minus the offset to avoid over-compensation. In some examples, UE 115-a may be able to measure its own position and may calculate the pre-compensation timing value according to equation (1):

[0108]

[0109] Where (x gNB ,y gNB ,z gNB ) can represent the coordinates of base station 105-a, (x UE ,y UE ,z UE ) may represent the coordinates of UE 115-a, and c may represent the speed of light. That is, UE 115-a may determine the pre-compensation timing value based on the location of base station 105-a and the location of UE 115-a.

[0110] In some examples, UE 115-a may report the determined or used pre-compensation timing value to base station 105-a. For example, UE 115-a may send a report indicating the pre-compensation value determined or used by UE 115-a based on the completion of the RACH process. In some cases, for contention-based or contention-free random access, UE 115-a may use MAC-CE to report the pre-compensation timing value to base station 105-a. For example, MAC-CE may include 8 bits, wherein a 2-bit TAG ID may refer to a primary cell (Pcell) or a secondary cell (Scell) corresponding to base station 105-a, and the preamble timing compensation may be encoded as a 6-bit message. Once the RACH process is completed, UE 115-a may send a MAC-CE to base station 105-a. In some examples, UE 115-a may avoid reporting the pre-compensation timing value. Even when base station 105-a indicates a timing advance after the RACH process, UE 115-a may continue to apply the pre-compensation timing value. That is, UE 115-a may retain the pre-compensation timing value to itself and may utilize the pre-compensation timing value for uplink transmissions to adjust the timing advance indicated by base station 105-a.

[0111] For precompensation signaled by a UE 115-a or a base station 105-a (e.g., for both UE-side and network-side precompensation), two random access resources may be provided for one or more UEs 115 (e.g., capable UEs) (e.g., two different RACHConfigGenerics for each RACH attempt), wherein one random access resource may be configured with a precompensation timing value and one random access resource may be configured without a precompensation timing value (e.g., a fallback option). The random access resources may be provided in system information (e.g., broadcast to one or more UEs 115) or provided via dedicated RRC signaling. If the precompensation timing value is available at UE 115-b during the RACH attempt, UE 115-b may attempt to use a first random access resource that may include the precompensation timing value. If the RACH attempt fails, UE 115-b may use a second random access resource to perform random access without precompensation (e.g., a legacy state random access). For example, UE 115-a may send random access message 230 using a precompensation timing value via a second random access resource in the set of random access resources based on a precompensation timing value available to UE 115-a, and UE 115-a may send random access message 230 via a third random access resource in the set of random access resources based on a precompensation timing value not available to UE 115-a. In some examples, after monitoring the set of random access resources for random access message 230, base station 105-a may send a second message of a random access procedure indicating a timing precompensation of the random access message for UE 115-a to use for communication with base station 105-a.

[0112] In some examples, in a wireless communication system 200 (e.g., an NR wireless communication system), UE 115-a can indicate whether UE 115-a is capable of measuring its position (e.g., in x, y, and z coordinates), whether UE 115-a is capable of applying preamble timing precompensation to Msg1 (e.g., MsgA), or both. In an LTE wireless communication system, UE 115-a can indicate that UE 115-a is capable of measuring the altitude of UE 115-a and the x and y coordinates of UE 115-a.

[0113] Figure 3 An example of a wireless communication system 300 that supports random access to an over-the-air UE in a connected mode in accordance with aspects of the present disclosure is shown. In some examples, the wireless communication system 300 may implement aspects of the wireless communication systems 100 and 200, or may be implemented by aspects of the wireless communication systems 100 and 200. For example, the wireless communication system 300 may include a base station 105-b and a UE 115-b, which may be examples of corresponding devices described herein.

[0114] The wireless communication system 300 may implement techniques for improved random access for aerial UEs in RRC connected mode. For example, the wireless communication system 300 may support a RACH process between a base station 105-b and a UE 115-b, wherein the UE 115-b may be an aerial UE. In some examples, the UE 115-b may communicate with a satellite 305 via a communication link 310-a and communicate with a base station 105-b via a communication link 310-b, wherein the base station 105-b may be supported by a cell supporting aerial coverage. That is, the UE 115-b may be located in an aerial coverage area supported by the base station 105-b. In some examples, the UE 115-b may communicate with the satellite 305 for navigation purposes. For example, the UE 115-b may identify its location (e.g., x, y, and z coordinates) based on the communication between the UE 115-b and the satellite 305.

[0115] To prevent UE 115-b from sending a preamble (e.g., Msg1, MsgA) for a RACH procedure with a longer propagation delay (e.g., than a terrestrial UE), base station 105-b may send an indication of a pre-compensation timing value (e.g., t pre ) for UE 115-b to use for transmission of a random access message. The random access message may be part of a RACH procedure between the base station 105-b and the UE 115-b when the UE 115-b is in a connected mode, wherein the pre-compensation timing value may be based on the location of the UE 115-b. The UE 115-b may send the random access message using a set of random access resources associated with the pre-compensation timing value and the UE 115-b, and the base station 105-b may monitor the set of random access resources associated with the pre-compensation timing value and the UE 115-b to obtain the random access message.

[0116] Using the pre-compensated timing value, UE 115-b can send Msg1 at a time t earlier than the time t pre At 315, the base station 105-b may send a timing reference via a downlink frame, and at 320, the UE 115-b may receive a timing reference from the downlink frame. The downlink frame may take t1 time to reach the UE 115-b, where t1=d1 / c, d1 may represent the distance between the UE 115-b and the base station 105-b, and c may represent the speed of light. That is, due to the location of the UE 115-b, the downlink frame may be delayed by t1.

[0117] UE 115-b may use the pre-compensation timing value to align the transmission of the uplink random access preamble (e.g., Msg1) so that it can be transmitted t before the downlink frame timing. pre The transmission of the uplink random access preamble is scheduled in time units. At 325, UE 115-b may send the uplink random access preamble to base station 105-b with a delay t1 (e.g., propagation delay), and at 330, base station 105-b may receive the uplink random access preamble. In this way, the total round-trip delay between UE 115-b and base station 105-b between base station 105-b sending the timing reference and base station 105-b receiving the random access preamble (e.g., Msg1) may be reduced from 2t1 to 2t1-t2. pre .

[0118] Figure 4 An example of a process flow 400 for supporting random access to an over-the-air UE in connected mode according to aspects of the present disclosure is shown. The process flow 400 may implement aspects of the wireless communication system 100 and the wireless communication system 200, or may be implemented by aspects of the wireless communication system 100 and the wireless communication system 200. For example, the process flow 400 may illustrate operations between a base station 105-c and a UE 115-c, which may be examples of corresponding devices described herein. In the following description of the process flow 400, the operations between the base station 105-c and the UE 115-c may be sent in an order different from the example order shown, or the operations performed by the base station 105-c and the UE 115-c may be performed in a different order or at a different time. Some operations may also be omitted from the process flow 400, and other operations may be added to the process flow 400.

