Downlink observed time difference measurements

A method of using a mobile communication station in a wireless communication network to measure respective times of arrival of Code Division Multiple Access (CDMA) radio signals respectively transmitted by at least two radio transmitters in the network, said method comprising the steps of:

• providing information indicative of when the CDMA radio signals are expected to arrive at the mobile communication station;
• providing information indicative of spreading codes used by the at least two radio transmitters;
• determining, by the mobile communication station and from the information indicative of the spreading codes, the spreading codes used by the at least two radio transmitters;
• and
• the mobile communication station monitoring for arrival of the CDMA radio signals of broadcast channels associated with the at least two radio transmitters using the spreading codes and based upon the information indicative of when the CDMA radio signals are expected to arrive.

A method of locating the position of a mobile communication station in a wireless communication network, comprising:

• receiving spreading code information;
• determining from the received spreading code information the spreading codes used by at least two radio transmitters in the wireless communication network;
• measuring at the mobile communication station respective times of arrival of Code Division Multiple Access (CDMA) radio signals respectively transmitted by the at least two radio transmitters in the network, including providing information indicative of when the CDMA radio signals are expected to arrive at the mobile communication station, and the mobile communication station monitoring for arrival of the CDMA radio signals using the spreading codes and based upon the information indicative of when the CDMA radio signals are expected to arrive;
• and
• using the measured times of arrival to locate the position of the mobile communication station.

A method of determining the time of arrival of a Code Division Multiple Access (CDMA) radio signal from at least two radio transmitters at a radio communication station operating in a wireless communication network, said method comprising the steps of:

• obtaining from the wireless communication network information from which an informational content of the CDMA radio signal can be determined but which information does not itself reveal the informational content of the CDMA radio signal;
• determining the informational content of the CDMA radio signal in response to the information;
• receiving code group identification information and generating long codes therefrom;
• monitoring for arrival of CDMA radio signals during a predetermined time interval in response to the information and the long codes;
• and
• using the informational content of the CDMA radio signal to measure the time of arrival of the CDMA radio signal.

An apparatus for use in locating the position of a mobile communication station in a wireless communication network, comprising:

• a determiner for determining when each of a plurality of Code Division Multiple Access (CDMA) radio signals from at least two radio transmitters is expected to arrive at the mobile communication station;
• a radio signal monitor for measuring respective times of arrival of the CDMA radio signals, said radio signal monitor provided in the mobile communication station and having an input coupled to said determiner to receive therefrom information indicative of when the CDMA radio signals are expected to arrive at the mobile communication station, said monitor responsive to said information to monitor for arrival of the CDMA radio signals;
• and
• a code generator coupled to said radio signal monitor for providing thereto codes, the radio signal monitor using the codes to monitor for arrival of the CDMA radio signals.

An apparatus for measuring the time of arrival of a Code Division Multiple Access (CDMA) radio signal thereat, comprising:

• an input for receiving information from which an informational content of the CDMA radio signal can be determined but which information does not itself reveal the informational content of the CDMA radio signal;
• a determiner coupled to said input and responsive to said information for determining the informational content of the CDMA radio signal;
• a code generator for receiving code group identification information and generating long codes therefrom;
• and
• a radio signal monitor for measuring the time of arrival of the CDMA radio signal, said radio signal monitor coupled to said determiner for using said informational content of the CDMA radio signal in measuring the time of arrival of the CDMA radio signal, said radio signal monitor coupled to said code generator for receiving the long codes and for monitoring for arrival of the CDMA radio signals during a predetermined time interval in response to the information and the long codes.

A method of using a mobile communication station in a wireless communication network to measure respective times of arrival of Code Division Multiple Access (CDMA) radio signals respectively transmitted by at least two radio transmitters in the network, comprising:

• providing information indicative of when the radio signals are expected to arrive at the mobile communication station;
• and
• the mobile communication station monitoring for arrival of the radio signals in response to the information including the steps of:
• correlating said radio signal with a first code that is periodically transmitted by the associated radio transmitter;
• and
• simultaneously with said correlating step, correlating said radio signal with a code pattern that includes a plurality of second codes which are sequentially transmitted by the associated radio transmitter such that each of the second codes in the code pattern is transmitted simultaneously with one of said periodic transmissions of the first code.