Watch pager system and communication protocol
First Claim
1. A method of sending data as a data signal from a transmitter to a plurality of remote receivers on a common transmission channel, comprising:
- time dividing the transmission channel into frames of a first duration, subdividing each frame into a plurality of subframes, and further subdividing each subframe into a plurality of time slots of a second duration, each frame repeating at periodic time intervals equal to said first duration;
numbering each subframe in the frame with a unique subframe number;
numbering a predetermined set of the time slots in each subframe, including numbering each time slot in said set with a unique number in a predetermined series of time slot numbers;
repeating said subframe and time slot numbers in each successive frame;
assigning each receiver a receiver address comprising one of the time slot numbers and one of the subframe numbers;
encoding the data for each receiver into a data packet of a predetermined length no greater than the duration of the time slots;
encoding in each packet a packet address including the number of a time slot during which the packet is to be transmitted;
transmitting a data signal comprising said packet during a time slot corresponding to the packet address; and
receiving the data signal and decoding the packet therefrom at a receiver that has a receiver address corresponding to the packet address.
7 Assignments
0 Petitions
Accused Products
Abstract
A wide area paging system is disclosed in which paging messages input to the system in one local area can be broadcast to a receiver in any other local area without necessarily broadcasting the message in all areas. A local area clearinghouse in each area stores resident subscriber data including current location and receiver serial number. This data is used to transfer messages over a data network to the correct clearinghouse. The system uses a TDM data protocol. The data is encoded and transmitted at a very high rate (e.g., 19,000 baud) in short packets (256 bits/13 milliseconds) via stereo FM sidebands. Receivers are assigned to receive sequentially numbered time slots matching a portion of their address. The addresses of intended receivers are included in the data packets. Battery-powered receivers are deactivated between packets and reactivated in accordance with the sequential time slot number scheme to receive an incoming packet. Messages longer than a packet are segmented and transmitted in two or more packets, linked together by data contained in the packets. A watch pager used in the system employs a wristband antenna which electromagnetically couples to the user'"'"'s body. The watch pager displays time, telephone numbers and icons representing common types of paging messages.
374 Citations
20 Claims
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1. A method of sending data as a data signal from a transmitter to a plurality of remote receivers on a common transmission channel, comprising:
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time dividing the transmission channel into frames of a first duration, subdividing each frame into a plurality of subframes, and further subdividing each subframe into a plurality of time slots of a second duration, each frame repeating at periodic time intervals equal to said first duration; numbering each subframe in the frame with a unique subframe number; numbering a predetermined set of the time slots in each subframe, including numbering each time slot in said set with a unique number in a predetermined series of time slot numbers; repeating said subframe and time slot numbers in each successive frame; assigning each receiver a receiver address comprising one of the time slot numbers and one of the subframe numbers; encoding the data for each receiver into a data packet of a predetermined length no greater than the duration of the time slots; encoding in each packet a packet address including the number of a time slot during which the packet is to be transmitted; transmitting a data signal comprising said packet during a time slot corresponding to the packet address; and receiving the data signal and decoding the packet therefrom at a receiver that has a receiver address corresponding to the packet address. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A communications system for transmitting data packets from a transmitter to a plurality of remote receivers, the system including a data protocol within each packet comprising:
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an address field for addressing a predetermined receiver, the field including a first field identifying a selected time slot within a predetermined number of time slots defining a subframe and a selected subframe within a predetermined number of subframes defining a periodically transmitted frame, the identified time slot and subframes specifying a time relative to a start of each frame during which a packet including the first field is transmitted; and a packet assembly field for assembling a message from data transmitted in more than one packet, the packet assembly field of a first packet indicating to a receiver a location of a following time slot during which a second packet intended for the receiver will be transmitted. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification