IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
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출원번호 |
UP-0860274
(2001-05-17)
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등록번호 |
US-7688899
(2010-04-23)
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발명자
/ 주소 |
- Ketchum, John W.
- Howard, Steven J.
- Walton, Jay Rod
- Wallace, Mark S.
- Ling, Fuyun
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
12 인용 특허 :
42 |
초록
▼
Techniques to process data for transmission over a set of transmission channels selected from among all available transmission channels. In an aspect, the data processing includes coding data based on a common coding and modulation scheme to provide modulation symbols and pre-weighting the modulatio
Techniques to process data for transmission over a set of transmission channels selected from among all available transmission channels. In an aspect, the data processing includes coding data based on a common coding and modulation scheme to provide modulation symbols and pre-weighting the modulation symbols for each selected channel based on the channel's characteristics. The pre-weighting may be achieved by “inverting” the selected channels so that the received SNRs are approximately similar for all selected channels. With selective channel inversion, only channels having SNRs at or above a particular threshold are selected, “bad” channels are not used, and the total available transmit power is distributed across only “good” channels. Improved performance is achieved due to the combined benefits of using only the Ns best channels and matching the received SNR of each selected channel to the SNR required by the selected coding and modulation scheme.
대표청구항
▼
What is claimed is: 1. A method for processing data for transmission over multiple transmission channels in a multi-channel communication system, comprising: determining characteristics of a plurality of transmission channels available for data transmission; selecting one or more available transmis
What is claimed is: 1. A method for processing data for transmission over multiple transmission channels in a multi-channel communication system, comprising: determining characteristics of a plurality of transmission channels available for data transmission; selecting one or more available transmission channels based on the determined characteristics and a threshold, wherein the multi-channel communication system is a multiple-input multiple-output (MIMO) communication system, and wherein the plurality of available transmission channels correspond to a plurality of spatial subchannels of a MIMO channel; coding data for all selected transmission channels based on a common coding scheme to provide coded data; modulating the coded data for all selected transmission channels based on a common modulation scheme having a corresponding signal constellation to provide modulation symbols; and weighting modulation symbols for the selected transmission channel based on a respective weight indicative of a transmit power level for the selected transmission channel and derived based in part on the determined characteristics of the selected transmission channel, wherein use of the common coding scheme and the common modulation scheme results in approximately the same bit rate for each selected channel. 2. The method of claim 1, wherein the weights for the selected transmissions are derived to distribute total available transmit power among all selected transmission channels to achieve similar received quality for modulation symbols received via the selected transmission channels. 3. The method of claim 2, wherein the received quality is estimated by signal-to-noise-plus-interference ratios (SNRs). 4. The method of claim 1, wherein the determined characteristics for the available transmission channels are channel gains. 5. The method of claim 4, wherein transmission channels having power gains greater than or equal to a particular power gain threshold are selected, and wherein the power gains are determined based on the channel gains. 6. The method of claim 1, wherein the determined characteristics for the available transmission channels are received signal-to-noise-plus-interference ratios (SNRs). 7. The method of claim 6, wherein transmission channels having SNRs greater than or equal to a particular SNR threshold are selected. 8. The method of claim 1, wherein the determined characteristics for the available transmission channels are expressed via power control information. 9. The method of claim 8, wherein the power control information is indicative of requests for changes in power level. 10. The method of claim 1, wherein the weights for the selected transmission channels is further determined based on total transmit power available for data transmission. 11. The method of claim 1, wherein the weights for the selected transmission channels is further derived based on a normalization factor, which is determined based on the characteristics of the selected transmission channels. 12. The method of claim 1, wherein the threshold is selected to provide high throughput for the selected transmission channels. 13. The method of claim 1, wherein the threshold is selected to provide a highest throughput for the available transmission channels. 14. The method of claim 1, wherein the threshold is derived based on a particular target SNR for all selected transmission channels. 15. The method of claim 1, further comprising: transmitting the weighted modulation symbols on the selected transmission channels. 16. The method of claim 1, wherein the multi-channel communication system is an orthogonal frequency division modulation (OFDM) system, and wherein the plurality of available transmission channels correspond to a plurality of frequency subchannels. 17. The method of claim 1, wherein the MIMO communication system utilize OFDM, and wherein the plurality of available transmission channels correspond to spatial subchannels of a plurality of frequency subchannels. 18. A method for transmitting data over multiple transmission channels in a multi-channel communication system, comprising: determining characteristics of each of a plurality of transmission channels available for data transmission; selecting one or more available transmission channels based on the determined characteristics, wherein the multi-channel communication system is a multiple-input multiple-output (MIMO) communication system, and wherein the plurality of available transmission channels correspond to a plurality of spatial subchannels of a MIMO channel; coding data for selected ones of the available transmission channels to provide coded data, wherein the data for the selected transmission channels is coded based on a common coding scheme; modulating the coded data to provide modulation symbols wherein the modulation symbols for the selected transmission channels are derived based on a common modulation scheme having a corresponding signal constellation; and weighting modulation symbols for the selected transmission channel based on a respective weight indicative of a transmit power level for the selected transmission channels and derived based in part on the determined characteristics of the selected transmission channels; and transmitting the weighted modulation symbols on the selected transmission channels, wherein use of the common coding scheme and the common modulation scheme results in approximately the same bit rate for each selected channel. 19. The method of claim 18, wherein the common coding scheme is selected from among a plurality of possible coding schemes. 