[0119] At 405, the base station 105-c may send a pre-compensated timing value (eg, t pre ). When the UE 115-c is in a connected mode (e.g., RRC_CONNECTED), the random access message may be part of a RACH procedure between the base station 105-c and the UE 115-c, wherein the pre-compensation timing value may be based on the location of the UE 115-c. For example, the UE 115-c may be located in an area (e.g., an air volume) supported by the base station 105-c, wherein the pre-compensation timing value may correspond to the area.

[0120] At 410, the base station 105-c may monitor a set of random access resources for a random access message based on the indication, the pre-compensation timing value, and the set of random access resources associated with the UE 115-c. In some examples, after monitoring the set of random access resources for the random access message, the base station 105-c may send a second message (e.g., Msg2) indicating a pre-compensated RACH procedure for the random access message for the UE 115-c for communication with the base station 105-c.

[0121] At 415, the UE 115-c may determine a precompensation timing value. In some cases, the UE 115-c may receive signaling indicating the location of the base station 105-c or signaling configuring a precompensation timing value offset to the UE 115-c. The UE 115-c may determine the precompensation timing value based on the location of the base station 105-c or the precompensation timing value offset. In some examples, the UE 115-c may determine the precompensation timing value based on the location of the base station 105-c and the location of the UE 115-c (e.g., x, y, and z coordinates).

[0122] At 420, UE 115-c may, based on receiving the indication of the precompensation timing value, send a random access message to base station 105-c using a first random access resource in a set of random access resources associated with the precompensation timing value and UE 115-c. In some examples, by sending the random access message using the precompensation timing value, UE 115-c may reduce an overall round-trip delay when sending the random access message to base station 105-c.

[0123] Figure 5 A block diagram 500 of a device 505 supporting random access to an over-the-air UE in connected mode according to aspects of the present disclosure is shown. The device 505 may be an example of aspects of a base station 105 as described herein. The device 505 may include a receiver 510, a transmitter 515, and a communication manager 520. The device 505 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0124] The receiver 510 may provide a means for receiving information, such as packets, user data, control information, or any combination of information associated with various information channels (e.g., control channels, data channels, information channels related to random access of airborne UEs in connected mode). The information may be delivered to other components of the device 505. The receiver 510 may utilize a single antenna or a collection of multiple antennas.

[0125] The transmitter 515 may provide a means for transmitting signals generated by other components of the device 505. For example, the transmitter 515 may transmit any combination of information associated with various information channels (e.g., control channels, data channels, information channels related to random access of airborne UEs in connected mode). In some examples, the transmitter 515 may be co-located with the receiver 510 in a transceiver module. The transmitter 515 may utilize a single antenna or a collection of multiple antennas.

[0126] The communication manager 520, the receiver 510, the transmitter 515, or various combinations thereof, or various components thereof may be examples of means for performing various aspects of random access for an over-the-air UE in connected mode, as described herein. For example, the communication manager 520, the receiver 510, the transmitter 515, or various combinations thereof, or components thereof may support methods for performing one or more of the functions described herein.

[0127] In some examples, the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof can be implemented in hardware (e.g., in a communication management circuit system). The hardware can include a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, configured as or otherwise supporting means for performing the functions described in the present disclosure. In some examples, a processor and a memory coupled to the processor can be configured to perform one or more of the functions described herein (e.g., by executing instructions stored in the memory by the processor).

[0128] Additionally or alternatively, in some examples, the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functions of the communication manager 520, the receiver 510, the transmitter 515, or various combinations or components thereof may be performed by a general purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination of these components or other programmable logic devices (e.g., configured as or otherwise supporting a unit for performing the functions described in the present disclosure).

[0129] In some examples, communication manager 520 can be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with receiver 510, transmitter 515, or both. For example, communication manager 520 can receive information from receiver 510, send information to transmitter 515, or be integrated with receiver 510, transmitter 515, or both to receive information, send information, or perform various other operations as described herein.

[0130] According to examples as disclosed herein, the communication manager 520 may support wireless communications at a base station. For example, the communication manager 520 may be configured to or otherwise support a unit for sending an indication of a pre-compensation timing value for use in transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The communication manager 520 may be configured to or otherwise support a unit for monitoring a set of random access resources for the random access message based on the indication, the set of random access resources being associated with the pre-compensation timing value and the airborne UE.

[0131] By including or configuring the communication manager 520 according to the examples described herein, the device 505 (e.g., a processor controlling or otherwise coupled to the receiver 510, the transmitter 515, the communication manager 520, or a combination thereof) can support techniques for improving RACH procedures for airborne UEs in a connected state. For example, in some cases, the described techniques can enable the UE to send random access messages associated with the RACH procedure with reduced propagation delay, which can reduce latency and improve user experience.

[0132] Figure 6 A block diagram 600 of a device 605 supporting random access to an over-the-air UE in connected mode according to aspects of the present disclosure is shown. The device 605 may be an example of aspects of the device 505 or base station 105 as described herein. The device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. The device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0133] The receiver 610 may provide a means for receiving information, such as packets, user data, control information, or any combination of information associated with various information channels (e.g., control channels, data channels, information channels related to random access of airborne UEs in connected mode). The information may be delivered to other components of the device 605. The receiver 610 may utilize a single antenna or a collection of multiple antennas.

[0134] The transmitter 615 may provide a means for transmitting signals generated by other components of the device 605. For example, the transmitter 615 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels associated with random access of airborne UEs in connected mode). In some examples, the transmitter 615 may be located in a transceiver module with the receiver 610. The transmitter 615 may utilize a single antenna or a collection of multiple antennas.

[0135] The device 605 or its various components may be examples of units for performing various aspects of random access to an airborne UE in connected mode as described herein. For example, the communication manager 620 may include an indication transmission component 625, a monitoring component 630, or any combination thereof. The communication manager 620 may be an example of various aspects of the communication manager 520 as described herein. In some examples, the communication manager 620 or its various components may be configured to perform various operations (e.g., receive, monitor, send) using the receiver 610, the transmitter 615, or both or otherwise cooperate with the receiver 610, the transmitter 615, or both. For example, the communication manager 620 may receive information from the receiver 610, send information to the transmitter 615, or be integrated with the receiver 610, the transmitter 615, or both to receive information, send information, or perform various other operations as described herein.

[0136] According to examples as disclosed herein, the communication manager 620 can support wireless communications at a base station. The indication transmission component 625 can be configured to or otherwise support means for transmitting an indication of a pre-compensation timing value for use in transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The monitoring component 630 can be configured to or otherwise support means for monitoring a set of random access resources for the random access message based on the indication, the set of random access resources being associated with the pre-compensation timing value and the airborne UE.

[0137] Figure 7A block diagram 700 of a communication manager 720 supporting random access to an airborne UE in connected mode in accordance with various aspects of the present disclosure is shown. The communication manager 720 may be an example of aspects of the communication manager 520, the communication manager 620, or both as described herein. The communication manager 720 or its various components may be examples of units for performing various aspects of random access to an airborne UE in connected mode as described herein. For example, the communication manager 720 may include an indication transmission component 725, a monitoring component 730, a regional signaling component 735, a capability reception component 740, a random access component 745, a report reception component 750, or any combination thereof. Each of these components may communicate with each other directly or indirectly (e.g., via one or more buses).

