Design and Performance of Down Link Shared Control Channel for HSDPA

An expanded effort is underway to support the evolution of the UMTS standard to meet the rapidly developing needs associated with wireless Internet applications. The support of high-speed downlink packet access (HSDPA) is provided by means of a new, shared channel called HS-DSCH (High speed downlink shared channel) which is enabled by a number of performance enhancing techniques such as Adaptive modulation and coding 9AMC), Hybrid ARQ (HARQ), Fat-pipe scheduling, Fast cell site selection (FCSS) and Multiple input multiple output (MIMO) antenna techniques. To fully benefit from these techniques, one must guarantee fast and reliable control message exchange between the base station and the user terminals. The downlink signaling is done through the use of shared control channels (SCCH) accompanied with each HS-DSCH. Since the SCCHs, HS-DSCH, and voice channels share the same resources (power, bandwidth), improved control signaling often means reduced system capacity. In this paper, we evaluate the performance of the SCCH. The challenges and tradeoffs in the SCCH design will also be discussed.