Two-way paging system and apparatus
First Claim
1. A paging network having at least one paging transmitter and receiver site for transmitting paging messages and for receiving acknowledgments comprising:
- a timing control unit for timing said paging transmissions and for activating receive processing channels;
a plurality of directive antennas coupled to associated receive signal processing means for receiving signals from respective antennas and converting said signals to corresponding complex numerical samples at times determined by said timing control unit;
a memory for storing said complex numerical samples; and
digital beamforming and processing means for processing said complex numerical samples from each of a first plurality of antennas in a plurality of ways corresponding to different possible directions and times of arrival of said acknowledgments from a pluraliyt of said pagers in order to improve probability of detection of said acknowledgments.
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Abstract
Paging systems typically include a network of ground stations or orbiting satellites equipped with transmitters and antennas for transmitting paging messages to small, battery-operated paging receivers that are worn about the person, known as pagers. Conventional pagers are receive-only devices and the network receives no confirmation that paging has been successful. The present invention includes the provision of two-way pagers that contain a transmitter for transmitting an acknowledgment confirming reception of a paging message, and a network of receiving stations able to receive said acknowledgments. The network makes use of advanced phased-array antenna signal processing techniques to render the return link operable with much less transmitter power in the portable unit than employed by the base station.
63 Citations
13 Claims
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1. A paging network having at least one paging transmitter and receiver site for transmitting paging messages and for receiving acknowledgments comprising:
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a timing control unit for timing said paging transmissions and for activating receive processing channels; a plurality of directive antennas coupled to associated receive signal processing means for receiving signals from respective antennas and converting said signals to corresponding complex numerical samples at times determined by said timing control unit; a memory for storing said complex numerical samples; and digital beamforming and processing means for processing said complex numerical samples from each of a first plurality of antennas in a plurality of ways corresponding to different possible directions and times of arrival of said acknowledgments from a pluraliyt of said pagers in order to improve probability of detection of said acknowledgments. - View Dependent Claims (2)
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3. A paging network having at least one paging transmitter and receiver site for transmitting paging messages and for receiving acknowledgments, comprising:
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timing control means for timing said paging transmissions and for activating receiver circuitry; plural antenna means for favoring reception of signals from at least one of different directions and different polarizations; wherein said receiver circuitry is coupled to each of said plural antenna means for filtering, amplifying and converting respective received signals to corresponding complex numerical sample sequences under control of said timing control means; memory means for storing said complex numerical sample sequences; digital beamforming means having a complex coefficient matrix for processing said stored complex numerical sample sequences to produce combined sequences each corresponding to reception from different directions; correlation means for correlating each of said combined sequences with a predetermined signal pattern to produce correlation values for different shifts of each of said combined sequences corresponding to different time delays of a received signal; and comparison means for comparing each of said correlation values with others and with a threshold value in order to decide if an acknowledgment was detected from a particular direction and with a particular time delay and for producing a corresponding detection indication. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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10. A two-way paging network capable of transmitting short messages to and receiving short messages from portable paging units, comprising:
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plural antennas connected to respective receive channel processing units which convert respective received signal samples to corresponding sequences of binary numbers related to sample phase and the logarithm of sample amplitude; memory means for storing said phase and logamplitude-related numbers and a coefficient matrix; arithmetic unit means for combining said stored phase and logamplitude-related numbers with said stored coefficients to produce sequences of combined complex numbers having a real and an imaginary part, each sequence representing an enhanced signal reception from a particular direction; and correlation means for correlating each of said combined sequences with a predetermined signal pattern and producing a signal detection and direction of arrival indication. - View Dependent Claims (11)
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12. A two-way paging network capable of transmitting short messages to and receiving short messages from portable paging units, comprising:
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plural antennas connected to respective receive channel processing units which convert respective received signal samples to corresponding sequences of complex numbers; memory means for storing said complex numbers and a complex coefficient matrix; arithmetic unit means for combining said stored complex numbers with said stored complex coefficient matrix in order to produce combined sequences each representing signal reception from a particular direction; correlation means for correlating each of said combined sequences with predetermined signal patterns and producing a signal detection and direction of arrival indication; and decoding means which is activated if said detection indication has a first value to further process selected ones of said combined sequences as indicated by said direction of arrival indication in order to decode a short message from a portable paging unit. - View Dependent Claims (13)
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Specification