PATENT DOCUMENT

Publication Number: US-11493621-B2
Application Number: US-201916674993-A
Country: US
Kind Code: B2

Title: Secure multicast/broadcast ranging

Abstract:
Methods performed by a first device. The methods include transmitting a first ranging poll to a plurality of second devices, receiving a polling response message from each of at least a first subset of the second devices, determining a propagation delay for each of the received polling response messages and determining a distance to each of the first subset of the second devices based on at least the respective propagation delays. The methods further include receiving a ranging poll from a second device, wherein the ranging poll is one of a multicast transmission or a broadcast transmission, determining a type of response to be transmitted to the second device based on at least a capability of the first device and transmitting a response of the determined type to the second device.

Claims:
The invention claimed is: 
     
       1. A method, comprising:
 at a first device:
 transmitting a first ranging poll to a plurality of second devices, wherein the first ranging poll includes one of an identification of a type of ranging operation, a number of ranging rounds to be performed, a duration of a ranging round, a number of response slots, a ranging round counter, a pointer to a next ranging poll, an indication of whether the polling response messages are scheduled, a slot assignment for the polling response messages or a maximum number of attempts for each polling response message; 
 receiving a polling response message from each of at least a first subset of the second devices; 
 determining a respective propagation delay for each of the received polling response messages; and 
 determining a respective distance to each of the first subset of the second devices based on at least the respective propagation delays. 
 
 
     
     
       2. The method of  claim 1 , further comprising:
 transmitting a second ranging poll to the plurality of second devices; 
 receiving a time stamp response message from each of at least a second subset of the second devices; and 
 determining a respective distance to each of the second subset of the second devices based on at least the respective time stamp response message. 
 
     
     
       3. The method of  claim 1 , further comprising:
 transmitting a pre-poll message including ranging configuration information to the plurality of second devices. 
 
     
     
       4. The method of  claim 1 , further comprising:
 transmitting time stamp information to the plurality of second devices. 
 
     
     
       5. The method of  claim 1 , wherein the first device and the plurality of second devices are communicatively coupled via an ultra-wideband (UWB) network. 
     
     
       6. The method of  claim 1 , wherein the transmitting the first ranging poll to the plurality of second devices is a broadcast transmission, wherein the first device and each of the plurality of second devices share a common key to exchange station-to-station messages. 
     
     
       7. The method of  claim 1 , wherein the transmitting the first ranging poll to the plurality of second devices is a multicast transmission based on the first device including information corresponding to a number of the plurality of second devices and an identity of each of the plurality of secondary devices. 
     
     
       8. A device, comprising:
 a transceiver configured to transmit a first ranging poll to a plurality of second devices and receive a polling response message from each of at least a first subset of the second devices, wherein the first ranging poll includes one of an identification of a type of ranging operation, a number of ranging rounds to be performed, a duration of a ranging round, a number of response slots, a ranging round counter, a pointer to a next ranging poll, an indication of whether the polling response messages are scheduled, a slot assignment for the polling response messages or a maximum number of attempts for each polling response message; and 
 a processor configured to determine a respective propagation delay for each of the received polling response messages and determine a respective distance to each of the first subset of the second devices based on at least the respective propagation delays. 
 
     
     
       9. The device of  claim 8 , wherein the transceiver is further configured to transmit a second ranging poll to the plurality of second devices and receive a time stamp response message from each of at least a second subset of the second devices, wherein the processor is further configured to determine a respective distance to each of the second subset of the second devices based on at least the respective time stamp response message. 
     
     
       10. The device of  claim 8 , wherein the first device and the plurality of second devices are communicatively coupled via an ultra-wideband (UWB) network. 
     
     
       11. The device of  claim 8 , wherein the transmitting the first ranging poll to the plurality of second devices is a broadcast transmission, wherein the first device and each of the plurality of second devices share a common key to exchange station-to-station messages. 
     
     
       12. The device of  claim 8 , wherein the transmitting the first ranging poll to the plurality of second devices is a multicast transmission based on the first device including information corresponding to a number of the plurality of second devices and an identity of each of the plurality of secondary devices. 
     
     
       13. The device of  claim 8 , wherein the transceiver is further configured to transmit a pre-poll message including ranging configuration information to the plurality of second devices. 
     
     
       14. The device of  claim 8 , wherein the transceiver is further configured to transmit time stamp information to the plurality of second devices. 
     
