WO2021168485A1 - Distribution of location information to aid user equipment link with moving non-terrestrial network nodes - Google Patents

Distribution of location information to aid user equipment link with moving non-terrestrial network nodes Download PDF

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Publication number
WO2021168485A1
WO2021168485A1 PCT/US2021/070176 US2021070176W WO2021168485A1 WO 2021168485 A1 WO2021168485 A1 WO 2021168485A1 US 2021070176 W US2021070176 W US 2021070176W WO 2021168485 A1 WO2021168485 A1 WO 2021168485A1
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WO
WIPO (PCT)
Prior art keywords
location information
indication
hap
sib
node
Prior art date
Application number
PCT/US2021/070176
Other languages
French (fr)
Inventor
Sharath Ananth
Brian Barritt
Pavan Nuggehalli
Nidhi GULIA
Original Assignee
Softbank, Corp.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Softbank, Corp. filed Critical Softbank, Corp.
Publication of WO2021168485A1 publication Critical patent/WO2021168485A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/18502—Airborne stations
    • H04B7/18504—Aircraft used as relay or high altitude atmospheric platform
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
    • H04W48/12—Access restriction or access information delivery, e.g. discovery data delivery using downlink control channel
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • H04W64/003—Locating users or terminals or network equipment for network management purposes, e.g. mobility management locating network equipment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/06—Airborne or Satellite Networks

Definitions

  • Telecommunications connectivity via the Internet, cellular data networks and other systems is available in many parts of the world. Some systems are able to provide network access to remote locations or to locations with limited networking infrastructure via satellites or other high-altitude platforms (HAPs) that are located in the stratosphere. HAPs may communicate with each other and with ground-based networking equipment and mobile devices to provide telecommunications connectivity, for instance according to the Long-Term Evolution (LTE) standard or other types of standards. In order to provide network access to user equipment (UE), HAPs and other moving platforms of the network may need to transmit location information to the UE.
  • LTE Long-Term Evolution
  • UE user equipment
  • HAPs and other moving platforms of the network may need to transmit location information to the UE.
  • HAP nodes such as satellites
  • SIB System Information Block
  • Some HAP nodes such as satellites, may have a predefined or predictable motion.
  • Other HAP nodes such as balloons or drones, may have motion that is not predefined or is variable under different conditions.
  • a way for communicating the location information of a HAP node to UE in these circumstances is needed to allow for the UE to communicate with a HAP node.
  • the UE may use the received location information of the HAP node with the UE’s location to compensate for motion of the HAP node when transmitting information to the HAP node.
  • aspects of the disclosure provide for a method that includes transmitting, by one or more processors of a high-altitude platform (HAP) node, a first indication of location information in a first System Information Block (SIB) to a geographic region; transmitting, by the one or more processors, a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establishing, by the one or more processors, a communication link with the UE according to the first indication of location information and the second indication of location information.
  • HAP high-altitude platform
  • SIB System Information Block
  • the second indication of location information is a greater amount of data than the first indication of location information.
  • the first indication of location information includes an identification of the HAP node as a moving base station.
  • the second indication of location information includes a current location of the HAP node.
  • the current location of the HAP node optionally includes a longitude, a latitude, a height, and a timestamp.
  • the first SIB is transmitted at regular intervals to the geographic region.
  • the second SIB is optionally transmitted at regular intervals to the geographic region.
  • the method optionally includes receiving, from the UE in the geographic region, a request for the second SIB based on the first SIB; wherein the transmitting of the second SIB occurs after the receiving of the request.
  • HAP high-altitude platform
  • the one or more processors are configured to transmit a first indication of location information in a first System Information Block (SIB) to a geographic region; transmit a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establish, using the one or more transceivers, a communication link with the UE according to the first indication of location information and the second indication of location information.
  • SIB System Information Block
  • UE user equipment
  • the second indication of location information is a greater amount of data than the first indication of location information.
  • the first indication of location information includes an identification of the HAP as a moving base station.
  • the second indication of location information includes a current location of the HAP.
  • the current location of the HAP optionally includes a longitude, a latitude, a height, and a timestamp.
  • the first SIB is transmitted at regular intervals to the geographic region.
  • the second SIB is optionally transmitted at regular intervals to the geographic region.
  • the one or more processors are also configured to receive, from the UE in the geographic region, a request for the second SIB based on the first SIB; wherein the one or more processors are configured to transmit the second SIB after the receiving of the request [0010]
  • a non -transitory, computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors of a high-altitude platform (HAP) node to perform a method.
  • HAP high-altitude platform
  • the method comprising transmitting a first indication of location information in a first System Information Block (SIB) to a geographic region; transmitting a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establishing a communication link with the UE according to the first indication of location information and the second indication of location information.
  • SIB System Information Block
  • UE user equipment
  • the second indication of location information is a greater amount of data than the first indication of location information.
  • the first indication of location information includes an identification of the HAP node as a moving base station, and the second indication of location information includes a current location of the HAP node.
  • the first SIB is transmitted at regular intervals to the geographic region.
  • FIGURE 1 is a pictorial diagram of a portion of an example network in accordance with aspects of the disclosure.
  • FIGURE 2 is a diagram of an example network in accordance with aspects of the disclosure.
  • FIGURE 3 is a functional diagram of the portion of the network shown in FIGURE 1 in accordance with aspects of the disclosure.
  • FIGURE 4 is an example of a balloon platform with lateral propulsion in accordance with aspects of the technology.
  • FIGURE 5 shows a flow diagram of a method in accordance with aspects of the technology.
  • FIGURE 1 is a pictorial diagram of an example system 100 of network nodes in a network.
  • the network may include nodes mounted on various land- and air-based devices, some of which may change position with respect to other nodes in the network over time.
  • the network includes, as nodes, a first terrestrial tower 110 and a second terrestrial tower 112.
  • the network also includes as a node a high-altitude platform 114.
  • HAP 114 is a balloon.
  • the HAP may be a blimp, an airplane, an unmanned aerial vehicle (UAV) such as a drone, a satellite, or another platform capable of low Earth orbit.
  • UAV unmanned aerial vehicle
  • Nodes in the network may be equipped to transmit and receive mmWave signals or other very high frequency signals. Additionally or alternatively, nodes in the network may be equipped to transmit and receive other radio-frequency signals, optical signals, or other communication signal capable of travelling through free space.
  • the network may be a hybrid network. Arrows shown projecting from nodes represent possible paths 120, 122a, 122b, 124, 126, 128, 130 for a transmitted communication signal. As shown in FIGURE 1, some possible paths may be blocked by buildings, such as buildings 140, 142. For example, a signal following path 120 from node 110 may be angled below the horizon and be blocked by building 140.
  • a signal following path 122a from node 110 may be angled above path 120, avoiding building 140, but then may contact building 142.
  • the signal following path 122a may reflect off building 142 and follow path 122b towards the ground location of a user 150, carrying a UE 152.
  • a signal following path 124 from node 110 may be angled towards or above the horizon, nearly parallel to the ground, passing over building 140, but then may be blocked by building 142.
  • a signal following path 126 from node 110 may be angled above the horizon and reach node 114.
  • a signal following path 128 from node 114 directed to the ground location of user 150.
  • a signal following path 130 from node 114 may be angled below the horizon, pass over building 142, and reach node 112.
  • a signal may be transmitted from the UE 152 of the user 150 back towards one or more nodes of the network.
  • a signal from the UE 152 may be transmitted back along paths 122b and 122a towards node 110.
  • Another signal from the UE 152 may be transmitted back along path 128 towards node 114.
  • multiple users or multiple UE may form bi directional access links with a given node of the network at a given point in time, in addition to the user 150 and the UE 152 shown in FIGURE 1.
  • the network nodes as shown in FIGURE 1 is illustrative only, and the network may include additional or different nodes.
  • the network may include additional HAPs and/or additional terrestrial towers.
  • the network may also include a plurality of additional devices, such as various devices supporting a telecommunication service or other systems that may participate in the network.
  • the network may be defined as a hybrid HAP/satellite network.
  • the network 200 that includes the system 100 may also include as nodes additional terrestrial towers 210, 220, 230, and 240. Arrows shown between a pair of nodes represent possible communication paths between the nodes. In addition to paths 124, 126, and 130 corresponding to the paths shown in FIGURE 1, paths 250-257 are shown between the nodes.
