IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0415725
(2006-05-02)
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등록번호 |
US-8102882
(2012-01-24)
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발명자
/ 주소 |
- Wang, Haifeng
- Wang, Fang
- Chen, Ming
- Cheng, Shixin
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출원인 / 주소 |
|
대리인 / 주소 |
Hollingsworth & Funk, LLC
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인용정보 |
피인용 횟수 :
10 인용 특허 :
1 |
초록
▼
A multicarrier data transmission scheme is provided. According to the provided scheme, a radio transmitter encodes data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit. The data bits are preferably encoded w
A multicarrier data transmission scheme is provided. According to the provided scheme, a radio transmitter encodes data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit. The data bits are preferably encoded with an irregular low-density parity check (LDPC) code. The encoded data bits are then mapped to symbols. The symbols are allocated to subcarriers of a multicarrier radio signal on the basis of channel state information obtained from the radio receiver and the degree used with respect to each symbol. On the basis of the channel state information, a number of subcarriers are truncated due to high attenuation, and the number of subcarriers to be truncated relative to the total number of subcarriers is substantially fixed. The available transmit power to the non-truncated subcarriers. The multicarrier signal comprising symbols on the non-truncated subcarriers is then transmitted to the radio receiver.
대표청구항
▼
1. A method comprising: obtaining, in a radio transmitter of a wireless multicarrier communication system, channel state information describing attenuation effected by a radio channel to subcarriers used in the data transmission;encoding, in the radio transmitter, different portions of a plurality o
1. A method comprising: obtaining, in a radio transmitter of a wireless multicarrier communication system, channel state information describing attenuation effected by a radio channel to subcarriers used in the data transmission;encoding, in the radio transmitter, different portions of a plurality of data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit;mapping, in the radio transmitter, encoded data bits to symbols;allocating, in the radio transmitter, the symbols to subcarriers on the basis of the channel state information and the degree of encoded bits associated with each symbol;determining, in the radio transmitter on the basis of the channel state information, a number of subcarriers to be truncated due to high attenuation, the number of subcarriers to be truncated relative to the total number of subcarriers being substantially fixed;allocating symbols comprising encoded data bits protected by higher number of parity check equations on the subcarriers that are not determined to be truncated and allocating symbols comprising encoded data bits protected by lower number of parity check equations on the subcarriers that are determined to be truncated;truncating, in the radio transmitter, the determined subcarriers and symbols on the determined subcarriers;allocating, in the radio transmitter, the available transmit power to the non-truncated subcarriers, andtransmitting a multicarrier signal comprising symbols on the non-truncated subcarriers. 2. The method of claim 1, wherein the plurality of data bits is encoded with an irregular low-density parity check (LDPC) channel code. 3. The method of claim 1, wherein the available transmit power is allocated on the basis of the channel state information. 4. The method of claim 3, wherein the available transmit power is allocated to each of the non-truncated subcarriers proportionally to the attenuation of the corresponding non-truncated subcarrier, the attenuation being described by the channel state information. 5. The method of claim 4, wherein more transmit power is allocated to heavily attenuating subcarriers and less transmit power is allocated to the mildly attenuating subcarriers. 6. The method of claim 1, wherein the allocation of symbols to subcarriers is carried out by allocating symbols, each comprising one or more data bits encoded with a high degree, to less-attenuating subcarriers and symbols, each comprising one or more data bits encoded with a low degree, to heavily attenuating subcarriers. 7. The method of claim 1, wherein the channel state information is received from a radio receiver and the multicarrier signal comprising the symbols on the non-truncated subcarriers is transmitted to the radio receiver from which the channel state information was received. 8. The method of claim 1, further comprising omitting transmission of symbols allocated to the truncated subcarriers in response to the truncation of the determined subcarriers. 9. An apparatus comprising: a processing unit; and memory including computer program code, the memory and computer program code configured to, with the processing unit, cause the apparatus at least to: obtain channel state information describing attenuation effected by a radio channel to subcarriers the apparatus uses in data transmission, encode different portions of a plurality of data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit, map encoded data bits to symbols, allocate the symbols to subcarriers on the basis of the channel state information and the degree of encoded bits associated with each symbol, determine, on the basis of the channel state information, a number of subcarriers to be truncated due to high attenuation, the number of subcarriers to be truncated relative to the total number of subcarriers used in the data transmission being substantially fixed, allocate symbols comprising encoded data bits protected by higher number of parity check equations on subcarriers that are determined to not be truncated and allocate symbols comprising encoded data bits protected by lower number of parity check equations on subcarriers that are determined to be truncated, truncate the determined subcarriers and symbols on the determined subcarriers, allocate the available transmit power to the non-truncated subcarriers, and control the apparatus to transmit a multicarrier signal comprising the symbols on the non-truncated subcarriers. 10. The apparatus of claim 9, wherein the processing unit is further configured to encode the plurality of data bits with irregular low-density parity check (LDPC) channel codes. 11. The apparatus of claim 9, wherein the processing unit is further configured to allocate the available transmit power on the basis of the channel state information. 12. The apparatus of claim 11, wherein the processing unit is further configured to allocate the available transmit power to each of the non-truncated subcarriers proportionally to the attenuation of the corresponding non-truncated subcarrier, the attenuation being described by the channel state information. 13. The apparatus of claim 11, wherein the processing unit is further configured to allocate more transmit power to heavily attenuating subcarriers and less transmit power is allocated to the mildly attenuating subcarriers. 14. The apparatus of claim 9, wherein the processing unit is further configured to carry out the allocation of symbols to subcarriers by allocating symbols, each comprising one or more data bits encoded with high degree, to less-attenuating subcarriers and symbols, each comprising one or more data bits encoded with low degree, to heavily attenuating subcarriers. 