[0138] According to examples disclosed herein, a communication manager 720 can support wireless communications at a base station. An indication transmission component 725 can be configured to or otherwise support means for transmitting an indication of a pre-compensation timing value for use in transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. A monitoring component 730 can be configured to or otherwise support means for monitoring a set of random access resources for the random access message based on the indication, the set of random access resources being associated with the pre-compensation timing value and the airborne UE.

[0139] In some examples, to support sending an indication of a pre-compensation timing value, the indication transmission component 725 can be configured as or otherwise support a unit for sending an indication of a pre-compensation timing value for transmitting a random access message by an airborne UE, when the airborne UE is in a connected state, the random access message being part of a random access procedure between a base station and the airborne UE.

[0140] In some examples, to support sending an indication of a pre-compensation timing value, the indication transmission component 725 can be configured as or otherwise support a unit for sending an indication of a pre-compensation timing value to an airborne UE via RRC signaling, MAC-CE, or DCI, wherein the pre-compensation timing value is specific to the airborne UE.

[0141] In some examples, to support sending an indication of a pre-compensation timing value, the indication transmission component 725 can be configured or otherwise support means for sending an index corresponding to a pre-compensation timing value for transmitting a random access message by an over-the-air UE.

[0142] In some examples, to support sending an indication of a pre-compensation timing value, the regional signaling component 735 can be configured as or otherwise support a unit for sending broadcast signaling indicating a set of multiple regions and corresponding region identifiers, wherein each region in the set of multiple regions is associated with a corresponding pre-compensation timing value for transmitting a random access message by an over-the-air UE.

[0143] In some examples, the regional signaling component 735 can be configured as or otherwise support means for sending an indication to activate a regional identifier for the airborne UE via a dedicated RRC message.

[0144] In some examples, the region signaling component 735 can be configured as or otherwise support means for sending a bitmap to an air UE via a MAC-CE or DCI to activate a region identifier for the air UE.

[0145] In some examples, the regional signaling component 735 can be configured to or otherwise support a unit for maintaining a list that includes a set of multiple regions based on one or more measurements associated with one or more aerial UEs and corresponding precompensation timing values. In some examples, each precompensation timing value corresponds to a minimum value of precompensation for a corresponding region of a random access preamble transmission.

[0146] In some examples, capability receiving component 740 can be configured as or otherwise support means for receiving a capability message from an airborne UE indicating the ability of the airborne UE to measure the position of the airborne UE, apply a pre-compensation timing value, or both.

[0147] In some examples, the random access component 745 can be configured to or otherwise support means for sending a second message of the random access procedure after monitoring a set of random access resources for a random access message, the second message indicating a timing pre-compensation of the random access message.

[0148] In some examples, to support sending an indication of a pre-compensation timing value, the indication transmission component 725 can be configured as or otherwise support a unit for sending signaling indicating the location of the base station via system information or dedicated RRC signaling.

[0149] In some examples, to support sending an indication of a pre-compensation timing value, the indication transmission component 725 can be configured as or otherwise support a means for sending signaling to configure a pre-compensation timing value offset to an over-the-air UE.

[0150] In some examples, report receiving component 750 may be configured or otherwise support means for receiving a report indicating a pre-compensation timing value determined or used by an over-the-air UE based on completion of a random access procedure.

[0151] Figure 8 A diagram of a system 800 including a device 805 supporting random access to an airborne UE in connected mode in accordance with various aspects of the present disclosure is shown. The device 805 may be an example of a device 505, a device 605, or a base station 105 as described herein or include components thereof. The device 805 may wirelessly communicate with one or more base stations 105, UEs 115, or any combination thereof. The device 805 may include components for two-way voice and data communications, including components for sending and receiving communications, such as a communication manager 820, a network communication manager 810, a transceiver 815, an antenna 825, a memory 830, a code 835, a processor 840, and an inter-station communication manager 845. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 850).

[0152] The network communications manager 810 may manage communications with the core network 130 (eg, via one or more wired backhaul links). For example, the network communications manager 810 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0153] In some cases, the device 805 may include a single antenna 825. However, in some other cases, the device 805 may have more than one antenna 825, which can send or receive multiple wireless transmissions at the same time. The transceiver 815 can communicate bidirectionally via one or more antennas 825, wired or wireless links as described herein. For example, the transceiver 815 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 815 can also include a modem for modulating packets, providing the modulated packets to one or more antennas 825 for transmission, and demodulating packets received from one or more antennas 825. The transceiver 815, or the transceiver 815 and the one or more antennas 825 as described herein can be examples of transmitters 515, transmitters 615, receivers 510, receivers 610, or any combination thereof or components thereof.

[0154] The memory 830 may include random access memory (RAM) and read-only memory (ROM). The memory 830 may store computer-readable, computer-executable code 835 including instructions, which, when executed by the processor 840, causes the device 805 to perform various functions described herein. The code 835 may be stored in a non-temporary computer-readable medium, such as a system memory or another type of memory. In some cases, the code 835 may not be directly executed by the processor 840, but may cause the computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, the memory 830 may include a basic I / O system (BIOS) and other components, and the BIOS may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0155] The processor 840 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., a memory 830) so that the device 805 performs various functions (e.g., functions or tasks that support random access to an air UE in a connected mode). For example, the device 805 or a component of the device 805 may include a processor 840 and a memory 830 coupled to the processor 840, and the processor 840 and the memory 830 are configured to perform various functions described herein.

[0156] The inter-site communication manager 845 can manage communications with other base stations 105 and can include a controller or scheduler for coordinating with other base stations 105 to control communications with UE 115. For example, the inter-site communication manager 845 can coordinate scheduling for transmissions to UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-site communication manager 845 can provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0157] According to examples as disclosed herein, the communication manager 820 may support wireless communications at a base station. For example, the communication manager 820 may be configured to or otherwise support a unit for sending an indication of a pre-compensation timing value for use in transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The communication manager 820 may be configured to or otherwise support a unit for monitoring a set of random access resources for the random access message based on the indication, the set of random access resources being associated with the pre-compensation timing value and the airborne UE.

[0158] According to examples as described herein, the device 805 may support techniques for an improved RACH procedure for an over-the-air UE in a connected state by including or configuring the communication manager 820. For example, in some cases, the described techniques may enable the UE to send a random access message associated with the RACH procedure with reduced propagation delay, which may reduce latency and improve user experience.

[0159] In some examples, the communication manager 820 can be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the transceiver 815, one or more antennas 825, or any combination thereof. Although the communication manager 820 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 820 can be supported or performed by the processor 840, the memory 830, the code 835, or any combination thereof. For example, the code 835 can include instructions executable by the processor 840 to cause the device 805 to perform various aspects of random access for an airborne UE in connected mode as described herein, or the processor 840 and the memory 830 can be otherwise configured to perform or support such operations.

