WO2024103767A1

WO2024103767A1 - SYSTEMS AND METHODS FOR PRACH ENHANCEMENT IN UAVs

Info

Publication number: WO2024103767A1
Application number: PCT/CN2023/104102
Authority: WO
Inventors: Yachao YIN; Nan Zhang; Wei Cao; Junli Li
Original assignee: Zte Corporation
Priority date: 2023-06-29
Filing date: 2023-06-29
Publication date: 2024-05-23

Abstract

Presented are systems and methods for physical random access channel (PRACH) enhancement in unmanned aerial vehicles (UAVs). A wireless communication device can transmit a message to a wireless communication node for random access channel (RACH) transmission, determined based on RACH configurations of at least one RACH parameter and associated one or more height information.

Description

SYSTEMS AND METHODS FOR PRACH ENHANCEMENT IN UAVs

TECHNICAL FIELD

The disclosure relates generally to wireless communications, including but not limited to systems and methods for physical random access channel (PRACH) enhancement in unmanned aerial vehicles (UAVs) .

BACKGROUND

The standardization organization Third Generation Partnership Project (3GPP) is currently in the process of specifying a new Radio Interface called 5G New Radio (5G NR) as well as a Next Generation Packet Core Network (NG-CN or NGC) . The 5G NR will have three main components: a 5G Access Network (5G-AN) , a 5G Core Network (5GC) , and a User Equipment (UE) . In order to facilitate the enablement of different data services and requirements, the elements of the 5GC, also called Network Functions, have been simplified with some of them being software based, and some being hardware based, so that they could be adapted according to need.

SUMMARY

The example embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, example systems, methods, devices and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and are not limiting, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of this disclosure.

At least one aspect is directed to a system, method, apparatus, or a computer-readable medium of the following. A wireless communication device (e.g., UE, UAV, and/or other types of aerial devices) can send/transmit/providea message to a wireless communication node (e.g., BS, gNB, and/or network node) for random access channel (RACH) transmission, determined based on RACH configurations of at least one RACH parameter and associated one or more height information (e.g., thresholds, ranges, etc., including one or more values, which can be absolute and/or relative values, etc. ) .

The wireless communication device can receive/obtain/acquire the RACH configurations and the associated one or more height information from the wireless communication node. In some implementations, the message for the RACH transmission can include/comprise at least one of: a preamble, a Msg-Afor two-step random access procedure, and/or a Msg-3.

In some implementations, the at least one RACH parameter can comprise/include a parameter or a set of multiple parameters for use in performing random access or avoiding conflict or collision with at least one other wireless communication device. In some implementations, the at least one RACH parameter can comprise an indication of at least one of: the one or more height information, one or a set of preamble formats, one or a set of PRACH configuration indexes, one or a set of physical random access channel (PRACH) occasions or resources , one or a set of cyclic shift values, one or a set of logical root indexes, one or more types of restricted sets, and/or one or a set of cyclic shift indexes.

In some implementations, receiving the RACH configurations can comprise receiving the RACH configurations via at least one of a first higher layer signaling, a second higher layer signaling, and/or a third higher layer signaling to indicate RACH parameters associated with the one or more height information. In some implementations, the at least one RACH parameter can be configured by the first higher layer signaling, and the associated one or more height information is configured by the second higher layer signaling.

In some implementations, the at least one RACH parameter and the associated one or more height information are jointly configured by the third higher layer singaling including at least one of: the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, height information} , the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, RACH parameter, height information} , the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, height information, height information} , and/or the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, RACH parameter, height information, height information, height information} .

In some implementations, the one or more height information may be configured as at least one of: a single value, at least two values, a range applicable to different RACH parameters, a reference height applicable to different RACH parameters, and/or a threshold applicable to different RACH parameters. In some implementations the one or more height information can comprise at least one of: an absolute height, a relative height relative to a surrounding environment, and/or an absolute height threshold and one or more reference heights. In some implementations, the one or more height information can comprise at least one of: one or more height information configured per cell, and/or one or more height information configured per region.

In some implementations, the at least one RACH parameter can comprise: the one or a set of preamble format and the one or a set of ROs or resources; and/or the one or a set of cyclic shift values and the one or a set of logical root indexes. In some implementations, the wireless communication device can receive the RACH configurations via at least one of: a medium access control (MAC) signaling, a radio resource control (RRC) signaling, a system information block (SIB) signaling, and/or other higher layer signalings from the wireless communication node.

In some implementations, the wireless communication device can receive the RACH configurations from the wireless communication node, after the wireless communication device rises to at least a specific height or the height information. In some implementations, the wireless communication device can receive the RACH configurations from the wireless communication node, each of the RACH configurations comprising at least one RACH parameter that is configured according to a corresponding height information. The wireless communication device can determine a current height of the wireless communication device. The wireless communication device can identify one of the RACH configurations, with a corresponding height information that is higher or lower than the current height.

In some implementations, the one or a set of cyclic shift values can comprise a cyclic shift value that is a smallest of a plurality of cyclic shift values, or comprise a cyclic shift value that is smaller than at least one other cyclic shift value. In some implementations, the one or a set of root index values can comprise a logical root index value that is smallest from a plurality of logical root index values, or comprise a logical root index value that is largest from the plurality of logical root index values. In some implementations, at least one of: the wireless communication device can generate at least one preamble sequence according to at least one of the one or a set of preamble formats, the one or a set of PRACH configuration indexes, the one or a set of logical root index values, the one or a set of cyclic shift values or the type of restricted sets; and/or the wireless communication device can transmit a preamble on a specific RO based on the at least one RACH configuration and whether the wireless communication device is at a height that meets/satisfies the one or more height information, wherein the at least one RACH configuration comprises at least one of the one or a set of PRACH configuration indexes, the one or a set of ROs, or the one or a set of PRACH resources at a height information .

At least one aspect is directed to a system, method, apparatus, or a computer-readable medium of the following. A wireless communication node can receive/obtain/acquire a message from a wireless communication device for random access channel (RACH) transmission, determined based on RACH configurations of at least one RACH parameter and associated one or more height information.

The systems and methods presented herein include a novel approach for PRACH enhancement in UAVs. Specifically, the systems and methods presented herein discuss a novel solution for enhancing PRACH based on or according to a height or altitude of the UE (s) (e.g., including or corresponding to UAV (s) ) . The systems and methods can enhance PRACH for the UE based on the height information (e.g., height threshold or range) with at least one RACH resource and/or parameters for UAV at relatively a high altitude (e.g., at or above at least one predetermined altitude/height information) to avoid, minimize, or prevent conflicts and/or collisions in network communications with other UEs and access target remote BS in consideration of cell load and/or interference.

BRIEF DESCRIPTION OF THE DRAWINGS

Various example embodiments of the present solution are described in detail below with reference to the following figures or drawings. The drawings are provided for purposes of illustration only and merely depict example embodiments of the present solution to facilitate the reader’s understanding of the present solution. Therefore, the drawings should not be considered limiting of the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, these drawings are not necessarily drawn to scale.

