Multiplexing and diversity for multi-aircraft emergency message relay

Abstract

A method of wireless communication by an aircraft-based device includes receiving a dynamic relay identification (ID). The method also includes communicating a discovery signal using a resource mapped to the relay ID. The method also includes communicating a response signal using the resource mapped to the relay ID. A method for wireless communication by a network device includes estimating a location of each of a plurality of aircraft-based devices. The method further includes sending a dynamic relay identification (ID) to each of the aircraft-based devices based on the respective estimated location relative to the out-of-coverage area.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and more particularly to resource multiplexing and transmit diversity for multi-aircraft emergency message relaying. Background Art

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard issued by the Third Generation Partnership Project (3GPP). Narrowband (NB) Internet of Things (IoT) and enhanced machine type communication (eMTC) are sets of enhancements to LTE for machine type communication.

[0003] A wireless communication network may include multiple base stations (BSs) that may support communications for multiple user equipments (UEs). User equipments (UEs) may communicate with base stations (BSs) via downlinks and uplinks. Downlinks (or forward links) refer to the communication link from a BS to a UE, while uplinks (or reverse links) refer to the communication link from a UE to a BS. As will be described in more detail, a BS may be referred to as a Node B, an evolved Node B (eNB), a gNB, an access point (AP), a radio head, a transmit and receive point (TRP), a new radio (NR) BS, a 5G Node B, etc.

[0004] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate at city, country, region, and even global levels. New Radio (NR) (which may also be referred to as 5G) is an enhancement set of the LTE mobile standard released by the Third Generation Partnership Project (3GPP). NR is designed to better integrate with other open standards by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation, so as to better support mobile broadband Internet access. Summary of the invention

[0005] In various aspects of the present disclosure, a method for wireless communication by an aircraft-based device includes receiving a dynamic relay identification (ID). The method also includes communicating a discovery signal using a resource mapped to the relay ID. The method also includes communicating a response signal using the resource mapped to the relay ID.

[0006] In other aspects of the present disclosure, a method for wireless communication by a network device includes estimating a location of each of a plurality of aircraft-based devices. The method also includes sending a dynamic relay identification (ID) to each of the plurality of aircraft-based devices based on the respective estimated location relative to an out-of-coverage area.

[0007] Other aspects of the present disclosure relate to a device. The device has a memory and one or more processors coupled to the memory. The processor is configured to receive a dynamic relay identification (ID). The processor is also configured to communicate a discovery signal using resources mapped to the relay ID. The processor is further configured to communicate a response signal using resources mapped to the relay ID.

[0008] Still other aspects of the present disclosure relate to an apparatus. The apparatus has a memory and one or more processors coupled to the memory. The processor is configured to estimate the position of each of a plurality of aircraft-based devices. The processor is further configured to send a dynamic relay identification (ID) to each of the plurality of aircraft-based devices based on a corresponding estimated position relative to an out-of-coverage area.

[0009] Aspects generally include methods, apparatus, systems, computer program products, non-transitory computer readable media, user equipment, base stations, wireless communication devices, and processing systems as generally described with reference to and as illustrated in the accompanying drawings and description.

[0010] The features and technical advantages of examples according to the present disclosure have been outlined quite broadly above so that the following specific embodiments may be better understood. Additional features and advantages will be described. The disclosed concepts and specific examples may be easily used as a basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent constructions do not depart from the scope of protection of the appended claims. The characteristics of the disclosed concepts, both in terms of their organization and method of operation, and the associated advantages will be better understood by considering the following description in conjunction with the accompanying drawings. Each of the drawings is provided for the purpose of illustration and description and not as a definition of limitations of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order that the features of the present disclosure may be understood in detail, a more specific description may be made with reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain aspects of the present disclosure and therefore should not be considered as limiting the scope thereof, as the description may allow for other equally effective aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0012] Figure 1 An example wireless communication system supporting emergency messaging using mobile relays in accordance with aspects of the present disclosure is illustrated.

[0013] Figure 2 An example wireless communication system supporting emergency messaging using mobile relays in accordance with aspects of the present disclosure is illustrated.

[0014] Figure 3 An example wireless communication system supporting emergency messaging using mobile relays in accordance with aspects of the present disclosure is illustrated.

[0015] Figure 4 is a diagram illustrating multiple aircraft covering the same out-of-cellular coverage area according to aspects of the present disclosure.

[0016] Figure 5 is a diagram illustrating relay identification (ID)-based communication according to aspects of the present disclosure.

[0017] Figure 6 is a diagram illustrating aircraft synchronization according to aspects of the present disclosure.

[0018] Figure 7 is a block diagram illustrating a time domain guard gap according to aspects of the present disclosure.

[0019] Figure 8 is a block diagram illustrating frequency domain guard gaps according to aspects of the present disclosure.

[0020] Fig. 9 is a flow chart illustrating an example process performed, for example, by an aircraft-based device in accordance with various aspects of the present disclosure.

[0021] Fig.10 is a flow chart illustrating an example process, for example, performed by a network device, according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0022] The following is a more comprehensive description of various aspects of the present disclosure with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms, and should not be construed as being limited to any specific structure or function presented throughout the present disclosure. Instead, these aspects are provided so that the present disclosure will be thorough and complete, and the scope of protection of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings, those skilled in the art should recognize that the scope of the present disclosure is intended to cover any aspect of the present disclosure, whether the aspect is implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect. For example, a device or a method can be implemented using any number of aspects described. In addition, the scope of the present disclosure is intended to cover such devices or methods that are practiced using other structures, functionality, or structures and functionality as a supplement to the various aspects of the present disclosure described or in addition. It should be understood that any aspect of the present disclosure disclosed can be embodied by one or more elements of the claims.

[0023] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using hardware, software, or a combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0024] It should be noted that although various aspects may be described using terms commonly associated with 5G and later wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations (such as and including 3G and / or 4G technologies).

[0025] Various aspects of the present disclosure relate to improved methods, systems, devices, and apparatuses for supporting emergency messaging using mobile relays. In general, the described techniques provide for a first user equipment (UE) outside the coverage area of ​​a network entity (e.g., without cellular coverage) to send an emergency message to a second UE (e.g., an aircraft UE) for relaying to the network entity. For example, the first UE may broadcast a first emergency message indicating a request for relaying a second emergency message to one or more network entities according to a beam scanning process. A second UE that may be associated with an aircraft may receive the first emergency message and send a feedback message in response to the first emergency message. In some cases, the feedback message may include an indication that the second UE communicates with or is able to communicate with the network entity through an air-to-ground (ATG) wireless communication network or a satellite entity, an indication of a resource set for sending a second emergency message, or both. The first UE may receive the feedback message, and may unicast a second emergency message to the second UE based on receiving the feedback message (e.g., via an indicated resource set). The second UE may receive the second emergency message and send an indication of the first emergency message, the second emergency message, or both to the network entity.

[0026] Throughout this disclosure, an aircraft (eg, the second UE in the above paragraph) is referred to as a UE for ease of explanation. However, it should be noted that an aircraft may be a UE, a base station, an IAB device, a relay, an intelligent repeater, or any other such device.

[0027] In some cases, the second UE may send the indication directly to the network entity, while in some other cases, the second UE may send the indication to the third UE, and the third UE may send the indication to the network entity. In addition, the second UE may send a second feedback message to the first UE based on receiving the second emergency message, and the first UE may suppress sending additional emergency messages based on the second feedback message.

[0028] Aspects of the disclosure are first described in the context of a wireless communication system. Aspects of the disclosure are then described in the context of a collaborative emergency messaging process and process flow. Aspects of the disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow diagrams related to emergency messaging using mobile relays.

[0029] Figure 1An example of a wireless communication system 100 supporting emergency messaging using mobile relays according to one or more aspects of the present disclosure is illustrated. The wireless communication system 100 may include one or more network entities 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, a new radio (NR) network, or a network operating according to other systems and radio technologies (including future systems and radio technologies not explicitly mentioned herein).

[0030] The network entities 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may include devices in different forms or with different capabilities. In various examples, the network entities 105 may be referred to as network elements, mobility elements, radio access network (RAN) nodes, or network equipment, among other nomenclature. In some examples, the network entities 105 and the UE 115 may communicate wirelessly via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, the network entity 105 may support a coverage area 110 (e.g., a geographic coverage area) within which the UE 115 and the network entity 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area within which the network entity 105 and the UE 115 may support signal communications according to one or more radio access technologies (RATs).

[0031] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or stationary and mobile at different times. The UEs 115 may be devices in different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. The described UEs 115 may be able to communicate with various types of devices, such as Figure 1 Communicate with other UEs 115 or network entities 105) as shown.

[0032] As described, a node of the wireless communication system 100 (which may be referred to as a network node or a wireless node) may be a network entity 105 (e.g., any network entity described herein), a UE 115 (e.g., any UE described herein), a network controller, an apparatus, a device, a computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described. For example, the node may be a UE 115. As another example, the node may be a network entity 105. As another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a UE 115. In another aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a network entity 105. In other aspects of this example, the first node, the second node, and the third node may be different relative to these examples. Similarly, references to UE 115, network entity 105, apparatus, device, computing system, etc. may include disclosure of UE 115, network entity 105, apparatus, device, computing system, etc. as nodes. For example, a disclosure that UE 115 is configured to receive information from network entity 105 also discloses that the first node is configured to receive information from a second node.

[0033] In some examples, the network entities 105 may communicate with the core network 130, or communicate with each other, or both. For example, the network entities 105 may communicate with the core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3 or other interface protocols). In some examples, the network entities 105 may communicate with each other through the backhaul communication link 120 (e.g., according to X2, Xn or other interface protocols) directly (e.g., directly between each network entity 105) or indirectly (e.g., via the core network 130). In some examples, the network entities 105 may communicate with each other via the midhaul communication link 162 (e.g., according to the midhaul interface protocol) or the fronthaul communication link 168 (e.g., according to the fronthaul interface protocol) or any combination thereof. The backhaul communication link 120, the midhaul communication link 162, or the fronthaul communication link 168 may be or include one or more wired links (e.g., electrical links, optical fiber links), one or more wireless links (e.g., radio links, wireless optical links), etc. or various combinations thereof. UE 115 may communicate with core network 130 via communication link 155 .

