Method of synchronizing a receiver, and a receiver
AssigneeNokia Corporation
InventorIlkka Kontola
Life of this patent
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Abstract
The invention relates to a method for synchronizing a receiver (1) with a transmitted code-modulated spread spectrum signal. The method uses at least one reference code (r(x)), which corresponds to a code used in the modulation. The frequency shift of the transmitted signal and the code phase of the code used in the modulation are determined in the method.
Claims67
A method for synchronizing a receiver with a transmitted code-modulated spread spectrum signal, the method comprising performing a search in frequency versus code-phase space to determine a carrier frequency shift of the code-modulated spread spectrum signal received at the receiver and a code phase of a code used in modulation of the code-modulated spread spectrum signal, the search including:
- 1). performing a correlation between a set of sample vectors formed from the received code-modulated spread spectrum signal and a reference code to produce a set of correlation results, the reference code corresponding to the code used in modulation of the code-modulated spread spectrum signal;
- 2). forming a correlation function matrix from said set of correlation results said correlation function matrix comprising the correlation results of a correlation between the set of sample vectors and the reference code with different phase differences for each sample vector;
- 3). performing a time-to-frequency domain transformation on a basis of a transpose of said correlation function matrix to form a coherent search matrix;
- and
- 4). determining the carrier frequency shift of the code-modulated spread spectrum signal received at the receiver and the code phase of the code used in modulation of the code-modulated spread spectrum signal by examining values of elements of said coherent search matrix.
A receiver comprising a synchronization unit for synchronizing the receiver with a transmitted code-modulated spread spectrum signal by performing a search in frequency versus code-phase space to determine a carrier frequency shift of the code-modulated spread spectrum signal received at the receiver and a code phase of a code used in modulation of the code-modulated spread spectrum signal, wherein the synchronization unit is arranged to:
- 1). perform a correlation between a set of sample vectors formed from the received code-modulated spread spectrum signal and a reference code to produce a set of correlation results, the reference code corresponding to a code used in modulation of the code-modulated spread spectrum signal;
- 2). form a correlation function matrix from said set of correlation results, said correlation function matrix comprising the correlation results of a correlation between the set of sample vectors and the reference code with different phase differences for each sample vector;
- 3). perform a time-to-frequency domain transformation on a basis of a transpose of said correlation function matrix to form a coherent search matrix;
- and
- 4). determine the carrier frequency shift of the code-modulated spread spectrum signal received at the receiver and the code phase of the code used in modulation of the code-modulated spread spectrum signal by examining values of elements of said coherent search matrix.
An electronic device comprising a positioning receiver, the positioning receiver comprising a synchronization unit for synchronizing the positioning receiver with a transmitted code-modulated spread spectrum signal by performing a search in frequency versus code-phase space to determine a carrier frequency shift of the code-modulated spread spectrum signal received by the positioning receiver and a code phase of a code used in modulation of the code-modulated spread spectrum signal, wherein the synchronization unit is arranged to:
- 1). perform a correlation between a set of sample vectors formed from the received code-modulated spread spectrum signal and a reference code to produce a set of correlation results, the reference code corresponding to a code used in modulation of the code-modulated spread spectrum signal;
- 2). form a correlation function matrix from said set of correlation results, said correlation function matrix comprising the correlation results of a correlation between the set of sample vectors and the reference code with different phase differences for each sample vector;
- 3). perform a time-to-frequency domain transformation on a basis of a transpose of said correlation function matrix to form a coherent search matrix;
- and
- 4). determine the carrier frequency shift of the code-modulated spread spectrum signal received by the positioning receiver and the code phase of the code used in modulation of the code-modulated spread spectrum signal by using examining values of elements of the coherent search matrix.
Dependencies are inferred from the claim text.