FIG. 1 illustrates an example cellular communication network in which techniques disclosed herein may be implemented, in accordance with an embodiment of the present disclosure;

FIG. 2 illustrates a block diagram of an example base station and a user equipment device, in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates an example of a process diagram for implementing PRACH enhancement in UEs, in accordance with some embodiments of the present disclosure;

FIG. 4 illustrates a flow diagram of an example method for PRACH enhancement based on a height threshold, in accordance with some embodiments of the present disclosure;

FIG. 5 illustrates an example scenario of PRACH enhancement for height-based UEs, in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates an example of PRACH resource (RO) allocation for preamble transmission, in accordance with some embodiments of the present disclosure; and

FIG. 7 illustrates a flow diagram of an example method for PRACH enhancement in UAVs, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

1. Mobile Communication Technology and Environment

FIG. 1 illustrates an example wireless communication network, and/or system, 100 in which techniques disclosed herein may be implemented, in accordance with an embodiment of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of things (NB-IoT) network, and is herein referred to as “network 100. ” Such an example network 100 includes a base station 102 (hereinafter “BS 102” ; also referred to as wireless communication node) and a user equipment device 104 (hereinafter “UE 104” ; also referred to as wireless communication device) that can communicate with each other via a communication link 110 (e.g., a wireless communication channel) , and a cluster of cells 126, 130, 132, 134, 136, 138 and 140 overlaying a geographical area 101. In FIG. 1, the BS 102 and UE 104 are contained within a respective geographic boundary of cell 126. Each of the other cells 130, 132, 134, 136, 138 and 140 may include at least one base station operating at its allocated bandwidth to provide adequate radio coverage to its intended users.

For example, the BS 102 may operate at an allocated channel transmission bandwidth to provide adequate coverage to the UE 104. The BS 102 and the UE 104 may communicate via a downlink radio frame 118, and an uplink radio frame 124 respectively. Each radio frame 118/124 may be further divided into sub-frames 120/127 which may include data symbols 122/128. In the present disclosure, the BS 102 and UE 104 are described herein as non-limiting examples of “communication nodes, ” generally, which can practice the methods disclosed herein. Such communication nodes may be capable of wireless and/or wired communications, in accordance with various embodiments of the present solution.

FIG. 2 illustrates a block diagram of an example wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM/OFDMA signals) in accordance with some embodiments of the present solution. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one illustrative embodiment, system 200 can be used to communicate (e.g., transmit and receive) data symbols in a wireless communication environment such as the wireless communication environment 100 of FIG. 1, as described above.

System 200 generally includes a base station 202 (hereinafter “BS 202” ) and a user equipment device 204 (hereinafter “UE 204” ) . The BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each module being coupled and interconnected with one another as necessary via a data communication bus 220. The UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each module being coupled and interconnected with one another as necessary via a data communication bus 240. The BS 202 communicates with the UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for transmission of data as described herein.

As would be understood by persons of ordinary skill in the art, system 200 may further include any number of modules other than the modules shown in FIG. 2. Those skilled in the art will understand that the various illustrative blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein may be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. To clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are described generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software can depend upon the particular application and design constraints imposed on the overall system. Those familiar with the concepts described herein may implement such functionality in a suitable manner for each particular application, but such implementation decisions should not be interpreted as limiting the scope of the present disclosure.

In accordance with some embodiments, the UE transceiver 230 may be referred to herein as an “uplink” transceiver 230 that includes a radio frequency (RF) transmitter and a RF receiver each comprising circuitry that is coupled to the antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in time duplex fashion. Similarly, in accordance with some embodiments, the BS transceiver 210 may be referred to herein as a “downlink” transceiver 210 that includes a RF transmitter and a RF receiver each comprising circuity that is coupled to the antenna 212. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in time duplex fashion. The operations of the two transceiver modules 210 and 230 may be coordinated in time such that the uplink receiver circuitry is coupled to the uplink antenna 232 for reception of transmissions over the wireless transmission link 250 at the same time that the downlink transmitter is coupled to the downlink antenna 212. Conversely, the operations of the two transceivers 210 and 230 may be coordinated in time such that the downlink receiver is coupled to the downlink antenna 212 for reception of transmissions over the wireless transmission link 250 at the same time that the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is close time synchronization with a minimal guard time between changes in duplex direction.

The UE transceiver 230 and the base station transceiver 210 are configured to communicate via the wireless data communication link 250, and cooperate with a suitably configured RF antenna arrangement 212/232 that can support a particular wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as the Long Term Evolution (LTE) and emerging 5G standards, and the like. It is understood, however, that the present disclosure is not necessarily limited in application to a particular standard and associated protocols. Rather, the UE transceiver 230 and the base station transceiver 210 may be configured to support alternate, or additional, wireless data communication protocols, including future standards or variations thereof.

In accordance with various embodiments, the BS 202 may be an evolved node B (eNB) , a serving eNB, a target eNB, a femto station, or a pico station, for example. In some embodiments, the UE 204 may be embodied in various types of user devices such as a mobile phone, a smart phone, a personal digital assistant (PDA) , tablet, laptop computer, wearable computing device, etc. The processor modules 214 and 236 may be implemented, or realized, with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, a processor may be realized as a microprocessor, a controller, a microcontroller, a state machine, or the like. A processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.

Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in firmware, in a software module executed by processor modules 214 and 236, respectively, or in any practical combination thereof. The memory modules 216 and 234 may be realized as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to the processor modules 210 and 230, respectively, such that the processors modules 210 and 230 can read information from, and write information to, memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by the processor modules 210 and 230, respectively.

The network communication module 218 generally represents the hardware, software, firmware, processing logic, and/or other components of the base station 202 that enable bi-directional communication between base station transceiver 210 and other network components and communication nodes configured to communication with the base station 202. For example, network communication module 218 may be configured to support internet or WiMAX traffic. In a typical deployment, without limitation, network communication module 218 provides an 802.3 Ethernet interface such that base station transceiver 210 can communicate with a conventional Ethernet based computer network. In this manner, the network communication module 218 may include a physical interface for connection to the computer network (e.g., Mobile Switching Center (MSC) ) . The terms “configured for, ” “configured to” and conjugations thereof, as used herein with respect to a specified operation or function, refer to a device, component, circuit, structure, machine, signal, etc., that is physically constructed, programmed, formatted and/or arranged to perform the specified operation or function.

The Open Systems Interconnection (OSI) Model (referred to herein as, “open system interconnection model” ) is a conceptual and logical layout that defines network communication used by systems (e.g., wireless communication device, wireless communication node) open to interconnection and communication with other systems. The model is broken into seven subcomponents, or layers, each of which represents a conceptual collection of services provided to the layers above and below it. The OSI Model also defines a logical network and effectively describes computer packet transfer by using different layer protocols. The OSI Model may also be referred to as the seven-layer OSI Model or the seven-layer model. In some embodiments, a first layer may be a physical layer. In some embodiments, a second layer may be a Medium Access Control (MAC) layer. In some embodiments, a third layer may be a Radio Link Control (RLC) layer. In some embodiments, a fourth layer may be a Packet Data Convergence Protocol (PDCP) layer. In some embodiments, a fifth layer may be a Radio Resource Control (RRC) layer. In some embodiments, a sixth layer may be a Non Access Stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer being the other layer.

