Auto calibration with training sequences for wireless local loop at 26 GHz

Quadrature signal processing is widely used in current communication receivers. However, all inphase/quadrature (I/Q) processing receiver structures face a common problem of matching the amplitudes and phases of the inphase and the quadrature branches. This article proposes an auto calibration method, for I/Q imbalance compensation using base band digital processing on training sequences transmitted with data bursts of a test platform for a wireless local loop at 26 GHz. After a description of the test platform, a calibration method is proposed and its influence on the improvement of the transmission's performance, in term of phase constellation diagram and bit-error rate, presented.