Supplementary Uplink Carrier Selection for Wireless Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing supplementary uplink (SUL) configurations, particularly in high-frequency bands where regular uplink (RUL) coverage is limited, leading to suboptimal cell selection and handover processes.
Innovation Solution
The implementation of supplementary uplink (SUL) configurations in wireless communication systems, where a WTRU can switch between RUL and SUL based on conditions such as downlink reference signal received power (DL-RSRP thresholds, enabling improved cell suitability criteria and handover management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a WTRU uses regular uplink (RUL) in high-frequency bands, then the system maintains simplicity in uplink configuration, but uplink coverage is limited and cell selection becomes suboptimal
Solution Approach 1:
The uplink is segmented into two separate carriers: RUL (regular uplink) and SUL (supplementary uplink). This segmentation allows the system to use RUL for normal operations and SUL specifically for coverage extension in high-frequency bands, thereby improving uplink coverage without requiring complete reconfiguration of the entire uplink system.
Solution Approach 2:
Different uplink carriers (RUL and SUL) are assigned different qualities and purposes. SUL is specifically configured with better coverage characteristics for high-frequency bands, while RUL maintains standard configuration. This local quality differentiation allows optimal performance in specific scenarios without compromising overall system simplicity.
2Reliability
If the system implements SUL configuration for all cells, then uplink coverage is improved, but cell selection and handover processes become more complex
Solution Approach 1:
The system dynamically selects between RUL and SUL based on real-time conditions such as DL-RSRP thresholds and coverage requirements. This dynamic selection allows the system to adapt to changing channel conditions and traffic patterns, improving ease of operation by automatically choosing the optimal uplink carrier without manual intervention.
Solution Approach 2:
The system uses feedback mechanisms including DL-RSRP measurements and uplink coverage assessments to determine whether to use RUL or SUL. This feedback-driven approach ensures that cell selection and handover decisions are based on actual channel conditions, simplifying the overall process by eliminating the need for complex pre-configured selection criteria.
3Adaptability or versatility
If the system provides both SUL and RUL configurations in handover commands, then uplink flexibility is improved, but handover failure risk increases due to carrier selection complexity
Solution Approach 1:
The system performs preliminary assessments of uplink coverage and channel conditions before executing handover. By evaluating DL-RSRP thresholds and determining the appropriate uplink carrier (SUL or RUL) in advance, the system reduces handover failure risk while maintaining the flexibility to provide both SUL and RUL configurations when needed.
Solution Approach 2:
The system changes key parameters such as DL-RSRP thresholds and uplink carrier selections based on current channel conditions and coverage requirements. These parameter changes enable the system to adaptively choose the optimal handover target and uplink carrier, improving both uplink flexibility and handover success rate.
4Reliability
If the system uses SUL for initial access, then uplink coverage is improved, but the system requires additional cell suitability criteria and configuration management
Solution Approach 1:
Cell suitability criteria are segmented into SUL-specific and RUL-specific evaluations. The system maintains separate configuration sets for SUL and RUL cells, allowing simplified assessment for each type while improving initial access coverage through SUL-specific criteria when appropriate.
Data Source
AI summary
Supplementary uplink (SUL) may be used in wireless systems. Cell suitability criteria may be provided for cells configured with SUL. A Wireless Transmit/Receive Unit (WTRU) may receive paging with an indication of a carrier (e.g., SUL or regular uplink (RUL)) in which to initiate part or all of an initial access. A WTRU that may be performing response-driven paging may provide (e.g. explicit) beam information for beamforming of a paging message on a non-beamformed SUL. A handover (HO) procedure (e.g., carrier selection, configuration handling, HO failure, etc.) may be provided for a WTRU with a configured SUL. A WTRU may request a change of a configured UL. A WTRU may (e.g., autonomously) perform a switch to a different (e.g., configured) uplink, for example, when one or more conditions may be met (e.g., conditional switch). Semi-persistent scheduling (SPS) resources/configuration may be relocated from a first UL to a second UL.