[0034] One or more of the described network entities 105 may include or may be referred to as a base station 140 (e.g., a transceiver base station, a radio base station, an NR base station, an access point, a radio transceiver, a Node B, an evolved Node B (eNB), a next generation Node B, or a Gigabit Node B (any of which may be referred to as a gNB), a 5G NB, a next generation eNB (ng-eNB), a Home Node B, a Home Evolved Node B, or other suitable terminology). In some examples, the network entity 105 (e.g., a base station 140) may be implemented in an aggregated (e.g., monolithic, stand-alone) base station architecture, which may be configured to utilize a protocol stack that is physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as a base station 140).

[0035] In some examples, the network entity 105 may be implemented in a disaggregated architecture (e.g., a disaggregated base station architecture, a disaggregated RAN architecture) that may be configured to utilize a protocol stack that is physically or logically distributed between two or more network entities 105, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, the network entity 105 may include one or more of the following: a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., a near real-time RIC (near RT RIC), a non-real-time RIC (non-RT RIC)), a service management and orchestration (SMO) 180 system, or any combination thereof. The RU 170 may also be referred to as a radio head, a smart radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmit receive point (TRP). One or more components of the network entity 105 in the decomposed RAN architecture may be co-located, or one or more components of the network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 of the decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), and / or virtual RU (VRU)).

[0036] The functional split between CU 160, DU 165, and RU 170 is flexible and may support different functionalities, depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at CU 160, DU 165, or RU 170. For example, a functional split of a protocol stack may be employed between CU 160 and DU 165 such that CU 160 may support one or more layers of a protocol stack and DU 165 may support one or more different layers of a protocol stack. In some examples, CU 160 may host higher protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functionality and signaling (e.g., radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP)). The CU 160 may be connected to one or more DUs 165 or RUs 170, and the one or more DUs 165 or RUs 170 may host lower protocol layers, such as layer 1 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and may each be at least partially controlled by the CU 160. Additionally or alternatively, a functional split of the protocol stack may be employed between the DU 165 and the RU 170, such that the DU 165 may support one or more layers of the protocol stack, and the RU 170 may support one or more different layers of the protocol stack. The DU 165 may support one or more different cells (e.g., via one or more RUs 170). In some cases, the functional split between CU 160 and DU 165 or between DU 165 and RU 170 can be within the protocol layer (e.g., some functions of the protocol layer can be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer are performed by different ones of CU 160, DU 165, or RU 170). CU 160 can be further functionally split into CU control plane (CU-CP) and CU user plane (CU-UP) functions. CU 160 can be connected to one or more DUs 165 via midhaul communication links 162 (e.g., F1, F1-c, F1-u), and DU 165 can be connected to one or more RUs 170 via fronthaul communication links 168 (e.g., open fronthaul (FH) interface). In some examples, midhaul communication link 162 or fronthaul communication link 168 may be implemented based on interfaces (eg, channels) between layers of a protocol stack supported by respective network entities 105 that communicate over those communication links.

[0037] In a wireless communication system (e.g., wireless communication system 100), infrastructure and spectrum resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to a core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB nodes 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as donor entities or IAB donors. One or more DUs 165 or one or more RUs 170 may be controlled in part by one or more CUs 160 associated with a donor network entity 105 (e.g., a donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate with one or more additional network entities 105 (e.g., IAB nodes 104) via supported access and backhaul links (e.g., backhaul communication links 120). The IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a coupled IAB donor's DU 165. The IAB-MT may include an independent set of antennas for relaying communications with the UE 115, or may share the same antennas of the IAB node 104 (e.g., of the RU 170) for access via the DU 165 of the IAB node 104 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, the IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., the IAB node 104 and the UE 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of the IAB node 104) may be configured to operate according to the techniques described herein.

[0038] Where the described techniques are applied to the context of a decomposed RAN architecture, one or more components of the decomposed RAN architecture may be configured to support emergency messaging using mobile relays as described. For example, some operations described as being performed by a UE 115 or a network entity 105 (e.g., a base station 140) may additionally or alternatively be performed by one or more components of the decomposed RAN architecture (e.g., an IAB node 104, a DU 165, a CU 160, a RU 170, a RIC 175, and a SMO 180).

[0039] 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 term, where a "device" may also be referred to as a unit, a station, a terminal, or a client, etc. UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or may be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be implemented in various objects such as appliances or vehicles, meters, etc.

[0040] The UE 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as network entities 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc. Figure 1 shown.

[0041] The UE 115 and the network entity 105 may wirelessly communicate with each other via one or more communication links 125 (e.g., access links) on one or more carriers. The term "carrier" may refer to a set of RF spectrum resources having a physical layer structure defined to support the communication link 125. For example, a carrier for the communication link 125 may include a portion of an RF spectrum band (e.g., a bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, and NR). Each physical layer channel may 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 may support communications with the UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, the UE 115 may be configured to have multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used for both frequency division duplex (FDD) and time division duplex (TDD) component carriers. Communication between the network entity 105 and other devices may refer to communication between these devices and any portion (e.g., entity, sub-entity) of the network entity 105. For example, the terms "send," "receive," or "communicate" when referring to the network entity 105 may refer to any portion of a network entity 105 (e.g., base station 140, CU 160, DU 165, RU 170) of a RAN communicating with another device (e.g., directly or via one or more other network entities 105).

[0042] The signal waveform transmitted by the carrier may include 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 technology, a resource element may refer to a resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and the subcarrier spacing may be inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both), so that the more resource elements a device receives and the higher the order of the modulation scheme, the higher the data rate of the device may be. Wireless communication resources may refer to a combination of RF spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial resources may increase the data rate or data integrity used for communication with UE 115.

[0043] The time interval of the network entity 105 or the UE 115 may be expressed as a multiple of a basic time unit, which may be, for example, a sampling period T s =1 / (Δf max ·N f ) seconds, 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. Time intervals of communication resources may be organized according to radio frames, each radio frame having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0044] 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 into subframes (e.g., in the time domain), and each subframe may be further divided into a certain number of 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 a certain number of symbol periods (e.g., depending on the length of the cyclic prefix appended in front of each symbol period). In some wireless communication systems 100, the time slot may be further divided into multiple micro-time slots containing one or more symbols. Excluding 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 operating frequency band.

[0045] A subframe, a time slot, a mini-time slot, or a 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)).

[0046] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier using, for example, 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)) of a physical control channel may be defined by a set of symbol periods and may extend across a system bandwidth of a carrier or a subset of that system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more UEs in UE 115 may monitor or search a control region to obtain control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate may refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 , and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0047] The network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hot spots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used to communicate with the network entity 105 (e.g., via a carrier), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other cell identifier) ​​used to distinguish adjacent cells. In some examples, a cell may also refer to a coverage area 110 or a portion of a coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors such as the capabilities of the network entity 105, such cells may range from smaller areas (e.g., structures, subsets of structures) to larger areas. For example, a cell may be or may include a building, a subset of a building, or an external space between or overlapping coverage areas 110, and the like.

[0048] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access to UEs 115 that have service subscriptions with a network provider that supports the macro cell. Small cells may be associated with lower power network entities 105 (e.g., lower power base stations 140) 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 that have service subscriptions with a network provider, 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 network entity 105 may support one or more cells, and may also use one or more component carriers to support communications on one or more cells.

[0049] In some examples, the network entities 105 (e.g., base stations 140, RUs 170) may be mobile and thus provide communication coverage for mobile coverage areas 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of network entities 105 provide coverage for various coverage areas 110 using the same or different radio access technologies.

[0050] The wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC). UE 115 may be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communication may include private communication or group communication, and may be supported by one or more services (such as push-to-talk, video, or data). Support for ultra-reliable, low-latency functions may include prioritization of services, and such services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency may be used interchangeably herein.

[0051] In some examples, a UE 115 may be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., according to a peer-to-peer (P2P), D2D, or sidelink protocol). In some examples, one or more UEs 115 in a group that are performing D2D communications may be within a coverage area 110 of a network entity 105 (e.g., a base station 140, a RU 170), which may support aspects of such D2D communications as configured or scheduled by the network entity 105. In some examples, one or more UEs 115 in such a group may be outside of the coverage area 110 of the network entity 105, or may otherwise be unable or not configured to receive transmissions from the network entity 105. In some examples, a group of UEs 115 communicating via D2D communications may support a one-to-many (1:M) system in which each UE 115 transmits to each of the other UEs 115 in the group. In some examples, network entity 105 may facilitate scheduling of resources for D2D communications. In some other examples, D2D communications may be performed between UEs 115 without involving network entity 105.

[0052] In some systems, the D2D communication link 135 can be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, the vehicles can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these items. The vehicles can 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 the V2X system can communicate with roadside infrastructure (such as roadside units) using vehicle-to-network (V2N) communication, or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170), or both.

[0053] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) for managing access and mobility and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) for routing packets or interconnecting to an external network. The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management of UE 115 served by a network entity 105 (e.g., a base station 140) associated with the core network 130. User IP packets may be delivered through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to the IP service 150 of one or more network operators. IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0054] The wireless communication system 100 may operate using one or more frequency bands that may be in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally speaking, 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 (which may be referred to as clusters), but these waves may be sufficient to penetrate structures so that macro cells provide services to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using smaller frequencies and longer wavelengths of the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0055] The wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, the wireless communication system 100 may employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in unlicensed bands such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed RF spectrum band, devices such as the network entity 105 and the UE 115 may employ carrier sensing for conflict detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration combined with component carriers operating in a licensed band (e.g., LAA). Operations in the unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, and the like.

[0056] The network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of the network entity 105 or UE 115 may be located in 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, antennas or antenna arrays associated with the network entity 105 may be located at different geographical locations. The network entity 105 may have an antenna array having a collection of multiple rows and columns of antenna ports that the network entity 105 can use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals sent via the antenna ports.

[0057] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a network entity 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 conveyed via antenna elements of an antenna array so that some signals propagating in a particular direction relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals conveyed 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 these antenna elements may be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or the receiving device or relative to some other direction).

