Abstract: Methods and apparatus to perform fractional-spaced channel estimation for frequency-domain equalizers in high-speed downlink packet access (HSDPA) receivers are disclosed. An example method comprises computing a first fractionally-spaced time-domain channel estimate from an oversampled CDMA signal, and computing a first chip-interval frequency-domain equalizer (FDE) coefficient from the first fractionally-spaced channel estimate.

Abstract: Methods and apparatus to perform noise estimation for frequency-domain equalizers of high-speed downlink packet access (HSDPA) receivers are disclosed. An example method comprises measuring a total power associated with a code division multiple access (CDMA) signal received through a plurality of multipaths, measuring a plurality of channel responses for respective ones of the plurality of multipaths, measuring a plurality of noise plus inter-path interference powers for the respective ones of the plurality of multipaths, and estimating an additive noise power for the received CDMA signal based on the total power, the plurality of channel responses and the plurality of noise plus inter-path interference powers.

Abstract: Methods and apparatus to perform closed-loop transmit diversity with frequency-domain equalizers in high-speed downlink packet access (HSDPA) receivers are disclosed. An example method comprises receiving a first signal representative of a first code division multiple access (CDMA) signal received from a first transmit antenna and a second signal representative of a second CDMA signal received from a second transmit antenna, computing a first channel estimate for a first path from the first transmit antenna to the receiver, computing a second channel estimate for a second path from the second transmit antenna to the receiver, and computing a frequency-domain equalizer (FDE) coefficient for the first path based on the first and the second channel estimates.