The traffic with asymmetry between uplink and downlink has recently been getting remarkable on mobile communication systems providing multimedia communication services. In the future mobile communications, the accommodation of asymmetric traffic is essential to realize efficient multimedia mobile communication systems. This paper discusses asymmetric traffic accommodation in CDMA/FDD cellular packet communication systems and proposes its efficient scheme using an adaptive cell sizing technique. In the proposed scheme, each base station autonomously controls its coverage area so that almost the same communication quality can be achieved across the service area under the asymmetric traffic conditions. We present some numerical examples to demonstrate the effectiveness of the proposed scheme by using computer simulation. The simulation results show that, under asymmetric traffic conditions, the proposed scheme can provide fair communication quality across the service area in both links and can improve total transmission capacity in the uplink.

In this letter, we propose a robust IFDD scheme employing an interference canceller, which is used for mitigating interferences from the transmitting signal instead of complex filter bank to reduce the complexity, for the OFDM system using feedback information. According to simulation results, the proposed IFDD OFDM system does not show significant performance degradation but maintains the robustness against the fast time-varying multipath channel, while the TDD OFDM system estimating feedback information from receiving block makes serious performance degradation.