公开(公告)号：EP1836821A2

公开(公告)日：2007-09-26

申请号：EP06718127.1

申请日：2006-01-11

申请人： QUALCOMM INCORPORATED

发明人： COLLINS, Bruce ,  KRISHNAMURTHI, Rajeev ,  CHARI, Murali Ramaswamy ,  GAUTAM, Shusheel ,  VIJAYAN, Rajiv ,  CHUNG, Seong Taek

IPC分类号： H04L27/34

CPC分类号： H04L1/0065 ,  H04L1/0041 ,  H04L1/0045 ,  H04L1/0058 ,  H04L5/023 ,  H04L27/3488 ,  H04L2001/0098

摘要： A media access control (MAC) layer controller can manage base layer data and enhancement layer data in a layered modulation system. The MAC layer controller can process both base layer data and enhancement layer data and map the encoded symbols to a layered modulation constellation when both are present. If data for one of the layers terminates, then the MAC layer controller can generate and supply predetermined stuffing data to the layer lacking additional data. The MAC layer controller can send a control signal to the physical layer hardware to cause the hardware to map the layered signals having the stuffing data to a modified signal constellation. The MAC controller can also generate an overhead message that indicates the occurrence of the stuffing data. The receiver can receive the overhead message and can use the information to configure the receiver for the layered modulation constellation or the modified signal constellation.

公开(公告)号：EP1836822B1

公开(公告)日：2008-12-24

申请号：EP06718371.5

申请日：2006-01-11

申请人： QUALCOMM INCORPORATED

发明人： LING, Fuyun ,  CHUNG, Seong Taek ,  SUN, Thomas ,  BAI, Jinxia

IPC分类号： H04L27/34

CPC分类号： H04L25/067 ,  H04L25/03171 ,  H04L27/2601 ,  H04L27/3488 ,  H04L27/38 ,  H04L2025/0342

公开(公告)号：EP1864461A1

公开(公告)日：2007-12-12

申请号：EP06740334.5

申请日：2006-03-31

申请人： QUALCOMM INCORPORATED

发明人： WALKER, Kent G. ,  VIJAYAN, Rajiv ,  LING, Fuyun ,  CHUNG, Seong Taek ,  CHARI, Murali Ramaswamy

IPC分类号： H04L27/34

CPC分类号： H04L27/3488 ,  H04W52/0245 ,  Y02D70/00

摘要： A wireless communication apparatus in a hierarchically coded modulation system can use error control mechanisms generated during decoding of base layer information to predict a probability of successful demodulation of enhancement layer information. Performance in the demodulation of the base layer correlates to performance in the demodulation of the enhancement layer. The receiver can determine whether to attempt demodulation of temporally correlated enhancement layer data based in part on the predicted probability of success. If the receiver determines not to demodulate the enhancement layer, the receiver can power down the enhancement layer demodulator, or otherwise minimize the power expended in the enhancement layer demodulator.

公开(公告)号：EP1869767A2

公开(公告)日：2007-12-26

申请号：EP06738527.8

申请日：2006-03-13

申请人： Qualcomm Incorporated

发明人： MURTHY, Vinay ,  GUPTA, Alok ,  CHUNG, Seong Taek ,  LING, Fuyun

IPC分类号： H03J7/04

CPC分类号： G06F1/0353 ,  H04L5/0007 ,  H04L5/0048 ,  H04L27/2659 ,  H04L27/266 ,  H04L27/2662 ,  H04L27/2675 ,  H04L27/2678

摘要： Techniques for performing frequency control in an OFDM system are described. In one aspect, frequency acquisition is performed based on a received pilot, and frequency tracking is performed based on received OFDM symbols. For frequency acquisition, an initial frequency error estimate may be derived based on the received pilot, and an automatic frequency control (AFC) loop may be initialized with the initial frequency error estimate. For frequency tracking, a frequency error estimate may be derived for each received OFDM symbol, and the AFC loop may be updated with the frequency error estimate. Frequency error in input samples is corrected by the AFC loop with the initial frequency error estimate as well as the frequency error estimate for each received OFDM symbol. In another aspect, a variable number of samples of a received OFDM symbol are selected, e.g., based on the received OFDM symbol timing, for use for frequency error estimation.

