SIGNALING USING PHASE ROTATION TECHNIQUES IN A DIGITAL COMMUNICATIONS SYSTEM

In a telecommunications system, such as a cellular radio telecommunication s system, transmission information, such as modulation scheme selection information, coding information or power level control commands, is efficiently conveyed from the transmitter to the receiver without increasing the bandwidth requirements an d without introducing additional transmission delays. This can be accomplished by employing a data symbol phase rotation technique, wherein a sequence of data symbols, fo r example, a sequence of training symbols used for estimating the propagation characteristics of a given channel, are phase-rotated in accordance with a phase rotation factor that uniquely corresponds to the information being conveyed to the receiver. At the receiver, the symbols are de-rotated until the receiver recovers the training sequence. This allows the receiver to determine the phase rotation factor us ed to rotate the symbols at the transmitter. This, in turn, identifies the corresponding transmission information.