Abstract: This article introduces a novel duplex transmission technique-asymmetric frequency division duplex (AFDD). One of the characteristics in future mobile systems is asymmetric characteristic caused by service requirement and electromagnetic radiation, AFDD is designed to adapt to the new asymmetric characteristics. The AFDD puts forward a novel adaptive frequency-allocation scheme in downlink and uplink. Combining AFDD with code division multiple access (CDMA) communication system, it is proven that AFDD improves the capacity and coverage of the system compare with FDD CDMA system.

Key words: asymmetric characteristics;AFDD;Duplex;Mobile communications