Cell Selection Using Uplink Path-Loss Evaluation
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Solution Overview
Problem
Conventional cell selection methods in cellular communications, such as those used in LTE and 5G networks, do not consider uplink channel conditions, leading to inefficient cell selection and performance degradation due to higher uplink path-loss, as they primarily focus on downlink channel conditions.
Innovation Solution
User Equipment (UE) is configured to evaluate both downlink and uplink channel conditions, including path-loss and key performance indicators, to select the optimal cell for synchronization, using synchronization signal-reference signal received power (SS-RSRP) in 5G networks and primary and secondary synchronization signals (PSS/SSS) in LTE networks, within specific threshold decibel ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional cell selection methods focus only on downlink channel conditions, then the cell selection process is simple, but uplink performance degrades due to higher path-loss
Solution Approach 1:
The patent changes the selection criterion from only downlink channel conditions to a composite parameter that includes both downlink and uplink channel conditions. Specifically, it introduces uplink path-loss as an additional parameter to be evaluated, transforming the cell selection process from considering single-parameter (downlink RSRP) to multi-parameter evaluation (downlink RSRP + uplink path-loss), thereby resolving the contradiction between simplicity and uplink performance.
2Ease of operation
If UE selects cell based only on downlink conditions, then selection criteria is easy to implement, but UE performance degrades due to not considering uplink path-loss
Solution Approach 1:
The patent modifies the cell selection criteria by adding uplink path-loss as a second evaluation parameter alongside downlink RSRP. This parameter change transforms the selection process from a single-metric comparison to a two-metric comparison, making implementation slightly more complex but significantly improving UE communication performance by selecting cells with better overall channel conditions.
Solution Approach 2:
The patent creates a composite evaluation metric that combines downlink channel conditions and uplink path-loss characteristics. Instead of relying on a single parameter, it synthesizes multiple parameters into a comprehensive cell evaluation criterion, analogous to composite materials that combine multiple properties to achieve superior overall performance.
3Measurement precision
If UE evaluates both downlink and uplink channel conditions, then cell selection accuracy improves, but evaluation complexity increases
Solution Approach 1:
The patent introduces additional measurement parameters (uplink path-loss) to complement the existing downlink RSRP measurements. This parameter expansion enables more accurate cell selection by capturing both directions of communication quality, accepting the trade-off of increased evaluation complexity in exchange for significantly improved selection accuracy.
Data Source
AI summary
The present application relates to improving a roaming service. In an example, user equipment (UE) initiates a cell selection process to choose between a first cell and a second cell. The UE evaluates a first uplink (UL) channel condition of the first cell and a second UL channel condition of the second cell based on the initiation. The UE selects the first cell or the second cell based on the evaluated first UL channel condition and second UL channel condition. The UE initiates a random access channel (RACH) procedure based on the selected first cell or second cell.