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Montage Technology (shanghai) Co., Ltd.

Ching-Yih Tseng

Wen-Sheng Cheng

This invention discloses apparatus and methods for detecting transmit symbols from the receiving waveform samples at the receiver side for communications systems. The receiving waveform samples are corrupted by channel and noise effects and the detection is carried out with a maximum likelihood optimality criterion. This invention utilizes a successive linear constraint exchange scheme that formulates a sequence of linearly constrained minimization subproblems to allow the solutions to these subproblems, combined with certain quantization and mapping operations, to converge to the optimal maximum likelihood estimate. This invention is applicable to any digitally modulated communications systems, including but not limited to Multiple Input Multiple Output (MIMO) communications systems.

Apparatus and methods for maximum likelihood symbol detection in communications systems

A system for reducing a mismatch between an in-phase (I) signal and a quadrature phase (Q) signal is disclosed. The system includes a phase compensation block comprising an infinite impulse response (IIR) filter configured to reduce a first portion of a mismatch between an I signal and a Q signal, wherein the first portion includes frequency selective phase mismatch. The system further includes a gain compensation block comprising a finite impulse response (FIR) filter configured to reduce a second portion of the mismatch, wherein the second portion includes frequency selective gain mismatch. The phase compensation block and the gain compensation block are calibrated at least in part based on a loopback signal, wherein the loopback signal is routed from a transmitting portion of a radio frequency (RF) circuitry back to a receiving portion of the RF circuitry.

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Milpitas, CA, United States of America

Ching-Yih Tseng