  • the network 200 as shown in FIGURE 2 is illustrative only, and in some implementations the network 200 may include additional or different nodes.
  • the status information received from the nodes of the network may include the location information of HAP 114 or weather conditions at locations of terrestrial towers 110, 112, 210, 220, 230, and 240 at a current time or a future time.
  • the location information of HAP 114 may include a projected trajectory or set location, such as a future location at the future time that is in signal range of the terrestrial towers 110, 112.
  • the network may serve as an access network for UE such as cellular phones, laptop computers, desktop computers, wearable devices, or tablet computers. Other devices may be able to access the network as part of the Internet of things.
  • nodes 110, 112, 114 may connect to the datacenters via wireless, fiber, or cable backbone network links or transit networks operated by third parties.
  • the nodes 110, 112, 114 may provide wireless access for the users, and may forward user requests to the datacenters and return responses to the users via the backbone network links.
  • the first terrestrial tower 110, the second terrestrial tower 112, and the HAP 114 may include wireless transceivers configured to operate in a cellular or other mobile network, such as 5G NR (new radio) networks or LTE networks.
  • the nodes 110, 112, 114 may operate as gNodeB stations, eNodeB stations, or other wireless access points, such as IEEE 802.11 (including any of the IEEE 802.11 revisions), WiMAX, or UMTS access points.
  • One or more terrestrial towers in the network may include an optical fiber or other link connecting the one or more terrestrial towers to another terrestrial tower or datacenter.
  • the second terrestrial tower 112 may include fiber 113, shown by a dotted arrow, that connects to another terrestrial tower (not shown).
  • user 150 carrying a UE 152 may be configured to communicate with one or more of the nodes in the network.
  • the communication between a node of the network such as one between HAP node 114 and the UE 152, may include transmission of access information, such as in one or more System Information Blocks (SIBs).
  • SIBs System Information Blocks
  • the transmission of SIBs may be governed by a network standard.
  • the network also may be connected to a larger network, such as the Internet, and may be configured to provide a UE with access to resources stored on or provided through the larger computer network.
  • each node such as first terrestrial tower 110, second terrestrial tower 112, and HAP 114, may include one or more transceivers configured to transmit and receive communication signals and create one or more communication links with another node in the network.
  • each of the nodes may include one or more processors 310, memory 312, one or more transceivers 320, and one or more antenna 322. While only terrestrial towers 110, 112 and HAP 114 are shown, other terrestrial towers and HAPs in the network may have the same or as similar configurations.
  • the one or more processors 310 may be any conventional processors, such as commercially available CPUs. Alternatively, the one or more processors may be a dedicated device such as an application specific integrated circuit (ASIC) or other hardware -based processor, such as a field programmable gate array (FPGA). The one or more processors 310 may be configured to operate according to a given protocol architecture for a mobile network, such as 5G NR architecture or LTE radio protocol architecture.
  • FIGURE 3 functionally illustrates the one or more processors 310 and memory 312 as being within the same block, it will be understood that the one or more processors 310 and memory 312 may actually comprise multiple processors and memories that may or may not be stored within the same physical housing. Accordingly, references to a processor or computer will be understood to include references to a collection of processors or computers or memories that may or may not operate in parallel.
  • Memory 312 stores information accessible by the one or more processors 310, including data 314, and instructions 316, that may be executed by the one or more processors 310.
  • the memory may be of any type capable of storing information accessible by the processor, including non -transitory and tangible computer-readable mediums containing computer readable instructions such as a hard-drive, memory card, ROM, RAM, DVD or other optical disks, as well as other write-capable and read-only memories.
  • the system and method may include different combinations of the foregoing, whereby different portions of the data 314 and instructions 316 are stored on different types of media.
  • a forwarding information base or forwarding table may be stored that indicate how signals received at each node should be forwarded, or transmitted.
  • the forwarding table stored in memory 312 may indicate that a signal received from terrestrial tower 110 should be forwarded to terrestrial tower 112.
  • Data 314 may be retrieved, stored or modified by the one or more processors 310 in accordance with the instructions 316.
  • the data 314 may be stored in computer registers, in a relational database as a table having a plurality of different fields and records, XML documents or flat files.
  • the data 314 may also be formatted in any computer-readable format such as, but not limited to, binary values or Unicode.
  • image data may be stored as bitmaps comprised of grids of pixels that are stored in accordance with formats that are compressed or uncompressed, lossless (e.g., BMP) or lossy (e.g., JPEG), and bitmap or vector-based (e.g., SVG), as well as computer instructions for drawing graphics.
  • the data 314 may comprise any information sufficient to identify the relevant information, such as numbers, descriptive text, proprietary codes, references to data stored in other areas of the same memory or different memories (including other network locations) or information that is used by a function to calculate the relevant data.
  • the instructions 316 may be any set of instructions to be executed directly (such as machine code) or indirectly (such as scripts) by the one or more processors 310.
  • the instructions 316 may include the given protocol architecture for the mobile network of which the node is a part.
  • the given protocol architecture may include a split architecture between a central unit and a distributed unit.
  • the given protocol architecture may define a control plane, a user plane, or other protocol layers.
  • the given protocol architecture may also include an interface that defines a plurality of messages for use in communication between the protocol layers.
  • the instructions 316 may be stored as computer code on the computer-readable medium. In that regard, the terms "instructions" and “programs” may be used interchangeably herein.
  • the instructions 316 may be stored in object code format for direct processing by the one or more processors 310, or in any other computer language including scripts or collections of independent source code modules that are interpreted on demand or compiled in advance. Functions, methods and routines of the instructions 316 are explained in more detail below.
  • the one or more transceivers 320 may include at least one wireless transceiver.
  • the at least one wireless transceiver may include one or more high-power light-emitting diodes (LEDs) or a laser systems configured to transmit an optical signal for free-space optical communications. Other types of free-space communication are possible.
  • the at least one wireless transceiver may include one or more optical receivers.
  • the one or more transceivers 320 may also include at least one transceiver configured to communicate via a fiber or cable connection.
  • the one or more antennas 322 may each provide coverage for one or more sectors with different beams.
  • a steering mechanism such as a gimbal, may be configured to point an antenna of one or more antennas 322 in a pointing direction.
  • the wireless transceivers and/or the antennas of the respective nodes can be controlled to point in the direction of one another so that data can be sent and received between the nodes.
  • the UE 152 associated with user 150 may be a personal computing device or a server with one or more processors 350, memory 352, data 354, and instructions 356 similar to those described above with respect to the one or more processors 310, memory 312, data 314, and instructions 316.
  • Personal computing devices may include a personal computer that has all of the components normally used in connection with a personal computer such as a central processing unit (CPU), memory (e.g.
  • UE 152 may be any device capable of processing instructions and transmitting data to and from humans and other computers including general purpose computers, network computers lacking local storage capability, and set-top boxes for televisions.
  • UE may be associated with one or more self-defined network (SDN) applications and may have one or more northbound interface (NBI) drivers.
  • SDN self-defined network
  • NBI northbound interface
  • the network topology may change as one or more HAP nodes move relative to other nodes and/or relative to the ground. Accordingly, the network may apply a mesh protocol to update the state of the network as the topology of the network changes.
  • the network may also implement station keeping functions using winds and altitude control or lateral propulsion to help provide a desired network topology. For example, station-keeping may involve some or all of HAP nodes of the network maintaining and/or moving into a certain position relative to one or more other balloons in the network (and possibly in a certain position relative to a terrestrial node or service area).
  • each HAP node may implement station-keeping functions to determine its desired positioning within the desired topology, and if necessary, to determine how to move to and/or maintain the desired position. For instance, the HAP nodes may move in response to riding a wind current, or may move in a circular or other pattern as they station keep over a region of interest.
  • the desired topology may vary depending upon the particular implementation and whether or not the HAP nodes are continuously moving.
  • HAP nodes may implement station keeping to provide a substantially uniform topology where the HAP nodes function to position themselves at substantially the same distance (or within a certain range of distances) from adjacent nodes in the network.
  • the network may have a non-uniform topology where HAP nodes are distributed more or less densely in certain areas, for various reasons.