[0160] Fig. 9 A block diagram 900 of a device 905 supporting random access to an over-the-air UE in connected mode according to aspects of the present disclosure is shown. The device 905 may be an example of aspects of a UE 115 as described herein. The device 905 may include a receiver 910, a transmitter 915, and a communication manager 920. The device 905 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0161] The receiver 910 may provide a means for receiving information, such as packets, user data, control information, or any combination of information associated with various information channels (e.g., control channels, data channels, information channels related to random access of airborne UEs in connected mode). The information may be delivered to other components of the device 905. The receiver 910 may utilize a single antenna or a collection of multiple antennas.

[0162] The transmitter 915 may provide a means for transmitting signals generated by other components of the device 905. For example, the transmitter 915 may transmit various information channels (e.g., control channels, data channels, information channels related to random access of airborne UEs in connected mode). In some examples, the transmitter 915 may be co-located with the receiver 910 in a transceiver module. The transmitter 915 may utilize a single antenna or a collection of multiple antennas.

[0163] The communication manager 920, the receiver 910, the transmitter 915, or various combinations thereof, or various components thereof may be examples of means for performing various aspects of random access for an over-the-air UE in connected mode as described herein. For example, the communication manager 920, the receiver 910, the transmitter 915, or various combinations thereof, or components thereof may support methods for performing one or more of the functions described herein.

[0164] In some examples, the communication manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof can be implemented in hardware (e.g., in a communication management circuit system). The hardware can include a processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, which is configured as or otherwise supports a unit for performing the functions described in the present disclosure. In some examples, a processor and a memory coupled to the processor can be configured to perform one or more of the functions described herein (e.g., by executing instructions stored in the memory by the processor).

[0165] Additionally or alternatively, in some examples, the communication manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functionality of the communication manager 920, the receiver 910, the transmitter 915, or various combinations or components thereof may be implemented by a general purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a unit for performing the functionality described in the present disclosure).

[0166] In some examples, the communication manager 920 can be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the receiver 910, the transmitter 915, or both. For example, the communication manager 920 can receive information from the receiver 910, send information to the transmitter 915, or be integrated in conjunction with the receiver 910, the transmitter 915, or both to receive information, send information, or perform various other operations as described herein.

[0167] According to examples disclosed herein, the communication manager 920 may support wireless communications at an airborne UE. For example, the communication manager 920 may be configured to or otherwise support a unit for receiving an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE. The communication manager 920 may be configured to or otherwise support a unit for sending a random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE based on the received indication.

[0168] By including or configuring the communication manager 920 according to examples as described herein, the device 905 (e.g., a processor controlling or otherwise coupled to the receiver 910, the transmitter 915, the communication manager 920, or a combination thereof) can support techniques for improving RACH procedures for airborne UEs in a connected state. For example, in some cases, the described techniques can enable the UE to send random access messages associated with the RACH procedure with reduced propagation delay, which can reduce latency and improve user experience.

[0169] Fig.10 A block diagram 1000 of a device 1005 supporting random access to an over-the-air UE in connected mode in accordance with aspects of the present disclosure is shown. The device 1005 may be an example of aspects of the device 905 or UE 115 as described herein. The device 1005 may include a receiver 1010, a transmitter 1015, and a communication manager 1020. The device 1005 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0170] The receiver 1010 may provide a means for receiving information, such as packets, user data, control information, or any combination of information associated with various information channels (e.g., control channels, data channels, information channels related to random access of airborne UEs in connected mode). The information may be delivered to other components of the device 1005. The receiver 1010 may utilize a single antenna or a collection of multiple antennas.

[0171] The transmitter 1015 may provide a means for transmitting signals generated by other components of the device 1005. For example, the transmitter 1015 may transmit various information channels (e.g., control channels, data channels, information channels related to random access of UEs in connected mode). In some examples, the transmitter 1015 may be co-located with the receiver 1010 in a transceiver module. The transmitter 1015 may utilize a single antenna or a collection of multiple antennas.

[0172] The device 1005 or its various components may be examples of units for performing various aspects of random access to an airborne UE in connected mode as described herein. For example, the communication manager 1020 may include an indication receiving component 1025, a random access message component 1030, or any combination thereof. The communication manager 1020 may be an example of various aspects of the communication manager 920 as described herein. In some examples, the communication manager 1020 or its various components may be configured to perform various operations (e.g., receive, monitor, send) using the receiver 1010, the transmitter 1015, or both, or otherwise cooperate with the receiver 1010, the transmitter 1015, or both. For example, the communication manager 1020 may receive information from the receiver 1010, send information to the transmitter 1015, or be integrated with the receiver 1010, the transmitter 1015, or both to receive information, send information, or perform various other operations as described herein.

[0173] According to examples disclosed herein, a communication manager 1020 can support wireless communications at an airborne UE. An indication receiving component 1025 can be configured or otherwise support means for receiving an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE. A random access message component 1030 can be configured or otherwise support means for sending a random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE based on the received indication.

[0174] Fig.11A block diagram 1100 of a communication manager 1120 supporting random access to an airborne UE in connected mode in accordance with aspects of the present disclosure is shown. The communication manager 1120 may be an example of aspects of the communication manager 920, the communication manager 1020, or both as described herein. The communication manager 1120 or its various components may be an example of a means for performing various aspects of random access to an airborne UE in connected mode as described herein. For example, the communication manager 1120 may include an indication receiving component 1125, a random access message component 1130, a timing value determining component 1135, a report transmission component 1140, a random access message component 1145, a capability transmission component 1150, an index receiving component 1155, a region component 1160, or any combination thereof. Each of these components may communicate with each other directly or indirectly (e.g., via one or more buses).

[0175] According to examples disclosed herein, a communication manager 1120 can support wireless communications at an airborne UE. An indication receiving component 1125 can be configured or otherwise support means for receiving an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE. A random access message component 1130 can be configured or otherwise support means for sending a random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE based on the received indication.

[0176] In some examples, to support receiving an indication of a pre-compensation timing value, the indication receiving component 1125 can be configured as or otherwise support a unit for receiving an indication of a pre-compensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE when the airborne UE is in a connected state.

[0177] In some examples, to support receiving an indication of a precompensation timing value, indication receiving component 1125 can be configured as or otherwise support means for receiving signaling indicating a location of a base station via system information or dedicated RRC signaling. In some examples, to support receiving an indication of a precompensation timing value, timing value determining component 1135 can be configured as or otherwise support means for determining a precompensation timing value based on the location of the base station.

[0178] In some examples, to support receiving an indication of a precompensation timing value, the indication receiving component 1125 can be configured as or otherwise support means for receiving signaling to configure a precompensation timing value offset to an over-the-air UE. In some examples, to support receiving an indication of a precompensation timing value, the timing value determining component 1135 can be configured as or otherwise support means for determining a precompensation timing value based on the precompensation timing value offset.

[0179] In some examples, timing value determination component 1135 can be configured as or otherwise support means for determining a pre-compensation timing value based on a location of a base station and a location of an aerial UE.

[0180] In some examples, report transmission component 1140 can be configured as or otherwise support means for transmitting a report indicating a pre-compensation timing value determined by the UE over the air based on completion of a random access procedure.

[0181] In some examples, the random access message component 1145 can be configured or otherwise support means for sending a random access message using a precompensation timing value via a second random access resource in a set of random access resources based on the precompensation timing value being available at the UE over the air. In some examples, the random access message component 1145 can be configured or otherwise support means for sending a random access message via a third random access resource in a set of random access resources based on a precompensation timing value that is not available at the UE over the air.

