Coherent demodulation with decision-directed channel estimation for digital communication

摘要

Methods and apparatus for demodulating a received communication signal employing coherent demodulation and decision-directed channel estimation are disclosed that have a significant gain compared to a receiver employing noncoherent demodulation. This is particularly so for spread spectrum communication systems such as the uplink specified by the TIA/EIA/IS-95 mobile communication standard, in which an orthogonal modulation scheme combined with convolutional coding and interleaving is used. The coherent demodulation methods and apparatus do not require a pilot signal, and thus can be used in communication systems that are originally designed for use of noncoherent demodulation.