  • HAP nodes may be clustered more densely over areas with greater demand (such as urban areas) and less densely over areas with lesser demand (such as over large bodies of water).
  • the topology of an example network may be adaptable allowing HAP nodes to adjust their respective positioning in accordance with a change in the desired topology of the network.
  • the network can be an SDN that is controlled by an SDN controller.
  • the network controller may be located at one of the network nodes or at a separate platform, such as, for example, in a datacenter.
  • the nodes of the network, including nodes 110, 112, 114 may be configured to communicate with one another using the steerable transceivers, such as the one or more transceivers 320.
  • HAPs in the network such as HAP 114
  • other nodes in the network such as terrestrial towers 110, 112
  • some network links may become infeasible due to range of the transceivers or obstacles between the nodes.
  • the configuration of the network may require regular (i.e., periodic) or irregular reconfiguration using the network controller to maintain connectivity and to satisfy determined network flows.
  • the HAP 114 of FIGURE 1 may be a high -altitude balloon or other type of HAPs that are deployed in the stratosphere.
  • the HAP nodes in the network may generally be configured to operate at stratospheric altitudes, e.g., between 50,000 ft and 70,000 ft or more or less, in order to limit the HAPs' exposure to high winds and interference with commercial airplane flights.
  • the HAPs may be configured to move latitudinally and/or longitudinally relative to one another by adjusting their respective altitudes, such that the wind carries the respective balloons to the respectively desired locations. Lateral propulsion may also be employed to affect the balloon’s path of travel.
  • FIGURE 4 illustrates one example configuration 400 of a balloon platform with propeller- based lateral propulsion, which may represent HAP 114 of FIGURE 1.
  • the example 400 includes an envelope 402, a payload 404 and a down connect member 406 disposed between the envelope 402 and the payload 404.
  • At least one gore panel forms the envelope, which is configured to maintain pressurized lifting gas therein.
  • the balloon may be a superpressure balloon.
  • a top plate may be disposed along an upper section of the envelope, while a base plate may be disposed along a lower section of the envelope opposite the top place.
  • the coupling member 406 may connect the payload 404 with the base plate.
  • the envelope 402 may take various shapes and forms.
  • the envelope 402 may be made of materials such as polyethylene, mylar, FEP, rubber, latex or other thin film materials or composite laminates of those materials with fiber reinforcements imbedded inside or outside. Other materials or combinations thereof or laminations may also be employed to deliver required strength, gas barrier, RF and thermal properties.
  • the shape and size of the envelope 402 may vary depending upon the particular implementation.
  • the envelope 402 may be filled with different types of gases, such as air, helium and/or hydrogen. Other types of gases, and combinations thereof, are possible as well.
  • Shapes may include typical balloon shapes like spheres and “pumpkins”, or aerodynamic shapes that are symmetric, provide shaped lift, or are changeable in shape. Lift may come from lift gasses (e.g., helium, hydrogen), electrostatic charging of conductive surfaces, aerodynamic lift (wing shapes), air moving devices (propellers, flapping wings, electrostatic propulsion, etc.) or any hybrid combination of lifting techniques.
  • the payload 404 may include the one or more processors 310, the memory 312, the one or more transceivers 320, and the one or more antennas 322 of HAP 114.
  • the payload 404 may additionally include a positioning system.
  • the positioning system could include, for example, a global positioning system (GPS), an inertial navigation system, and/or a star-tracking system.
  • the positioning system may additionally or alternatively include various motion sensors (e.g., accelerometers, magnetometers, gyroscopes, and/or compasses).
  • a navigation system may additionally be included in the payload.
  • the navigation system may implement station-keeping functions to maintain position within and/or move to a position in accordance with a desired topology or other service requirement.
  • the navigation system may use wind data (e.g., from onboard and/or remote sensors) to determine altitudinal and/or lateral positional adjustments that result in the wind carrying the balloon in a desired direction and/or to a desired location.
  • Lateral positional adjustments may also be handled directly by a lateral positioning system that is separate from the payload.
  • the altitudinal and/or lateral adjustments may be computed by a central control location and transmitted by a ground based, air based, or satellite based system and communicated to the high-altitude balloon.
  • specific balloons may be configured to compute altitudinal and/or lateral adjustments for other balloons and transmit the adjustment commands to those other balloons.
  • the navigation system is able to evaluate data obtained from onboard navigation sensors, such as an inertial measurement unit (IMU) and/or differential GPS, received data (e.g., weather information), and/or other sensors such as health and performance sensors (e.g., a force torque sensor) to manage operation of the balloon’s systems.
  • IMU inertial measurement unit
  • differential GPS e.g., GPS
  • received data e.g., weather information
  • health and performance sensors e.g., a force torque sensor
  • the navigation system When decisions are made to activate the lateral propulsion system, for instance to station keep, the navigation system then leverages received sensor data for position, wind direction, altitude and power availability to properly point the propeller and to provide a specific thrust condition for a specific duration or until a specific condition is reached (e.g., a specific velocity or position is reached, while monitoring and reporting overall system health, temperature, vibration, and other performance parameters).
  • a specific condition e.g., a specific velocity or position is reached, while monitoring and reporting overall system health, temperature, vibration, and other performance parameters.
  • Cables or other wiring between the payload 404 and the envelope 402 may be run within the down connect member 406.
  • One or more solar panel assemblies 408 may be coupled to the payload 404 or another part of the balloon platform.
  • the payload 404 and the solar panel assemblies 408 may be configured to rotate about the down connect member 406 (e.g., up to 360° rotation), for instance to align the solar panel assemblies 408 with the sun to maximize power generation.
  • Example 400 also illustrates an example lateral propulsion system 410. While this example of the lateral propulsion system 410 is one possibility, the location could also be fore and/or aft of the payload section 404, or fore and/or aft of the envelope section 402, or any other location that provides the desired thrust vector.
  • HAP nodes of the network may include drones flying routes in an autonomous manner, carrying cameras for aerial photography, and transporting goods from one place to another.
  • UAV unmanned aerial vehicle
  • flying robot are often used as synonyms for a drone.
  • the spectrum of applications is broad, including aerial monitoring of industrial plants and agriculture fields as well as support for first time responders in case of disasters. For some applications, it is beneficial if a team of drones rather than a single drone is employed. Multiple drones can cover a given area faster or take photos from different perspectives at the same time.
  • a first System Information Block may be defined to carry information that is critical to initiating communication with a node of the network (e.g., access information related to a Random Access Channel (RACH)).
  • SIB1 may be transmitted periodically by one or more processors of a HAP node, such as one or more processors 310 of HAP node 114, to a geographic region using a fixed schedule.
  • the fixed schedule may be a repeated interval, such as every 80 milliseconds or more or less, or other time frame that is defined by the network standard.
  • a first indication of location information may be included in SIB1 to alert a UE in the geographic region, such as UE 152 that additional location information is needed in order to form a connection with the HAP node.
  • the first indication of location information may be added in an optional field of SIB 1 and include an identification of the HAP node as a moving base station.
  • the first indication of location information may also specify in which SIB the additional location information is. Given the amount of other information included in SIB1, the amount of total location information of the HAP node, and size constraints of SIB 1 , the amount of location information included in SIB 1 may be kept to a minimum. For example, the size of this first indication may be one bit.
  • the additional location information may be included in another SIB different from SIB1, or SIB#, that is transmitted from the HAP node to the UE.
  • the size of the additional information may be greater than the first indication of location information.
  • the additional location information may include a current location of the HAP node at a current time.
  • the current location may be a latitude, longitude, and altitude of the HAP node.
  • the additional location information may additionally or alternatively include an identification for the additional location information, a timestamp, an identification for the HAP node, an address for the HAP node, a trajectory or a predicted motion of the HAP node, a speed of the HAP node, a wind direction at a given altitude, and/or a wind speed at a given altitude .
  • the additional location information may include the entire regular fixed pattern.
  • the additional location information may include an expiration time that indicates when at least one of the additional location information is no longer valid. The expiration information may allow a UE to determine when updated additional location information is needed. Any SIB# received prior to the expiration time may not be process (or read) by the UE since the additional location information prior to the expiration time is still valid.
  • the additional location information may be updated in the memory of the UE with location information based on a new current location of the HAP node at a new current time.
  • the updated additional location information may be assigned a new identification so a UE can quickly identify whether the additional location information has changed from previously received additional location information.
