Physical Layer Sub-Cell Identity Allocation in Wireless Networks
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Solution Overview
Problem
Existing wireless network standards, such as LTE and 5G NR, face challenges in allocating physical layer sub-cell identities, leading to conflicts between adjacent or neighbor cells/sectors, which degrade cell search performance.
Innovation Solution
A method for allocating physical layer sub-cell identities involves selecting a sub-cell identity vector for a network device in a wireless network. This involves removing candidates with duplicate sub-cell identities for adjacent sectors, determining conflict measurements with neighbor cells, and selecting the optimal sub-cell identity vector based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the same sub-cell identity is allocated to multiple sectors of a network device, then the PCI reuse distance is maximized, but sub-cell identity conflicts occur between adjacent sectors and neighbor cells, degrading cell search performance
Solution Approach 1:
The patent segments the PCI into two components: PCI-group and sub-cell identity. By separating these components, the system can maximize PCI reuse distance through PCI-group allocation while preventing sub-cell identity conflicts through careful sub-cell identity assignment. This segmentation allows independent optimization of each component to resolve the contradiction between reuse distance and cell search performance.
Solution Approach 2:
The patent applies different allocation strategies to different components of the PCI based on their specific requirements. The PCI-group is allocated to maximize reuse distance, while the sub-cell identity is allocated to avoid conflicts in adjacent sectors and neighbor cells. This local quality approach allows each component to be optimized for its specific function, resolving the overall contradiction.
2Reliability
If sub-cell identity conflicts are minimized through careful allocation, then cell search performance is improved, but the complexity of PCI planning increases
Solution Approach 1:
By segmenting the PCI into PCI-group and sub-cell identity, the patent simplifies the planning process. The PCI-group can be allocated using standard methods to maximize reuse distance, while the sub-cell identity can be assigned to avoid local conflicts. This segmentation breaks down the complex PCI planning problem into simpler, more manageable sub-problems.
Solution Approach 2:
The patent performs preliminary identification of adjacent sectors and neighbor cells before finalizing the sub-cell identity allocation. By pre-determining which sectors are adjacent and which cells are neighbors, the system can proactively avoid conflicts rather than reacting to them, simplifying the overall planning process.
3Reliability
If all possible sub-cell identity vector candidates are evaluated to find the optimal allocation, then the optimal PCI planning is achieved, but the computational burden and time required increase significantly
Solution Approach 1:
The patent segments the evaluation process into two stages: first evaluating PCI-group candidates based on reuse distance, then evaluating sub-cell identity assignments based on conflict measurements. This segmentation reduces the search space and computational burden compared to evaluating all possible PCI combinations simultaneously, while still achieving optimal planning.
Solution Approach 2:
The patent uses conflict measurements to evaluate sub-cell identity candidates, which provides a partial assessment rather than requiring complete evaluation of all possibilities. This partial action approach achieves sufficient optimality without the full computational burden of exhaustive search, reducing planning time while maintaining reliability.
Data Source
AI summary
Embodiments of the invention include methods, system, and software for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network. In one embodiment, a method includes selecting a plurality of sub-cell identity vector candidates for the network device from a set of possible sub-cell identity vector candidates, where the selecting removes one or more possible sub-cell identity vector candidates containing a same sub-cell identity for two or more adjacent sectors of the network device. The method further includes determining a plurality of conflict measurements for each of the plurality of sub-cell identity vector candidates. The method continues with deriving a single value from the plurality of conflict measurements for each of the plurality of sub-cell identity vector candidates and selecting the sub-cell identity vector for the network device from the plurality of sub-cell identity vector candidates based on the single value.