4 Background and introduction

25.3193GPPEnhanced uplinkOverall descriptionStage 2TS

The technical purpose of the Enhanced Uplink feature is to improve the performance of uplink dedicated and common (FDD and 1.28Mcps TDD only) transport channels, i.e. to increase capacity and throughput and reduce delay. This is applicable for UTRA TDD and FDD.

The following techniques are part of the Enhanced Uplink feature:

– Node B controlled scheduling: possibility for the Node B to control, within the limits set by the RNC, the set of TFCs from which the UE may choose a suitable TFC.

– Node B controlled physical resource scheduling (TDD ony).

– Hybrid ARQ: rapid retransmissions of erroneously received data packets between UE and Node B.

– Higher order modulation (16QAM) (TDD and FDD).

– Higher order modulation (64QAM) (FDD only).

– Intra-frame code hopping (3.84 Mcps and 7.68 Mcps TDD only).

– Shorter TTI: possibility of introducing a 2 ms TTI (FDD only).

– Enhanced Uplink in CELL_FACH state and Idle mode (FDD and 1.28Mcps TDD only).

– Dual Cell E-DCH (FDD).

– Multi-Carrier E-DCH (1.28 Mcps TDD only).

– Uplink Transmit Diversity (FDD).

– Uplink MIMO (FDD only).

– Serving E-DCH cell decoupling (FDD only).