  • the identification of the additional location information is the same as for previously received additional location information, the UE need not further process the additional location information.
  • the updated additional location information may be stored at the memory of the HAP node and then transmitted to the UE.
  • the updates to the additional location information may occur at predefined regular intervals or at points in time defined by a motion of the HAP node, such as a speed at which the HAP node travels.
  • the SIB# may include the following: name: two_line_element type: scalar compound field subfield: line_l (ASCII string with max length of 70 characters) subfield: line_2 (ASCII string with max length of 70 characters)
  • a two-line element set is a data format encoding a list of orbital elements of an Earth-orbiting object for a given point in time.
  • the TLE element set included in the SIB# for a satellite may encode the orbiting pattern of the satellite, from which a UE is able to derive the position of the satellite at a given point in time.
  • the SIB# may include the following: name: timestamped_coordinates type: array of compound fields [max length of 4] subfield[0]: longitude_deg (double precision) subfield[0]: latitude_deg (double precision) subfield[0]: height m (double precision) subfield[0]: speed_mps subfield[0]: timestamp (uint64) subfield[0]: timestamp validity (uint64)
  • Cartographic coordinates that define a position of the HAP node at a given point in time are included in the SIB#.
  • the cartographic coordinates may be relative to the WGS84 reference ellipsoid of the Earth’s surface.
  • longitude and latitude may be in degrees and height may be the distance, in meters, above the WGS84 ellipsoid surface.
  • Speed in this example may be in meters per second.
  • Timestamp is the given point in time at which the cartographic coordinates are valid.
  • the timestamp may be a count of microseconds since the Unix epoch based and may presume that leapseconds are smeared.
  • a timestamp validity defines a period of time from the timestamp after which the timestamped coordinates are too old (i.e., expire).
  • This example SIB# may also be applied to network nodes that are high speed rail platforms or terrestrial platforms.
  • the SIB# is also transmitted periodically by the one or more processors of the HAP node using a fixed schedule.
  • the periodicity of the SIB# may be based on a type of HAP node, such as based on the speed of the HAP node’s motion. For example, the periodicity of a SIB# for a first HAP node may be smaller (i.e., more frequent) than that of a SIB# for a second HAP node when the first HAP node moves faster than the second HAP node.
  • the SIB# is transmitted in response to a request from the UE.
  • This implementation may be utilized when the UE has previous location information for the HAP node such that the UE has an estimated location of the HAP node based on the previous location information to which to send the request.
  • the request may be sent from the UE to the HAP node after the UE receives the first indication in SIB 1.
  • the request may be included in an uplink signal, such as Physical Random Access Channel (PRACH) signal.
  • PRACH Physical Random Access Channel
  • the UE may establish a communication link with the HAP node and/or maintain the communication link with the HAP node by compensating for the HAP node using the location information.
  • the communication link may serve as an access link for the UE to the HAP node and the larger access network.
  • SIB 1 and SIB# is received at UE 152 from HAP node 114
  • communication link may be formed between UE 152 and HAP node 114, , such as along path 128.
  • the UE 152 may use the communication link to access HAP node 114 and network 200.
  • the UE may determine that at least one of the additional location information has expired. The period of time may be determined based on the expiration time in the additional location information.
  • the UE may reread the SIB# in the memory of the UE, which is may now be the updated SIB# including the updated additional information received from a transmission or broadcast from the HAP node.
  • the UE may request an updated SIB# for the HAP node.
  • the HAP node may send another SIB# with updated additional location information.
  • SIBs short term evolution
  • SIB 1 may not include a first indication of location information.
  • the UE may always check for SIB# and the existence of a second indication of location information. If SIB# is not found, then the UE may assume that it is not connecting to a HAP node and proceed with forming a communication link accordingly. If SIB# is found, then the UE uses the additional location information to form a communication link with the HAP node.
  • the UE may be configured with HAP- specific geographical information (such as Global Positioning System coordinates, list of tracking area identities, etc.).
  • the UE may then check for SIB# only when it determines that its location is in a geographic area specified by the HAP-specific configuration.
  • the HAP-specific configuration can be pre-provisioned in the UE, or provisioned and updated by Radio Resource Control (RRC) and/or Non- Access Stratum (NAS) procedures.
  • RRC Radio Resource Control
  • NAS Non- Access Stratum
  • the UE check for the SIB# after receiving a third indication that the HAP node is likely available in a particular location from another node of the network, a network controller, or a central server.
  • a terrestrial node in communication with the HAP node may broadcast at least some location information associated with the HAP node in the third indication such that the UE may be able to initiate a communication with the HAP node.
  • the third indication may also include a physical cell identifier (PCI) of the HAP node.
  • PCI physical cell identifier
  • the technology described herein allows for an efficient means to communicate where a moving HAP node is to a UE so the UE is able to locate and stay connected with the moving HAP node for communication purposes.
  • the technology utilizes System Information Blocks that are already used in LTE or 5G NR systems and customizes a few SIBs to effectively communicate that (1) the HAP node is in motion and (2) the location information of the HAP node. While useful for HAP nodes, this technology is also useful for other types of moving or non-moving nodes.
  • FIGURE 5 shows a flow diagram 500 of a method in accordance with aspects of the technology.
  • one or more processors 310 of HAP node 114 may transmit a first indication of location information in a first SIB to a geographic region.
  • the geographic region may include a UE 152.
  • the UE 152 may receive the first SIB with the first indication of location information and await additional location information.
  • the one or more processors 310 may transmit a second indication of location information in a second SIB to the UE in the geographic region.
  • the UE may receive the second SIB with the second indication of location information, which includes the additional location information.
  • the one or more processors 310 may establish a communication link with the UE 152 according to the first indication of location information and the second indication of location information.
  • the communication link may allow UE 152 to access a network through HAP node 114, such as network 200.

Abstract

A method for establishing a communication link between a high-altitude platform (HAP) node (114) and a user equipment (UE) (152) includes transmitting (502), by one or more processors (310) of the HAP node (114), a first indication of location information in a first System Information Block (SIB) to a geographic region and transmitting (504), by the one or more processors (310), a second indication of location information in a second SIB to the UE in the geographic region. The communication link between the HAP node and the UE may be established (506) by the one or more processors (310) according to the first indication of location information and the second indication of location information.

Description

DISTRIBUTION OF LOCATION INFORMATION TO AID USER EQUIPMENT LINK WITH MOVING NON-TERRESTRIAL NETWORK NODES
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional Application No. 62/979,498, which was filed February 21, 2020.
BACKGROUND
[0002] Telecommunications connectivity via the Internet, cellular data networks and other systems is available in many parts of the world. Some systems are able to provide network access to remote locations or to locations with limited networking infrastructure via satellites or other high-altitude platforms (HAPs) that are located in the stratosphere. HAPs may communicate with each other and with ground-based networking equipment and mobile devices to provide telecommunications connectivity, for instance according to the Long-Term Evolution (LTE) standard or other types of standards. In order to provide network access to user equipment (UE), HAPs and other moving platforms of the network may need to transmit location information to the UE.
BRIEF SUMMARY
[0003] The technology discussed herein is related to distribution of location information of a high- altitude platform (HAP) node to a user equipment (UE) using a System Information Block (SIB). Some HAP nodes, such as satellites, may have a predefined or predictable motion. Other HAP nodes, such as balloons or drones, may have motion that is not predefined or is variable under different conditions. A way for communicating the location information of a HAP node to UE in these circumstances is needed to allow for the UE to communicate with a HAP node. The UE may use the received location information of the HAP node with the UE’s location to compensate for motion of the HAP node when transmitting information to the HAP node.
[0004] Aspects of the disclosure provide for a method that includes transmitting, by one or more processors of a high-altitude platform (HAP) node, a first indication of location information in a first System Information Block (SIB) to a geographic region; transmitting, by the one or more processors, a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establishing, by the one or more processors, a communication link with the UE according to the first indication of location information and the second indication of location information.
[0005] In one example, the second indication of location information is a greater amount of data than the first indication of location information. In another example, the first indication of location information includes an identification of the HAP node as a moving base station. In a further example, the second indication of location information includes a current location of the HAP node. In this example, the current location of the HAP node optionally includes a longitude, a latitude, a height, and a timestamp.
