Throughput Evaluation of Fixed Beams in a TD-SCDMA HSDPA System Using Different CQI Feedback Algorithms

In TD-SCDMA HSDPA user equipments (UEs) measure their own radio channel status and report the quality to the base station (Node B) using a channel quality indicator (CQI). The accuracy of the CQI has great impact on the scheduling and adaptive modulation coding (AMC) algorithms. There are not more than four shared feedback channels (HS-SICHs) per cell to report the CQI to Node B due to code dimension limitation. Consequently, time delay exists in the process of the CQI feedback. The impact of the time delay in CQI feedback process on the system throughput is analyzed. Furthermore, a novel CQI feedback algorithm aim to reduce the time delay is proposed. Extensive simulations studies are carried out to evaluate the throughput of fixed beam in a TD-SCDMA HSDPA system using different CQI feedback algorithms.