CDMA communications and geolocation system and method
First Claim
1. A spread-spectrum communications and geolocation method for communicating message data, comprising the steps of:
- generating, at a base station, a base-generic-chip-code signal;
spread-spectrum processing the message data with a message-chip-code signal as a spread-spectrum-processed-message data;
combining the base-generic-chip-code signal with the spread-spectrum-processed-message data, thereby generating a base-code-division-multiple-access (CDMA) signal;
transmitting, using radio waves traversing free space, the base-CDMA signal from a transmitter over a communications channel;
detecting, from the communications channel at a remote unit, the base-generic-chip-code signal embedded in the base-CDMA signal;
recovering, using the detected-base-generic-chip-code signal, the message data embedded in the base-CDMA signal;
relaying the detected-base-generic-chip-code signal as a remote-generic-chip-code signal;
spread-spectrum processing remote-message data with a remote-chip-code signal as a spread-spectrum-processed-remote-message data;
combining the spread-spectrum-processed-remote-message data with the remote-generic-chip-code signal as a remote-CDMA signal;
transmitting the remote-CDMA signal over the communications channel to the base station;
detecting, at the base station, the remote-generic-chip-code signal embedded in the remote-CDMA signal; and
recovering, using the detected-remote-generic-chip-code signal, the remote-message data embedded in the remote-CDMA signal.
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Accused Products
Abstract
A spread-spectrum CDMA communications system for locating remote units, and for communicating message data between a plurality of remote units and a base station. The spread-spectrum CDMA communications system includes a plurality of base stations and a plurality of remote units. A base station has a spread-spectrum modulator for spread-spectrum processing the message data, and a transmitter for transmitting the spread-spectrum processed-message data, combined with a generic-chip-code signal, from the base station to a remote unit. The base station also has an antenna, and spread-spectrum detectors for recovering message-data communicated from the remote units. A remote unit has an antenna, and a detector coupled to the antenna for recovering data communicated from the base station. The detector includes a spread spectrum demodulator. Also, the remote unit has a device for converting the format of the data into a form suitable for communicating over radio waves, a spread spectrum modulator and a transmitter. The base station has a range circuit, which comparers the generic-chip-code signal generated at the base station with the generic-chip-code signal received from the remote unit, for determining a range between the remote unit and the base station.
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Citations
7 Claims
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1. A spread-spectrum communications and geolocation method for communicating message data, comprising the steps of:
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generating, at a base station, a base-generic-chip-code signal; spread-spectrum processing the message data with a message-chip-code signal as a spread-spectrum-processed-message data; combining the base-generic-chip-code signal with the spread-spectrum-processed-message data, thereby generating a base-code-division-multiple-access (CDMA) signal; transmitting, using radio waves traversing free space, the base-CDMA signal from a transmitter over a communications channel; detecting, from the communications channel at a remote unit, the base-generic-chip-code signal embedded in the base-CDMA signal; recovering, using the detected-base-generic-chip-code signal, the message data embedded in the base-CDMA signal; relaying the detected-base-generic-chip-code signal as a remote-generic-chip-code signal; spread-spectrum processing remote-message data with a remote-chip-code signal as a spread-spectrum-processed-remote-message data; combining the spread-spectrum-processed-remote-message data with the remote-generic-chip-code signal as a remote-CDMA signal; transmitting the remote-CDMA signal over the communications channel to the base station; detecting, at the base station, the remote-generic-chip-code signal embedded in the remote-CDMA signal; and recovering, using the detected-remote-generic-chip-code signal, the remote-message data embedded in the remote-CDMA signal. - View Dependent Claims (3, 4, 5)
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2. A spread-spectrum communications and geolocation method for communicating message data, comprising the steps of:
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generating, at a base station, a base-generic-chip-code signal; spread-spectrum processing the message data with a message-chip-code signal as a spread-spectrum-processed-message data; combining the base-generic-chip-code signal with the spread-spectrum-processed-message data, thereby generating a base-code-division-multiple-access (CDMA) signal; transmitting, using radio waves traversing free space, the base-CDMA signal from a transmitter over a communications channel; detecting, from the communications channel at a remote unit, the base-generic-chip-code signal embedded in the base-CDMA signal; recovering, using the detected-base-generic-chip-code signal, the message data embedded in the base-CDMA signal; generating a remote-generic-chip-code signal; setting a timing of the remote-generic-chip-code signal using the detected-base-generic-chip-code signal; spread-spectrum processing remote-message data with a remote-chip-code signal as a spread-spectrum-processed-remote-message data; combining the spread-spectrum-processed-remote-message data with the remote-generic-chip-code signal as a remote-CDMA signal; transmitting the remote-CDMA signal over the communications channel to the base station; detecting, at the base station, the remote-generic-chip-code signal embedded in the remote-CDMA signal; and recovering, using the detected-remote-generic-chip-code signal, the remote-message data embedded in the remote-CDMA signal.
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6. A spread-spectrum communications and geolocation method for communicating message data, comprising the steps of:
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generating, at a remote unit, a remote-generic-chip-code signal; spread-spectrum processing the message data with a message-chip-code signal as a spread-spectrum-processed-message data; combining the remote-generic-chip-code signal with the spread-spectrum-processed-message data, thereby generating a remote-code-division-multiple-access (CDMA) signal; transmitting, using radio waves traversing free space, the remote-CDMA signal from a transmitter over a communications channel; detecting, from the communications channel at a base station, the remote-generic-chip-code signal embedded in the remote-CDMA signal; recovering, using the detected-remote-generic-chip-code signal, the message data embedded in the remote-CDMA signal; generating a base-generic-chip-code signal; setting a timing of the base-generic-chip-code signal using the detected-remote-generic-chip-code signal; spread-spectrum processing base-message data with a base-chip-code signal; combining the spread-spectrum-processed-base-message data with the base-generic-chip-code signal as a base-CDMA signal; transmitting the base-CDMA signal over the communications channel to the remote unit; detecting, at the remote unit, the base-generic-chip-code signal embedded in the base-CDMA signal; and recovering, using the detected-base-generic-chip-code signal, the base-message data embedded in the base-CDMA signal. - View Dependent Claims (7)
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Specification