摘要:
A method and apparatus for improved offset frequency estimation includes in a first embodiment a receiver (100) for coherent reception of a signal having known reference information, the receiver including an extractor (106) for extracting the reference information (107) from the signal, and an offset frequency estimator (110). The offset frequency estimator (110) includes a filter (121) for filtering the reference information and outputting a filtered reference sequence; a correlator (122, 124) for correlating the filtered reference sequence against a predetermined reference signal to form correlation values; and a peak detector (126) for determining an offset frequency estimate (131) from the correlation values. Other embodiments are also shown.
摘要:
A method and apparatus is provided to facilitate coherent communication in a random access channel. In encoding, reference symbols are inserted into a stream of access channel message data symbols and appended to a synchronization message to form a reference coded access channel transmission. Subsequently, the access channel transmission is prepared for transmission over a communication channel by being spread with a spreading code. In decoding, a known synchronization sequence is correlated with a received communication signal to generate a correlation peak when a synchronization message is present. The received communication signal is despread with a spreading code to derive a stream of reference samples and data samples. A channel response is determined from the correlation peak and revised based on estimates derived from the stream of reference samples. Finally, an estimated data symbol is detected from the stream of data samples by utilizing the revised channel response.
摘要:
A method (300) for adaptively adjusting weighting coefficients (188, 190, 192) in a code division multiple access (CDMA) radio receiver (100). A representation (172) of a desired RF signal (166) is received (108, 124, 127). A plurality of pilot signals (178, 182, 186) are generated responsive to the representation (172) of a desired RF signal (166). Each of a plurality of weighting coefficients (188, 190, 192) is determined responsive to more than one of the plurality of pilot signals (178, 182, 186).
摘要:
A method (250) determines weighting coefficients (188, 190, 192) in a code division multiple access (CDMA) radio receiver (100). A representation (172) of a desired RF signal (166) is received (108, 124, 127). A plurality of data signals (176, 180, 184) are generated responsive to the representation (172) of a desired RF signal (166). A plurality of pilot signals (178, 182, 186) are generated responsive to the first representation (172) of a desired RF signal (166). A total received signal power (174) is measured (128). A plurality of weighting coefficients (188, 190, 192) are determined responsive to the plurality of data signals (176, 180, 184), the plurality of pilot signals (178, 182, 186) and the total received signal power (174).
摘要:
A method and apparatus is provided for facilitating coherent communication reception. A received reference symbol coded spread spectrum communication signal is despread with a spreading code to derive a stream of reference samples and a stream of data samples. The channel response is estimated by utilizing the stream of reference samples. An offset frequency detector determines an offset to be applied to the received signal via a frequency locked loop, while a timing control compensates for slow timing drift and fast fading based on power estimates derived from the stream of reference samples and/or the stream of data samples. A slot detector controls gates which optimize the timing control and frequency offset detector outputs from the various timing branches. Thus an improved detection of estimated data symbols from the stream of received data samples is provided.
摘要:
The power of a received signal is measured at a base station. This measured power is used to predict a future power level of the received signal and from that to determine the appropriate power adjustment command. The power adjustment command is then sent to the transceiver.
摘要:
The method includes acquiring a signal (501); inputting (502), at a first time, a received symbol to a demodulator having a plurality of outputs to produce a set of early outputs; inputting (504), at a second time, the received symbol to the demodulator to produce a set of on-time outputs; inputting (505), at a third time, the received symbol to the demodulator to produce a set of late outputs; and comparing (506) at least one output in the set of early outputs with at least one output in the set of late outputs to produce a timing measure.
摘要:
A receiver (200, 400) implements improved channel estimation. The receiver (200, 400) demodulates a transmitted signal, and makes an initial channel estimate (115). The receiver (200, 400) then makes a hard decision (301) as to whether the channel estimate was correct and groups samples representing the decision. A vector sum of the group of samples is computed (302), and each sample is compared to the vector sum (303). The sample having the largest projection on the vector sum is retained (304), and the other samples are considered noise, and are thus discarded (305). After obtaining a predetermined number of retained samples (306), the retained samples are used to generate an new channel estimate (226). Since the noisy estimates are discarded, the new channel estimate (226) contains fewer errors than the initial channel estimate (115). The new channel estimate (226) is used to generate decoded data (250).
摘要:
A method and apparatus is provided for facilitating coherent communication reception. A received reference symbol coded spread spectrum communication signal is despread with a spreading code to derive a stream of reference samples and a stream of data samples. The channel response is estimated by utilizing the stream of reference samples. An offset frequency detector determines an offset to be applied to the received signal via a frequency locked loop, while a timing control compensates for slow timing drift and fast fading based on power estimates derived from the stream of reference samples and/or the stream of data samples. A rate estimator determines the rate at which the information was encoded, and the rate information is used to optimize the timing control, frequency offset detector and channel estimator. Thus an improved detection of estimated data symbols from the stream of received data samples is provided.
摘要:
Systems and methodologies are described that facilitate monitoring RF channels in a wireless communication environment to determine whether one or more channels comprise a forward-link-only (FLO) signal. A receiver can receive a first RF channel with a FLO signal and can monitor other RF channels for FLO signals. Upon a determination that a monitored RF channel comprises a FLO signal, the receiver can switch between the first RF channel and the monitored RF channel, employing information on current MLC decoding status, to facilitate providing seamless reception of the FLO signal, which can be superframe synchronized between RF channels. FLO signal detection can be performed using one or more of a wide-area identification channel energy detection protocol and a wide-area overhead information symbol decoding error detection protocol.