Various example embodiments of the present solution are described below with reference to the accompanying figures to enable a person of ordinary skill in the art to make and use the present solution. As would be apparent to those of ordinary skill in the art, after reading the present disclosure, various changes or modifications to the examples described herein can be made without departing from the scope of the present solution. Thus, the present solution is not limited to the example embodiments and applications described and illustrated herein. Additionally, the specific order or hierarchy of steps in the methods disclosed herein are merely example approaches. Based upon design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be re-arranged while remaining within the scope of the present solution. Thus, those of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or acts in a sample order, and the present solution is not limited to the specific order or hierarchy presented unless expressly stated otherwise.

2. Systems and Methods for PRACH Enhancement in UAVs

In a certain terrestrial network, one or more UEs 104 (e.g., wireless communication device or terminal) may be located/positioned at an altitude/height lower/less than the BS 102 (e.g., gNB or wireless communication node) . In some scenarios, the UE 104 may be considered as or corresponding to a UAV (e.g., drone or other types of aerial vehicles or devices) , which may propagate or communicate with a relatively high probability/likelihood (e.g., of reception and/or reception of signals with one or more BSs 102) in the line of sight (LOS) channel (e.g., transmission path without a relatively significant obstruction) at relatively high altitude with relatively good coverage, such that an increased number of cells may be identified, foreseen, or accessed. Because of the relatively larger/wider/bigger coverage area at the relatively higher altitude (e.g., in the air) compared to the relatively lower altitude (e.g., on the ground) , comparatively fewer or lower number of BSs 102 can be deployed for UEs 104 (e.g., UAVs) at the relatively higher altitude. In some cases, when the altitude of the UEs 104 rises/increases from low to high altitudes, PRACH enhancement can be considered (e.g., configured) for matching or corresponding to the coverage range in the air (or at the certain altitude) and/or accessing the target BS 102. In some other cases, when the UEs 104 are connected to one or more remote BSs 102 at relatively high altitudes, it may be desired to reduce potential conflicts and/or collisions between the UEs 104, such as the UAVs, and other terrestrial UEs 104 (e.g., UEs 104 at relatively lower altitudes) during random access. Hence, the systems and methods of the technical solution discussed herein can provide PRACH enhancement for UEs 104 at relatively high altitudes to avoid, minimize, or prevent conflicts and/or collisions with other UEs 104 and/or access target remote BS 102 (e.g., at least one BS 102 within a cell capable of serving the UE 104 at its current altitude) with consideration of cell load (e.g., load balancing network resources for various cells) and/or interference.

In certain systems, random access preambles (e.g., a preamble sequence) can be generated by or based on Zadoff-Chu (ZC) sequences with zero correlation, for example. In some cases, there may be 64 (or other numbers of) available preamble sequences in each respective cell. Adjacent BSs 102 can be assigned different sets of random access sequences. These sequences (e.g., preamble sequences) may be obtained/acquired by a cyclic shift of a root ZC sequence, which can be arranged/organized in ascending order (or descending order) according to the available cyclic shift values of the root ZC sequence. The logical index in the root ZC sequence can be broadcast by/via system information. If a certain root ZC sequence cannot generate the predetermined number of preamble sequences (e.g., the entire 64 preamble sequences) via/through the cyclic shift, the remaining preamble sequences can be generated by the subsequent root ZC sequence corresponding to the logical index values via the cyclic shift. The specific ZC sequence generated by the cyclic shift corresponding to a certain logical index can include or correspond to the following:
X_U, V (n) =x_u (n+C_v ) modL_RA

The ZC sequence can be defined, described, or represented as the following:

The L_RA can correspond to the logical root index value. The C_v can correspond to the cyclic shift.

In certain systems, different types of PRACH preamble can be defined/described to provide the corresponding coverage for various cell radii/areas, for example, according to, but not limited to, the following tables (e.g., example Table 1 and example Table 2) .

Example Table 1: PRACH preamble formats for L_RA=839 and Δf_RA∈ {1.25, 5} kHz

Example Table 2: Preamble formats for L_ (RA) ∈ {139, 571, 1151} and Δf_RA=15·2^μ kHz where μ∈ {0, 1, 2, 3, 5, 6}

In certain systems, random access occasion (RO) (e.g., sometimes referred to as or include resource occasion) can be specified//indicated/configured/defined by the configuration of the network or the BS 102. The synchronization signal block (SSB) can be associated with different beams/signals. The mapping (or association) between the SSB and the RO can be defined/configured by, via, or using the radio resource control (RRC) parameters, e.g., msg1-FDM and/or ssb-perRACH-OccasionAndCB-PreamblesPerSSB, etc.

Referring to FIG. 3, depicted is an example of a process diagram 300 for implementing PRACH enhancement in UEs 104 (e.g., UAVs) . In various implementations, to enhance PRACH for UEs 104 at a relatively high altitude (e.g., at or above at least one predetermined threshold, discussed herein) , the BS 102 can configure/set/implement one or more random access parameters and/or information for the UE 104 in high altitude to avoid conflicts and/or collisions. The BS 102 (or the network) can send/provide/communicate the parameters or configuration information to the UE 104 via signaling and/or assistance information, such as a medium access control (MAC) signaling, a radio resource control (RRC) signaling, a system information block (SIB) signaling, or other higher layer signalings. At least one of the following example configurations can be implemented:

1. Example configuration 1: when the height/altitude of the UE 104 is at or above/or is greater than a predetermined height threshold, the BS 102 can configure or indicate the height threshold (e.g., the same or different height threshold) and a preamble format for the UE 104. In this case, at least the preamble format can be a part of the parameter used to perform random access (or for avoiding conflict or collision with at least one other UEs 104 below the height threshold) .

2. Example configuration 2: when the height of the UE 104 is at or above the predetermined height threshold, the BS 102 can configure or indicate the height threshold and at least one PRACH resource (or PRACH occasion) (RO) for the UE 104. In this case, at least the RO can be a part of the parameter used to perform random access (or for avoiding conflict or collision with at least one other UEs 104 below the height threshold) .

3. Example configuration 3: when the height of the UE 104 is at or above the predetermined height threshold, the BS 102 can configure or indicate the height threshold and at least one preamble format with the corresponding RO for the UE 104. In this case, at least the preamble format and the corresponding RO can be a part of the parameter used to perform random access (or for avoiding conflict or collision with at least one other UEs 104 below the height threshold) .

4. Example configuration 4: when the height of the UE 104 is at or above the predetermined height threshold, the BS 102 can configure or indicate the height threshold and a cyclic shift value of N_cs (or a number of cyclic shift) for a preamble sequence generation. In this case, at least the cyclic shift value/number can be a part of the parameter used to perform random access (or for avoiding conflict or collision with at least one other UEs 104 below the height threshold) .

5. Example configuration 5: when the height of the UE 104 is at or above the predetermined height threshold, the BS 102 can configure or indicate the height threshold and a logical root index value for the preamble sequence generation. In this case, at least the logical root index value can be a part of the parameter used to perform random access (or for avoiding conflict or collision with at least one other UEs 104 below the height threshold) .

