• Shared Channel Operation
• CDS (Channel Dependent Scheduling)
–Requires Channel Quality Information (CQI) sent on the UL
–Requires Pre-coding and Rank information sent on the UL for MIMO
• AMC (Adaptive Modulation and Coding)
–Requires informing the UE about allocated Resources
–Requires informing the UE about Modulation and Coding Schemes (MCS)
• HARQ (Hybrid ARQ)
–Uses Asynchronous adaptive retransmissions
–Uses Synchronous ACK/NAKs
–Requires ACK/NAK sent on the UL
• DL Modulation: QPSK, 16-QAM, 64-QAM
• Multiple Access Dimensions:
• DL Scheduler:
–Assigns Time/Frequency resources, rather than Time/Code resources
–May coordinate with neighbor Base Stations for interference management.
• DL Reference Signals (Pilots):
–Have fixed time duration and frequency sub-band allocations.
• ARQ runs at E-NodeB
–ARQ architecture is conceptually similar to HSPA. (It supports TM, UM, and
AM modes and retransmissions are based on status reports.)
–Optional HARQ assisted ARQ operation is possible in LTE.
• Multiple PDSCH Tx Modes
- Requires different Channel Quality Reporting, acknowledging and
scheduling mechanisms
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