Uplink Cell Selection via Relative Path Loss
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Solution Overview
Problem
In cellular networks with overlapping frequency bands, the selection of cells based on minimum absolute path loss does not account for inter-cell interference, leading to increased interference for nearby user equipment (UEs) and reduced signal-to-noise ratio (SNR), which adversely affects data throughput.
Innovation Solution
The solution involves determining the path loss between a UE and its considered cell and neighboring cells to select the uplink frequency band with the minimum relative path loss, thereby maximizing the relative uplink channel gain and reducing interference, while also considering a path loss threshold to ensure sufficient channel gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cell selection is based on minimum absolute path loss, then uplink signal strength at the base station is maximized, but inter-cell interference increases for nearby UEs
Solution Approach 1:
The patent changes the cell selection parameter from absolute path loss to relative path loss. Instead of selecting the cell with minimum absolute PL, the system calculates relative PL as the difference between the considered cell's PL and the best neighbor cell's PL, then selects the cell with minimum relative PL. This parameter transformation resolves the contradiction by optimizing for both signal strength and interference reduction simultaneously.
2Reliability
If UEs are assigned to cells with minimum absolute path loss, then channel gain is maximized, but signal-to-noise ratio decreases due to increased interference
Solution Approach 1:
The system transforms the channel selection criterion from absolute path loss to relative path loss calculation. By computing relative PL (difference between considered cell PL and best neighbor cell PL) and selecting based on minimum relative PL, the system simultaneously optimizes channel gain while reducing interference-induced noise, thereby improving SNR without sacrificing reliability.
3Ease of operation
If cell selection ignores inter-cell interference, then uplink assignment is simplified, but data throughput decreases due to reduced SNR
Solution Approach 1:
The patent modifies the cell selection parameter from simple absolute path loss to relative path loss, which incorporates interference information from neighbor cells. This parameter change maintains computational efficiency while significantly improving data throughput by selecting cells that provide better SNR through reduced inter-cell interference.
4Ease of operation
If minimum absolute path loss is used for cell selection, then uplink channel assignment is straightforward, but load balancing deteriorates
Solution Approach 1:
By changing the selection parameter to relative path loss (difference between considered cell PL and best neighbor cell PL), the system achieves better load balancing across the network. The relative PL metric naturally distributes UEs more evenly by considering neighbor cell conditions, improving network adaptability while maintaining assignment simplicity.
Data Source
AI summary
Solutions for interference aware uplink cell selection for a user equipment (UE) include: determining a path loss (PL) between the UE and a considered cell; determining a PL between the UE and a neighbor cell; based on at least the PL between the UE and the considered cell and the PL between the UE and the neighbor cell, determining a cell with an uplink frequency band having a minimum relative PL for the UE; and assigning, to the UE, the cell with the uplink frequency band having the minimum relative PL. In some examples, the network includes both 5G and 4G cells. Some examples include determining whether the PL for the cell having the minimum relative PL for the UE meets a PL threshold and if so, assigning, to the UE, the cell with the uplink frequency band having the minimum absolute PL for the UE.