6. Example configuration 6: when the height of the UE 104 is at or above the predetermined height threshold, the BS 102 can configure or indicate the height threshold and a logical root index value with the corresponding cyclic shift value for the preamble sequence generation. In this case, at least the logical root index value and the corresponding cyclic shift value can be a part of the parameter used to perform random access (or for avoiding conflict or collision with at least one other UEs 104 below the height threshold) .

Example Configuration 1: BS Configures at least one Preamble Format

Referring to FIG. 4, depicted is a flow diagram of an example method 400 for PRACH enhancement based on a height threshold. FIG. 5 illustrates an example scenario 500 of PRACH enhancement for height-based UEs 104, such as described in conjunction with but not limited to the example method 400 of FIG. 4. The example method 400 can be initiated in response to the height/altitude of the UE 104 reaching or exceeding the height threshold, such as shown in FIG. 5. The UE 104 can connect to one or more (e.g., remote) BSs 102, such as the BS 102 associated with at least one of cells A-E depending on the location of the UE 104. The preamble format for the UE 104 can be configured, for example, as follows:

At operation 402, the BS 102 (or network) can broadcast, send, or provide one or more height/altitude thresholds and the random access preamble format (or RACH resource configurations) corresponding to or according to the height of the UE 104 (e.g., UAV) being at or above the one or more height thresholds. The BS 102 can broadcast the information to the UE 104 via the SIB signaling, among other types of signalings.

At operation 404, the UE 104 can obtain its height based on or according to the global navigation satellite system (GNSS) or other types of positioning system configured to measure at least the altitude, height, or position of the UE 104. In some cases, the height of the UE 104 may vary based on the capability of the GNSS. At operation 406, the UE 104 can determine whether the height of the UE 104 is (at or) higher than the height/altitude threshold configured by the BS 102 or the network. Referring to FIG. 5, for example at time t₂, the UE 104 can obtain or receive an indication, from the positioning system, that a flight altitude of the UE 104 is at or higher than the height threshold. In this case, the UE 104 can start/initiate accessing the target remote BS 102 based on the received synchronization signal block (SSB) .

The UE 104 can receive/obtain the downlink (DL) SSB for downlink synchronization and/or system and broadcast information, such as the RACH resource configuration via the SIB signaling, or other signalings, from the BS 102. At operation 408, the UE 104 can apply the RACH resource configuration at the corresponding height threshold for RACH, e.g., to be random-access connected (e.g., connected via random access procedure) based on the provided preamble format configured by the BS 102, where the preamble format can be configured by the BS 102 according to the respective altitude threshold. For example, considering the Doppler frequency offset generated by the (e.g., flight, travel, or movement) speed of the UE 104, the type of predetermined/predefined/restricted sets supported for PRACH preamble formats of, but not limited to, L_RA=839, such as preamble formats 0 to 3, can be used by the UE 104, such as in the example Table 1. In this case, the preamble format in the example Table 1, e.g., PRACH preamble format 0, can be applied for the UE 104 when the flight height of the UE 104 is at or above the predetermined height threshold. Other PRACH preamble formats can be applied for the UE 104 based on other parameters, such as according to the example Table 1.

In some implementations, while the height of the UE 104 is less than the height threshold, the UE 104 can apply legacy RACH resource configurations for RACH, at operation 410. In this case, the UE 104, such as a UAV, can operate or be configured by the BS 102 similarly to other terrestrial UE 104, for example.

In some implementations, the BS 102 or the network can configure the dedicated RRC signaling (e.g., SIB signaling or other types of signalings) to the UE 104 with mulitple height thresholds. For example, one or more height thresholds can include or correspond to at least one of, but not limited to, 30 meters, 50 meters, 100 meters, 300 meters, 500 meters, etc. One or more configured preamble formats can include at least preamble format 0, preamble format 1, preamble format 2, and/or preamble format 3. The BS 102 can broadcast the multiple height thresholds and/or preamble formats individually or concurrently (e.g., together) as part of the random access configurations to the UE 104.

Example Configuration 2: BS Configures a Specific RO

In various configurations, when the height of the UE 104 is at or above the height threshold (e.g., based on GNSS or other positioning system measurements) , the UE 104 can access at least one remote BS 102 based on certain configurations. For example, the UE 104 can access the remote BS 102 based on or according to at least one (e.g., specific) RO configured by the BS 102, such as follows:

1. The BS 102 can broadcast the height threshold and the RO corresponding to or associated with the height of the UE 104 exceeding at least one height threshold (e.g., the specific RO can be associated with the height threshold) via/through the system information block (SIB) signaling or other types of signalings.

2. Based on the GNSS capability of the UE 104, if the height of the UE 104 is at or above the height threshold configured by the BS 102, the UE 104 can start/initiate accessing the target remote BS 102 based on the received SSB from the BS 102, such as via the SIB signaling.

3. The UE 104 can receive/obtain the downlink SSB for downlink synchronization and/or the system and broadcast information from the BS 102.

4. The UE 104 can be random-access connected (e.g., connected via random access procedure) based on the RO configured by the BS 102. The specific RO can be based on the height threshold configured by the BS 102. For example, FIG. 6 depicts an example 600 of RO allocation for preamble transmission. As shown, the specific RO can be allocated or mapped to preamble transmission (e.g., respective SSB) for the UE 104. Although FIG. 6 provides a certain number of SSBs (e.g., 64 preamble sequences) and associated ROs, the BS 102 may configure other numbers of preamble sequences.

In some implementations, the BS 102 can configure the dedicated RRC signaling (e.g., SIB or other types of signalings) to the UE 104 with different height thresholds. For example, one or more height thresholds can include but are not limited to 30 meters, 50 meters, 100 meters, 300 meters, 500 meters, etc. One or more (e.g., specialized, unique, or configured) time resources of RO can include or correspond to, for instance, PRACH configuration index 0, PRACH configuration index 1, PRACH configuration index 2, PRACH configuration index 3, etc. The BS 102 can broadcast multiple height thresholds and RO individually or concurrently/together as part of random access resources for the UE 104.

Example Configuration 3: BS Configures Preamble Format and RO

In various configurations, the BS 102 can configure at least one specific preamble format at a specific RO resource (e.g., time and/or frequency resources) for preamble transmission. Based on the preamble transmission in this case (e.g., the preamble format and the RO resource) , the different states of the UE 104 will be differentiated/distinguished and the UE 104 can be connected to the target remote BS 102. The preamble format configurations and the RO resource can be implemented or utilized as follows:

1. The BS 102 can broadcast the height threshold, the random access preamble format, and the RO corresponding to the height of the UE 104 (e.g., associated with the height threshold) at or above the height threshold via the SIB signaling or other types of signalings.

2. The UE 104 can determine or obtain a measurement of its height/altitude based on the positioning system (e.g., GNSS) capability of the UE 104. If the flight height of the UE 104 is at or above the height threshold configured by the BS 102, the UE 104 can start accessing the target remote BS 102 based on the received SSB from the BS 102.

