Method and apparatus for locating a mobile station in a spread spectrum communication system

A method for locating a mobile station in a spread spectrum communication system, the method comprising the steps of:

• receiving by a first base station a signal transmitted from the mobile station;
• demodulating the signal by the first base station to form a demodulated signal;
• remodulating at least a portion of the demodulated signal to form a reference signal;
• receiving by the first base station and a second base station a retransmitted signal;
• comparing, by the first base station, the retransmitted signal with the reference signal to determine a first delay;
• comparing, by the second base station, the retransmitted second signal with the reference signal to determine a second delay;
• and
• based on the first and second delays, determining a location of the mobile station.

An apparatus for locating a mobile station in a spread spectrum communication system, the apparatus comprising:

• a first base station responsive to the mobile station, the first base station comprising:
• a first antenna transmitting a first signal to the mobile station, the first antenna receiving a second signal from the mobile station in response to the first signal;
• a first demodulator responsive to the second signal, producing a demodulated signal;
• a reencoder responsive to the demodulated signal, forming a reference signal;
• a first correlator, comparing the reference signal to a retransmitted second signal received by the first antenna to determine a first delay, the first delay representing a travel time of the retransmitted second signal from the mobile station to the first base station;
• a second base station responsive to the mobile station and the reference signal, the second base station comprising:
• a second antenna receiving the retransmitted second signal from the mobile station and receiving the reference signal;
• a second correlator, comparing the reference signal to the retransmitted second signal to determine a second delay, the second delay representing a travel time of the retransmitted second signal from the mobile station to the second base station;
• and
• a controller responsive to the first and second base stations, the controller determining a location of the mobile station based on the first delay and the second delay.

A method for locating a mobile station in a spread spectrum communication system, the method comprising the steps of:

• receiving by a first base station a signal transmitted by the mobile station, the signal comprising a received frame, the received frame having a plurality of received symbols;
• storing the signal by the first base station in a first memory;
• receiving the signal by a second base station;
• storing the signal by the second base station in a second memory;
• demodulating the received frame by the first base station to form a demodulated frame;
• receiving the demodulated frame by the second base station;
• at the first base station, reencoding the demodulated frame to form a reencoded frame, the reencoded frame having a plurality of encoded symbols;
• at the second base station, reencoding the demodulated frame to form the reencoded frame;
• at the first base station, comparing at a first plurality of times each of the plurality of received symbols in the first memory with each of the plurality of reencoded symbols;
• based on the comparisons at the first plurality of times, determining a first delay representing a travel time of the signal from the mobile station to the first base station;
• at the second base station, comparing at a second plurality of times each of the plurality of received symbols in the second memory with each of the plurality of reencoded symbols;
• based on the comparisons at the second plurality of times, determining a second delay representing a travel time of the signal from the mobile station to the second base station;
• and
• based on the first and second delays, determining a location of the mobile station.