[0182] In some examples, the capability transmission component 1150 can be configured as or otherwise support means for transmitting a capability message from an airborne UE indicating the ability of the airborne UE to measure the position of the airborne UE, apply a pre-compensation timing value, or both.

[0183] In some examples, to support receiving an indication of a pre-compensation timing value, the indication receiving component 1125 can be configured as or otherwise support a unit for receiving an indication of a pre-compensation timing value from a base station via RRC signaling, MAC-CE, or DCI, wherein the pre-compensation timing value is specific to an airborne UE.

[0184] In some examples, to support receiving an indication of a pre-compensation timing value, index receiving component 1155 may be configured as or otherwise support means for receiving an index corresponding to a pre-compensation timing value for transmitting a random access message by an over-the-air UE.

[0185] In some examples, to support receiving an indication of a pre-compensation timing value, the regional component 1160 can be configured as or otherwise support a unit for receiving broadcast signaling indicating a set of multiple regions and corresponding region identifiers, wherein each region in the set of multiple regions is associated with a corresponding pre-compensation timing value for transmitting a random access message by an over-the-air UE.

[0186] In some examples, the regional component 1160 can be configured as or otherwise support means for receiving an indication to activate a regional identifier for airborne UEs from a base station via a dedicated RRC message.

[0187] In some examples, the zone component 1160 can be configured as or otherwise support means for receiving a bitmap from a base station via a MAC-CE or DCI to activate a zone identifier for an airborne UE. In some examples, each precompensation timing value corresponds to a minimum value of precompensation for a corresponding zone of a random access preamble transmission.

[0188] In some examples, the random access message component 1145 can be configured to or otherwise support a unit for receiving a second message for a random access procedure after sending a random access message, the second message indicating a timing pre-compensation for the random access message.

[0189] Fig.12 A diagram of a system 1200 including a device 1205 supporting random access to an airborne UE in connected mode according to various aspects of the present disclosure is shown. The device 1205 may be an example of a device 905, a device 1005, or a UE 115 as described herein or include a component of the device 905, the device 1005, or a UE 115. The device 1205 may communicate wirelessly with one or more base stations 105, UE 115, or any combination thereof. The device 1205 may include components for two-way voice and data communications, including components for sending and receiving communications, such as a communication manager 1220, an input / output (I / O) controller 1210, a transceiver 1215, an antenna 1225, a memory 1230, a code 1235, and a processor 1240. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 1245).

[0190] I / O controller 1210 can manage input and output signals for device 1205. I / O controller 1210 can also manage peripheral devices that are not integrated into device 1205. In some cases, I / O controller 1210 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 1210 can utilize an operating system, such as Or another known operating system. Additionally or alternatively, I / O controller 1210 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 1210 may be implemented as part of a processor (e.g., processor 1240). In some cases, a user may interact with device 1205 via I / O controller 1210 or via hardware components controlled by I / O controller 1210.

[0191] In some cases, the device 1205 may include a single antenna 1225. However, in some other cases, the device 1205 may have more than one antenna 1225, which can send or receive multiple wireless transmissions simultaneously. The transceiver 1215 can communicate bidirectionally via one or more antennas 1225, wired or wireless links as described herein. For example, the transceiver 1215 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 1215 may also include a modem to modulate packets, provide the modulated packets to one or more antennas 1225 for transmission, and demodulate packets received from one or more antennas 1225. The transceiver 1215, or the transceiver 1215 and the one or more antennas 1225 can be examples of transmitters 915, transmitters 1015, receivers 910, receivers 1010, or any combination thereof or components thereof, as described herein.

[0192] Memory 1230 may include RAM and ROM. Memory 1230 may store computer-readable, computer-executable code 1235 including instructions that, when executed by processor 1240, cause device 1205 to perform various functions described herein. Code 1235 may be stored in a non-temporary computer-readable medium, such as system memory or another type of memory. In some cases, code 1235 may not be directly executable by processor 1240, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, memory 1230 may include BIOS and other components, and BIOS may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0193] The processor 1240 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 1240 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 1240. The processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., a memory 1230) so that the device 1205 performs various functions (e.g., functions or tasks that support random access to an air UE in a connected mode). For example, the device 1205 or a component of the device 1205 may include a processor 1240 and a memory 1230 coupled to the processor 1240, and the processor 1240 and the memory 1230 are configured to perform various functions described herein.

[0194] According to examples disclosed herein, the communication manager 1220 may support wireless communications at an airborne UE. For example, the communication manager 1220 may be configured to or otherwise support a unit for receiving an indication of a precompensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the precompensation timing value is based on a location of the airborne UE. The communication manager 1220 may be configured to or otherwise support a unit for sending a random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE based on the received indication.

[0195] According to examples described herein, device 1205 may support techniques for an improved RACH procedure for connected over-the-air UEs by including or configuring the communication manager 1220. For example, in some cases, the described techniques may enable a UE to send a random access message associated with a RACH procedure with reduced propagation delay, which may reduce latency and improve user experience.

[0196] In some examples, the communication manager 1220 can be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the transceiver 1215, one or more antennas 1225, or any combination thereof. Although the communication manager 1220 is shown as a separate component, in some examples, one or more functions described with reference to the communication manager 1220 can be supported or performed by the processor 1240, the memory 1230, the code 1235, or any combination thereof. For example, the code 1235 can include instructions executable by the processor 1240 to cause the device 1205 to perform various aspects of random access to an airborne UE in connected mode, as described herein, or the processor 1240 and the memory 1230 can be otherwise configured to perform or support such operations.

[0197] Fig.13 A flow chart illustrating a method 1300 for supporting random access to an airborne UE in connected mode according to aspects of the present disclosure is shown. The operations of the method 1300 may be implemented by a base station or components thereof as described herein. For example, the operations of the method 1300 may be performed by the base station 105, as described with reference to Figures 1 to 8 In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the described functions.

[0198] At 1305, the method may include sending an indication of a pre-compensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The operations of 1305 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1305 may be performed as described in reference to Figure 7 The described instructions are executed by the transmission component 725.

[0199] At 1310, the method may include monitoring a set of random access resources for a random access message based on the indication, the set of random access resources being associated with a pre-compensation timing value and an airborne UE. The operations of 1310 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1310 may be performed as described in reference to Figure 7 The described monitoring component 730 is performed.

[0200] Fig.14A flowchart of a method 1400 for supporting random access to an airborne UE in a connected mode is shown according to various aspects of the present disclosure. The operations of the method 1400 may be implemented by a base station or a component thereof as described herein. For example, the operations of the method 1400 may be performed by the base station 105, as described in reference to Figures 1 to 8 In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform various aspects of the described functions.

[0201] At 1405, the method may include sending an indication of a pre-compensation timing value for transmitting a random access message by the airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE when the airborne UE is in a connected state, wherein the pre-compensation timing value is based on a location of the airborne UE. The operations of 1405 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1405 may be performed as described in reference to Figure 7 The described instructions are executed by the transmission component 725.

