During the past few years, wireless and portable communication services have been increasing rapidly. As cellular telephony is evolving worldwide towards fully digital systems, the opportunity arises to apply the advanced digital data services to mobile users. Recently, some internet services are becoming available in cellular network and the pressure to integrate many services with the internet as seamlessly as possible increases. In contrast to wired links, wireless links have higher loss rate. So, the error control for data transmission on wireless links becomes more important for mobile data services. Basically, error control schemes can be divided into two categories: ARQ schemes and forward error correction schemes. ARQ is an error detection with retransmission scheme. The efficiency of wireless IP packet transmission system depends on ARQ schemes. There are several known ARQ methods such as stop-and-wait, go-back-N, and selective repeat. In this paper, two adaptive hybrid ARQ schemes are proposed for IP packet transmission. One is the modified scheme of SR(selective repeat)+MC(multicopy) ARQ[3] and the other is SR ARQ which is modified to operate adaptively according to the channel condition. Two schemes use one more received ACK information to operate adaptively according to the radio channel condition. Simulation results of these schemes show that proposed schemes improve the performance of radio ink control protocol in the case that internet web services are provided through the wireless fading channel.
