Spread spectrum cellular handoff apparatus and method
First Claim
1. An apparatus for controlling handoff of radio devices moving from one cell toward an adjacent cell of a spread-spectrum-CDMA-communications system, each adjacent cell having its own generic-chip-code signal embedded in a spread-spectrum-communications signal, comprising:
- a first base station for transmitting a first spread-spectrum-communications signal having a first generic-chip-code signal and message data spread-spectrum processed with a message-chip-code signal, embedded therein;
a second base station for transmitting a second spread-spectrum-communications signal having a second generic-chip-code signal embedded therein;
a radio device including,a personal-communications-network (PCN) antenna;
a first matched filter coupled to said PCN antenna and having an impulse response matched to the first generic-chip-code signal;
a first detector coupled to said first matched filter for detecting the first generic-chip-code signal embedded in the first spread-spectrum-communications signal communicated from said first base station and outputting a first detected signal;
a second matched filter coupled to said PCN antenna and having an impulse response matched to the second generic-chip-code signal;
a second detector coupled to said second matched filter for detecting the second generic-chip-code signal embedded in the second spread-spectrum-communications signal communicated from said second base station and outputting a second detected signal;
a comparator coupled to said first detector and to said second detector for generating a comparison signal by comparing the first detected signal with the second detected signal;
a receiver-message-chip-code generator for generating a replica of the message-chip-code signal;
a message mixer coupled to said receiver-message-chip-code generator and said PCN antenna, responsive to the replica of the message-chip-code signal, for despreading the spread-spectrum-communications signal as a modulated-data signal;
a message-bandpass filter coupled to said receiver-message-mixer device for filtering the modulated-data signal;
a message detector for demodulating the modulated-data signal as received data;
a synchronization circuit coupled to said comparator and responsive to the comparison signal being greater than a threshold, for synchronizing said receiver-message-chip-code generator to the first generic-chip-code signal for receiving the first spread-spectrum-communications signal from said first base station, and responsive to the comparison signal being less than the threshold for synchronizing said receiver-message-chip-code generator to the second generic-chip-code signal for receiving the second spread-spectrum-communications signal from said second base station; and
a control unit coupled to said first base station and said second base station and to many other base stations for switching the message data spread-spectrum processed with a message-chip-code signal, embedded in the first spread-spectrum-communications signal transmitted from said first base station, to the second spread-spectrum-communications signal transmitted from said second base station.
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Accused Products
Abstract
An apparatus for controlling handoff in a spread-spectrum-CDMA-communications system, of radio devices moving from a cell having a base station which transmits a first spread-spectrum-communications signal with a first generic-chip-code signal, toward a different cell having a base station for transmitting a second spread-spectrum-communications signal with a second generic-chip-code signal. A radio device includes a PCN antenna, a first matched filter having an impulse response matched to the first generic-chip-code signal and a first detector for detecting the first generic-chip-code signal embedded in the first spread-spectrum-communications signal. A second matched filter has an impulse response matched to the second generic-chip-code signal and a second detector detects the second generic-chip-code signal embedded in the second spread-spectrum-communications signal. A comparator generates a comparison signal by comparing the first detected signal with the second detected signal. A receiver-message-chip-code generator generates a replica of the message-chip-code signal and a message mixer, using a replica of the message-chip-code signal, despreads the spread-spectrum-communications signal as a modulated-data signal. A synchronization circuit, based on the comparison signal being greater than a threshold, synchronizes the receiver-message-chip-code generator to the first generic-chip-code signal for receiving the first spread-spectrum-communications signal, and in response to the comparison signal being less than the threshold, synchronizes the receiver-message-chip-code generator to the second generic-chip-code signal for receiving the second spread-spectrum-communications signal. A control unit switches transmitting the message data, spread-spectrum processed with a message-chip-code signal, embedded in the first spread-spectrum-communications signal from the first base station, to the second spread-spectrum-communications signal transmitted from the second base station.
231 Citations
16 Claims
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1. An apparatus for controlling handoff of radio devices moving from one cell toward an adjacent cell of a spread-spectrum-CDMA-communications system, each adjacent cell having its own generic-chip-code signal embedded in a spread-spectrum-communications signal, comprising:
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a first base station for transmitting a first spread-spectrum-communications signal having a first generic-chip-code signal and message data spread-spectrum processed with a message-chip-code signal, embedded therein; a second base station for transmitting a second spread-spectrum-communications signal having a second generic-chip-code signal embedded therein; a radio device including, a personal-communications-network (PCN) antenna; a first matched filter coupled to said PCN antenna and having an impulse response matched to the first generic-chip-code signal; a first detector coupled to said first matched filter for detecting the first generic-chip-code signal embedded in the first spread-spectrum-communications signal communicated from said first base station and outputting a first detected signal; a second matched filter coupled to said PCN antenna and having an impulse response matched to the second generic-chip-code signal; a second detector coupled to said second matched filter for detecting the second generic-chip-code signal embedded in the second spread-spectrum-communications signal communicated from said second base station and outputting a second detected signal; a comparator coupled to said first detector and to said second detector for generating a comparison signal by comparing the first detected signal with the second detected signal; a receiver-message-chip-code generator for generating a replica of the message-chip-code signal; a message mixer coupled to said receiver-message-chip-code generator and said PCN antenna, responsive to the replica of the message-chip-code signal, for despreading the spread-spectrum-communications signal as a modulated-data signal; a message-bandpass filter coupled to said receiver-message-mixer device for filtering the modulated-data signal; a message detector for demodulating the modulated-data signal as received data; a synchronization circuit coupled to said comparator and responsive to the comparison signal being greater than a threshold, for synchronizing said receiver-message-chip-code generator to the first generic-chip-code signal for receiving the first spread-spectrum-communications signal from said first base station, and responsive to the comparison signal being less than the threshold for synchronizing said receiver-message-chip-code generator to the second generic-chip-code signal for receiving the second spread-spectrum-communications signal from said second base station; and a control unit coupled to said first base station and said second base station and to many other base stations for switching the message data spread-spectrum processed with a message-chip-code signal, embedded in the first spread-spectrum-communications signal transmitted from said first base station, to the second spread-spectrum-communications signal transmitted from said second base station.