     
       15. A processor of a first device configured to perform operations comprising:
 transmitting a first ranging poll to a plurality of second devices, wherein the first ranging poll includes one of an identification of a type of ranging operation, a number of ranging rounds to be performed, a duration of a ranging round, a number of response slots, a ranging round counter, a pointer to a next ranging poll, an indication of whether the polling response messages are scheduled, a slot assignment for the polling response messages or a maximum number of attempts for each polling response message; 
 receiving a polling response message from each of at least a first subset of the second devices; 
 determining a respective propagation delay for each of the received polling response messages; and 
 determining a respective distance to each of the first subset of the second devices based on at least the respective propagation delays. 
 
     
     
       16. The processor of  claim 15 , wherein the operations further comprise:
 transmitting a second ranging poll to the plurality of second devices; 
 receiving a time stamp response message from each of at least a second subset of the second devices; and 
 determining a respective distance to each of the second subset of the second devices based on at least the respective time stamp response message. 
 
     
     
       17. The processor of  claim 15 , wherein the operations further comprise:
 transmitting a pre-poll message including ranging configuration information to the plurality of second devices. 
 
     
     
       18. The processor of  claim 15 , wherein the first device and the plurality of second devices are communicatively coupled via an ultra-wideband (UWB) network. 
     
     
       19. The processor of  claim 15 , wherein the transmitting the first ranging poll to the plurality of second devices is one of (i) a broadcast transmission, wherein the first device and each of the plurality of second devices share a common key to exchange station-to-station messages or (ii) a multicast transmission based on the first device including information corresponding to a number of the plurality of second devices and an identity of each of the plurality of secondary devices. 
     
     
       20. The processor of  claim 15 , wherein the operations further comprise:
 transmitting time stamp information to the plurality of second devices.

