| 摘要 |
A method is disclosed for operating a wireless mobile station to receive a time slot sent through a radio channel from a transmitter. In a GPRS embodiment the time slot has a Header portion and a Data portion, wherein the Header portion contains information for specifying whether the Data portion is modulated using 8-PSK modulation or pi/4-shifted DQPSK modulation. When modulated using 8-PSK modulation, the Data portion includes a plurality of Pilot symbol sequences at predetermined locations. The method has steps of (a) estimating the quality of the radio channel using symbol sequences found at the predetermined locations, the symbol sequences being assumed to be Pilot symbol sequences; (b) determining a magnitude of a detection error between assumed transmitted Pilot symbol sequences and the detected symbols found at the predetermined locations; (c) calculating a mean of the detection error powers; (d) comparing the calculated mean of the detection error powers with a threshold value; and (e) selecting the modulation type of the Data portion as being one of 8-PSK or pi/4-shifted DQPSK based on the result of the step of comparing.
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