Lucent Technologies Inc.

Steven P Nicoloso

R Michael Buehrer

Shang-Chieh Liu

Dirck Uptegrove

Robert Atmaram Soni

Sridhar Gollamudi

Mark David Hahm

A cellular communications system includes a base station and at least one mobile station communicating therewith. The base station may include a plurality of antennas and a modulator for providing a transmit signal for each antenna. The modulator may estimate a weighting factor for each transmit signal based upon considering each transmit signal as having an unknown and arbitrary fading factor associated therewith and based upon considering the unknown and arbitrary fading factors to have a predetermined cross-correlation function.

Cellular communications system and related methods

The method of channel estimation generates an initial channel estimate from a pilot signal in a received signal, and estimates the data in the received signal using the channel estimate. An updated channel estimate is then obtained from the estimated data. This process of estimating the data and re-estimating the channel estimate is reiterated a desired number of times to refine the accuracy of the channel estimate.

Iterative channel estimation and compensation based thereon

The method of channel estimation determines linear regression coefficients for N blocks of a first signal component in a received signal on a block-by-block basis, and determines a channel estimate based on the linear regression coefficients for the N blocks. Using the channel estimate, channel distortion in a second signal component of the received signal can be significantly eliminated.

Method of channel estimation and compensation based thereon

A multistage or parallel interference canceler (PIC) arrangement is disclosed for use in a communications system using code division multiple access (CDMA) with M-ary orthogonal modulation. All the M symbol waveforms, weighted according to their correlations with a despread signal, are combined to form a reconstructed symbol waveform for each user in each stage. The reconstructed symbol waveforms for all users are summed to form an estimated composite received signal having reduced interference which is subtracted from the composite received signal to generate a residual interference signal (RIS). While the total received signal is despread in the first stage of the PIC, the RIS or cancellation residue signal from the immediately preceding stage is used in succeeding stages of the PIC. A final decision is made by despreading the RIS from the final stage of the PIC, correlating it with the M symbol waveforms using an FHT. A weight vector from the final stage is then added to the output of the FHT. The real part or the squared magnitude of the resulting correlations, depending, respectively, on whether coherent or noncoherent demodulation is used, is then taken. The final symbol decision is made by selecting the symbol corresponding to the maximum component resulting decision statistic vector.

Multistage interference cancellation for CDMA applications using M-ary orthogonal moduation

The base station system includes a cancellation processor connected to a plurality of conventional signal processors. Under the control of a controller, the signal processors acquire user signals in signals received by the base station antennas. The controller controls the cancellation processor to perform cancellation operations with respect to the acquired user signals. The cancellation processor includes first-nth filter stages. Each filter stage operates in the same manner. A filter stage obtains, in parallel, the acquired user signals from signals supplied thereto by estimating symbols in the acquired user signals under the control of the controller. The cancellation processor also includes a cancellation stage associated with each filter stage. Each cancellation stage cancels, in parallel, the obtained user signals output from the associated filter stage from the signals received by the base station antennas. The resulting residual signals output from a cancellation stage are supplied to the next filter stage, and the signals supplied to the first filter stage are the signals received by the base station antennas. A cancellation stage cancels the obtained user signals received thereby from the received signals at a substantially same time with respect to the received signals.

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Parsippany, NJ, United States of America

Steven P Nicoloso