a locator device, comprising a wireless network interface; and

a plurality of tag devices, each comprising a wireless network interface;

wherein the wireless channel is segmented into a sequence of time slots, comprising a locator time slot allocated to transmissions by the locator device, a sync slot used to allow new tag devices to transmit packets and a plurality of tag slots, wherein each of the plurality of tag devices is assigned a specific tag slot by the locator device to transmit an AoA packet in response to a sync request packet transmitted by the tag device during a previous sync slot; and

wherein each of the tag devices transmits the AoA packet to the locator device during the specific tag slot assigned by the locator device.