公开(公告)号：EP1836822A1

公开(公告)日：2007-09-26

申请号：EP06718371.5

申请日：2006-01-11

申请人： QUALCOMM INCORPORATED

发明人： LING, Fuyun ,  CHUNG, Seong Taek ,  SUN, Thomas ,  BAI, Jinxia

IPC分类号： H04L27/34

CPC分类号： H04L25/067 ,  H04L25/03171 ,  H04L27/2601 ,  H04L27/3488 ,  H04L27/38 ,  H04L2025/0342

摘要： A system and method are provided for generating bit log likelihood ratio (LLR) values for two-layered Quadrature Phase-Shift Keying (QPSK) turbo decoding in a wireless communications user terminal (UT). The method includes receiving a two-layered QPSK signal with an energy ratio that is unknown, but typically defined as either k12 or k22. The method selects a mismatched energy ratio (k2) between k12 and k22, and generating bit LLR values for two-layered QPSK turbo decoding, using the mismatched k2 energy ratio. For example, if the received two-layered QPSK signal is known to have an energy ratio of about 4 or about 6.25. Then, k2 is selected to be about 5.0625. Alternately stated, the mismatched k2 energy ratio in selected by determining the approximate midpoint between k12 and k22.

公开(公告)号：EP1994704A1

公开(公告)日：2008-11-26

申请号：EP07758564.4

申请日：2007-03-14

申请人： QUALCOMM Incorporated

发明人： VRCELJ, Bojan ,  KRISHNAMOORTHI, Raghuraman ,  CHUNG, Seong Taek ,  LING, Fuyun

IPC分类号： H04L27/26

CPC分类号： H04L27/2657 ,  H04L27/2607 ,  H04L27/2665 ,  H04L27/2678 ,  H04L27/2695

摘要： A frequency tracking method and apparatus is provided. A receiver receives OFDM symbols and determines associated frequency offset. A frequency error estimator selects a cross correlation window for determining frequency offset based on timing offset. A symbol timing estimator is used to determine the timing offset.

公开(公告)号：EP1969795A1

公开(公告)日：2008-09-17

申请号：EP07701216.9

申请日：2007-01-08

申请人： QUALCOMM Incorporated

发明人： CHUNG, Seong Taek ,  MUKKAVILLI, Krishna, Kiran ,  MURTHY, Vinay ,  TIAN, Tao

IPC分类号： H04L27/26

CPC分类号： H04L27/2657 ,  H04L27/2675

摘要： Methods and apparatus for frequency tracking of a received signal. In an aspect, a method is provided wherein the received signal comprises one or more symbols having a periodic structure. The method comprises receiving a plurality of samples of a selected symbol that comprises pilot signals scrambled with data and determining a window size and a periodicity factor. The method also comprises accumulating a correlation between samples in a first window and samples in a second window to produce an accumulated correlation value, wherein the first and second windows have a size and a separation based on the window size and the periodicity factor, respectively, and deriving a frequency error estimate based on the accumulated correlation value.

公开(公告)号：EP1854212A1

公开(公告)日：2007-11-14

申请号：EP06736722.7

申请日：2006-03-01

申请人： QUALCOMM INCORPORATED

发明人： CHUNG, Seong Taek ,  GUPTA, Alok ,  LING, Fuyun ,  MURTHY, Vinay

IPC分类号： H03J7/04

CPC分类号： H03J7/04 ,  H03J1/0083

摘要： Techniques for performing frequency control using dual-loop automatic frequency control (AFC) are described. The dual-loop AFC includes an inner loop that corrects short-term frequency variations (e.g., due to Doppler effect) and an outer loop that corrects long-term frequency variations (e.g., due to component tolerances and temperature variations). In one design, a first inner loop is implemented for frequency control of a first system (e.g., a broadcast system), a second inner loop is implemented for frequency control of a second system (e.g., a cellular system), and at least one outer loop is implemented for adjusting a reference frequency used to receive the first and second systems. Each inner loop estimates and corrects the frequency error in an input signal for the associated system and may be enabled when receiving the system. The reference frequency may be used for frequency downconversion, sampling and/or other purposes.