[0006] In yet another example, the first SIB is transmitted at regular intervals to the geographic region. In this example, the second SIB is optionally transmitted at regular intervals to the geographic region. Also in this example, the method optionally includes receiving, from the UE in the geographic region, a request for the second SIB based on the first SIB; wherein the transmitting of the second SIB occurs after the receiving of the request.
[0007] Other aspects of the disclosure provide for a system of a high-altitude platform (HAP) that includes one or more transceivers and one or more processors. The one or more processors are configured to transmit a first indication of location information in a first System Information Block (SIB) to a geographic region; transmit a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establish, using the one or more transceivers, a communication link with the UE according to the first indication of location information and the second indication of location information.
[0008] In one example, the second indication of location information is a greater amount of data than the first indication of location information. In another example, the first indication of location information includes an identification of the HAP as a moving base station. In a further example, the second indication of location information includes a current location of the HAP. In this example, the current location of the HAP optionally includes a longitude, a latitude, a height, and a timestamp. [0009] In yet another example, the first SIB is transmitted at regular intervals to the geographic region. In this example, the second SIB is optionally transmitted at regular intervals to the geographic region. Also in this example, the one or more processors are also configured to receive, from the UE in the geographic region, a request for the second SIB based on the first SIB; wherein the one or more processors are configured to transmit the second SIB after the receiving of the request [0010] Further aspects of the disclosure provide for a non -transitory, computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors of a high-altitude platform (HAP) node to perform a method. The method comprising transmitting a first indication of location information in a first System Information Block (SIB) to a geographic region; transmitting a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establishing a communication link with the UE according to the first indication of location information and the second indication of location information.
[0011] In one example, the second indication of location information is a greater amount of data than the first indication of location information. In another example, the first indication of location information includes an identification of the HAP node as a moving base station, and the second indication of location information includes a current location of the HAP node. In a further example, the first SIB is transmitted at regular intervals to the geographic region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGURE 1 is a pictorial diagram of a portion of an example network in accordance with aspects of the disclosure.
[0013] FIGURE 2 is a diagram of an example network in accordance with aspects of the disclosure. [0014] FIGURE 3 is a functional diagram of the portion of the network shown in FIGURE 1 in accordance with aspects of the disclosure.
[0015] FIGURE 4 is an example of a balloon platform with lateral propulsion in accordance with aspects of the technology.
[0016] FIGURE 5 shows a flow diagram of a method in accordance with aspects of the technology.
DETAILED DESCRIPTION EXAMPLE NETWORKS
[0017] FIGURE 1 is a pictorial diagram of an example system 100 of network nodes in a network. The network may include nodes mounted on various land- and air-based devices, some of which may change position with respect to other nodes in the network over time. For example, as shown in FIGURE 1, the network includes, as nodes, a first terrestrial tower 110 and a second terrestrial tower 112. The network also includes as a node a high-altitude platform 114. As shown, HAP 114 is a balloon. In other embodiments, the HAP may be a blimp, an airplane, an unmanned aerial vehicle (UAV) such as a drone, a satellite, or another platform capable of low Earth orbit.
[0018] Nodes in the network may be equipped to transmit and receive mmWave signals or other very high frequency signals. Additionally or alternatively, nodes in the network may be equipped to transmit and receive other radio-frequency signals, optical signals, or other communication signal capable of travelling through free space. When the nodes in the network implement a combination of different signals for the links of the network, the network may be a hybrid network. Arrows shown projecting from nodes represent possible paths 120, 122a, 122b, 124, 126, 128, 130 for a transmitted communication signal. As shown in FIGURE 1, some possible paths may be blocked by buildings, such as buildings 140, 142. For example, a signal following path 120 from node 110 may be angled below the horizon and be blocked by building 140. A signal following path 122a from node 110 may be angled above path 120, avoiding building 140, but then may contact building 142. The signal following path 122a may reflect off building 142 and follow path 122b towards the ground location of a user 150, carrying a UE 152. A signal following path 124 from node 110 may be angled towards or above the horizon, nearly parallel to the ground, passing over building 140, but then may be blocked by building 142. A signal following path 126 from node 110 may be angled above the horizon and reach node 114. A signal following path 128 from node 114 directed to the ground location of user 150. A signal following path 130 from node 114 may be angled below the horizon, pass over building 142, and reach node 112.
[0019] Also shown in FIGURE 1, a signal may be transmitted from the UE 152 of the user 150 back towards one or more nodes of the network. For example, a signal from the UE 152 may be transmitted back along paths 122b and 122a towards node 110. Another signal from the UE 152 may be transmitted back along path 128 towards node 114. In addition, multiple users or multiple UE may form bi directional access links with a given node of the network at a given point in time, in addition to the user 150 and the UE 152 shown in FIGURE 1.
[0020] The network nodes as shown in FIGURE 1 is illustrative only, and the network may include additional or different nodes. For example, in some implementations, the network may include additional HAPs and/or additional terrestrial towers. The network may also include a plurality of additional devices, such as various devices supporting a telecommunication service or other systems that may participate in the network. When the network includes at least one low Earth orbit or high Earth orbit satellite as well as one other type of HAP, the network may be defined as a hybrid HAP/satellite network.
[0021] For example, as shown in FIGURE 2, the network 200 that includes the system 100 may also include as nodes additional terrestrial towers 210, 220, 230, and 240. Arrows shown between a pair of nodes represent possible communication paths between the nodes. In addition to paths 124, 126, and 130 corresponding to the paths shown in FIGURE 1, paths 250-257 are shown between the nodes. The network 200 as shown in FIGURE 2 is illustrative only, and in some implementations the network 200 may include additional or different nodes. The status information received from the nodes of the network may include the location information of HAP 114 or weather conditions at locations of terrestrial towers 110, 112, 210, 220, 230, and 240 at a current time or a future time. The location information of HAP 114 may include a projected trajectory or set location, such as a future location at the future time that is in signal range of the terrestrial towers 110, 112.
[0022] In some implementations, the network may serve as an access network for UE such as cellular phones, laptop computers, desktop computers, wearable devices, or tablet computers. Other devices may be able to access the network as part of the Internet of things. For example, nodes 110, 112, 114 may connect to the datacenters via wireless, fiber, or cable backbone network links or transit networks operated by third parties. The nodes 110, 112, 114 may provide wireless access for the users, and may forward user requests to the datacenters and return responses to the users via the backbone network links. [0023] In particular, the first terrestrial tower 110, the second terrestrial tower 112, and the HAP 114 may include wireless transceivers configured to operate in a cellular or other mobile network, such as 5G NR (new radio) networks or LTE networks. The nodes 110, 112, 114 may operate as gNodeB stations, eNodeB stations, or other wireless access points, such as IEEE 802.11 (including any of the IEEE 802.11 revisions), WiMAX, or UMTS access points. One or more terrestrial towers in the network may include an optical fiber or other link connecting the one or more terrestrial towers to another terrestrial tower or datacenter. For example, the second terrestrial tower 112 may include fiber 113, shown by a dotted arrow, that connects to another terrestrial tower (not shown). As shown in FIGURE 1, user 150 carrying a UE 152 may be configured to communicate with one or more of the nodes in the network. The communication between a node of the network, such as one between HAP node 114 and the UE 152, may include transmission of access information, such as in one or more System Information Blocks (SIBs). The transmission of SIBs may be governed by a network standard. The network also may be connected to a larger network, such as the Internet, and may be configured to provide a UE with access to resources stored on or provided through the larger computer network. [0024] As shown in FIGURE 3, each node, such as first terrestrial tower 110, second terrestrial tower 112, and HAP 114, may include one or more transceivers configured to transmit and receive communication signals and create one or more communication links with another node in the network. Referring to HAP 114 as an example, each of the nodes, may include one or more processors 310, memory 312, one or more transceivers 320, and one or more antenna 322. While only terrestrial towers 110, 112 and HAP 114 are shown, other terrestrial towers and HAPs in the network may have the same or as similar configurations.
