RLC Entity Sequence Number Length Adjustment for LTE Peak Rate
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Solution Overview
Problem
In LTE systems, the conventional RLC sequence number length is limited to 10 bits, which becomes a bottleneck when carrier aggregation enhances peak rates, leading to throughput reduction during handover operations and SCell activation/deactivation.
Innovation Solution
The RLC sequence number length is dynamically adjusted to 11 bits or more, allowing flexible changes without deactivating SCells during handover, using RRC signaling to re-establish the RLC entity without requiring handover operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the RLC sequence number length is increased to enhance peak rates, then the window control bottleneck is resolved, but the header size of RLC PDU increases
Solution Approach 1:
The patent applies dynamics by making the sequence number length configurable and adaptable. The RLC entity can dynamically adjust the sequence number length based on the number of activated SCells, transitioning between 5-bit, 10-bit, and 11-bit modes as needed, rather than using a fixed sequence number length throughout operation.
Solution Approach 2:
The patent implements parameter changes by modifying the sequence number length parameter according to system conditions. When the number of activated SCells exceeds a threshold, the sequence number length is changed from 10 bits to 11 bits, allowing the system to adapt its parameters to current operational requirements.
2Adaptability or versatility
If handover operations are performed to re-establish RLC entity, then the sequence number length can be changed, but SCell deactivation occurs causing throughput loss
Solution Approach 1:
The patent extracts the sequence number length change operation from the handover procedure. Instead of requiring a full handover to modify the sequence number length, the system separately triggers RLC entity re-establishment only when sequence number length adjustment is needed, removing the unnecessary handover and SCell deactivation steps.
Solution Approach 2:
The patent applies preliminary action by proactively monitoring the number of activated SCells and triggering RLC entity re-establishment before throughput degradation occurs. When the threshold is exceeded, the sequence number length is adjusted in advance, preventing the window control bottleneck before it impacts performance.
3Productivity
If the number of SCells is increased to enhance peak rate, then carrier aggregation capability is improved, but the window control becomes a bottleneck
Solution Approach 1:
The patent applies dynamics by making the sequence number length adaptable to the number of active SCells. As more SCells are activated and the system complexity increases, the sequence number length automatically extends from 10 bits to 11 bits, providing the necessary window size to handle the increased number of simultaneous RLC PDUs.
Data Source
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AI summary
There is provided user equipment for communicating with a base station in a mobile communication system supporting LTE including a reception unit configured to receive an indication from the base station to change a sequence number length of an RLC PDU, a re-establishment unit configured to perform re-establishment of an RLC entity upon receiving the indication, and a communication unit configured to use the RLC PDU with the changed sequence number length to communicate with the base station after completion of the re-establishment.