Apparatus and circuit for processing carrier aggregation

Abstract

A circuit for processing Carrier Aggregation (CA) is provided. The circuit includes a plurality of Component Carrier (CC) processors, each CC processor configured to estimate a frequency offset for a related CC and to compensate the estimated frequency offset, a reference clock generator configured to generate a reference clock using a reference frequency offset as one of frequency offsets output from the plurality of CC processors, a plurality of reception Phase Lock Loop (PLL) units, each reception PLL unit configured to generate a reception carrier frequency for the related CC corresponding to the reference clock, and a plurality of transmission PLL units, each transmission PLL unit configured to generate a transmission carrier frequency for the related CC corresponding to the reference clock.

What is claimed is: 
     
       1. An apparatus for supporting carrier aggregation, the apparatus comprising:
 a plurality of component carrier (CC) circuits, each of the plurality of CC circuits configured to estimate a frequency offset for a related CC; 
 a reference clock generator configured to generate a reference clock using at least one frequency offset of frequency offsets estimated by corresponding two or more of the plurality of CC circuits; and 
 a plurality of phase lock loop (PLL) circuits, each of the plurality of PLL circuits configured to generate a reception carrier frequency or a transmission carrier frequency for at least one related CC corresponding to the at least one frequency offset used in the generating of the reference clock. 
 
     
     
       2. The apparatus of  claim 1 , wherein the plurality of PLL circuits comprises a set of reception PLL circuits configured to generate the reception carrier frequency, and a set of transmission PLL circuits configured to generate the transmission carrier frequency. 
     
     
       3. The apparatus of  claim 1 , further comprising:
 a controller configured to select the at least one frequency offset from the frequency offsets as at least part of a reference frequency offset. 
 
     
     
       4. The apparatus of  claim 1 , further comprising:
 a controller configured to compensate the estimated frequency offset using at least one of the plurality of CC circuits. 
 
     
     
       5. The apparatus of  claim 4 , wherein the controller is further configured to:
 refrain from compensating the estimated frequency offset based at least in part on a determination that the at least one frequency offset is selected as at least part of a reference frequency offset. 
 
     
     
       6. The apparatus of  claim 1 , wherein the plurality of PLL circuits are further configured to:
 compensate the estimated frequency offset corresponding to the at least one related CC. 
 
     
     
       7. The apparatus of  claim 1 , further comprising:
 a controller configured to select the at least one frequency offset based at least in part on channel quality information corresponding to at least one of the plurality of CC circuits. 
 
     
     
       8. The apparatus of  claim 7 , wherein the channel quality information comprises a carrier-to-interference and noise ratio, reference signal received power, reference signal received quality, a reference signal strength indicator, a channel quality indicator, a block error rate, or any combination thereof. 
     
     
       9. The apparatus of  claim 1 , wherein the reference clock generator comprises a temperature compensated crystal oscillator, a voltage controlled-TCXO, or a digitally compensated crystal oscillator. 
     
     
       10. The apparatus of  claim 1 , wherein each of the plurality of CC circuits comprises:
 a plurality of frequency down converters, each of the frequency down converters configured to down-convert a reference reception carrier frequency received from a first corresponding PLL circuit of the plurality of PLL circuits, the first corresponding PLL circuit including a reception PLL circuit; 
 a plurality of frequency up converters, each of the frequency up converters configured to up-convert a reference transmission carrier frequency received from a second corresponding PLL circuit of the plurality of PLL circuits, the second corresponding PLL circuit including a transmission PLL circuit; 
 a frequency offset estimator configured to estimate the at least one frequency offset using a difference between the reference reception carrier frequency and the reception carrier frequency; 
 a reception frequency offset compensator (RFOC) configured to compensate a reception frequency offset converted by corresponding one of the plurality of frequency down converters using the estimated frequency offset; and 
 a transmission frequency offset compensator (TFOC) configured to compensate a transmission frequency offset converted by corresponding one of the plurality of frequency up converters using the estimated frequency offset. 
 
     
     
       11. The apparatus of  claim 10 , wherein the RFOC or the TFOC comprises a phase rotator, a read-only memory table, a complex multiplier based-phase converter, or any combination thereof. 
     
     
       12. The apparatus of  claim 11 , wherein the phase rotator comprises a coordinate rotation digital computer. 
     
     
       13. An apparatus for supporting carrier aggregation, the apparatus comprising:
 a first component carrier (CC) circuit configured to estimate a first frequency offset for a first CC to be processed by the first CC circuit; 
 a second CC circuit configured to estimate a second frequency offset for a second CC to be processed by the second CC circuit; 
 a reference clock generator configured to generate a reference clock using the first frequency offset or the second frequency offset; and 
 a phase lock loop (PLL) circuit configured to generate a reception carrier frequency or a transmission carrier frequency for the first CC or the second CC. 
 
     
     
       14. The apparatus of  claim 13 , wherein the PLL circuit comprises a set of one or more reception PLL circuits configured to generate the reception carrier frequency, and a set of one or more transmission PLL circuits configured to generate the transmission carrier frequency. 
     