[0058] The network entity 105 or UE 115 may use beam scanning techniques as part of a beamforming operation. For example, the network entity 105 (e.g., base station 140, RU 170) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be sent multiple times by the network entity 105 along different directions. For example, the network entity 105 may send signals according to different sets of beamforming weights associated with different transmission directions. Transmissions along different beam directions may be used to identify (e.g., by a transmitting device (such as network entity 105), or by a receiving device (such as UE 115)) beam directions for later transmission or reception by the network entity 105.

[0059] Some signals, such as data signals associated with a particular receiving device, may be sent by a transmitting device (e.g., transmitting network entity 105, transmitting UE 115) along a single beam direction (e.g., a direction associated with a receiving device (such as receiving network entity 105 or receiving UE 115)). In some examples, the beam direction associated with the transmission along the single beam direction may be determined based on signals sent along one or more beam directions. For example, UE 115 may receive one or more of the signals sent by network entity 105 along different directions, and may report to network entity 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0060] In some examples, transmission by a device (e.g., by network entity 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or beamforming to generate a combined beam for transmission (e.g., from network entity 105 to UE 115). UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured set of beams across a system bandwidth or one or more subbands. Network entity 105 may send reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)), which may or may not be precoded. UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., multi-panel codebook, linear combination codebook, port selection codebook). Although these techniques are described with reference to signals sent along one or more directions by a network entity 105 (e.g., base station 140, RU 170), UE 115 may use similar techniques to send signals multiple times along different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115), or to send signals along a single direction (e.g., to send data to a receiving device).

[0061] A receiving device (e.g., UE 115) may perform receiving operations according to multiple receiving configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a receiving device (e.g., network entity 105). For example, the receiving device may perform reception according to multiple receiving directions by: receiving via different antenna subarrays, processing the received signals according to different antenna subarrays, receiving according to different receiving beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing the received signals according to different receiving beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receiving configurations or receiving directions. In some examples, the receiving device may use a single receiving configuration to receive along a single beam direction (e.g., when receiving a data signal). A single receive configuration may be aligned along a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0062] UE 115 and network entity 105 may support retransmission of data to increase the likelihood of data being successfully received. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood of correctly receiving data through a communication link (e.g., communication link 125, D2D communication link 135). HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, a device may support simultaneous slot HARQ feedback, wherein the device may provide HARQ feedback in a specific time slot for data received in a previous symbol in the time slot. In some other examples, the device may provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0063] Some wireless communication systems may support emergency (e.g., SOS) messaging from user equipment (UE) such as ground UE. For example, when the ground UE is outside the cellular coverage area of ​​the network entity (e.g., the ground UE does not have cellular coverage), the ground UE may support emergency messaging with an aircraft UE communicating through an air-to-ground (ATG) wireless communication node. That is, the ground UE may send an emergency message to the aircraft UE, and the aircraft UE may relay the emergency message to the network entity. In some cases, in order to initiate communication with the ground UE, the aircraft UE may send discovery signaling. However, sending discovery signaling may cause interference to ground communications. In some other cases, the ground UE may send repetitions of emergency messages for the aircraft UE to receive. In such cases, the signaling repetition of the emergency message by the ground UE may cause increased power consumption at the ground UE. Throughout this disclosure, the aircraft is referred to as a UE for ease of explanation. However, it should be noted that the aircraft may be a UE, a base station, an IAB device, a relay, an intelligent repeater, or any other such device.

[0064] Two-part emergency message transmission and reception can be used with mobile relay. For example, a first UE may broadcast a first emergency message indicating a request for relaying a second emergency message to a network entity. A second UE (e.g., a relay node) may receive the first emergency message and send a feedback message in response to the first emergency message, the feedback message indicating that the second UE can be used to relay the second emergency message. In some cases, the feedback message may include an indication that the second UE can relay the second emergency message through the ATG wireless communication network. Additionally or alternatively, the feedback message may include an indication of resources for sending the second emergency message. The first UE may receive the feedback message and unicast the second emergency message to the second UE (e.g., via the indicated resources). The second UE may receive the second emergency message and directly or via an additional UE (e.g., a relay node) to relay an emergency message (e.g., a first emergency message, a second emergency message, or both) to the network entity.

[0065] Figure 2 An example of a wireless communication system 200 supporting emergency messaging using mobile relays according to one or more aspects of the present disclosure is illustrated. The wireless communication system 200 may be implemented as shown in FIG. Figure 1 Various aspects of the wireless communication system 100 described herein may be implemented by various aspects of the wireless communication system. For example, the wireless communication system 200 may include a network entity 105-a, a network entity 105-b, and a network entity 105-c, which may represent the network entities described herein (including the network entities described herein). Figure 1 ) of the network entity 105. In addition, the wireless communication system 200 may include UE 115-a, UE 115-b, UE 115-c, and UE 115-d, which may represent the network entity 105 as described (including reference Figure 1 )'s example of UE 115.

[0066] The network entities 105 may each correspond to a coverage area 110, such as coverage area 110-a, coverage area 110-b, and coverage area 110-c, which may be as described in reference to FIG. Figure 1 1. For example, network entity 105-a may serve coverage area 110-a, network entity 105-b may serve coverage area 110-b, and network entity 105-c may serve coverage area 110-c. Network entity 105 may communicate with UE 115 via one or more communication links 125, such as communication link 125-a, communication link 125-b, communication link 125-c, communication link 125-d, communication link 125-e, communication link 125-f, and communication link 125-g, which may be represented as shown in reference Figure 1An example of the communication link 125. In some examples, UE 115 can be an example of an aircraft or other wireless device (e.g., a drone, a vehicle, or other example of a wireless communication device).

[0067] The wireless communication system 200 can support various types of communications, such as ATG communications. For example, in inland or coastal areas, the network entity 105-a (e.g., a gNB, such as an ATG-gNB) can be on the ground and send communications via an antenna tilted upward toward the UE 115-a. UE 115-a can be an example of an ATG-UE and can receive communications with the antenna pointed downward (e.g., UE 115-a can include an antenna located at the bottom of UE 115-a). For example, the antenna of an aircraft UE 115-a can be mounted on the bottom of the aircraft (e.g., an antenna with beamforming capabilities). Compared to satellite communications using satellites 205, such wireless communications can be relatively low-cost, relatively high throughput, achieve lower latency, or any combination thereof. In some examples, the wireless communication system 200 can support one or more business types (e.g., aircraft passenger communications, air traffic management communications, aircraft monitoring or maintenance communications, air traffic control, etc.). In some cases, one or more traffic types may be presented based on the location of UE 115 (e.g., in-flight passenger communications presented en route during a commercial flight and / or in-flight passenger communications presented during takeoff (e.g., climb) and landing (e.g., descent) during a commercial flight).

[0068] Additionally or alternatively, the wireless communication system 200 may support communications with a satellite 205. For example, the satellite 205 may communicate with a UE 115-d (e.g., where the UE 115-d may be in an ocean area outside of a coverage area 110-c associated with the network entity 105-c). The satellite 205 may communicate with devices in the coverage area 110-d. For example, the network entity 105-c may send or receive communications with the satellite 205, and the satellite 205 may send or receive communications with the UE 115-d via the communication link 125-g.

[0069] In some examples, the wireless communication system 200 may support TDD or FDD communications, including FDD communications in a non-terrestrial network (NTN). In some examples, the wireless communication system 200 may support a relatively large inter-site distance (ISD), a relatively large coverage range, or a combination thereof. For example, in order to control network deployment costs and take into account a large number of flights, a large ISD (e.g., 100 kilometers (km), 200km, or another range) may be achieved. Additionally or alternatively, the distance between the UE 115 and the network entity 105 may be relatively large (e.g., when the aircraft is over the sea, the distance may be greater than 200km), and therefore the wireless communication system 200 (e.g., ATG network) may be configured to provide relatively large cell coverage (e.g., up to 300km cell coverage).

[0070] In some examples, the wireless communication system 200 may support both ATG communications (e.g., ATG networks) and ground NR networks. For example, interference between the ground network and the ATG network may be relatively low, and some operators may deploy the two networks using the same frequency (e.g., 4.8 GHz). In some examples, an ATG terminal (e.g., UE 115) may have a relatively large capacity. For example, an onboard ATG terminal may be relatively more powerful than a mobile device UE 115 (e.g., the terminal may have a higher effective isotropic radiated power (EIRP), a greater transmit power, or a greater onboard antenna gain than some ground UEs 115).

[0071] In some examples, the wireless communication system 200 may support one or more throughput attributes and specifications for NR-ATG communications. In some examples, the wireless communication system 200 may support data rates for each individual device (e.g., 15 megabits per second (Mbps) in the downlink and 7.5 Mbps in the uplink), which may also apply to cell edge devices. In some examples, the wireless communication system 200 may support end-to-end latency (e.g., 10 milliseconds (ms)). In some examples, the wireless communication system 200 may support a certain degree of mobility for UE 115 (e.g., up to 1200 km per hour (km / h)). In some examples, the wireless communication system 200 may support connection density (e.g., 80 personal devices per aircraft, 60 aircraft per 18,000 square kilometers, or another connection density). In some cases, in order to achieve connection density, the wireless communication system 200 may support multiple sectors per cell (e.g., 3 sectors per cell), where each cell may include multiple supported devices (e.g., 20 aircraft). In some examples, the wireless communication system 200 can support a data rate per aircraft (e.g., 1.2 Gigabits per second (Gbps) in the downlink and 600 Mbps in the uplink), which can also be applicable to cell edge devices. In one example, such aircraft can include 400 passengers, and the activation factor is 20%, and there can be 80 personal devices per aircraft.

[0072] In some cases, the wireless communication system 200 may be configured as described to support relatively large cell coverage (e.g., up to 300 km), flight speed (e.g., 1200 km / hour flight speed), coexistence between ATG networks and ground networks, ATG base stations or UE cores and performance thresholds, or any combination thereof. For example, the wireless communication system 200 may support relatively large ISDs (e.g., 100 km to 200 km over land, and up to 300 km of coverage along the coast). Additionally or alternatively, the wireless communication system 200 may support relatively large timing advances (TA) (e.g., a TA value equal to 2 ms at 300 km of coverage) to avoid frequent handovers and inter-cell interference.

