Dual Connectivity PDCP Entity Segmentation for Radio Link Failure
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Solution Overview
Problem
In dual connectivity wireless communication systems, when a radio link failure occurs on a connection to a small eNB, the UE initiates a RRC connection re-establishment procedure, which can lead to unnecessary suspension of data transmission and reception over the macro eNB, even if the connection to the macro eNB is still stable.
Innovation Solution
The method involves configuring a communication device to connect to both a macro eNB and a small eNB with separate PDCP and RLC entities, and when a radio link failure is detected on one connection, the device continues data transmission and reception through the other connection without initiating a RRC connection re-establishment procedure, allowing uninterrupted data flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE initiates a RRC connection re-establishment procedure when a radio link failure is detected on one connection, then the connection reliability is improved, but the data transmission and reception over the other stable connection is unnecessarily suspended
Solution Approach 1:
The patent segments the data transmission paths by maintaining separate PDCP entities for each eNB connection. When a radio link failure occurs on one connection, only that specific PDCP entity is re-established, while the other PDCP entity continues to handle data transmission normally. This segmentation allows independent recovery of each connection without affecting the other stable connection.
Solution Approach 2:
The patent applies local quality by making the recovery behavior connection-specific. Each PDCP entity has its own recovery mechanism, so the re-establishment procedure is applied locally to only the affected connection rather than globally to all connections. This ensures that the stable connection maintains its quality while the failed connection undergoes re-establishment.
2Device complexity
If the UE suspends all radio bearers except SRB0 during RRC connection re-establishment, then the re-establishment process is simplified, but the data transmission over the stable connection is interrupted
Solution Approach 1:
The patent segments the radio bearers by maintaining separate PDCP entities for each eNB connection. During re-establishment, only the bearers associated with the failed connection are suspended, while bearers on the stable connection continue to operate. This segmentation allows the re-establishment procedure to be applied locally without globally suspending all data transmissions.
Solution Approach 2:
The patent applies partial action by selectively suspending only the necessary bearers for re-establishment rather than suspending all bearers. This partial approach minimizes the impact on ongoing data transmissions while still providing the necessary re-establishment functionality for the failed connection.
3Device complexity
If a centralized PDCP entity is used at the macro eNB for both macro and small eNB, then the security and header compression are centralized, but the data transmission flexibility and QoS balancing are reduced
Solution Approach 1:
The patent segments the PDCP functionality by maintaining separate PDCP entities at each eNB (macro and small cell). This segmentation allows each eNB to independently manage its own data transmission, providing flexibility in QoS balancing and adaptability in handling different traffic conditions, while still maintaining centralized security and header compression through the RRC entity.
Solution Approach 2:
The patent resolves the contradiction by adding a dimensional separation between PDCP entities at different locations (macro eNB and small eNB), while maintaining logical connectivity through the RRC entity. This spatial distribution of PDCP entities enables independent data transmission management while preserving centralized security control through the RRC layer.
Data Source
AI summary
A method of handling data transmission and reception in dual connectivity, for a communication device in a wireless communication system is disclosed. The method comprises connecting to at least two evolved base station (eNBs) including a first eNB and a second eNB in the wireless communication system, being configured a packet data convergence protocol (PDCP) entity corresponding to at least two radio link control (RLC) entities including a first RLC entity for receiving/transmitting data from/to the first eNB and a second RLC entity for receiving/transmitting data from/to the second eNB, and when detecting a radio link failure a connection to the second eNB, not initiating a radio resource control (RRC) connection re-establishment procedure for connection recovery.