[0202] At 1410, the method may include sending broadcast signaling indicating a set of multiple regions and corresponding region identifiers, wherein each region in the set of multiple regions is associated with a corresponding pre-compensation timing value for transmitting a random access message by an airborne UE. The operations of 1410 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1410 may be performed as described in reference to Figure 7 The described regional signaling component 735 is performed.

[0203] At 1415, the method may include monitoring a set of random access resources for random access messages based on the indication, the set of random access resources being associated with the pre-compensation timing value and the airborne UE. The operations of 1415 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1415 may be performed as described in reference to Figure 7 The described monitoring component 730 is performed.

[0204] Fig.15 A flow chart of a method 1500 for supporting random access to an airborne UE in connected mode is shown according to various aspects of the present disclosure. The operations of the method 1500 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1500 may be performed by a UE 115, as described in reference to Figures 1 to 4 as well as Figures 9 to 12In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the described functions.

[0205] At 1505, the method may include receiving an indication of a pre-compensation timing value for a random access message transmitted by an airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The operations of 1505 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1505 may be performed by reference to Fig.11 The described instructions are received by component 1125 for execution.

[0206] At 1510, the method may include, based on receiving the indication, sending a random access message using a first random access resource in a set of random access resources associated with a pre-compensation timing value and an airborne UE. The operations of 1510 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1510 may be described with reference to Fig.11 The random access message component 1130 described above is performed.

[0207] Fig.16 A flowchart of a method 1600 for supporting random access to an airborne UE in connected mode is shown according to aspects of the present disclosure. The operations of the method 1600 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1600 may be performed by a UE 115, as described in reference to Figures 1 to 4 as well as Figures 9 to 12 In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the described functions.

[0208] At 1605, the method may include receiving an indication of a pre-compensation timing value for a random access message transmitted by an airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The operations of 1605 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1605 may be performed by reference to Fig.11 The described instructions are received by component 1125 for execution.

[0209] At 1610, the method may include receiving signaling indicating the location of the base station via system information or dedicated RRC signaling. The operations of 1610 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1610 may be described with reference to Fig.11 The described instructions are received by component 1125 for execution.

[0210] At 1615, the method may include determining a precompensation timing value based on the location of the base station. The operations of 1615 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1615 may be performed as described in reference to Fig.11 The described timing value determination component 1135 is executed.

[0211] At 1620, the method may include, based on receiving the indication, sending a random access message using a first random access resource in a set of random access resources associated with the pre-compensation timing value and the airborne UE. The operations of 1620 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1620 may be performed as described in reference to Fig.11 The random access message component 1130 described above is performed.

[0212] Fig.17 A flowchart of a method 1700 for supporting random access to an airborne UE in connected mode is shown according to various aspects of the present disclosure. The operations of the method 1700 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1700 may be performed by a UE 115, as described in reference to Figures 1 to 4 as well as Figures 9 to 12 In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the described functions.

[0213] At 1705, the method may include receiving an indication of a pre-compensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between a base station and the airborne UE, wherein the pre-compensation timing value is based on a location of the airborne UE. The operations of 1705 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1705 may be performed as described in reference to Fig.11 The described instructions are received by component 1125 for execution.

[0214] At 1710, the method may include sending a random access message using a precompensated timing value via a second random access resource in a set of random access resources based on a precompensated timing value available at the UE in the air. The operations of 1710 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1710 may be performed as described in reference to Fig.11 The random access message component 1145 described above is performed.

[0215] At 1715, the method may include sending a random access message via a third random access resource in the set of random access resources based on a pre-compensated timing value that is not available at the UE in the air. The operations of 1715 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1715 may be performed as described in reference to Fig.11 The random access message component 1145 described above is performed.

[0216] A summary of various aspects of the disclosure is provided below:

[0217] Aspect 1: A method for wireless communication at a base station, comprising: sending an indication of a pre-compensation timing value for transmitting a random access message by an airborne UE, the random access message being part of a random access procedure between the base station and the airborne UE, wherein the pre-compensation timing value is based at least in part on a location of the airborne UE; and monitoring a set of random access resources for the random access message based at least in part on the indication, the set of random access resources being associated with the pre-compensation timing value and the airborne UE.

[0218] Aspect 2: A method according to Aspect 1, wherein sending an indication of a pre-compensation timing value includes: sending an indication of a pre-compensation timing value used to transmit a random access message by an airborne UE, when the airborne UE is in a connected state, the random access message is part of a random access procedure between a base station and the airborne UE.

[0219] Aspect 3: According to the method according to any one of Aspects 1 to 2, sending an indication of a pre-compensation timing value includes: sending an indication of a pre-compensation timing value to an airborne UE via RRC signaling, MAC-CE or DCI, wherein the pre-compensation timing value is specific to the airborne UE.

[0220] Aspect 4: The method according to any one of aspects 1 to 3, wherein sending an indication of a pre-compensation timing value comprises sending an index corresponding to a pre-compensation timing value used for transmitting a random access message by an over-the-air UE.

[0221] Aspect 5: A method according to any one of Aspects 1 to 4, wherein sending an indication of a pre-compensation timing value includes: sending broadcast signaling indicating multiple areas and corresponding area identifiers, wherein each area in the multiple areas is associated with a corresponding pre-compensation timing value for transmitting a random access message by an airborne UE.

[0222] Aspect 6: The method according to aspect 5 further includes: sending an indication of activating the area identifier for the airborne UE to the airborne UE via a dedicated RRC message.

[0223] Aspect 7: The method according to any one of aspects 5 to 6 further includes: sending a bitmap to the air UE via MAC-CE or DCI to activate the area identifier for the air UE.

[0224] Aspect 8: The method according to any one of aspects 5 to 7 further includes: maintaining a list including multiple regions and corresponding pre-compensation timing values ​​based at least in part on one or more measurements associated with one or more aerial UEs.

[0225] Aspect 9: The method according to any one of aspects 5 to 8, wherein each precompensation timing value corresponds to a minimum value of precompensation for a corresponding zone of random access preamble transmission.

[0226] Aspect 10: The method according to any one of aspects 1 to 9 further includes: receiving a capability message from the airborne UE, the capability message indicating the capability of the airborne UE to measure the position of the airborne UE, apply the pre-compensation timing value, or both.

[0227] Aspect 11: The method according to any one of Aspects 1 to 10 further includes: sending a second message of a random access procedure after monitoring a set of random access resources of a random access message, the second message indicating a timing pre-compensation of the random access message.

[0228] Aspect 12: The method according to any one of aspects 1 to 11, wherein sending an indication of the pre-compensation timing value includes: sending signaling indicating the location of the base station via system information or dedicated RRC signaling.

[0229] Aspect 13: The method according to any one of aspects 1 to 12, wherein sending an indication of a pre-compensation timing value comprises: sending signaling to configure an offset of a pre-compensation timing value to an over-the-air UE.

[0230] Aspect 14: The method according to any one of aspects 1 to 13 further includes: receiving a report indicating a pre-compensation timing value determined or used by the UE in the air based at least in part on the completion of the random access procedure.

