NR Capability Handling in Inter-RAT Handover Signaling
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Solution Overview
Problem
The challenge in 5G wireless communication systems is handling network capabilities during inter-RAT handovers between different radio access technologies, particularly for new radio (NR) capabilities, where existing methods are unclear on how to manage transitions effectively.
Innovation Solution
A communication device and method that involve a network with a first base station of a new radio (NR) Radio Access Network (NR-RAN) and a second base station of an Evolved Universal Terrestrial Radio Access (E-UTRA) Network (E-UTRAN), where the first base station transmits E-UTRA and NR capabilities to the second base station, generating a Radio Resource Control (RRC) Connection Reconfiguration message, which is then transmitted back to the first base station, enabling a seamless handover by processing NR-access RRC messages and confirming the handover with a RRC Connection Reconfiguration Complete message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing handover methods are used for inter-RAT transitions, then the handover process can be completed, but the NR capabilities cannot be properly managed or transferred between different radio access technologies
Solution Approach 1:
The patent introduces an intermediary mechanism where the source base station (NR-RAN) and target base station (E-UTRAN) exchange capability information through defined signaling procedures. The RRC Connection Reconfiguration message acts as a mediator to carry capability information between different RATs, enabling proper capability management during handover without requiring direct compatibility between NR and E-UTRA protocols
Solution Approach 2:
The patent implements preliminary action by having the source base station determine and prepare capability information (E-UTRA capability and NR capability) before the handover execution. The capability information is pre-processed and included in the handover command message, so that the target base station receives ready-to-use capability data, avoiding capability management issues during the actual handover transition
2Loss of information
If NR capabilities are transmitted during handover, then capability information is available for the target network, but the complexity of the handover signaling increases
Solution Approach 1:
The patent segments capability information into distinct types: E-UTRA capability and NR capability. Each capability type is handled separately in the signaling flow, with the source base station determining each type and including them in the RRC Connection Reconfiguration message. This segmentation allows the target base station to process each capability type appropriately for its specific RAT requirements, reducing overall signaling complexity
Solution Approach 2:
The RRC Connection Reconfiguration message serves multiple functions: it acts as a handover command, carries E-UTRA capability information, and transports NR capability information. This multi-functionality reduces the need for separate signaling messages for each capability type, thereby reducing overall signaling complexity while ensuring complete capability information transfer
Data Source
AI summary
A method for handling NR capabilities comprises the first BS transmitting at least one E-UTRA capability and at least one first NR capability of a communication device to the second BS; the second BS generating a RRC Connection Reconfiguration message according to the at least one E-UTRA capability and the at least one first NR capability, wherein the RRC Connection Reconfiguration message comprises at least one E-UTRA configuration and a NR configuration; the second BS transmitting the RRC Connection Reconfiguration message to the first BS; the first BS generating a first NR-access RRC message comprising the RRC Connection Reconfiguration message; the first BS transmitting the first NR-access RRC message to the communication device; and the second BS receiving a RRC Connection Reconfiguration Complete message from the communication device.