[0073] Additionally or alternatively, the wireless communication system 200 may support relatively large per-cell throughputs (e.g., data rates of at least 1 Gbps per aircraft). For example, an aircraft may experience a 1.2 Gbps data rate for downlink communications, and a 600 Mbps data rate for uplink communications. For a cell coverage range of 134 km, such large per-cell throughputs may occur in an airspace with a density of 60 aircraft per 18,000 square kilometers. In situations where the density of aircraft or airspace is high (e.g., congested, such as near a busy airport), the data rate may be reduced, but may still remain at or above the 1 Gbps data rate per aircraft specification.

[0074] Additionally or alternatively, the wireless communication system 200 may support relatively large frequency Doppler shifts (e.g., a line-of-sight (LoS) maximum Doppler shift at 1200 km / h may be approximately 0.77 kHz at 700 MHz, or 3.89 kHz at 3.5 GHz, or 5.33 kHz at 4.8 GHz), relatively large subcarrier spacing (SCS) (e.g., SCS values ​​of 7.5 kHz at 700 MHz, or 30 kHz or 60 kHz at 3.5 GHz, or 60 kHz at 4.8 GHz, assuming that the receiver on the device can tolerate a maximum LoS Doppler shift of approximately 10% of the SCS), relatively short coherence time, relatively fast TA drift, or any combination of these.

[0075] Additionally or alternatively, the wireless communication system 200 may support various CP lengths or waveforms. These may support various propagation scenarios, such as en route, climbing, descending, takeoff, landing, taxiing, or parking of an aircraft. In en route, climbing, and descending propagation scenarios, the signal may decay according to the Rician model due to phase interactions between the propagation paths of the signal. For example, there may be a signal delay of up to 2.5 km for the en route scenario, corresponding to a time delay of 8.33 microseconds (μs). In takeoff, landing, taxiing, and parking propagation scenarios, the signal may decay according to the Rayleigh model due to phase interactions between the propagation paths of the signal. In the climb and descend or takeoff and landing propagation scenarios or both, the signal delay may be comparable to or less than the signal delay en route (e.g., still relatively large). Parking and taxiing delays may be similar to ground-like delays.

[0076] Additionally or alternatively, if frequencies are reused, the wireless communication system 200 may cause interference to ground NR systems. For example, the aircraft transmit beamwidth may become larger (e.g., after 100km to 200km of propagation), thereby affecting a relatively wide ground area. Such interference may be relatively dynamic and non-synchronous when considering the effects of dynamic time division duplex (TDD) and large propagation delays.

[0077] The wireless communication system 200 may communicate according to the UAC protocol. In the NR system, the UAC protocol may allow an operator device (e.g., a network entity 105, etc.) to control access of a subscriber device (e.g., a UE 115, etc.) to a specific NR system or network. Depending on the operator policy, deployment scenario, subscriber profile, available services, or any combination of these, the operator device may use different criteria to determine which access attempts of the subscriber device may be allowed or blocked (e.g., when congestion occurs in the NR system or network). These different criteria (e.g., characteristics, time, location, proximity, interference, or any other criteria) may be associated with various access identities, access categories, or both. Thus, the operator device may classify each access attempt into one or more access identities, access categories, or both. In some cases, the access identity may be associated with the UE 115 subscription type, and the access category may be associated with the UE 115 service (e.g., emergency situation, voice call, etc.) that may trigger the access attempt.

[0078] The wireless communication system 200 may support two-part emergency messages using mobile relay as described. For example, a first UE such as a ground UE 115 may lose cellular coverage and may broadcast a first emergency message indicating a request to relay a second emergency message to the network entity 105. A second UE 115, such as a UE 115- (e.g., an aircraft UE 115) may receive the first emergency message and may send a first feedback message to the ground UE 115 based on receiving the first emergency message. In some cases, the first feedback message may include an indication that the UE 115-a is available for relaying messages, an indication that the UE 115-a is able to communicate through the ATG wireless communication network, an indication of resources for the second emergency message, or any combination thereof. The ground UE 115 may receive the first feedback message and may unicast the second emergency message to the UE 115-a. The UE 115-a may receive the second emergency message and send an indication of an emergency message (e.g., a first emergency message, a second emergency message, or both) to the network entity 105 (such as the network entity 105-a). In some cases, UE 115-a may send an indication of the emergency message directly to network entity 105-a via communication link 125-a. In some other cases, UE 115-a may send an indication of the emergency message to another UE 115 (such as UE 115-b) for additional relaying. For example, UE 115-a may send an indication of the emergency message to UE 115-b via communication link 125-h, and UE 115-b may send an indication of the emergency message to network entity 105-b via communication link 125-b or send an indication of the emergency message to network entity 105-c via communication link 125-c.

[0079] The UE 115 may include a relay identification (ID) module 145. For simplicity, only one UE 115-c is shown as including a relay ID module 145. The relay ID module 145 may receive a dynamic relay identification (ID). The relay ID module 145 may also communicate a discovery signal using resources mapped to the relay ID. The relay ID module 145 may also communicate a response signal using resources mapped to the relay ID.

[0080] The core network 130 or the network entity 105 or any other network device may include a relay ID module 148. For simplicity, only one 105-a is shown as including a relay ID module 148. The relay ID module 148 may estimate the location of each aircraft-based device in a group of aircraft-based devices. The relay ID module 148 may also send a dynamic relay identification (ID) to each aircraft-based device in the aircraft-based devices based on the respective estimated location relative to the out-of-coverage area.

[0081] The controller / processor of the network entity 105, the controller / processor of the UE 115, and / or any other component may perform one or more techniques associated with a dynamic relay ID, as described in more detail elsewhere. For example, the controller / processor of the network entity 105, the controller / processor of the UE 115, and / or any other component may perform or direct, for example, Fig. 9 and Fig.10 processes and / or operations of other processes as described.

[0082] In some aspects, UE 115 and / or network entity 105 may include means for receiving, means for communicating, means for synchronizing, means for relaying, means for computing, means for sending, and means for estimating. Such means may include one or more components of UE 115 or network entity 105.

[0083] Figure 3 An example of a wireless communication system 300 that supports emergency messaging using mobile relays according to one or more aspects of the present disclosure is illustrated. The communication scheme 300 may implement or be implemented by aspects of the wireless communication system 100 and the wireless communication system 200. For example, the wireless communication system 300 may include a network entity 105-d, a UE 115-e, and a UE 115-f. The UE 115-e and the UE 115-f may represent a wireless communication system as described (including reference Figure 1 ) of an example of a UE 115. The network entity 105-d may represent an example of a UE 115 as described (including reference Figure 1 ) is an example of a network entity 105. For example, a UE 115-e may send an emergency message (e.g., an SOS message) according to the described techniques to support interference reduction, power conservation, and service enhancement for emergency messaging transmissions for the UE 115-e.

[0084] Some wireless communication systems may support emergency (e.g., SOS) messaging from UE 115 (such as ground UE 115). For example, when ground UE 115 is outside the cellular coverage of network entity 105, UE 115 may support one or more methods for delivering (e.g., sending) emergency messages. In some cases, ground UE 115 may send emergency messages to satellite entities (e.g., message delivery similar to Iridium satellite). However, ground UE 115 may send emergency messages based on strict antenna and transmission power parameters (e.g., requirements). Thus, ground UE 115 may successfully send emergency messages by pointing one or more antennas at ground UE 115 to satellite entities while sending emergency messages to avoid obstruction (e.g., this may require skilled manual assistance). In addition, ground UE 115 may not be able to send machine type communication (MTC) based on the form factor of ground UE 115.

[0085] In some cases, the ground UE 115 can use the air interface associated with the satellite entity to send an emergency message to the satellite entity. However, not all satellite entities can be associated with the air interface, and thus, the ground UE 115 can attempt to send an emergency message over the air interface, but may not be successful due to lack of coverage from the satellite entity associated with the air interface. In addition, transmitting a satellite associated with the air interface may be associated with a high deployment cost. In other examples, the ground UE may not be able to send a signal with enough power to reach the satellite, which may be far away from the ground UE for a long distance.

[0086] In some cases, the ground UE 115 may send an emergency message to the aircraft UE 115 (e.g., to extend coverage for areas without ground network entities 105). The aircraft UE 115 may cruise at an altitude (e.g., 10 km) that can support LoS propagation of more than 200 km (e.g., and there may be at least one aircraft visible within 50 km to 100 km in most major remote areas). In addition, compared with emergency messaging via a satellite entity, sending emergency messages to the aircraft UE 115 can reduce deployment costs and support reduced human assistance when operating the ground UE 115. In some cases, in order to support emergency messaging, the aircraft UE 115 may continuously broadcast a discovery notification signal covering a wide area, which may cause severe interference to ground communications (e.g., because ground communications share the same frequency as ATG communications). In addition, the aircraft UE 115 may not know the existence of the ground UE 115 (e.g., a remote device outside the coverage). In some other cases, the ground UE 115 may send repetitions of emergency messages, which may result in increased power consumption.

[0087] The technology may support two-part emergency message transmission and reception using mobile relay. In some cases, a UE 115-e (e.g., a ground UE 115) may leave the cellular coverage area of ​​a network entity 105 (e.g., the last ground-based network entity 105) (e.g., leave its range) and may lose cellular coverage (e.g., become a UE 115 outside of cellular coverage). In such a case, the UE 115-e may be configured to broadcast (e.g., send) a first emergency message (e.g., the first part of a two-part emergency message), such as an emergency message 305-a, indicating a request for relaying an emergency message (e.g., when the UE 115-e is outside of cellular coverage). Thus, the UE 115-e may broadcast (e.g., in a PC5 interface) the emergency message 305-a via a broadcast resource set. In some cases, the set of broadcast resources may be configured by the last network entity 105 that will communicate with the UE 115-e before coverage is lost, by a satellite entity (e.g., a satellite communication system), or by a parameter set at the UE 115-e (e.g., pre-configured at the UE 115-e). In addition, the emergency message 305-a may include an indication of an identity for the UE 115-e (e.g., in a dedicated sequence or preamble for emergency messaging). In some cases, the UE 115-e may monitor for feedback messages 310 from a UE 115 (such as a UE 115-f) during a time period (e.g., a configured window) after the transmission of the emergency message 305-a.

