HSDPA Packet Transmission Timing Indicator
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Solution Overview
Problem
In HSDPA Release 7 operations without HS-SCCH, HARQ retransmissions are restricted to exact timing and predefined redundancy versions, limiting Node B's scheduling flexibility and increasing the UE's processing burden due to blind combining of initial and retransmission packets.
Innovation Solution
The method involves transmitting an initial data packet without a control channel message, followed by a retransmission packet with a control channel message containing a transmission time indicator, which identifies the timing of the previous transmission, allowing the UE to correctly combine and decode the packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HSDPA operation without HS-SCCH is used for small packets, then system capacity is improved and control channel cost is reduced, but HARQ retransmission flexibility is restricted and UE processing burden increases
Solution Approach 1:
The invention pre-allocates specific HS-PDSCH code channels for HARQ retransmissions and defines predetermined redundancy version sequences in advance. This preliminary configuration allows the UE to know exactly where to find retransmissions and what redundancy versions to expect, eliminating the need for blind searching and reducing processing complexity while maintaining high system capacity
2Productivity
If synchronous retransmission with predefined redundancy version sequence is required, then HS-SCCH transmission is eliminated, but Node B scheduling flexibility is reduced
Solution Approach 1:
The invention segments the HARQ process into two distinct parts: initial transmissions use dynamic scheduling with full HS-SCCH control messages allowing flexible Node B decisions, while retransmissions use a separate predetermined pattern with pre-allocated code channels and redundancy version sequences. This segmentation allows both dynamic adaptability for initial transmissions and efficient predictable processing for retransmissions
3Productivity
If blind combining of initial and retransmission packets is required, then HS-SCCH can be eliminated, but UE processing complexity increases
Solution Approach 1:
The invention makes the retransmission process self-service by pre-configuring the UE with specific code channels and redundancy version sequences for retransmissions. The UE can autonomously combine received packets using these predetermined parameters without needing HS-SCCH control messages, thereby reducing control channel overhead while simplifying UE operation through self-service combining
Data Source
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Figure 3
AI summary
A solution for high-speed packet radio communications is provided. According to the provided solution, an initial transmission of a data packet is transmitted on a data channel of a high-speed packet radio service, and the transmission is carried out without a control channel mes- sage. If the data packet is not received, a retransmission data packet is transmitted together with a control channel message comprising a transmission time indicator indicat- ing a transmission time interval of a previous trans-mission of the data packet. A receiver is then able to combine the initial transmission and the retransmission and decode the data packet correctly.