Description:
BACKGROUND INFORMATION 
     The IEEE 802.15.4 standard specifies a physical layer (PHY) and a media access control (MAC) layer for operation of low-rate WPANs (LR-WPANs). These types of networks are typically referred to as Ultra-Wideband (UWB) networks. UWB networks may connect wireless electronic devices in various arrangements. In one example, a UWB network may comprise a primary device and one or more secondary devices. The devices of the UWB network may perform various functionalities with respect to the other devices connected to the UWB network. 
     SUMMARY 
     Exemplary embodiments include a method performed by a first device. The method includes receiving a ranging poll from a second device, wherein the ranging poll is one of a multicast transmission or a broadcast transmission, determining a type of response to be transmitted to the second device based on at least a capability of the first device and transmitting a response of the determined type to the second device. 
     Further exemplary embodiments include a device having a transceiver and a processor. The transceiver is configured to transmit a first ranging poll to a plurality of second devices and receive a polling response message from at least a first subset of the second devices. The processor is configured to determine a propagation delay for each of the received polling response messages and determine a distance to each of the first subset of the second devices based on at least the respective propagation delays. 
     Still further exemplary embodiments include a method performed by a first device. The method includes receiving a ranging poll from a second device, wherein the ranging poll is one of a multicast transmission or a broadcast transmission, determining a type of response to be transmitted to the second device based on at least a capability of the first device and transmitting a response of the determined type to the second device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exemplary network arrangement according to various exemplary embodiments. 
         FIG. 2  shows an exemplary wireless device according to various exemplary embodiments. 
         FIG. 3  shows a first exemplary timing diagram for a broadcast ranging operation according to various exemplary embodiments. 
         FIG. 4  shows a second exemplary timing diagram for a multicast ranging operation according to various exemplary embodiments. 
         FIG. 5  shows an exemplary MAC Information Element (IE) according to various exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The exemplary embodiments may be further understood with reference to the following description and the related appended drawings, wherein like elements are provided with the same reference numerals. The exemplary embodiments are related to a system and method for performing a secure broadcast or multicast ranging procedure in a UWB network. It may be desirable for a primary device in a wireless personal area network (WPAN) to determine a distance to one or more secondary devices. The exemplary embodiments describe a ranging procedure that allows the primary device to avoid an individual ranging procedure for each of the secondary devices, thereby decreasing a number of packets exchanged in the UWB network during ranging operations. 
     The exemplary embodiments are described with respect to devices that may operate according to the IEEE 802.15.4 standard. However, it should be understood that the exemplary embodiments of the ranging operation may be used by devices using any UWB protocol. In addition, the terms wireless personal area network (WPAN) and Ultra-Wideband (UWB) network are used interchangeably throughout this description and those skilled in the art will understand the general characteristics of such networks. 
       FIG. 1  shows an exemplary network arrangement  100  according to various exemplary embodiments. The exemplary network arrangement  100  includes a primary device  105  and a plurality of secondary devices  110 - 130 . The primary device  105  and the secondary devices  110 - 130  may be any type of electronic component that is configured to operate within a UWB network, e.g., mobile phones, tablet computers, smartphones, phablets, embedded devices, wearable devices, Cat-M devices, Cat-M1 devices, MTC devices, eMTC devices, other types of Internet of Things (IoT) devices, access points, etc. It should be understood that an actual network arrangement may include any number of secondary devices. The example of five secondary devices  110 - 130  is only provided for illustrative purposes. It should also be understood that any of the devices  105 - 130  may be designated a primary device and similarly, any of the devices  105 - 130  may be designated as a secondary device for a particular ranging operation. That is, the device that initiates the ranging operation may be designated as the primary device. 
     The primary device  105  and the secondary devices  110 - 130  may be configured to communicate over the UWB network. However, it should be understood that the primary device  105  and the secondary devices  110 - 130  may also communicate with other types of wireless networks (cellular or non-cellular) and may also communicate using a wired connection. With regard to the exemplary embodiments, the primary device  105  and the secondary devices  110 - 130  may communicate over the UWB network to, among other functionalities, transmit or receive data. 
       FIG. 2  shows an exemplary wireless device  105  according to various exemplary embodiments. It should be understood that the exemplary wireless device  105  of  FIG. 2  may also represent any of the other wireless device  110 - 130  of the network arrangement  100 . The wireless device  105  may include a processor  205 , a memory arrangement  210 , a display device  215 , an input/out (I/O)  220 , a transceiver  225 , and other components  230 . The other components  230  may include, for example, an antenna, an audio input device, an audio output device, a battery, a data acquisition device, ports to electrically connect to other electronic devices, etc. 