[0025] The one or more processors 310 may be any conventional processors, such as commercially available CPUs. Alternatively, the one or more processors may be a dedicated device such as an application specific integrated circuit (ASIC) or other hardware -based processor, such as a field programmable gate array (FPGA). The one or more processors 310 may be configured to operate according to a given protocol architecture for a mobile network, such as 5G NR architecture or LTE radio protocol architecture. Although FIGURE 3 functionally illustrates the one or more processors 310 and memory 312 as being within the same block, it will be understood that the one or more processors 310 and memory 312 may actually comprise multiple processors and memories that may or may not be stored within the same physical housing. Accordingly, references to a processor or computer will be understood to include references to a collection of processors or computers or memories that may or may not operate in parallel.
[0026] Memory 312 stores information accessible by the one or more processors 310, including data 314, and instructions 316, that may be executed by the one or more processors 310. The memory may be of any type capable of storing information accessible by the processor, including non -transitory and tangible computer-readable mediums containing computer readable instructions such as a hard-drive, memory card, ROM, RAM, DVD or other optical disks, as well as other write-capable and read-only memories. The system and method may include different combinations of the foregoing, whereby different portions of the data 314 and instructions 316 are stored on different types of media. In the memory of each node, such as memory 312 of HAP 114, a forwarding information base or forwarding table may be stored that indicate how signals received at each node should be forwarded, or transmitted. For example, the forwarding table stored in memory 312 may indicate that a signal received from terrestrial tower 110 should be forwarded to terrestrial tower 112.
[0027] Data 314 may be retrieved, stored or modified by the one or more processors 310 in accordance with the instructions 316. For instance, although the system and method are not limited by any particular data structure, the data 314 may be stored in computer registers, in a relational database as a table having a plurality of different fields and records, XML documents or flat files. The data 314 may also be formatted in any computer-readable format such as, but not limited to, binary values or Unicode. By further way of example only, image data may be stored as bitmaps comprised of grids of pixels that are stored in accordance with formats that are compressed or uncompressed, lossless (e.g., BMP) or lossy (e.g., JPEG), and bitmap or vector-based (e.g., SVG), as well as computer instructions for drawing graphics. The data 314 may comprise any information sufficient to identify the relevant information, such as numbers, descriptive text, proprietary codes, references to data stored in other areas of the same memory or different memories (including other network locations) or information that is used by a function to calculate the relevant data.
[0028] The instructions 316 may be any set of instructions to be executed directly (such as machine code) or indirectly (such as scripts) by the one or more processors 310. For example, the instructions 316 may include the given protocol architecture for the mobile network of which the node is a part. The given protocol architecture may include a split architecture between a central unit and a distributed unit. In addition, the given protocol architecture may define a control plane, a user plane, or other protocol layers. The given protocol architecture may also include an interface that defines a plurality of messages for use in communication between the protocol layers. The instructions 316 may be stored as computer code on the computer-readable medium. In that regard, the terms "instructions" and "programs" may be used interchangeably herein. The instructions 316 may be stored in object code format for direct processing by the one or more processors 310, or in any other computer language including scripts or collections of independent source code modules that are interpreted on demand or compiled in advance. Functions, methods and routines of the instructions 316 are explained in more detail below.
[0029] The one or more transceivers 320 may include at least one wireless transceiver. The at least one wireless transceiver may include one or more high-power light-emitting diodes (LEDs) or a laser systems configured to transmit an optical signal for free-space optical communications. Other types of free-space communication are possible. Further, in order to receive an optical signal from another node, the at least one wireless transceiver may include one or more optical receivers. For nodes with fiber or cable connections, such as second terrestrial tower 112, the one or more transceivers 320 may also include at least one transceiver configured to communicate via a fiber or cable connection.
[0030] The one or more antennas 322 may each provide coverage for one or more sectors with different beams. In some implementations, a steering mechanism, such as a gimbal, may be configured to point an antenna of one or more antennas 322 in a pointing direction. To form a wireless link between two nodes, such as the node associated with the HAP 114 and the node associated with the first terrestrial tower 110, the wireless transceivers and/or the antennas of the respective nodes can be controlled to point in the direction of one another so that data can be sent and received between the nodes.
[0031] As further shown in FIGURE 3, the UE 152 associated with user 150 may be a personal computing device or a server with one or more processors 350, memory 352, data 354, and instructions 356 similar to those described above with respect to the one or more processors 310, memory 312, data 314, and instructions 316. Personal computing devices may include a personal computer that has all of the components normally used in connection with a personal computer such as a central processing unit (CPU), memory (e.g. , RAM and internal hard drives) storing data and instructions, an electronic display (e.g., a monitor having a screen, a small LCD touch-screen, a projector, a television, or any other electrical device that is operable to display information), user input (e.g., a mouse, keyboard, touch-screen or microphone), camera, speakers, a network interface device, and all of the components used for connecting these elements to one another. Personal computing devices may also include mobile devices such as PDAs, cellular phones, and the like. Indeed, UE 152 may be any device capable of processing instructions and transmitting data to and from humans and other computers including general purpose computers, network computers lacking local storage capability, and set-top boxes for televisions. In some embodiments, UE may be associated with one or more self-defined network (SDN) applications and may have one or more northbound interface (NBI) drivers.
[0032] The network topology may change as one or more HAP nodes move relative to other nodes and/or relative to the ground. Accordingly, the network may apply a mesh protocol to update the state of the network as the topology of the network changes. The network may also implement station keeping functions using winds and altitude control or lateral propulsion to help provide a desired network topology. For example, station-keeping may involve some or all of HAP nodes of the network maintaining and/or moving into a certain position relative to one or more other balloons in the network (and possibly in a certain position relative to a terrestrial node or service area). As part of this process, each HAP node may implement station-keeping functions to determine its desired positioning within the desired topology, and if necessary, to determine how to move to and/or maintain the desired position. For instance, the HAP nodes may move in response to riding a wind current, or may move in a circular or other pattern as they station keep over a region of interest.
[0033] The desired topology may vary depending upon the particular implementation and whether or not the HAP nodes are continuously moving. In some cases, HAP nodes may implement station keeping to provide a substantially uniform topology where the HAP nodes function to position themselves at substantially the same distance (or within a certain range of distances) from adjacent nodes in the network. Alternatively, the network may have a non-uniform topology where HAP nodes are distributed more or less densely in certain areas, for various reasons. As an example, to help meet the higher bandwidth demands, HAP nodes may be clustered more densely over areas with greater demand (such as urban areas) and less densely over areas with lesser demand (such as over large bodies of water). In addition, the topology of an example network may be adaptable allowing HAP nodes to adjust their respective positioning in accordance with a change in the desired topology of the network. [0034] In some implementations, the network can be an SDN that is controlled by an SDN controller. The network controller may be located at one of the network nodes or at a separate platform, such as, for example, in a datacenter. The nodes of the network, including nodes 110, 112, 114 may be configured to communicate with one another using the steerable transceivers, such as the one or more transceivers 320. As the HAPs in the network, such as HAP 114, move with respect to other nodes in the network, such as terrestrial towers 110, 112, some network links may become infeasible due to range of the transceivers or obstacles between the nodes. Thus, the configuration of the network may require regular (i.e., periodic) or irregular reconfiguration using the network controller to maintain connectivity and to satisfy determined network flows.
EXAMPLE HIGH-ALTITUDE PLATFORMS
[0035] The HAP 114 of FIGURE 1 may be a high -altitude balloon or other type of HAPs that are deployed in the stratosphere. As an example, the HAP nodes in the network may generally be configured to operate at stratospheric altitudes, e.g., between 50,000 ft and 70,000 ft or more or less, in order to limit the HAPs' exposure to high winds and interference with commercial airplane flights. In order for the HAPs to provide a reliable mesh network in the stratosphere, where winds may affect the locations of the various HAPs in an asymmetrical manner, the HAPs may be configured to move latitudinally and/or longitudinally relative to one another by adjusting their respective altitudes, such that the wind carries the respective balloons to the respectively desired locations. Lateral propulsion may also be employed to affect the balloon’s path of travel.
[0036] In order to change lateral positions or velocities, the platform may include a lateral propulsion system. FIGURE 4 illustrates one example configuration 400 of a balloon platform with propeller- based lateral propulsion, which may represent HAP 114 of FIGURE 1. As shown, the example 400 includes an envelope 402, a payload 404 and a down connect member 406 disposed between the envelope 402 and the payload 404. At least one gore panel forms the envelope, which is configured to maintain pressurized lifting gas therein. For instance, the balloon may be a superpressure balloon. A top plate may be disposed along an upper section of the envelope, while a base plate may be disposed along a lower section of the envelope opposite the top place. The coupling member 406 may connect the payload 404 with the base plate.
