Methods and systems for deriving seed position of a subscriber station in support of unassisted GPS-type position determination in a wireless communication system
First Claim
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1. A method of deriving a seed position of a subscriber station in a wireless communication system, comprising:
- receiving an overhead message from the wireless communication system; and
deriving the seed position of the subscriber station from a parameter in the overhead message comprisingderiving a first position estimate of the subscriber station from the parameter;
attempting to derive a second position estimate of the subscriber station;
setting the seed position of the subscriber station to the first position estimate if the second position estimate is unavailable;
setting the seed position of the subscriber station to the first position estimate if the second position estimate has a higher position uncertainty then the first position estimate; and
setting the seed position of the subscriber station to the second position estimate if the second position estimate has a lower position uncertainty than the first position estimate.
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Abstract
In a method and system for deriving a seed position of a subscriber station in a wireless communications system in supporting unassisted GPS-type position determination is provided, the subscriber station receives overhead messages from the wireless communications system, and derives the seed position from the parameter values. The subscriber station may use a data structure in its memory and map possible parameter values to corresponding positions that may serve as the seed positions.
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Citations
28 Claims
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1. A method of deriving a seed position of a subscriber station in a wireless communication system, comprising:
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receiving an overhead message from the wireless communication system; and deriving the seed position of the subscriber station from a parameter in the overhead message comprising deriving a first position estimate of the subscriber station from the parameter; attempting to derive a second position estimate of the subscriber station; setting the seed position of the subscriber station to the first position estimate if the second position estimate is unavailable; setting the seed position of the subscriber station to the first position estimate if the second position estimate has a higher position uncertainty then the first position estimate; and setting the seed position of the subscriber station to the second position estimate if the second position estimate has a lower position uncertainty than the first position estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a subscriber station having a position in a wireless communications system, a method of updating one or more data structures associating possible values of one or more overhead message parameters with corresponding positions, the method comprising:
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obtaining values of one or more parameters from one or more overhead messages received by the subscriber station from a wireless communications system; mapping the one or more parameter values to a corresponding position by accessing the one or more data structures; setting a seed position of the subscriber station to the corresponding position, wherein the act of setting the seed position comprises; deriving a first position estimate of the subscriber station from the one or more parameter values; attempting to derive a second position estimate of the subscriber station; setting the seed position of the subscriber station to the first position estimate if the second position estimate is unavailable; setting the seed position of the subscriber station to the first position estimate if the second position estimate has a higher position uncertainty then the first position estimate; and setting the seed position of the subscriber station to the second position estimate if the second position estimate has a lower position uncertainty than the first position estimate; deriving a fix of the position of the subscriber station from one or more satellite transmissions originating from a GPS-type position determination system, including searching for one or more of such transmissions responsive to the seed position; determining whether an update condition is present responsive to the fix of the subscriber station'"'"'s position; and updating the one or more data structures if an update condition is present. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. In a subscriber station having a position in a wireless communications system, a method of updating one or more data structures having a plurality of entries associating possible values of one or more parameters, obtainable from one or more overhead messages communicated by a wireless communications system, with corresponding positions, the method comprising:
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obtaining values of one or more parameter values from one or more overhead messages received by the subscriber station from a wireless communications system; accessing the one or more data structures to determine if one or more entries are present associating the one or more parameter values with a corresponding position; setting a seed position comprising; deriving a first position estimate of the subscriber station from the one or more parameter values; attempting to derive a second position estimate of the subscriber station; setting the seed position of the subscriber station to the first position estimate if the second position estimate is unavailable; setting the seed position of the subscriber station to the first position estimate if the second position estimate has a higher position uncertainty then the first position estimate; and setting the seed position of the subscriber station to the second position estimate if the second position estimate has a lower position uncertainty than the first position estimate; and updating the one or more data structures if said one or more entries are not present in the one or more data structures. - View Dependent Claims (19, 20)
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21. A subscriber station having a position in a wireless communications system, the subscriber station comprising:
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a memory storing a data structure associating possible parameter values obtainable by the subscriber station from at least one overhead messages communicated by the wireless communications system, with corresponding positions and position uncertainty values; and at least one processor configured to; (1) obtain parameter values from the at least one overhead message; (2) access the data structure to map the parameter values to a corresponding position; and (3) derive a seed position of the subscriber station responsive to the access thereby to (3a) derive a first position estimate of the subscriber station from the parameter values; (3b) attempt to derive a second position estimate of the subscriber station; (3c) set the seed position of the subscriber station to the first position estimate if the second position estimate is unavailable; (3d) set the seed position of the subscriber station to the first position estimate if the second position estimate has a higher position uncertainty then the first position estimate; and (3e) set the seed position of the subscriber station to the second position estimate if the second position estimate has a lower position uncertainty than the first position estimate. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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Specification