PDCP PDU Identity Routing in LTE-WLAN Dual Connectivity
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Solution Overview
Problem
In LTE-WLAN aggregation, there is no existing radio resource integration mechanism, leading to confusion for the UE when receiving split radio bearers from both LTE and WLAN, as the WiFi AP lacks awareness of the split radio bearer protocol and cannot route data correctly to the appropriate PDCP entity.
Innovation Solution
Assigning an identity to each PDCP PDU by the eNB indicates which PDCP entity it belongs to, allowing the UE to correctly route data upon receiving it from the WiFi AP, and introducing new adaptor layers on both the eNB and UE sides to manage these identities and ensure proper delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If split radio bearer technique is used to transmit data via both MeNB and SeNB, then throughput is improved, but routing confusion occurs at the UE side because the WiFi AP cannot identify which PDCP entity the data belongs to
Solution Approach 1:
The patent introduces an identity field as an intermediary element that mediates between the WiFi AP and the UE's PDCP entities. This identity field carries routing information through the WiFi interface, enabling the UE to correctly identify which PDCP entity should handle the received data without requiring the WiFi AP to understand PDCP protocols.
Solution Approach 2:
The patent segments the routing information into a separate identity field that can be independently transmitted through the WiFi interface. This segmentation allows the routing information to be carried separately from the data payload, enabling the WiFi AP to forward data with embedded routing identifiers without needing to interpret the actual data content or PDCP structure.
2Device complexity
If WiFi AP transmits split RB as normal data without protocol awareness, then device complexity is reduced, but the UE cannot correctly route received data to the appropriate PDCP entity
Solution Approach 1:
The identity field serves as an intermediary that bridges the simplicity of WiFi AP data forwarding with the complexity requirements of PDCP entity routing. The WiFi AP only needs to forward data with this identity tag attached, while the UE uses the identity to route to the correct PDCP entity, thus maintaining WiFi AP simplicity while enabling correct routing.
Solution Approach 2:
The patent changes the parameter space by introducing an identity parameter that transforms the routing problem from a protocol-interpreation task (requiring high complexity) to a parameter-matching task (requiring low complexity). The WiFi AP operates with simple parameter forwarding, while the UE performs parameter-based routing decisions.
Data Source
AI summary
A method of radio bearer transmission in dual connectivity for a network in a long term evolution (LTE) system comprises generating at least a packet data convergence protocol protocol data unit (PDCP PDU) by a PDCP entity of the network corresponding to a radio bearer (RB), and assigning each PDCP PDU with an identity, wherein the identity indicates which PDCP entity the PDCP PDU belongs to.