Synchronisation in a receiver
AssigneeThe University of Bristol
InventorsMark Beach, Christopher Williams
Life of this patent
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Abstract
A radio receiver is suitable for use in an OFDM wireless communications system, in which it is necessary to identify a timing point at a start of a frame. In order to ensure optimum performance of the receiver in multipath environments, it should be synchronised with the first received multipath component, although one or more of the delayed multipath components may be stronger than the first component. A method of determining the time position of the first received multipath component, determines a correlator function from the received signal, and determines the required timing point from a falling edge in a derivative of the correlator function.
Claims18
A method of detecting a time of receipt of a received radio signal, the received radio signal including at least one multipath component of a transmitted signal, the method comprising:
- determining a correlation function corresponding to a value of a correlation between the received radio signal and a correlation signal;
- forming a derivative of the correlation function;
- detecting a falling edge of the derivative of the correlation function;
- and
- detecting the time of receipt of the received radio signal on the basis of a time position of said falling edge.
A method as claimed in any preceding claim, comprising:
- low pass filtering the derivative of the correlation function;
- and
- detecting a falling edge of the derivative of the correlation function by determining a time position at which the low pass filtered derivative of the correlation function starts to fall.
A method as claimed in any preceding claim, comprising:
- detecting a falling edge of the derivative of the correlation function for a plurality of frames of the received signal;
- median filtering the detected positions of the falling edges in said frames;
- and
- detecting the time of receipt of the received radio signal on the basis of the median filtered time positions of said falling edges.
A radio receiver, for detecting a time of receipt of a received radio signal, the received radio signal including at least one multipath component of a transmitted signal, wherein the radio comprises:
- a processor, for determining a correlation function corresponding to a value of a correlation between the received radio signal and a correlation signal;
- and
- for detecting the time of receipt of the received radio signal on the basis of a time position of a falling edge of a derivative of the correlation function.
Dependencies are inferred from the claim text.