3. The UE 104 receives the downlink SSB from the BS 102 for downlink synchronization and obtains system and broadcast information via at least one suitable signaling.

4. The UE 104 can transmit/send/provide a certain preamble format at the specified RO (e.g., time or frequency) as configured by the BS 102. The specific RO and/or preamble format based on the height threshold can be configured by the BS 102. For example, considering the Doppler frequency offset generated by the movement or flight speed of the UE 104 and avoiding cell interference, the UE 104 can transmit at least preamble format 0 at a special RO, among other preamble formats, such as based on the speed and/or height of the UE 104.

In some implementations, the BS 102 can configure the dedicated RRC signaling (e.g., SIB, etc. ) to the UE 104 with multiple height thresholds. For example, one or more height thresholds can include at least one of 30 meters, 50 meters, 100 meters, 300 meprters, 500 meters, etc. One or more specialized preamble formats can include or be preamble format 0, preamble format 1, preamble format 2, and/or preamble format 3, etc. One or multiple time resources of RO can include PRACH configuration index 0, PRACH configuration index 28, PRACH configuration index 34, and PRACH configuration index 40 for preamble format 0, preamble format 1, preamble format 2, and preamble format 3, respectively, among other configurations. The BS 102 can broadcast multiple height thresholds, specific RO, and preamble format individually or concurrently/together as part of the random access configurations for the UE 104.

Example Configuration 4: Specific cyclic shift value is configured by BS

In some configurations, the generation of preamble sequences can be determined by or according to cyclic shift values. In this case, the BS 102 can configure/set specific cyclic shift values for the UE 104 to access the target BS 102 during random access, such as according to but not limited to the following example operations:

1. The BS 102 can broadcast the height threshold and one or more cyclic shift values corresponding to the height of the UE 104 at or above at least one height threshold via the SIB signaling.

2. Based on the GNSS capability of the UE 104, if the UE 104 flight height is at or above the height threshold configured by the BS 102, the UE 104 can start accessing the target remote BS 102 based on the received SSB from the BS 102.

3. The UE 104 can receive/obtain/acquire the downlink SSB for downlink synchronization and obtain system and broadcast information from the BS 102.

4. The UE 104 can generate a preamble sequence based on at least one of the cyclic shift values configured by the BS 102. The cyclic shift value used for generating the preamble sequence can be based on the height threshold configured by the BS 102. To avoid/prevent cell interference between the UE 104 (e.g., UAV) at or above the height threshold and other UEs 104, such as terrestrial UEs 104 below the height threshold, a relatively smaller cyclic shift value (s) can be configured for the UE 104 at the relatively higher altitude to reduce the number of logical root index values for different cells. The relatively smaller cyclic shift values can result in a relatively lower likelihood/probability of conflict between the UE 104 at or above the height threshold and other terrestrial UEs 104 below the height threshold. By considering the Doppler frequency offset generated by or based on the flight speed of the UE 104, the cyclic shift values (e.g., N_cs) corresponding to the type of restricted sets supported for PRACH preamble formats can be considered for avoiding the cell interference. For example, the minimum (or smallest) cyclic shift values, e.g., such as but not limited to 15 and 36 of example Table 2 and example Table 3, respectively, can be configured to generate a preamble sequence for the UE 104. In another example, a cyclic shift value that is relatively smaller compared to at least one other cyclic shift value, such as but not limited to 2, 8, and/or 17 of example Table 5, can be configured to generate preamble sequence for PRACH preamble formats of L_RA=139, 571, and 1151 of the example Table 5, respectively. In such cases, the conflicts and collisions between the UE 104 at or above the height threshold and other UEs 104 below the height threshold can be minimized or avoided.

Example Table 3: Ncs for preamble formats with Δf_RA=5 kHz

In some implementations, the BS 102 can configure the dedicated RRC signaling (e.g., SIB) for the UE 104 with different or multiple height thresholds. For example, one or more height thresholds can include, but not limited to, 30 meters, 50 meters, 100 meters, 300 meters, 500 meters, etc. One or more configured cyclic shift values can include at least 15 and/or 18, among others. One or more indexes of zeroCorrelationZoneConfig can include 0 and/or 1, for example. The BS 102 can broadcast multiple height thresholds and cyclic shift values together or individually as a random access configuration for the UE 104.

Example Table 4: N_cs for preamble formats with Δf_RA = 5 kHz

Example Table 5: N_cs for preamble formats with L_RA∈ {139, 571, 1151}

Example Configuration 5: BS Configures at least one Logical Root Index Value

In various configurations, the UE 104 can generate at least one preamble sequence according to, based on, or determined by at least one logical root index value. The BS 102 can configure one or more logical root index values for the UE 104 to access the target BS 102 during the random access, such as according to the following example operations or processes:

1. The BS 102 can broadcast/propagate the height threshold, at least one logical root index value corresponding to or associated with the height of (or the height threshold reached by) the UE 104 at or above the height threshold via the SIB signaling.

2. Based on the GNSS capability of the UE 104, if the flight height of the UE 104 is at or above the height threshold configured by the BS 102, the UE 104 can start accessing the target remote BS 102 based on the received SSB from the BS 102.

3. The UE 104 can receive the downlink SSB for downlink synchronization and obtain system and broadcast information from the BS 102.

4. The UE 104 can generate a preamble sequence based on the at least one (e.g., specific) logical root index value configured by the BS 102. The specific logical root index value can be associatd with or based on the height threshold, which can be configured by the BS 102. For example, the BS 102 can configure the maximum and/or minimum value (s) of the root index for the UE 104, such as a logical root index value that is the smallest from various logical root index values (e.g., value of 1) and/or a logical root index value that is the largest from various logical root index values (e.g., value of 838, etc. ) can be configured for the UE 104 when the flight height of the UE 104 is at or above the height threshold.

In some implementations, the BS 102 can configure/set/establish the dedicated RRC signaling (e.g., SIB or other types of signalings) to the UE 104 with different height thresholds. For example, one or more height thresholds can include but are not limited to 30 meters, 50 meters, 100 meters, 300 meters, 500 meters, etc. One or more configured logical root index values can include 1, 838, etc. One or multiple indexes of logical root values, e.g., prach-RootSequenceIndex can include or correspond to 22 and 23, such as for logical root values that are 1 and 838, respectively, for example. The BS 102 can broadcast multiple height thresholds and logical root index values together or individually as part of the random access configuration to the UE 104.

Example Configuration 6: BS Configures Cyclic Shift and Logical Root Index Value

In some configurations, the BS 102 can configure at least one logical root index value and at least one cyclic shift value for generating the preamble sequence, such as to differentiate/distinguish the states of the UE 104 and for the UE 104 to be connected to the target remote BS 102. The at least one logical root index value and at least one cyclic shift value can be implemented or utilized by the BS 102 and/or the UE 104 as follows:

1. The BS 102 can broadcast the height threshold, at least one logical root index value, and at least one cyclic shift value corresponding to the height of the UE 104 at or above the height threshold via the SIB signaling.