     
       15. The apparatus of  claim 13 , further comprising:
 a controller configured to select the first frequency offset or the second frequency offset as at least part of a reference frequency offset. 
 
     
     
       16. The apparatus of  claim 13 , further comprising:
 a controller configured to compensate the estimated first frequency offset or the estimated second frequency offset using a corresponding one of the first CC circuit and the second CC circuit. 
 
     
     
       17. The apparatus of  claim 13 , wherein the PLL circuit is further configured to:
 compensate the estimated first frequency offset or the estimated second frequency offset related to a corresponding one of the first CC and the second CC. 
 
     
     
       18. The apparatus of  claim 13 , further comprising:
 a controller configured to select the first frequency offset or the second frequency offset based at least in part on channel quality information corresponding to at least one of the first CC circuit and the second CC circuit. 
 
     
     
       19. An apparatus for supporting carrier aggregation, the apparatus comprising:
 a first component carrier (CC) circuit configured to: 
 estimate a first frequency offset for a first CC to be processed by the first CC circuit, and 
 compensate the estimated first frequency offset; 
 a second CC circuit configured to: 
 estimate a second frequency offset for a second CC to be processed by the second CC circuit, and 
 compensate the estimated second frequency offset; 
 a reference clock generator configured to generate a reference clock using the first frequency offset or the second frequency offset; and 
 a phase lock loop (PLL) circuit configured to generate a reception carrier frequency or a transmission carrier frequency for the first CC or the second CC. 
 
     
     
       20. The apparatus of  claim 19 , wherein the PLL circuit comprises a set of one or more reception PLL circuits configured to generate the reception carrier frequency, and a set of one or more transmission PLL circuits configured to generate the transmission carrier frequency. 
     
     
       21. An apparatus for performing carrier aggregation, the apparatus comprising:
 a plurality of phase lock loop (PLL) circuits configured to:
 respectively generate a plurality of first carrier frequencies that respectively correspond to a plurality of component carriers (CCs) based on a reference clock, and 
 receive a plurality of second carrier frequencies that respectively correspond to the plurality of CCs; and 
   a reference clock generator configured to generate a reference clock based on comparing at least one of the plurality of first carrier frequencies and corresponding at least one of the plurality of second carrier frequencies.   
     
     
       22. The apparatus of claim 21, wherein the apparatus is a home evolved node B (HeNB), or a repeater. 
     
     
       23. The apparatus of claim 21, wherein the plurality of PLL circuits comprises:
 a set of reception PLL circuits configured to generate the plurality of first carrier frequencies; and   a set of transmission PLL circuits configured to generate a plurality of third carrier frequencies for transmitting signals, the third carrier frequencies respectively corresponding to the plurality of CCs.   
     
     
       24. A method for performing carrier aggregation, the method comprising:
 generating a plurality of first carrier frequencies respectively corresponding to a plurality of component carriers (CCs) based on a reference clock;   receiving a plurality of second carrier frequencies respectively corresponding to the plurality of CCs;   comparing at least one of the plurality of first carrier frequencies with corresponding at least one of the plurality of second carrier frequencies; and   generating a reference clock based on the comparing.   
     
     
       25. The method of claim 24, further comprising:
 compensating for at least one frequency difference that results from the comparison and respectively corresponds to at least one of the plurality of CCs.   
     
     
       26. The method of claim 25, further comprising:
 identifying a reference frequency difference among the at least one frequency difference.   
     
     
       27. The method of claim 26, wherein the reference frequency difference is identified based on information for channel quality corresponding to each of the plurality of CCs. 
     
     
       28. The method of claim 27, wherein each information for channel quality comprises at least one of a carrier-to-interference and noise ratio, reference signal received power, reference signal received quality, a reference signal strength indicator, a channel quality indicator, or a block error rate. 
     
     
       29. An apparatus for performing carrier aggregation, the apparatus comprising:
 a plurality of antennas; and   at least one processor configured to:
 generate a plurality of first carrier frequencies respectively corresponding to a plurality of component carriers (CCs) based on a reference clock, 
   receive, via the plurality of antennas, a plurality of second carrier frequencies respectively corresponding to the plurality of CCs,
 perform a comparison of at least one of the plurality of first carrier frequencies with corresponding at least one of the plurality of second carrier frequencies, and 
 generate a reference clock based on the comparison. 
   
     
     
       30. The apparatus of claim 29, wherein the at least one processor is further configured to compensate for at least one frequency difference that results from the comparison and respectively corresponds to the plurality of CCs. 
     
     
       31. The apparatus of claim 29, wherein the at least one processor is further configured to identify a reference frequency difference among the at least one frequency difference. 
     
     
       32. The apparatus of claim 29, wherein the apparatus is a home evolved node B (HeNB), or a repeater. 
     
     
       33. The apparatus of claim 29, wherein the at least one processor comprises:
 a plurality of frequency down converters, each of the frequency down converters configured to down-convert the generated first carrier frequencies;   a frequency offset estimator configured to perform the comparison between the generated first carrier frequencies and the received second carrier frequencies; and   a frequency offset compensator configured to compensate for at least one frequency difference that results from the comparison and respectively corresponds to at least one of the plurality of CCs.