     The processor  205  may be configured to execute a plurality of applications of the device  105 . In one exemplary embodiment, an application may include a ranging application  235  as will be described in greater detail below. The described functionalities of the wireless device  105  being represented as an application (e.g., a program) executed by the processor  205  is only exemplary. The functionality associated with the applications may also be implemented as a separate incorporated component of the wireless device  105  or may be a modular component coupled to the wireless device  105 , e.g., an integrated circuit with or without firmware. In addition, in some wireless devices, the functionality described for the processor  205  is split among two processors, a baseband processor and an application processor. The exemplary embodiments may be implemented in any of these or other configurations of a wireless device. 
     The transceiver  225  may be a hardware component configured to transmit and/or receive data. For example, the transceiver  225  may enable communication with other electronic devices directly or indirectly through one or more networks based upon a protocol and an operating frequency of the network. The transceiver  225  may operate on a variety of different frequencies or channels (e.g., set of consecutive frequencies). Thus, one or more antennas (not shown) coupled with the transceiver  225  may enable the transceiver  225  to communicate with other wireless devices (e.g., wireless devices  110 - 130 ) via a UWB network. 
     The exemplary embodiments describe the primary device  105  determining a distance to and/or a location of each of the plurality of secondary devices  110 - 130  using a ranging operation. Throughout this description, the term “distance” will be used to refer to the distance between devices and/or the location of the secondary device  110 - 130  either relative to the primary device  105  or an absolute location within a particular space. Three exemplary ranging modes are described. A single node ranging mode is utilized for determining a distance to a single secondary device, e.g. secondary device  110 . A multicast ranging mode is utilized for determining a distance to a plurality of secondary devices, e.g. secondary devices  110 - 130 , when the number and identity of the secondary devices  110 - 130  are known to the primary device  105 . For example, in the network arrangement  100 , the number of secondary devices is five. The identity of the secondary devices  110 - 130  may be known to the primary device  105  through any number of manners, e.g. previous data exchanges, previous ranging operations, etc. A broadcast ranging mode is utilized for determining a distance to a plurality of secondary devices, e.g. secondary devices  110 - 130 , when the number of secondary devices and the identity of each of the secondary devices are not known to the primary device  105 . However, even when the identities of the secondary devices  110 - 130  are not known to the primary device  105 , the devices  105 - 130  may share a common key that may be used to receive station-to-station messages. For example, keys may be shared via an upper layer protocol either over the UWB network or a sideband channel. 
     The ranging application  235  may implement one or more of these ranging modes. In the below description, the operation of the exemplary multicast ranging mode and broadcast ranging mode will be described in detail. The single node ranging mode operation will not be described as that mode will operate in accordance with conventional ranging operations. 
       FIG. 3  shows a first exemplary timing diagram for a broadcast ranging operation  300  according to various exemplary embodiments. The broadcast ranging operation  300  will be described with reference to the network arrangement  100  of  FIG. 1 . As shown in  FIG. 3 , one exemplary ranging round  350  is illustrated. As will be described in greater detail below, there may be multiple rounds of ranging operations performed. 
     In the ranging round  350 , the primary device  105  may transmit a pre-poll message  305  that includes ranging configuration information for the secondary devices  110 - 130 . The pre-poll message  305  is not required to be transmitted in every ranging round. For example, the ranging round  350  may be a subsequent ranging round and a previous pre-poll message including the configuration information may have been sent by the primary device  105  and received by the secondary devices  110 - 130 . Thus, the same configuration information is not required to be sent multiple times. In one example, the ranging configuration information may remain valid until a next pre-poll message is transmitted. In another example, the configuration information may be included in the ranging poll  210  (described below). In a further example, the configuration information may be included in other messages exchanged between the wireless devices  105 - 130 , either via the UWB network or another network/protocol. In any case, the secondary devices  110 - 130  connected via the UWB network will receive the ranging configuration information. 
     The primary device  105  may then broadcast a first ranging poll  310  to the secondary devices  110 - 130  via the UWB network. The first ranging poll  310  may include various information allowing the secondary devices  110 - 130  to respond to the poll. This information of the first ranging poll  310  may be included in a MAC information element (IE)  500 , as will be described in further detail with respect to  FIG. 5 . 
     The secondary devices  110 - 130  may contend for available polling response slots and respond to the first ranging poll  310  by transmitting polling response messages  315   a - c  to the primary device  105 . The polling response slots are indicated as R 1 , R 2  . . . R N , wherein N is a number of available slots. As will be described below, the number of available slots N may be configurable by the primary device  105 . 
     After receipt of the polling response messages  315   a - c  by the primary device  105 , it may be considered that the ranging round  350  is complete. For example, the primary device  105  may have received sufficient information in the polling response messages  315   a - c  to determine the distance to the secondary devices  110 - 130 . However, a second ranging poll  320  of the same ranging round  350  may also be used. For example, if precise ranging with clock drift cancellation is used, the second ranging poll  320  and corresponding responses (described below) may be used. In another example, when a time stamp is not included in the polling response messages  315   a - c , the primary device  105  may not be able to derive the propagation delay inherent in sending messages across a distance. For example, if the precise timing is known for the transmission of the polling response message by one of the secondary devices  110 - 130  and for the reception of the polling response message by the primary device  105 , then the primary device  105  can derive the distance between the devices. Thus, when any one of the secondary devices  110 - 130  is not capable of including time stamps in the polling response messages  315   a - c , the second ranging poll  320  may be used. 