2. Based on the GNSS capability of the UE 104, if the flight height of the UE 104 is at or above the height threshold configured by the BS 102, the UE 104 will start accessing the target remote BS 102 based on the received SSB from the BS 102.

4. The UE 104 can generate a preamble sequence based on the at least one (e.g., specific) cyclic shift value and logical root index value configured by the BS 102, among other parameters. The individual cyclic shift values and/or logical root index values can be based on or associated with one or more height thresholds, such as configured by the BS 102. For example, by considering the Doppler frequency offset caused by the flight speed of the UE 104 and avoiding cell interference, the BS 102 can configure at least one relatively small cyclic shift value and/or at least one minimum logical root index value, such as 15 and 1, respectively, for the type of restricted sets supported for PRACH preamble formats of L_RA=839, among other preamble formats.

In various implementations, the UE 104 can receive one or more other configurations (or parameters) broadcasted from the target BS 102 when the UE 104 is at or above the height threshold. The UE 104 can determine its height and the corresponding parameters to apply for connection with the target BS 102. In some cases, the UE 104 can determine the parameter to apply according to the corresponding height threshold and the current height of the UE 104, such as a height threshold closest to or less than the current height of the UE 104, for example. Based on the corresponding parameter (s) , the UE 104 can apply the parameter discussed herein to connect with the target BS 102.

In some implementations, the BS 102 can configure the dedicated RRC signaling (e.g., SIB signaling or other types of signalings) to the UE 104 with different height thresholds. For example, one or more height thresholds can include 30 meters, 50 meters, 100 meters, 300 meters, 500 meters, etc. In some examples, one or more cyclic shift values and logical root index values can include, but are not limited to, at least 15 and 1, respectively, for PRACH preamble formats of LRA=839. In some other examples, one or more cyclic shift values and logical root index values can include, but are not limited to, at least 2 and 1, respectively, for PRACH preamble formats of LRA=139. The BS 102 can broadcast multiple height thresholds, cyclic shift values, and/or logical root index values concurrently/together or individually, for instance, as part of the random access configuration for the UE 104.

FIG. 7 illustrates a flow diagram of an example method 700 for PRACH enhancement in UEs (e.g., UAVs) . The method 700 may be implemented using any one or more of the components and devices detailed herein in conjunction with FIGs. 1–6. In brief overview, the method 700 may be performed by at least one wireless communication device (e.g., a UE, UAV, or other types of aerial devices) , at least one wireless communication node (e.g., a BS, gNB, or access network equipment) , etc., in some embodiments. Additional, fewer, or different operations may be performed in the method 700 depending on the embodiment. At least one aspect of the operations can be directed to a system, method, apparatus, or a computer-readable medium.

At operation 702, a wireless communication node can send/transmit/communicate/signal/provide the random access channel (RACH) configurations (e.g., assistance information or configuration) that are associated with one or more height information (e.g., height thresholds or ranges) to a wireless communication device. At operation 704, the wireless communication device can receive/obtain/acquire the RACH configurations from the wireless communication node. At operation 706, the wireless communication device can transmit a message to the wireless communication node for RACH transmission, determined based on RACH configurations of at least one RACH parameter and associated one or more height information. At operation 708, the wireless communication node can receive the message from the wireless communication device.

In some implementations, the message for the RACH transmission can include at least one of: a preamble, a Msg-Afor two-step random access procedure, and/or a Msg-3. In some implementations, the at least one RACH parameter from RACH configurations can include at least a parameter or a set of multiple parameters for use in performing random access or avoiding conflict or collision with at least one other wireless communication device. In some cases, the at least one RACH parameter can include an indication of at least one of: one or more height information, one or a set of preamble formats, one or a set of PRACH configuration indexes, one or a set of physical random access channel (PRACH) occasions or resources, one or a set of cyclic shift values, one or a set of logical root indexes, one or more types of restricted sets, and/or one or a set of cyclic shift indexes.

In some implementations, receiving the RACH configurations can comprise, for instance, the wireless communication device receiving the RACH configurations via at least one of a first higher layer signaling, a second higher layer signaling, and/or a third higher layer signaling to indicate RACH parameters associated with the one or more height information, or other types of signalings. In some implementaitons, at least one RACH parameter may be configured by the first higher layer signaling, and the associated one or more height information may be configured by the second higher layer signaling.

In some implementations, the at least one RACH parameter and the associated one or more height information may be jointly configured by the third higher layer singaling including at least one of: the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, height information} , the at least one RACH parameter and the associated one or more height information are configured in pair (or group) {RACH parameter, RACH parameter, height information} , the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, height information, height information} , and/or the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, RACH parameter, height information, height information, height information} .

In some implementations, the one or more height information can be configured as at least one of: a single value, at least two values, a range applicable to different RACH parameters, a reference height applicable to different RACH parameters, and/or a threshold applicable to different RACH parameters. In some implementations, the one or more height information comprise at least one of: an absolute height, a relative height relative to a surrounding environment, and/or an absolute height threshold and one or more reference heights. In some implementations, the one or more height information may comprise at least one of: one or more height information configured per cell, and/or one or more height information configured per region.

In some implementations, the wireless communication device can receive one or more configurations from the wireless communication node. Each configuration can include at least one parameter that is configured according to a corresponding height information. For example, the wireless communication device may be configured with multiple height thresholds or ranges. The wireless communication device can determine, based on at least one measurement from the positioning system, the current height of the wireless communication device. The wireless communication device can identify at least one of the various RACH configurations, with a corresponding height information that is higher or lower than the current height. In this case, each configuration may be associated with a respective height threshold of the various height thresholds configured by the wireless communication node.

In some implementations, the one or a set of cyclic shift values can include a cyclic shift value that is a smallest one of various cyclic shift values, and/or include a cyclic shift value that is relatively smaller than at least one other cyclic shift value. In some implementations, the one or a set of root index values can include a logical root index value that is the smallest (e.g., minimum) from various logical root index values, and/or include a logical root index value that is the largest (e.g., maximum) from the various logical root index values.

In some implementations, at least one of: the wireless communication device can generate at least one preamble sequence according to at least one of the one or a set of preamble formats, the one or a set of PRACH configuration indexes, the one or a set of logical root index values, the one or a set of cyclic shift values, and/or the type of restricted sets; and/or the wireless communication device may transmit/send a preamble on a specific RO based on the at least one RACH configuration and whether the wireless communication device is at a height that meets/satisfies (e.g., at or above) the one or more height information, where the at least one RACH configuration comprises at least one of the one or a set of PRACH configuration indexes, the one or a set of ROs, and/or the one or a set of PRACH resources at a height information.