[0088] In some cases, the UE 115-e may broadcast the emergency message 305-a via one or more beams 320 (such as beam 320-a and beam 320-b) according to a beam scanning process (e.g., a scheme). In some examples, the beam scanning process may be an inhomogeneous beam scanning process. This may be because UEs associated with aircraft may be located at different angles from ground-based UEs compared to ground-based network entities or other UEs. That is, the UE 115-e may be configured by the last network entity 105 (e.g., via RAN-based signaling or application layer protocol) to send the emergency message 305-a according to an inhomogeneous beam scanning process, where the last network entity 105 is the network entity 105 with which the UE 115-e last (e.g., most recently) communicated before becoming an out-of-cellular coverage UE 115 (e.g., losing coverage from the last network entity 105).

[0089] The non-uniform beam scanning process may include scanning beams having low elevation angles (e.g., less than or equal to 18 degrees), such as beam 320-b having elevation angle 325-b, with a high probability, and scanning beams having high elevation angles (e.g., greater than 18 degrees), such as beam 320-a having elevation angle 325-a, with a low probability. That is, UE 115-e may scan beam 320-b having elevation angle 325-b with increased repetitions compared to beam 320-a having elevation angle 325-a. In addition, the transmit power of a beam having a low elevation angle may be higher than the transmit power of a beam having a high elevation angle (e.g., because an aircraft (such as an aircraft associated with UE 115-f) typically flies between elevation angles of 6 degrees and 18 degrees while having a cell radius of 100 km and an aircraft altitude of 10 km).

[0090] In some cases, UE 115-e may broadcast emergency message 305-a based on aircraft information (e.g., associated with UE 115-f). The aircraft information may include information that may enable UE 115-e to identify one or more UEs 115 (e.g., associated with aircraft information, such as UE 115-f), communicate with one or more UEs 115, determine the location of one or more UEs 115, determine the direction of one or more UEs 115, determine the speed of one or more UEs 115, etc. For example, the aircraft information may include identification information, location information, flight path information, or any combination thereof.

[0091] In some examples, UE 115-e may be configured to send emergency message 305-a based on aircraft information based on an indication of aircraft information included in a control message from the last network entity 105 that will communicate with UE 115-e before losing cellular coverage (e.g., via RAN-based signaling or application layer protocols) or from a satellite entity. As another example, UE 115-e may be configured to send emergency message 305-a based on aircraft information based on one or more parameters at UE 115-e (e.g., the aircraft information may be pre-configured at UE 115-e). Thus, UE 115-e may monitor UE 115 (such as UE 115-f) associated with the aircraft information and may send emergency message 305-a based on the monitoring. That is, when UE 115-f is near (e.g., within a distance threshold) UE 115-e based on aircraft information (e.g., UE 115-f is flying near UE 115-e), UE 115-e can broadcast emergency message 305-a. Conversely, when UE 115-f is not near UE 115-e based on aircraft information, UE 115-e can refrain from broadcasting emergency message 305-a (e.g., UE 115-f can sleep when UE 115-f is not nearby).

[0092] In some cases, the UE 115-e may determine that the aircraft information is valid based on one or more locations of the UE 115-e. In other words, the UE 115-e may determine an initial location (e.g., an initial global navigation satellite system (GNSS) location) of the UE 115-e (e.g., a location where the UE 115-e lost coverage) and a current location (e.g., a current GNSS location) of the UE 115-e. The initial location of the UE 115-e may be the location of the UE 115-e when the UE 115-e received the aircraft information (e.g., from the last network entity or from a satellite entity), the location of the UE 115-e when the UE 115-e lost ground cellular coverage, etc. In addition, the UE 115-e may compare the initial location with the current location to determine a change in location (e.g., a distance moved) and compare the change in location with a distance threshold. In some cases, the UE 115-e may determine that the aircraft information is valid based on the change in location being less than or equal to (e.g., failing to exceed) the distance threshold. Thus, UE 115-g may send emergency message 305-a based on the aircraft information based on the aircraft information being valid. Conversely, UE 115-e may determine that the aircraft information is invalid (e.g., not valid) based on the change in location being greater than (e.g., exceeding) a distance threshold. Thus, UE 115-g may refrain from sending emergency message 305-a based on the aircraft information based on the aircraft information being invalid.

[0093] Additionally or alternatively, the UE 115-e may send the emergency message 305-a according to a periodic timer (e.g., when the aircraft information is invalid). For example, the UE 115-e may be configured to send the emergency message 305-a according to a periodic timer based on an indication of a periodic timer included in a control message from the last network entity 105 that communicated with the UE 115-e before losing cellular coverage (e.g., via RAN-based signaling or an application layer protocol). In some cases, the periodic timer may indicate that the UE 115-g (associated with the aircraft) is listening to specific communication resources for certain types of messages, including emergency messages. In some cases, the UE 115-e may broadcast the emergency message 305-a during an "ON" duration and refrain from broadcasting the emergency message 305-b during an "OFF" duration (e.g., the UE 115-g may sleep during the "OFF" duration). The "ON" duration and the "OFF" duration may be based on periodic "ON" and "OFF" timers for the emergency message 305-a (eg, indicated in the control message).

[0094] UE 115-f (e.g., a relay node) may receive an emergency message 305-a from UE 115-e. In some cases, UE 115-f may identify a dedicated emergency message from a specific emergency indication in the emergency message 305-a. In addition, UE 115-f may send a feedback message 310-a to UE 115-e based on receiving the emergency message 305-a. In some embodiments, UE 115-e may suppress sending additional emergency messages 305-a (e.g., to reduce power consumption) based on receiving the feedback message 310-a. In some cases, UE 115-f may be associated with an aircraft (e.g., an aircraft UE 115). In some other cases, UE 115-f may be a UE 115 (e.g., a ground UE 115) connected to a network entity such as network entity 105-d (e.g., a UE 115 within cellular coverage).

[0095] In some cases, the UE 115-e may be configured to send (e.g., unicast send) a second emergency message (e.g., the second part of a two-part emergency message), such as the emergency message 305-b, which includes emergency information based on the received feedback message 310-a. Thus, the UE 115-e may send (e.g., in a PC5 interface) the emergency message 305-b via a unicast resource set (e.g., a side link resource). In some cases, the unicast resource set may be configured by the last network entity 105 that will communicate with the UE 115-e before losing coverage, by a satellite entity (e.g., a satellite communication system), by a parameter set at the UE 115-e, or based on the feedback message 310-a (e.g., an indication in the feedback message 310-a). In addition, the emergency message 305-b may include an indication of an identity for the UE 115-e.

[0096] In some cases, UE 115-f may send a feedback message 310-b based on receiving an emergency message 305-b. In addition, UE 115-f may send (e.g., relay) an emergency message indication 315 to network entity 105-d, and the emergency message indication 315 is based on emergency message 305-a, emergency message 305-b, or both. That is, UE 115-f may relay emergency message 305-a, emergency message 305-b, or both to network entity 105-d. In some cases, UE 115-f may send an emergency message indication 315 to a satellite entity or another UE 115 (e.g., the UE may relay the emergency message indication 315 to network entity 105-d). In some embodiments, UE 115-e may suppress broadcasting emergency message 305-a, unicasting emergency message 305-b, or both based on receiving feedback message 310-b (e.g., from at least one UE 115, such as UE 115-f).

[0097] Although described in the context of a UE 115-f associated with an aircraft, it should be understood that UE 115-f may be any UE 115 (e.g., a ground UE 115) connected to a network entity 105 such as network entity 105-d (e.g., in a coverage area such as coverage area 110-e).

[0098] As described above, commercial aircraft-based emergency message relay technology can extend coverage for areas without one or more ground base stations. The typical cruising altitude of an aircraft (e.g., 10 km) allows line-of-sight (LoS) propagation over 200 km. Although the density of commercial aircraft in any particular location varies from region to region, overall aircraft coverage is relatively dense during daylight hours. In other words, there may be at least one aircraft visible within 50 km to 100 km in most major remote areas in the United States.

[0099] Multiple aircraft may cover the same out-of-cellular coverage area (also referred to as "out-of-coverage area" for short). Since the trajectories of the aircraft may intersect, the on-off control based on the aircraft Global Navigation Satellite System (GNSS) position from the base station may be complex and / or frequently changed. In UE-initiated discovery, multiple aircraft transmit feedback messages that may interfere with each other. In aircraft-initiated discovery, the transmission of wake-up signals (WUS), synchronization signal blocks (SSBs), and discovery messages may interfere with each other.

[0100] Figure 4 is a diagram illustrating multiple aircraft covering the same out-of-cellular coverage area according to various aspects of the present disclosure. Figure 4 In the example of , multiple relay aircraft 115-a, 115-b, 115-c are all within range of a remote UE 115-e. The remote UE 115-e may send an emergency message (e.g., an SOS message) to any or all of the aircraft 115-a, 115-b, 115-c. Therefore, any or all of the aircraft 115-a, 115-b, 115-c may relay the message to a network entity 105-d, such as an air-to-ground (ATG) base station (e.g., a gNB). Since each of the aircraft 115-a, 115-b, 115-c is in close proximity to each other, transmissions to and from the aircraft 115-a, 115-b, 115-c may cause interference. Various aspects of the present disclosure are intended to reduce this interference. Throughout the present disclosure, an aircraft is referred to as a UE for ease of explanation. However, it should be noted that the aircraft may be a UE, a base station, an IAB device, a relay, a smart repeater, or any other such device.

[0101] Locating an aircraft is a problem. Navigation fixes may include errors. In addition, flight delays and route changes may prevent accurate prediction of the aircraft's position. During US Regional Navigation Type 1 (RNAV 1) departure procedures (DPs) and standard terminal approaches (STARs), an aircraft must maintain a total system error of no more than 1 NM (1.8 km) for 95% of the total flight time. During US Regional Navigation Type 2 (RNAV 2) en-route procedures, an aircraft must maintain a total system error of no more than 2 NM (3.6 km) for 95% of the total flight time. Therefore, signaling for aircraft position reporting is desirable because navigation has km-level errors. Aircraft position reports may report any deviations between the actual aircraft position and the navigation-derived position.

