Dual Connectivity via X2 Backhaul Link for Small Cell Coverage
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Solution Overview
Problem
Existing wireless communication systems face challenges in providing efficient dual connectivity between macro cells and small cells, particularly in areas with poor macro cell coverage, where split protocol stack processing for radio bearers is needed but lacks effective control information communication mechanisms.
Innovation Solution
Establishing a backhaul link between small cell eNBs and macro cell eNBs via an X2 interface to facilitate dual connectivity, with the small cell eNB performing protocol stack processing on select layers excluding the PDCP layer, and receiving control information from the macro cell eNB to support efficient protocol stack processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If small cells are deployed to serve UEs in areas with poor macro cell coverage, then coverage and data throughput are improved, but device complexity and control information management become more complex
Solution Approach 1:
The protocol stack processing is segmented between macro cell eNB and small cell eNB. The macro cell eNB handles PDCP layer and above, while the small cell eNB handles RLC, MAC, and PHY layers. This segmentation allows the small cell to provide enhanced coverage and throughput without requiring the small cell to process all protocol layers, thus managing complexity.
Solution Approach 2:
The X2 interface acts as an intermediary between the macro cell eNB and small cell eNB, enabling controlled information exchange. This intermediary mechanism facilitates dual connectivity by allowing the small cell to receive necessary control information from the macro cell without direct complex interactions, simplifying the control information management architecture.
2Productivity
If split protocol stack processing is implemented for radio bearers, then dual connectivity performance is improved, but information communication between cells becomes more challenging
Solution Approach 1:
The X2 interface establishes a feedback mechanism where the macro cell eNB receives information from the small cell eNB about radio bearer status and provides corresponding control information in response. This feedback loop ensures that control information is accurately communicated and acted upon, preventing information loss while enabling split protocol stack processing for improved dual connectivity performance.
3Productivity
If small cell eNB performs protocol stack processing on lower layers, then data throughput is enhanced, but control information reception and processing becomes more complex
Solution Approach 1:
The protocol stack is segmented such that the small cell eNB processes only the lower layers (RLC, MAC, PHY) which are computationally intensive for data throughput, while the macro cell eNB handles the higher layers (PDCP and above). This segmentation enables the small cell to enhance data throughput without bearing the full burden of complete protocol stack processing complexity.
Solution Approach 2:
The X2 interface serves as an intermediary that delivers necessary control information from the macro cell eNB to the small cell eNB. This intermediary mechanism simplifies the small cell's processing complexity by providing pre-prepared control information that the small cell can directly use for its lower layer processing, rather than needing to generate or process all control information itself.
Data Source
AI summary
Examples are disclosed for facilitating dual connectivity for user equipment (UE) in a wireless network. The examples include establishing a backhaul link between base stations serving as primary and secondary cells for separate UE connections to management or gateway entities for the wireless network. The primary base station may provide macro cell coverage for the one or more UEs while the secondary base station may provide small cell coverage. The two base stations may split at least some protocol stack processing for radio bearers associated with the separate UE connections. Control information may be exchanged through the backhaul link to facilitate the split protocol stack processing. Other examples are described and claimed.