Method and Apparatus for Generating OFDM Signals
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsJohan Hill, Michael Breschel
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Abstract
A method in a transmitter circuit (200) of generating a signal comprising a first sequence of OFDM symbols, which are to be transmitted within a frequency sub band of a second sequence of OFDM symbols is disclosed. A first CP of the second sequence of OFDM symbols has a first duration, and a second CP of the second sequence of OFDM symbols has a second duration. In order to generate both the first and the second cyclic prefix with an integer number of equidistant samples, a first sampling rate is required. The method comprises generating (100) the signal comprising the first sequence of OFDM symbols at a second sampling rate, lower than the first sampling rate, and adjusting (110) a sampling phase during CPs.
Claims24
1-23. (canceled)
A method in a transmitter circuit of generating a signal comprising a first sequence of an integer number Nsym of OFDM symbols, which are to be transmitted within a frequency sub band of a second sequence of Nsym OFDM symbols, wherein
- the first sequence of OFDM symbols and the second sequence of OFDM symbols are to be transmitted with the same timing;
- a first cyclic prefix of the second sequence of OFDM symbols has a first duration;
- a second cyclic prefix of the second sequence of OFDM symbols has a second duration;
- and
- the second duration is shorter than the first duration, such that in order to generate both the first and the second cyclic prefix with an integer number of equidistant samples, a first sampling rate is required;
- wherein the method comprises:
- generating the signal comprising the first sequence of OFDM symbols at a second sampling rate, lower than the first sampling rate;
- adjusting a sampling phase during cyclic prefixes.
A transmitter circuit for generating a signal comprising a first sequence of an integer number Nsym of OFDM symbols, which are to be transmitted within a frequency sub band of a second sequence of Nsym OFDM symbols, wherein
- the first sequence of OFDM symbols and the second sequence of OFDM symbols are to be transmitted with the same timing;
- a first cyclic prefix of the second sequence of OFDM symbols has a first duration;
- a second cyclic prefix of the second sequence of OFDM symbols has a second duration;
- and
- the second duration is shorter than the first duration, such that in order to generate both the first and the second cyclic prefix with an integer number of equidistant samples, a first sampling rate is required;
- wherein the transmitter circuit comprises
- a digital-to-analog converter configured to generate the signal comprising the first sequence of OFDM symbols at a second sampling rate, lower than the first sampling rate;
- and
- a control circuit configured to adjust a sampling phase of the digital-to-analog converter during cyclic prefixes.
Dependencies are inferred from the claim text.