[0102] When multiple aircraft participate in relaying, coordination is required. For example, inter-cell coordination and UE coordination may be specified. When multiple aircraft have a common coverage area on the ground, coordination between aircraft as integrated access and backhaul (IAB) devices or UEs may include inter-cell coordination and UE coordination. Because aircraft are highly mobile, existing techniques alone may not be sufficient. Options for improving coordination include enabling one aircraft within common coverage or scheduling different aircraft to transmit using different resources.

[0103] Presumably, there is little chance of aircraft switching or beam switching during emergency messaging because the messages being relayed are very short (e.g., SOS messages). For example, assuming an aircraft speed of 250 m / s and a ground coverage or footprint of one aircraft is a 50 km circle, the maximum service time is 2*50*1000 / 250=400 seconds.

[0104] Various aspects of the present disclosure propose multiplexing and diversity solutions to avoid interference at the remote UE when multiple relay aircraft transmit discovery signals or feedback. For example, multiplexing directs different aircraft to send different signals, which improves the possibility of discovery. Diversity directs all aircraft to send the same message using different resources, thereby improving the signal-to-noise ratio (SNR) at the remote UE. Both solutions reduce the remote UE search space, thereby saving power at the remote UE. That is, if the remote UE knows where to search, the UE does not need to search all possible resources, and thus can save power when searching.

[0105] According to various aspects of the present disclosure, a relay identification (ID) facilitates multiplexing and diversity techniques for multiple aircraft. For example, an air-to-ground (ATG) base station (e.g., gNB) or satellite equipment assigns a dynamic relay ID to aircraft in the same out-of-coverage area. The indication may be dynamically indicated via a downlink control information (DCI) message, a media access control-control element (MAC-CE), or may be semi-statically indicated via MAC-CE or radio resource control (RRC) signaling.

[0106] In some aspects, different aircraft transmit to the ground using different resources mapped by relay IDs. Resource selection is transparent to the remote UE. The aircraft can use multiplexing or diversity techniques with the selected resources. In addition, the relay ID reduces the search space of the remote UE to a known size. In order to enable communication between the remote UE and multiple aircraft, the remote UE and the multiple aircraft are synchronized with each other.

[0107] Figure 5 is a diagram illustrating communication based on a relay ID according to various aspects of the present disclosure. Figure 5In the example of FIG. 1 , network device 105 - d sends a first relay ID (relay ID 1) to relay aircraft 115 - a. Network device 105 - d also sends a second relay ID (relay ID 2) to relay aircraft 115 - b, and sends a third relay ID (relay ID 3) to relay aircraft 115 - c. Note that network device 105 - d may also be a satellite device, although in FIG. Figure 5 1). Based on a first relay ID (relay ID 1), relay aircraft 115-a communicates with remote UE 115-e via resources (resource 1) mapped to the first relay ID (relay ID 1). Based on a second relay ID (relay ID 2), relay aircraft 115-b communicates with remote UE 115-e via resources (resource 2) mapped to the second relay ID (relay ID 2). Based on a third relay ID (relay ID 3), relay aircraft 115-c communicates with remote UE 115-e via resources (resource 3) mapped to the third relay ID (relay ID 3). The communication may include the sending and / or receiving of discovery signals and / or response signals. Figure 5 In the example, the communication includes sending a discovery signal and / or a response signal to the remote UE 115-e.

[0108] As described above, the relay ID reduces the remote UE search space. In some implementations, the relay ID format is a bit sequence of length log 2N. If different aircraft are directed to transmit using different resources based on conventional UE IDs, base station IDs, or cell IDs, the search space for remote UEs will be large. For example, the New Radio (NR) cell ID has 36 bits (the first 22 to 32 bits are the base station ID, and the last 4 to 14 bits are the local cell ID). The smaller the relay ID, the smaller the search space.

[0109] In various aspects of the present disclosure, a network device (e.g., ATG-gNB or satellite) provides a dynamic relay ID for each aircraft in the same out-of-coverage area. The relay ID may be dynamically indicated via downlink control information (DCI) or MAC-CE, or semi-statically indicated via MAC-CE or RRC signaling. In some implementations, the maximum number of relay IDs is limited by N. The value of N is known to all aircraft and remote UEs. In one example, an aircraft with relay ID n transmits using the nth resource in a resource set of size N. Therefore, the remote UE search space is N×(one aircraft resource range + gap).

[0110] In some aspects, only relay aircraft assigned with a relay ID can transmit signals, such as discovery and feedback signals, to the out-of-coverage area. Aircraft without a relay ID are not allowed to send signals in the out-of-coverage area.

[0111] The synchronization of multiple aircraft with a remote UE will now be described in more detail. When multiple aircraft synchronize to a remote UE, the timing relationship changes. For example, the aircraft may change the timing advance (TA) from the network device to the remote UE. For UE-initiated discovery (where the aircraft first receives a message from the remote UE), the first portion of the signal transmitted by the remote UE may be a simplified synchronization signal block (SSB). The aircraft synchronizes to the UE based on this signal before transmitting a response.

[0112] For aircraft-initiated discovery (where the remote UE location is unknown to the aircraft), the network device may control aircraft signaling. For example, the network device may direct each aircraft to send a discovery signal to the same location or zone in the out-of-coverage area. In response, each aircraft calculates its timing advance (TA) based on its own location for transmission to the indicated ground location (e.g., zone). Each aircraft also calculates a frequency compensation value for the indicated ground location (e.g., zone) based on its position and velocity and / or aircraft direction. The frequency compensation takes into account the Doppler shift experienced due to the movement of the aircraft.

[0113] Figure 6 is a diagram illustrating aircraft synchronization according to aspects of the present disclosure. Figure 6 In the example of FIG. 1 , network device 105 - d sends zone ID information to aircraft 115 - a and 115 - b. The zone ID information indicates zone i. Figure 6 In the example of FIG. 6 , three zones 600 are shown: zone i-1, zone i, and zone i+1. Each zone corresponds to an out-of-coverage area where a remote UE may be located. Each aircraft 115-a, 115-b calculates a timing advance (TA) based on the formula TA=l / c, where l is the distance between the aircraft and the zone (zone i in this example), and c represents the speed of light. Each aircraft 115-a, 115-b also calculates a frequency compensation value based on the following formula: where v is the vehicle velocity, θ is the angle between the velocity direction and the direction toward the zone, and f c is the carrier frequency, and c represents the speed of light.

[0114] According to various aspects of the present disclosure, synchronization of a remote UE with multiple aircraft may be assisted by a relay ID. For example, multiple aircraft may periodically transmit the same preamble in different resources mapped by an assigned relay ID. In these aspects, it is assumed that all aircraft are synchronized to a network device, a GNSS device, or an inter-aircraft network so that all aircraft are synchronized together. In order to facilitate synchronization with a remote UE, an aircraft may add a guard gap between two time or frequency resources to address the high mobility of the aircraft. The time domain guard gap may be obtained by the following exemplary method. For a 10km distance difference from two aircraft to the remote UE, the propagation delay difference is 33.33us less than the symbol duration with a 15KHz subcarrier spacing (SCS). Therefore, one symbol duration of the time domain guard gap will be sufficient. The frequency domain guard gap may be obtained by the following exemplary method. For two aircraft traveling in opposite directions at a maximum speed of 1000km / h, the Doppler shift difference at the remote UE is For example, when the carrier frequency f c =6GHz, the Doppler shift difference is 11.1KHz. Therefore, the subcarrier spacing of the frequency domain guard gap will be sufficient.

[0115] Figure 7 is a block diagram illustrating a time domain guard gap according to various aspects of the present disclosure. Figure 7 In the example of FIG. 7 , a first aircraft with a first relay ID transmits its preamble at time 702. In this example, there is a one symbol guard gap at time 704. After the gap, a second aircraft with a second relay ID transmits its preamble at time 706. Another guard gap is observed at time 708. After the gap at time 708, a third aircraft with a third relay ID transmits its preamble at time 710. By including a time domain guard gap, preambles from different aircraft are less likely to interfere with each other.

[0116] Figure 8 is a block diagram illustrating frequency domain guard gaps according to various aspects of the present disclosure. Figure 8 , a first aircraft with a first relay ID transmits its preamble at frequency 802. In this example, there is a single subcarrier-spaced guard gap at frequency 804. Separated from this gap, a second aircraft with a second relay ID transmits its preamble at frequency 806. Another guard gap is observed at frequency 808. Separated by a frequency gap at frequency 808, a third aircraft with a third relay ID transmits its preamble at frequency 810. By including frequency domain guard gaps, preambles from different aircraft are less likely to interfere with each other.

[0117] The size of the remote UE search space used for synchronization is based on the gap.For example, the window size may be defined as N x (preamble size + gap size), where N is the total number of relay IDs.

[0118] When multiple aircraft utilize code division multiplexing (CDM) to periodically transmit the same preamble in different resources mapped by the assigned relay ID, synchronization of the remote UE with multiple aircraft may also be assisted by the relay ID. When code division multiplexing is employed, time and / or frequency overlap may be allowed. In these aspects, different aircraft may transmit using different orthogonal codes. Code division multiplexing may further reduce the search space of the remote UE. Using code division multiplexing, the remote UE may select one or all aircraft to synchronize with.

[0119] In other aspects, both the aircraft and the remote UE are synchronized to the satellite. In these aspects, the satellite can transmit a synchronization signal (such as SSB) to the ground. The aircraft and the remote UE can then synchronize with the satellite's synchronization signal.

[0120] The network device may indicate the relay ID dynamically. The dynamic indication may be implemented via downlink control information (DCI) or MAC-CE. The dynamic indication may be updated based on the aircraft position report. The network device may also indicate the relay ID semi-statically, for example, using MAC-CE or RRC signaling. The semi-static indication may be based on a predicted position using a planned trajectory of the aircraft.