15. The apparatus of claim 9, wherein the processing unit is further configured to receive the channel state information from a radio receiver, and transmit the multicarrier signal comprising the symbols on the non-truncated subcarriers to the radio receiver from which the channel state information was received. 16. The radio transmitter of claim 9, wherein the processing unit is further configured to control the radio transmitter to omit transmission of symbols allocated to the truncated subcarriers in response to the truncation of the determined subcarriers. 17. An apparatus comprising: a processing unit; andmemory including computer program code, the memory and computer program code configured to, with the processing unit, cause the apparatus at least: to obtain channel state information from a signal received from a radio transmitter, the channel state information describing attenuation effected by a radio channel to subcarriers of a multicarrier signal the radio transmitter uses in data transmission, to transmit the channel state information to the radio transmitter, to receive a multicarrier signal comprising a plurality of subcarriers carrying symbols through the communication interface, wherein the symbols have been allocated to the subcarriers on the basis of the channel state information and degree of encoded bits associated with each symbol, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit such that symbols comprising encoded data bits protected by higher number of parity check equations have been allocated on the received subcarriers and symbols comprising encoded data bits protected by lower number of parity check equations have been allocated on the subcarriers that were truncated, to determine which subcarriers of the received multicarrier signal have been truncated, the number of truncated subcarriers relative to the total number of subcarriers used in the data transmission being substantially fixed, to obtain the symbols from non-truncated subcarriers, to obtain information on the allocation of the symbols to the subcarriers, to order the symbols on the basis of the obtained information, to remove mapping of the ordered symbols, thereby obtaining encoded data bits, and to decode the encoded data bits by determining bit values of symbols allocated to the truncated subcarriers from the encoded bits allocated to the non-truncated subcarriers. 18. The apparatus of claim 17, wherein the processing unit is further configured to calculate a noise variance from a frequency band of one or more subcarriers not carrying a symbol and suppress noise from the received multicarrier signal on the basis of the calculated noise variance. 19. The apparatus of claim 17, wherein the processing unit is further configured to determine the truncated subcarriers from the obtained channel state information. 20. The apparatus of claim 17, wherein the processing unit is further configured to obtain the information on the allocation of the symbols to the subcarriers from the obtained channel state information. 21. A multicarrier wireless communication system, comprising: a radio transmitter comprising a communication interface to provide a radio communication connection with at least one radio receiver, and a processing unit configured to obtain channel state information describing attenuation effected by a radio channel to subcarriers the radio transmitter uses in data transmission, encode different portions of a plurality of data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit, map encoded data bits to symbols, allocate the symbols to subcarriers on the basis of the channel state information and the degree of encoded bits associated with each symbol, determine, on the basis of the channel state information, a number of subcarriers to be truncated due to high attenuation, the number of subcarriers to be truncated relative to the total number of subcarriers used in the data transmission being substantially fixed, allocate symbols comprising encoded data bits protected by higher number of parity check equations on subcarriers that are determined not to be truncated and allocate symbols comprising encoded data bits protected by lower number of parity check equations on subcarriers determined to be truncated, truncate the determined subcarriers and symbols on the determined subcarriers, allocate the available transmit power to the non-truncated subcarriers, and control the radio transmitter to transmit, through the communication interface, a multicarrier signal comprising the symbols on the non-truncated subcarriers, anda radio receiver comprising a communication interface to provide a radio communication connection with the radio transmitter, and a processing unit configured to obtain channel state information describing attenuation effected by a radio channel to subcarriers the radio transmitter uses in data transmission, transmit the channel state information to the radio transmitter through the communication interface of the radio receiver, receive a multicarrier signal comprising a plurality of subcarriers carrying symbols through the communication interface, determine which subcarriers of the received multicarrier signal have been truncated, the number of truncated subcarriers relative to the total number of subcarriers used in the data transmission being substantially fixed, obtain the symbols from non-truncated subcarriers, obtain information on the allocation of the symbols to the subcarriers, order the symbols on the basis of the obtained information, remove mapping of the ordered symbols, thereby obtaining encoded data bits, and decode the encoded data bits by determining bit values of symbols allocated to the truncated subcarriers from the encoded bits allocated to the non-truncated subcarriers. 22. A computer readable non-transitory medium encoding a computer program of instructions for executing a computer process for data transmission in a radio transmitter of a multicarrier wireless communication system, the process comprising: obtaining channel state information describing attenuation effected by a radio channel to subcarriers used in the data transmission;encoding different portions of a plurality of data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit;mapping encoded data bits to symbols;allocating the symbols to subcarriers on the basis of the channel state information and the degree of encoded bits associated with each symbol;determining, on the basis of the channel state information, a number of subcarriers to be truncated due to high attenuation, the number of subcarriers to be truncated relative to the total number of subcarriers being substantially fixed;allocating symbols comprising encoded data bits protected by higher number of parity check equations on the subcarriers that are not determined to be truncated and allocating symbols comprising encoded data bits protected by lower number of parity check equations on the subcarriers that are determined to be truncated;truncating the determined subcarriers and symbols on the determined subcarriers;allocating the available transmit power to the non-truncated subcarriers, and controlling the radio transmitter to transmit a multicarrier signal comprising symbols on the non-truncated subcarriers. 23. The computer medium of claim 22, the medium including at least one of the following media: a computer readable medium, a program storage medium, a record medium, and a computer readable memory.
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