[0231] Aspect 15: A method for wireless communication at an aerial UE, comprising: receiving an indication of a pre-compensation timing value for transmitting a random access message by the aerial UE, the random access message being part of a random access procedure between a base station and the aerial UE, wherein the pre-compensation timing value is based at least in part on a location of the aerial UE; and sending the random access message using a first random access resource in a set of random access resources associated with the pre-compensation timing value and the aerial UE based at least in part on receiving the indication.

[0232] Aspect 16: A method according to Aspect 15, wherein receiving an indication of a pre-compensation timing value includes: receiving an indication of a pre-compensation timing value used to transmit a random access message by an airborne UE, when the airborne UE is in a connected state, the random access message is part of a random access procedure between a base station and the airborne UE.

[0233] Aspect 17: A method according to any one of Aspects 15 to 16, wherein receiving an indication of a pre-compensation timing value comprises: receiving signaling indicating the location of a base station via system information or dedicated RRC signaling; and determining the pre-compensation timing value based at least in part on the location of the base station.

[0234] Aspect 18: A method according to any one of Aspects 15 to 17, wherein receiving an indication of a precompensation timing value includes: receiving signaling to configure a precompensation timing value offset to an airborne UE; and determining the precompensation timing value based at least in part on the precompensation timing value offset.

[0235] Aspect 19: The method according to any one of aspects 15 to 18 further includes: determining the pre-compensation timing value based at least in part on the location of the base station and the location of the UE in the air.

[0236] Aspect 20: The method according to any one of aspects 15 to 19, further comprising: sending a report indicating the pre-compensation timing value determined by the UE over the air based at least in part on the completion of the random access procedure.

[0237] Aspect 21: The method according to any one of Aspects 15 to 20 further includes: sending a random access message using the pre-compensation timing value via a second random access resource in a set of random access resources, based at least in part on the pre-compensation timing value being available at the UE in the air; and sending a random access message via a third random access resource in the set of random access resources, based at least in part on the pre-compensation timing value being unavailable at the UE in the air.

[0238] Aspect 22: The method according to any one of aspects 15 to 21 further includes: sending a capability message from the airborne UE, the capability message indicating the capability of the airborne UE to measure the position of the airborne UE, apply the pre-compensation timing value, or both.

[0239] Aspect 23: A method according to any one of Aspects 15 to 22, wherein receiving an indication of a pre-compensation timing value comprises: receiving an indication of a pre-compensation timing value from a base station via RRC signaling, MAC-CE or DCI, wherein the pre-compensation timing value is specific to an airborne UE.

[0240] Aspect 24: The method according to any one of aspects 15 to 23, wherein receiving an indication of a pre-compensation timing value comprises: receiving an index corresponding to a pre-compensation timing value used for transmitting a random access message by the UE over the air.

[0241] Aspect 25: A method according to any one of Aspects 15 to 24, wherein receiving an indication of a pre-compensation timing value includes: receiving broadcast signaling indicating multiple areas and corresponding area identifiers, wherein each area in the multiple areas is associated with a corresponding pre-compensation timing value for transmitting a random access message by an airborne UE.

[0242] Aspect 26: The method according to aspect 25 further includes: receiving an indication to activate the area identifier for the air UE from the base station via a dedicated RRC message.

[0243] Aspect 27: The method according to any one of aspects 25 to 26 further includes: receiving a bitmap from a base station via MAC-CE or DCI to activate a region identifier for an airborne UE.

[0244] Aspect 28: A method according to any one of aspects 25 to 27, wherein each precompensation timing value corresponds to a minimum value of precompensation for a corresponding zone of random access preamble transmission.

[0245] Aspect 29: The method according to any one of Aspects 15 to 28 further includes: receiving a second message of a random access procedure after sending the random access message, the second message indicating a timing pre-compensation of the random access message.

[0246] Aspect 30: An apparatus for wireless communication at a base station, comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of Aspects 1 to 14.

[0247] Aspect 31: An apparatus for wireless communication at a base station, comprising at least one unit for performing the method of any one of Aspects 1 to 14.

[0248] Aspect 32: A non-transitory computer-readable medium storing a code for wireless communication at a base station, the code comprising instructions executable by a processor to perform the method of any one of aspects 1 to 14.

[0249] Aspect 33: An apparatus for wireless communication at an airborne UE, comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of Aspects 15 to 29.

[0250] Aspect 34: An apparatus for wireless communication at an airborne UE, comprising at least one unit for executing the method of any one of aspects 15 to 29.

[0251] Aspect 35: A non-transitory computer-readable medium storing a code for wireless communication at an airborne UE, the code comprising instructions executable by a processor to perform the method of any one of aspects 15 to 29.

[0252] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0253] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0254] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0255] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed with a general purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components designed to perform the functions described herein, or any combination thereof. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors with a DSP core, or any other such configuration).

[0256] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on a computer-readable medium or sent as one or more instructions or codes on a computer-readable medium. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented in different physical locations.

[0257] Computer-readable media include non-transitory computer storage media and communication media, including any medium that facilitates the transfer of computer programs from one place to another.Non-transitory storage media can be any available medium that can be accessed by a general or special computer.As an example and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, CD (CD) ROM or other optical disk storage devices, disk storage devices or other magnetic storage devices, or can be used to carry or store instructions or data structures in the form of desired program code units and can be accessed by a general or special computer, or any other non-transitory medium that a general or special computer can access.Moreover, any connection can be correctly referred to as a computer-readable medium.For example, if software is sent from a website, a server or other remote sources using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology (for example, infrared, radio and microwave), coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology (for example, infrared, radio and microwave) are all included in the definition of computer-readable media. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk usually reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0258] As used herein, including in the claims, "or" as used in a list of items (e.g., a list of items beginning with a phrase such as "at least one" or "one or more") indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Moreover, as used herein, the phrase "based on" should not be interpreted as a reference to a combination of closed conditions. For example, an example step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0259] The terms "determine" or "determining" encompass a wide variety of actions, and thus, "determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., via looking up in a table, database, or other data structure), determining, etc. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Also, "determining" may include solving, selecting, choosing, establishing, and other similar actions.

[0260] In the accompanying drawings, similar components or features may have the same reference number. In addition, various components of the same type may be distinguished by following the reference number with a dash and a second label that distinguishes the similar components. If only the first reference number is used in the specification, the description applies to any one similar component having the same first reference number, regardless of the second or other subsequent reference numbers.

[0261] The description set forth herein in conjunction with the accompanying drawings describes example configurations and does not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "superior to other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some cases, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0262] The description herein is provided to enable one of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but conforms to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a ground base station, comprising: processor; a memory coupled to the processor; as well as Instructions are stored in the memory and can be executed by the processor to cause the device to perform the following operations: sending an indication of a precompensation timing value for transmission of a random access message by an airborne user equipment (UE), the random access message being part of a random access procedure between the ground base station and the airborne UE, wherein the precompensation timing value is based at least in part on a location of the airborne UE; and monitoring a set of random access resources for the random access message based at least in part on the indication, the set of random access resources being associated with the precompensation timing value and the airborne UE, The instructions for sending the indication about the pre-compensation timing value are executable by the processor to cause the apparatus to perform the following operations: Broadcast signaling is sent, the broadcast signaling indicating a plurality of volumetric regions and corresponding region identifiers, wherein each volumetric region of the plurality of volumetric regions is associated with a corresponding pre-compensation timing value for transmission of the random access message by the over-the-air UE.

