| 摘要 |
A method of operating a radio communication system uses orthogonal signals f or transmission of packets of data between two or more stations. In the transmitter data is encoded (204, 206, 208) onto a plurality of orthogonal carriers by a differential phase modulation technique, for example DQPSK. The carriers are combined into a single signal by an inverse discrete Fourier transform (210) and clipped at a predetermined amplitude (212) before being transmitted (218) to reduce the crest factor of the transmitted signal. The phase of one or more of the carriers is randomised before each data packet, hence a different crest factor will result for retransmissions of the same packet. This ensures that if a packet is difficult to transmit, because of reduced signal to noise ratio caused by clipping, it will retransmit successfully.
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