Abstract: A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising combining tree search and Aloha methods to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision. A system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator in a wireless fashion, the respective wireless identification devices having a unique identification number, the interrogator being configured to employ tree search and Aloha techniques to determine the unique identification numbers of the different wireless identification devices so as to be able to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision by multiple wireless identification devices attempting to respond to the interrogator at the same time.

Abstract: Methods of processing wireless communication include providing at least one interrogator configured for transmitting and receiving wireless communication data. A plurality of identification devices are provided and are configured for receiving wireless communication data transmitted by the interrogator. Responsive to receiving such communication data, the devices are capable of generating and transmitting a reply back to the interrogator. Preferably, transmitted replies are delayed for different determinable amounts of time which enables the interrogator to detect multiple replies. In a preferred implementation, the wireless communication is radio frequency communication. In another preferred implementation, each device is capable of calculating its own delay utilizing a random value generator. Related system circuitry is described.

Abstract: A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method to establish communications without collision between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple levels representing subgroups of the multiple wireless identification devices, the number of devices in a subgroup in one level being half of the number of devices in the next higher level, the tree search method employing level skipping wherein at least one level of the tree is skipped.

Abstract: Method and apparatus for a base station or interrogator station to monitor the itinerary of one or more vehicles or other movable assets. Each vehicle or other movable object includes a satellite navigation receiver with circuitry for computing the geographic position of the object, and a memory for storing a history of positions computed at a number of different times during the itinerary of the object. Each movable object further includes a radio transceiver which transmits the stored position history to the base station.

Abstract: A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method to establish communications without collision between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple levels respectively representing subgroups of the multiple wireless identification devices, the method further comprising starting the tree search at a selectable level of the search tree.

Abstract: Methods of processing wireless communication include providing at least one interrogator configured for transmitting and receiving wireless communication data. A plurality of identification devices are provided and are configured for receiving wireless communication data transmitted by the interrogator. Responsive to receiving such communication data, the devices are capable of generating and transmitting a reply back to the interrogator. Preferably, transmitted replies are delayed for different determinable amounts of time which enables the interrogator to detect multiple replies. In a preferred implementation, the wireless communication is radio frequency communication. In another preferred implementation, each device is capable of calculating its own delay utilizing a random value generator. Related system circuitry is described.

Abstract: A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method to establish communications without collision between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple levels representing subgroups of the multiple wireless identification devices, the number of devices in a subgroup in one level being half of the number of devices in the next higher level, the tree search method employing level skipping wherein at least one level of the tree is skipped.

Abstract: A method of protecting data in a smart card from unauthorized access, the method comprising providing a housing defined by first and second housing portions; employing a volatile memory in the smart card for storing the data, and supporting the volatile memory from the first housing portion; providing a power supply in the housing, the power supply maintaining the data in the volatile memory while the power supply is connected to the volatile memory; and connecting the power supply to the volatile memory using a conductor supported by and movable with the second housing portion.

Abstract: A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method to attempt to identify individual ones of the multiple wireless identification devices so as to be able to perform communications, without collision, between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple nodes respectively representing subgroups of the multiple wireless identification devices, wherein the interrogator transmits a command at a node, requesting that devices within the subgroup represented by the node respond, wherein the interrogator determines if a collision occurs in response to the command and, if not, repeats the command at the same node.

Abstract: A wireless communications system comprising a first transponder having a plurality of selectable antennas, and having a stack including locations holding data representing antennas, the stack defining an order in which antennas will be used to attempt communication; a second transponder configured to communicate with the first transponder, wherein the first transponder uses an antenna defined by data in one location of the stack for communication with the second transponder, and, if successful communication with the second transponder is not established, the transponder uses an antenna defined by data in another if location of the stack.

Abstract: A method of protecting data in a smart card from unauthorized access, the method comprising providing a housing defined by first and second housing portions; employing a volatile memory in the smart card for storing the data, and supporting the volatile memory from the first housing portion; providing a power supply in the housing, the power supply maintaining the data in the volatile memory while the power supply is connected to the volatile memory; and connecting the power supply to the volatile memory using a conductor supported by and movable with the second housing portion.

Abstract: A wireless communications system comprising a first transponder having a plurality of selectable antennas, and having a stack including locations holding data representing antennas, the stack defining an order in which antennas will be used to attempt communication; a second transponder configured to communicate with the first transponder, wherein the first transponder uses an antenna defined by data in one location of the stack for communication with the second transponder, and, if successful communication with the second transponder is not established, the transponder uses an antenna defined by data in another location of the stack.