Inter-eNB Carrier Aggregation Bearer Configuration for 2DL 1UL
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Solution Overview
Problem
The existing LTE system cannot realize 2DL, 1UL Inter-eNB CA due to the inability to configure the information element DRB-ToAddMod to distinguish between downlink and uplink bearers, leading to significant impact on mobile stations.
Innovation Solution
A mobile communication method that sets bearers #1 and #2 between radio base stations MeNB and SeNB, using the Option 2 architecture for downlink and Option 1 for uplink, with RRC Connection Reconfiguration to dynamically select the bearer for uplink transmission, and modifying the DRB-ToAddMod information element to enable 2DL, 1UL Inter-eNB CA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 2UL Inter-eNB CA is realized to enhance throughput in both uplinks and downlinks, then throughput enhancement is improved, but processing complexity in mobile station UE increases significantly
Solution Approach 1:
The invention segments the carrier aggregation configuration into separate downlink and uplink components. The downlink uses 2DL CA with bearers #1 and #2 through MeNB and SeNB, while the uplink uses 1UL CA through a single selected bearer. This segmentation allows the mobile station to process only one uplink bearer at a time, reducing processing complexity while maintaining downlink throughput enhancement.
Solution Approach 2:
The invention applies different carrier aggregation configurations to different directions (downlink vs uplink). The downlink employs full CA with multiple bearers for maximum throughput, while the uplink uses a simplified single-bearer configuration for reduced complexity. This local differentiation optimizes each direction according to its specific requirements.
2Ease of operation
If the existing DRB-ToAddMod information element is used for bearer configuration, then ease of operation is maintained, but the ability to realize 2DL, 1UL Inter-eNB CA is lost
Solution Approach 1:
The invention segments the bearer configuration capability into separate downlink and uplink configuration mechanisms. The DRB-ToAddMod IE is enhanced to include direction-specific indicators that allow separate configuration of downlink bearers (#1, #2) and uplink bearers. This segmentation enables the existing IE structure to support the new 2DL, 1UL CA mode while maintaining backward compatibility.
Solution Approach 2:
The invention introduces dynamic configuration capability to the DRB-ToAddMod IE through direction indicators and bearer selection mechanisms. The system can dynamically switch between different CA modes (2DL, 1UL) based on current network conditions and mobile station capabilities, providing adaptability while maintaining ease of operation through standardized IE modifications.
Data Source
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AI summary
An object is to realize "2DL, 1UL" "Inter-eNB CA". A mobile communication method according to the present invention includes, a radio base station (MeNB) transmitting, when a bearer #1 has been set between a mobile station (UE) and the radio base station (MeNB), to the mobile station (UE) an information element "DRB-ToAddMod_SeNB" or "DRB-ToAddMod" that instructs to add a bearer #2 between a radio base station (SeNB) and to modify the settings of the bearer #1; and the mobile station (UE) modifying, according to the information element "DRB-ToAddMod_SeNB" or "DRB-ToAddMod", the settings of the bearer #1, and adding the bearer #2 to receive a downlink signal via the bearer #1 and the bearer #2 and transmit an uplink signal via either the bearer #1 or the bearer #2.