Many to many ranging techniques
AssigneeApple Inc.
InventorsYagil Burowski, Subash Marri Sridhar, Ayman Naguib, Robert Golshan
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Abstract
A mobile device can include ranging circuitry to determine distance to another mobile device. Ranging between multiple mobile devices can present challenges due to clock drift between the devices resulting in missed messages due to collisions between ranging messages. Techniques can be implemented to reduce the number of collisions by designating time slots for ranging sessions based on timing from a coordinator mobile device. Alternative techniques allow for splitting up channels at different time amount different pairs of devices. The ranging techniques can be used to share information between devices with a predefined distance for applications such as augmented reality.
Claims22
A method performed by a coordinator mobile device of N mobile devices that includes other mobile devices, N being an integer of three or more, the method comprising:
- detecting the other mobile devices using a first wireless protocol;
- accessing an active participant list in a memory of the coordinator mobile device, the active participant list comprising a plurality of unique identifiers assigned to each of the N mobile devices;
- transmitting the active participant list to the other mobile devices using the first wireless protocol;
- determining an order for a plurality of ranging operations between the N mobile devices by generating a table for a ranging session comprising multiple ranging operations using the plurality of unique identifiers in the active participant list, the table having one or more rows, each corresponding to a different time period, and one or more columns corresponding to one or more communication channels, wherein each entry of the table specifies a pair of mobile devices designated to perform a ranging operation during a particular time period using a particular communication channel;
- and
- for each of the other mobile devices:
- performing a ranging operation at the particular time period using the particular communication channel designated in the table, wherein each of the other mobile devices performs respective ranging operations based on timing from the coordinator mobile device and using a respective table specifying the order for the plurality of ranging operations.
A non-transitory computer-readable medium storing a plurality of instructions that, when executed by one or more processors of a coordinator mobile device of N mobile devices that includes other mobile devices, N being an integer of three or more, cause the one or more processors to perform operations comprising:
- detecting the other mobile devices using a first wireless protocol;
- accessing an active participant list in a memory of the coordinator mobile device, the active participant list comprising a plurality of unique identifiers assigned to each of the N mobile devices;
- transmitting the active participant list to the other mobile devices using the first wireless protocol;
- determining an order for a plurality of ranging operations between the N mobile devices by generating a table for a ranging session comprising multiple ranging operations using the plurality of unique identifiers in the active participant list, the table having one or more rows, each corresponding to a different time period, and one or more columns corresponding to one or more communication channels, wherein each entry of the table specifies a pair of mobile devices designated to perform a ranging operation during a particular time period using a particular communication channel;
- and
- for each of the other mobile devices:
- performing a ranging operation at the particular time period using the particular communication channel designated in the table, wherein each of the other mobile devices performs respective ranging operations based on timing from the coordinator mobile device and using a respective table specifying the order for the plurality of ranging operations.
A method performed by a first mobile device of N mobile devices that includes other mobile devices, N being an integer of three or more, the method comprising:
- receiving, using a first wireless protocol, greeting messages from the other mobile devices, wherein the greeting messages containing unique identifiers for each of the N mobile devices;
- accessing, in a memory, a specified ordering of the N mobile devices, the specified ordering delineating an order for ranging operations between the N mobile devices, wherein the specified ordering is determined using the unique identifiers of the N mobile devices;
- transmitting a start message at a start time, the start message comprising a start command to begin a ranging session comprising a plurality of ranging operations;
- performing a first ranging operation with a second mobile device of the N mobile devices at a first predetermined time after the start time, the first predetermined time determined in accordance with the specified ordering;
- and
- performing a second ranging operation with a third mobile device of the N mobile devices at a second predetermined time after the start time, the second predetermined time determined in accordance with the specified ordering.
Dependencies are inferred from the claim text.