Abstract: In one embodiment, a receiver comprises an automatic gain controller (AGC), an equalizer, a controller, and a register interface. The AGC makes gain adjustments to compensate for changes in the average amplitude of a received signal. The equalizer has a coefficient updater that calculates coefficients and a finite impulse response (FIR) filter that applies the coefficients to the received signal to generate an equalized signal. During gain adjustments by the AGC, the register interface provides a weight freeze signal to the coefficient updater, which subsequently freezes the updating of the coefficients for a freeze duration period. Then, register interface provides a scaling factor, generated by the controller based on the size of the gain adjustment, to the coefficient updater. At the end of the freeze period, coefficient updater applies the scaling factor to the coefficients and unfreezes the coefficient updating.

Abstract: In one embodiment, a receiver has a reference generator and a main equalizer. The reference generator equalizes a received signal using one or more pilot reference signals. Then, the reference generator decodes one or more predetermined data channels of the equalized signal, makes hard decisions on the data of each decoded channel, and regenerates the original coding sequence of each decoded channel. The main equalizer uses each re-encoded channel as an additional reference signal along with one or more pilot signals to equalize a time-delayed version of the received signal. In alternative embodiments, the receiver might also have a step-size generator which selects optimum step sizes from a look-up table based on the number of re-encoded channels and the power of those channels. The step size is then used by the main equalizer along with the re-encoded channels to equalize the time-delayed received signal.

Abstract: In one embodiment, a receiver has a reference generator and a main equalizer. The reference generator equalizes a received signal using one or more pilot reference signals. Then, the reference generator decodes one or more predetermined data channels of the equalized signal, makes hard decisions on the data of each decoded channel, and regenerates the original coding sequence of each decoded channel. The main equalizer uses each re-encoded channel as an additional reference signal along with one or more pilot signals to equalize a time-delayed version of the received signal. In alternative embodiments, the receiver might also have a step-size generator which selects optimum step sizes from a look-up table based on the number of re-encoded channels and the power of those channels. The step size is then used by the main equalizer along with the re-encoded channels to equalize the time-delayed received signal.

Abstract: In one embodiment, a receiver has a reference generator and a main equalizer. The reference generator equalizes a received signal using one or more pilot reference signals. Then, the reference generator decodes one or more predetermined data channels of the equalized signal, makes hard decisions on the data of each decoded channel, and regenerates the original coding sequence of each decoded channel. The main equalizer uses each re-encoded channel as an additional reference signal along with one or more pilot signals to equalize a time-delayed version of the received signal. In alternative embodiments, the receiver might also have a step-size generator which selects optimum step sizes from a look-up table based on the number of re-encoded channels and the power of those channels. The step size is then used by the main equalizer along with the re-encoded channels to equalize the time-delayed received signal.

Abstract: In one embodiment, an HSDPA co-processor for 3GPP Release 6 Category 8 (7.2 Mb/s) HSDPA that provides all chip-rate, symbol-rate, physical-channel, and transport-channel processing for HSDPA in 90 nm CMOS. The co-processor design is scalable to all HSDPA data rates up to 14 Mb/s. The coprocessor implements an Advanced Receiver based on an NLMS equalizer, supports RX diversity and TX diversity, and provides up to 6.4 dB better performance than a typical single-antenna rake receiver. Thus, 3GPP R6 HSDPA functionality can be added to a legacy R99 modem using an HSDPA co-processor consistent with embodiments of the present invention, at a reasonable incremental cost and power.

Abstract: Methods and apparatus are provided for non-linear scaling of log likelihood ratio (LLR) values in a decoder. A decoder according to the present invention processes a received signal by generating a plurality of log-likelihood ratios having a first resolution; applying a non-linear function to the plurality of log-likelihood ratios to generate a plurality of log-likelihood ratios having a lower resolution; and applying the plurality of log-likelihood ratios having a lower resolution to a decoder. The non-linear function can distribute the log-likelihood ratios, for example, such that the frequency of each LLR value is more uniform than a linear scaling.

Abstract: In one embodiment, a receiver comprises an automatic gain controller (AGC), an equalizer, a controller, and a register interface. The AGC makes gain adjustments to compensate for changes in the average amplitude of a received signal. The equalizer has a coefficient updater that calculates coefficients and a finite impulse response (FIR) filter that applies the coefficients to the received signal to generate an equalized signal. During gain adjustments by the AGC, the register interface provides a weight freeze signal to the coefficient updater, which subsequently freezes the updating of the coefficients for a freeze duration period. Then, register interface provides a scaling factor, generated by the controller based on the size of the gain adjustment, to the coefficient updater. At the end of the freeze period, coefficient updater applies the scaling factor to the coefficients and unfreezes the coefficient updating.

Abstract: In one embodiment, a receiver has a reference generator and a main equalizer. The reference generator equalizes a received signal using one or more pilot reference signals. Then, the reference generator decodes one or more predetermined data channels of the equalized signal, makes hard decisions on the data of each decoded channel, and regenerates the original coding sequence of each decoded channel. The main equalizer uses each re-encoded channel as an additional reference signal along with one or more pilot signals to equalize a time-delayed version of the received signal. In alternative embodiments, the receiver might also have a step-size generator which selects optimum step sizes from a look-up table based on the number of re-encoded channels and the power of those channels. The step size is then used by the main equalizer along with the re-encoded channels to equalize the time-delayed received signal.

Abstract: In one embodiment, a receiver has a main equalizer and an auxiliary equalizer. The auxiliary equalizer equalizes a received signal using adaptively generated sets of auxiliary filter coefficients. Each set is generated by 1) filtering a received signal to generate an equalized signal, 2) calculating an error based on the equalized signal, and 3) calculating the set of coefficients based on the error and the prior set of auxiliary filter coefficients. The main equalizer equalizes a delayed version of the input signal by first applying a set of auxiliary filter coefficients, copied from the auxiliary equalizer, to the delayed version. Then, the main equalizer continues to equalize the delayed signal using main filter coefficients that are adaptively generated in a manner analogous to that of the auxiliary equalizer. In other embodiments, the number of sets of auxiliary filter coefficients and the period in which the sets are copied may vary.

Abstract: Methods and apparatus are provided for non-linear scaling of log likelihood ratio (LLR) values in a decoder. A decoder according to the present invention processes a received signal by generating a plurality of log-likelihood ratios having a first resolution; applying a non-linear function to the plurality of log-likelihood ratios to generate a plurality of log-likelihood ratios having a lower resolution; and applying the plurality of log-likelihood ratios having a lower resolution to a decoder. The non-linear function can distribute the log-likelihood ratios, for example, such that the frequency of each LLR value is more uniform than a linear scaling.