Network supporting roaming, sleeping terminals
First Claim
1. An improved apparatus for collecting, transmitting, and processing data stored in a code such as a bar code, said apparatus including a portable code reader with processing and transmitting units for radiating information in the form of electromagnetic waves, a stationary receiver physically separate from the code reader, and a data processor coupled to the stationary receiver, wherein the improvement comprises:
- a network controller member having a multiplicity of communication ports thereon, said network controller member intercommunicative with said data processor at one of said communication ports;
said network controller member intercommunicative with said stationary receiver at another of said communication ports; and
said network controller member selectively operable with said data processor at one or more communication rates.
1 Assignment
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Accused Products
Abstract
Improved apparatus for a radio communication system having a multiplicity of mobile transceiver units selectively in communication with a plurality of base transceiver units which, in turn, communicate with one or more host computers for storage and manipulation of data collected by bar code scanners or other collection means associated with the mobile transceiver units. A network controller and an adapter which has a simulcast and sequential mode provide selective interface between host computers and base transceivers. A scheme for routing data through the communication system is also disclosed wherein the intermediate base stations are organized into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Additionally, redundant network and communication protocol is disclosed wherein the network utilizes a polling communication protocol which, under heavy loaded conditions, requires that a roaming terminal wishing to initiate communication must first determine that the channel is truly clear by listing for an entire interpoll gap time. In a further embodiment, a criterion used by the roaming terminals for attaching to a given base station reduces conflicts in the overlapping RF regions of adjacent base stations.
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Citations
37 Claims
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1. An improved apparatus for collecting, transmitting, and processing data stored in a code such as a bar code, said apparatus including a portable code reader with processing and transmitting units for radiating information in the form of electromagnetic waves, a stationary receiver physically separate from the code reader, and a data processor coupled to the stationary receiver, wherein the improvement comprises:
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a network controller member having a multiplicity of communication ports thereon, said network controller member intercommunicative with said data processor at one of said communication ports;
said network controller member intercommunicative with said stationary receiver at another of said communication ports; and
said network controller member selectively operable with said data processor at one or more communication rates. - View Dependent Claims (2, 3, 4, 5)
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6. In a data communication system having a plurality of mobile transceiver units communicative with a plurality of base transceiver units,
a network controller intercommunicative between the base transceiver units and one or more host computers for data interchange therebetween.
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7. A data communication system having a plurality of mobile transceiver units selectively communicative with a plurality of base transceiver units, comprising:
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a network controller intercommunicative between the base transceiver units and one or more host computers for data interchange therebetween;
an adapter coupled to the network controller and intercommunicative between said controller and said plurality of base transceiver units; and
said adapter providing coupling between said network controller and said base transceiver units simultaneously.
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8. A radio frequency data communication system for transmission of data collected by a multiplicity of remote terminals to one or more base stations, comprising:
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the multiplicity of remote terminals selectively communicative with said one or more base stations, each of said remote terminals selectively operable in response to transmission from one of said base stations; and
each of said remote terminals independently cycling from a dormant status to an active status over predetermined time intervals when no transmission from a base station is directed to such remote terminal.
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9. A radio frequency data communication system for transmission of data collected by a multiplicity of roaming terminals each having a radio transmitter to one or more base stations, comprising:
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the multiplicity of roaming terminals selectively communicative with said one or more base stations, each of said roaming terminals selectively operable in response to transmission from one of said base stations; and
each of said roaming terminals maintaining the radio transceiver energized by battery power for a selected time interval, and after such selected time interval or after completion of a transmission occurring within such time interval, periodically turning the radio transceiver off for substantial time intervals to conserve battery power.
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10. In a data communication system having a host computer, a plurality of intermediate bridging stations, and a plurality of mobile transceiver units, all communicative with a base station, a local area network comprising:
said plurality of intermediate bridging stations organized into an optimal spanning tree with said base station at the root. - View Dependent Claims (11, 12, 13)
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14. A method of routing information in a data communication system having a host computer, a plurality of intermediate bridges, and a plurality of mobile transceiver units, all communicative with a base station, comprising the following steps:
organizing said data communication system into an optimal spanning tree with said base station at the root. - View Dependent Claims (15, 16)
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17. A method of routing information in a data communication system having a host computer, a plurality of intermediate bridges, and a plurality of mobile transceiver units, all communicative with a base station, comprising the following steps:
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(a) organizing said data communication system into an optimal spanning three with said base station at the root; and
(b) said step of organizing further comprising the step of said attached bridges using a backward learning technique to learn the correct path to route data communication between said host computer and said mobile transceiver units.
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18. A method of beginning a data exchange over and RF communication link between a polling device and a sending device wherein the polling device has an interpoll gap time, comprising the steps of:
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(a) identifying by the sending device that the RF communication link is clear throughout a period which is at least as long as the maximum possible interpoll gap time; and
(b) transmitting a request for poll frame by the sending device.
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19. A method used by a remote terminal having an RF range for selectively attaching itself to one of a plurality of RF base stations each of which has an associated cost, a preset priority and a preset number, comprising the steps of:
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(a) receiving by the remote terminal messages indicative of the signal strength of each of the base stations within RF range;
(b) discarding all messages with signal strengths below a predetermined minimum threshold level; and
(c) attaching itself to one of the plurality base station based on the cost, the signal strength of the messages, the preset priority and the preset number.
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20. A method for selecting and redundantly replacing a root device when it breaks down from among a plurality of potentially root devices, each of said potential root device having a single, assigned preset number, comprising the steps of:
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initially selecting the potential root device by identifying the lowest assigned preset number of the plurality of potential root devices; and
repeating said step of selecting without considering the preset number of the current selected root device, whenever the currently selected root device breaks down.
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21. A method used by a remote terminal for gathering and transmitting data to one or more base stations, said method comprising the steps of:
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when not gathering data, operating at a lower system clock rate so as to minimize digital noise in transmission to and reception from one or more of the base stations; and
when gathering data, operating at a higher system clock rate to increase data input.
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22. A method used by a base station having both a non-directional and a programmable, directional antenna system in a radio frequency communication system having a plurality of base stations and roaming terminals, said method comprising the steps of:
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(a) transmitting using a non-directional antenna system when communicating with one of a plurality of roaming terminals; and
(b) programmably adjusting the transmission power and direction of a directional antenna system and transmitting using the directional antenna system when communicating with another of the plurality of base stations.
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23. In a data communication system having a plurality of mobile transceiver units communicative with a plurality of base transceiver units,
a network controller intercommunicative between the base transceiver units and one or more host computers for data interchange therebetween, and having port means providing interface at a relatively low data rate and at a relatively high data rate.
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32. An improved apparatus for collecting, transmitting, and processing data stored in a code such as a bar code, said apparatus including a portable code reader with processing and transmitting units for radiating information in the form of electromagnetic waves, a stationary receiver physically separated from the code reader, and a data processor coupled to the stationary receiver, wherein the improvement comprises:
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a network controller member having a multiplicity of communication ports thereon;
said network controller member intercommunicative with said data processor at one of said communication ports;
said network controller member intercommunicative with said stationary receiver at another of said communication ports; and
said network controller member selectively operable with said data processor at one or more communication rates. - View Dependent Claims (33, 34, 35, 36, 37)
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Specification