In various implementations, receiving the RACH configurations can comprise receiving the RACH configurations via at least one of a first higher layer signaling, a second higher layer signaling, and/or a third higher layer signaling to indicate RACH parameters associated with the one or more height information. For example, at least one RACH configuration/parameter can be configured via a first higher layer signaling. The higher layer signaling can comprise at least one of: a medium access control (MAC) signaling, a radio resource control (RRC) signaling, a system information block (SIB) signaling, or other higher layer signalings. For example, one or a set of preamble formats (e.g., x1, x2, x3, etc. ) can be configured via an indication of prach-ConfigurationIndex in higher layer signaling (e.g., a RRC signaling of information element (IE) RACH-ConfigGeneric) . In some examples, one or a set of cyclic shift values (e.g., y1, y2, y3, etc. ) can be configured via an indication of zeroCorrelationZoneConfig and/or an indication of restrictedSetConfig in higher layer signaling (e.g., an RRC signaling of IE RACH-ConfigGeneric) . In some other examples, one or a set of logical root indexes (e.g., z1, z2, z3, etc. ) can be configured via an indication of prach-RootSequenceIndex in higher layer signaling (e.g., an RRC signaling of RACH-ConfigCommon) . In certain examples, one or a set of physical random access channel (PRACH) occasions or resources (e.g., m1, m2, m3, etc. ) can be configured via an indication of SharedRO-MaskIndex in higher layer signaling (e.g., SIB, RRC, MAC, etc. ) . In some examples, one or a set of physical random access channel (PRACH) occasions or resources (e.g., m1, m2, m3, etc. ) can be configured via an indication of msg1-FDM, msgA-RO-FDM, msg1-FrequencyStart or msgA-RO-FrequencyStart in higher layer signaling (e.g., an RRC signaling of RACH-ConfigGeneric and/or RACH-ConfigGenericTwoStepRA) . In some cases, one or more height information (e.g., n1, n2, n3, etc. ) can be configured via an indication of Height-Thresholds in higher layer signaling (e.g., SIB, RRC, MAC, etc. ) .

In some implementations, the at least one RACH parameter can be configured via a second higher layer signaling. The second higher layer signaling can comprise at least one of: a medium access control (MAC) signaling, a radio resource control (RRC) signaling, a system information block (SIB) signaling, or other higher layer signaling. For example, one or more height information (e.g., n1, n2, n3, and/or n1<n2<n3, etc. ) can be configured via an indication of Height-Thresholds in higher layer signaling (e.g., a RRC signaling of IE Height-Config) . In some examples, the configured height information can define a range that corresponds to different parameters for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device (e.g., format x1 can be used when the current height is lower than n1, format x2 can be used when the current height is lower than n2 and higher than n1, format x3 can be used when the current height is lower than n3, etc. ) . In some other examples, the configured height information can define, include, or represent a threshold that corresponds to parameter values for use in performing random access or avoiding conflict except for legacy RACH parameter values (e.g., format x1 may be used when the current height is lower than n1, format x2 may be used when the current height is higher than n1, format x3 may be used when the current height is higher than n2, etc. ) . The same mapping method between height information and the other parameter (e.g., cyclic shift values, logical root indexes, etc. ) can be applied. For other RACH parameters not indicated in the third higher layer signaling, maintain consistency with the legacy RACH parameter (e.g., the first higher layer signaling) .

In some implementations, the at least one RACH parameter can be configured via an third higher layer signaling. The third higher layer signaling can comprise at least one of: a medium access control (MAC) signaling, a radio resource control (RRC) signaling, a system information block (SIB) signaling, or other higher layer signalings. For example, the combination between one or more height information (e.g., n1, n2, n3, etc. ) and one or a set of preamble formats can be configured via an indication in higher layer signaling (e.g., an RRC signaling of IE Height-Config) , for instance, (x1, n1) , (x2, n2) , or (x2, n1) , (x3, n2) , etc. The former combination (x1, n1) can be defined as using format x1 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is lower than height information n1, and/or the later combination (x2, n1) can be defined as using format x2 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is higher than n1. In some examples, the combination between multiple parameters and height information can be configured via an indication in higher layer signaling (e.g., an RRC signaling of IE Height-Config) , for instance, (x1, z1, n1) , (x2, z2, n2) , or (x2, z1, n1) , (x3, z1, n2) , etc. The former combination (x1, z1, n1) can be defined as using format x1 and logical root index z1 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is lower than height threshold n1, and/or the later combination (x2, z1, n1) can be defined as using format x2 and logical root index z1 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is higher than n1. In some examples, the combination between more height information (e.g., n1, n2, n3, etc. ) and at least one preamble format can be configured via an indication in higher layer signaling (e.g., an RRC signaling of IE Height-Config) , for instance, (x1, n1, n2) , (x2, n2, n3) , and/or (x1, x2, n1, n2, n3) , etc. The combination (x1, n1, n2) can be defined as using format x1 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is higher than height threshold n1 and lower than height threshold n2. The combination (x1, n1, n2) can be defined as using format x1 for use in performing random access or avoiding conflict or collision with at least one other wireless communication device when the current height is within the height range of n2 starting from n1 height thresholds. In some other examples, the combination between more height information (e.g., n1, n2, n3, etc. ) and more preamble formats can be configured via an indication in higher layer signaling (e.g., an RRC signaling of IE Height-Config) , for instance, (x1, x2, n1, n2, n3) , etc. The combination (x1, x2, n1, n2, n3) can be defined as using format x1 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is within the height range of n2 starting from n1 height thresholds, and using format x2 for use in performing random access and/or avoiding conflict or collision with at least one other wireless communication device when the current height is within the height range of n3 starting from n1 or n1 plus n2 height thresholds. The same combination mapping method between height information and the other parameter (e.g., cyclic shift values, logical root indexes, etc. ) can be applied. For other RACH parameters not indicated in the third higher layer signaling, consistency with the legacy RACH parameter (e.g., the first higher layer signaling) can be maintained/kept.

In some implementations, the wireless communication device may receive the RACH configurations from the wireless communication node, after the wireless communication device rises to at least a specific height or a height associated with the one or more height information, such as satisfying the height information.

In some implementations, the one or more height information can be configured as an absolute height, such as the height relative to the sea level. In some implementations, the one or more height information can be configured as a relative height, such as the height difference between the wireless communication device and the surrounding environment (e.g., buildings, peaks, etc. ) . In some implementations, the one or more height information can be configured as an absolute height information and/or one or more reference heights.

In some implementations, the one or more height information can be configured via SIB signaling in initial move/fly stage. In some implementations, the one or more height information can be configured via RRC dedicated signaling to modify the initial parameter. In some implementations, the one or more height information can be configured per cell (e.g., a cell corresponds to a beam) . In some implementations, the one or more height information can be configured per region (e.g., region divided by different longitudes and latitudes, topographic features, administrative areas, etc. ) . The spatial zone where wireless communication devices can move/fly can be determined by the granularity configuration of height information and height information.