[0037] The envelope 402 may take various shapes and forms. For instance, the envelope 402 may be made of materials such as polyethylene, mylar, FEP, rubber, latex or other thin film materials or composite laminates of those materials with fiber reinforcements imbedded inside or outside. Other materials or combinations thereof or laminations may also be employed to deliver required strength, gas barrier, RF and thermal properties. Furthermore, the shape and size of the envelope 402 may vary depending upon the particular implementation. Additionally, the envelope 402 may be filled with different types of gases, such as air, helium and/or hydrogen. Other types of gases, and combinations thereof, are possible as well. Shapes may include typical balloon shapes like spheres and “pumpkins”, or aerodynamic shapes that are symmetric, provide shaped lift, or are changeable in shape. Lift may come from lift gasses (e.g., helium, hydrogen), electrostatic charging of conductive surfaces, aerodynamic lift (wing shapes), air moving devices (propellers, flapping wings, electrostatic propulsion, etc.) or any hybrid combination of lifting techniques.
[0038] The payload 404 may include the one or more processors 310, the memory 312, the one or more transceivers 320, and the one or more antennas 322 of HAP 114. The payload 404 may additionally include a positioning system. The positioning system could include, for example, a global positioning system (GPS), an inertial navigation system, and/or a star-tracking system. The positioning system may additionally or alternatively include various motion sensors (e.g., accelerometers, magnetometers, gyroscopes, and/or compasses).
[0039] A navigation system may additionally be included in the payload. The navigation system may implement station-keeping functions to maintain position within and/or move to a position in accordance with a desired topology or other service requirement. In particular, the navigation system may use wind data (e.g., from onboard and/or remote sensors) to determine altitudinal and/or lateral positional adjustments that result in the wind carrying the balloon in a desired direction and/or to a desired location. Lateral positional adjustments may also be handled directly by a lateral positioning system that is separate from the payload. Alternatively, the altitudinal and/or lateral adjustments may be computed by a central control location and transmitted by a ground based, air based, or satellite based system and communicated to the high-altitude balloon. In other embodiments, specific balloons may be configured to compute altitudinal and/or lateral adjustments for other balloons and transmit the adjustment commands to those other balloons. [0040] The navigation system is able to evaluate data obtained from onboard navigation sensors, such as an inertial measurement unit (IMU) and/or differential GPS, received data (e.g., weather information), and/or other sensors such as health and performance sensors (e.g., a force torque sensor) to manage operation of the balloon’s systems. When decisions are made to activate the lateral propulsion system, for instance to station keep, the navigation system then leverages received sensor data for position, wind direction, altitude and power availability to properly point the propeller and to provide a specific thrust condition for a specific duration or until a specific condition is reached (e.g., a specific velocity or position is reached, while monitoring and reporting overall system health, temperature, vibration, and other performance parameters).
[0041] Cables or other wiring between the payload 404 and the envelope 402 may be run within the down connect member 406. One or more solar panel assemblies 408 may be coupled to the payload 404 or another part of the balloon platform. The payload 404 and the solar panel assemblies 408 may be configured to rotate about the down connect member 406 (e.g., up to 360° rotation), for instance to align the solar panel assemblies 408 with the sun to maximize power generation. Example 400 also illustrates an example lateral propulsion system 410. While this example of the lateral propulsion system 410 is one possibility, the location could also be fore and/or aft of the payload section 404, or fore and/or aft of the envelope section 402, or any other location that provides the desired thrust vector. [0042] Other than balloons, HAP nodes of the network may include drones flying routes in an autonomous manner, carrying cameras for aerial photography, and transporting goods from one place to another. The terms “unmanned aerial vehicle (UAV)” and “flying robot” are often used as synonyms for a drone. The spectrum of applications is broad, including aerial monitoring of industrial plants and agriculture fields as well as support for first time responders in case of disasters. For some applications, it is beneficial if a team of drones rather than a single drone is employed. Multiple drones can cover a given area faster or take photos from different perspectives at the same time.
EXAMPLE METHODS
[0043] In addition to the operations described above and illustrated in the figures, various operations will now be described. It should be understood that the following operations do not have to be performed in the precise order described below. Rather, various steps can be handled in a different order or simultaneously, and steps may also be added or omitted.
[0044] A first System Information Block (SIB), or SIB1, may be defined to carry information that is critical to initiating communication with a node of the network (e.g., access information related to a Random Access Channel (RACH)). In some implementations, SIB1 may be transmitted periodically by one or more processors of a HAP node, such as one or more processors 310 of HAP node 114, to a geographic region using a fixed schedule. The fixed schedule may be a repeated interval, such as every 80 milliseconds or more or less, or other time frame that is defined by the network standard.
[0045] A first indication of location information may be included in SIB1 to alert a UE in the geographic region, such as UE 152 that additional location information is needed in order to form a connection with the HAP node. For example, the first indication of location information may be added in an optional field of SIB 1 and include an identification of the HAP node as a moving base station. The first indication of location information may also specify in which SIB the additional location information is. Given the amount of other information included in SIB1, the amount of total location information of the HAP node, and size constraints of SIB 1 , the amount of location information included in SIB 1 may be kept to a minimum. For example, the size of this first indication may be one bit. [0046] The additional location information, or second indication of location information, may be included in another SIB different from SIB1, or SIB#, that is transmitted from the HAP node to the UE. The size of the additional information may be greater than the first indication of location information. The additional location information may include a current location of the HAP node at a current time. For example, the current location may be a latitude, longitude, and altitude of the HAP node.
[0047] The additional location information may additionally or alternatively include an identification for the additional location information, a timestamp, an identification for the HAP node, an address for the HAP node, a trajectory or a predicted motion of the HAP node, a speed of the HAP node, a wind direction at a given altitude, and/or a wind speed at a given altitude . In scenarios when the HAP node travels in a regular fixed pattern, the additional location information may include the entire regular fixed pattern. In some implementations, the additional location information may include an expiration time that indicates when at least one of the additional location information is no longer valid. The expiration information may allow a UE to determine when updated additional location information is needed. Any SIB# received prior to the expiration time may not be process (or read) by the UE since the additional location information prior to the expiration time is still valid.
[0048] As the HAP node moves, the additional location information may be updated in the memory of the UE with location information based on a new current location of the HAP node at a new current time. The updated additional location information may be assigned a new identification so a UE can quickly identify whether the additional location information has changed from previously received additional location information. When the identification of the additional location information is the same as for previously received additional location information, the UE need not further process the additional location information. In an alternative implementation, the updated additional location information may be stored at the memory of the HAP node and then transmitted to the UE. The updates to the additional location information may occur at predefined regular intervals or at points in time defined by a motion of the HAP node, such as a speed at which the HAP node travels. [0049] For example, for a HAP node that is a satellite, the SIB# may include the following: name: two_line_element type: scalar compound field subfield: line_l (ASCII string with max length of 70 characters) subfield: line_2 (ASCII string with max length of 70 characters)
[0050] In this example, a two-line element set (TLE) is a data format encoding a list of orbital elements of an Earth-orbiting object for a given point in time. The TLE element set included in the SIB# for a satellite may encode the orbiting pattern of the satellite, from which a UE is able to derive the position of the satellite at a given point in time.
[0051] For other types of HAP nodes, such as balloons or aircraft, the SIB# may include the following: name: timestamped_coordinates type: array of compound fields [max length of 4] subfield[0]: longitude_deg (double precision) subfield[0]: latitude_deg (double precision) subfield[0]: height m (double precision) subfield[0]: speed_mps subfield[0]: timestamp (uint64) subfield[0]: timestamp validity (uint64)
[0052] Cartographic coordinates that define a position of the HAP node at a given point in time are included in the SIB#. In this example, the cartographic coordinates may be relative to the WGS84 reference ellipsoid of the Earth’s surface. For example, longitude and latitude may be in degrees and height may be the distance, in meters, above the WGS84 ellipsoid surface. Speed in this example may be in meters per second. Timestamp is the given point in time at which the cartographic coordinates are valid. In this example, the timestamp may be a count of microseconds since the Unix epoch based and may presume that leapseconds are smeared. A timestamp validity defines a period of time from the timestamp after which the timestamped coordinates are too old (i.e., expire). This example SIB# may also be applied to network nodes that are high speed rail platforms or terrestrial platforms.
