LTE Physical Cell Identity Allocation Using Radio Map Interference Minimization
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Solution Overview
Problem
In LTE mobile communication networks, the allocation of physical cell identities (PCI) leads to collisions and poor key performance indicators, especially in scenarios with overlapping cells, due to conventional methods failing to optimally avoid collisions based on radio frequency signal levels.
Innovation Solution
A method involving the generation of a radio map to optimize PCI allocation by considering interference, noise, and signal levels, using a network element to select optimal PCI modulo 3 and 30 values based on cumulative interference minimization or signal-to-interference ratio maximization, thereby reducing collisions and improving network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PCI allocation methods are used, then the allocation process is simple, but collisions occur and key performance indicators deteriorate in overlapping cell scenarios
Solution Approach 1:
The patent performs preliminary actions by generating a radio map before PCI allocation to capture the actual radio frequency signal levels and interference patterns in the network. This pre-analysis enables informed PCI assignment decisions that avoid collisions in overlapping cell scenarios, improving reliability without requiring complex real-time adjustments during operation
Solution Approach 2:
The patent implements feedback mechanisms by using measured or simulated radio signal levels and interference patterns to guide PCI allocation decisions. The system continuously monitors network performance and adjusts PCI assignments based on feedback from radio map analysis, enabling adaptive optimization that resolves collisions while maintaining manageable complexity through automated control loops
2Reliability
If PCI allocation does not consider radio frequency signal levels, then the allocation process is straightforward, but collisions occur between overlapping cells
Solution Approach 1:
The patent performs preliminary radio map generation and signal level analysis before PCI allocation to identify potential collision zones. By pre-characterizing the radio frequency environment, the system can make informed PCI assignments that avoid overlaps, achieving reliable collision avoidance through upfront planning rather than complex real-time coordination
Solution Approach 2:
The patent changes the allocation approach by incorporating radio frequency signal level parameters and interference patterns into the PCI assignment process. Instead of using fixed or random allocation, the system dynamically adjusts PCI assignments based on measured or simulated radio conditions, transforming the allocation from a static procedure to an adaptive process that resolves collisions while maintaining manageable complexity through parameter-driven decision-making
3Productivity
If optimal PCI allocation is implemented considering radio map data, then key performance indicators improve, but the complexity of the allocation system increases
Solution Approach 1:
The patent performs preliminary radio map generation and network characterization before PCI allocation to establish a foundation for optimized assignments. This upfront analysis captures signal levels, interference patterns, and cell geometry, enabling high-performance allocation decisions without requiring complex real-time computation during network operation, thus improving productivity while controlling system complexity
Solution Approach 2:
The patent implements feedback loops that monitor network performance and adjust PCI allocations based on radio map data and measured signal conditions. This automated control mechanism enables continuous optimization of key performance indicators through adaptive reconfiguration, achieving high productivity while managing complexity through systematic feedback-driven adjustment rather than manual intervention
Data Source
AI summary
A method includes generating, by a network element, a radio map of a single-frequency network having multiple cells. The radio map represents power levels of radio signals at several locations in the network. A first function is selected to be applied, wherein the first function is based on the radio map and includes physical cell identity, PCI, modulo 3 values for the multiple cells as input. Different combinations of the PCI modulo 3 values are applied in the first function. Each candidate PCI modulo 3 value is selected from a group of three available options. An output of the first function is determined with respect to each combination. It is determined which combination provides the output fulfilling a predefined criterion. Those PCI modulo 3 values, which correspond to the output fulfilling the predefined criterion, are allocated to the multiple cells in order to reduce interference between primary synchronization sequences.