In some implementations, a SIB1 may indicate a RACH configuration (e.g., RACH-ConfigGeneric) that is associated with one or more height information (e.g., thresholds or ranges) for the wireless communication device. The RACH configuration may indicate a new specific preamble format parameter (e.g., prach-ConfigurationIndex-HeightThreshold) for the wireless communication device at a height that satisfies/meets the height information. The RACH configuration may indicate a new specific cyclic shift value (e.g., zeroCorrelationZoneConfig-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a new specific msg1 FDM (e.g., msg1-FDM-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a new specific msg1 frequency start (e.g., msg1-FrequencyStart -HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. An example of the indication of the RACH configuration can include the following:

In some implementations, a SIB1 may indicate a RACH configuration, such as with new information element (IE) , e.g., RACH-ConfigDedicated-HeightThrehsold, that is associated with one or more height information (e.g., thresholds or ranges) for the wireless communication device. The RACH configuration may indicate one or more height thresholds for the wireless communication device, e.g., integers 0, 1, 2, 3, 4, etc., corresponding to height thresholds of 30 meters, 50 meters, 100 meters, 300 meters, and/or 500 meters, etc., respectively. The RACH configuration may indicate a preamble format (e.g., prach-ConfigurationIndex-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a cyclic shift value (e.g., zeroCorrelationZoneConfig-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a msg1 FDM (e.g., msg1-FDM-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a msg1 frequency start (e.g., msg1-FrequencyStart -HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a type of restricted sets (e.g., restrictedSetConfig-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. The RACH configuration may indicate a preamble root index value (e.g., prach-RootSequenceIndex-HeightThreshold) for the wireless communication device at a height that satisfies the height threshold. An example of the IE associated with the one or more height information of the RACH configuration can include the following:

While various embodiments of the present solution have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Likewise, the various diagrams may depict an example architectural or configuration, which are provided to enable persons of ordinary skill in the art to understand example features and functions of the present solution. Such persons would understand, however, that the solution is not restricted to the illustrated example architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, as would be understood by persons of ordinary skill in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described illustrative embodiments.

It is also understood that any reference to an element herein using a designation such as “first, ” “second, ” and so forth does not generally limit the quantity or order of those elements. Rather, these designations can be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed, or that the first element must precede the second element in some manner.

Additionally, a person having ordinary skill in the art would understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits and symbols, for example, which may be referenced in the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

A person of ordinary skill in the art would further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two) , firmware, various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as “software” or a “software module) , or any combination of these techniques. To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure.

Furthermore, a person of ordinary skill in the art would understand that various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, modules, and circuits can further include antennas and/or transceivers to communicate with various components within the network or within the device. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

In this document, the term “module” as used herein, refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purpose of discussion, the various modules are described as discrete modules; however, as would be apparent to one of ordinary skill in the art, two or more modules may be combined to form a single module that performs the associated functions according embodiments of the present solution.

Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present solution. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present solution with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present solution. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Hence, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the scope of this disclosure. Thus, the disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as recited in the claims below.

Claims

A method comprising:

transmitting, by a wireless communication device, a message to a wireless communication node for random access channel (RACH) transmission, determined based on RACH configurations of at least one RACH parameter and associated one or more height information.
The method of claim 1, comprising:

receiving, by the wireless communication device from the wireless communication node, the RACH configurations and the associated one or more height information.
The method of claim 1, wherein the message for the RACH transmission includes at least one of:

a preamble,

a Msg-A for two-step random access procedure, or

a Msg-3.
The method of claim 1, wherein the at least one RACH parameter comprises a parameter or a set of multiple parameters for use in performing random access or avoiding conflict or collision with at least one other wireless communication device.
The method of claim 1, wherein the at least one RACH parameter comprises an indication of at least one of:

the one or more height information,

one or a set of preamble formats,

one or a set of physical random access channel (PRACH) configuration indexes,

one or a set of PRACH occasions (ROs) or resources,

one or a set of cyclic shift values,

one or a set of logical root indexes,

one or more types of restricted sets, or

one or a set of cyclic shift indexes.
The method of claim 2, wherein receiving the RACH configurations comprises receiving the RACH configurations via at least one of a first higher layer signaling, a second higher layer signaling, or a third higher layer signaling to indicate RACH parameters associated with the one or more height information.
The method of claims 1, 5, or 6, wherein the at least one RACH parameter is configured by the first higher layer signaling, and the associated one or more height information is configured by the second higher layer signaling.
The method of claims 1, 5, or 6, wherein the at least one RACH parameter and the associated one or more height information are jointly configured by the third higher layer singaling including at least one of:

the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, height information} ,

the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, RACH parameter, height information} ,

the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, height information, height information} , or

the at least one RACH parameter and the associated one or more height information are configured in pair {RACH parameter, RACH parameter, height information, height information, height information} .
The method of any one of claims 1-8, wherein the one or more height information are configured as at least one of:

a single value,

at least two values,

a range applicable to different RACH parameters,

a reference height applicable to different RACH parameters, or

a threshold applicable to different RACH parameters.
The method of claims 8 or 9, wherein the one or more height information comprise at least one of:

an absolute height,

a relative height relative to a surrounding environment, or

an absolute height threshold and one or more reference heights.
The method of any one of claims 1-10, wherein the one or more height information comprise at least one of:

one or more height information configured per cell, or

one or more height information configured per region.
The method of claim 5, wherein the at least one RACH parameter comprises:

the one or a set of preamble format and the one or a set of ROs or resources; or

the one or a set of cyclic shift values and the one or a set of logical root indexes.
The method of claim 1, comprising:

receiving, by the wireless communication device from the wireless communication node, the RACH configurations via at least one of: a medium access control (MAC) signaling, a radio resource control (RRC) signaling, a system information block (SIB) signaling, or other higher layer signalings.
The method of claim 1, comprising:

receiving, by the wireless communication device from the wireless communication node, the RACH configurations, after the wireless communication device rises to at least a specific height or a height associated with the one or more height information.
The method of claim 1, comprising:

receiving, by the wireless communication device from the wireless communication node, the RACH configurations, each of the RACH configurations comprising at least one RACH parameter that is configured according to a corresponding height information;

determining, by the wireless communication device, a current height of the wireless communication device; and

identifying, by the wireless communication device, one of the RACH configurations, with a corresponding height information that is higher or lower than the current height.
The method of claim 5, wherein the one or a set of cyclic shift values comprise a cyclic shift value that is a smallest of a plurality of cyclic shift values, or comprise a cyclic shift value that is smaller than at least one other cyclic shift value.
The method of claim 5, wherein the one or a set of root index values comprise a logical root index value that is smallest from a plurality of logical root index values, or comprise a logical root index value that is largest from the plurality of logical root index values.
The method of claim 5, comprising at least one of:

generating, by the wireless communication device, at least one preamble sequence according to at least one of the one or a set of preamble formats, the one or a set of PRACH configuration indexes, the one or a set of logical root index values, the one or a set of cyclic shift values or the type of restricted sets; or

transmitting, by the wireless communication device, a preamble on a specific RO based on the at least one RACH configuration and whether the wireless communication device is at a height that meets the one or more height information,

wherein the at least one RACH configuration comprises at least one of the one or a set of PRACH configuration indexes, the one or a set of ROs, or the one or a set of PRACH resources at a height information.
A method comprising:

receiving, by a wireless communication node, a message from a wireless communication device for random access channel (RACH) transmission, determined based on RACH configurations of at least one RACH parameter and associated one or more height information.
A non-transitory computer readable medium storing instructions, which when executed by at least one processor, cause the at least one processor to perform the method of any one of claims 1-19.
An apparatus comprising:

at least one processor configured to perform the method of any one of claims 1-19.