Method and apparatus for locating a wireless user
First Claim
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1. A method for use in a subscriber unit, the method comprising:
- receiving, at the subscriber unit, at a first time of arrival, a first signal from a first antenna;
receiving, at the subscriber unit, at a second time of arrival, a second signal from a second antenna;
determining, at the subscriber unit, a difference between the first time of arrival of the first signal from the first antenna and the second time of arrival of the second signal from the second antenna; and
transmitting, by the subscriber unit, to the first antenna or the second antenna, a third signal carrying information indicating the determined difference between the first time of arrival of the first signal from the first antenna and the second time of arrival of the second signal from the second antenna, wherein the third signal is spread coded.
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Abstract
A plurality of antennas transmit a first spread spectrum signal having an associated code. The first spread spectrum signal is received at the wireless user. For each received first spread spectrum signal, a second spread spectrum signal is transmitted having an associated code having a same phase as that received first spread spectrum signal. The second spread spectrum signals are received at the plurality of antennas. A distance measurement is determined between each antenna and the wireless user based on in part a received timing of the second signals. The wireless user'"'"'s location is determined based on in part the distance determinations.
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Citations
25 Claims
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1. A method for use in a subscriber unit, the method comprising:
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receiving, at the subscriber unit, at a first time of arrival, a first signal from a first antenna; receiving, at the subscriber unit, at a second time of arrival, a second signal from a second antenna; determining, at the subscriber unit, a difference between the first time of arrival of the first signal from the first antenna and the second time of arrival of the second signal from the second antenna; and transmitting, by the subscriber unit, to the first antenna or the second antenna, a third signal carrying information indicating the determined difference between the first time of arrival of the first signal from the first antenna and the second time of arrival of the second signal from the second antenna, wherein the third signal is spread coded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A code division multiple access (CDMA) subscriber unit comprising:
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a subscriber unit antenna configured to receive a first signal from a first antenna at a first time of arrival, and to receive a second signal from a second antenna at a second time of arrival; and a receiver, coupled to the subscriber unit antenna and a circuit, configured to receive and forward both the first signal from the first antenna and the second signal from the second antenna to the circuit; wherein the circuit is configured to determine a difference between the first time of arrival of the first signal from the first antenna and the second time of arrival of the second signal from the second antenna; wherein the circuit is further configured to transmit, via the subscriber unit antenna, to the first base antenna or the second antenna, a spread coded third signal carrying information indicating the determined difference between the first time of arrival of the first signal from the first antenna and the second time of arrival of the second signal from the second antenna. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A code division multiple access (CDMA) subscriber unit comprising:
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a subscriber unit antenna configured to receive a first signal from a first antenna which has been spread coded via a first pseudorandom code and a second signal from a second antenna which has been spread coded via a second pseudorandom code; and a receiver, coupled to the subscriber unit antenna and a circuit, configured to receive and forward both the first signal from the first antenna which has been spread coded via a first pseudorandom code and the second signal from the second antenna which has been spread coded via the second pseudorandom code; wherein the circuit is configured to determine a difference in chips between a first arrival time of a portion of the first signal and a second arrival time of a portion of the second signal; wherein the circuit is further configured to transmit, via the subscriber unit antenna, to the first antenna or the second antenna, a spread coded third signal carrying information indicating the determined difference between the first arrival time of the portion of the first signal from the first antenna and the second arrival time of the second signal from the second antenna. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification