Reducing peak to average ratio of transmit signal by intentional phase rotating among composed signals

摘要

Apparatus for reducing power amplifier headroom in a wireless transmission system comprises an orthogonal modulation circuit (32,34) and a phase rotation circuit (70) coupled to the orthogonal modulation circuit. The orthogonal modulation circuit utilizes a Walsh code for modulating an in-phase signal and a quadrature signal. The orthogonal modulation circuit has an in-phase output (SI,K) and a quadrature output (SQ,K). The phase rotation circuit (70) rotates the phase of the in-phase signal and the quadrature signal, producing a phase rotated in-phase signal and a phase rotated quadrature signal. Multiple Walsh code defined channels are associated with a particular wireless user.