     When the second ranging poll  320  is used, the primary device  105  broadcasts a second ranging poll  320  to the secondary devices  110 - 130  via the UWB network. The second ranging poll  320  may be substantially similar to the first ranging poll  310 , with appropriate modifications to the MAC IE  400  to indicate the expected response is a timestamp response. 
     The secondary devices  110 - 130  may then contend for available time stamp reporting slots and respond to the second ranging poll  320  by transmitting time stamp response messages  325   a - c  to the primary device  105 . Alternatively, the secondary devices  110 - 130  may occupy the same slot as used to transmit the polling response messages  315   a - c . It should be understood that the same slot means the same slot after the respective poll. For example, if the secondary device  110  transmitted polling response message  315   a  in slot R 1  after ranging poll  310 , the secondary device  110  will transmit time stamp response message  325   a  in slot T 1 . The timing response slots are indicated as T 1 , T 2  . . . T N , wherein N is the number of available slots. The time stamp response messages  325   a - c  may each include a time stamp. The primary device  105  may use the respective time stamps to derive a distance between the primary device  105  and each of the plurality of secondary devices  110 - 130 . 
     The primary device  105  may also transmit a message  330  comprising time stamps to the secondary devices  110 - 130 . The primary device  105  may report its time stamps to allow the secondary devices  110 - 130  to independently derive the distance between the devices. Thus, after message  330  is transmitted, the ranging round  350  is complete. 
       FIG. 4  shows a second exemplary timing diagram for a multicast ranging operation  400  according to various exemplary embodiments. The multicast ranging operation  400  will be described with reference to the network arrangement  100  of  FIG. 1 . Again, the timing diagram of  FIG. 4  will illustrate a single ranging round  450 , but multiple rounds are possible. 
     The primary device  105  may transmit a pre-poll message  405  carrying ranging configuration information to the secondary devices  110 - 130  via the UWB network. The transmission of the pre-poll message  405  may be substantially similar to the transmission of the pre-poll message  305 . 
     The primary device  105  may multicast a first ranging poll  410  to the secondary devices  110 - 130 . The first ranging poll  310  may be substantially similar to the first ranging poll  310 , with appropriate field adjustments to indicate multicast ranging, as will be described in further detail with respect to  FIG. 5 . 
     The secondary devices  110 - 130  may be scheduled to transmit polling response messages  415   a - c  in a polling response slot. The polling response slots are indicated as R 1 , R 2  . . . R N , wherein N is a number of available slots. The polling response slot for each secondary device  110 - 130  may be scheduled by the primary device  105  because the number and identities of the secondary devices are known to the primary device  105 . However, in another exemplary embodiment, the secondary devices  110 - 130  may contend for the polling response slots if no schedule is provided by the primary device  105 . 
     Similar to the broadcast ranging operation  300  described with respect to  FIG. 3 , receipt of the polling response messages  415   a - c  may be considered to complete the ranging round  450 . However, for substantially similar reasons as described above, a second ranging poll  420  may also be used. 
     The primary device  105  may multicast a second ranging poll  420  to the secondary devices  110 - 130  via the UWB network. The second ranging poll  420  may be substantially similar to the first ranging poll  410 , with appropriate modifications to the MAC IE  400  to indicate the expected response is a timestamp response. 
     The secondary devices  110 - 130  may be scheduled to send time stamp response messages  425   a - c  in a time stamp report slot by the primary device  105 . The time stamp report slot may be the same for a given secondary device as the poll response slot or may be a different slot. The time stamp report slots are indicated as T 1 , T 2  . . . T N , wherein N is the number of available slots. The time stamp response messages  425   a - c  each include a time stamp. The primary device  105  may use the respective time stamps to derive a distance between the primary device  105  and each of the plurality of secondary devices  110 - 130 . 
     The primary device  105  may also transmit a message  430  comprising time stamps to the secondary devices  110 - 130 . The primary device  105  may report its time stamps to allow the secondary devices  110 - 130  to independently derive the distance between the devices. Thus, after message  430  is sent, the ranging round  450  is complete. 
     As described above,  FIGS. 3 and 4  illustrate a single ranging round  350 ,  450 , respectively. The ranging rounds may be repeated as necessary. For example, there may be a second ranging round and a third ranging round after a first ranging round. The ranging rounds do not need to be contiguous, e.g., there may be time gaps between ranging rounds. The time gap may be indicated in the MAC IE  500 . With respect to the multicast ranging operation  400 , the manner of sending polling response messages  415   a - c , e.g., schedule-based or contention-based, may change from round to round. 