[0121] Aspects of the present disclosure propose triggers for allocating or recycling relay IDs. The trigger is based on whether the aircraft is entering or leaving a zone (e.g., an out-of-coverage area). Upon entering the zone, the network device allocates a relay ID to the aircraft. Upon leaving the zone, the network device recycles the relay ID. The network device may determine whether the aircraft is entering or leaving a zone based on, for example, the position of the aircraft reported by the aircraft. Based on the position, the network device may calculate whether the aircraft is entering or leaving the zone. The network device may also determine whether the aircraft is entering or leaving the zone based on the reference signal received power (RSRP) reported by the aircraft receiving a beam from a network device covering the out-of-coverage area. Another way to determine whether the aircraft is leaving the zone may be based on a timer corresponding to the route and speed of the aircraft. By knowing when the aircraft enters the zone, the network device may set a timer based on the route and speed of the aircraft to determine when the aircraft will leave the zone.

[0122] The maximum number of relay IDs may be limited to N relay IDs, where the value of N is known to the aircraft and the remote UE. When all N relay IDs have been assigned to the out-of-coverage area, in some aspects, no relay IDs will be assigned to additional aircraft. When an aircraft leaves the out-of-coverage area, its relay ID may be recycled.

[0123] Now discuss the resource allocation for aircraft to UE transmission based on relay ID. Network equipment such as ATG-gNB or satellite can indicate the domain of aircraft multiplexing or diversity, such as time domain, frequency domain or code domain. The network equipment can also indicate the time and / or frequency resource range, gap and total start time and / or start frequency to the aircraft. If there is time and / or frequency overlap between multiple aircraft, the network equipment can indicate the code division multiplexing (CDM) code index to the aircraft.

[0124] Based on the information received from the network device, each aircraft transmits using the resource mapped by its relay ID. In an example implementation of synchronization, each aircraft calculates the start and stop positions of the resource as follows:

[0125] Start: total_start + (range + gap) * (relay_id - 1)

[0126] Stop: Start + Range

[0127] The remote UE should know in advance whether the aircraft uses time division multiplexing (TDM), frequency division multiplexing (FDM) or code division multiplexing (CDM), the time / frequency / code resource range and gap used by the aircraft, and the total number of relay IDs.

[0128] Various aspects of the present disclosure avoid interference from multiple aircraft to remote UEs. Various aspects also reduce the remote UE search space, thereby saving UE power. In addition, the SNR of the remote UE is improved, as is the likelihood of discovery.

[0129] As indicated above, Figures 2 to 8 Provided as an example. Other examples may be relevant to Figures 2 to 8 The examples described are different.

[0130] Fig. 9 900 is a flow chart illustrating an example process 900 performed, for example, by an aircraft-based device in accordance with various aspects of the present disclosure. Example process 900 is an example of resource multiplexing and transmit diversity for multi-aircraft emergency message relay. The operations of process 900 may be implemented by a user equipment (UE) 115, a base station, an IAB device, a relay, a smart repeater, or any other such device.

[0131] like Fig. 9 As shown, in some aspects, process 900 may include receiving a dynamic relay identification ID (block 902). The process may also include synchronizing to a satellite synchronization signal. The process may also include receiving a resource range, a starting resource to enable calculation of resources for communicating a discovery signal, and a code and / or gap duration.

[0132] In some aspects, process 900 may include communicating a discovery signal using resources mapped to a relay ID (block 904). For example, the device may communicate a discovery signal by receiving a discovery signal from a remote UE, such that the device synchronizes with the remote UE based on the discovery signal before sending a response signal. In other examples, the device may communicate a discovery signal by sending a discovery signal toward a zone of an out-of-coverage area, such that the device calculates a timing advance based on the position of the aircraft-based device and the zone, and calculates a frequency compensation based on at least one of: the speed and direction of the aircraft-based device; and the position of the aircraft-based device. The discovery signal may include a first preamble that is identical to a preamble of another aircraft-based device. The device may send a subsequent preamble offset by a time domain guard gap and / or a frequency domain guard gap. In some implementations, the device may send a subsequent preamble that overlaps with the first preamble, and the first preamble and the subsequent preamble have different orthogonal cover codes.

[0133] In some aspects, process 900 may include communicating a response signal using a resource mapped to the relay ID (block 906). The device may also synchronize with a remote user equipment (UE) outside of terrestrial cellular coverage based on the discovery signal and the response signal; and after synchronizing with the remote UE, relaying the emergency message from the remote UE to the network device.

[0134] Fig.10 is a flow chart illustrating an example process 1000 performed, for example, by a network device in accordance with various aspects of the present disclosure. The example process 1000 is an example of resource multiplexing and transmit diversity for multi-aircraft emergency message relaying. The operations of process 900 may be implemented by a network device 105-d.

[0135] like Fig.10 As shown, in some aspects, process 1000 may include estimating a location of each of a plurality of aircraft-based devices (block 1002). The device may estimate the location of each of the aircraft-based devices based on a predicted trajectory of each of the plurality of aircraft-based devices. In other aspects, the device may estimate the location of each of the aircraft-based devices based on reporting information from each of the plurality of aircraft-based devices. The reporting information may include at least one of the following: the location of the aircraft-based device, a reference signal received power (RSRP) of a beam received from a network device, and timer information.

[0136] In some aspects, process 1000 may include sending a dynamic relay identification (ID) to each of the plurality of aircraft-based devices based on a respective estimated location relative to an out-of-coverage area. (Block 1004). The device may receive an emergency message relayed via at least one of the aircraft-based devices from a remote user equipment (UE). The device may also send both a resource range and a starting resource to enable each of the plurality of aircraft-based devices to calculate resources for communicating a discovery signal, as well as a code and / or gap duration. In some implementations, the device may stop assigning a dynamic relay ID to an additional aircraft-based device in response to a threshold number of dynamic relay IDs having been assigned. The device may reassign a dynamic relay ID from a first aircraft-based device that has left an out-of-coverage area to a second aircraft-based device in an out-of-coverage area.

[0137] Example aspects

[0138] Aspect 1: A method for wireless communication by an aircraft-based device, the method comprising: receiving a dynamic relay identification (ID); communicating a discovery signal using resources mapped to the relay ID; and communicating a response signal using the resources mapped to the relay ID.

[0139] Aspect 2: According to the method described in Aspect 1, the method also includes: synchronizing with a remote user equipment (UE) outside the ground cellular coverage based on the discovery signal and the response signal; and after synchronizing with the remote UE, relaying an emergency message from the remote UE to a network device.

[0140] Aspect 3: The method according to aspect 1 or 2, wherein communicating the discovery signal comprises receiving the discovery signal from the remote UE, and the method further comprises synchronizing with the remote UE based on the discovery signal before sending the response signal.

[0141] Aspect 4: A method according to Aspect 1 or 2, wherein communicating the discovery signal includes sending the discovery signal toward a zone covering an outer area, and the method further includes calculating a timing advance based on the position of the aircraft-based device and the zone, and calculating a frequency compensation based on at least one of: the speed and direction of the aircraft-based device; and the position of the aircraft-based device.

[0142] Aspect 5: The method according to any one of the preceding aspects, wherein the discovery signal comprises a first preamble that is the same as a preamble of another aircraft based device.

[0143] Aspect 6: According to the method according to any one of the preceding aspects, the method further includes sending a subsequent preamble code offset by a time domain guard gap and / or a frequency domain guard gap.

[0144] Aspect 7: According to the method according to any one of the preceding aspects, the method further comprises sending a subsequent preamble code overlapping with the first preamble code, the first preamble code and the subsequent preamble code having different orthogonal cover codes.

[0145] Aspect 8: The method according to any one of the preceding aspects further comprises synchronizing to a satellite synchronization signal.

[0146] Aspect 9: The method according to any of the preceding aspects, further comprising receiving a resource range, a starting resource to enable calculation of resources for communicating the discovery signal, and a code and / or a gap duration.

[0147] Aspect 10: A method for wireless communication by a network device, the method comprising: estimating the position of each aircraft-based device in a plurality of aircraft-based devices; and sending a dynamic relay identification (ID) to each aircraft-based device in the plurality of aircraft-based devices based on the corresponding estimated position relative to an out-of-coverage area.

[0148] Aspect 11: The method of aspect 10, further comprising receiving an emergency message from a remote user equipment (UE) relayed via at least one aircraft-based device among the plurality of aircraft-based devices.

[0149] Aspect 12: The method according to aspect 10 or 11, further comprising sending both a resource range and a starting resource to enable each of the plurality of aircraft-based devices to calculate a resource for communicating a discovery signal, and a code and / or a gap duration.

[0150] Aspect 13: The method according to any one of aspects 10 to 12, wherein estimating the position of each of the plurality of aircraft-based devices is based on a predicted trajectory of each of the plurality of aircraft-based devices.

[0151] Aspect 14: The method according to any one of aspects 10 to 13, wherein estimating the position of each of the plurality of aircraft-based devices is based on reported information from each of the plurality of aircraft-based devices.

[0152] Aspect 15: A method according to any one of Aspects 10 to 14, wherein the report information includes at least one of the following: a position of the device based on the aircraft, a reference signal received power (RSRP) of a beam received from the network device, and timer information.

[0153] Aspect 16: The method of any one of aspects 10 to 15, further comprising ceasing to assign dynamic relay IDs to additional aircraft-based devices in response to a threshold number of dynamic relay IDs having been assigned.

[0154] Aspect 17: The method according to any one of aspects 10 to 16, further comprising reassigning a dynamic relay ID from a first aircraft-based device that has left the out-of-coverage area to a second aircraft-based device in the out-of-coverage area.

[0155] Aspect 18: A device for wireless communication, the device comprising: a memory; and at least one processor, the at least one processor being coupled to the memory, the at least one processor being configured to: receive a dynamic relay identification (ID); communicate a discovery signal using resources mapped to the relay ID; and communicate a response signal using the resources mapped to the relay ID.

[0156] Aspect 19: An apparatus according to Aspect 18, wherein the at least one processor is further configured to: synchronize with a remote user equipment (UE) outside of terrestrial cellular coverage based on the discovery signal and the response signal; and after synchronizing with the remote UE, relay an emergency message from the remote UE to a network device.

