PCI Allocation for Active Antenna Split Cells
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Solution Overview
Problem
In wireless communication systems, particularly in LTE networks, active antenna systems (AAS) complicate the allocation of physical cell identities (PCIs) due to dynamic cell splitting and merging, making it difficult for user equipment (UEs) to distinguish between split cells and normal cells, which affects handover processes and traffic management.
Innovation Solution
The method involves allocating unique PCIs for split cells of an AAS and broadcasting or transmitting information on the range of these allocated PCIs to UEs and neighboring eNodeBs, ensuring that the ranges of PCIs for split cells do not overlap with those of normal cells, allowing for clear differentiation and efficient traffic management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PCIs are allocated for split cells of AAS without distinguishing them from normal cells, then the PCI allocation process is simple, but UEs cannot distinguish between split cells and normal cells affecting handover processes
Solution Approach 1:
The patent applies local quality by allocating a specific PCI range (e.g., 500-503) exclusively for split cells of AAS, while normal cells use a different PCI range (e.g., 0-500). This localized differentiation enables UEs to distinguish between split cells and normal cells through PCI value comparison, ensuring reliable handover processes while maintaining a systematic and manageable allocation approach.
2Reliability
If unique PCIs are allocated for each split cell of AAS, then split cells can be distinguished from normal cells, but the PCI allocation becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the PCI space into distinct segments: one segment (e.g., 0-500) for normal cells and another segment (e.g., 500-503) for split cells of AAS. This segmented allocation strategy enables clear differentiation between cell types while maintaining systematic management. The eNB can efficiently allocate PCIs by selecting from the appropriate segment based on cell type, reducing allocation complexity despite having unique identifiers for each cell type.
3Reliability
If information on PCI ranges is transmitted to UEs, then UEs can distinguish split cells from normal cells, but signaling overhead increases
Solution Approach 1:
The patent applies partial action by transmitting only the essential PCI range information (e.g., indicating that 500-503 is reserved for split cells) to UEs, rather than providing complete detailed information about all cells. This partial information transmission is sufficient for UEs to distinguish split cells from normal cells through PCI value comparison, while minimizing signaling overhead. The approach balances the need for accurate cell identification with the constraint of limited signaling resources.
Data Source
AI summary
A method and apparatus for allocating physical cell identities (PCIs) in a wireless communication system is provided. An eNodeB (eNB) allocates PCIs for split cells of an active antenna system (AAS), and transmits information on range of the allocated PCIs for split cells of the AAS to user equipments (UEs) or neighbor eNBs.