20. The method of claim 18, wherein the common modulation scheme is selected from among a plurality of possible modulation schemes. 21. The method of claim 18, further comprising: selecting one or more of the available transmission channels for data transmission based on the determined characteristics of the channels and a threshold. 22. A transmitter unit in a multi-channel communication system, comprising: a controller configured to receive channel state information (CSI) indicative of characteristics of a plurality of transmission channels available for data transmission and to select one or more available transmission channels based on the channel characteristics and a threshold, wherein the multi-channel communication system is a multiple-input multiple-output (MIMO) communication system, and wherein the plurality of available transmission channels correspond to a plurality of spatial subchannels of a MIMO channel; a transmit data processor coupled to the controller configured to receive and code data for all selected transmission channels based on a common coding scheme to provide coded data, modulate the coded data for all selected transmission channels based on a common modulation scheme having a corresponding signal constellation to provide modulation symbols, and weight modulation symbols for the selected transmission channels based on a respective weight, wherein each weight is indicative of a transmit power level for the corresponding selected transmission channels and is derived based in part on the characteristics of the selected transmission channels, wherein use of the common coding scheme and the common modulation scheme results in approximately the same bit rate for each selected channel. 23. The transmitter of claim 22, wherein the controller is further configured to select the coding and modulation schemes based on the characteristics of the available transmission channels and to provide one or more control signals indicative of the selected coding and modulation schemes. 24. The transmitter of claim 22, wherein the controller is further configured to determine the threshold based on the characteristics of the available transmission channels. 25. The transmitter of claim 22, further comprising: a transmit channel processor coupled to the transmit data processor and configured to receive and demultiplex the weighted modulation symbols for the selected transmission channels into a plurality of streams, one stream for each antenna used to transmitted the data. 26. The transmitter of claim 22, wherein the CSI comprise signal-to-noise-plus-interference ratio (SNR) estimates for the available transmission channels. 27. The transmitter of claim 22, wherein the CSI comprise channel gain estimates for the available transmission channels. 28. The transmitter of claim 22, wherein the CSI comprise power control information for the available transmission channels. 29. The transmitter of claim 22, wherein the transmitter unit is operative to transmit data on a downlink in the communication system. 30. The transmitter of claim 22, wherein the transmitter unit is operative to transmit data on an uplink in the communication system. 31. The method of claim 1, wherein the multi-channel communication system is an orthogonal frequency division modulation (OFDM) system, and wherein the plurality of available transmission channels corresponds to a plurality of frequency subchannels for a time slot. 32. The method of claim 31, wherein the time slot corresponds to a particular time interval. 33. The method of claim 18, wherein the multi-channel communication system is an orthogonal frequency division modulation (OFDM) system, and wherein the plurality of available transmission channels corresponds to a plurality of frequency subchannels for a time slot. 34. The method of claim 33, wherein the time slot corresponds to a particular time interval. 35. The method of claim 33, wherein the time slot corresponds to one OFDM symbol. 36. The transmitter unit of claim 22, wherein the multi-channel communication system is an orthogonal frequency division modulation (OFDM) system and wherein the plurality of available transmission channels corresponds to a plurality of frequency subchannels for a time slot, and wherein the controller is configured to select one or more frequency subchannels for the time slot. 37. The transmitter unit of claim 36, wherein the time slot corresponds to a particular time interval. 38. The transmitter unit of claim 36, wherein the time slot corresponds to one OFDM symbol. 39. A transmitter unit in a multi-channel communication system, comprising: means for determining characteristics of a plurality of transmission channels available for data transmission; means for selecting one or more available transmission channels based on the determined characteristics and a threshold, wherein the multi-channel communication system is a multiple-input multiple-output (MIMO) communication system, and wherein the plurality of available transmission channels correspond to a plurality of spatial subchannels of a MIMO channel; means for coding data for all selected transmission channels based on a common coding scheme to provide coded data; means for modulating the coded data for all selected transmission channels based on a common modulation scheme having a corresponding signal constellation to provide modulation symbols; and means for weighting modulation symbols for the selected transmission channel based on a respective weight indicative of a transmit power level for the selected transmission channels and derived based in part on the determined characteristics of the selected transmission channels, wherein use of the common coding scheme and the common modulation scheme results in approximately the same bit rate for each selected channel. 40. The apparatus of claim 39, further comprising means for deriving the weights to distribute total available transmit power among all selected transmission channels to achieve similar received quality for modulation symbols received via the selected transmission channels. 41. The apparatus of claim 40, wherein the received quality is an estimated signal-to-noise-plus-interference ratios (SNRs). 42. The apparatus of claim 39, wherein the means for determining comprises means for determining channel gains. 43. The apparatus of claim 39, wherein the means for weighting comprises means for weighting based on total transmit power available for data transmission. 44. The apparatus of claim 39, wherein the means for weighting comprises means for weighting based on a normalization factor, which is determined based on the characteristics of the selected transmission channels. 45. The apparatus of claim 39, wherein the multi-channel communication system is an orthogonal frequency division modulation (OFDM) system, and wherein the plurality of available transmission channels corresponds to a plurality of frequency subchannels. 46. The apparatus of claim 39, wherein the multi-channel communication system is an orthogonal frequency division modulation (OFDM) system and wherein the plurality of available transmission channels corresponds to a plurality of frequency subchannels for a time slot, and wherein the controller is configured to select one or more frequency subchannels for the time slot. 47. The apparatus of claim 46, wherein the time slot corresponds to a particular time interval. 48. The apparatus of claim 46, wherein the time slot corresponds to one OFDM symbol. 49. The method of claim 31, wherein the time slot corresponds to one OFDM symbol.
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