Requirements of HSPA • Data Rate – Demand for higher peak data rates • Delay – Lower latency • Capacity – Better capacity and throughput – Better spectrum efficiency – Finer resource granularity • Coverage – Better coverage for higher data rate.
Release 99 Down link Limitations • Limited Peak Data Rate • Capacity and Throughput • Minimum TTI of 10 ms
Features of HSDPA • Extension of DSCH • Adaptive modulation and coding – QPSK and 16-QAM – Multi coding transmission – Fast feedback of channel condition • Improve transmission efficiency – Fast retransmission and Physical Layer HARQ • Fast resource management – Node B scheduling • Reduce transmission latency – 2 ms TTI
New HSDPA Channels Transport Channel • High Speed Downlink Shared Channel (HS-DSCH) Physical Channels • High Speed Shared Control Channel (HS-SCCH) • High Speed Physical Downlink Shared Channel (HS-PDSCH) • High Speed Dedicated Physical Control Channel (HS-DPCCH)
HS – SCCH Sub frame information - Channelization-code-set information (7 bits) – Modulation scheme information (1 bit) – Transport-block size information (6 bits) – Hybrid-ARQ process information (3 bits) – Redundancy and constellation version (3 bits) – New data indicator (1 bit) – UE identity (16 bits) One UE can receive up to 4 HS-SCCH channels.
Release 99 Uplink Limitations • Large Scheduling Delays – Slow scheduling from RNC • Large Latency – Transmission Time Interval (TTI) durations of 10/20/40/80 ms – RNC based retransmissions in case of errors • Limited Uplink Data Rate – Deployed peak data rate is 384 kbps
Features of HSUPA <ul><li>Maximum transmission rate of 5.76Mbps
CPC Enhancements In Uplink: · A new UL DPCCH slot format · UL DPCCH gating/discontinuous transmission · Implicit CQI reporting reduction In the Downlink: · F-DPCH gating in DL · Discontinuous reception (DRX) at the UE