摘要:
Exemplary received signal processing may be based on maintaining a model of received signal impairment correlations, wherein each term of the model is updated periodically or as needed based on measuring impairments for a received signal of interest. An exemplary model comprises an interference impairment term scaled by a first model fitting parameter, and a noise impairment term scaled by a second model fitting parameters. The model terms may be maintained based on current channel estimates and delay information and may be fitted to measured impairment by adapting the model fitting parameters based on the measured impairment. The modeled received signal impairment correlations may be used to compute RAKE combining weights for received signal processing, or to compute Signal-to-Interference (SIR) estimates. Combined or separate models may be used for multiple received signals. As such, the exemplary modeling is extended to soft handoff, multiple antennas, and other diversity situations.
摘要:
Interference, such as inter-symbol interference, from a symbol of interest in a RAKE receiver is reduced. The RAKE receiver comprises a plurality of RAKE fingers, a processor, and a combiner. The plurality of RAKE fingers despread symbols received over multiple paths of a multi-path channel. The processor determines cross-correlations between symbol waveforms from different symbols and multiple paths. The combiner combines the despread symbols using the cross-correlations to reduce interference from the symbol of interest.
摘要:
Exemplary combining weight generation is based on estimating received signal impairment correlations using a weighted summation of interference impairment terms, such as an interference correlation matrix associated with a transmitting base station, and a noise impairment term, such as a noise correlation matrix, the impairment terms scaled by fitting parameters. The estimate is updated based on adapting the fitting parameters responsive to measured signal impairment correlations. The interference matrices are calculated from channel estimates and delay information, and knowledge of the receive filter pulse shape. Instantaneous values of the fitting parameters are determined by fitting the impairment correlation terms to impairment correlations measured at successive time instants and the fitting parameters are adapted at each time instant by updating the fitting parameters based on the instantaneous values.
摘要:
A method and apparatus for determining operating modes in a receiver is described herein. A delay searcher in the receiver detects a signal image in the received signal. When the receiver is a RAKE receiver, a plurality of RAKE fingers coherently combine time-shifted versions of the received signal at different delays. Alternatively, when the receiver is a chip equalization receiver, an FIR filter coherently pre-combines the signal images in the received signal. A processor determines delays. In particular, the processor generates a first signal quality metric for a single-delay receiver mode, and generates a second signal quality metric for a multi-delay receiver mode. Based on a comparison of the first and second signal quality metrics, the processor selects the single-delay or the multi-delay receiver mode for processing the signal image.
摘要:
A wireless communication receiver obtains improved performance under certain fast fading conditions by basing one or more received signal processing operations on pre-despreading chip sample correlations rather than on post-despreading noise correlations, but preserves soft scaling information by determining one or more scaling factors that relate the chip sample correlations to the noise correlations. By way of non-limiting examples, a Generalized RAKE receiver circuit may base combining weight generation on chip sample correlations rather than on post-despreading pilot symbol noise correlations, but scale the combining weights as a function of the one or more scaling factors, or, equivalently, scale the combined values generated from the combining weights. Similar scaling may be performed with respect to chip equalization filter combining weights in a chip equalization receiver circuit. Further, Signal-to-Interference Ratio (SIR) estimation may be improved in terms of fast fading responsiveness by using chip sample correlations, while preserving the proper scaling.
摘要:
A wireless communication device or system generates transmit power control feedback for a received power control channel by determining a command error rate (CER), or by identifying a target signal quality for the power control channel according to a defined signal-quality-to-CER mapping function. Generally, the power control channel does not include error-coded data to use for CER estimation. However, in one embodiment, the channel does include known reference bits that are evaluated for CER estimation, with the estimated CER used to set the signal quality target for inner loop power control. In other embodiments, a computed reception error probability is used to identify a CER estimate according to a defined probability-to-CER mapping function. By way of non-limiting example, these embodiments may be used to provide power control feedback for power control commands transmitted on a Fractional Dedicated Physical Channel in WCDMA systems.
摘要:
Signal impairment correlations for multiple signals in a received multipath signal are constructed by fitting parametric models associated with each high-data-rate signal in the multipath against measured impairment correlations. The estimated model fitting parameters are applied to form impairment correlation estimates for all signals. The models comprise a separate impairment covariance matrix scaled by a model fitting parameter for each high-data-rate signal and a noise covariance matrix scaled by a noise element model fitting parameter. The model fitting parameters may be estimated by a least-squares formulation and applied to form impairment correlation estimates for all signals of interest. The resulting impairment correlation estimates may be provided to G-RAKE receivers or joint scaling demodulators to demodulate the signals while suppressing interference from the high-data-rate signals.
摘要:
A method and apparatus in a radio receiver for canceling interference from a high power, high data rate signal received in a combined signal that includes a contribution from the high power signal and a contribution from a lower power signal. It is first determined whether the high power signal was correctly received. A CRC checksum may be used to determine whether the high power signal was received with a good reliability. Thereafter, the contribution of the high power signal is removed from the received signal only if the high power signal was correctly received. The contribution of the high power signal may be removed by hard-subtracting the contribution of the high power signal from the received signal if all of the bits of the checksum are correct, and soft-subtracting the contribution of the high power signal from the received signal if most, but not all, of the bits in the checksum are correct.
摘要:
A method and corresponding circuit for determining a final result for a desired series of multiply-and-accumulate (MAC) operations are based on counting the occurrence of products in the desired series of MAC operations, multiplying the counts by their corresponding products to obtain partial sums, and adding the partial sums to obtain the final result. MAC processing as taught herein can be applied to a wide range of applications, such as received signal processing in wireless communication for computationally efficient (and high-rate) generation of interference correlation estimates and/or equalization filter values for a received communication signal.
摘要:
Multi-transmitter interference caused by one or more interfering own-cell and/or other-cell transmitters is reduced in a RAKE-based receiver. The RAKE-based receiver comprises a plurality of RAKE fingers, a processor and a combiner. The plurality of RAKE fingers are configured to despread received symbols, wherein a delay for a first one of the plurality of RAKE fingers corresponds to a symbol of interest transmitted by a first transmitter and a delay for a second one of the plurality of RAKE fingers corresponds to an interfering symbol transmitted by a second transmitter. The processor is configured to determine a cross-correlation between the symbol of interest and the interfering symbol. The combiner is configured to combine the symbol of interest with the interfering symbol using the cross-correlation to reduce interference attributable to the interfering symbol from the symbol of interest.