Split Radio Bearer Handover for Interference Reduction
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Solution Overview
Problem
In wireless communications networks, particularly in heterogeneous deployments, there is a challenge in serving User Equipments (UEs) in proximity to two cells with good quality for both downlink (DL) and uplink (UL) transmissions due to differing transmission powers of base stations, leading to lower radio resource utilization and interference issues.
Innovation Solution
The method involves splitting the DL and UL parts of a radio bearer between two cells, allowing the UE to connect to the cell that best serves it for both DL and UL transmissions, using handover requests and acknowledgments to manage the split, and utilizing existing signaling to optimize channel conditions and mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If base stations use different transmission powers in heterogeneous deployments, then coverage and capacity are improved, but interference increases and radio resource utilization decreases
Solution Approach 1:
The patent segments the radio bearer into separate downlink and uplink parts that can be independently assigned to different cells. This allows the UE to connect to a high-power base station for downlink while connecting to a low-power base station for uplink, thereby reducing cross-link interference while maintaining coverage benefits
Solution Approach 2:
The patent enables different quality characteristics for downlink and uplink connections by allowing independent cell selection for each direction. The UE can optimize its downlink connection to one cell and uplink connection to another cell based on local signal conditions, reducing interference in each direction independently
2Area of stationary object
If base stations use different transmission powers in heterogeneous deployments, then coverage and capacity are improved, but radio resource utilization efficiency decreases
Solution Approach 1:
By segmenting the radio bearer into independent downlink and uplink parts, the system enables separate resource allocation and cell selection for each direction. This optimization improves overall resource utilization by allowing UEs to connect to the most suitable cell for each transmission direction based on signal conditions
Solution Approach 2:
The patent introduces dynamic cell selection for downlink and uplink connections, allowing the network to adaptively assign different target cells for each direction based on current signal conditions. This dynamic optimization improves radio resource utilization by preventing UEs from being forced to use suboptimal cells
3Device complexity
If a UE connects to a single cell for both DL and UL, then connection management is simplified, but service quality deteriorates in heterogeneous deployments
Solution Approach 1:
The patent segments the connection management into separate control for downlink and uplink bearers. The network can independently select target cells for DL and UL parts of the same bearer, allowing optimized service quality without requiring complete connection reconfiguration
Solution Approach 2:
The patent applies partial handover where only the uplink or downlink part of a bearer is transferred to a different cell, rather than transferring the entire bearer. This partial action maintains service quality while minimizing connection management complexity
Data Source
AI summary
A method in a first network node for splitting of a DL part and an UL part of a radio bearer between a first cell and a second cell in a wireless communications network. The radio bearer is associated to DL and UL transmissions between the first network node and a user equipment in the first cell. The first network node transmits (1904) a handover request. The handover request indicates splitting of the DL part and the UL part of the radio bearer between the first cell and the second cell. The first network node receives (1905) a handover request acknowledge of the handover request. The handover request acknowledge indicates admission of the splitting.