[0157] Aspect 20: The apparatus according to aspect 18 or 19, wherein the at least one processor communicates the discovery signal by receiving the discovery signal from the remote UE, and is further configured to synchronize with the remote UE based on the discovery signal before sending the response signal.

[0158] Aspect 21: An apparatus according to Aspect 18 or 19, wherein the at least one processor communicates the discovery signal by sending the discovery signal toward a zone covering an outer area, and is further configured to calculate a timing advance based on the position of the aircraft-based device and the zone, and to calculate a frequency compensation based on at least one of: a speed and direction of the aircraft-based device; and the position of the aircraft-based device.

[0159] Aspect 22: The apparatus according to any one of aspects 18 to 21, wherein the discovery signal comprises a first preamble that is the same as a preamble of another aircraft-based device.

[0160] Aspect 23: An apparatus according to any one of aspects 18 to 22, wherein the at least one processor is further configured to send a subsequent preamble offset by a time domain guard gap and / or a frequency domain guard gap.

[0161] Aspect 24: An apparatus according to any one of aspects 18 to 23, wherein the at least one processor is further configured to send a subsequent preamble code overlapping with the first preamble code, the first preamble code and the subsequent preamble code having different orthogonal cover codes.

[0162] Aspect 25: The apparatus according to any one of aspects 18 to 24, wherein the at least one processor is further configured to synchronize to a satellite synchronization signal.

[0163] Aspect 26: The apparatus according to any one of aspects 18 to 25, wherein the at least one processor is further configured to receive a resource range, a starting resource to enable calculation of resources for communicating the discovery signal, and a code and / or a gap duration.

[0164] Aspect 27: An apparatus for wireless communication by a network device, the apparatus comprising: a memory; and at least one processor, the at least one processor coupled to the memory, the at least one processor being configured to: estimate the position of each aircraft-based device in a plurality of aircraft-based devices; and send a dynamic relay identification (ID) to each aircraft-based device in the plurality of aircraft-based devices based on a corresponding estimated position relative to an out-of-coverage area.

[0165] Aspect 28: The apparatus of aspect 27, wherein the at least one processor is further configured to receive an emergency message from a remote user equipment (UE) relayed via at least one aircraft-based device of the plurality of aircraft-based devices.

[0166] Aspect 29: An apparatus according to Aspect 27 or 28, wherein the at least one processor is further configured to send both a resource range and a starting resource to enable each of the multiple aircraft-based devices to calculate the resources used to communicate the discovery signal, as well as the code and / or gap duration.

[0167] Aspect 30: An apparatus according to any one of Aspects 27 to 29, wherein the at least one processor estimates the position of each of the plurality of aircraft-based devices based on a predicted trajectory of each of the plurality of aircraft-based devices.

[0168] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of these aspects.

[0169] As used, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. As used, a processor is implemented using hardware, firmware, and / or a combination of hardware and software.

[0170] Some aspects are described in conjunction with thresholds. As used, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0171] It will be apparent that the described systems and / or methods can be implemented in various forms of hardware, firmware, and / or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit the aspects. Therefore, the operation and performance of these systems and / or methods are described without reference to specific software code, and it should be understood that software and hardware used to implement these systems and / or methods can be designed based at least in part on these descriptions.

[0172] Although the specific combination of features is set forth in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner that is not specifically set forth in the claims and / or is not disclosed in the specification. Although each dependent claim listed below may directly rely only on one claim, the disclosure of various aspects includes each dependent claim combined with each other claim in the claim set. The phrase "at least one" mentioned in the list of items refers to any combination of those items, including a single member. For example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, and any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc, or any other ordering of a, b and c).

[0173] The elements, actions or instructions used should not be interpreted as critical or essential unless explicitly described as such. In addition, as used, the articles "a" and "an" are intended to include one or more items, and they can be used interchangeably with "one or more". In addition, as used, the terms "set" and "group" are intended to include one or more items (e.g., related items, unrelated items, combinations of related items and unrelated items, etc.), and can be used interchangeably with "one or more". If only one item is intended to be referred to, the phrase "only one" or similar terms will be used. In addition, as used, the terms "having" and the like are intended to be open terms. In addition, the phrase "based on" is intended to mean "based at least in part on", unless explicitly stated otherwise.

Claims

1. A method for wireless communication by an aircraft-based device, the method comprising: Receive a dynamic relay identification (ID); communicating a discovery signal using a resource mapped to the relay ID; as well as A response signal is communicated using the resource mapped to the relay ID.

2. The method according to claim 1, further comprising: synchronizing with a remote user equipment (UE) outside of terrestrial cellular coverage based on the discovery signal and the response signal; as well as After synchronization with the remote UE, an emergency message is relayed from the remote UE to a network device. 3 . The method of claim 2 , wherein communicating the discovery signal comprises receiving the discovery signal from the remote UE, the method further comprising synchronizing with the remote UE based on the discovery signal before sending the response signal.

4. The method of claim 1 , wherein communicating the discovery signal comprises sending the discovery signal toward a zone of coverage out of an area, the method further comprising calculating a timing advance based on a location of the aircraft-based device and the zone, and calculating a frequency compensation based on at least one of: a speed and a direction of the aircraft-based device; The location of the aircraft-based device. The method of claim 1 , wherein the discovery signal comprises a first preamble that is identical to a preamble of another aircraft based device.

6. The method according to claim 5, further comprising sending a subsequent preamble code offset by a time domain guard gap and / or a frequency domain guard gap.

7. The method of claim 5, further comprising sending a subsequent preamble overlapping with the first preamble, the first preamble and the subsequent preamble having different orthogonal cover codes.

8. The method of claim 1, further comprising synchronizing to a satellite synchronization signal.

9. The method of claim 1, further comprising receiving a resource range, a starting resource to enable calculation of resources for communicating the discovery signal, and a code and / or a gap duration.

10. A method for wireless communication by a network device, the method comprising: estimating a position of each of the plurality of aircraft-based devices; as well as A dynamic relay identification (ID) is sent to each aircraft-based device of the plurality of aircraft-based devices based on a respective estimated location relative to the out-of-coverage area.

11. The method of claim 10, further comprising receiving an emergency message from a remote user equipment (UE) relayed via at least one aircraft-based device of the plurality of aircraft-based devices.

12. The method of claim 10, further comprising sending both a resource range and a starting resource to enable calculation of resources, and a code and / or gap duration for communicating a discovery signal by each of the plurality of aircraft-based devices. 13 . The method of claim 10 , wherein estimating the position of each of the plurality of aircraft-based devices is based on a predicted trajectory of each of the plurality of aircraft-based devices. 14 . The method of claim 10 , wherein estimating the position of each of the plurality of aircraft-based devices is based on reported information from each of the plurality of aircraft-based devices. 15 . The method of claim 14 , wherein the report information comprises at least one of: a location of the aircraft-based device, a reference signal received power (RSRP) of a beam received from the network device, and timer information. 16 . The method of claim 10 , further comprising ceasing to assign dynamic relay IDs to additional aircraft-based devices in response to a threshold number of dynamic relay IDs having been assigned.

17. The method of claim 10, further comprising reassigning a dynamic relay ID from a first aircraft-based device that has left the out-of-coverage area to a second aircraft-based device in the out-of-coverage area.

18. An apparatus for wireless communication by an aircraft-based device, the apparatus comprising: Memory; and at least one processor, the at least one processor coupled to the memory, the at least one processor configured to: Receive a dynamic relay identification (ID); communicating a discovery signal using a resource mapped to the relay ID; as well as A response signal is communicated using the resource mapped to the relay ID.

19. The apparatus of claim 18, wherein the at least one processor is further configured to: synchronizing with a remote user equipment (UE) outside of terrestrial cellular coverage based on the discovery signal and the response signal; and After synchronization with the remote UE, an emergency message is relayed from the remote UE to a network device.

20. The apparatus of claim 19, wherein the at least one processor communicates the discovery signal by receiving the discovery signal from the remote UE, and is further configured to synchronize with the remote UE based on the discovery signal before sending the response signal.

21. The apparatus of claim 18, wherein the at least one processor communicates the discovery signal by sending the discovery signal toward a zone covering an outer area, and is further configured to calculate a timing advance based on a location of the aircraft-based device and the zone, and to calculate a frequency compensation based on at least one of: a speed and direction of the aircraft-based device; and the location of the aircraft-based device.

22. The apparatus of claim 18, wherein the discovery signal comprises a first preamble that is identical to a preamble of another aircraft based device.

23. The apparatus of claim 22, wherein the at least one processor is further configured to send a subsequent preamble offset by a time domain guard gap and / or a frequency domain guard gap.

24. The apparatus of claim 22, wherein the at least one processor is further configured to transmit a subsequent preamble that overlaps with the first preamble, the first preamble and the subsequent preamble having different orthogonal cover codes.

25. The apparatus of claim 18, wherein the at least one processor is further configured to synchronize to a satellite synchronization signal.

26. The apparatus of claim 18, wherein the at least one processor is further configured to receive a resource range, a starting resource to enable calculation of resources for communicating the discovery signal, and a code and / or a gap duration.

27. An apparatus for wireless communication by a network device, the apparatus comprising: Memory; and at least one processor, the at least one processor coupled to the memory, the at least one processor configured to: estimating a position of each of the plurality of aircraft-based devices; as well as A dynamic relay identification (ID) is sent to each aircraft-based device of the plurality of aircraft-based devices based on a respective estimated location relative to the out-of-coverage area.

28. The apparatus of claim 27, wherein the at least one processor is further configured to receive an emergency message from a remote user equipment (UE) relayed via at least one aircraft-based device of the plurality of aircraft-based devices.

29. The apparatus of claim 27, wherein the at least one processor is further configured to send both a resource range and a starting resource to enable calculation by each of the plurality of aircraft-based devices of resources for communicating a discovery signal, as well as a code and / or a gap duration.

30. The apparatus of claim 27, wherein the at least one processor is configured to estimate the position of each of the plurality of aircraft-based devices based on a predicted trajectory of each of the plurality of aircraft-based devices.

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