Demodulating a wireless signal modulated by phase-shift keying
Assigneeu-blox AG
InventorZhenlan Cheng
Life of this patent
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Abstract
A method and apparatus are provided for demodulating a wireless signal modulated by phase-shift keying. The signal comprises a plurality of symbols. The method includes: obtaining a first sequence of samples based on the signal; converting the first sequence of samples to a first sequence of frequency domain samples; selecting, as a decision variable, the sample that has the maximum magnitude among the first sequence of frequency domain samples; and identifying a symbol or a symbol-transition based on the decision variable.
Claims13
A method of demodulating a wireless signal modulated by phase-shift keying, the wireless signal comprising a plurality of symbols, the method comprising:
- obtaining a first sequence of samples based on the wireless signal;
- converting the first sequence of samples to a first sequence of frequency domain samples;
- selecting, as a decision variable, a sample that has a maximum magnitude among the first sequence of the frequency domain samples;
- and
- identifying a symbol or a symbol-transition based on the decision variable,
- wherein the first sequence of samples starts at a start of a symbol period, and the method further comprises:
- obtaining a second sequence of samples based on the wireless signal, wherein the second sequence of samples ends at the start of the symbol period;
- reversing the second sequence of samples relative to the first sequence of samples;
- converting the reversed second sequence of samples to a second sequence of frequency domain samples;
- and
- selecting, as a reference variable, a sample that has a maximum magnitude among the second sequence of frequency domain samples,
- wherein the identifying the symbol or the symbol-transition comprises comparing the decision variable with the reference variable.
A demodulator for a wireless signal modulated by phase-shift keying, the wireless signal comprising a plurality of symbols, the demodulator comprising:
- an input, configured to obtain a first sequence of samples based on the wireless signal;
- a first frequency-transform block, configured to convert the first sequence of samples to a first sequence of frequency domain samples;
- a first selection block, configured to select, as a decision variable, a sample that has a maximum magnitude among the first sequence of frequency domain samples;
- and
- a decision block, configured to identify a symbol or a symbol-transition based on the decision variable,
- wherein the first sequence of samples starts at a start of a symbol period, and
- the input is configured to obtain a second sequence of samples based on the wireless signal, wherein the second sequence of samples ends at the start of the symbol period,
- wherein the demodulator further comprises:
- a reversal block, configured to reverse the second sequence of samples relative to the first sequence of samples;
- a second frequency-transform block, configured to convert the reversed second sequence of samples to a second sequence of frequency domain samples;
- and
- a second selection block, configured to select, as a reference variable, a sample that has a maximum magnitude among the second sequence of frequency domain samples, and
- wherein the decision block is configured to identify the symbol or symbol-transition by comparing the decision variable with the reference variable.
Dependencies are inferred from the claim text.