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2. An apparatus for controlling handoff of radio devices moving from one cell toward an adjacent cell of a spread-spectrum-CDMA-communications system, each adjacent cell having its own generic-chip-code signal embedded in a spread-spectrum-communications signal, comprising:
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a first base station for transmitting a first spread-spectrum-communications signal having a first generic-chip-code signal embedded therein; a second base station for transmitting a second spread-spectrum-communications signal having a second generic-chip-code signal embedded therein; a radio device including, a personal-communications-network (PCN) antenna; first generic-detection means coupled to said PCN antenna and including first generic-spread-spectrum-processing means, for detecting the first generic-chip-code signal embedded in the first spread-spectrum-communications signal communicated from said first base station and outputting a first detected signal; second generic-detection means coupled to said PCN antenna and including second generic-spread-spectrum-processing means, for detecting the second generic-chip-code signal embedded in the second spread-spectrum-communications signal communicated from said second base station and outputting a second detected signal; comparator means for generating a comparison signal by comparing the first detected signal with the second detected signal; message-spread-spectrum-processing means coupled to said PCN antenna for despreading the spread-spectrum-communications signal as a modulated-data signal; message-detection means for demodulating the modulated-data signal as received data; synchronizing means responsive to the comparison signal being greater than a threshold, for synchronizing said message-spread-spectrum-processing means and said detection means to the first generic-chip-code signal for receiving the first spread-spectrum-communications signal transmitted from said first base station, and responsive to the comparison signal being less than the threshold for synchronizing said message-spread-spectrum-processing means and said detection means to the second generic-chip-code signal for receiving the second spread-spectrum-communications signal transmitted from said second base station; and control means for switching the message data spread-spectrum processed with a message-chip-code signal embedded in the first spread-spectrum-communications signal transmitted from said first base station, to the second spread-spectrum-communications signal transmitted from said second base station. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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9. An apparatus for controlling handoff in a spread-spectrum-CDMA-communications system, a radio device moving from a first cell having a first base station for transmitting a first spread-spectrum-communications signal with a first generic-chip-code signal embedded therein, toward a second cell having a second base station for transmitting a second spread-spectrum-communications signal with a second generic-chip-code signal embedded therein, said spread-spectrum-CDMA-communications system having a control unit for switching message data, spread-spectrum processed with a message-chip-code signal embedded in the first spread-spectrum-communications signal transmitted from said first base station, to the second spread-spectrum-communications signal transmitted from said second base station, said apparatus comprising:
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a personal-communications-network (PCN) antenna; first generic-detection means coupled to said PCN antenna and including first generic-spread-spectrum-processing means, for detecting the first generic-chip-code signal embedded in the first spread-spectrum-communications signal communicated from said first base station and outputting a first detected signal; second generic-detection means coupled to said PCN antenna and including second generic-spread-spectrum-processing means, for detecting the second generic-chip-code signal embedded in the second spread-spectrum-communications signal communicated from said second base station and outputting a second detected signal; comparator means for generating a comparison signal by comparing the first detected signal with the second detected signal; message-spread-spectrum-processing means coupled to said PCN antenna for despreading the spread-spectrum-communications signal as a modulated-data signal; and synchronizing means responsive to the comparison signal being greater than a threshold, for synchronizing said message-spread-spectrum-processing means to the first generic-chip-code signal for processing the first spread-spectrum-communications signal transmitted from said first base station, and responsive to the comparison signal being less than the threshold for synchronizing said message-spread-spectrum-processing means and said detection means to the second generic-chip-code signal for receiving the second spread-spectrum-communications signal transmitted from said second base station. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for controlling handoff in a spread-spectrum-CDMA-communications system, of radio devices moving from a first cell having a first base station for transmitting a first spread-spectrum-communications signal with a first generic-chip-code signal embedded therein, toward a second cell having a second base station for transmitting a second spread-spectrum-communications signal with a second generic-chip-code signal embedded therein, said spread-spectrum-CDMA-communications system having a control unit for switching message data, spread-spectrum processed with a message-chip-code signal embedded in the first spread-spectrum-communications signal transmitted from said first base station, to the second spread-spectrum-communications signal transmitted from said second base station, said method comprising the steps of:
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detecting the first generic-chip-code signal embedded in the first spread-spectrum-communications signal communicated from said first base station and outputting a first detected signal; detecting the second generic-chip-code signal embedded in the second spread-spectrum-communications signal communicated from said second base station and outputting a second detected signal; generating a comparison signal by comparing the first detected signal with the second detected signal; despreading, using message-spread-spectrum-processing means, the spread-spectrum-communications signal as a modulated-data signal; synchronizing, in response to the comparison signal being greater than a threshold, said message-spread-spectrum-processing means to the first generic-chip-code signal for processing the first spread-spectrum-communications signal transmitted from said first base station; and synchronizing, in response to the comparison signal being less than the threshold, said message-spread-spectrum-processing means to the second generic-chip-code signal for receiving the second spread-spectrum-communications signal transmitted from said second base station.
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Specification