Agere Systems Inc.

Xiao-Jiao Tao

Adriaan Kamerman

Tim Schenk

Allert Van Zelst

Isabella Modonesi

Yanling Sun

Jeroen C Kuenen

In a multiple-input, multiple-output (MIMO) system, a receiver is implemented with at least one additional receive path beyond the number of transmit antennas used to transmit the signals (e.g., wireless OFDM signals) received at the receiver. In one embodiment, the additional receive path is used to reduced co-channel interference (CCI) in the recovered OFDM signals. In particular, each receive path applies recursive filtering to generate separate subcarrier signals. A processor converts the separate subcarrier signals from the different receive paths into a first set of subcarrier signals corresponding to each transmitted OFDM signal, where each first set of subcarrier signals has desired signal and possibly CCI. The processor also generates a second set of subcarrier signals corresponding to the CCI. The processor subtracts portions of the second set of subcarrier signals from each first set of subcarrier signals to generate recovered OFDM signals having reduced CCI.

MIMO receivers having one or more additional receive paths

The present invention is directed to an adaptive phase controller employing a threshold level and a method of controlling a phase. In one embodiment, the adaptive phase controller includes a comparator configured to receive a comparison signal representing a phase and to provide a vernier signal based on comparing first and second samples of the comparison signal when the comparison signal is below the threshold level. Additionally, the adaptive phase controller also includes an adder/decoder coupled to the comparator and configured to adjust a current number corresponding to the phase based on the vernier signal.

Adaptive phase controller, method of controlling a phase and transmitter employing the same

The present invention is directed to a channel calibrator and a method of calibrating in-phase and quadrature phase channels for use with a quadrature mixing receiver. In one embodiment, the channel calibrator includes a balancer and an equalizer. The balancer reduces frequency dependent imbalance between an in-phase channel and a quadrature phase channel associated with the receiver. The equalizer decreases frequency independent mismatch between the in-phase channel and the quadrature phase channel.

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Losser, Netherlands

Xiao-Jiao Tao