Mobile device positioning in dynamic groupings of communication devices

摘要

A wi-fi based mobile positioning system determines mobile device positioning by count stamped packets communicated between the mobile device and access points according to a standard wifi protocol. Ad-hoc groups of wifi network nodes are formed and then broken with a mobile device as that mobile devices moves relative to fixed nodes, such as access points. Within an ad-hoc group, the nodes count stamp packets by latching a local counter within each node. Count-stamps are collected and used to generate ranges for a mobile device relative to nodes in an ad hoc group. A positioning services determines the position of the mobile device from the ranges.

主权项

1. A wifi based mobile device positioning system, the system comprising:
an access point device for receiving receive messages transmitted from a plurality of other communication devices, each receive message including a transmit count stamp corresponding to a remote counter value at a transmission of the receive message from a corresponding other communication device, wherein the access point is further operable to generate a receive count stamp for each receive message corresponding to a local counter value at receipt of a receive message from the other communication devices and for messages received from a mobile communication device; a node in communication with the access point, the node including a processor programmed to dynamically associate and disassociate the mobile communication device with a plurality of sub-groups of the plurality of other communication devices, based at least in part on receiving receive messages from a predetermined number of other communication devices for each sub-group; and a programmed processor executing to generate range estimates between the mobile communication device and other communication devices in the sub-group currently associated with the mobile communication device, the range estimates based on a combination of the transmit count stamps and the receive count stamps; and wherein at least one of the range estimates is a mobile device range estimate between the mobile device and a second communication device that the mobile communication device is newly associated with in one of the sub-groups, and the mobile device range estimate is computed as a function of count stamps previously communicated between the mobile device and other communication devices in the plurality of sub-groups.