Primary RLC Entity for 5G Dual Connectivity
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Solution Overview
Problem
The existing dual-connectivity solution in 5G wireless communication systems imposes a heavy burden on the PDCP layer and F1 interface due to additional functionalities such as data buffering, packet reordering, traffic splitting, and channel quality reporting, leading to increased complexity and resource inefficiency, and requires duplicate PDCP and RLC deployments, which complicates network implementation and increases radio link failure probabilities.
Innovation Solution
The solution introduces a primary RLC entity that separates and manages packets across multiple RLC entities, offloading transport layer functionalities from the PDCP layer to the RLC layer, allowing for single PDCP deployment, decoupling RLC entities from radio links, and presenting a unified RLC view to the UE, thereby simplifying the network architecture and improving resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PDCP layer maintains local data buffers for both DL and UL packets to support dual-connectivity, then the reliability of data transmission is improved, but the device complexity and memory burden of the PDCP layer increase significantly
Solution Approach 1:
The patent extracts the data buffering functionality from the PDCP layer and relocates it to the RLC layer. The RLC layer now maintains the data buffers for both downlink and uplink packets, while the PDCP layer focuses on its core functions of packet assembly and sequence management. This separation reduces the memory burden and complexity of the PDCP layer while maintaining transmission reliability through the RLC layer's buffer management capabilities.
2Stability of the object's composition
If the PDCP layer reorders out-of-order packets received from gNB and eNB in dual-connectivity, then the in-sequence data delivery is improved, but the processing burden and complexity of the PDCP layer increase
Solution Approach 1:
The patent extracts the packet reordering functionality from the PDCP layer and implements it in the RLC layer. The RLC layer now handles the reordering of out-of-order packets received from multiple radio links (gNB and eNB), using its buffer to store packets temporarily until they can be delivered in sequence. This reduces the processing burden on the PDCP layer while maintaining stable in-sequence data delivery to the upper layers.
3Productivity
If the PDCP layer splits traffic according to air channel quality in dual-connectivity, then the throughput optimization is improved, but the measurement precision and processing burden increase
Solution Approach 1:
The patent introduces the RLC layer as an intermediary between the PDCP layer and the radio interface. The RLC layer now performs the traffic splitting function based on air channel quality measurements, acting as a mediator that receives data from the PDCP layer and distributes it to appropriate radio links (gNB or eNB). This separates the throughput optimization function from the PDCP layer, reducing its complexity while maintaining productivity through intelligent traffic routing based on channel conditions.
4Reliability
If duplicate PDCP and RLC entities are deployed for each radio link in dual-connectivity, then the radio link failure probability is reduced, but the network implementation complexity increases
Solution Approach 1:
The patent merges the RLC layer functionalities across multiple radio links into a single unified RLC layer instance at the gNB. Instead of deploying separate RLC entities for each radio link (gNB and eNB), the unified RLC layer manages packets for both links, maintaining redundancy and failover capabilities while reducing implementation complexity. The PDCP layer continues to operate with its dual-connectivity architecture, but the RLC layer consolidation simplifies the overall network implementation while maintaining reliability.
Data Source
AI summary
A method in a first network node, which comprises a primary Radio Link Control (RLC) entity is provided. The method comprises: receiving packets from a PDCP entity and sending packets to a PDCP entity; separating the received packets into at least a first group and a second group; assigning sequence numbers to the packets of the first group from a sequence number range allocated to at least one the secondary RLC entity in a second network node, the at least one secondary RLC connected to the primary RLC entity through a RLC channel; sending the packets of the first group with the assigned sequence numbers to the at least one secondary RLC entity.