Abstract:
A detector in a mobile device receives input from a modem, determines whether the mobile device is indoor or outdoor based on the modem-supplied input, and stores in memory a binary value to indicate an indoor-outdoor state of the mobile device. In certain embodiments, the mobile device includes a modem of a cell phone and the modem-supplied input includes an estimate of a power delay profile. In some embodiments, the detector extracts a feature from the modem-supplied input, and uses the extracted feature with a classifier, to output a state and a probability of the state. In these embodiments, logic in the detector compares an empirically-determined threshold, against a probability output by the classifier, and when the threshold is exceeded, the state determined by the classifier is output as the state of the mobile device. In other embodiments, the classifier outputs the state of the mobile device directly (without probability).
Abstract:
In a method of estimating interference in a received signal, the method includes receiving a plurality of subcarriers (400) from a remote transmitter. Each of the subcarriers is multiplied by a control signal (406). At least two of the subcarriers are compared to produce a differential signal (408). Interference is estimated in response to the differential signal (410).
Abstract:
A receiver performs interference mitigation under blind or semi-blind conditions using diversity present in the signal of interest or in the interferer. A first path interference mitigation procedure extracts training information from received signals, performs interference mitigation on the training information and estimates the channel. The second path interference mitigation procedure uses data extracted from the received signal and the channel estimate to perform interference mitigation. Each interference mitigation process can take the form of a lossy compression followed by decompression.
Abstract:
A method of wireless communication is disclosed in the present invention, comprising: obtaining a first channel estimate of a first transmission from a cell; and correlating the first channel estimate with a second channel estimate of a second transmission from the cell, the second transmission and the first transmission are through correlated channels.
Abstract:
A mobile communication device to equalize a Doppler shifted received signal according to one embodiment is configured to: extract one or more pilot signals from a segment of the received signal; perform Minimum Mean Square Error (MMSE) filtering on the extracted pilot signals, wherein the filter provides estimated pilot signal impulse responses; estimate the amplitudes of one or more path components of the estimated pilot signal impulse responses; estimate the phases of one or more path components of the estimated pilot signal impulse responses; and combine the estimated amplitudes and the estimated phases of the path components of the pilot signal impulse responses, wherein the combination provides an estimated channel impulse response.
Abstract:
Certain aspects of the present disclosure relate to techniques and apparatus for enabling non-destaggered channel estimation. In aspects, a method for wireless communications is provided including determining a first channel impulse response (CIR) based on a first set of received reference signals staggered in time, determining a second CIR based on a second set of received reference signals from the same sub- frame time slot, wherein a reference signal is associated with one of a plurality of virtual transmit antenna ports, and aligning the first CIR and the second CIR based, at least in part, on a time tracking loop (TTL) timing offset.
Abstract:
Log-likelihood ratios produced by a decoder are incorporated into a soft symbol to soft bit estimation process and are used to perform improved channel estimation and impairment covariance estimation. In an example method, a plurality of soft bits and corresponding probability metrics for a series of received unknown symbols are generated. Estimates of the received unknown information symbols are then regenerated, as a function of the soft bits and corresponding probability metrics. An estimate of the average amplitude of the received unknown information symbols, or an estimate of the propagation channel response experienced by the received unknown information symbols, or both, are calculated, as a function of the regenerated symbol estimates. The results are applied to produce demodulated symbols for a second decoding iteration for the series of received unknown symbols.