Cell Selection in Asymmetric Multi-RAT Coverage
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Solution Overview
Problem
In communication environments with asymmetric uplink and downlink coverage, existing technologies face challenges in selecting the optimal wireless network for user equipment (UE) to ensure reliable data transmission.
Innovation Solution
The method involves a user equipment processor that receives system information on pilot transmission power and permissible uplink reception power from the base station, estimates path loss, and determines access based on these parameters, allowing the UE to switch between different wireless networks for optimal coverage, including cellular and Wi-Fi access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing cell selection technologies are used in multi-RAT environments, then the UE can connect to wireless networks, but the reliability of data transmission deteriorates due to asymmetric uplink and downlink coverage
Solution Approach 1:
The patent changes the parameters used for cell selection from traditional downlink-only metrics to a combination of downlink path loss and uplink coverage parameters. The UE estimates downlink path loss based on reference signal reception and compares it with uplink coverage information received from the base station, thereby adapting the cell selection criteria to asymmetric coverage conditions and improving transmission reliability.
Solution Approach 2:
The base station performs preliminary actions by transmitting uplink coverage information and permissible uplink reception power parameters to the UE before the UE makes cell selection decisions. This allows the UE to proactively evaluate whether the estimated path loss falls within the permissible uplink reception range, preventing connection attempts that would fail due to asymmetric coverage limitations.
2Measurement precision
If the UE selects cells based on traditional methods, then the selection process is simple, but the precision of cell selection deteriorates in asymmetric coverage environments
Solution Approach 1:
The UE performs self-service by autonomously estimating downlink path loss based on received reference signals and comparing it with uplink coverage parameters. The UE independently determines whether to select a cell without requiring complex network-side coordination, thereby improving selection precision while maintaining relatively simple device operation.
Solution Approach 2:
The patent creates a universal cell selection method that works across different RATs (LTE, Wi-Fi, etc.) by using fundamental parameters like path loss estimation and permissible reception power that are applicable to multiple wireless technologies. This multi-functional approach improves precision without significantly increasing complexity, as the same basic principles apply across different network types.
Data Source
AI summary
The present invention provides a method for selecting a cell by a terminal which is capable of establishing a radio connection through a plurality of radio interfaces. The terminal comprises a signal transmitting/receiving unit and a processor connected to the signal transmitting/receiving unit. The processor may receive, from a base station, system information about pilot transmission power and an uplink reception power limit, estimate the amount of path loss on the basis of the pilot transmission power and measured pilot reception power, and determine whether to connect to the base station on the basis of the uplink reception power limit and the amount of path loss.