2. The device according to claim 1, wherein: The instructions for sending the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: The indication of the pre-compensation timing value for transmission of the random access message by the airborne UE is sent, the random access message being part of the random access procedure between the ground base station and the airborne UE when the airborne UE is in a connected state.

3. The device according to claim 1, wherein: The instructions for sending the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: The indication of the pre-compensation timing value is sent to the air UE via radio resource control signaling, a medium access control control element, or downlink control information, wherein the pre-compensation timing value is specific to the air UE.

4. The device according to claim 1, wherein: The instructions for sending the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: An index corresponding to the pre-compensation timing value used for transmitting the random access message by the over-the-air UE is transmitted.

5. The device according to claim 1, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: An indication is sent to the air UE via a dedicated radio resource control message to activate a zone identifier for the air UE.

6. The device according to claim 1, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A bitmap is sent to the air UE via a medium access control element or downlink control information to activate a zone identifier for the air UE.

7. The device according to claim 1, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A list including the plurality of volumetric regions and the corresponding pre-compensation timing values ​​is maintained based at least in part on one or more measurements associated with one or more airborne UEs.

8. The device according to claim 1, wherein: Each pre-compensation timing value corresponds to a minimum value of pre-compensation for a corresponding volumetric region used for random access preamble transmission.

9. The device according to claim 1, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A capability message is received from the airborne UE, the capability message indicating a capability of the airborne UE to measure the position of the airborne UE, apply a pre-compensation timing value, or both.

10. The device according to claim 1, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: After monitoring the set of random access resources for the random access message, a second message of the random access procedure is sent, the second message indicating a timing pre-compensation of the random access message.

11. The device according to claim 1, wherein: The instructions for sending the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: Signaling indicating the location of the ground base station is sent via system information or dedicated radio resource control signaling.

12. The device according to claim 1, wherein: The instructions for sending the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: Sending a signaling to configure a pre-compensation timing value offset to the air UE.

13. The device according to claim 1, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A report is received based at least in part on the completion of the random access procedure, the report indicating the precompensation timing value determined or used by the over-the-air UE.

14. An apparatus for wireless communication at an airborne user equipment (UE), comprising: processor; a memory coupled to the processor; as well as Instructions stored in the memory and executable by the processor to cause the device to perform the following operations: receiving an indication of a pre-compensation timing value for transmission by the airborne UE of a random access message as part of a random access procedure between a ground base station and the airborne UE, wherein the pre-compensation timing value is based at least in part on a location of the airborne UE; and sending the random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the over-the-air UE based at least in part on the received indication, wherein the instructions for receiving the indication regarding the precompensation timing value are executable by the processor to cause the apparatus to: Broadcast signaling is received, the broadcast signaling indicating a plurality of volumetric regions and corresponding region identifiers, wherein each volumetric region of the plurality of volumetric regions is associated with a respective pre-compensation timing value for transmission of the random access message by the over-the-air UE.

15. The device according to claim 14, wherein: The instructions for receiving the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: The indication of the pre-compensation timing value for transmission of the random access message by the airborne UE is received, the random access message being part of the random access procedure between the ground base station and the airborne UE when the airborne UE is in a connected state.

16. The device according to claim 14, wherein: The instructions for receiving the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: receiving signaling indicating the location of the ground base station via system information or dedicated radio resource control signaling; and The precompensation timing value is determined based at least in part on the location of the ground base station.

17. The device according to claim 14, wherein: The instructions for receiving the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: receiving a signaling for configuring a pre-compensation timing value offset to the airborne UE; and The precompensation timing value is determined based at least in part on the precompensation timing value offset.

18. The device according to claim 14, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: The precompensation timing value is determined based at least in part on the location of the ground base station and the location of the airborne UE.

19. The device according to claim 14, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A report indicating the precompensation timing value determined by the over-the-air UE is sent based at least in part on completion of the random access procedure.

20. The device according to claim 14, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: transmitting the random access message using the precompensated timing value via a second random access resource in the set of random access resources based at least in part on the precompensated timing value available at the over-the-air UE; and Based at least in part on the pre-compensated timing value being unavailable at the over-the-air UE, sending the random access message via a third random access resource in the set of random access resources.

21. The device according to claim 14, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A capability message is sent from the airborne UE, the capability message indicating a capability of the airborne UE to measure the position of the airborne UE, apply a pre-compensation timing value, or both.

22. The device according to claim 14, wherein: The instructions for receiving the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: The indication of the pre-compensation timing value is received from the ground base station via radio resource control signaling, a medium access control control element, or downlink control information, wherein the pre-compensation timing value is specific to the airborne UE.

23. The device according to claim 14, wherein: The instructions for receiving the indication of the pre-compensation timing value are executable by the processor to cause the apparatus to: An index corresponding to the pre-compensation timing value for transmission of the random access message by the over-the-air UE is received.

24. The device according to claim 14, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: An indication is received from the ground base station via a dedicated radio resource control message to activate a zone identifier for the airborne UE.

25. The device according to claim 14, wherein: The instructions are also executable by the processor to cause the device to perform the following operations: A bitmap is received from the ground base station via a medium access control element or downlink control information to activate a zone identifier for the airborne UE.

26. The device according to claim 14, wherein: Each pre-compensation timing value corresponds to a minimum value of pre-compensation for a corresponding volumetric region used for random access preamble transmission.

27. A method for wireless communication at a ground base station, comprising: sending an indication of a precompensation timing value for transmission of a random access message by an airborne user equipment (UE), the random access message being part of a random access procedure between the ground base station and the airborne UE, wherein the precompensation timing value is based at least in part on a location of the airborne UE; and monitoring a set of random access resources for the random access message based at least in part on the indication, the set of random access resources being associated with the precompensation timing value and the over-the-air UE, The sending of the indication about the pre-compensation timing value comprises: Broadcast signaling is sent, the broadcast signaling indicating a plurality of volumetric regions and corresponding region identifiers, wherein each volumetric region of the plurality of volumetric regions is associated with a corresponding pre-compensation timing value for transmission of the random access message by the over-the-air UE.

28. A method for wireless communication at an airborne user equipment (UE), comprising: receiving an indication of a precompensation timing value for transmission of a random access message by the airborne UE, the random access message being part of a random access procedure between a ground base station and the airborne UE, wherein the precompensation timing value is based at least in part on a location of the airborne UE; and sending the random access message using a first random access resource in a set of random access resources associated with the precompensation timing value and the airborne UE based at least in part on the received indication, Wherein, receiving the indication about the pre-compensation timing value comprises: Broadcast signaling is received, the broadcast signaling indicating a plurality of volumetric regions and corresponding region identifiers, wherein each volumetric region of the plurality of volumetric regions is associated with a respective pre-compensation timing value for transmission of the random access message by the over-the-air UE.

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