Abstract: An apparatus and method for receiving layered modulation signals is disclosed. A typical method includes receiving a layered modulation signal including an upper layer signal and a lower layer signal, demodulating and decoding the upper layer signal from the received layered modulation signal, estimating an upper layer amplitude factor and an upper layer phase factor from the received layered modulation signal. A substantially ideal upper layer signal is reconstructed from the demodulated and decoded upper layer signal including matching an ideal amplitude and an ideal phase by applying the upper layer amplitude factor and the upper layer phase factor to the reconstructed ideal upper layer signal. Finally, the reconstructed ideal upper layer signal is subtracted from the received layered modulation signal to produce the lower layer signal for processing.

Abstract: The present invention provides apparatus and method for calibrating I/Q imbalance in a direct conversion transmitter-receiver, including generating a complex sinusoidal signal with a center frequency at ?i, sending the sinusoidal signal to the receiver and using FFT to estimate the I/Q the phase ?, the gain imbalance ?, and phase imbalance ?. The input signal is calibrated according to the estimated I/Q amplitude and phase imbalance.

Abstract: An apparatus and method for receiving layered modulation signals is disclosed. A typical method includes receiving a layered modulation signal including an upper layer signal and a lower layer signal, demodulating and decoding the upper layer signal from the received layered modulation signal, estimating an upper layer amplitude factor and an upper layer phase factor from the received layered modulation signal. A substantially ideal upper layer signal is reconstructed from the demodulated and decoded upper layer signal including matching an ideal amplitude and an ideal phase by applying the upper layer amplitude factor and the upper layer phase factor to the reconstructed ideal upper layer signal. Finally, the reconstructed ideal upper layer signal is subtracted from the received layered modulation signal to produce the lower layer signal for processing.

Abstract: Various approaches for forming more accurate location estimates are disclosed. In some approaches, a plurality of preliminary location estimates are formed based on subsets of time-of-arrival measurements. A final location estimate is then made based on the preliminary location estimates. In other approaches, a quality indicator associated with the time-of-arrival measurements is modified, and subsequently used in a location algorithm. Optionally, multiple approaches may be used together.

Abstract: Various approaches for forming more accurate location estimates are disclosed. In some approaches, a plurality of preliminary location estimates are formed based on subsets of time-of-arrival measurements. A final location estimate is then made based on the preliminary location estimates. In other approaches, a quality indicator associated with the time-of-arrival measurements is modified, and subsequently used in a location algorithm. Optionally, multiple approaches may be used together.