Master RLC Pre-Assignment for Carrier Aggregation Backhaul Latency
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Solution Overview
Problem
In wireless communication systems supporting carrier aggregation, data transmission efficiency is hindered by latency between base stations, leading to wasted frequency resources and increased latency in retransmissions, particularly in non-ideal backhaul conditions.
Innovation Solution
The RLC function is hierarchized and distributed across base stations, with pre-assignment of RLC sequence numbers to PDCP packets, enabling stable operation and reducing retransmission time by eliminating status PDU loss and minimizing memory requirements for ARQ retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data transmission is performed through carrier aggregation between base stations connected via non-ideal backhaul, then transmission capacity is increased, but latency between base stations causes frequency resource waste and retransmission delays
Solution Approach 1:
The patent segments the RLC function into master RLC and slave RLC components distributed across different base stations. The master RLC (in first base station) handles PDCP packet reception, RLC sequence number assignment, and status PDU generation, while the slave RLC (in second base station) handles RLC PDU transmission and acknowledgment. This functional segmentation allows each base station to operate more independently, reducing the impact of backhaul latency on overall transmission efficiency.
2Reliability
If RLC status PDU is transmitted over non-ideal backhaul, then retransmission control is maintained, but status PDU loss occurs and retransmission time increases
Solution Approach 1:
The patent extracts the status PDU generation and management functions from the distributed slave RLC and concentrates them in the master RLC at the first base station. The slave RLC only transmits RLC PDUs and receives acknowledgments, while the master RLC generates status PDUs based on received acknowledgments and manages retransmissions. This extraction eliminates the need for status PDU transmission over the non-ideal backhaul, preventing status PDU loss and reducing retransmission delays.
3Device complexity
If RLC function is centralized in one base station, then protocol operation is simplified, but data transmission efficiency decreases due to backhaul latency
Solution Approach 1:
The patent introduces a hierarchical dimension to the RLC protocol operation, with master RLC and slave RLC operating at different functional levels. The master RLC handles high-level control functions (PDCP packet management, RLC SN assignment, status PDU generation), while the slave RLC handles low-level transmission functions (RLC PDU formation, acknowledgment reception). This dimensional differentiation allows distributed operation that improves transmission efficiency while maintaining protocol simplicity through clear functional separation.
Data Source
AI summary
The disclosure relates to a method and a device therefor, wherein the method is applied to CA between base stations including multiple base stations connected through non-ideal backhaul, has a master RLC pre-assign an RLC SN to a PDCP PDU and transmit the PDCP PDU to a slave RLC of each base station, and has the master RLC take full responsibility for ARQ retransmission management, thereby enabling more efficient use of a network resource and a reduction in the time spent for a retransmission.