[0053] Optionally included in the SIB# for HAP nodes are: name: aircraft id type: scalar compound field subfield: icao_aircraft_address (uint32) subfield: aircraft identification (ASCII string with max length of 7 chars)
[0054] In some implementations, the SIB# is also transmitted periodically by the one or more processors of the HAP node using a fixed schedule. The periodicity of the SIB# may be based on a type of HAP node, such as based on the speed of the HAP node’s motion. For example, the periodicity of a SIB# for a first HAP node may be smaller (i.e., more frequent) than that of a SIB# for a second HAP node when the first HAP node moves faster than the second HAP node.
[0055] In alternative implementations, the SIB# is transmitted in response to a request from the UE. This implementation may be utilized when the UE has previous location information for the HAP node such that the UE has an estimated location of the HAP node based on the previous location information to which to send the request. The request may be sent from the UE to the HAP node after the UE receives the first indication in SIB 1. The request may be included in an uplink signal, such as Physical Random Access Channel (PRACH) signal.
[0056] Having received the SIB 1 and SIB# for the HAP node, the UE may establish a communication link with the HAP node and/or maintain the communication link with the HAP node by compensating for the HAP node using the location information. The communication link may serve as an access link for the UE to the HAP node and the larger access network. For example, after SIB 1 and SIB# is received at UE 152 from HAP node 114, communication link may be formed between UE 152 and HAP node 114, , such as along path 128. The UE 152 may use the communication link to access HAP node 114 and network 200.
[0057] After a period of time elapses from receipt of the SIB#, the UE may determine that at least one of the additional location information has expired. The period of time may be determined based on the expiration time in the additional location information. When the additional location information has expired, the UE may reread the SIB# in the memory of the UE, which is may now be the updated SIB# including the updated additional information received from a transmission or broadcast from the HAP node. Alternatively, the UE may request an updated SIB# for the HAP node. In response to the request for the updated SIB#, the HAP node may send another SIB# with updated additional location information.
[0058] Alternatively, other types of communication blocks may be used instead of SIBs.
[0059] In some implementations, SIB 1 may not include a first indication of location information. In this scenario, several alternate possibilities exist. In one alternative, the UE may always check for SIB# and the existence of a second indication of location information. If SIB# is not found, then the UE may assume that it is not connecting to a HAP node and proceed with forming a communication link accordingly. If SIB# is found, then the UE uses the additional location information to form a communication link with the HAP node. In another alternative, the UE may be configured with HAP- specific geographical information (such as Global Positioning System coordinates, list of tracking area identities, etc.). The UE may then check for SIB# only when it determines that its location is in a geographic area specified by the HAP-specific configuration. The HAP-specific configuration can be pre-provisioned in the UE, or provisioned and updated by Radio Resource Control (RRC) and/or Non- Access Stratum (NAS) procedures. In yet another alternative, the UE check for the SIB# after receiving a third indication that the HAP node is likely available in a particular location from another node of the network, a network controller, or a central server. For example, a terrestrial node in communication with the HAP node may broadcast at least some location information associated with the HAP node in the third indication such that the UE may be able to initiate a communication with the HAP node. The third indication may also include a physical cell identifier (PCI) of the HAP node. When the third indication does not include sufficient location information for the HAP node, the UE may check for the SIB# by trying different timing offsets in order to connect with the HAP node.
[0060] The technology described herein allows for an efficient means to communicate where a moving HAP node is to a UE so the UE is able to locate and stay connected with the moving HAP node for communication purposes. The technology utilizes System Information Blocks that are already used in LTE or 5G NR systems and customizes a few SIBs to effectively communicate that (1) the HAP node is in motion and (2) the location information of the HAP node. While useful for HAP nodes, this technology is also useful for other types of moving or non-moving nodes.
[0061] FIGURE 5 shows a flow diagram 500 of a method in accordance with aspects of the technology. At block 502, one or more processors 310 of HAP node 114 may transmit a first indication of location information in a first SIB to a geographic region. The geographic region may include a UE 152. The UE 152 may receive the first SIB with the first indication of location information and await additional location information. At block 504, the one or more processors 310 may transmit a second indication of location information in a second SIB to the UE in the geographic region. The UE may receive the second SIB with the second indication of location information, which includes the additional location information. At block 506, the one or more processors 310 may establish a communication link with the UE 152 according to the first indication of location information and the second indication of location information. The communication link may allow UE 152 to access a network through HAP node 114, such as network 200.
[0062] Unless otherwise stated, the foregoing alternative examples are not mutually exclusive, but may be implemented in various combinations to achieve unique advantages. As these and other variations and combinations of the features discussed above can be utilized without departing from the subject matter defined by the claims, the foregoing description of the aspects should be taken by way of illustration rather than by way of limitation of the subject matter defined by the claims. In addition, the provision of the examples described herein, as well as clauses phrased as "such as," "including" and the like, should not be interpreted as limiting the subject matter of the claims to the specific examples; rather, the examples are intended to illustrate only one of many possible aspects. Further, the same reference numbers in different drawings can identify the same or similar elements.

Claims

1. A method comprising: transmitting, by one or more processors of a high-altitude platform (HAP) node, a first indication of location information in a first System Information Block (SIB) to a geographic region; transmitting, by the one or more processors, a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establishing, by the one or more processors, a communication link with the UE according to the first indication of location information and the second indication of location information.
2. The method of claim 1, wherein the second indication of location information is a greater amount of data than the first indication of location information.
3. The method of claim 1, wherein the first indication of location information includes an identification of the HAP node as a moving base station.
4. The method of claim 1, wherein the second indication of location information includes a current location of the HAP node.
5. The method of claim 4, wherein the current location of the HAP node includes a longitude, a latitude, a height, and a timestamp.
6. The method of claim 1, wherein the first SIB is transmitted at regular intervals to the geographic region.
7. The method of claim 6, wherein the second SIB is transmitted at regular intervals to the geographic region.
8. The method of claim 6, further comprising: receiving, from the UE in the geographic region, a request for the second SIB based on the first
SIB; wherein the transmitting of the second SIB occurs after the receiving of the request.
9. A system of a high-altitude platform (HAP) comprising: one or more transceivers; and one or more processors configured to: transmit a first indication of location information in a first System Information Block (SIB) to a geographic region; transmit a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establish, using the one or more transceivers, a communication link with the UE according to the first indication of location information and the second indication of location information.
10. The system of claim 9, wherein the second indication of location information is a greater amount of data than the first indication of location information.
11. The system of claim 9, wherein the first indication of location information includes an identification of the HAP as a moving base station.
12. The system of claim 9, wherein the second indication of location information includes a current location of the HAP.
13. The system of claim 12, wherein the current location of the HAP includes a longitude, a latitude, a height, and a timestamp.
14. The system of claim 9, wherein the first SIB is transmitted at regular intervals to the geographic region.
15. The system of claim 14, wherein the second SIB is transmitted at regular intervals to the geographic region.
16. The system of claim 14, wherein the one or more processors are further configured to: receive, from the UE in the geographic region, a request for the second SIB based on the first
SIB; wherein the one or more processors are configured to transmit the second SIB after the receiving of the request.
17. A non-transitory, computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors of a high-altitude platform (HAP) node to perform a method, the method comprising: transmitting a first indication of location information in a first System Information Block (SIB) to a geographic region; transmitting a second indication of location information in a second SIB to a user equipment (UE) in the geographic region; and establishing a communication link with the UE according to the first indication of location information and the second indication of location information.
18. The medium of claim 17, wherein the second indication of location information is a greater amount of data than the first indication of location information.
19. The medium of claim 17, wherein the first indication of location information includes an identification of the HAP node as a moving base station, and the second indication of location information includes a current location of the HAP node.
20. The medium of claim 17, wherein the first SIB is transmitted at regular intervals to the geographic region.
PCT/US2021/070176 2020-02-21 2021-02-22 Distribution of location information to aid user equipment link with moving non-terrestrial network nodes WO2021168485A1 (en)

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