The present document is the technical report for the Release 8 Study Item "Synchronised E-DCH" (see [1]). This document is intended to gather all information in order to compare gains vs. complexity, and draw a conclusion on way forward. The document will describe likely impacts to the UTRA FDD specifications and system operation, estimate any changes to the UTRA FDD uplink data or control channel structure (including downlink control channels relating to the uplink and uplink control channels relating to the downlink) and evaluate potential performance gains This activity involves the Radio Access work area of the 3GPP studies and has impacts both on the Mobile Equipment and Access Network of the 3GPP systems.

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DPCCH DPDCH E-DCH E-DPCCH E-DPDCH HARQ HS-DPCCH HSUPA OVSF SHO TFC UTRA FDD

At 3GPP TSG RAN#37, a Study Item on "Synchronised E-DCH" was approved. The aim of the study item was to examine the use of synchronisation & OVSF codes for improving the orthogonality of the UTRA FDD uplink. Synchronised E-DCH users would implement timing advance sufficient to ensure that the reception timings of the main receive paths are synchronised at chip and TTI level. Furthermore, synchronised E-DCH users may share a common scrambling code and be separated using OVSF codes that are allocated on a dynamic basis by a modified HSUPA scheduler. Thus, orthogonality between users can be improved in the code domain or achieved by time domain separation. The Synchronised E-DCH physical and transport channel design should aim to maintain commonality with Release 7 HSUPA. HARQ should be supported. The study is similar to the Release 5 "Uplink Synchronous Transmission Scheme" [2]. However since Release 5, new features such as basestation scheduling and shorter TTI have been introduced and can act as enablers for OVSF domain scheduling. The study item examined the impacts to the specification, the required signalling and the performance of the synchronised E-DCH in the context of HSDPA & HSUPA. Three main proposals were studied:

• CDM based Synchronised E-DCH, in which time and OVSF multiplexing was assumed
• TDM based Synchronised E-DCH, in which pure TDM between users was assumed
• Interference cancellation algorithms, acting on the existing Release 7 HSUPA and also on the CDM and TDM proposals

In the TR, these proposals are referred to as the "CDM proposal", "TDM proposal" and "Interference Cancellation proposal"