Christer Edholm

System performance of WCDMA enhanced uplink

We present the potential performance improvements attainable by new enhancements to the WCDMA uplink. Improvements can be expected in both system capacity and end-user perceived performance. In this paper we focus on the capacity gains of short TTI, hybrid ARQ and scheduling in node-B. The performance is studied from both the link-level and system-level perspectives. The link performance results focus on the gains obtained by the introduction of short TTI and hybrid ARQ with soft combining in node-B. In the system performance results, we also evaluate node-B based rate scheduling for both 2 ms TTI and 10 ms TTL. Our studies indicate that with the introduction of enhanced uplink the gain in uplink capacity can be in the order of 70-100%.

High-data-rate availability in WCDMA enhanced uplink systems

The Wideband Code-Division Multiple-Access (WCDMA) standard has been evolved to further improve uplink high-data-rate coverage and to reduce delays. These enhancements are achieved by the use of fast scheduling, shorter transmission time interval and fast hybrid ARQ with soft combining. It has been shown that the use of high-data-rate radio access bearers is key to end-to-end uplink packet access performance [1]. In this paper, we study data rate availability in WCDMA Enhanced Uplink systems. Data rate availability as limited by user terminal power or own-signal interference in dispersive channels is investigated. We show that in dispersive channels the use of advanced receivers can further increase the availability of high data rates. Our results indicate that advanced receivers allow good availability of high-speed data access in dispersive channels.