Method of and apparatus for estimating a characteristic of a signal
First Claim
1. A method of estimating a characteristic of a first signal having at least partly a varying information content, the method comprising the steps of, in a receiver:
- receiving, from a first transmitter, the first signal;
receiving, from a second transmitter remote from the first transmitter, a second signal comprising assistance data comprising compressed data having a known relationship to the information content of the first signal;
in response to the second signal, deriving an expected third signal in which said expected third signal is a replica of at least a part of the first signal;
and correlating the first signal with the expected third signal to estimate the characteristic of the first signal.
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Abstract
This invention relates to a method of estimating a characteristic of a signal such as a time of arrival or a transmitter identity in particular in a cellular communication system. Most known techniques have limited performance as they rely on limited amounts of known data. The method of the invention comprise a first step (201) of receiving the signal at a subscriber unit. In a second step (203) the subscriber unit receives assistance data from the fixed network and in a third step (205) an expected signal is derived in response to this assistance data. For GSM the assistance data can be a frame number and a BSIC permitting an entire expected SCH burst to be derived. In a fourth (207) step the signal characteristic is determined by correlation of the received signal and the expected signal. The invention is particularly applicable to location determination in a GSM communication system.
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Citations
14 Claims
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1. A method of estimating a characteristic of a first signal having at least partly a varying information content, the method comprising the steps of, in a receiver:
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receiving, from a first transmitter, the first signal;
receiving, from a second transmitter remote from the first transmitter, a second signal comprising assistance data comprising compressed data having a known relationship to the information content of the first signal;
in response to the second signal, deriving an expected third signal in which said expected third signal is a replica of at least a part of the first signal;
and correlating the first signal with the expected third signal to estimate the characteristic of the first signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification