Transmitter and method using carrier aggregation
Disclosed are a transmitter and method of combining multiple contiguous and non-contiguous frequency bands in a wireless communication system using carrier aggregation. The transmitter includes a first communication unit for converting a first baseband signal into a first RF signal of a first band, a second communication unit for converting a second baseband signal into a second RF signal of a second band, a combiner for outputting a third RF signal by combining the first RF signal and the second RF signal, and an amplifier for amplifying the third RF signal.
1. A transmitter comprising:
a first communication unit configured to convert a first baseband signal into a first radio frequency (RF) signal of a first band;
a second communication unit configured to convert a second baseband signal into a second RF signal of a second band;
a controller configured to determine whether a carrier aggregation (CA) type of the first band and the second band corresponds to intra-band CA or inter-band CA;
a combiner configured to output a third RF signal by combining the first RF signal and the second RF signal, when the CA type corresponds to intra-band CA; and
at least one amplifier configured to amplify the third RF signal when the CA type corresponds to intra-band CA, and configured to independently amplify the first RF signal and the second RF signal when the CA type corresponds to inter-band CA.
2. The transmitter of claim 1 , wherein the first communication unit and the second communication unit each comprise:
a baseband signal processor configured to process the baseband signal;
a mixer configured to convert the baseband signal into an RF signal by using a local oscillation frequency; and
a variable gain controller configured to control a gain of the RF signal.
3. The transmitter of claim 2 , wherein the mixer is configured as an amplifier having a cascade structure.
4. The transmitter of claim 2 , wherein the variable gain controller is configured as a current steering circuit and a resistor to resistor (R2R) attenuator.
5. The transmitter of claim 2 , further comprising a resonance circuit electrically connected to an output terminal of the variable gain controller.
6. The transmitter of claim 5 , further comprising a balun circuit electrically connected to the resonance circuit.
7. The transmitter of claim 2 , further comprising:
a current to voltage converter configured to convert a current signal of the baseband signal into a voltage signal, the current to voltage converter being connected to the mixer;
a filter for removing noise from the baseband signal of which the current signal has been converted into the voltage signal; and
a voltage to current converter configured to convert the voltage signal of the baseband signal from which the noise has been removed into a current signal.
8. The transmitter of claim 7 , further comprising a current mirror configured to copy the baseband signal of which the voltage signal has been converted into the current signal.
9. The transmitter of claim 1 , wherein the first band and the second band correspond to non-contiguous or contiguous intra-band frequencies for uplink CA.
10. The transmitter of claim 1 , wherein the first band and the second band correspond to non-contiguous inter-band frequencies for uplink CA.
11. The transmitter of claim 1 , further comprising a third communication unit configured to convert a third baseband signal into a fourth RF signal of a third band, wherein the combiner is further configured to generate a fifth RF signal by combining the third RF signal and the fourth RF signal.
12. A method of operating a transmitter, the method comprising:
converting a first baseband signal into a first radio frequency (RF) signal of a first band;
converting a second baseband signal into a second RF signal of a second band;
determining whether a carrier aggregation (CA) type of the first band and the second band corresponds to intra-band CA or inter-band CA;
generating a third RF signal by combining the first RF signal and the second RF signal, when the CA type corresponds to intra-band CA; and
amplifying the third RF signal according to the determined CA type when the CA type corresponds to intra-band CA, and configured to independently amplify the first RF signal and the second RF signal when the CA type corresponds to inter-band CA.
13. The method of claim 12 , wherein converting the first baseband signal and converting the second baseband signal comprises:
processing the baseband signal;
converting the baseband signal into an RF signal by using a local oscillation frequency and a mixer; and
controlling a gain of the RF signal.
14. The method of claim 13 , further comprising:
converting a current signal of the baseband signal into a voltage signal, the current to voltage converter being connected to the mixer;
removing noise of the baseband signal of which the current signal has been converted into the voltage signal; and
converting the voltage signal of the baseband signal from which the noise has been removed into a current signal.
15. The method of claim 14 , further comprising copying the baseband signal of which the voltage signal has been converted into the current signal.
16. The method of claim 12 , wherein the first band and the second band correspond to non-contiguous or contiguous intra-band frequencies for uplink CA.
17. The method of claim 12 , wherein the first band and the second band correspond to non-contiguous inter-band frequencies for uplink CA.
18. An integrated circuit comprising:
a first communication unit configured to generate a first radio frequency (RF) signal of a first band by converting a first baseband signal;
a second communication unit configured to generate a second RF signal of a second band by converting a second baseband signal;
a controller configured to determine whether a carrier aggregation (CA) type of the first band and the second band corresponds to intra-band CA or inter-band CA
a combiner configured to generate a third RF signal by combining the first RF signal and the second RF signal, when the CA type corresponds to intra-band CA; and
at least one amplifier for generating an amplified signal by amplifying the third RF signal when the CA type corresponds to intra-band CA, and configured to independently amplify the first RF signal and the second RF signal when the CA type corresponds to inter-band CA.
19. The circuit of claim 18 , wherein the first band and the second band correspond to non-contiguous or contiguous intra-band frequencies for uplink CA.
20. The circuit of claim 18 , wherein the first band and the second band correspond to non-contiguous inter-band frequencies for uplink CA.