Reduced complexity timing estimation for locating the position of a mobile terminal
First Claim
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1. A method of estimating the arrival time of a received reference signal, said method comprising:
- scheduling, by a scheduler, a first set of timing hypotheses spanning one or more OFDM symbols for one or more cells;
detecting, by a detector, one or more reference signals corresponding to the first set of timing hypotheses by, for each hypothesis;
converting one or more OFDM symbols from a time domain into a frequency domain;
computing channel estimates by correlating one or more frequency domain OFDM symbols with a known reference signal based on said timing hypothesis;
computing timing based on said channel estimates;
computing, by said detector, timing estimates based on said detected reference signals;
reporting, by said detector, said timing estimates for the detected reference signals to said scheduler; and
scheduling a second set of timing hypotheses based on the reported timing of the detected reference signals.
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Abstract
A method and corresponding apparatus are provided to reduce the complexity of calculations needed to determine the time of arrival of position reference signals transmitted from multiple cells. A scheduler determines at a given instance what portions of a search grid or search window to search. A timing estimation circuit operating under the control of the scheduler computes timing estimates and reports the timing estimates back to the scheduler. The scheduler uses the timing estimates reported by the detection circuit to scheduler subsequent searches of the search grid or search window.
18 Citations
22 Claims
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1. A method of estimating the arrival time of a received reference signal, said method comprising:
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scheduling, by a scheduler, a first set of timing hypotheses spanning one or more OFDM symbols for one or more cells; detecting, by a detector, one or more reference signals corresponding to the first set of timing hypotheses by, for each hypothesis; converting one or more OFDM symbols from a time domain into a frequency domain; computing channel estimates by correlating one or more frequency domain OFDM symbols with a known reference signal based on said timing hypothesis; computing timing based on said channel estimates; computing, by said detector, timing estimates based on said detected reference signals; reporting, by said detector, said timing estimates for the detected reference signals to said scheduler; and scheduling a second set of timing hypotheses based on the reported timing of the detected reference signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A timing estimation circuit for estimating the arrival time of a received reference signals, said timing estimation circuit comprising a detection circuit and a scheduler:
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said detection circuit being configured to; detect reference signals corresponding to a first set of timing hypotheses provided by a scheduler; compute timing estimates based on said detected reference signals by, for each hypothesis; converting one or more OFDM symbols from a time domain into a frequency domain; computing channel estimates by correlating one or more frequency domain OFDM symbols with a known reference signal based on said timing hypothesis; computing timing based on said channel estimates; report said timing estimates for the detected reference signals to said scheduler; and said scheduler being configured to; schedule said first set of timing hypotheses so as to span one or more OFDM symbols for one or more cells to be processed by said detection circuit; and schedule a second set of timing hypotheses to be processed by said detection circuit based on said reported timing estimates provided by said detection circuit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification