A/sup 2/IR: an asynchronous and adaptive hybrid ARQ scheme for 3G evolution

An expanded effort is underway to support the evolution of the UMTS and cdma2000-1x standards to meet the rapidly developing needs associated with wireless Internet applications. The support of packet-switched high-speed data users is provided by means of a shared channel that can serve one packet data user at a time in a time-multiplexed manner. A number of performance enhancing technologies are proposed to ensure high peak and average packet data rates while supporting circuit switched voice and packet data on the same spectrum. These techniques include adaptive modulation and coding (AMC), hybrid ARQ (HARQ), fat-pipe scheduling, fast cell site selection (FCSS) and multiple input multiple output (MIMO) antenna techniques. In this paper, we provide description and simulation results for the asynchronous and adaptive HARQ scheme that is being considered for 3G evolution.