| 摘要 |
A method is disclosed to distinguish a first type of control channel from a second type of control channel. The method includes steps of (a) transmitting a carrier of the first type of control channel so as to include a first symbol sequence that results, when demodulated, in a sine wave having a frequency with a first offset from the carrier; (b) transmitting a carrier of the second type of control channel so as to include a second symbol sequence that results, when demodulated, in a sine wave having a frequency with a second offset from the carrier; and (c) demodulating a received carrier and detecting whether the carrier includes the first type of control channel of the second type of control channel. In the preferred embodiment of this invention the first symbol sequence is an all zeroes sequence, and the second type of symbol sequence is an alternating ones and zeroes sequence, which results in the first offset being a positive offset, and the second offset being a negative offset. In a most preferred embodiment the first offset is +67.7 kHz, and the second offset is -67.7 kHz. The step of demodulating includes a step of multiplying an I/Q representation of the received symbol sequence by 1-j, -1j, 1-j,..., and by 1j, -1-j, 1j,...
|
