UL-SCH Msg3 Transmission Prioritization in LTE Random Access
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Solution Overview
Problem
In LTE wireless communication systems, uplink shared channel (UL-SCH) transmissions during random access procedures can collide with retransmissions of transport blocks stored in the UL HARQ buffer due to TTI bundling, leading to inefficiencies and potential data loss, as the network cannot differentiate between normal and TTI bundling HARQ RTTs.
Innovation Solution
A method and apparatus that prioritize Msg3 transmissions during random access procedures, ensuring they do not collide with retransmissions of transport blocks stored in different HARQ processes by scheduling Msg3 transmissions over existing retransmissions and potentially replacing or skipping these retransmissions when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TTI bundling is used to improve uplink coverage, then uplink coverage and reliability are improved, but Msg3 transmission during random access may collide with retransmissions of transport blocks stored in UL HARQ buffer
Solution Approach 1:
The patent applies preliminary action by flushing the UL HARQ buffer before Msg3 transmission when TTI bundling is detected. This proactive clearing of the buffer prevents potential collisions between Msg3 and stored transport blocks, ensuring reliable random access procedure while maintaining the benefits of TTI bundling for uplink coverage enhancement.
Solution Approach 2:
The patent implements dynamic handling of HARQ processes by detecting whether TTI bundling is active and adaptively adjusting the Msg3 transmission strategy accordingly. When TTI bundling is detected, the system dynamically flushes the UL HARQ buffer; when not detected, it allows normal HARQ operations to proceed, optimizing both coverage and reliability under different operating conditions.
2Productivity
If Msg3 transmission is prioritized over existing retransmissions, then random access procedure efficiency is improved, but retransmission of stored transport blocks may be delayed or skipped
Solution Approach 1:
The patent applies preliminary action by flushing the UL HARQ buffer before Msg3 transmission when TTI bundling is detected. This proactive clearing of the buffer prevents potential collisions between Msg3 and stored transport blocks, ensuring reliable random access procedure while maintaining the benefits of TTI bundling for uplink coverage enhancement.
Solution Approach 2:
The patent applies local quality by differentiating the handling of different HARQ processes and transport blocks. Msg3 transmission is prioritized in the random access context, while other transport blocks are handled according to their specific requirements. The buffer flushing operation selectively affects only the UL HARQ buffer contents, preserving other system operations.
3Device complexity
If the network cannot differentiate between normal and TTI bundling HARQ RTTs, then system complexity is reduced, but transmission timing and resource allocation become inefficient
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously detect whether TTI bundling is active through analysis of received transmissions. The UE independently determines the TTI bundling status and adjusts its Msg3 transmission strategy accordingly, without requiring additional network signaling or complex network-side differentiation mechanisms. This self-service approach maintains simple network operations while achieving efficient transmission timing.
Solution Approach 2:
The patent applies parameter changes by modifying the UE's transmission behavior based on detected TTI bundling parameters. When TTI bundling is detected, the UE changes its HARQ RTT handling and buffer management parameters; when not detected, it uses standard parameters. This dynamic parameter adjustment optimizes transmission efficiency without increasing system complexity.
Data Source
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AI summary
A method for handling Uplink Shared Channel (UL-SCH) transmission in a User Equipment (UE) of a wireless communication system is disclosed. The method includes steps of performing an UL-SCH transmission, and prioritizing a Message 3 (Msg3) transmission when the Msg3 transmission and a retransmission of a transport block (TB) already stored in an UL HARQ buffer of the UE are scheduled at the same time.