     In a further exemplary embodiment, the initial polling message may comprise two polling messages, wherein polling message P 1  may be used by a first subset of the secondary devices  110 - 130  and a polling message P 2  that may be used by a second subset, e.g. the remainder of the secondary devices  110 - 130 . The first and second subsets may be determined based on an ability of a secondary device to transmit time stamps in the polling response message. As described above, the primary device  105  and the secondary devices  110 - 130  may exchange information about ranging capabilities. For example, if a secondary device has the capability of sending timestamp information in a polling response message, the secondary device may treat the ranging poll similar to the ranging polls  310  and  410  and respond with a polling response message similar to polling response messages  315 ,  415 . On the other hand, if a secondary device does not have the capability of sending timestamp information in a polling response message, the secondary device may treat the ranging poll similar to the ranging polls  320  and  420  and respond with a timestamp response message similar to time stamp response message  325 ,  425 . 
       FIG. 5  shows an exemplary MAC IE  500  according to various exemplary embodiments described herein. The MAC IE  500  defines various MAC fields to support the broadcast/multicast ranging operations described herein. For example, the MAC IE  500  may indicate the ranging mode as one of the single node ranging mode, the multicast ranging mode, or the broadcast ranging mode. The MAC IE  500  may further indicate a number of ranging rounds, a duration of each ranging round, and a number of available poll response slots. The number of poll response slots may be configurable by the primary device  105 . For example, in the multicast mode where the primary device  105  is aware of the number of secondary devices  110 - 130 , the primary device  105  may set the number of response slots based on the number of secondary devices, e.g., 5 slots when there are 5 secondary devices. The MAC IE  500  may also include a counter showing the number of the current exchange round (e.g. 3 of 5). If the ranging rounds are non-continuous (e.g. there is a time gap between rounds), the MAC IE  500  may point to a timing of a next poll (or pre-poll). 
     If the ranging mode is the multicast ranging mode, the MAC IE  500  may specify whether the secondary devices  110 - 130  are scheduled for poll response slots or will contend for poll response slots. If the secondary devices  110 - 130  are scheduled, the MAC IE  500  may also specify the slot assignments for each of the secondary devices  110 - 130 . However, this specification may also be indicated as part of the upper layer protocols. If the ranging mode is broadcast ranging, the MAC IE  500  may specify a maximum number of attempts for each of the secondary devices  110 - 130  to contend for a response slot. 
     As described above, the secondary devices  110 - 130  may contend for response slots. Legacy channel contention typically uses energy detection and preamble detection to sense a transmission medium prior to attempting a transmission. When a device senses that the transmission medium is in use, it will back off for a random time before sensing the medium again and attempting the transmission. Energy detection is typically not useful for UWB networks because UWB signals are transmitted at a very low power over a large bandwidth. In addition, IEEE 802.15.4 specifies that different UWB packets may use different preambles. Thus, sensing the transmission medium by preamble detection may be inefficient, considering that every possible preamble would have to be tested by the device. 
     In the exemplary embodiments, the process by which the secondary devices  110 - 130  contend for the available polling response slots may be configurable. For example, a persistent channel use operation utilizing a free slot counter (FSC) may be used. The device may start the FSC at zero. A contending device may send a UWB packet over a channel using a specific slot. For each UWB packet that is transmitted successfully, the device may increase the FSC, e.g., by one increment. For each UWB packet that is transmitted unsuccessfully, the device may decrease the FSC, e.g., by one increment. The device may continue to use the channel/slot in this manner as long as the FSC remains at zero or above. However, if the FSC goes below zero, the device will deem the channel/slot to be busy and will move to a different channel/slot. 
     The increment by which the FSC is increased or decreased may be a function of a number of consecutive attempts. For example, the FSC may be decreased by one after a first failed transmission. If the next transmission attempt also fails, the FSC may be decreased by 2, etc. In this manner, a device that has established a good connection in a given channel/slot will continue to use the same channel/slot, and a device that attempts to use the same channel/slot will move to a different channel/slot. This exemplary contention procedure is not limited to the exemplary ranging operations but may be applied to any scenario where devices are contending for transmission resources. 
     As described above, the exemplary embodiments are described with reference to devices that may operate according to the IEEE 802.15.4 standard for UWB networks. Thus, the exemplary MAC IE  500  may be a variation of a MAC IE according to this protocol. However, if the UWB network is operating using a different protocol, a MAC IE having different fields may be used to convey the information that is used for the above described ranging operations. In addition, the information that is used for the ranging operation may be communicated between the devices using information elements (or other data elements) of other layers. 
     It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     It will be apparent to those skilled in the art that various modifications may be made to the present disclosure, without departing from the spirit or the scope of the exemplary embodiments. Thus, it is intended that the present disclosure cover modifications and variations of the exemplary embodiments provided they come within the scope of the appended claims and their equivalent.

Metadata:
Filing Date: 20191105
Publication Date: 20221108
Grant Date: 20221108
Priority Date: 20181109
Inventors: NAGUIB, AYMAN
BRUMLEY, ROBERT
GOLSHAN, Robert
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W12/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W56/0065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W74/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L12/1845", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W64/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S13/765", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L12/189", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W74/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S13/765", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 68501398