Performance and modeling of WCDMA/HSDPA transmission/H-ARQ schemes

As part of 3GPP Release´5 standardization work on WCDMA/UTRA, a new packet concept has been added to grant high speed downlink packet access (HSDPA). One of the central features of the HSDPA concept is advanced physical layer retransmission scheduling employing soft combining gain, incremental redundancy, and low retransmission delays. Since the average retransmission probability in HSDPA is typically on the order of 10-40%, the retransmission scheduling needs to be accurately simulated and modeled at both link and network level. Based on an extensive simulation campaign, this paper presents methods to map the link level performance of the HSDPA retransmission schemes into a low-complexity representation suitable for network level evaluation. The method accurately predicts the throughput and delay performance within a few percent.